1 | /* |
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2 | * linux/drivers/char/tty_io.c |
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3 | * |
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4 | * Copyright (C) 1991, 1992 Linus Torvalds |
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5 | */ |
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6 | |
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7 | /* |
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8 | * 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles |
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9 | * or rs-channels. It also implements echoing, cooked mode etc. |
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10 | * |
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11 | * Kill-line thanks to John T Kohl, who also corrected VMIN = VTIME = 0. |
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12 | * |
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13 | * Modified by Theodore Ts'o, 9/14/92, to dynamically allocate the |
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14 | * tty_struct and tty_queue structures. Previously there was an array |
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15 | * of 256 tty_struct's which was statically allocated, and the |
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16 | * tty_queue structures were allocated at boot time. Both are now |
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17 | * dynamically allocated only when the tty is open. |
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18 | * |
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19 | * Also restructured routines so that there is more of a separation |
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20 | * between the high-level tty routines (tty_io.c and tty_ioctl.c) and |
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21 | * the low-level tty routines (serial.c, pty.c, console.c). This |
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22 | * makes for cleaner and more compact code. -TYT, 9/17/92 |
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23 | * |
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24 | * Modified by Fred N. van Kempen, 01/29/93, to add line disciplines |
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25 | * which can be dynamically activated and de-activated by the line |
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26 | * discipline handling modules (like SLIP). |
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27 | * |
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28 | * NOTE: pay no attention to the line discipline code (yet); its |
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29 | * interface is still subject to change in this version... |
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30 | * -- TYT, 1/31/92 |
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31 | * |
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32 | * Added functionality to the OPOST tty handling. No delays, but all |
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33 | * other bits should be there. |
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34 | * -- Nick Holloway <alfie@dcs.warwick.ac.uk>, 27th May 1993. |
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35 | * |
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36 | * Rewrote canonical mode and added more termios flags. |
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37 | * -- julian@uhunix.uhcc.hawaii.edu (J. Cowley), 13Jan94 |
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38 | * |
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39 | * Reorganized FASYNC support so mouse code can share it. |
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40 | * -- ctm@ardi.com, 9Sep95 |
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41 | * |
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42 | * New TIOCLINUX variants added. |
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43 | * -- mj@k332.feld.cvut.cz, 19-Nov-95 |
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44 | * |
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45 | * Restrict vt switching via ioctl() |
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46 | * -- grif@cs.ucr.edu, 5-Dec-95 |
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47 | * |
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48 | * Move console and virtual terminal code to more appropriate files, |
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49 | * implement CONFIG_VT and generalize console device interface. |
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50 | * -- Marko Kohtala <Marko.Kohtala@hut.fi>, March 97 |
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51 | * |
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52 | * Rewrote init_dev and release_dev to eliminate races. |
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53 | * -- Bill Hawes <whawes@star.net>, June 97 |
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54 | * |
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55 | * Added devfs support. |
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56 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 13-Jan-1998 |
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57 | * |
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58 | * Added support for a Unix98-style ptmx device. |
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59 | * -- C. Scott Ananian <cananian@alumni.princeton.edu>, 14-Jan-1998 |
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60 | * |
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61 | * Reduced memory usage for older ARM systems |
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62 | * -- Russell King <rmk@arm.linux.org.uk> |
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63 | * |
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64 | * Move do_SAK() into process context. Less stack use in devfs functions. |
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65 | * alloc_tty_struct() always uses kmalloc() -- Andrew Morton <andrewm@uow.edu.eu> 17Mar01 |
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66 | */ |
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67 | |
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68 | #include <linux/types.h> |
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69 | #include <linux/major.h> |
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70 | #include <linux/errno.h> |
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71 | #include <linux/signal.h> |
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72 | #include <linux/fcntl.h> |
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73 | #include <linux/sched.h> |
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74 | #include <linux/interrupt.h> |
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75 | #include <linux/tty.h> |
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76 | #include <linux/tty_driver.h> |
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77 | #include <linux/tty_flip.h> |
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78 | #include <linux/devpts_fs.h> |
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79 | #include <linux/file.h> |
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80 | #include <linux/console.h> |
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81 | #include <linux/timer.h> |
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82 | #include <linux/ctype.h> |
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83 | #include <linux/kd.h> |
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84 | #include <linux/mm.h> |
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85 | #include <linux/string.h> |
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86 | #include <linux/slab.h> |
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87 | #include <linux/poll.h> |
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88 | #include <linux/proc_fs.h> |
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89 | #include <linux/init.h> |
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90 | #include <linux/module.h> |
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91 | #include <linux/smp_lock.h> |
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92 | #include <linux/device.h> |
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93 | #include <linux/idr.h> |
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94 | #include <linux/wait.h> |
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95 | #include <linux/bitops.h> |
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96 | #include <linux/delay.h> |
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97 | |
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98 | #include <asm/uaccess.h> |
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99 | #include <asm/system.h> |
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100 | |
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101 | #include <linux/kbd_kern.h> |
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102 | #include <linux/vt_kern.h> |
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103 | #include <linux/selection.h> |
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104 | |
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105 | #include <linux/kmod.h> |
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106 | |
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107 | #undef TTY_DEBUG_HANGUP |
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108 | |
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109 | #define TTY_PARANOIA_CHECK 1 |
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110 | #define CHECK_TTY_COUNT 1 |
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111 | |
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112 | struct termios tty_std_termios = { /* for the benefit of tty drivers */ |
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113 | .c_iflag = ICRNL | IXON, |
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114 | .c_oflag = OPOST | ONLCR, |
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115 | .c_cflag = B38400 | CS8 | CREAD | HUPCL, |
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116 | .c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | |
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117 | ECHOCTL | ECHOKE | IEXTEN, |
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118 | .c_cc = INIT_C_CC |
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119 | }; |
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120 | |
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121 | EXPORT_SYMBOL(tty_std_termios); |
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122 | |
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123 | /* This list gets poked at by procfs and various bits of boot up code. This |
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124 | could do with some rationalisation such as pulling the tty proc function |
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125 | into this file */ |
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126 | |
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127 | LIST_HEAD(tty_drivers); /* linked list of tty drivers */ |
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128 | |
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129 | /* Semaphore to protect creating and releasing a tty. This is shared with |
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130 | vt.c for deeply disgusting hack reasons */ |
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131 | DEFINE_MUTEX(tty_mutex); |
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132 | |
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133 | int console_use_vt = 1; |
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134 | |
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135 | #ifdef CONFIG_UNIX98_PTYS |
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136 | extern struct tty_driver *ptm_driver; /* Unix98 pty masters; for /dev/ptmx */ |
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137 | extern int pty_limit; /* Config limit on Unix98 ptys */ |
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138 | static DEFINE_IDR(allocated_ptys); |
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139 | static DECLARE_MUTEX(allocated_ptys_lock); |
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140 | static int ptmx_open(struct inode *, struct file *); |
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141 | #endif |
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142 | |
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143 | extern void disable_early_printk(void); |
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144 | |
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145 | static void initialize_tty_struct(struct tty_struct *tty); |
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146 | |
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147 | static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *); |
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148 | static ssize_t tty_write(struct file *, const char __user *, size_t, loff_t *); |
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149 | ssize_t redirected_tty_write(struct file *, const char __user *, size_t, loff_t *); |
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150 | static unsigned int tty_poll(struct file *, poll_table *); |
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151 | static int tty_open(struct inode *, struct file *); |
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152 | static int tty_release(struct inode *, struct file *); |
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153 | int tty_ioctl(struct inode * inode, struct file * file, |
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154 | unsigned int cmd, unsigned long arg); |
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155 | static int tty_fasync(int fd, struct file * filp, int on); |
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156 | static void release_mem(struct tty_struct *tty, int idx); |
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157 | |
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158 | /** |
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159 | * alloc_tty_struct - allocate a tty object |
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160 | * |
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161 | * Return a new empty tty structure. The data fields have not |
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162 | * been initialized in any way but has been zeroed |
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163 | * |
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164 | * Locking: none |
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165 | * FIXME: use kzalloc |
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166 | */ |
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167 | |
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168 | static struct tty_struct *alloc_tty_struct(void) |
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169 | { |
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170 | struct tty_struct *tty; |
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171 | |
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172 | tty = kmalloc(sizeof(struct tty_struct), GFP_KERNEL); |
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173 | if (tty) |
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174 | memset(tty, 0, sizeof(struct tty_struct)); |
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175 | return tty; |
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176 | } |
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177 | |
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178 | static void tty_buffer_free_all(struct tty_struct *); |
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179 | |
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180 | /** |
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181 | * free_tty_struct - free a disused tty |
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182 | * @tty: tty struct to free |
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183 | * |
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184 | * Free the write buffers, tty queue and tty memory itself. |
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185 | * |
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186 | * Locking: none. Must be called after tty is definitely unused |
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187 | */ |
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188 | |
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189 | static inline void free_tty_struct(struct tty_struct *tty) |
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190 | { |
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191 | kfree(tty->write_buf); |
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192 | tty_buffer_free_all(tty); |
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193 | kfree(tty); |
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194 | } |
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195 | |
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196 | #define TTY_NUMBER(tty) ((tty)->index + (tty)->driver->name_base) |
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197 | |
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198 | /** |
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199 | * tty_name - return tty naming |
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200 | * @tty: tty structure |
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201 | * @buf: buffer for output |
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202 | * |
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203 | * Convert a tty structure into a name. The name reflects the kernel |
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204 | * naming policy and if udev is in use may not reflect user space |
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205 | * |
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206 | * Locking: none |
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207 | */ |
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208 | |
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209 | char *tty_name(struct tty_struct *tty, char *buf) |
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210 | { |
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211 | if (!tty) /* Hmm. NULL pointer. That's fun. */ |
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212 | strcpy(buf, "NULL tty"); |
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213 | else |
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214 | strcpy(buf, tty->name); |
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215 | return buf; |
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216 | } |
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217 | |
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218 | EXPORT_SYMBOL(tty_name); |
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219 | |
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220 | int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, |
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221 | const char *routine) |
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222 | { |
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223 | #ifdef TTY_PARANOIA_CHECK |
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224 | if (!tty) { |
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225 | printk(KERN_WARNING |
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226 | "null TTY for (%d:%d) in %s\n", |
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227 | imajor(inode), iminor(inode), routine); |
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228 | return 1; |
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229 | } |
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230 | if (tty->magic != TTY_MAGIC) { |
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231 | printk(KERN_WARNING |
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232 | "bad magic number for tty struct (%d:%d) in %s\n", |
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233 | imajor(inode), iminor(inode), routine); |
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234 | return 1; |
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235 | } |
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236 | #endif |
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237 | return 0; |
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238 | } |
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239 | |
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240 | static int check_tty_count(struct tty_struct *tty, const char *routine) |
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241 | { |
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242 | #ifdef CHECK_TTY_COUNT |
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243 | struct list_head *p; |
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244 | int count = 0; |
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245 | |
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246 | file_list_lock(); |
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247 | list_for_each(p, &tty->tty_files) { |
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248 | count++; |
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249 | } |
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250 | file_list_unlock(); |
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251 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
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252 | tty->driver->subtype == PTY_TYPE_SLAVE && |
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253 | tty->link && tty->link->count) |
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254 | count++; |
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255 | if (tty->count != count) { |
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256 | printk(KERN_WARNING "Warning: dev (%s) tty->count(%d) " |
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257 | "!= #fd's(%d) in %s\n", |
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258 | tty->name, tty->count, count, routine); |
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259 | return count; |
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260 | } |
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261 | #endif |
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262 | return 0; |
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263 | } |
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264 | |
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265 | /* |
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266 | * Tty buffer allocation management |
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267 | */ |
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268 | |
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269 | |
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270 | /** |
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271 | * tty_buffer_free_all - free buffers used by a tty |
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272 | * @tty: tty to free from |
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273 | * |
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274 | * Remove all the buffers pending on a tty whether queued with data |
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275 | * or in the free ring. Must be called when the tty is no longer in use |
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276 | * |
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277 | * Locking: none |
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278 | */ |
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279 | |
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280 | |
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281 | /** |
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282 | * tty_buffer_free_all - free buffers used by a tty |
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283 | * @tty: tty to free from |
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284 | * |
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285 | * Remove all the buffers pending on a tty whether queued with data |
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286 | * or in the free ring. Must be called when the tty is no longer in use |
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287 | * |
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288 | * Locking: none |
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289 | */ |
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290 | |
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291 | static void tty_buffer_free_all(struct tty_struct *tty) |
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292 | { |
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293 | struct tty_buffer *thead; |
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294 | while((thead = tty->buf.head) != NULL) { |
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295 | tty->buf.head = thead->next; |
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296 | kfree(thead); |
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297 | } |
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298 | while((thead = tty->buf.free) != NULL) { |
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299 | tty->buf.free = thead->next; |
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300 | kfree(thead); |
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301 | } |
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302 | tty->buf.tail = NULL; |
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303 | tty->buf.memory_used = 0; |
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304 | } |
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305 | |
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306 | /** |
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307 | * tty_buffer_init - prepare a tty buffer structure |
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308 | * @tty: tty to initialise |
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309 | * |
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310 | * Set up the initial state of the buffer management for a tty device. |
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311 | * Must be called before the other tty buffer functions are used. |
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312 | * |
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313 | * Locking: none |
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314 | */ |
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315 | |
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316 | static void tty_buffer_init(struct tty_struct *tty) |
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317 | { |
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318 | spin_lock_init(&tty->buf.lock); |
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319 | tty->buf.head = NULL; |
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320 | tty->buf.tail = NULL; |
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321 | tty->buf.free = NULL; |
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322 | tty->buf.memory_used = 0; |
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323 | } |
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324 | |
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325 | /** |
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326 | * tty_buffer_alloc - allocate a tty buffer |
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327 | * @tty: tty device |
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328 | * @size: desired size (characters) |
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329 | * |
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330 | * Allocate a new tty buffer to hold the desired number of characters. |
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331 | * Return NULL if out of memory or the allocation would exceed the |
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332 | * per device queue |
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333 | * |
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334 | * Locking: Caller must hold tty->buf.lock |
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335 | */ |
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336 | |
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337 | static struct tty_buffer *tty_buffer_alloc(struct tty_struct *tty, size_t size) |
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338 | { |
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339 | struct tty_buffer *p; |
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340 | |
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341 | if (tty->buf.memory_used + size > 65536) |
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342 | return NULL; |
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343 | p = kmalloc(sizeof(struct tty_buffer) + 2 * size, GFP_ATOMIC); |
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344 | if(p == NULL) |
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345 | return NULL; |
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346 | p->used = 0; |
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347 | p->size = size; |
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348 | p->next = NULL; |
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349 | p->commit = 0; |
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350 | p->read = 0; |
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351 | p->char_buf_ptr = (char *)(p->data); |
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352 | p->flag_buf_ptr = (unsigned char *)p->char_buf_ptr + size; |
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353 | tty->buf.memory_used += size; |
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354 | return p; |
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355 | } |
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356 | |
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357 | /** |
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358 | * tty_buffer_free - free a tty buffer |
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359 | * @tty: tty owning the buffer |
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360 | * @b: the buffer to free |
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361 | * |
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362 | * Free a tty buffer, or add it to the free list according to our |
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363 | * internal strategy |
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364 | * |
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365 | * Locking: Caller must hold tty->buf.lock |
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366 | */ |
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367 | |
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368 | static void tty_buffer_free(struct tty_struct *tty, struct tty_buffer *b) |
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369 | { |
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370 | /* Dumb strategy for now - should keep some stats */ |
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371 | tty->buf.memory_used -= b->size; |
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372 | WARN_ON(tty->buf.memory_used < 0); |
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373 | |
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374 | if(b->size >= 512) |
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375 | kfree(b); |
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376 | else { |
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377 | b->next = tty->buf.free; |
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378 | tty->buf.free = b; |
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379 | } |
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380 | } |
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381 | |
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382 | /** |
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383 | * tty_buffer_find - find a free tty buffer |
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384 | * @tty: tty owning the buffer |
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385 | * @size: characters wanted |
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386 | * |
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387 | * Locate an existing suitable tty buffer or if we are lacking one then |
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388 | * allocate a new one. We round our buffers off in 256 character chunks |
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389 | * to get better allocation behaviour. |
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390 | * |
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391 | * Locking: Caller must hold tty->buf.lock |
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392 | */ |
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393 | |
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394 | static struct tty_buffer *tty_buffer_find(struct tty_struct *tty, size_t size) |
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395 | { |
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396 | struct tty_buffer **tbh = &tty->buf.free; |
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397 | while((*tbh) != NULL) { |
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398 | struct tty_buffer *t = *tbh; |
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399 | if(t->size >= size) { |
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400 | *tbh = t->next; |
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401 | t->next = NULL; |
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402 | t->used = 0; |
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403 | t->commit = 0; |
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404 | t->read = 0; |
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405 | tty->buf.memory_used += t->size; |
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406 | return t; |
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407 | } |
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408 | tbh = &((*tbh)->next); |
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409 | } |
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410 | /* Round the buffer size out */ |
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411 | size = (size + 0xFF) & ~ 0xFF; |
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412 | return tty_buffer_alloc(tty, size); |
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413 | /* Should possibly check if this fails for the largest buffer we |
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414 | have queued and recycle that ? */ |
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415 | } |
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416 | |
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417 | /** |
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418 | * tty_buffer_request_room - grow tty buffer if needed |
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419 | * @tty: tty structure |
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420 | * @size: size desired |
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421 | * |
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422 | * Make at least size bytes of linear space available for the tty |
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423 | * buffer. If we fail return the size we managed to find. |
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424 | * |
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425 | * Locking: Takes tty->buf.lock |
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426 | */ |
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427 | int tty_buffer_request_room(struct tty_struct *tty, size_t size) |
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428 | { |
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429 | struct tty_buffer *b, *n; |
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430 | int left; |
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431 | unsigned long flags; |
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432 | |
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433 | spin_lock_irqsave(&tty->buf.lock, flags); |
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434 | |
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435 | /* OPTIMISATION: We could keep a per tty "zero" sized buffer to |
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436 | remove this conditional if its worth it. This would be invisible |
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437 | to the callers */ |
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438 | if ((b = tty->buf.tail) != NULL) |
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439 | left = b->size - b->used; |
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440 | else |
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441 | left = 0; |
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442 | |
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443 | if (left < size) { |
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444 | /* This is the slow path - looking for new buffers to use */ |
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445 | if ((n = tty_buffer_find(tty, size)) != NULL) { |
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446 | if (b != NULL) { |
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447 | b->next = n; |
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448 | b->commit = b->used; |
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449 | } else |
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450 | tty->buf.head = n; |
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451 | tty->buf.tail = n; |
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452 | } else |
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453 | size = left; |
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454 | } |
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455 | |
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456 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
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457 | return size; |
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458 | } |
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459 | EXPORT_SYMBOL_GPL(tty_buffer_request_room); |
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460 | |
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461 | /** |
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462 | * tty_insert_flip_string - Add characters to the tty buffer |
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463 | * @tty: tty structure |
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464 | * @chars: characters |
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465 | * @size: size |
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466 | * |
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467 | * Queue a series of bytes to the tty buffering. All the characters |
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468 | * passed are marked as without error. Returns the number added. |
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469 | * |
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470 | * Locking: Called functions may take tty->buf.lock |
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471 | */ |
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472 | |
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473 | int tty_insert_flip_string(struct tty_struct *tty, const unsigned char *chars, |
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474 | size_t size) |
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475 | { |
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476 | int copied = 0; |
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477 | do { |
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478 | int space = tty_buffer_request_room(tty, size - copied); |
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479 | struct tty_buffer *tb = tty->buf.tail; |
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480 | /* If there is no space then tb may be NULL */ |
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481 | if(unlikely(space == 0)) |
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482 | break; |
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483 | memcpy(tb->char_buf_ptr + tb->used, chars, space); |
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484 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); |
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485 | tb->used += space; |
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486 | copied += space; |
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487 | chars += space; |
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488 | } |
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489 | /* There is a small chance that we need to split the data over |
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490 | several buffers. If this is the case we must loop */ |
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491 | while (unlikely(size > copied)); |
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492 | return copied; |
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493 | } |
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494 | EXPORT_SYMBOL(tty_insert_flip_string); |
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495 | |
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496 | /** |
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497 | * tty_insert_flip_string_flags - Add characters to the tty buffer |
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498 | * @tty: tty structure |
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499 | * @chars: characters |
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500 | * @flags: flag bytes |
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501 | * @size: size |
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502 | * |
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503 | * Queue a series of bytes to the tty buffering. For each character |
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504 | * the flags array indicates the status of the character. Returns the |
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505 | * number added. |
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506 | * |
---|
507 | * Locking: Called functions may take tty->buf.lock |
---|
508 | */ |
---|
509 | |
---|
510 | int tty_insert_flip_string_flags(struct tty_struct *tty, |
---|
511 | const unsigned char *chars, const char *flags, size_t size) |
---|
512 | { |
---|
513 | int copied = 0; |
---|
514 | do { |
---|
515 | int space = tty_buffer_request_room(tty, size - copied); |
---|
516 | struct tty_buffer *tb = tty->buf.tail; |
---|
517 | /* If there is no space then tb may be NULL */ |
---|
518 | if(unlikely(space == 0)) |
---|
519 | break; |
---|
520 | memcpy(tb->char_buf_ptr + tb->used, chars, space); |
---|
521 | memcpy(tb->flag_buf_ptr + tb->used, flags, space); |
---|
522 | tb->used += space; |
---|
523 | copied += space; |
---|
524 | chars += space; |
---|
525 | flags += space; |
---|
526 | } |
---|
527 | /* There is a small chance that we need to split the data over |
---|
528 | several buffers. If this is the case we must loop */ |
---|
529 | while (unlikely(size > copied)); |
---|
530 | return copied; |
---|
531 | } |
---|
532 | EXPORT_SYMBOL(tty_insert_flip_string_flags); |
---|
533 | |
---|
534 | /** |
---|
535 | * tty_schedule_flip - push characters to ldisc |
---|
536 | * @tty: tty to push from |
---|
537 | * |
---|
538 | * Takes any pending buffers and transfers their ownership to the |
---|
539 | * ldisc side of the queue. It then schedules those characters for |
---|
540 | * processing by the line discipline. |
---|
541 | * |
---|
542 | * Locking: Takes tty->buf.lock |
---|
543 | */ |
---|
544 | |
---|
545 | void tty_schedule_flip(struct tty_struct *tty) |
---|
546 | { |
---|
547 | unsigned long flags; |
---|
548 | spin_lock_irqsave(&tty->buf.lock, flags); |
---|
549 | if (tty->buf.tail != NULL) |
---|
550 | tty->buf.tail->commit = tty->buf.tail->used; |
---|
551 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
---|
552 | schedule_delayed_work(&tty->buf.work, 1); |
---|
553 | } |
---|
554 | EXPORT_SYMBOL(tty_schedule_flip); |
---|
555 | |
---|
556 | /** |
---|
557 | * tty_prepare_flip_string - make room for characters |
---|
558 | * @tty: tty |
---|
559 | * @chars: return pointer for character write area |
---|
560 | * @size: desired size |
---|
561 | * |
---|
562 | * Prepare a block of space in the buffer for data. Returns the length |
---|
563 | * available and buffer pointer to the space which is now allocated and |
---|
564 | * accounted for as ready for normal characters. This is used for drivers |
---|
565 | * that need their own block copy routines into the buffer. There is no |
---|
566 | * guarantee the buffer is a DMA target! |
---|
567 | * |
---|
568 | * Locking: May call functions taking tty->buf.lock |
---|
569 | */ |
---|
570 | |
---|
571 | int tty_prepare_flip_string(struct tty_struct *tty, unsigned char **chars, size_t size) |
---|
572 | { |
---|
573 | int space = tty_buffer_request_room(tty, size); |
---|
574 | if (likely(space)) { |
---|
575 | struct tty_buffer *tb = tty->buf.tail; |
---|
576 | *chars = tb->char_buf_ptr + tb->used; |
---|
577 | memset(tb->flag_buf_ptr + tb->used, TTY_NORMAL, space); |
---|
578 | tb->used += space; |
---|
579 | } |
---|
580 | return space; |
---|
581 | } |
---|
582 | |
---|
583 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string); |
---|
584 | |
---|
585 | /** |
---|
586 | * tty_prepare_flip_string_flags - make room for characters |
---|
587 | * @tty: tty |
---|
588 | * @chars: return pointer for character write area |
---|
589 | * @flags: return pointer for status flag write area |
---|
590 | * @size: desired size |
---|
591 | * |
---|
592 | * Prepare a block of space in the buffer for data. Returns the length |
---|
593 | * available and buffer pointer to the space which is now allocated and |
---|
594 | * accounted for as ready for characters. This is used for drivers |
---|
595 | * that need their own block copy routines into the buffer. There is no |
---|
596 | * guarantee the buffer is a DMA target! |
---|
597 | * |
---|
598 | * Locking: May call functions taking tty->buf.lock |
---|
599 | */ |
---|
600 | |
---|
601 | int tty_prepare_flip_string_flags(struct tty_struct *tty, unsigned char **chars, char **flags, size_t size) |
---|
602 | { |
---|
603 | int space = tty_buffer_request_room(tty, size); |
---|
604 | if (likely(space)) { |
---|
605 | struct tty_buffer *tb = tty->buf.tail; |
---|
606 | *chars = tb->char_buf_ptr + tb->used; |
---|
607 | *flags = tb->flag_buf_ptr + tb->used; |
---|
608 | tb->used += space; |
---|
609 | } |
---|
610 | return space; |
---|
611 | } |
---|
612 | |
---|
613 | EXPORT_SYMBOL_GPL(tty_prepare_flip_string_flags); |
---|
614 | |
---|
615 | |
---|
616 | |
---|
617 | /** |
---|
618 | * tty_set_termios_ldisc - set ldisc field |
---|
619 | * @tty: tty structure |
---|
620 | * @num: line discipline number |
---|
621 | * |
---|
622 | * This is probably overkill for real world processors but |
---|
623 | * they are not on hot paths so a little discipline won't do |
---|
624 | * any harm. |
---|
625 | * |
---|
626 | * Locking: takes termios_sem |
---|
627 | */ |
---|
628 | |
---|
629 | static void tty_set_termios_ldisc(struct tty_struct *tty, int num) |
---|
630 | { |
---|
631 | down(&tty->termios_sem); |
---|
632 | tty->termios->c_line = num; |
---|
633 | up(&tty->termios_sem); |
---|
634 | } |
---|
635 | |
---|
636 | /* |
---|
637 | * This guards the refcounted line discipline lists. The lock |
---|
638 | * must be taken with irqs off because there are hangup path |
---|
639 | * callers who will do ldisc lookups and cannot sleep. |
---|
640 | */ |
---|
641 | |
---|
642 | static DEFINE_SPINLOCK(tty_ldisc_lock); |
---|
643 | static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait); |
---|
644 | static struct tty_ldisc tty_ldiscs[NR_LDISCS]; /* line disc dispatch table */ |
---|
645 | |
---|
646 | /** |
---|
647 | * tty_register_ldisc - install a line discipline |
---|
648 | * @disc: ldisc number |
---|
649 | * @new_ldisc: pointer to the ldisc object |
---|
650 | * |
---|
651 | * Installs a new line discipline into the kernel. The discipline |
---|
652 | * is set up as unreferenced and then made available to the kernel |
---|
653 | * from this point onwards. |
---|
654 | * |
---|
655 | * Locking: |
---|
656 | * takes tty_ldisc_lock to guard against ldisc races |
---|
657 | */ |
---|
658 | |
---|
659 | int tty_register_ldisc(int disc, struct tty_ldisc *new_ldisc) |
---|
660 | { |
---|
661 | unsigned long flags; |
---|
662 | int ret = 0; |
---|
663 | |
---|
664 | if (disc < N_TTY || disc >= NR_LDISCS) |
---|
665 | return -EINVAL; |
---|
666 | |
---|
667 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
668 | tty_ldiscs[disc] = *new_ldisc; |
---|
669 | tty_ldiscs[disc].num = disc; |
---|
670 | tty_ldiscs[disc].flags |= LDISC_FLAG_DEFINED; |
---|
671 | tty_ldiscs[disc].refcount = 0; |
---|
672 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
673 | |
---|
674 | return ret; |
---|
675 | } |
---|
676 | EXPORT_SYMBOL(tty_register_ldisc); |
---|
677 | |
---|
678 | /** |
---|
679 | * tty_unregister_ldisc - unload a line discipline |
---|
680 | * @disc: ldisc number |
---|
681 | * @new_ldisc: pointer to the ldisc object |
---|
682 | * |
---|
683 | * Remove a line discipline from the kernel providing it is not |
---|
684 | * currently in use. |
---|
685 | * |
---|
686 | * Locking: |
---|
687 | * takes tty_ldisc_lock to guard against ldisc races |
---|
688 | */ |
---|
689 | |
---|
690 | int tty_unregister_ldisc(int disc) |
---|
691 | { |
---|
692 | unsigned long flags; |
---|
693 | int ret = 0; |
---|
694 | |
---|
695 | if (disc < N_TTY || disc >= NR_LDISCS) |
---|
696 | return -EINVAL; |
---|
697 | |
---|
698 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
699 | if (tty_ldiscs[disc].refcount) |
---|
700 | ret = -EBUSY; |
---|
701 | else |
---|
702 | tty_ldiscs[disc].flags &= ~LDISC_FLAG_DEFINED; |
---|
703 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
704 | |
---|
705 | return ret; |
---|
706 | } |
---|
707 | EXPORT_SYMBOL(tty_unregister_ldisc); |
---|
708 | |
---|
709 | /** |
---|
710 | * tty_ldisc_get - take a reference to an ldisc |
---|
711 | * @disc: ldisc number |
---|
712 | * |
---|
713 | * Takes a reference to a line discipline. Deals with refcounts and |
---|
714 | * module locking counts. Returns NULL if the discipline is not available. |
---|
715 | * Returns a pointer to the discipline and bumps the ref count if it is |
---|
716 | * available |
---|
717 | * |
---|
718 | * Locking: |
---|
719 | * takes tty_ldisc_lock to guard against ldisc races |
---|
720 | */ |
---|
721 | |
---|
722 | struct tty_ldisc *tty_ldisc_get(int disc) |
---|
723 | { |
---|
724 | unsigned long flags; |
---|
725 | struct tty_ldisc *ld; |
---|
726 | |
---|
727 | if (disc < N_TTY || disc >= NR_LDISCS) |
---|
728 | return NULL; |
---|
729 | |
---|
730 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
731 | |
---|
732 | ld = &tty_ldiscs[disc]; |
---|
733 | /* Check the entry is defined */ |
---|
734 | if(ld->flags & LDISC_FLAG_DEFINED) |
---|
735 | { |
---|
736 | /* If the module is being unloaded we can't use it */ |
---|
737 | if (!try_module_get(ld->owner)) |
---|
738 | ld = NULL; |
---|
739 | else /* lock it */ |
---|
740 | ld->refcount++; |
---|
741 | } |
---|
742 | else |
---|
743 | ld = NULL; |
---|
744 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
745 | return ld; |
---|
746 | } |
---|
747 | |
---|
748 | EXPORT_SYMBOL_GPL(tty_ldisc_get); |
---|
749 | |
---|
750 | /** |
---|
751 | * tty_ldisc_put - drop ldisc reference |
---|
752 | * @disc: ldisc number |
---|
753 | * |
---|
754 | * Drop a reference to a line discipline. Manage refcounts and |
---|
755 | * module usage counts |
---|
756 | * |
---|
757 | * Locking: |
---|
758 | * takes tty_ldisc_lock to guard against ldisc races |
---|
759 | */ |
---|
760 | |
---|
761 | void tty_ldisc_put(int disc) |
---|
762 | { |
---|
763 | struct tty_ldisc *ld; |
---|
764 | unsigned long flags; |
---|
765 | |
---|
766 | BUG_ON(disc < N_TTY || disc >= NR_LDISCS); |
---|
767 | |
---|
768 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
769 | ld = &tty_ldiscs[disc]; |
---|
770 | BUG_ON(ld->refcount == 0); |
---|
771 | ld->refcount--; |
---|
772 | module_put(ld->owner); |
---|
773 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
774 | } |
---|
775 | |
---|
776 | EXPORT_SYMBOL_GPL(tty_ldisc_put); |
---|
777 | |
---|
778 | /** |
---|
779 | * tty_ldisc_assign - set ldisc on a tty |
---|
780 | * @tty: tty to assign |
---|
781 | * @ld: line discipline |
---|
782 | * |
---|
783 | * Install an instance of a line discipline into a tty structure. The |
---|
784 | * ldisc must have a reference count above zero to ensure it remains/ |
---|
785 | * The tty instance refcount starts at zero. |
---|
786 | * |
---|
787 | * Locking: |
---|
788 | * Caller must hold references |
---|
789 | */ |
---|
790 | |
---|
791 | static void tty_ldisc_assign(struct tty_struct *tty, struct tty_ldisc *ld) |
---|
792 | { |
---|
793 | tty->ldisc = *ld; |
---|
794 | tty->ldisc.refcount = 0; |
---|
795 | } |
---|
796 | |
---|
797 | /** |
---|
798 | * tty_ldisc_try - internal helper |
---|
799 | * @tty: the tty |
---|
800 | * |
---|
801 | * Make a single attempt to grab and bump the refcount on |
---|
802 | * the tty ldisc. Return 0 on failure or 1 on success. This is |
---|
803 | * used to implement both the waiting and non waiting versions |
---|
804 | * of tty_ldisc_ref |
---|
805 | * |
---|
806 | * Locking: takes tty_ldisc_lock |
---|
807 | */ |
---|
808 | |
---|
809 | static int tty_ldisc_try(struct tty_struct *tty) |
---|
810 | { |
---|
811 | unsigned long flags; |
---|
812 | struct tty_ldisc *ld; |
---|
813 | int ret = 0; |
---|
814 | |
---|
815 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
816 | ld = &tty->ldisc; |
---|
817 | if(test_bit(TTY_LDISC, &tty->flags)) |
---|
818 | { |
---|
819 | ld->refcount++; |
---|
820 | ret = 1; |
---|
821 | } |
---|
822 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
823 | return ret; |
---|
824 | } |
---|
825 | |
---|
826 | /** |
---|
827 | * tty_ldisc_ref_wait - wait for the tty ldisc |
---|
828 | * @tty: tty device |
---|
829 | * |
---|
830 | * Dereference the line discipline for the terminal and take a |
---|
831 | * reference to it. If the line discipline is in flux then |
---|
832 | * wait patiently until it changes. |
---|
833 | * |
---|
834 | * Note: Must not be called from an IRQ/timer context. The caller |
---|
835 | * must also be careful not to hold other locks that will deadlock |
---|
836 | * against a discipline change, such as an existing ldisc reference |
---|
837 | * (which we check for) |
---|
838 | * |
---|
839 | * Locking: call functions take tty_ldisc_lock |
---|
840 | */ |
---|
841 | |
---|
842 | struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty) |
---|
843 | { |
---|
844 | /* wait_event is a macro */ |
---|
845 | wait_event(tty_ldisc_wait, tty_ldisc_try(tty)); |
---|
846 | if(tty->ldisc.refcount == 0) |
---|
847 | printk(KERN_ERR "tty_ldisc_ref_wait\n"); |
---|
848 | return &tty->ldisc; |
---|
849 | } |
---|
850 | |
---|
851 | EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait); |
---|
852 | |
---|
853 | /** |
---|
854 | * tty_ldisc_ref - get the tty ldisc |
---|
855 | * @tty: tty device |
---|
856 | * |
---|
857 | * Dereference the line discipline for the terminal and take a |
---|
858 | * reference to it. If the line discipline is in flux then |
---|
859 | * return NULL. Can be called from IRQ and timer functions. |
---|
860 | * |
---|
861 | * Locking: called functions take tty_ldisc_lock |
---|
862 | */ |
---|
863 | |
---|
864 | struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty) |
---|
865 | { |
---|
866 | if(tty_ldisc_try(tty)) |
---|
867 | return &tty->ldisc; |
---|
868 | return NULL; |
---|
869 | } |
---|
870 | |
---|
871 | EXPORT_SYMBOL_GPL(tty_ldisc_ref); |
---|
872 | |
---|
873 | /** |
---|
874 | * tty_ldisc_deref - free a tty ldisc reference |
---|
875 | * @ld: reference to free up |
---|
876 | * |
---|
877 | * Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May |
---|
878 | * be called in IRQ context. |
---|
879 | * |
---|
880 | * Locking: takes tty_ldisc_lock |
---|
881 | */ |
---|
882 | |
---|
883 | void tty_ldisc_deref(struct tty_ldisc *ld) |
---|
884 | { |
---|
885 | unsigned long flags; |
---|
886 | |
---|
887 | BUG_ON(ld == NULL); |
---|
888 | |
---|
889 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
890 | if(ld->refcount == 0) |
---|
891 | printk(KERN_ERR "tty_ldisc_deref: no references.\n"); |
---|
892 | else |
---|
893 | ld->refcount--; |
---|
894 | if(ld->refcount == 0) |
---|
895 | wake_up(&tty_ldisc_wait); |
---|
896 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
897 | } |
---|
898 | |
---|
899 | EXPORT_SYMBOL_GPL(tty_ldisc_deref); |
---|
900 | |
---|
901 | /** |
---|
902 | * tty_ldisc_enable - allow ldisc use |
---|
903 | * @tty: terminal to activate ldisc on |
---|
904 | * |
---|
905 | * Set the TTY_LDISC flag when the line discipline can be called |
---|
906 | * again. Do neccessary wakeups for existing sleepers. |
---|
907 | * |
---|
908 | * Note: nobody should set this bit except via this function. Clearing |
---|
909 | * directly is allowed. |
---|
910 | */ |
---|
911 | |
---|
912 | static void tty_ldisc_enable(struct tty_struct *tty) |
---|
913 | { |
---|
914 | set_bit(TTY_LDISC, &tty->flags); |
---|
915 | wake_up(&tty_ldisc_wait); |
---|
916 | } |
---|
917 | |
---|
918 | /** |
---|
919 | * tty_set_ldisc - set line discipline |
---|
920 | * @tty: the terminal to set |
---|
921 | * @ldisc: the line discipline |
---|
922 | * |
---|
923 | * Set the discipline of a tty line. Must be called from a process |
---|
924 | * context. |
---|
925 | * |
---|
926 | * Locking: takes tty_ldisc_lock. |
---|
927 | * called functions take termios_sem |
---|
928 | */ |
---|
929 | |
---|
930 | static int tty_set_ldisc(struct tty_struct *tty, int ldisc) |
---|
931 | { |
---|
932 | int retval = 0; |
---|
933 | struct tty_ldisc o_ldisc; |
---|
934 | char buf[64]; |
---|
935 | int work; |
---|
936 | unsigned long flags; |
---|
937 | struct tty_ldisc *ld; |
---|
938 | struct tty_struct *o_tty; |
---|
939 | |
---|
940 | if ((ldisc < N_TTY) || (ldisc >= NR_LDISCS)) |
---|
941 | return -EINVAL; |
---|
942 | |
---|
943 | restart: |
---|
944 | |
---|
945 | ld = tty_ldisc_get(ldisc); |
---|
946 | /* Eduardo Blanco <ejbs@cs.cs.com.uy> */ |
---|
947 | /* Cyrus Durgin <cider@speakeasy.org> */ |
---|
948 | if (ld == NULL) { |
---|
949 | request_module("tty-ldisc-%d", ldisc); |
---|
950 | ld = tty_ldisc_get(ldisc); |
---|
951 | } |
---|
952 | if (ld == NULL) |
---|
953 | return -EINVAL; |
---|
954 | |
---|
955 | /* |
---|
956 | * No more input please, we are switching. The new ldisc |
---|
957 | * will update this value in the ldisc open function |
---|
958 | */ |
---|
959 | |
---|
960 | tty->receive_room = 0; |
---|
961 | |
---|
962 | /* |
---|
963 | * Problem: What do we do if this blocks ? |
---|
964 | */ |
---|
965 | |
---|
966 | tty_wait_until_sent(tty, 0); |
---|
967 | |
---|
968 | if (tty->ldisc.num == ldisc) { |
---|
969 | tty_ldisc_put(ldisc); |
---|
970 | return 0; |
---|
971 | } |
---|
972 | |
---|
973 | o_ldisc = tty->ldisc; |
---|
974 | o_tty = tty->link; |
---|
975 | |
---|
976 | /* |
---|
977 | * Make sure we don't change while someone holds a |
---|
978 | * reference to the line discipline. The TTY_LDISC bit |
---|
979 | * prevents anyone taking a reference once it is clear. |
---|
980 | * We need the lock to avoid racing reference takers. |
---|
981 | */ |
---|
982 | |
---|
983 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
984 | if (tty->ldisc.refcount || (o_tty && o_tty->ldisc.refcount)) { |
---|
985 | if(tty->ldisc.refcount) { |
---|
986 | /* Free the new ldisc we grabbed. Must drop the lock |
---|
987 | first. */ |
---|
988 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
989 | tty_ldisc_put(ldisc); |
---|
990 | /* |
---|
991 | * There are several reasons we may be busy, including |
---|
992 | * random momentary I/O traffic. We must therefore |
---|
993 | * retry. We could distinguish between blocking ops |
---|
994 | * and retries if we made tty_ldisc_wait() smarter. That |
---|
995 | * is up for discussion. |
---|
996 | */ |
---|
997 | if (wait_event_interruptible(tty_ldisc_wait, tty->ldisc.refcount == 0) < 0) |
---|
998 | return -ERESTARTSYS; |
---|
999 | goto restart; |
---|
1000 | } |
---|
1001 | if(o_tty && o_tty->ldisc.refcount) { |
---|
1002 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
1003 | tty_ldisc_put(ldisc); |
---|
1004 | if (wait_event_interruptible(tty_ldisc_wait, o_tty->ldisc.refcount == 0) < 0) |
---|
1005 | return -ERESTARTSYS; |
---|
1006 | goto restart; |
---|
1007 | } |
---|
1008 | } |
---|
1009 | |
---|
1010 | /* if the TTY_LDISC bit is set, then we are racing against another ldisc change */ |
---|
1011 | |
---|
1012 | if (!test_bit(TTY_LDISC, &tty->flags)) { |
---|
1013 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
1014 | tty_ldisc_put(ldisc); |
---|
1015 | ld = tty_ldisc_ref_wait(tty); |
---|
1016 | tty_ldisc_deref(ld); |
---|
1017 | goto restart; |
---|
1018 | } |
---|
1019 | |
---|
1020 | clear_bit(TTY_LDISC, &tty->flags); |
---|
1021 | if (o_tty) |
---|
1022 | clear_bit(TTY_LDISC, &o_tty->flags); |
---|
1023 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
1024 | |
---|
1025 | /* |
---|
1026 | * From this point on we know nobody has an ldisc |
---|
1027 | * usage reference, nor can they obtain one until |
---|
1028 | * we say so later on. |
---|
1029 | */ |
---|
1030 | |
---|
1031 | work = cancel_delayed_work(&tty->buf.work); |
---|
1032 | /* |
---|
1033 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
---|
1034 | */ |
---|
1035 | |
---|
1036 | flush_scheduled_work(); |
---|
1037 | /* Shutdown the current discipline. */ |
---|
1038 | if (tty->ldisc.close) |
---|
1039 | (tty->ldisc.close)(tty); |
---|
1040 | |
---|
1041 | /* Now set up the new line discipline. */ |
---|
1042 | tty_ldisc_assign(tty, ld); |
---|
1043 | tty_set_termios_ldisc(tty, ldisc); |
---|
1044 | if (tty->ldisc.open) |
---|
1045 | retval = (tty->ldisc.open)(tty); |
---|
1046 | if (retval < 0) { |
---|
1047 | tty_ldisc_put(ldisc); |
---|
1048 | /* There is an outstanding reference here so this is safe */ |
---|
1049 | tty_ldisc_assign(tty, tty_ldisc_get(o_ldisc.num)); |
---|
1050 | tty_set_termios_ldisc(tty, tty->ldisc.num); |
---|
1051 | if (tty->ldisc.open && (tty->ldisc.open(tty) < 0)) { |
---|
1052 | tty_ldisc_put(o_ldisc.num); |
---|
1053 | /* This driver is always present */ |
---|
1054 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); |
---|
1055 | tty_set_termios_ldisc(tty, N_TTY); |
---|
1056 | if (tty->ldisc.open) { |
---|
1057 | int r = tty->ldisc.open(tty); |
---|
1058 | |
---|
1059 | if (r < 0) |
---|
1060 | panic("Couldn't open N_TTY ldisc for " |
---|
1061 | "%s --- error %d.", |
---|
1062 | tty_name(tty, buf), r); |
---|
1063 | } |
---|
1064 | } |
---|
1065 | } |
---|
1066 | /* At this point we hold a reference to the new ldisc and a |
---|
1067 | a reference to the old ldisc. If we ended up flipping back |
---|
1068 | to the existing ldisc we have two references to it */ |
---|
1069 | |
---|
1070 | if (tty->ldisc.num != o_ldisc.num && tty->driver->set_ldisc) |
---|
1071 | tty->driver->set_ldisc(tty); |
---|
1072 | |
---|
1073 | tty_ldisc_put(o_ldisc.num); |
---|
1074 | |
---|
1075 | /* |
---|
1076 | * Allow ldisc referencing to occur as soon as the driver |
---|
1077 | * ldisc callback completes. |
---|
1078 | */ |
---|
1079 | |
---|
1080 | tty_ldisc_enable(tty); |
---|
1081 | if (o_tty) |
---|
1082 | tty_ldisc_enable(o_tty); |
---|
1083 | |
---|
1084 | /* Restart it in case no characters kick it off. Safe if |
---|
1085 | already running */ |
---|
1086 | if (work) |
---|
1087 | schedule_delayed_work(&tty->buf.work, 1); |
---|
1088 | return retval; |
---|
1089 | } |
---|
1090 | |
---|
1091 | /** |
---|
1092 | * get_tty_driver - find device of a tty |
---|
1093 | * @dev_t: device identifier |
---|
1094 | * @index: returns the index of the tty |
---|
1095 | * |
---|
1096 | * This routine returns a tty driver structure, given a device number |
---|
1097 | * and also passes back the index number. |
---|
1098 | * |
---|
1099 | * Locking: caller must hold tty_mutex |
---|
1100 | */ |
---|
1101 | |
---|
1102 | static struct tty_driver *get_tty_driver(dev_t device, int *index) |
---|
1103 | { |
---|
1104 | struct tty_driver *p; |
---|
1105 | |
---|
1106 | list_for_each_entry(p, &tty_drivers, tty_drivers) { |
---|
1107 | dev_t base = MKDEV(p->major, p->minor_start); |
---|
1108 | if (device < base || device >= base + p->num) |
---|
1109 | continue; |
---|
1110 | *index = device - base; |
---|
1111 | return p; |
---|
1112 | } |
---|
1113 | return NULL; |
---|
1114 | } |
---|
1115 | |
---|
1116 | /** |
---|
1117 | * tty_check_change - check for POSIX terminal changes |
---|
1118 | * @tty: tty to check |
---|
1119 | * |
---|
1120 | * If we try to write to, or set the state of, a terminal and we're |
---|
1121 | * not in the foreground, send a SIGTTOU. If the signal is blocked or |
---|
1122 | * ignored, go ahead and perform the operation. (POSIX 7.2) |
---|
1123 | * |
---|
1124 | * Locking: none |
---|
1125 | */ |
---|
1126 | |
---|
1127 | int tty_check_change(struct tty_struct * tty) |
---|
1128 | { |
---|
1129 | if (current->signal->tty != tty) |
---|
1130 | return 0; |
---|
1131 | if (tty->pgrp <= 0) { |
---|
1132 | printk(KERN_WARNING "tty_check_change: tty->pgrp <= 0!\n"); |
---|
1133 | return 0; |
---|
1134 | } |
---|
1135 | if (process_group(current) == tty->pgrp) |
---|
1136 | return 0; |
---|
1137 | if (is_ignored(SIGTTOU)) |
---|
1138 | return 0; |
---|
1139 | if (is_orphaned_pgrp(process_group(current))) |
---|
1140 | return -EIO; |
---|
1141 | (void) kill_pg(process_group(current), SIGTTOU, 1); |
---|
1142 | return -ERESTARTSYS; |
---|
1143 | } |
---|
1144 | |
---|
1145 | EXPORT_SYMBOL(tty_check_change); |
---|
1146 | |
---|
1147 | static ssize_t hung_up_tty_read(struct file * file, char __user * buf, |
---|
1148 | size_t count, loff_t *ppos) |
---|
1149 | { |
---|
1150 | return 0; |
---|
1151 | } |
---|
1152 | |
---|
1153 | static ssize_t hung_up_tty_write(struct file * file, const char __user * buf, |
---|
1154 | size_t count, loff_t *ppos) |
---|
1155 | { |
---|
1156 | return -EIO; |
---|
1157 | } |
---|
1158 | |
---|
1159 | /* No kernel lock held - none needed ;) */ |
---|
1160 | static unsigned int hung_up_tty_poll(struct file * filp, poll_table * wait) |
---|
1161 | { |
---|
1162 | return POLLIN | POLLOUT | POLLERR | POLLHUP | POLLRDNORM | POLLWRNORM; |
---|
1163 | } |
---|
1164 | |
---|
1165 | static int hung_up_tty_ioctl(struct inode * inode, struct file * file, |
---|
1166 | unsigned int cmd, unsigned long arg) |
---|
1167 | { |
---|
1168 | return cmd == TIOCSPGRP ? -ENOTTY : -EIO; |
---|
1169 | } |
---|
1170 | |
---|
1171 | static const struct file_operations tty_fops = { |
---|
1172 | .llseek = no_llseek, |
---|
1173 | .read = tty_read, |
---|
1174 | .write = tty_write, |
---|
1175 | .poll = tty_poll, |
---|
1176 | .ioctl = tty_ioctl, |
---|
1177 | .open = tty_open, |
---|
1178 | .release = tty_release, |
---|
1179 | .fasync = tty_fasync, |
---|
1180 | }; |
---|
1181 | |
---|
1182 | #ifdef CONFIG_UNIX98_PTYS |
---|
1183 | static const struct file_operations ptmx_fops = { |
---|
1184 | .llseek = no_llseek, |
---|
1185 | .read = tty_read, |
---|
1186 | .write = tty_write, |
---|
1187 | .poll = tty_poll, |
---|
1188 | .ioctl = tty_ioctl, |
---|
1189 | .open = ptmx_open, |
---|
1190 | .release = tty_release, |
---|
1191 | .fasync = tty_fasync, |
---|
1192 | }; |
---|
1193 | #endif |
---|
1194 | |
---|
1195 | static const struct file_operations console_fops = { |
---|
1196 | .llseek = no_llseek, |
---|
1197 | .read = tty_read, |
---|
1198 | .write = redirected_tty_write, |
---|
1199 | .poll = tty_poll, |
---|
1200 | .ioctl = tty_ioctl, |
---|
1201 | .open = tty_open, |
---|
1202 | .release = tty_release, |
---|
1203 | .fasync = tty_fasync, |
---|
1204 | }; |
---|
1205 | |
---|
1206 | static const struct file_operations hung_up_tty_fops = { |
---|
1207 | .llseek = no_llseek, |
---|
1208 | .read = hung_up_tty_read, |
---|
1209 | .write = hung_up_tty_write, |
---|
1210 | .poll = hung_up_tty_poll, |
---|
1211 | .ioctl = hung_up_tty_ioctl, |
---|
1212 | .release = tty_release, |
---|
1213 | }; |
---|
1214 | |
---|
1215 | static DEFINE_SPINLOCK(redirect_lock); |
---|
1216 | static struct file *redirect; |
---|
1217 | |
---|
1218 | /** |
---|
1219 | * tty_wakeup - request more data |
---|
1220 | * @tty: terminal |
---|
1221 | * |
---|
1222 | * Internal and external helper for wakeups of tty. This function |
---|
1223 | * informs the line discipline if present that the driver is ready |
---|
1224 | * to receive more output data. |
---|
1225 | */ |
---|
1226 | |
---|
1227 | void tty_wakeup(struct tty_struct *tty) |
---|
1228 | { |
---|
1229 | struct tty_ldisc *ld; |
---|
1230 | |
---|
1231 | if (test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) { |
---|
1232 | ld = tty_ldisc_ref(tty); |
---|
1233 | if(ld) { |
---|
1234 | if(ld->write_wakeup) |
---|
1235 | ld->write_wakeup(tty); |
---|
1236 | tty_ldisc_deref(ld); |
---|
1237 | } |
---|
1238 | } |
---|
1239 | wake_up_interruptible(&tty->write_wait); |
---|
1240 | } |
---|
1241 | |
---|
1242 | EXPORT_SYMBOL_GPL(tty_wakeup); |
---|
1243 | |
---|
1244 | /** |
---|
1245 | * tty_ldisc_flush - flush line discipline queue |
---|
1246 | * @tty: tty |
---|
1247 | * |
---|
1248 | * Flush the line discipline queue (if any) for this tty. If there |
---|
1249 | * is no line discipline active this is a no-op. |
---|
1250 | */ |
---|
1251 | |
---|
1252 | void tty_ldisc_flush(struct tty_struct *tty) |
---|
1253 | { |
---|
1254 | struct tty_ldisc *ld = tty_ldisc_ref(tty); |
---|
1255 | if(ld) { |
---|
1256 | if(ld->flush_buffer) |
---|
1257 | ld->flush_buffer(tty); |
---|
1258 | tty_ldisc_deref(ld); |
---|
1259 | } |
---|
1260 | } |
---|
1261 | |
---|
1262 | EXPORT_SYMBOL_GPL(tty_ldisc_flush); |
---|
1263 | |
---|
1264 | /** |
---|
1265 | * do_tty_hangup - actual handler for hangup events |
---|
1266 | * @data: tty device |
---|
1267 | * |
---|
1268 | * This can be called by the "eventd" kernel thread. That is process |
---|
1269 | * synchronous but doesn't hold any locks, so we need to make sure we |
---|
1270 | * have the appropriate locks for what we're doing. |
---|
1271 | * |
---|
1272 | * The hangup event clears any pending redirections onto the hung up |
---|
1273 | * device. It ensures future writes will error and it does the needed |
---|
1274 | * line discipline hangup and signal delivery. The tty object itself |
---|
1275 | * remains intact. |
---|
1276 | * |
---|
1277 | * Locking: |
---|
1278 | * BKL |
---|
1279 | * redirect lock for undoing redirection |
---|
1280 | * file list lock for manipulating list of ttys |
---|
1281 | * tty_ldisc_lock from called functions |
---|
1282 | * termios_sem resetting termios data |
---|
1283 | * tasklist_lock to walk task list for hangup event |
---|
1284 | * |
---|
1285 | */ |
---|
1286 | static void do_tty_hangup(void *data) |
---|
1287 | { |
---|
1288 | struct tty_struct *tty = (struct tty_struct *) data; |
---|
1289 | struct file * cons_filp = NULL; |
---|
1290 | struct file *filp, *f = NULL; |
---|
1291 | struct task_struct *p; |
---|
1292 | struct tty_ldisc *ld; |
---|
1293 | int closecount = 0, n; |
---|
1294 | |
---|
1295 | if (!tty) |
---|
1296 | return; |
---|
1297 | |
---|
1298 | /* inuse_filps is protected by the single kernel lock */ |
---|
1299 | lock_kernel(); |
---|
1300 | |
---|
1301 | spin_lock(&redirect_lock); |
---|
1302 | if (redirect && redirect->private_data == tty) { |
---|
1303 | f = redirect; |
---|
1304 | redirect = NULL; |
---|
1305 | } |
---|
1306 | spin_unlock(&redirect_lock); |
---|
1307 | |
---|
1308 | check_tty_count(tty, "do_tty_hangup"); |
---|
1309 | file_list_lock(); |
---|
1310 | /* This breaks for file handles being sent over AF_UNIX sockets ? */ |
---|
1311 | list_for_each_entry(filp, &tty->tty_files, f_u.fu_list) { |
---|
1312 | if (filp->f_op->write == redirected_tty_write) |
---|
1313 | cons_filp = filp; |
---|
1314 | if (filp->f_op->write != tty_write) |
---|
1315 | continue; |
---|
1316 | closecount++; |
---|
1317 | tty_fasync(-1, filp, 0); /* can't block */ |
---|
1318 | filp->f_op = &hung_up_tty_fops; |
---|
1319 | } |
---|
1320 | file_list_unlock(); |
---|
1321 | |
---|
1322 | /* FIXME! What are the locking issues here? This may me overdoing things.. |
---|
1323 | * this question is especially important now that we've removed the irqlock. */ |
---|
1324 | |
---|
1325 | ld = tty_ldisc_ref(tty); |
---|
1326 | if(ld != NULL) /* We may have no line discipline at this point */ |
---|
1327 | { |
---|
1328 | if (ld->flush_buffer) |
---|
1329 | ld->flush_buffer(tty); |
---|
1330 | if (tty->driver->flush_buffer) |
---|
1331 | tty->driver->flush_buffer(tty); |
---|
1332 | if ((test_bit(TTY_DO_WRITE_WAKEUP, &tty->flags)) && |
---|
1333 | ld->write_wakeup) |
---|
1334 | ld->write_wakeup(tty); |
---|
1335 | if (ld->hangup) |
---|
1336 | ld->hangup(tty); |
---|
1337 | } |
---|
1338 | |
---|
1339 | /* FIXME: Once we trust the LDISC code better we can wait here for |
---|
1340 | ldisc completion and fix the driver call race */ |
---|
1341 | |
---|
1342 | wake_up_interruptible(&tty->write_wait); |
---|
1343 | wake_up_interruptible(&tty->read_wait); |
---|
1344 | |
---|
1345 | /* |
---|
1346 | * Shutdown the current line discipline, and reset it to |
---|
1347 | * N_TTY. |
---|
1348 | */ |
---|
1349 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) |
---|
1350 | { |
---|
1351 | down(&tty->termios_sem); |
---|
1352 | *tty->termios = tty->driver->init_termios; |
---|
1353 | up(&tty->termios_sem); |
---|
1354 | } |
---|
1355 | |
---|
1356 | /* Defer ldisc switch */ |
---|
1357 | /* tty_deferred_ldisc_switch(N_TTY); |
---|
1358 | |
---|
1359 | This should get done automatically when the port closes and |
---|
1360 | tty_release is called */ |
---|
1361 | |
---|
1362 | read_lock(&tasklist_lock); |
---|
1363 | if (tty->session > 0) { |
---|
1364 | do_each_task_pid(tty->session, PIDTYPE_SID, p) { |
---|
1365 | if (p->signal->tty == tty) |
---|
1366 | p->signal->tty = NULL; |
---|
1367 | if (!p->signal->leader) |
---|
1368 | continue; |
---|
1369 | group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p); |
---|
1370 | group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p); |
---|
1371 | if (tty->pgrp > 0) |
---|
1372 | p->signal->tty_old_pgrp = tty->pgrp; |
---|
1373 | } while_each_task_pid(tty->session, PIDTYPE_SID, p); |
---|
1374 | } |
---|
1375 | read_unlock(&tasklist_lock); |
---|
1376 | |
---|
1377 | tty->flags = 0; |
---|
1378 | tty->session = 0; |
---|
1379 | tty->pgrp = -1; |
---|
1380 | tty->ctrl_status = 0; |
---|
1381 | /* |
---|
1382 | * If one of the devices matches a console pointer, we |
---|
1383 | * cannot just call hangup() because that will cause |
---|
1384 | * tty->count and state->count to go out of sync. |
---|
1385 | * So we just call close() the right number of times. |
---|
1386 | */ |
---|
1387 | if (cons_filp) { |
---|
1388 | if (tty->driver->close) |
---|
1389 | for (n = 0; n < closecount; n++) |
---|
1390 | tty->driver->close(tty, cons_filp); |
---|
1391 | } else if (tty->driver->hangup) |
---|
1392 | (tty->driver->hangup)(tty); |
---|
1393 | |
---|
1394 | /* We don't want to have driver/ldisc interactions beyond |
---|
1395 | the ones we did here. The driver layer expects no |
---|
1396 | calls after ->hangup() from the ldisc side. However we |
---|
1397 | can't yet guarantee all that */ |
---|
1398 | |
---|
1399 | set_bit(TTY_HUPPED, &tty->flags); |
---|
1400 | if (ld) { |
---|
1401 | tty_ldisc_enable(tty); |
---|
1402 | tty_ldisc_deref(ld); |
---|
1403 | } |
---|
1404 | unlock_kernel(); |
---|
1405 | if (f) |
---|
1406 | fput(f); |
---|
1407 | } |
---|
1408 | |
---|
1409 | /** |
---|
1410 | * tty_hangup - trigger a hangup event |
---|
1411 | * @tty: tty to hangup |
---|
1412 | * |
---|
1413 | * A carrier loss (virtual or otherwise) has occurred on this like |
---|
1414 | * schedule a hangup sequence to run after this event. |
---|
1415 | */ |
---|
1416 | |
---|
1417 | void tty_hangup(struct tty_struct * tty) |
---|
1418 | { |
---|
1419 | #ifdef TTY_DEBUG_HANGUP |
---|
1420 | char buf[64]; |
---|
1421 | |
---|
1422 | printk(KERN_DEBUG "%s hangup...\n", tty_name(tty, buf)); |
---|
1423 | #endif |
---|
1424 | schedule_work(&tty->hangup_work); |
---|
1425 | } |
---|
1426 | |
---|
1427 | EXPORT_SYMBOL(tty_hangup); |
---|
1428 | |
---|
1429 | /** |
---|
1430 | * tty_vhangup - process vhangup |
---|
1431 | * @tty: tty to hangup |
---|
1432 | * |
---|
1433 | * The user has asked via system call for the terminal to be hung up. |
---|
1434 | * We do this synchronously so that when the syscall returns the process |
---|
1435 | * is complete. That guarantee is neccessary for security reasons. |
---|
1436 | */ |
---|
1437 | |
---|
1438 | void tty_vhangup(struct tty_struct * tty) |
---|
1439 | { |
---|
1440 | #ifdef TTY_DEBUG_HANGUP |
---|
1441 | char buf[64]; |
---|
1442 | |
---|
1443 | printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf)); |
---|
1444 | #endif |
---|
1445 | do_tty_hangup((void *) tty); |
---|
1446 | } |
---|
1447 | EXPORT_SYMBOL(tty_vhangup); |
---|
1448 | |
---|
1449 | /** |
---|
1450 | * tty_hung_up_p - was tty hung up |
---|
1451 | * @filp: file pointer of tty |
---|
1452 | * |
---|
1453 | * Return true if the tty has been subject to a vhangup or a carrier |
---|
1454 | * loss |
---|
1455 | */ |
---|
1456 | |
---|
1457 | int tty_hung_up_p(struct file * filp) |
---|
1458 | { |
---|
1459 | return (filp->f_op == &hung_up_tty_fops); |
---|
1460 | } |
---|
1461 | |
---|
1462 | EXPORT_SYMBOL(tty_hung_up_p); |
---|
1463 | |
---|
1464 | /** |
---|
1465 | * disassociate_ctty - disconnect controlling tty |
---|
1466 | * @on_exit: true if exiting so need to "hang up" the session |
---|
1467 | * |
---|
1468 | * This function is typically called only by the session leader, when |
---|
1469 | * it wants to disassociate itself from its controlling tty. |
---|
1470 | * |
---|
1471 | * It performs the following functions: |
---|
1472 | * (1) Sends a SIGHUP and SIGCONT to the foreground process group |
---|
1473 | * (2) Clears the tty from being controlling the session |
---|
1474 | * (3) Clears the controlling tty for all processes in the |
---|
1475 | * session group. |
---|
1476 | * |
---|
1477 | * The argument on_exit is set to 1 if called when a process is |
---|
1478 | * exiting; it is 0 if called by the ioctl TIOCNOTTY. |
---|
1479 | * |
---|
1480 | * Locking: tty_mutex is taken to protect current->signal->tty |
---|
1481 | * BKL is taken for hysterical raisins |
---|
1482 | * Tasklist lock is taken (under tty_mutex) to walk process |
---|
1483 | * lists for the session. |
---|
1484 | */ |
---|
1485 | |
---|
1486 | void disassociate_ctty(int on_exit) |
---|
1487 | { |
---|
1488 | struct tty_struct *tty; |
---|
1489 | struct task_struct *p; |
---|
1490 | int tty_pgrp = -1; |
---|
1491 | |
---|
1492 | lock_kernel(); |
---|
1493 | |
---|
1494 | mutex_lock(&tty_mutex); |
---|
1495 | tty = current->signal->tty; |
---|
1496 | if (tty) { |
---|
1497 | tty_pgrp = tty->pgrp; |
---|
1498 | mutex_unlock(&tty_mutex); |
---|
1499 | if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) |
---|
1500 | tty_vhangup(tty); |
---|
1501 | } else { |
---|
1502 | if (current->signal->tty_old_pgrp) { |
---|
1503 | kill_pg(current->signal->tty_old_pgrp, SIGHUP, on_exit); |
---|
1504 | kill_pg(current->signal->tty_old_pgrp, SIGCONT, on_exit); |
---|
1505 | } |
---|
1506 | mutex_unlock(&tty_mutex); |
---|
1507 | unlock_kernel(); |
---|
1508 | return; |
---|
1509 | } |
---|
1510 | if (tty_pgrp > 0) { |
---|
1511 | kill_pg(tty_pgrp, SIGHUP, on_exit); |
---|
1512 | if (!on_exit) |
---|
1513 | kill_pg(tty_pgrp, SIGCONT, on_exit); |
---|
1514 | } |
---|
1515 | |
---|
1516 | /* Must lock changes to tty_old_pgrp */ |
---|
1517 | mutex_lock(&tty_mutex); |
---|
1518 | current->signal->tty_old_pgrp = 0; |
---|
1519 | tty->session = 0; |
---|
1520 | tty->pgrp = -1; |
---|
1521 | |
---|
1522 | /* Now clear signal->tty under the lock */ |
---|
1523 | read_lock(&tasklist_lock); |
---|
1524 | do_each_task_pid(current->signal->session, PIDTYPE_SID, p) { |
---|
1525 | p->signal->tty = NULL; |
---|
1526 | } while_each_task_pid(current->signal->session, PIDTYPE_SID, p); |
---|
1527 | read_unlock(&tasklist_lock); |
---|
1528 | mutex_unlock(&tty_mutex); |
---|
1529 | unlock_kernel(); |
---|
1530 | } |
---|
1531 | |
---|
1532 | |
---|
1533 | /** |
---|
1534 | * stop_tty - propogate flow control |
---|
1535 | * @tty: tty to stop |
---|
1536 | * |
---|
1537 | * Perform flow control to the driver. For PTY/TTY pairs we |
---|
1538 | * must also propogate the TIOCKPKT status. May be called |
---|
1539 | * on an already stopped device and will not re-call the driver |
---|
1540 | * method. |
---|
1541 | * |
---|
1542 | * This functionality is used by both the line disciplines for |
---|
1543 | * halting incoming flow and by the driver. It may therefore be |
---|
1544 | * called from any context, may be under the tty atomic_write_lock |
---|
1545 | * but not always. |
---|
1546 | * |
---|
1547 | * Locking: |
---|
1548 | * Broken. Relies on BKL which is unsafe here. |
---|
1549 | */ |
---|
1550 | |
---|
1551 | void stop_tty(struct tty_struct *tty) |
---|
1552 | { |
---|
1553 | if (tty->stopped) |
---|
1554 | return; |
---|
1555 | tty->stopped = 1; |
---|
1556 | if (tty->link && tty->link->packet) { |
---|
1557 | tty->ctrl_status &= ~TIOCPKT_START; |
---|
1558 | tty->ctrl_status |= TIOCPKT_STOP; |
---|
1559 | wake_up_interruptible(&tty->link->read_wait); |
---|
1560 | } |
---|
1561 | if (tty->driver->stop) |
---|
1562 | (tty->driver->stop)(tty); |
---|
1563 | } |
---|
1564 | |
---|
1565 | EXPORT_SYMBOL(stop_tty); |
---|
1566 | |
---|
1567 | /** |
---|
1568 | * start_tty - propogate flow control |
---|
1569 | * @tty: tty to start |
---|
1570 | * |
---|
1571 | * Start a tty that has been stopped if at all possible. Perform |
---|
1572 | * any neccessary wakeups and propogate the TIOCPKT status. If this |
---|
1573 | * is the tty was previous stopped and is being started then the |
---|
1574 | * driver start method is invoked and the line discipline woken. |
---|
1575 | * |
---|
1576 | * Locking: |
---|
1577 | * Broken. Relies on BKL which is unsafe here. |
---|
1578 | */ |
---|
1579 | |
---|
1580 | void start_tty(struct tty_struct *tty) |
---|
1581 | { |
---|
1582 | if (!tty->stopped || tty->flow_stopped) |
---|
1583 | return; |
---|
1584 | tty->stopped = 0; |
---|
1585 | if (tty->link && tty->link->packet) { |
---|
1586 | tty->ctrl_status &= ~TIOCPKT_STOP; |
---|
1587 | tty->ctrl_status |= TIOCPKT_START; |
---|
1588 | wake_up_interruptible(&tty->link->read_wait); |
---|
1589 | } |
---|
1590 | if (tty->driver->start) |
---|
1591 | (tty->driver->start)(tty); |
---|
1592 | |
---|
1593 | /* If we have a running line discipline it may need kicking */ |
---|
1594 | tty_wakeup(tty); |
---|
1595 | wake_up_interruptible(&tty->write_wait); |
---|
1596 | } |
---|
1597 | |
---|
1598 | EXPORT_SYMBOL(start_tty); |
---|
1599 | |
---|
1600 | /** |
---|
1601 | * tty_read - read method for tty device files |
---|
1602 | * @file: pointer to tty file |
---|
1603 | * @buf: user buffer |
---|
1604 | * @count: size of user buffer |
---|
1605 | * @ppos: unused |
---|
1606 | * |
---|
1607 | * Perform the read system call function on this terminal device. Checks |
---|
1608 | * for hung up devices before calling the line discipline method. |
---|
1609 | * |
---|
1610 | * Locking: |
---|
1611 | * Locks the line discipline internally while needed |
---|
1612 | * For historical reasons the line discipline read method is |
---|
1613 | * invoked under the BKL. This will go away in time so do not rely on it |
---|
1614 | * in new code. Multiple read calls may be outstanding in parallel. |
---|
1615 | */ |
---|
1616 | |
---|
1617 | static ssize_t tty_read(struct file * file, char __user * buf, size_t count, |
---|
1618 | loff_t *ppos) |
---|
1619 | { |
---|
1620 | int i; |
---|
1621 | struct tty_struct * tty; |
---|
1622 | struct inode *inode; |
---|
1623 | struct tty_ldisc *ld; |
---|
1624 | |
---|
1625 | tty = (struct tty_struct *)file->private_data; |
---|
1626 | inode = file->f_dentry->d_inode; |
---|
1627 | if (tty_paranoia_check(tty, inode, "tty_read")) |
---|
1628 | return -EIO; |
---|
1629 | if (!tty || (test_bit(TTY_IO_ERROR, &tty->flags))) |
---|
1630 | return -EIO; |
---|
1631 | |
---|
1632 | /* We want to wait for the line discipline to sort out in this |
---|
1633 | situation */ |
---|
1634 | ld = tty_ldisc_ref_wait(tty); |
---|
1635 | lock_kernel(); |
---|
1636 | if (ld->read) |
---|
1637 | i = (ld->read)(tty,file,buf,count); |
---|
1638 | else |
---|
1639 | i = -EIO; |
---|
1640 | tty_ldisc_deref(ld); |
---|
1641 | unlock_kernel(); |
---|
1642 | if (i > 0) |
---|
1643 | inode->i_atime = current_fs_time(inode->i_sb); |
---|
1644 | return i; |
---|
1645 | } |
---|
1646 | |
---|
1647 | /* |
---|
1648 | * Split writes up in sane blocksizes to avoid |
---|
1649 | * denial-of-service type attacks |
---|
1650 | */ |
---|
1651 | static inline ssize_t do_tty_write( |
---|
1652 | ssize_t (*write)(struct tty_struct *, struct file *, const unsigned char *, size_t), |
---|
1653 | struct tty_struct *tty, |
---|
1654 | struct file *file, |
---|
1655 | const char __user *buf, |
---|
1656 | size_t count) |
---|
1657 | { |
---|
1658 | ssize_t ret = 0, written = 0; |
---|
1659 | unsigned int chunk; |
---|
1660 | |
---|
1661 | /* FIXME: O_NDELAY ... */ |
---|
1662 | if (mutex_lock_interruptible(&tty->atomic_write_lock)) { |
---|
1663 | return -ERESTARTSYS; |
---|
1664 | } |
---|
1665 | |
---|
1666 | /* |
---|
1667 | * We chunk up writes into a temporary buffer. This |
---|
1668 | * simplifies low-level drivers immensely, since they |
---|
1669 | * don't have locking issues and user mode accesses. |
---|
1670 | * |
---|
1671 | * But if TTY_NO_WRITE_SPLIT is set, we should use a |
---|
1672 | * big chunk-size.. |
---|
1673 | * |
---|
1674 | * The default chunk-size is 2kB, because the NTTY |
---|
1675 | * layer has problems with bigger chunks. It will |
---|
1676 | * claim to be able to handle more characters than |
---|
1677 | * it actually does. |
---|
1678 | * |
---|
1679 | * FIXME: This can probably go away now except that 64K chunks |
---|
1680 | * are too likely to fail unless switched to vmalloc... |
---|
1681 | */ |
---|
1682 | chunk = 2048; |
---|
1683 | if (test_bit(TTY_NO_WRITE_SPLIT, &tty->flags)) |
---|
1684 | chunk = 65536; |
---|
1685 | if (count < chunk) |
---|
1686 | chunk = count; |
---|
1687 | |
---|
1688 | /* write_buf/write_cnt is protected by the atomic_write_lock mutex */ |
---|
1689 | if (tty->write_cnt < chunk) { |
---|
1690 | unsigned char *buf; |
---|
1691 | |
---|
1692 | if (chunk < 1024) |
---|
1693 | chunk = 1024; |
---|
1694 | |
---|
1695 | buf = kmalloc(chunk, GFP_KERNEL); |
---|
1696 | if (!buf) { |
---|
1697 | mutex_unlock(&tty->atomic_write_lock); |
---|
1698 | return -ENOMEM; |
---|
1699 | } |
---|
1700 | kfree(tty->write_buf); |
---|
1701 | tty->write_cnt = chunk; |
---|
1702 | tty->write_buf = buf; |
---|
1703 | } |
---|
1704 | |
---|
1705 | /* Do the write .. */ |
---|
1706 | for (;;) { |
---|
1707 | size_t size = count; |
---|
1708 | if (size > chunk) |
---|
1709 | size = chunk; |
---|
1710 | ret = -EFAULT; |
---|
1711 | if (copy_from_user(tty->write_buf, buf, size)) |
---|
1712 | break; |
---|
1713 | lock_kernel(); |
---|
1714 | ret = write(tty, file, tty->write_buf, size); |
---|
1715 | unlock_kernel(); |
---|
1716 | if (ret <= 0) |
---|
1717 | break; |
---|
1718 | written += ret; |
---|
1719 | buf += ret; |
---|
1720 | count -= ret; |
---|
1721 | if (!count) |
---|
1722 | break; |
---|
1723 | ret = -ERESTARTSYS; |
---|
1724 | if (signal_pending(current)) |
---|
1725 | break; |
---|
1726 | cond_resched(); |
---|
1727 | } |
---|
1728 | if (written) { |
---|
1729 | struct inode *inode = file->f_dentry->d_inode; |
---|
1730 | inode->i_mtime = current_fs_time(inode->i_sb); |
---|
1731 | ret = written; |
---|
1732 | } |
---|
1733 | mutex_unlock(&tty->atomic_write_lock); |
---|
1734 | return ret; |
---|
1735 | } |
---|
1736 | |
---|
1737 | |
---|
1738 | /** |
---|
1739 | * tty_write - write method for tty device file |
---|
1740 | * @file: tty file pointer |
---|
1741 | * @buf: user data to write |
---|
1742 | * @count: bytes to write |
---|
1743 | * @ppos: unused |
---|
1744 | * |
---|
1745 | * Write data to a tty device via the line discipline. |
---|
1746 | * |
---|
1747 | * Locking: |
---|
1748 | * Locks the line discipline as required |
---|
1749 | * Writes to the tty driver are serialized by the atomic_write_lock |
---|
1750 | * and are then processed in chunks to the device. The line discipline |
---|
1751 | * write method will not be involked in parallel for each device |
---|
1752 | * The line discipline write method is called under the big |
---|
1753 | * kernel lock for historical reasons. New code should not rely on this. |
---|
1754 | */ |
---|
1755 | |
---|
1756 | static ssize_t tty_write(struct file * file, const char __user * buf, size_t count, |
---|
1757 | loff_t *ppos) |
---|
1758 | { |
---|
1759 | struct tty_struct * tty; |
---|
1760 | struct inode *inode = file->f_dentry->d_inode; |
---|
1761 | ssize_t ret; |
---|
1762 | struct tty_ldisc *ld; |
---|
1763 | |
---|
1764 | tty = (struct tty_struct *)file->private_data; |
---|
1765 | if (tty_paranoia_check(tty, inode, "tty_write")) |
---|
1766 | return -EIO; |
---|
1767 | if (!tty || !tty->driver->write || (test_bit(TTY_IO_ERROR, &tty->flags))) |
---|
1768 | return -EIO; |
---|
1769 | |
---|
1770 | ld = tty_ldisc_ref_wait(tty); |
---|
1771 | if (!ld->write) |
---|
1772 | ret = -EIO; |
---|
1773 | else |
---|
1774 | ret = do_tty_write(ld->write, tty, file, buf, count); |
---|
1775 | tty_ldisc_deref(ld); |
---|
1776 | return ret; |
---|
1777 | } |
---|
1778 | |
---|
1779 | ssize_t redirected_tty_write(struct file * file, const char __user * buf, size_t count, |
---|
1780 | loff_t *ppos) |
---|
1781 | { |
---|
1782 | struct file *p = NULL; |
---|
1783 | |
---|
1784 | spin_lock(&redirect_lock); |
---|
1785 | if (redirect) { |
---|
1786 | get_file(redirect); |
---|
1787 | p = redirect; |
---|
1788 | } |
---|
1789 | spin_unlock(&redirect_lock); |
---|
1790 | |
---|
1791 | if (p) { |
---|
1792 | ssize_t res; |
---|
1793 | res = vfs_write(p, buf, count, &p->f_pos); |
---|
1794 | fput(p); |
---|
1795 | return res; |
---|
1796 | } |
---|
1797 | |
---|
1798 | return tty_write(file, buf, count, ppos); |
---|
1799 | } |
---|
1800 | |
---|
1801 | static char ptychar[] = "pqrstuvwxyzabcde"; |
---|
1802 | |
---|
1803 | /** |
---|
1804 | * pty_line_name - generate name for a pty |
---|
1805 | * @driver: the tty driver in use |
---|
1806 | * @index: the minor number |
---|
1807 | * @p: output buffer of at least 6 bytes |
---|
1808 | * |
---|
1809 | * Generate a name from a driver reference and write it to the output |
---|
1810 | * buffer. |
---|
1811 | * |
---|
1812 | * Locking: None |
---|
1813 | */ |
---|
1814 | static void pty_line_name(struct tty_driver *driver, int index, char *p) |
---|
1815 | { |
---|
1816 | int i = index + driver->name_base; |
---|
1817 | /* ->name is initialized to "ttyp", but "tty" is expected */ |
---|
1818 | sprintf(p, "%s%c%x", |
---|
1819 | driver->subtype == PTY_TYPE_SLAVE ? "tty" : driver->name, |
---|
1820 | ptychar[i >> 4 & 0xf], i & 0xf); |
---|
1821 | } |
---|
1822 | |
---|
1823 | /** |
---|
1824 | * pty_line_name - generate name for a tty |
---|
1825 | * @driver: the tty driver in use |
---|
1826 | * @index: the minor number |
---|
1827 | * @p: output buffer of at least 7 bytes |
---|
1828 | * |
---|
1829 | * Generate a name from a driver reference and write it to the output |
---|
1830 | * buffer. |
---|
1831 | * |
---|
1832 | * Locking: None |
---|
1833 | */ |
---|
1834 | static void tty_line_name(struct tty_driver *driver, int index, char *p) |
---|
1835 | { |
---|
1836 | sprintf(p, "%s%d", driver->name, index + driver->name_base); |
---|
1837 | } |
---|
1838 | |
---|
1839 | /** |
---|
1840 | * init_dev - initialise a tty device |
---|
1841 | * @driver: tty driver we are opening a device on |
---|
1842 | * @idx: device index |
---|
1843 | * @tty: returned tty structure |
---|
1844 | * |
---|
1845 | * Prepare a tty device. This may not be a "new" clean device but |
---|
1846 | * could also be an active device. The pty drivers require special |
---|
1847 | * handling because of this. |
---|
1848 | * |
---|
1849 | * Locking: |
---|
1850 | * The function is called under the tty_mutex, which |
---|
1851 | * protects us from the tty struct or driver itself going away. |
---|
1852 | * |
---|
1853 | * On exit the tty device has the line discipline attached and |
---|
1854 | * a reference count of 1. If a pair was created for pty/tty use |
---|
1855 | * and the other was a pty master then it too has a reference count of 1. |
---|
1856 | * |
---|
1857 | * WSH 06/09/97: Rewritten to remove races and properly clean up after a |
---|
1858 | * failed open. The new code protects the open with a mutex, so it's |
---|
1859 | * really quite straightforward. The mutex locking can probably be |
---|
1860 | * relaxed for the (most common) case of reopening a tty. |
---|
1861 | */ |
---|
1862 | |
---|
1863 | static int init_dev(struct tty_driver *driver, int idx, |
---|
1864 | struct tty_struct **ret_tty) |
---|
1865 | { |
---|
1866 | struct tty_struct *tty, *o_tty; |
---|
1867 | struct termios *tp, **tp_loc, *o_tp, **o_tp_loc; |
---|
1868 | struct termios *ltp, **ltp_loc, *o_ltp, **o_ltp_loc; |
---|
1869 | int retval = 0; |
---|
1870 | |
---|
1871 | /* check whether we're reopening an existing tty */ |
---|
1872 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { |
---|
1873 | tty = devpts_get_tty(idx); |
---|
1874 | if (tty && driver->subtype == PTY_TYPE_MASTER) |
---|
1875 | tty = tty->link; |
---|
1876 | } else { |
---|
1877 | tty = driver->ttys[idx]; |
---|
1878 | } |
---|
1879 | if (tty) goto fast_track; |
---|
1880 | |
---|
1881 | /* |
---|
1882 | * First time open is complex, especially for PTY devices. |
---|
1883 | * This code guarantees that either everything succeeds and the |
---|
1884 | * TTY is ready for operation, or else the table slots are vacated |
---|
1885 | * and the allocated memory released. (Except that the termios |
---|
1886 | * and locked termios may be retained.) |
---|
1887 | */ |
---|
1888 | |
---|
1889 | if (!try_module_get(driver->owner)) { |
---|
1890 | retval = -ENODEV; |
---|
1891 | goto end_init; |
---|
1892 | } |
---|
1893 | |
---|
1894 | o_tty = NULL; |
---|
1895 | tp = o_tp = NULL; |
---|
1896 | ltp = o_ltp = NULL; |
---|
1897 | |
---|
1898 | tty = alloc_tty_struct(); |
---|
1899 | if(!tty) |
---|
1900 | goto fail_no_mem; |
---|
1901 | initialize_tty_struct(tty); |
---|
1902 | tty->driver = driver; |
---|
1903 | tty->index = idx; |
---|
1904 | tty_line_name(driver, idx, tty->name); |
---|
1905 | |
---|
1906 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { |
---|
1907 | tp_loc = &tty->termios; |
---|
1908 | ltp_loc = &tty->termios_locked; |
---|
1909 | } else { |
---|
1910 | tp_loc = &driver->termios[idx]; |
---|
1911 | ltp_loc = &driver->termios_locked[idx]; |
---|
1912 | } |
---|
1913 | |
---|
1914 | if (!*tp_loc) { |
---|
1915 | tp = (struct termios *) kmalloc(sizeof(struct termios), |
---|
1916 | GFP_KERNEL); |
---|
1917 | if (!tp) |
---|
1918 | goto free_mem_out; |
---|
1919 | *tp = driver->init_termios; |
---|
1920 | } |
---|
1921 | |
---|
1922 | if (!*ltp_loc) { |
---|
1923 | ltp = (struct termios *) kmalloc(sizeof(struct termios), |
---|
1924 | GFP_KERNEL); |
---|
1925 | if (!ltp) |
---|
1926 | goto free_mem_out; |
---|
1927 | memset(ltp, 0, sizeof(struct termios)); |
---|
1928 | } |
---|
1929 | |
---|
1930 | if (driver->type == TTY_DRIVER_TYPE_PTY) { |
---|
1931 | o_tty = alloc_tty_struct(); |
---|
1932 | if (!o_tty) |
---|
1933 | goto free_mem_out; |
---|
1934 | initialize_tty_struct(o_tty); |
---|
1935 | o_tty->driver = driver->other; |
---|
1936 | o_tty->index = idx; |
---|
1937 | tty_line_name(driver->other, idx, o_tty->name); |
---|
1938 | |
---|
1939 | if (driver->flags & TTY_DRIVER_DEVPTS_MEM) { |
---|
1940 | o_tp_loc = &o_tty->termios; |
---|
1941 | o_ltp_loc = &o_tty->termios_locked; |
---|
1942 | } else { |
---|
1943 | o_tp_loc = &driver->other->termios[idx]; |
---|
1944 | o_ltp_loc = &driver->other->termios_locked[idx]; |
---|
1945 | } |
---|
1946 | |
---|
1947 | if (!*o_tp_loc) { |
---|
1948 | o_tp = (struct termios *) |
---|
1949 | kmalloc(sizeof(struct termios), GFP_KERNEL); |
---|
1950 | if (!o_tp) |
---|
1951 | goto free_mem_out; |
---|
1952 | *o_tp = driver->other->init_termios; |
---|
1953 | } |
---|
1954 | |
---|
1955 | if (!*o_ltp_loc) { |
---|
1956 | o_ltp = (struct termios *) |
---|
1957 | kmalloc(sizeof(struct termios), GFP_KERNEL); |
---|
1958 | if (!o_ltp) |
---|
1959 | goto free_mem_out; |
---|
1960 | memset(o_ltp, 0, sizeof(struct termios)); |
---|
1961 | } |
---|
1962 | |
---|
1963 | /* |
---|
1964 | * Everything allocated ... set up the o_tty structure. |
---|
1965 | */ |
---|
1966 | if (!(driver->other->flags & TTY_DRIVER_DEVPTS_MEM)) { |
---|
1967 | driver->other->ttys[idx] = o_tty; |
---|
1968 | } |
---|
1969 | if (!*o_tp_loc) |
---|
1970 | *o_tp_loc = o_tp; |
---|
1971 | if (!*o_ltp_loc) |
---|
1972 | *o_ltp_loc = o_ltp; |
---|
1973 | o_tty->termios = *o_tp_loc; |
---|
1974 | o_tty->termios_locked = *o_ltp_loc; |
---|
1975 | driver->other->refcount++; |
---|
1976 | if (driver->subtype == PTY_TYPE_MASTER) |
---|
1977 | o_tty->count++; |
---|
1978 | |
---|
1979 | /* Establish the links in both directions */ |
---|
1980 | tty->link = o_tty; |
---|
1981 | o_tty->link = tty; |
---|
1982 | } |
---|
1983 | |
---|
1984 | /* |
---|
1985 | * All structures have been allocated, so now we install them. |
---|
1986 | * Failures after this point use release_mem to clean up, so |
---|
1987 | * there's no need to null out the local pointers. |
---|
1988 | */ |
---|
1989 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { |
---|
1990 | driver->ttys[idx] = tty; |
---|
1991 | } |
---|
1992 | |
---|
1993 | if (!*tp_loc) |
---|
1994 | *tp_loc = tp; |
---|
1995 | if (!*ltp_loc) |
---|
1996 | *ltp_loc = ltp; |
---|
1997 | tty->termios = *tp_loc; |
---|
1998 | tty->termios_locked = *ltp_loc; |
---|
1999 | driver->refcount++; |
---|
2000 | tty->count++; |
---|
2001 | |
---|
2002 | /* |
---|
2003 | * Structures all installed ... call the ldisc open routines. |
---|
2004 | * If we fail here just call release_mem to clean up. No need |
---|
2005 | * to decrement the use counts, as release_mem doesn't care. |
---|
2006 | */ |
---|
2007 | |
---|
2008 | if (tty->ldisc.open) { |
---|
2009 | retval = (tty->ldisc.open)(tty); |
---|
2010 | if (retval) |
---|
2011 | goto release_mem_out; |
---|
2012 | } |
---|
2013 | if (o_tty && o_tty->ldisc.open) { |
---|
2014 | retval = (o_tty->ldisc.open)(o_tty); |
---|
2015 | if (retval) { |
---|
2016 | if (tty->ldisc.close) |
---|
2017 | (tty->ldisc.close)(tty); |
---|
2018 | goto release_mem_out; |
---|
2019 | } |
---|
2020 | tty_ldisc_enable(o_tty); |
---|
2021 | } |
---|
2022 | tty_ldisc_enable(tty); |
---|
2023 | goto success; |
---|
2024 | |
---|
2025 | /* |
---|
2026 | * This fast open can be used if the tty is already open. |
---|
2027 | * No memory is allocated, and the only failures are from |
---|
2028 | * attempting to open a closing tty or attempting multiple |
---|
2029 | * opens on a pty master. |
---|
2030 | */ |
---|
2031 | fast_track: |
---|
2032 | if (test_bit(TTY_CLOSING, &tty->flags)) { |
---|
2033 | retval = -EIO; |
---|
2034 | goto end_init; |
---|
2035 | } |
---|
2036 | if (driver->type == TTY_DRIVER_TYPE_PTY && |
---|
2037 | driver->subtype == PTY_TYPE_MASTER) { |
---|
2038 | /* |
---|
2039 | * special case for PTY masters: only one open permitted, |
---|
2040 | * and the slave side open count is incremented as well. |
---|
2041 | */ |
---|
2042 | if (tty->count) { |
---|
2043 | retval = -EIO; |
---|
2044 | goto end_init; |
---|
2045 | } |
---|
2046 | tty->link->count++; |
---|
2047 | } |
---|
2048 | tty->count++; |
---|
2049 | tty->driver = driver; /* N.B. why do this every time?? */ |
---|
2050 | |
---|
2051 | /* FIXME */ |
---|
2052 | if(!test_bit(TTY_LDISC, &tty->flags)) |
---|
2053 | printk(KERN_ERR "init_dev but no ldisc\n"); |
---|
2054 | success: |
---|
2055 | *ret_tty = tty; |
---|
2056 | |
---|
2057 | /* All paths come through here to release the mutex */ |
---|
2058 | end_init: |
---|
2059 | return retval; |
---|
2060 | |
---|
2061 | /* Release locally allocated memory ... nothing placed in slots */ |
---|
2062 | free_mem_out: |
---|
2063 | kfree(o_tp); |
---|
2064 | if (o_tty) |
---|
2065 | free_tty_struct(o_tty); |
---|
2066 | kfree(ltp); |
---|
2067 | kfree(tp); |
---|
2068 | free_tty_struct(tty); |
---|
2069 | |
---|
2070 | fail_no_mem: |
---|
2071 | module_put(driver->owner); |
---|
2072 | retval = -ENOMEM; |
---|
2073 | goto end_init; |
---|
2074 | |
---|
2075 | /* call the tty release_mem routine to clean out this slot */ |
---|
2076 | release_mem_out: |
---|
2077 | printk(KERN_INFO "init_dev: ldisc open failed, " |
---|
2078 | "clearing slot %d\n", idx); |
---|
2079 | release_mem(tty, idx); |
---|
2080 | goto end_init; |
---|
2081 | } |
---|
2082 | |
---|
2083 | /** |
---|
2084 | * release_mem - release tty structure memory |
---|
2085 | * |
---|
2086 | * Releases memory associated with a tty structure, and clears out the |
---|
2087 | * driver table slots. This function is called when a device is no longer |
---|
2088 | * in use. It also gets called when setup of a device fails. |
---|
2089 | * |
---|
2090 | * Locking: |
---|
2091 | * tty_mutex - sometimes only |
---|
2092 | * takes the file list lock internally when working on the list |
---|
2093 | * of ttys that the driver keeps. |
---|
2094 | * FIXME: should we require tty_mutex is held here ?? |
---|
2095 | */ |
---|
2096 | |
---|
2097 | static void release_mem(struct tty_struct *tty, int idx) |
---|
2098 | { |
---|
2099 | struct tty_struct *o_tty; |
---|
2100 | struct termios *tp; |
---|
2101 | int devpts = tty->driver->flags & TTY_DRIVER_DEVPTS_MEM; |
---|
2102 | |
---|
2103 | if ((o_tty = tty->link) != NULL) { |
---|
2104 | if (!devpts) |
---|
2105 | o_tty->driver->ttys[idx] = NULL; |
---|
2106 | if (o_tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
---|
2107 | tp = o_tty->termios; |
---|
2108 | if (!devpts) |
---|
2109 | o_tty->driver->termios[idx] = NULL; |
---|
2110 | kfree(tp); |
---|
2111 | |
---|
2112 | tp = o_tty->termios_locked; |
---|
2113 | if (!devpts) |
---|
2114 | o_tty->driver->termios_locked[idx] = NULL; |
---|
2115 | kfree(tp); |
---|
2116 | } |
---|
2117 | o_tty->magic = 0; |
---|
2118 | o_tty->driver->refcount--; |
---|
2119 | file_list_lock(); |
---|
2120 | list_del_init(&o_tty->tty_files); |
---|
2121 | file_list_unlock(); |
---|
2122 | free_tty_struct(o_tty); |
---|
2123 | } |
---|
2124 | |
---|
2125 | if (!devpts) |
---|
2126 | tty->driver->ttys[idx] = NULL; |
---|
2127 | if (tty->driver->flags & TTY_DRIVER_RESET_TERMIOS) { |
---|
2128 | tp = tty->termios; |
---|
2129 | if (!devpts) |
---|
2130 | tty->driver->termios[idx] = NULL; |
---|
2131 | kfree(tp); |
---|
2132 | |
---|
2133 | tp = tty->termios_locked; |
---|
2134 | if (!devpts) |
---|
2135 | tty->driver->termios_locked[idx] = NULL; |
---|
2136 | kfree(tp); |
---|
2137 | } |
---|
2138 | |
---|
2139 | tty->magic = 0; |
---|
2140 | tty->driver->refcount--; |
---|
2141 | file_list_lock(); |
---|
2142 | list_del_init(&tty->tty_files); |
---|
2143 | file_list_unlock(); |
---|
2144 | module_put(tty->driver->owner); |
---|
2145 | free_tty_struct(tty); |
---|
2146 | } |
---|
2147 | |
---|
2148 | /* |
---|
2149 | * Even releasing the tty structures is a tricky business.. We have |
---|
2150 | * to be very careful that the structures are all released at the |
---|
2151 | * same time, as interrupts might otherwise get the wrong pointers. |
---|
2152 | * |
---|
2153 | * WSH 09/09/97: rewritten to avoid some nasty race conditions that could |
---|
2154 | * lead to double frees or releasing memory still in use. |
---|
2155 | */ |
---|
2156 | static void release_dev(struct file * filp) |
---|
2157 | { |
---|
2158 | struct tty_struct *tty, *o_tty; |
---|
2159 | int pty_master, tty_closing, o_tty_closing, do_sleep; |
---|
2160 | int devpts; |
---|
2161 | int idx; |
---|
2162 | char buf[64]; |
---|
2163 | unsigned long flags; |
---|
2164 | |
---|
2165 | tty = (struct tty_struct *)filp->private_data; |
---|
2166 | if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "release_dev")) |
---|
2167 | return; |
---|
2168 | |
---|
2169 | check_tty_count(tty, "release_dev"); |
---|
2170 | |
---|
2171 | tty_fasync(-1, filp, 0); |
---|
2172 | |
---|
2173 | idx = tty->index; |
---|
2174 | pty_master = (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
---|
2175 | tty->driver->subtype == PTY_TYPE_MASTER); |
---|
2176 | devpts = (tty->driver->flags & TTY_DRIVER_DEVPTS_MEM) != 0; |
---|
2177 | o_tty = tty->link; |
---|
2178 | |
---|
2179 | #ifdef TTY_PARANOIA_CHECK |
---|
2180 | if (idx < 0 || idx >= tty->driver->num) { |
---|
2181 | printk(KERN_DEBUG "release_dev: bad idx when trying to " |
---|
2182 | "free (%s)\n", tty->name); |
---|
2183 | return; |
---|
2184 | } |
---|
2185 | if (!(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { |
---|
2186 | if (tty != tty->driver->ttys[idx]) { |
---|
2187 | printk(KERN_DEBUG "release_dev: driver.table[%d] not tty " |
---|
2188 | "for (%s)\n", idx, tty->name); |
---|
2189 | return; |
---|
2190 | } |
---|
2191 | if (tty->termios != tty->driver->termios[idx]) { |
---|
2192 | printk(KERN_DEBUG "release_dev: driver.termios[%d] not termios " |
---|
2193 | "for (%s)\n", |
---|
2194 | idx, tty->name); |
---|
2195 | return; |
---|
2196 | } |
---|
2197 | if (tty->termios_locked != tty->driver->termios_locked[idx]) { |
---|
2198 | printk(KERN_DEBUG "release_dev: driver.termios_locked[%d] not " |
---|
2199 | "termios_locked for (%s)\n", |
---|
2200 | idx, tty->name); |
---|
2201 | return; |
---|
2202 | } |
---|
2203 | } |
---|
2204 | #endif |
---|
2205 | |
---|
2206 | #ifdef TTY_DEBUG_HANGUP |
---|
2207 | printk(KERN_DEBUG "release_dev of %s (tty count=%d)...", |
---|
2208 | tty_name(tty, buf), tty->count); |
---|
2209 | #endif |
---|
2210 | |
---|
2211 | #ifdef TTY_PARANOIA_CHECK |
---|
2212 | if (tty->driver->other && |
---|
2213 | !(tty->driver->flags & TTY_DRIVER_DEVPTS_MEM)) { |
---|
2214 | if (o_tty != tty->driver->other->ttys[idx]) { |
---|
2215 | printk(KERN_DEBUG "release_dev: other->table[%d] " |
---|
2216 | "not o_tty for (%s)\n", |
---|
2217 | idx, tty->name); |
---|
2218 | return; |
---|
2219 | } |
---|
2220 | if (o_tty->termios != tty->driver->other->termios[idx]) { |
---|
2221 | printk(KERN_DEBUG "release_dev: other->termios[%d] " |
---|
2222 | "not o_termios for (%s)\n", |
---|
2223 | idx, tty->name); |
---|
2224 | return; |
---|
2225 | } |
---|
2226 | if (o_tty->termios_locked != |
---|
2227 | tty->driver->other->termios_locked[idx]) { |
---|
2228 | printk(KERN_DEBUG "release_dev: other->termios_locked[" |
---|
2229 | "%d] not o_termios_locked for (%s)\n", |
---|
2230 | idx, tty->name); |
---|
2231 | return; |
---|
2232 | } |
---|
2233 | if (o_tty->link != tty) { |
---|
2234 | printk(KERN_DEBUG "release_dev: bad pty pointers\n"); |
---|
2235 | return; |
---|
2236 | } |
---|
2237 | } |
---|
2238 | #endif |
---|
2239 | if (tty->driver->close) |
---|
2240 | tty->driver->close(tty, filp); |
---|
2241 | |
---|
2242 | /* |
---|
2243 | * Sanity check: if tty->count is going to zero, there shouldn't be |
---|
2244 | * any waiters on tty->read_wait or tty->write_wait. We test the |
---|
2245 | * wait queues and kick everyone out _before_ actually starting to |
---|
2246 | * close. This ensures that we won't block while releasing the tty |
---|
2247 | * structure. |
---|
2248 | * |
---|
2249 | * The test for the o_tty closing is necessary, since the master and |
---|
2250 | * slave sides may close in any order. If the slave side closes out |
---|
2251 | * first, its count will be one, since the master side holds an open. |
---|
2252 | * Thus this test wouldn't be triggered at the time the slave closes, |
---|
2253 | * so we do it now. |
---|
2254 | * |
---|
2255 | * Note that it's possible for the tty to be opened again while we're |
---|
2256 | * flushing out waiters. By recalculating the closing flags before |
---|
2257 | * each iteration we avoid any problems. |
---|
2258 | */ |
---|
2259 | while (1) { |
---|
2260 | /* Guard against races with tty->count changes elsewhere and |
---|
2261 | opens on /dev/tty */ |
---|
2262 | |
---|
2263 | mutex_lock(&tty_mutex); |
---|
2264 | tty_closing = tty->count <= 1; |
---|
2265 | o_tty_closing = o_tty && |
---|
2266 | (o_tty->count <= (pty_master ? 1 : 0)); |
---|
2267 | do_sleep = 0; |
---|
2268 | |
---|
2269 | if (tty_closing) { |
---|
2270 | if (waitqueue_active(&tty->read_wait)) { |
---|
2271 | wake_up(&tty->read_wait); |
---|
2272 | do_sleep++; |
---|
2273 | } |
---|
2274 | if (waitqueue_active(&tty->write_wait)) { |
---|
2275 | wake_up(&tty->write_wait); |
---|
2276 | do_sleep++; |
---|
2277 | } |
---|
2278 | } |
---|
2279 | if (o_tty_closing) { |
---|
2280 | if (waitqueue_active(&o_tty->read_wait)) { |
---|
2281 | wake_up(&o_tty->read_wait); |
---|
2282 | do_sleep++; |
---|
2283 | } |
---|
2284 | if (waitqueue_active(&o_tty->write_wait)) { |
---|
2285 | wake_up(&o_tty->write_wait); |
---|
2286 | do_sleep++; |
---|
2287 | } |
---|
2288 | } |
---|
2289 | if (!do_sleep) |
---|
2290 | break; |
---|
2291 | |
---|
2292 | printk(KERN_WARNING "release_dev: %s: read/write wait queue " |
---|
2293 | "active!\n", tty_name(tty, buf)); |
---|
2294 | mutex_unlock(&tty_mutex); |
---|
2295 | schedule(); |
---|
2296 | } |
---|
2297 | |
---|
2298 | /* |
---|
2299 | * The closing flags are now consistent with the open counts on |
---|
2300 | * both sides, and we've completed the last operation that could |
---|
2301 | * block, so it's safe to proceed with closing. |
---|
2302 | */ |
---|
2303 | if (pty_master) { |
---|
2304 | if (--o_tty->count < 0) { |
---|
2305 | printk(KERN_WARNING "release_dev: bad pty slave count " |
---|
2306 | "(%d) for %s\n", |
---|
2307 | o_tty->count, tty_name(o_tty, buf)); |
---|
2308 | o_tty->count = 0; |
---|
2309 | } |
---|
2310 | } |
---|
2311 | if (--tty->count < 0) { |
---|
2312 | printk(KERN_WARNING "release_dev: bad tty->count (%d) for %s\n", |
---|
2313 | tty->count, tty_name(tty, buf)); |
---|
2314 | tty->count = 0; |
---|
2315 | } |
---|
2316 | |
---|
2317 | /* |
---|
2318 | * We've decremented tty->count, so we need to remove this file |
---|
2319 | * descriptor off the tty->tty_files list; this serves two |
---|
2320 | * purposes: |
---|
2321 | * - check_tty_count sees the correct number of file descriptors |
---|
2322 | * associated with this tty. |
---|
2323 | * - do_tty_hangup no longer sees this file descriptor as |
---|
2324 | * something that needs to be handled for hangups. |
---|
2325 | */ |
---|
2326 | file_kill(filp); |
---|
2327 | filp->private_data = NULL; |
---|
2328 | |
---|
2329 | /* |
---|
2330 | * Perform some housekeeping before deciding whether to return. |
---|
2331 | * |
---|
2332 | * Set the TTY_CLOSING flag if this was the last open. In the |
---|
2333 | * case of a pty we may have to wait around for the other side |
---|
2334 | * to close, and TTY_CLOSING makes sure we can't be reopened. |
---|
2335 | */ |
---|
2336 | if(tty_closing) |
---|
2337 | set_bit(TTY_CLOSING, &tty->flags); |
---|
2338 | if(o_tty_closing) |
---|
2339 | set_bit(TTY_CLOSING, &o_tty->flags); |
---|
2340 | |
---|
2341 | /* |
---|
2342 | * If _either_ side is closing, make sure there aren't any |
---|
2343 | * processes that still think tty or o_tty is their controlling |
---|
2344 | * tty. |
---|
2345 | */ |
---|
2346 | if (tty_closing || o_tty_closing) { |
---|
2347 | struct task_struct *p; |
---|
2348 | |
---|
2349 | read_lock(&tasklist_lock); |
---|
2350 | do_each_task_pid(tty->session, PIDTYPE_SID, p) { |
---|
2351 | p->signal->tty = NULL; |
---|
2352 | } while_each_task_pid(tty->session, PIDTYPE_SID, p); |
---|
2353 | if (o_tty) |
---|
2354 | do_each_task_pid(o_tty->session, PIDTYPE_SID, p) { |
---|
2355 | p->signal->tty = NULL; |
---|
2356 | } while_each_task_pid(o_tty->session, PIDTYPE_SID, p); |
---|
2357 | read_unlock(&tasklist_lock); |
---|
2358 | } |
---|
2359 | |
---|
2360 | mutex_unlock(&tty_mutex); |
---|
2361 | |
---|
2362 | /* check whether both sides are closing ... */ |
---|
2363 | if (!tty_closing || (o_tty && !o_tty_closing)) |
---|
2364 | return; |
---|
2365 | |
---|
2366 | #ifdef TTY_DEBUG_HANGUP |
---|
2367 | printk(KERN_DEBUG "freeing tty structure..."); |
---|
2368 | #endif |
---|
2369 | /* |
---|
2370 | * Prevent flush_to_ldisc() from rescheduling the work for later. Then |
---|
2371 | * kill any delayed work. As this is the final close it does not |
---|
2372 | * race with the set_ldisc code path. |
---|
2373 | */ |
---|
2374 | clear_bit(TTY_LDISC, &tty->flags); |
---|
2375 | cancel_delayed_work(&tty->buf.work); |
---|
2376 | |
---|
2377 | /* |
---|
2378 | * Wait for ->hangup_work and ->buf.work handlers to terminate |
---|
2379 | */ |
---|
2380 | |
---|
2381 | flush_scheduled_work(); |
---|
2382 | |
---|
2383 | /* |
---|
2384 | * Wait for any short term users (we know they are just driver |
---|
2385 | * side waiters as the file is closing so user count on the file |
---|
2386 | * side is zero. |
---|
2387 | */ |
---|
2388 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
2389 | while(tty->ldisc.refcount) |
---|
2390 | { |
---|
2391 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
2392 | wait_event(tty_ldisc_wait, tty->ldisc.refcount == 0); |
---|
2393 | spin_lock_irqsave(&tty_ldisc_lock, flags); |
---|
2394 | } |
---|
2395 | spin_unlock_irqrestore(&tty_ldisc_lock, flags); |
---|
2396 | /* |
---|
2397 | * Shutdown the current line discipline, and reset it to N_TTY. |
---|
2398 | * N.B. why reset ldisc when we're releasing the memory?? |
---|
2399 | * |
---|
2400 | * FIXME: this MUST get fixed for the new reflocking |
---|
2401 | */ |
---|
2402 | if (tty->ldisc.close) |
---|
2403 | (tty->ldisc.close)(tty); |
---|
2404 | tty_ldisc_put(tty->ldisc.num); |
---|
2405 | |
---|
2406 | /* |
---|
2407 | * Switch the line discipline back |
---|
2408 | */ |
---|
2409 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); |
---|
2410 | tty_set_termios_ldisc(tty,N_TTY); |
---|
2411 | if (o_tty) { |
---|
2412 | /* FIXME: could o_tty be in setldisc here ? */ |
---|
2413 | clear_bit(TTY_LDISC, &o_tty->flags); |
---|
2414 | if (o_tty->ldisc.close) |
---|
2415 | (o_tty->ldisc.close)(o_tty); |
---|
2416 | tty_ldisc_put(o_tty->ldisc.num); |
---|
2417 | tty_ldisc_assign(o_tty, tty_ldisc_get(N_TTY)); |
---|
2418 | tty_set_termios_ldisc(o_tty,N_TTY); |
---|
2419 | } |
---|
2420 | /* |
---|
2421 | * The release_mem function takes care of the details of clearing |
---|
2422 | * the slots and preserving the termios structure. |
---|
2423 | */ |
---|
2424 | release_mem(tty, idx); |
---|
2425 | |
---|
2426 | #ifdef CONFIG_UNIX98_PTYS |
---|
2427 | /* Make this pty number available for reallocation */ |
---|
2428 | if (devpts) { |
---|
2429 | down(&allocated_ptys_lock); |
---|
2430 | idr_remove(&allocated_ptys, idx); |
---|
2431 | up(&allocated_ptys_lock); |
---|
2432 | } |
---|
2433 | #endif |
---|
2434 | |
---|
2435 | } |
---|
2436 | |
---|
2437 | /** |
---|
2438 | * tty_open - open a tty device |
---|
2439 | * @inode: inode of device file |
---|
2440 | * @filp: file pointer to tty |
---|
2441 | * |
---|
2442 | * tty_open and tty_release keep up the tty count that contains the |
---|
2443 | * number of opens done on a tty. We cannot use the inode-count, as |
---|
2444 | * different inodes might point to the same tty. |
---|
2445 | * |
---|
2446 | * Open-counting is needed for pty masters, as well as for keeping |
---|
2447 | * track of serial lines: DTR is dropped when the last close happens. |
---|
2448 | * (This is not done solely through tty->count, now. - Ted 1/27/92) |
---|
2449 | * |
---|
2450 | * The termios state of a pty is reset on first open so that |
---|
2451 | * settings don't persist across reuse. |
---|
2452 | * |
---|
2453 | * Locking: tty_mutex protects current->signal->tty, get_tty_driver and |
---|
2454 | * init_dev work. tty->count should protect the rest. |
---|
2455 | * task_lock is held to update task details for sessions |
---|
2456 | */ |
---|
2457 | |
---|
2458 | static int tty_open(struct inode * inode, struct file * filp) |
---|
2459 | { |
---|
2460 | struct tty_struct *tty; |
---|
2461 | int noctty, retval; |
---|
2462 | struct tty_driver *driver; |
---|
2463 | int index; |
---|
2464 | dev_t device = inode->i_rdev; |
---|
2465 | unsigned short saved_flags = filp->f_flags; |
---|
2466 | |
---|
2467 | nonseekable_open(inode, filp); |
---|
2468 | |
---|
2469 | retry_open: |
---|
2470 | noctty = filp->f_flags & O_NOCTTY; |
---|
2471 | index = -1; |
---|
2472 | retval = 0; |
---|
2473 | |
---|
2474 | mutex_lock(&tty_mutex); |
---|
2475 | |
---|
2476 | if (device == MKDEV(TTYAUX_MAJOR,0)) { |
---|
2477 | if (!current->signal->tty) { |
---|
2478 | mutex_unlock(&tty_mutex); |
---|
2479 | return -ENXIO; |
---|
2480 | } |
---|
2481 | driver = current->signal->tty->driver; |
---|
2482 | index = current->signal->tty->index; |
---|
2483 | filp->f_flags |= O_NONBLOCK; /* Don't let /dev/tty block */ |
---|
2484 | /* noctty = 1; */ |
---|
2485 | goto got_driver; |
---|
2486 | } |
---|
2487 | #ifdef CONFIG_VT |
---|
2488 | if (console_use_vt && (device == MKDEV(TTY_MAJOR,0))) { |
---|
2489 | extern struct tty_driver *console_driver; |
---|
2490 | driver = console_driver; |
---|
2491 | index = fg_console; |
---|
2492 | noctty = 1; |
---|
2493 | goto got_driver; |
---|
2494 | } |
---|
2495 | #endif |
---|
2496 | if (device == MKDEV(TTYAUX_MAJOR,1)) { |
---|
2497 | driver = console_device(&index); |
---|
2498 | if (driver) { |
---|
2499 | /* Don't let /dev/console block */ |
---|
2500 | filp->f_flags |= O_NONBLOCK; |
---|
2501 | noctty = 1; |
---|
2502 | goto got_driver; |
---|
2503 | } |
---|
2504 | mutex_unlock(&tty_mutex); |
---|
2505 | return -ENODEV; |
---|
2506 | } |
---|
2507 | |
---|
2508 | driver = get_tty_driver(device, &index); |
---|
2509 | if (!driver) { |
---|
2510 | mutex_unlock(&tty_mutex); |
---|
2511 | return -ENODEV; |
---|
2512 | } |
---|
2513 | got_driver: |
---|
2514 | retval = init_dev(driver, index, &tty); |
---|
2515 | mutex_unlock(&tty_mutex); |
---|
2516 | if (retval) |
---|
2517 | return retval; |
---|
2518 | |
---|
2519 | filp->private_data = tty; |
---|
2520 | file_move(filp, &tty->tty_files); |
---|
2521 | check_tty_count(tty, "tty_open"); |
---|
2522 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
---|
2523 | tty->driver->subtype == PTY_TYPE_MASTER) |
---|
2524 | noctty = 1; |
---|
2525 | #ifdef TTY_DEBUG_HANGUP |
---|
2526 | printk(KERN_DEBUG "opening %s...", tty->name); |
---|
2527 | #endif |
---|
2528 | if (!retval) { |
---|
2529 | if (tty->driver->open) |
---|
2530 | retval = tty->driver->open(tty, filp); |
---|
2531 | else |
---|
2532 | retval = -ENODEV; |
---|
2533 | } |
---|
2534 | filp->f_flags = saved_flags; |
---|
2535 | |
---|
2536 | if (!retval && test_bit(TTY_EXCLUSIVE, &tty->flags) && !capable(CAP_SYS_ADMIN)) |
---|
2537 | retval = -EBUSY; |
---|
2538 | |
---|
2539 | if (retval) { |
---|
2540 | #ifdef TTY_DEBUG_HANGUP |
---|
2541 | printk(KERN_DEBUG "error %d in opening %s...", retval, |
---|
2542 | tty->name); |
---|
2543 | #endif |
---|
2544 | release_dev(filp); |
---|
2545 | if (retval != -ERESTARTSYS) |
---|
2546 | return retval; |
---|
2547 | if (signal_pending(current)) |
---|
2548 | return retval; |
---|
2549 | schedule(); |
---|
2550 | /* |
---|
2551 | * Need to reset f_op in case a hangup happened. |
---|
2552 | */ |
---|
2553 | if (filp->f_op == &hung_up_tty_fops) |
---|
2554 | filp->f_op = &tty_fops; |
---|
2555 | goto retry_open; |
---|
2556 | } |
---|
2557 | if (!noctty && |
---|
2558 | current->signal->leader && |
---|
2559 | !current->signal->tty && |
---|
2560 | tty->session == 0) { |
---|
2561 | task_lock(current); |
---|
2562 | current->signal->tty = tty; |
---|
2563 | task_unlock(current); |
---|
2564 | current->signal->tty_old_pgrp = 0; |
---|
2565 | tty->session = current->signal->session; |
---|
2566 | tty->pgrp = process_group(current); |
---|
2567 | } |
---|
2568 | return 0; |
---|
2569 | } |
---|
2570 | |
---|
2571 | #ifdef CONFIG_UNIX98_PTYS |
---|
2572 | /** |
---|
2573 | * ptmx_open - open a unix 98 pty master |
---|
2574 | * @inode: inode of device file |
---|
2575 | * @filp: file pointer to tty |
---|
2576 | * |
---|
2577 | * Allocate a unix98 pty master device from the ptmx driver. |
---|
2578 | * |
---|
2579 | * Locking: tty_mutex protects theinit_dev work. tty->count should |
---|
2580 | protect the rest. |
---|
2581 | * allocated_ptys_lock handles the list of free pty numbers |
---|
2582 | */ |
---|
2583 | |
---|
2584 | static int ptmx_open(struct inode * inode, struct file * filp) |
---|
2585 | { |
---|
2586 | struct tty_struct *tty; |
---|
2587 | int retval; |
---|
2588 | int index; |
---|
2589 | int idr_ret; |
---|
2590 | |
---|
2591 | nonseekable_open(inode, filp); |
---|
2592 | |
---|
2593 | /* find a device that is not in use. */ |
---|
2594 | down(&allocated_ptys_lock); |
---|
2595 | if (!idr_pre_get(&allocated_ptys, GFP_KERNEL)) { |
---|
2596 | up(&allocated_ptys_lock); |
---|
2597 | return -ENOMEM; |
---|
2598 | } |
---|
2599 | idr_ret = idr_get_new(&allocated_ptys, NULL, &index); |
---|
2600 | if (idr_ret < 0) { |
---|
2601 | up(&allocated_ptys_lock); |
---|
2602 | if (idr_ret == -EAGAIN) |
---|
2603 | return -ENOMEM; |
---|
2604 | return -EIO; |
---|
2605 | } |
---|
2606 | if (index >= pty_limit) { |
---|
2607 | idr_remove(&allocated_ptys, index); |
---|
2608 | up(&allocated_ptys_lock); |
---|
2609 | return -EIO; |
---|
2610 | } |
---|
2611 | up(&allocated_ptys_lock); |
---|
2612 | |
---|
2613 | mutex_lock(&tty_mutex); |
---|
2614 | retval = init_dev(ptm_driver, index, &tty); |
---|
2615 | mutex_unlock(&tty_mutex); |
---|
2616 | |
---|
2617 | if (retval) |
---|
2618 | goto out; |
---|
2619 | |
---|
2620 | set_bit(TTY_PTY_LOCK, &tty->flags); /* LOCK THE SLAVE */ |
---|
2621 | filp->private_data = tty; |
---|
2622 | file_move(filp, &tty->tty_files); |
---|
2623 | |
---|
2624 | retval = -ENOMEM; |
---|
2625 | if (devpts_pty_new(tty->link)) |
---|
2626 | goto out1; |
---|
2627 | |
---|
2628 | check_tty_count(tty, "tty_open"); |
---|
2629 | retval = ptm_driver->open(tty, filp); |
---|
2630 | if (!retval) |
---|
2631 | return 0; |
---|
2632 | out1: |
---|
2633 | release_dev(filp); |
---|
2634 | return retval; |
---|
2635 | out: |
---|
2636 | down(&allocated_ptys_lock); |
---|
2637 | idr_remove(&allocated_ptys, index); |
---|
2638 | up(&allocated_ptys_lock); |
---|
2639 | return retval; |
---|
2640 | } |
---|
2641 | #endif |
---|
2642 | |
---|
2643 | /** |
---|
2644 | * tty_release - vfs callback for close |
---|
2645 | * @inode: inode of tty |
---|
2646 | * @filp: file pointer for handle to tty |
---|
2647 | * |
---|
2648 | * Called the last time each file handle is closed that references |
---|
2649 | * this tty. There may however be several such references. |
---|
2650 | * |
---|
2651 | * Locking: |
---|
2652 | * Takes bkl. See release_dev |
---|
2653 | */ |
---|
2654 | |
---|
2655 | static int tty_release(struct inode * inode, struct file * filp) |
---|
2656 | { |
---|
2657 | lock_kernel(); |
---|
2658 | release_dev(filp); |
---|
2659 | unlock_kernel(); |
---|
2660 | return 0; |
---|
2661 | } |
---|
2662 | |
---|
2663 | /** |
---|
2664 | * tty_poll - check tty status |
---|
2665 | * @filp: file being polled |
---|
2666 | * @wait: poll wait structures to update |
---|
2667 | * |
---|
2668 | * Call the line discipline polling method to obtain the poll |
---|
2669 | * status of the device. |
---|
2670 | * |
---|
2671 | * Locking: locks called line discipline but ldisc poll method |
---|
2672 | * may be re-entered freely by other callers. |
---|
2673 | */ |
---|
2674 | |
---|
2675 | static unsigned int tty_poll(struct file * filp, poll_table * wait) |
---|
2676 | { |
---|
2677 | struct tty_struct * tty; |
---|
2678 | struct tty_ldisc *ld; |
---|
2679 | int ret = 0; |
---|
2680 | |
---|
2681 | tty = (struct tty_struct *)filp->private_data; |
---|
2682 | if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_poll")) |
---|
2683 | return 0; |
---|
2684 | |
---|
2685 | ld = tty_ldisc_ref_wait(tty); |
---|
2686 | if (ld->poll) |
---|
2687 | ret = (ld->poll)(tty, filp, wait); |
---|
2688 | tty_ldisc_deref(ld); |
---|
2689 | return ret; |
---|
2690 | } |
---|
2691 | |
---|
2692 | static int tty_fasync(int fd, struct file * filp, int on) |
---|
2693 | { |
---|
2694 | struct tty_struct * tty; |
---|
2695 | int retval; |
---|
2696 | |
---|
2697 | tty = (struct tty_struct *)filp->private_data; |
---|
2698 | if (tty_paranoia_check(tty, filp->f_dentry->d_inode, "tty_fasync")) |
---|
2699 | return 0; |
---|
2700 | |
---|
2701 | retval = fasync_helper(fd, filp, on, &tty->fasync); |
---|
2702 | if (retval <= 0) |
---|
2703 | return retval; |
---|
2704 | |
---|
2705 | if (on) { |
---|
2706 | if (!waitqueue_active(&tty->read_wait)) |
---|
2707 | tty->minimum_to_wake = 1; |
---|
2708 | retval = f_setown(filp, (-tty->pgrp) ? : current->pid, 0); |
---|
2709 | if (retval) |
---|
2710 | return retval; |
---|
2711 | } else { |
---|
2712 | if (!tty->fasync && !waitqueue_active(&tty->read_wait)) |
---|
2713 | tty->minimum_to_wake = N_TTY_BUF_SIZE; |
---|
2714 | } |
---|
2715 | return 0; |
---|
2716 | } |
---|
2717 | |
---|
2718 | /** |
---|
2719 | * tiocsti - fake input character |
---|
2720 | * @tty: tty to fake input into |
---|
2721 | * @p: pointer to character |
---|
2722 | * |
---|
2723 | * Fake input to a tty device. Does the neccessary locking and |
---|
2724 | * input management. |
---|
2725 | * |
---|
2726 | * FIXME: does not honour flow control ?? |
---|
2727 | * |
---|
2728 | * Locking: |
---|
2729 | * Called functions take tty_ldisc_lock |
---|
2730 | * current->signal->tty check is safe without locks |
---|
2731 | */ |
---|
2732 | |
---|
2733 | static int tiocsti(struct tty_struct *tty, char __user *p) |
---|
2734 | { |
---|
2735 | char ch, mbz = 0; |
---|
2736 | struct tty_ldisc *ld; |
---|
2737 | |
---|
2738 | if ((current->signal->tty != tty) && !capable(CAP_SYS_ADMIN)) |
---|
2739 | return -EPERM; |
---|
2740 | if (get_user(ch, p)) |
---|
2741 | return -EFAULT; |
---|
2742 | ld = tty_ldisc_ref_wait(tty); |
---|
2743 | ld->receive_buf(tty, &ch, &mbz, 1); |
---|
2744 | tty_ldisc_deref(ld); |
---|
2745 | return 0; |
---|
2746 | } |
---|
2747 | |
---|
2748 | /** |
---|
2749 | * tiocgwinsz - implement window query ioctl |
---|
2750 | * @tty; tty |
---|
2751 | * @arg: user buffer for result |
---|
2752 | * |
---|
2753 | * Copies the kernel idea of the window size into the user buffer. No |
---|
2754 | * locking is done. |
---|
2755 | * |
---|
2756 | * FIXME: Returning random values racing a window size set is wrong |
---|
2757 | * should lock here against that |
---|
2758 | */ |
---|
2759 | |
---|
2760 | static int tiocgwinsz(struct tty_struct *tty, struct winsize __user * arg) |
---|
2761 | { |
---|
2762 | if (copy_to_user(arg, &tty->winsize, sizeof(*arg))) |
---|
2763 | return -EFAULT; |
---|
2764 | return 0; |
---|
2765 | } |
---|
2766 | |
---|
2767 | /** |
---|
2768 | * tiocswinsz - implement window size set ioctl |
---|
2769 | * @tty; tty |
---|
2770 | * @arg: user buffer for result |
---|
2771 | * |
---|
2772 | * Copies the user idea of the window size to the kernel. Traditionally |
---|
2773 | * this is just advisory information but for the Linux console it |
---|
2774 | * actually has driver level meaning and triggers a VC resize. |
---|
2775 | * |
---|
2776 | * Locking: |
---|
2777 | * The console_sem is used to ensure we do not try and resize |
---|
2778 | * the console twice at once. |
---|
2779 | * FIXME: Two racing size sets may leave the console and kernel |
---|
2780 | * parameters disagreeing. Is this exploitable ? |
---|
2781 | * FIXME: Random values racing a window size get is wrong |
---|
2782 | * should lock here against that |
---|
2783 | */ |
---|
2784 | |
---|
2785 | static int tiocswinsz(struct tty_struct *tty, struct tty_struct *real_tty, |
---|
2786 | struct winsize __user * arg) |
---|
2787 | { |
---|
2788 | struct winsize tmp_ws; |
---|
2789 | |
---|
2790 | if (copy_from_user(&tmp_ws, arg, sizeof(*arg))) |
---|
2791 | return -EFAULT; |
---|
2792 | if (!memcmp(&tmp_ws, &tty->winsize, sizeof(*arg))) |
---|
2793 | return 0; |
---|
2794 | #ifdef CONFIG_VT |
---|
2795 | if (tty->driver->type == TTY_DRIVER_TYPE_CONSOLE) { |
---|
2796 | int rc; |
---|
2797 | |
---|
2798 | acquire_console_sem(); |
---|
2799 | rc = vc_resize(tty->driver_data, tmp_ws.ws_col, tmp_ws.ws_row); |
---|
2800 | release_console_sem(); |
---|
2801 | if (rc) |
---|
2802 | return -ENXIO; |
---|
2803 | } |
---|
2804 | #endif |
---|
2805 | if (tty->pgrp > 0) |
---|
2806 | kill_pg(tty->pgrp, SIGWINCH, 1); |
---|
2807 | if ((real_tty->pgrp != tty->pgrp) && (real_tty->pgrp > 0)) |
---|
2808 | kill_pg(real_tty->pgrp, SIGWINCH, 1); |
---|
2809 | tty->winsize = tmp_ws; |
---|
2810 | real_tty->winsize = tmp_ws; |
---|
2811 | return 0; |
---|
2812 | } |
---|
2813 | |
---|
2814 | /** |
---|
2815 | * tioccons - allow admin to move logical console |
---|
2816 | * @file: the file to become console |
---|
2817 | * |
---|
2818 | * Allow the adminstrator to move the redirected console device |
---|
2819 | * |
---|
2820 | * Locking: uses redirect_lock to guard the redirect information |
---|
2821 | */ |
---|
2822 | |
---|
2823 | static int tioccons(struct file *file) |
---|
2824 | { |
---|
2825 | if (!capable(CAP_SYS_ADMIN)) |
---|
2826 | return -EPERM; |
---|
2827 | if (file->f_op->write == redirected_tty_write) { |
---|
2828 | struct file *f; |
---|
2829 | spin_lock(&redirect_lock); |
---|
2830 | f = redirect; |
---|
2831 | redirect = NULL; |
---|
2832 | spin_unlock(&redirect_lock); |
---|
2833 | if (f) |
---|
2834 | fput(f); |
---|
2835 | return 0; |
---|
2836 | } |
---|
2837 | spin_lock(&redirect_lock); |
---|
2838 | if (redirect) { |
---|
2839 | spin_unlock(&redirect_lock); |
---|
2840 | return -EBUSY; |
---|
2841 | } |
---|
2842 | get_file(file); |
---|
2843 | redirect = file; |
---|
2844 | spin_unlock(&redirect_lock); |
---|
2845 | return 0; |
---|
2846 | } |
---|
2847 | |
---|
2848 | /** |
---|
2849 | * fionbio - non blocking ioctl |
---|
2850 | * @file: file to set blocking value |
---|
2851 | * @p: user parameter |
---|
2852 | * |
---|
2853 | * Historical tty interfaces had a blocking control ioctl before |
---|
2854 | * the generic functionality existed. This piece of history is preserved |
---|
2855 | * in the expected tty API of posix OS's. |
---|
2856 | * |
---|
2857 | * Locking: none, the open fle handle ensures it won't go away. |
---|
2858 | */ |
---|
2859 | |
---|
2860 | static int fionbio(struct file *file, int __user *p) |
---|
2861 | { |
---|
2862 | int nonblock; |
---|
2863 | |
---|
2864 | if (get_user(nonblock, p)) |
---|
2865 | return -EFAULT; |
---|
2866 | |
---|
2867 | if (nonblock) |
---|
2868 | file->f_flags |= O_NONBLOCK; |
---|
2869 | else |
---|
2870 | file->f_flags &= ~O_NONBLOCK; |
---|
2871 | return 0; |
---|
2872 | } |
---|
2873 | |
---|
2874 | /** |
---|
2875 | * tiocsctty - set controlling tty |
---|
2876 | * @tty: tty structure |
---|
2877 | * @arg: user argument |
---|
2878 | * |
---|
2879 | * This ioctl is used to manage job control. It permits a session |
---|
2880 | * leader to set this tty as the controlling tty for the session. |
---|
2881 | * |
---|
2882 | * Locking: |
---|
2883 | * Takes tasklist lock internally to walk sessions |
---|
2884 | * Takes task_lock() when updating signal->tty |
---|
2885 | * |
---|
2886 | * FIXME: tty_mutex is needed to protect signal->tty references. |
---|
2887 | * FIXME: why task_lock on the signal->tty reference ?? |
---|
2888 | * |
---|
2889 | */ |
---|
2890 | |
---|
2891 | static int tiocsctty(struct tty_struct *tty, int arg) |
---|
2892 | { |
---|
2893 | struct task_struct *p; |
---|
2894 | |
---|
2895 | if (current->signal->leader && |
---|
2896 | (current->signal->session == tty->session)) |
---|
2897 | return 0; |
---|
2898 | /* |
---|
2899 | * The process must be a session leader and |
---|
2900 | * not have a controlling tty already. |
---|
2901 | */ |
---|
2902 | if (!current->signal->leader || current->signal->tty) |
---|
2903 | return -EPERM; |
---|
2904 | if (tty->session > 0) { |
---|
2905 | /* |
---|
2906 | * This tty is already the controlling |
---|
2907 | * tty for another session group! |
---|
2908 | */ |
---|
2909 | if ((arg == 1) && capable(CAP_SYS_ADMIN)) { |
---|
2910 | /* |
---|
2911 | * Steal it away |
---|
2912 | */ |
---|
2913 | |
---|
2914 | read_lock(&tasklist_lock); |
---|
2915 | do_each_task_pid(tty->session, PIDTYPE_SID, p) { |
---|
2916 | p->signal->tty = NULL; |
---|
2917 | } while_each_task_pid(tty->session, PIDTYPE_SID, p); |
---|
2918 | read_unlock(&tasklist_lock); |
---|
2919 | } else |
---|
2920 | return -EPERM; |
---|
2921 | } |
---|
2922 | task_lock(current); |
---|
2923 | current->signal->tty = tty; |
---|
2924 | task_unlock(current); |
---|
2925 | current->signal->tty_old_pgrp = 0; |
---|
2926 | tty->session = current->signal->session; |
---|
2927 | tty->pgrp = process_group(current); |
---|
2928 | return 0; |
---|
2929 | } |
---|
2930 | |
---|
2931 | /** |
---|
2932 | * tiocgpgrp - get process group |
---|
2933 | * @tty: tty passed by user |
---|
2934 | * @real_tty: tty side of the tty pased by the user if a pty else the tty |
---|
2935 | * @p: returned pid |
---|
2936 | * |
---|
2937 | * Obtain the process group of the tty. If there is no process group |
---|
2938 | * return an error. |
---|
2939 | * |
---|
2940 | * Locking: none. Reference to ->signal->tty is safe. |
---|
2941 | */ |
---|
2942 | |
---|
2943 | static int tiocgpgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
---|
2944 | { |
---|
2945 | /* |
---|
2946 | * (tty == real_tty) is a cheap way of |
---|
2947 | * testing if the tty is NOT a master pty. |
---|
2948 | */ |
---|
2949 | if (tty == real_tty && current->signal->tty != real_tty) |
---|
2950 | return -ENOTTY; |
---|
2951 | return put_user(real_tty->pgrp, p); |
---|
2952 | } |
---|
2953 | |
---|
2954 | /** |
---|
2955 | * tiocspgrp - attempt to set process group |
---|
2956 | * @tty: tty passed by user |
---|
2957 | * @real_tty: tty side device matching tty passed by user |
---|
2958 | * @p: pid pointer |
---|
2959 | * |
---|
2960 | * Set the process group of the tty to the session passed. Only |
---|
2961 | * permitted where the tty session is our session. |
---|
2962 | * |
---|
2963 | * Locking: None |
---|
2964 | * |
---|
2965 | * FIXME: current->signal->tty referencing is unsafe. |
---|
2966 | */ |
---|
2967 | |
---|
2968 | static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
---|
2969 | { |
---|
2970 | pid_t pgrp; |
---|
2971 | int retval = tty_check_change(real_tty); |
---|
2972 | |
---|
2973 | if (retval == -EIO) |
---|
2974 | return -ENOTTY; |
---|
2975 | if (retval) |
---|
2976 | return retval; |
---|
2977 | if (!current->signal->tty || |
---|
2978 | (current->signal->tty != real_tty) || |
---|
2979 | (real_tty->session != current->signal->session)) |
---|
2980 | return -ENOTTY; |
---|
2981 | if (get_user(pgrp, p)) |
---|
2982 | return -EFAULT; |
---|
2983 | if (pgrp < 0) |
---|
2984 | return -EINVAL; |
---|
2985 | if (session_of_pgrp(pgrp) != current->signal->session) |
---|
2986 | return -EPERM; |
---|
2987 | real_tty->pgrp = pgrp; |
---|
2988 | return 0; |
---|
2989 | } |
---|
2990 | |
---|
2991 | /** |
---|
2992 | * tiocgsid - get session id |
---|
2993 | * @tty: tty passed by user |
---|
2994 | * @real_tty: tty side of the tty pased by the user if a pty else the tty |
---|
2995 | * @p: pointer to returned session id |
---|
2996 | * |
---|
2997 | * Obtain the session id of the tty. If there is no session |
---|
2998 | * return an error. |
---|
2999 | * |
---|
3000 | * Locking: none. Reference to ->signal->tty is safe. |
---|
3001 | */ |
---|
3002 | |
---|
3003 | static int tiocgsid(struct tty_struct *tty, struct tty_struct *real_tty, pid_t __user *p) |
---|
3004 | { |
---|
3005 | /* |
---|
3006 | * (tty == real_tty) is a cheap way of |
---|
3007 | * testing if the tty is NOT a master pty. |
---|
3008 | */ |
---|
3009 | if (tty == real_tty && current->signal->tty != real_tty) |
---|
3010 | return -ENOTTY; |
---|
3011 | if (real_tty->session <= 0) |
---|
3012 | return -ENOTTY; |
---|
3013 | return put_user(real_tty->session, p); |
---|
3014 | } |
---|
3015 | |
---|
3016 | /** |
---|
3017 | * tiocsetd - set line discipline |
---|
3018 | * @tty: tty device |
---|
3019 | * @p: pointer to user data |
---|
3020 | * |
---|
3021 | * Set the line discipline according to user request. |
---|
3022 | * |
---|
3023 | * Locking: see tty_set_ldisc, this function is just a helper |
---|
3024 | */ |
---|
3025 | |
---|
3026 | static int tiocsetd(struct tty_struct *tty, int __user *p) |
---|
3027 | { |
---|
3028 | int ldisc; |
---|
3029 | |
---|
3030 | if (get_user(ldisc, p)) |
---|
3031 | return -EFAULT; |
---|
3032 | return tty_set_ldisc(tty, ldisc); |
---|
3033 | } |
---|
3034 | |
---|
3035 | /** |
---|
3036 | * send_break - performed time break |
---|
3037 | * @tty: device to break on |
---|
3038 | * @duration: timeout in mS |
---|
3039 | * |
---|
3040 | * Perform a timed break on hardware that lacks its own driver level |
---|
3041 | * timed break functionality. |
---|
3042 | * |
---|
3043 | * Locking: |
---|
3044 | * None |
---|
3045 | * |
---|
3046 | * FIXME: |
---|
3047 | * What if two overlap |
---|
3048 | */ |
---|
3049 | |
---|
3050 | static int send_break(struct tty_struct *tty, unsigned int duration) |
---|
3051 | { |
---|
3052 | tty->driver->break_ctl(tty, -1); |
---|
3053 | if (!signal_pending(current)) { |
---|
3054 | msleep_interruptible(duration); |
---|
3055 | } |
---|
3056 | tty->driver->break_ctl(tty, 0); |
---|
3057 | if (signal_pending(current)) |
---|
3058 | return -EINTR; |
---|
3059 | return 0; |
---|
3060 | } |
---|
3061 | |
---|
3062 | /** |
---|
3063 | * tiocmget - get modem status |
---|
3064 | * @tty: tty device |
---|
3065 | * @file: user file pointer |
---|
3066 | * @p: pointer to result |
---|
3067 | * |
---|
3068 | * Obtain the modem status bits from the tty driver if the feature |
---|
3069 | * is supported. Return -EINVAL if it is not available. |
---|
3070 | * |
---|
3071 | * Locking: none (up to the driver) |
---|
3072 | */ |
---|
3073 | |
---|
3074 | static int tty_tiocmget(struct tty_struct *tty, struct file *file, int __user *p) |
---|
3075 | { |
---|
3076 | int retval = -EINVAL; |
---|
3077 | |
---|
3078 | if (tty->driver->tiocmget) { |
---|
3079 | retval = tty->driver->tiocmget(tty, file); |
---|
3080 | |
---|
3081 | if (retval >= 0) |
---|
3082 | retval = put_user(retval, p); |
---|
3083 | } |
---|
3084 | return retval; |
---|
3085 | } |
---|
3086 | |
---|
3087 | /** |
---|
3088 | * tiocmset - set modem status |
---|
3089 | * @tty: tty device |
---|
3090 | * @file: user file pointer |
---|
3091 | * @cmd: command - clear bits, set bits or set all |
---|
3092 | * @p: pointer to desired bits |
---|
3093 | * |
---|
3094 | * Set the modem status bits from the tty driver if the feature |
---|
3095 | * is supported. Return -EINVAL if it is not available. |
---|
3096 | * |
---|
3097 | * Locking: none (up to the driver) |
---|
3098 | */ |
---|
3099 | |
---|
3100 | static int tty_tiocmset(struct tty_struct *tty, struct file *file, unsigned int cmd, |
---|
3101 | unsigned __user *p) |
---|
3102 | { |
---|
3103 | int retval = -EINVAL; |
---|
3104 | |
---|
3105 | if (tty->driver->tiocmset) { |
---|
3106 | unsigned int set, clear, val; |
---|
3107 | |
---|
3108 | retval = get_user(val, p); |
---|
3109 | if (retval) |
---|
3110 | return retval; |
---|
3111 | |
---|
3112 | set = clear = 0; |
---|
3113 | switch (cmd) { |
---|
3114 | case TIOCMBIS: |
---|
3115 | set = val; |
---|
3116 | break; |
---|
3117 | case TIOCMBIC: |
---|
3118 | clear = val; |
---|
3119 | break; |
---|
3120 | case TIOCMSET: |
---|
3121 | set = val; |
---|
3122 | clear = ~val; |
---|
3123 | break; |
---|
3124 | } |
---|
3125 | |
---|
3126 | set &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; |
---|
3127 | clear &= TIOCM_DTR|TIOCM_RTS|TIOCM_OUT1|TIOCM_OUT2|TIOCM_LOOP; |
---|
3128 | |
---|
3129 | retval = tty->driver->tiocmset(tty, file, set, clear); |
---|
3130 | } |
---|
3131 | return retval; |
---|
3132 | } |
---|
3133 | |
---|
3134 | /* |
---|
3135 | * Split this up, as gcc can choke on it otherwise.. |
---|
3136 | */ |
---|
3137 | int tty_ioctl(struct inode * inode, struct file * file, |
---|
3138 | unsigned int cmd, unsigned long arg) |
---|
3139 | { |
---|
3140 | struct tty_struct *tty, *real_tty; |
---|
3141 | void __user *p = (void __user *)arg; |
---|
3142 | int retval; |
---|
3143 | struct tty_ldisc *ld; |
---|
3144 | |
---|
3145 | tty = (struct tty_struct *)file->private_data; |
---|
3146 | if (tty_paranoia_check(tty, inode, "tty_ioctl")) |
---|
3147 | return -EINVAL; |
---|
3148 | |
---|
3149 | real_tty = tty; |
---|
3150 | if (tty->driver->type == TTY_DRIVER_TYPE_PTY && |
---|
3151 | tty->driver->subtype == PTY_TYPE_MASTER) |
---|
3152 | real_tty = tty->link; |
---|
3153 | |
---|
3154 | /* |
---|
3155 | * Break handling by driver |
---|
3156 | */ |
---|
3157 | if (!tty->driver->break_ctl) { |
---|
3158 | switch(cmd) { |
---|
3159 | case TIOCSBRK: |
---|
3160 | case TIOCCBRK: |
---|
3161 | if (tty->driver->ioctl) |
---|
3162 | return tty->driver->ioctl(tty, file, cmd, arg); |
---|
3163 | return -EINVAL; |
---|
3164 | |
---|
3165 | /* These two ioctl's always return success; even if */ |
---|
3166 | /* the driver doesn't support them. */ |
---|
3167 | case TCSBRK: |
---|
3168 | case TCSBRKP: |
---|
3169 | if (!tty->driver->ioctl) |
---|
3170 | return 0; |
---|
3171 | retval = tty->driver->ioctl(tty, file, cmd, arg); |
---|
3172 | if (retval == -ENOIOCTLCMD) |
---|
3173 | retval = 0; |
---|
3174 | return retval; |
---|
3175 | } |
---|
3176 | } |
---|
3177 | |
---|
3178 | /* |
---|
3179 | * Factor out some common prep work |
---|
3180 | */ |
---|
3181 | switch (cmd) { |
---|
3182 | case TIOCSETD: |
---|
3183 | case TIOCSBRK: |
---|
3184 | case TIOCCBRK: |
---|
3185 | case TCSBRK: |
---|
3186 | case TCSBRKP: |
---|
3187 | retval = tty_check_change(tty); |
---|
3188 | if (retval) |
---|
3189 | return retval; |
---|
3190 | if (cmd != TIOCCBRK) { |
---|
3191 | tty_wait_until_sent(tty, 0); |
---|
3192 | if (signal_pending(current)) |
---|
3193 | return -EINTR; |
---|
3194 | } |
---|
3195 | break; |
---|
3196 | } |
---|
3197 | |
---|
3198 | switch (cmd) { |
---|
3199 | case TIOCSTI: |
---|
3200 | return tiocsti(tty, p); |
---|
3201 | case TIOCGWINSZ: |
---|
3202 | return tiocgwinsz(tty, p); |
---|
3203 | case TIOCSWINSZ: |
---|
3204 | return tiocswinsz(tty, real_tty, p); |
---|
3205 | case TIOCCONS: |
---|
3206 | return real_tty!=tty ? -EINVAL : tioccons(file); |
---|
3207 | case FIONBIO: |
---|
3208 | return fionbio(file, p); |
---|
3209 | case TIOCEXCL: |
---|
3210 | set_bit(TTY_EXCLUSIVE, &tty->flags); |
---|
3211 | return 0; |
---|
3212 | case TIOCNXCL: |
---|
3213 | clear_bit(TTY_EXCLUSIVE, &tty->flags); |
---|
3214 | return 0; |
---|
3215 | case TIOCNOTTY: |
---|
3216 | /* FIXME: taks lock or tty_mutex ? */ |
---|
3217 | if (current->signal->tty != tty) |
---|
3218 | return -ENOTTY; |
---|
3219 | if (current->signal->leader) |
---|
3220 | disassociate_ctty(0); |
---|
3221 | task_lock(current); |
---|
3222 | current->signal->tty = NULL; |
---|
3223 | task_unlock(current); |
---|
3224 | return 0; |
---|
3225 | case TIOCSCTTY: |
---|
3226 | return tiocsctty(tty, arg); |
---|
3227 | case TIOCGPGRP: |
---|
3228 | return tiocgpgrp(tty, real_tty, p); |
---|
3229 | case TIOCSPGRP: |
---|
3230 | return tiocspgrp(tty, real_tty, p); |
---|
3231 | case TIOCGSID: |
---|
3232 | return tiocgsid(tty, real_tty, p); |
---|
3233 | case TIOCGETD: |
---|
3234 | /* FIXME: check this is ok */ |
---|
3235 | return put_user(tty->ldisc.num, (int __user *)p); |
---|
3236 | case TIOCSETD: |
---|
3237 | return tiocsetd(tty, p); |
---|
3238 | #ifdef CONFIG_VT |
---|
3239 | case TIOCLINUX: |
---|
3240 | return tioclinux(tty, arg); |
---|
3241 | #endif |
---|
3242 | /* |
---|
3243 | * Break handling |
---|
3244 | */ |
---|
3245 | case TIOCSBRK: /* Turn break on, unconditionally */ |
---|
3246 | tty->driver->break_ctl(tty, -1); |
---|
3247 | return 0; |
---|
3248 | |
---|
3249 | case TIOCCBRK: /* Turn break off, unconditionally */ |
---|
3250 | tty->driver->break_ctl(tty, 0); |
---|
3251 | return 0; |
---|
3252 | case TCSBRK: /* SVID version: non-zero arg --> no break */ |
---|
3253 | /* non-zero arg means wait for all output data |
---|
3254 | * to be sent (performed above) but don't send break. |
---|
3255 | * This is used by the tcdrain() termios function. |
---|
3256 | */ |
---|
3257 | if (!arg) |
---|
3258 | return send_break(tty, 250); |
---|
3259 | return 0; |
---|
3260 | case TCSBRKP: /* support for POSIX tcsendbreak() */ |
---|
3261 | return send_break(tty, arg ? arg*100 : 250); |
---|
3262 | |
---|
3263 | case TIOCMGET: |
---|
3264 | return tty_tiocmget(tty, file, p); |
---|
3265 | |
---|
3266 | case TIOCMSET: |
---|
3267 | case TIOCMBIC: |
---|
3268 | case TIOCMBIS: |
---|
3269 | return tty_tiocmset(tty, file, cmd, p); |
---|
3270 | } |
---|
3271 | if (tty->driver->ioctl) { |
---|
3272 | retval = (tty->driver->ioctl)(tty, file, cmd, arg); |
---|
3273 | if (retval != -ENOIOCTLCMD) |
---|
3274 | return retval; |
---|
3275 | } |
---|
3276 | ld = tty_ldisc_ref_wait(tty); |
---|
3277 | retval = -EINVAL; |
---|
3278 | if (ld->ioctl) { |
---|
3279 | retval = ld->ioctl(tty, file, cmd, arg); |
---|
3280 | if (retval == -ENOIOCTLCMD) |
---|
3281 | retval = -EINVAL; |
---|
3282 | } |
---|
3283 | tty_ldisc_deref(ld); |
---|
3284 | return retval; |
---|
3285 | } |
---|
3286 | |
---|
3287 | |
---|
3288 | /* |
---|
3289 | * This implements the "Secure Attention Key" --- the idea is to |
---|
3290 | * prevent trojan horses by killing all processes associated with this |
---|
3291 | * tty when the user hits the "Secure Attention Key". Required for |
---|
3292 | * super-paranoid applications --- see the Orange Book for more details. |
---|
3293 | * |
---|
3294 | * This code could be nicer; ideally it should send a HUP, wait a few |
---|
3295 | * seconds, then send a INT, and then a KILL signal. But you then |
---|
3296 | * have to coordinate with the init process, since all processes associated |
---|
3297 | * with the current tty must be dead before the new getty is allowed |
---|
3298 | * to spawn. |
---|
3299 | * |
---|
3300 | * Now, if it would be correct ;-/ The current code has a nasty hole - |
---|
3301 | * it doesn't catch files in flight. We may send the descriptor to ourselves |
---|
3302 | * via AF_UNIX socket, close it and later fetch from socket. FIXME. |
---|
3303 | * |
---|
3304 | * Nasty bug: do_SAK is being called in interrupt context. This can |
---|
3305 | * deadlock. We punt it up to process context. AKPM - 16Mar2001 |
---|
3306 | */ |
---|
3307 | static void __do_SAK(void *arg) |
---|
3308 | { |
---|
3309 | #ifdef TTY_SOFT_SAK |
---|
3310 | tty_hangup(tty); |
---|
3311 | #else |
---|
3312 | struct tty_struct *tty = arg; |
---|
3313 | struct task_struct *g, *p; |
---|
3314 | int session; |
---|
3315 | int i; |
---|
3316 | struct file *filp; |
---|
3317 | struct tty_ldisc *disc; |
---|
3318 | struct fdtable *fdt; |
---|
3319 | |
---|
3320 | if (!tty) |
---|
3321 | return; |
---|
3322 | session = tty->session; |
---|
3323 | |
---|
3324 | /* We don't want an ldisc switch during this */ |
---|
3325 | disc = tty_ldisc_ref(tty); |
---|
3326 | if (disc && disc->flush_buffer) |
---|
3327 | disc->flush_buffer(tty); |
---|
3328 | tty_ldisc_deref(disc); |
---|
3329 | |
---|
3330 | if (tty->driver->flush_buffer) |
---|
3331 | tty->driver->flush_buffer(tty); |
---|
3332 | |
---|
3333 | read_lock(&tasklist_lock); |
---|
3334 | /* Kill the entire session */ |
---|
3335 | do_each_task_pid(session, PIDTYPE_SID, p) { |
---|
3336 | printk(KERN_NOTICE "SAK: killed process %d" |
---|
3337 | " (%s): p->signal->session==tty->session\n", |
---|
3338 | p->pid, p->comm); |
---|
3339 | send_sig(SIGKILL, p, 1); |
---|
3340 | } while_each_task_pid(session, PIDTYPE_SID, p); |
---|
3341 | /* Now kill any processes that happen to have the |
---|
3342 | * tty open. |
---|
3343 | */ |
---|
3344 | do_each_thread(g, p) { |
---|
3345 | if (p->signal->tty == tty) { |
---|
3346 | printk(KERN_NOTICE "SAK: killed process %d" |
---|
3347 | " (%s): p->signal->session==tty->session\n", |
---|
3348 | p->pid, p->comm); |
---|
3349 | send_sig(SIGKILL, p, 1); |
---|
3350 | continue; |
---|
3351 | } |
---|
3352 | task_lock(p); |
---|
3353 | if (p->files) { |
---|
3354 | /* |
---|
3355 | * We don't take a ref to the file, so we must |
---|
3356 | * hold ->file_lock instead. |
---|
3357 | */ |
---|
3358 | spin_lock(&p->files->file_lock); |
---|
3359 | fdt = files_fdtable(p->files); |
---|
3360 | for (i=0; i < fdt->max_fds; i++) { |
---|
3361 | filp = fcheck_files(p->files, i); |
---|
3362 | if (!filp) |
---|
3363 | continue; |
---|
3364 | if (filp->f_op->read == tty_read && |
---|
3365 | filp->private_data == tty) { |
---|
3366 | printk(KERN_NOTICE "SAK: killed process %d" |
---|
3367 | " (%s): fd#%d opened to the tty\n", |
---|
3368 | p->pid, p->comm, i); |
---|
3369 | force_sig(SIGKILL, p); |
---|
3370 | break; |
---|
3371 | } |
---|
3372 | } |
---|
3373 | spin_unlock(&p->files->file_lock); |
---|
3374 | } |
---|
3375 | task_unlock(p); |
---|
3376 | } while_each_thread(g, p); |
---|
3377 | read_unlock(&tasklist_lock); |
---|
3378 | #endif |
---|
3379 | } |
---|
3380 | |
---|
3381 | /* |
---|
3382 | * The tq handling here is a little racy - tty->SAK_work may already be queued. |
---|
3383 | * Fortunately we don't need to worry, because if ->SAK_work is already queued, |
---|
3384 | * the values which we write to it will be identical to the values which it |
---|
3385 | * already has. --akpm |
---|
3386 | */ |
---|
3387 | void do_SAK(struct tty_struct *tty) |
---|
3388 | { |
---|
3389 | if (!tty) |
---|
3390 | return; |
---|
3391 | PREPARE_WORK(&tty->SAK_work, __do_SAK, tty); |
---|
3392 | schedule_work(&tty->SAK_work); |
---|
3393 | } |
---|
3394 | |
---|
3395 | EXPORT_SYMBOL(do_SAK); |
---|
3396 | |
---|
3397 | /** |
---|
3398 | * flush_to_ldisc |
---|
3399 | * @private_: tty structure passed from work queue. |
---|
3400 | * |
---|
3401 | * This routine is called out of the software interrupt to flush data |
---|
3402 | * from the buffer chain to the line discipline. |
---|
3403 | * |
---|
3404 | * Locking: holds tty->buf.lock to guard buffer list. Drops the lock |
---|
3405 | * while invoking the line discipline receive_buf method. The |
---|
3406 | * receive_buf method is single threaded for each tty instance. |
---|
3407 | */ |
---|
3408 | |
---|
3409 | static void flush_to_ldisc(void *private_) |
---|
3410 | { |
---|
3411 | struct tty_struct *tty = (struct tty_struct *) private_; |
---|
3412 | unsigned long flags; |
---|
3413 | struct tty_ldisc *disc; |
---|
3414 | struct tty_buffer *tbuf, *head; |
---|
3415 | char *char_buf; |
---|
3416 | unsigned char *flag_buf; |
---|
3417 | |
---|
3418 | disc = tty_ldisc_ref(tty); |
---|
3419 | if (disc == NULL) /* !TTY_LDISC */ |
---|
3420 | return; |
---|
3421 | |
---|
3422 | spin_lock_irqsave(&tty->buf.lock, flags); |
---|
3423 | head = tty->buf.head; |
---|
3424 | if (head != NULL) { |
---|
3425 | tty->buf.head = NULL; |
---|
3426 | for (;;) { |
---|
3427 | int count = head->commit - head->read; |
---|
3428 | if (!count) { |
---|
3429 | if (head->next == NULL) |
---|
3430 | break; |
---|
3431 | tbuf = head; |
---|
3432 | head = head->next; |
---|
3433 | tty_buffer_free(tty, tbuf); |
---|
3434 | continue; |
---|
3435 | } |
---|
3436 | if (!tty->receive_room) { |
---|
3437 | schedule_delayed_work(&tty->buf.work, 1); |
---|
3438 | break; |
---|
3439 | } |
---|
3440 | if (count > tty->receive_room) |
---|
3441 | count = tty->receive_room; |
---|
3442 | char_buf = head->char_buf_ptr + head->read; |
---|
3443 | flag_buf = head->flag_buf_ptr + head->read; |
---|
3444 | head->read += count; |
---|
3445 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
---|
3446 | disc->receive_buf(tty, char_buf, flag_buf, count); |
---|
3447 | spin_lock_irqsave(&tty->buf.lock, flags); |
---|
3448 | } |
---|
3449 | tty->buf.head = head; |
---|
3450 | } |
---|
3451 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
---|
3452 | |
---|
3453 | tty_ldisc_deref(disc); |
---|
3454 | } |
---|
3455 | |
---|
3456 | /* |
---|
3457 | * Routine which returns the baud rate of the tty |
---|
3458 | * |
---|
3459 | * Note that the baud_table needs to be kept in sync with the |
---|
3460 | * include/asm/termbits.h file. |
---|
3461 | */ |
---|
3462 | static int baud_table[] = { |
---|
3463 | 0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, |
---|
3464 | 9600, 19200, 38400, 57600, 115200, 230400, 460800, |
---|
3465 | #ifdef __sparc__ |
---|
3466 | 76800, 153600, 307200, 614400, 921600 |
---|
3467 | #else |
---|
3468 | 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, |
---|
3469 | 2500000, 3000000, 3500000, 4000000 |
---|
3470 | #endif |
---|
3471 | }; |
---|
3472 | |
---|
3473 | static int n_baud_table = ARRAY_SIZE(baud_table); |
---|
3474 | |
---|
3475 | /** |
---|
3476 | * tty_termios_baud_rate |
---|
3477 | * @termios: termios structure |
---|
3478 | * |
---|
3479 | * Convert termios baud rate data into a speed. This should be called |
---|
3480 | * with the termios lock held if this termios is a terminal termios |
---|
3481 | * structure. May change the termios data. |
---|
3482 | * |
---|
3483 | * Locking: none |
---|
3484 | */ |
---|
3485 | |
---|
3486 | int tty_termios_baud_rate(struct termios *termios) |
---|
3487 | { |
---|
3488 | unsigned int cbaud; |
---|
3489 | |
---|
3490 | cbaud = termios->c_cflag & CBAUD; |
---|
3491 | |
---|
3492 | if (cbaud & CBAUDEX) { |
---|
3493 | cbaud &= ~CBAUDEX; |
---|
3494 | |
---|
3495 | if (cbaud < 1 || cbaud + 15 > n_baud_table) |
---|
3496 | termios->c_cflag &= ~CBAUDEX; |
---|
3497 | else |
---|
3498 | cbaud += 15; |
---|
3499 | } |
---|
3500 | return baud_table[cbaud]; |
---|
3501 | } |
---|
3502 | |
---|
3503 | EXPORT_SYMBOL(tty_termios_baud_rate); |
---|
3504 | |
---|
3505 | /** |
---|
3506 | * tty_get_baud_rate - get tty bit rates |
---|
3507 | * @tty: tty to query |
---|
3508 | * |
---|
3509 | * Returns the baud rate as an integer for this terminal. The |
---|
3510 | * termios lock must be held by the caller and the terminal bit |
---|
3511 | * flags may be updated. |
---|
3512 | * |
---|
3513 | * Locking: none |
---|
3514 | */ |
---|
3515 | |
---|
3516 | int tty_get_baud_rate(struct tty_struct *tty) |
---|
3517 | { |
---|
3518 | int baud = tty_termios_baud_rate(tty->termios); |
---|
3519 | |
---|
3520 | if (baud == 38400 && tty->alt_speed) { |
---|
3521 | if (!tty->warned) { |
---|
3522 | printk(KERN_WARNING "Use of setserial/setrocket to " |
---|
3523 | "set SPD_* flags is deprecated\n"); |
---|
3524 | tty->warned = 1; |
---|
3525 | } |
---|
3526 | baud = tty->alt_speed; |
---|
3527 | } |
---|
3528 | |
---|
3529 | return baud; |
---|
3530 | } |
---|
3531 | |
---|
3532 | EXPORT_SYMBOL(tty_get_baud_rate); |
---|
3533 | |
---|
3534 | /** |
---|
3535 | * tty_flip_buffer_push - terminal |
---|
3536 | * @tty: tty to push |
---|
3537 | * |
---|
3538 | * Queue a push of the terminal flip buffers to the line discipline. This |
---|
3539 | * function must not be called from IRQ context if tty->low_latency is set. |
---|
3540 | * |
---|
3541 | * In the event of the queue being busy for flipping the work will be |
---|
3542 | * held off and retried later. |
---|
3543 | * |
---|
3544 | * Locking: tty buffer lock. Driver locks in low latency mode. |
---|
3545 | */ |
---|
3546 | |
---|
3547 | void tty_flip_buffer_push(struct tty_struct *tty) |
---|
3548 | { |
---|
3549 | unsigned long flags; |
---|
3550 | spin_lock_irqsave(&tty->buf.lock, flags); |
---|
3551 | if (tty->buf.tail != NULL) |
---|
3552 | tty->buf.tail->commit = tty->buf.tail->used; |
---|
3553 | spin_unlock_irqrestore(&tty->buf.lock, flags); |
---|
3554 | |
---|
3555 | if (tty->low_latency) |
---|
3556 | flush_to_ldisc((void *) tty); |
---|
3557 | else |
---|
3558 | schedule_delayed_work(&tty->buf.work, 1); |
---|
3559 | } |
---|
3560 | |
---|
3561 | EXPORT_SYMBOL(tty_flip_buffer_push); |
---|
3562 | |
---|
3563 | |
---|
3564 | /** |
---|
3565 | * initialize_tty_struct |
---|
3566 | * @tty: tty to initialize |
---|
3567 | * |
---|
3568 | * This subroutine initializes a tty structure that has been newly |
---|
3569 | * allocated. |
---|
3570 | * |
---|
3571 | * Locking: none - tty in question must not be exposed at this point |
---|
3572 | */ |
---|
3573 | |
---|
3574 | static void initialize_tty_struct(struct tty_struct *tty) |
---|
3575 | { |
---|
3576 | memset(tty, 0, sizeof(struct tty_struct)); |
---|
3577 | tty->magic = TTY_MAGIC; |
---|
3578 | tty_ldisc_assign(tty, tty_ldisc_get(N_TTY)); |
---|
3579 | tty->pgrp = -1; |
---|
3580 | tty->overrun_time = jiffies; |
---|
3581 | tty->buf.head = tty->buf.tail = NULL; |
---|
3582 | tty_buffer_init(tty); |
---|
3583 | INIT_WORK(&tty->buf.work, flush_to_ldisc, tty); |
---|
3584 | init_MUTEX(&tty->buf.pty_sem); |
---|
3585 | init_MUTEX(&tty->termios_sem); |
---|
3586 | init_waitqueue_head(&tty->write_wait); |
---|
3587 | init_waitqueue_head(&tty->read_wait); |
---|
3588 | INIT_WORK(&tty->hangup_work, do_tty_hangup, tty); |
---|
3589 | mutex_init(&tty->atomic_read_lock); |
---|
3590 | mutex_init(&tty->atomic_write_lock); |
---|
3591 | spin_lock_init(&tty->read_lock); |
---|
3592 | INIT_LIST_HEAD(&tty->tty_files); |
---|
3593 | INIT_WORK(&tty->SAK_work, NULL, NULL); |
---|
3594 | } |
---|
3595 | |
---|
3596 | /* |
---|
3597 | * The default put_char routine if the driver did not define one. |
---|
3598 | */ |
---|
3599 | |
---|
3600 | static void tty_default_put_char(struct tty_struct *tty, unsigned char ch) |
---|
3601 | { |
---|
3602 | tty->driver->write(tty, &ch, 1); |
---|
3603 | } |
---|
3604 | |
---|
3605 | static struct class *tty_class; |
---|
3606 | |
---|
3607 | /** |
---|
3608 | * tty_register_device - register a tty device |
---|
3609 | * @driver: the tty driver that describes the tty device |
---|
3610 | * @index: the index in the tty driver for this tty device |
---|
3611 | * @device: a struct device that is associated with this tty device. |
---|
3612 | * This field is optional, if there is no known struct device |
---|
3613 | * for this tty device it can be set to NULL safely. |
---|
3614 | * |
---|
3615 | * Returns a pointer to the class device (or ERR_PTR(-EFOO) on error). |
---|
3616 | * |
---|
3617 | * This call is required to be made to register an individual tty device |
---|
3618 | * if the tty driver's flags have the TTY_DRIVER_DYNAMIC_DEV bit set. If |
---|
3619 | * that bit is not set, this function should not be called by a tty |
---|
3620 | * driver. |
---|
3621 | * |
---|
3622 | * Locking: ?? |
---|
3623 | */ |
---|
3624 | |
---|
3625 | struct class_device *tty_register_device(struct tty_driver *driver, |
---|
3626 | unsigned index, struct device *device) |
---|
3627 | { |
---|
3628 | char name[64]; |
---|
3629 | dev_t dev = MKDEV(driver->major, driver->minor_start) + index; |
---|
3630 | |
---|
3631 | if (index >= driver->num) { |
---|
3632 | printk(KERN_ERR "Attempt to register invalid tty line number " |
---|
3633 | " (%d).\n", index); |
---|
3634 | return ERR_PTR(-EINVAL); |
---|
3635 | } |
---|
3636 | |
---|
3637 | if (driver->type == TTY_DRIVER_TYPE_PTY) |
---|
3638 | pty_line_name(driver, index, name); |
---|
3639 | else |
---|
3640 | tty_line_name(driver, index, name); |
---|
3641 | |
---|
3642 | return class_device_create(tty_class, NULL, dev, device, "%s", name); |
---|
3643 | } |
---|
3644 | |
---|
3645 | /** |
---|
3646 | * tty_unregister_device - unregister a tty device |
---|
3647 | * @driver: the tty driver that describes the tty device |
---|
3648 | * @index: the index in the tty driver for this tty device |
---|
3649 | * |
---|
3650 | * If a tty device is registered with a call to tty_register_device() then |
---|
3651 | * this function must be called when the tty device is gone. |
---|
3652 | * |
---|
3653 | * Locking: ?? |
---|
3654 | */ |
---|
3655 | |
---|
3656 | void tty_unregister_device(struct tty_driver *driver, unsigned index) |
---|
3657 | { |
---|
3658 | class_device_destroy(tty_class, MKDEV(driver->major, driver->minor_start) + index); |
---|
3659 | } |
---|
3660 | |
---|
3661 | EXPORT_SYMBOL(tty_register_device); |
---|
3662 | EXPORT_SYMBOL(tty_unregister_device); |
---|
3663 | |
---|
3664 | struct tty_driver *alloc_tty_driver(int lines) |
---|
3665 | { |
---|
3666 | struct tty_driver *driver; |
---|
3667 | |
---|
3668 | driver = kmalloc(sizeof(struct tty_driver), GFP_KERNEL); |
---|
3669 | if (driver) { |
---|
3670 | memset(driver, 0, sizeof(struct tty_driver)); |
---|
3671 | driver->magic = TTY_DRIVER_MAGIC; |
---|
3672 | driver->num = lines; |
---|
3673 | /* later we'll move allocation of tables here */ |
---|
3674 | } |
---|
3675 | return driver; |
---|
3676 | } |
---|
3677 | |
---|
3678 | void put_tty_driver(struct tty_driver *driver) |
---|
3679 | { |
---|
3680 | kfree(driver); |
---|
3681 | } |
---|
3682 | |
---|
3683 | void tty_set_operations(struct tty_driver *driver, struct tty_operations *op) |
---|
3684 | { |
---|
3685 | driver->open = op->open; |
---|
3686 | driver->close = op->close; |
---|
3687 | driver->write = op->write; |
---|
3688 | driver->put_char = op->put_char; |
---|
3689 | driver->flush_chars = op->flush_chars; |
---|
3690 | driver->write_room = op->write_room; |
---|
3691 | driver->chars_in_buffer = op->chars_in_buffer; |
---|
3692 | driver->ioctl = op->ioctl; |
---|
3693 | driver->set_termios = op->set_termios; |
---|
3694 | driver->throttle = op->throttle; |
---|
3695 | driver->unthrottle = op->unthrottle; |
---|
3696 | driver->stop = op->stop; |
---|
3697 | driver->start = op->start; |
---|
3698 | driver->hangup = op->hangup; |
---|
3699 | driver->break_ctl = op->break_ctl; |
---|
3700 | driver->flush_buffer = op->flush_buffer; |
---|
3701 | driver->set_ldisc = op->set_ldisc; |
---|
3702 | driver->wait_until_sent = op->wait_until_sent; |
---|
3703 | driver->send_xchar = op->send_xchar; |
---|
3704 | driver->read_proc = op->read_proc; |
---|
3705 | driver->write_proc = op->write_proc; |
---|
3706 | driver->tiocmget = op->tiocmget; |
---|
3707 | driver->tiocmset = op->tiocmset; |
---|
3708 | } |
---|
3709 | |
---|
3710 | |
---|
3711 | EXPORT_SYMBOL(alloc_tty_driver); |
---|
3712 | EXPORT_SYMBOL(put_tty_driver); |
---|
3713 | EXPORT_SYMBOL(tty_set_operations); |
---|
3714 | |
---|
3715 | /* |
---|
3716 | * Called by a tty driver to register itself. |
---|
3717 | */ |
---|
3718 | int tty_register_driver(struct tty_driver *driver) |
---|
3719 | { |
---|
3720 | int error; |
---|
3721 | int i; |
---|
3722 | dev_t dev; |
---|
3723 | void **p = NULL; |
---|
3724 | |
---|
3725 | if (driver->flags & TTY_DRIVER_INSTALLED) |
---|
3726 | return 0; |
---|
3727 | |
---|
3728 | if (!(driver->flags & TTY_DRIVER_DEVPTS_MEM)) { |
---|
3729 | p = kmalloc(driver->num * 3 * sizeof(void *), GFP_KERNEL); |
---|
3730 | if (!p) |
---|
3731 | return -ENOMEM; |
---|
3732 | memset(p, 0, driver->num * 3 * sizeof(void *)); |
---|
3733 | } |
---|
3734 | |
---|
3735 | if (!driver->major) { |
---|
3736 | error = alloc_chrdev_region(&dev, driver->minor_start, driver->num, |
---|
3737 | (char*)driver->name); |
---|
3738 | if (!error) { |
---|
3739 | driver->major = MAJOR(dev); |
---|
3740 | driver->minor_start = MINOR(dev); |
---|
3741 | } |
---|
3742 | } else { |
---|
3743 | dev = MKDEV(driver->major, driver->minor_start); |
---|
3744 | error = register_chrdev_region(dev, driver->num, |
---|
3745 | (char*)driver->name); |
---|
3746 | } |
---|
3747 | if (error < 0) { |
---|
3748 | kfree(p); |
---|
3749 | return error; |
---|
3750 | } |
---|
3751 | |
---|
3752 | if (p) { |
---|
3753 | driver->ttys = (struct tty_struct **)p; |
---|
3754 | driver->termios = (struct termios **)(p + driver->num); |
---|
3755 | driver->termios_locked = (struct termios **)(p + driver->num * 2); |
---|
3756 | } else { |
---|
3757 | driver->ttys = NULL; |
---|
3758 | driver->termios = NULL; |
---|
3759 | driver->termios_locked = NULL; |
---|
3760 | } |
---|
3761 | |
---|
3762 | cdev_init(&driver->cdev, &tty_fops); |
---|
3763 | driver->cdev.owner = driver->owner; |
---|
3764 | error = cdev_add(&driver->cdev, dev, driver->num); |
---|
3765 | if (error) { |
---|
3766 | unregister_chrdev_region(dev, driver->num); |
---|
3767 | driver->ttys = NULL; |
---|
3768 | driver->termios = driver->termios_locked = NULL; |
---|
3769 | kfree(p); |
---|
3770 | return error; |
---|
3771 | } |
---|
3772 | |
---|
3773 | if (!driver->put_char) |
---|
3774 | driver->put_char = tty_default_put_char; |
---|
3775 | |
---|
3776 | list_add(&driver->tty_drivers, &tty_drivers); |
---|
3777 | |
---|
3778 | if ( !(driver->flags & TTY_DRIVER_DYNAMIC_DEV) ) { |
---|
3779 | for(i = 0; i < driver->num; i++) |
---|
3780 | tty_register_device(driver, i, NULL); |
---|
3781 | } |
---|
3782 | proc_tty_register_driver(driver); |
---|
3783 | return 0; |
---|
3784 | } |
---|
3785 | |
---|
3786 | EXPORT_SYMBOL(tty_register_driver); |
---|
3787 | |
---|
3788 | /* |
---|
3789 | * Called by a tty driver to unregister itself. |
---|
3790 | */ |
---|
3791 | int tty_unregister_driver(struct tty_driver *driver) |
---|
3792 | { |
---|
3793 | int i; |
---|
3794 | struct termios *tp; |
---|
3795 | void *p; |
---|
3796 | |
---|
3797 | if (driver->refcount) |
---|
3798 | return -EBUSY; |
---|
3799 | |
---|
3800 | unregister_chrdev_region(MKDEV(driver->major, driver->minor_start), |
---|
3801 | driver->num); |
---|
3802 | |
---|
3803 | list_del(&driver->tty_drivers); |
---|
3804 | |
---|
3805 | /* |
---|
3806 | * Free the termios and termios_locked structures because |
---|
3807 | * we don't want to get memory leaks when modular tty |
---|
3808 | * drivers are removed from the kernel. |
---|
3809 | */ |
---|
3810 | for (i = 0; i < driver->num; i++) { |
---|
3811 | tp = driver->termios[i]; |
---|
3812 | if (tp) { |
---|
3813 | driver->termios[i] = NULL; |
---|
3814 | kfree(tp); |
---|
3815 | } |
---|
3816 | tp = driver->termios_locked[i]; |
---|
3817 | if (tp) { |
---|
3818 | driver->termios_locked[i] = NULL; |
---|
3819 | kfree(tp); |
---|
3820 | } |
---|
3821 | if (!(driver->flags & TTY_DRIVER_DYNAMIC_DEV)) |
---|
3822 | tty_unregister_device(driver, i); |
---|
3823 | } |
---|
3824 | p = driver->ttys; |
---|
3825 | proc_tty_unregister_driver(driver); |
---|
3826 | driver->ttys = NULL; |
---|
3827 | driver->termios = driver->termios_locked = NULL; |
---|
3828 | kfree(p); |
---|
3829 | cdev_del(&driver->cdev); |
---|
3830 | return 0; |
---|
3831 | } |
---|
3832 | |
---|
3833 | EXPORT_SYMBOL(tty_unregister_driver); |
---|
3834 | |
---|
3835 | |
---|
3836 | /* |
---|
3837 | * Initialize the console device. This is called *early*, so |
---|
3838 | * we can't necessarily depend on lots of kernel help here. |
---|
3839 | * Just do some early initializations, and do the complex setup |
---|
3840 | * later. |
---|
3841 | */ |
---|
3842 | void __init console_init(void) |
---|
3843 | { |
---|
3844 | initcall_t *call; |
---|
3845 | |
---|
3846 | /* Setup the default TTY line discipline. */ |
---|
3847 | (void) tty_register_ldisc(N_TTY, &tty_ldisc_N_TTY); |
---|
3848 | |
---|
3849 | /* |
---|
3850 | * set up the console device so that later boot sequences can |
---|
3851 | * inform about problems etc.. |
---|
3852 | */ |
---|
3853 | #ifdef CONFIG_EARLY_PRINTK |
---|
3854 | disable_early_printk(); |
---|
3855 | #endif |
---|
3856 | call = __con_initcall_start; |
---|
3857 | while (call < __con_initcall_end) { |
---|
3858 | (*call)(); |
---|
3859 | call++; |
---|
3860 | } |
---|
3861 | } |
---|
3862 | |
---|
3863 | #ifdef CONFIG_VT |
---|
3864 | extern int vty_init(void); |
---|
3865 | #endif |
---|
3866 | |
---|
3867 | static int __init tty_class_init(void) |
---|
3868 | { |
---|
3869 | tty_class = class_create(THIS_MODULE, "tty"); |
---|
3870 | if (IS_ERR(tty_class)) |
---|
3871 | return PTR_ERR(tty_class); |
---|
3872 | return 0; |
---|
3873 | } |
---|
3874 | |
---|
3875 | postcore_initcall(tty_class_init); |
---|
3876 | |
---|
3877 | /* 3/2004 jmc: why do these devices exist? */ |
---|
3878 | |
---|
3879 | static struct cdev tty_cdev, console_cdev; |
---|
3880 | #ifdef CONFIG_UNIX98_PTYS |
---|
3881 | static struct cdev ptmx_cdev; |
---|
3882 | #endif |
---|
3883 | #ifdef CONFIG_VT |
---|
3884 | static struct cdev vc0_cdev; |
---|
3885 | #endif |
---|
3886 | |
---|
3887 | /* |
---|
3888 | * Ok, now we can initialize the rest of the tty devices and can count |
---|
3889 | * on memory allocations, interrupts etc.. |
---|
3890 | */ |
---|
3891 | static int __init tty_init(void) |
---|
3892 | { |
---|
3893 | cdev_init(&tty_cdev, &tty_fops); |
---|
3894 | if (cdev_add(&tty_cdev, MKDEV(TTYAUX_MAJOR, 0), 1) || |
---|
3895 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 0), 1, "/dev/tty") < 0) |
---|
3896 | panic("Couldn't register /dev/tty driver\n"); |
---|
3897 | class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 0), NULL, "tty"); |
---|
3898 | |
---|
3899 | cdev_init(&console_cdev, &console_fops); |
---|
3900 | if (cdev_add(&console_cdev, MKDEV(TTYAUX_MAJOR, 1), 1) || |
---|
3901 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 1), 1, "/dev/console") < 0) |
---|
3902 | panic("Couldn't register /dev/console driver\n"); |
---|
3903 | class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 1), NULL, "console"); |
---|
3904 | |
---|
3905 | #ifdef CONFIG_UNIX98_PTYS |
---|
3906 | cdev_init(&ptmx_cdev, &ptmx_fops); |
---|
3907 | if (cdev_add(&ptmx_cdev, MKDEV(TTYAUX_MAJOR, 2), 1) || |
---|
3908 | register_chrdev_region(MKDEV(TTYAUX_MAJOR, 2), 1, "/dev/ptmx") < 0) |
---|
3909 | panic("Couldn't register /dev/ptmx driver\n"); |
---|
3910 | class_device_create(tty_class, NULL, MKDEV(TTYAUX_MAJOR, 2), NULL, "ptmx"); |
---|
3911 | #endif |
---|
3912 | |
---|
3913 | #ifdef CONFIG_VT |
---|
3914 | if (!console_use_vt) |
---|
3915 | goto out_vt; |
---|
3916 | cdev_init(&vc0_cdev, &console_fops); |
---|
3917 | if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) || |
---|
3918 | register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0) |
---|
3919 | panic("Couldn't register /dev/tty0 driver\n"); |
---|
3920 | class_device_create(tty_class, NULL, MKDEV(TTY_MAJOR, 0), NULL, "tty0"); |
---|
3921 | |
---|
3922 | vty_init(); |
---|
3923 | out_vt: |
---|
3924 | #endif |
---|
3925 | return 0; |
---|
3926 | } |
---|
3927 | module_init(tty_init); |
---|