~ubuntu-branches/ubuntu/karmic/udev/karmic-proposed

/*

 * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>

 * Copyright (C) 2009 Canonical Ltd.

 * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <sys/types.h>

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <dirent.h>

#include <stddef.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/inotify.h>

#include "udev.h"

static int inotify_fd = -1;

/* inotify descriptor, will be shared with rules directory;

 * set to cloexec since we need our children to be able to add

 * watches for us

 */

int udev_watch_init(struct udev *udev)

{

	inotify_fd = inotify_init();

	if (inotify_fd >= 0)

		util_set_fd_cloexec(inotify_fd);

	else

		err(udev, "inotify_init failed: %m\n");

	return inotify_fd;

}

/* move any old watches directory out of the way, and then restore

 * the watches

 */

void udev_watch_restore(struct udev *udev)

{

	char filename[UTIL_PATH_SIZE], oldname[UTIL_PATH_SIZE];

	if (inotify_fd < 0)

		return;

	util_strscpyl(oldname, sizeof(oldname), udev_get_dev_path(udev), "/.udev/watch.old", NULL);

	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/watch", NULL);

	if (rename(filename, oldname) == 0) {

		DIR *dir;

		struct dirent *ent;

		dir = opendir(oldname);

		if (dir == NULL) {

			err(udev, "unable to open old watches dir '%s', old watches will not be restored: %m", oldname);

			return;

		}

		for (ent = readdir(dir); ent != NULL; ent = readdir(dir)) {

			char device[UTIL_PATH_SIZE];

			char *s;

			size_t l;

			ssize_t len;

			struct udev_device *dev;

			if (ent->d_name[0] < '0' || ent->d_name[0] > '9')

				continue;

			s = device;

			l = util_strpcpy(&s, sizeof(device), udev_get_sys_path(udev));

			len = readlinkat(dirfd(dir), ent->d_name, s, l);

			if (len <= 0 || len >= (ssize_t)l) {

				unlinkat(dirfd(dir), ent->d_name, 0);

				continue;

			}

			s[len] = '\0';

			dbg(udev, "old watch to '%s' found\n", device);

			dev = udev_device_new_from_syspath(udev, device);

			if (dev == NULL) {

				unlinkat(dirfd(dir), ent->d_name, 0);

				continue;

			}

			info(udev, "restoring old watch on '%s'\n", udev_device_get_devnode(dev));

			udev_watch_begin(udev, dev);

			udev_device_unref(dev);

			unlinkat(dirfd(dir), ent->d_name, 0);

		}

		closedir(dir);

		rmdir(oldname);

	} else if (errno != ENOENT) {

		err(udev, "unable to move watches dir '%s', old watches will not be restored: %m", filename);

	}

}

void udev_watch_begin(struct udev *udev, struct udev_device *dev)

{

	char filename[UTIL_PATH_SIZE];

	int wd;

	if (inotify_fd < 0)

		return;

	info(udev, "adding watch on '%s'\n", udev_device_get_devnode(dev));

	wd = inotify_add_watch(inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);

	if (wd < 0) {

		err(udev, "inotify_add_watch(%d, %s, %o) failed: %m\n",

		    inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE);

		return;

	}

	snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);

	util_create_path(udev, filename);

	unlink(filename);

	symlink(udev_device_get_devpath(dev), filename);

	udev_device_set_watch_handle(dev, wd);

}

void udev_watch_end(struct udev *udev, struct udev_device *dev)

{

	int wd;

	char filename[UTIL_PATH_SIZE];

	if (inotify_fd < 0)

		return;

	wd = udev_device_get_watch_handle(dev);

	if (wd < 0)

		return;

	info(udev, "removing watch on '%s'\n", udev_device_get_devnode(dev));

	inotify_rm_watch(inotify_fd, wd);

	snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);

	unlink(filename);

	udev_device_set_watch_handle(dev, -1);

}

struct udev_device *udev_watch_lookup(struct udev *udev, int wd)

{

	char filename[UTIL_PATH_SIZE];

	char syspath[UTIL_PATH_SIZE];

	char *s;

	size_t l;

	ssize_t len;

	if (inotify_fd < 0 || wd < 0)

		return NULL;

	snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);

	s = syspath;

	l = util_strpcpy(&s, sizeof(syspath), udev_get_sys_path(udev));

	len = readlink(filename, s, l);

	if (len < 0 || (size_t)len >= l)

		return NULL;

	s[len] = '\0';

	return udev_device_new_from_syspath(udev, syspath);

}