source: trunk/packages/xen-3.1/xen-3.1/linux-2.6-xen-sparse/drivers/xen/balloon/sysfs.c @ 34

/******************************************************************************
 * balloon/sysfs.c
 *
 * Xen balloon driver - sysfs interfaces.
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/sysdev.h>
#include "common.h"

#ifdef HAVE_XEN_PLATFORM_COMPAT_H
#include <xen/platform-compat.h>
#endif

#define BALLOON_CLASS_NAME "memory"

#define BALLOON_SHOW(name, format, args...)                     \
        static ssize_t show_##name(struct sys_device *dev,      \
                                   char *buf)                   \
        {                                                       \
                return sprintf(buf, format, ##args);            \
        }                                                       \
        static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)

BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(bs.current_pages));
BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(bs.balloon_low));
BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(bs.balloon_high));
BALLOON_SHOW(hard_limit_kb,
             (bs.hard_limit!=~0UL) ? "%lu\n" : "???\n",
             (bs.hard_limit!=~0UL) ? PAGES2KB(bs.hard_limit) : 0);
BALLOON_SHOW(driver_kb, "%lu\n", PAGES2KB(bs.driver_pages));

static ssize_t show_target_kb(struct sys_device *dev, char *buf)
{
        return sprintf(buf, "%lu\n", PAGES2KB(bs.target_pages));
}

static ssize_t store_target_kb(struct sys_device *dev,
                               const char *buf,
                               size_t count)
{
        char memstring[64], *endchar;
        unsigned long long target_bytes;

        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
        
        if (count <= 1)
                return -EBADMSG; /* runt */
        if (count > sizeof(memstring))
                return -EFBIG;   /* too long */
        strcpy(memstring, buf);
        
        target_bytes = memparse(memstring, &endchar);
        balloon_set_new_target(target_bytes >> PAGE_SHIFT);
        
        return count;
}

static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
                   show_target_kb, store_target_kb);

static struct sysdev_attribute *balloon_attrs[] = {
        &attr_target_kb,
};

static struct attribute *balloon_info_attrs[] = {
        &attr_current_kb.attr,
        &attr_low_kb.attr,
        &attr_high_kb.attr,
        &attr_hard_limit_kb.attr,
        &attr_driver_kb.attr,
        NULL
};

static struct attribute_group balloon_info_group = {
        .name = "info",
        .attrs = balloon_info_attrs,
};

static struct sysdev_class balloon_sysdev_class = {
        set_kset_name(BALLOON_CLASS_NAME),
};

static struct sys_device balloon_sysdev;

static int register_balloon(struct sys_device *sysdev)
{
        int i, error;

        error = sysdev_class_register(&balloon_sysdev_class);
        if (error)
                return error;

        sysdev->id = 0;
        sysdev->cls = &balloon_sysdev_class;

        error = sysdev_register(sysdev);
        if (error) {
                sysdev_class_unregister(&balloon_sysdev_class);
                return error;
        }

        for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
                error = sysdev_create_file(sysdev, balloon_attrs[i]);
                if (error)
                        goto fail;
        }

        error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
        if (error)
                goto fail;
        
        return 0;

 fail:
        while (--i >= 0)
                sysdev_remove_file(sysdev, balloon_attrs[i]);
        sysdev_unregister(sysdev);
        sysdev_class_unregister(&balloon_sysdev_class);
        return error;
}

static void unregister_balloon(struct sys_device *sysdev)
{
        int i;

        sysfs_remove_group(&sysdev->kobj, &balloon_info_group);
        for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++)
                sysdev_remove_file(sysdev, balloon_attrs[i]);
        sysdev_unregister(sysdev);
        sysdev_class_unregister(&balloon_sysdev_class);
}

int balloon_sysfs_init(void)
{
        return register_balloon(&balloon_sysdev);
}

void balloon_sysfs_exit(void)
{
        unregister_balloon(&balloon_sysdev);
}