1 | /* |
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2 | * xs_api.c |
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3 | * |
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4 | * blocktap interface functions to xenstore |
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5 | * |
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6 | * (c) 2005 Andrew Warfield and Julian Chesterfield |
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7 | * |
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8 | * |
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9 | * This program is free software; you can redistribute it and/or |
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10 | * modify it under the terms of the GNU General Public License version 2 |
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11 | * as published by the Free Software Foundation; or, when distributed |
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12 | * separately from the Linux kernel or incorporated into other |
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13 | * software packages, subject to the following license: |
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14 | * |
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15 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
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16 | * of this source file (the "Software"), to deal in the Software without |
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17 | * restriction, including without limitation the rights to use, copy, modify, |
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18 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, |
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19 | * and to permit persons to whom the Software is furnished to do so, subject to |
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20 | * the following conditions: |
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21 | * |
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22 | * The above copyright notice and this permission notice shall be included in |
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23 | * all copies or substantial portions of the Software. |
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24 | * |
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25 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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26 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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27 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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28 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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29 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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30 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
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31 | * IN THE SOFTWARE. |
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32 | * |
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33 | */ |
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34 | |
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35 | #include <stdio.h> |
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36 | #include <stdlib.h> |
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37 | #include <printf.h> |
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38 | #include <string.h> |
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39 | #include <err.h> |
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40 | #include <stdarg.h> |
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41 | #include <errno.h> |
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42 | #include <xs.h> |
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43 | #include <sys/types.h> |
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44 | #include <sys/stat.h> |
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45 | #include <fcntl.h> |
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46 | #include <poll.h> |
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47 | #include "blktaplib.h" |
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48 | #include "list.h" |
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49 | #include "xs_api.h" |
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50 | |
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51 | #if 0 |
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52 | #define DPRINTF(_f, _a...) printf ( _f , ## _a ) |
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53 | #else |
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54 | #define DPRINTF(_f, _a...) ((void)0) |
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55 | #endif |
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56 | |
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57 | static LIST_HEAD(watches); |
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58 | #define BASE_DEV_VAL 2048 |
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59 | |
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60 | int xs_gather(struct xs_handle *xs, const char *dir, ...) |
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61 | { |
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62 | va_list ap; |
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63 | const char *name; |
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64 | char *path, **e; |
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65 | int ret = 0, num,i; |
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66 | unsigned int len; |
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67 | xs_transaction_t xth; |
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68 | |
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69 | again: |
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70 | if ( (xth = xs_transaction_start(xs)) == XBT_NULL) { |
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71 | DPRINTF("unable to start xs trasanction\n"); |
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72 | ret = ENOMEM; |
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73 | return ret; |
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74 | } |
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75 | |
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76 | va_start(ap, dir); |
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77 | while ( (ret == 0) && (name = va_arg(ap, char *)) != NULL) { |
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78 | const char *fmt = va_arg(ap, char *); |
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79 | void *result = va_arg(ap, void *); |
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80 | char *p; |
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81 | |
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82 | if (asprintf(&path, "%s/%s", dir, name) == -1) |
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83 | { |
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84 | printf("allocation error in xs_gather!\n"); |
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85 | ret = ENOMEM; |
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86 | break; |
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87 | } |
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88 | |
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89 | p = xs_read(xs, xth, path, &len); |
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90 | |
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91 | |
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92 | free(path); |
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93 | if (p == NULL) { |
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94 | ret = ENOENT; |
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95 | break; |
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96 | } |
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97 | if (fmt) { |
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98 | if (sscanf(p, fmt, result) == 0) |
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99 | ret = EINVAL; |
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100 | free(p); |
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101 | } else |
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102 | *(char **)result = p; |
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103 | } |
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104 | va_end(ap); |
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105 | |
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106 | if (!xs_transaction_end(xs, xth, ret)) { |
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107 | if (ret == 0 && errno == EAGAIN) |
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108 | goto again; |
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109 | else |
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110 | ret = errno; |
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111 | } |
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112 | |
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113 | return ret; |
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114 | } |
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115 | |
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116 | |
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117 | /* Single printf and write: returns -errno or 0. */ |
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118 | int xs_printf(struct xs_handle *h, const char *dir, const char *node, |
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119 | const char *fmt, ...) |
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120 | { |
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121 | char *buf, *path; |
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122 | va_list ap; |
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123 | int ret; |
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124 | |
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125 | va_start(ap, fmt); |
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126 | ret = vasprintf(&buf, fmt, ap); |
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127 | va_end(ap); |
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128 | |
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129 | asprintf(&path, "%s/%s", dir, node); |
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130 | |
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131 | if ((path == NULL) || (buf == NULL)) |
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132 | return 0; |
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133 | |
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134 | ret = xs_write(h, XBT_NULL, path, buf, strlen(buf)+1); |
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135 | |
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136 | free(buf); |
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137 | free(path); |
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138 | |
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139 | return ret; |
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140 | } |
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141 | |
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142 | |
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143 | int xs_exists(struct xs_handle *h, const char *path) |
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144 | { |
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145 | char **d; |
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146 | unsigned int num; |
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147 | xs_transaction_t xth; |
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148 | |
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149 | if ( (xth = xs_transaction_start(h)) == XBT_NULL) { |
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150 | printf("unable to start xs trasanction\n"); |
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151 | return 0; |
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152 | } |
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153 | |
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154 | d = xs_directory(h, xth, path, &num); |
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155 | xs_transaction_end(h, xth, 0); |
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156 | if (d == NULL) |
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157 | return 0; |
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158 | free(d); |
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159 | return 1; |
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160 | } |
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161 | |
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162 | |
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163 | |
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164 | /** |
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165 | * This assumes that the domain name we are looking for is unique. |
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166 | * Name parameter Domain-0 |
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167 | */ |
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168 | char *get_dom_domid(struct xs_handle *h) |
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169 | { |
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170 | char **e, *val, *domid = NULL; |
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171 | unsigned int num, len; |
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172 | int i; |
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173 | char *path; |
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174 | xs_transaction_t xth; |
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175 | |
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176 | if ( (xth = xs_transaction_start(h)) == XBT_NULL) { |
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177 | warn("unable to start xs trasanction\n"); |
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178 | return NULL; |
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179 | } |
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180 | |
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181 | e = xs_directory(h, xth, "/local/domain", &num); |
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182 | if (e == NULL) |
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183 | return NULL; |
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184 | |
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185 | for (i = 0; (i < num) && (domid == NULL); i++) { |
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186 | asprintf(&path, "/local/domain/%s/name", e[i]); |
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187 | val = xs_read(h, xth, path, &len); |
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188 | free(path); |
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189 | if (val == NULL) |
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190 | continue; |
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191 | |
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192 | if (strcmp(val, DOMNAME) == 0) { |
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193 | /* match! */ |
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194 | asprintf(&path, "/local/domain/%s/domid", e[i]); |
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195 | domid = xs_read(h, xth, path, &len); |
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196 | free(path); |
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197 | } |
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198 | free(val); |
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199 | } |
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200 | xs_transaction_end(h, xth, 0); |
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201 | |
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202 | free(e); |
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203 | return domid; |
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204 | } |
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205 | |
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206 | int convert_dev_name_to_num(char *name) { |
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207 | char *p_sd, *p_hd, *p_xvd, *p_plx, *p, *alpha,*ptr; |
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208 | int majors[10] = {3,22,33,34,56,57,88,89,90,91}; |
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209 | int maj,i,ret = 0; |
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210 | |
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211 | asprintf(&p_sd,"/dev/sd"); |
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212 | asprintf(&p_hd,"/dev/hd"); |
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213 | asprintf(&p_xvd,"/dev/xvd"); |
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214 | asprintf(&p_plx,"plx"); |
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215 | asprintf(&alpha,"abcdefghijklmnop"); |
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216 | |
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217 | |
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218 | if (strstr(name, p_sd) != NULL) { |
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219 | p = name + strlen(p_sd); |
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220 | for(i = 0, ptr = alpha; i < strlen(alpha); i++) { |
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221 | if(*ptr == *p) |
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222 | break; |
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223 | *ptr++; |
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224 | } |
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225 | *p++; |
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226 | ret = BASE_DEV_VAL + (16*i) + atoi(p); |
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227 | } else if (strstr(name, p_hd) != NULL) { |
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228 | p = name + strlen(p_hd); |
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229 | for (i = 0, ptr = alpha; i < strlen(alpha); i++) { |
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230 | if(*ptr == *p) break; |
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231 | *ptr++; |
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232 | } |
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233 | *p++; |
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234 | ret = (majors[i/2]*256) + atoi(p); |
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235 | |
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236 | } else if (strstr(name, p_xvd) != NULL) { |
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237 | p = name + strlen(p_xvd); |
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238 | for(i = 0, ptr = alpha; i < strlen(alpha); i++) { |
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239 | if(*ptr == *p) break; |
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240 | *ptr++; |
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241 | } |
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242 | *p++; |
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243 | ret = (202*256) + (16*i) + atoi(p); |
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244 | |
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245 | } else if (strstr(name, p_plx) != NULL) { |
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246 | p = name + strlen(p_plx); |
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247 | ret = atoi(p); |
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248 | |
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249 | } else { |
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250 | DPRINTF("Unknown device type, setting to default.\n"); |
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251 | ret = BASE_DEV_VAL; |
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252 | } |
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253 | |
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254 | free(p_sd); |
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255 | free(p_hd); |
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256 | free(p_xvd); |
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257 | free(p_plx); |
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258 | free(alpha); |
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259 | |
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260 | return ret; |
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261 | } |
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262 | |
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263 | /** |
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264 | * A little paranoia: we don't just trust token. |
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265 | */ |
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266 | static struct xenbus_watch *find_watch(const char *token) |
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267 | { |
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268 | struct xenbus_watch *i, *cmp; |
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269 | |
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270 | cmp = (void *)strtoul(token, NULL, 16); |
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271 | |
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272 | list_for_each_entry(i, &watches, list) |
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273 | if (i == cmp) |
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274 | return i; |
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275 | return NULL; |
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276 | } |
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277 | |
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278 | /** |
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279 | * Register callback to watch this node. |
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280 | * like xs_watch, return 0 on failure |
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281 | */ |
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282 | int register_xenbus_watch(struct xs_handle *h, struct xenbus_watch *watch) |
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283 | { |
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284 | /* Pointer in ascii is the token. */ |
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285 | char token[sizeof(watch) * 2 + 1]; |
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286 | |
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287 | sprintf(token, "%lX", (long)watch); |
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288 | if (find_watch(token)) { |
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289 | DPRINTF("watch collision!\n"); |
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290 | return -EINVAL; |
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291 | } |
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292 | |
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293 | if (!xs_watch(h, watch->node, token)) { |
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294 | DPRINTF("unable to set watch!\n"); |
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295 | return -EINVAL; |
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296 | } |
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297 | |
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298 | list_add(&watch->list, &watches); |
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299 | |
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300 | return 0; |
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301 | } |
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302 | |
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303 | int unregister_xenbus_watch(struct xs_handle *h, struct xenbus_watch *watch) |
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304 | { |
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305 | char token[sizeof(watch) * 2 + 1]; |
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306 | |
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307 | sprintf(token, "%lX", (long)watch); |
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308 | if (!find_watch(token)) { |
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309 | DPRINTF("no such watch!\n"); |
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310 | return -EINVAL; |
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311 | } |
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312 | |
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313 | if (!xs_unwatch(h, watch->node, token)) |
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314 | DPRINTF("XENBUS Failed to release watch %s\n", |
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315 | watch->node); |
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316 | |
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317 | list_del(&watch->list); |
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318 | |
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319 | return 0; |
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320 | } |
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321 | |
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322 | /** |
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323 | * Re-register callbacks to all watches. |
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324 | */ |
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325 | void reregister_xenbus_watches(struct xs_handle *h) |
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326 | { |
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327 | struct xenbus_watch *watch; |
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328 | char token[sizeof(watch) * 2 + 1]; |
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329 | |
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330 | list_for_each_entry(watch, &watches, list) { |
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331 | sprintf(token, "%lX", (long)watch); |
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332 | xs_watch(h, watch->node, token); |
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333 | } |
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334 | } |
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335 | |
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336 | /** |
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337 | * based on watch_thread() |
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338 | */ |
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339 | int xs_fire_next_watch(struct xs_handle *h) |
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340 | { |
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341 | char **res; |
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342 | char *token; |
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343 | char *node = NULL; |
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344 | struct xenbus_watch *w; |
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345 | int er; |
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346 | unsigned int num; |
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347 | |
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348 | res = xs_read_watch(h, &num); |
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349 | if (res == NULL) |
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350 | return -EAGAIN; /* in O_NONBLOCK, read_watch returns 0... */ |
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351 | |
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352 | node = res[XS_WATCH_PATH]; |
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353 | token = res[XS_WATCH_TOKEN]; |
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354 | |
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355 | w = find_watch(token); |
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356 | if (w) |
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357 | w->callback(h, w, node); |
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358 | |
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359 | free(res); |
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360 | |
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361 | return 1; |
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362 | } |
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