diff options
Diffstat (limited to 'src/udev/udev-watch.c')
| -rw-r--r-- | src/udev/udev-watch.c | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/src/udev/udev-watch.c b/src/udev/udev-watch.c new file mode 100644 index 0000000000..311f5bdf23 --- /dev/null +++ b/src/udev/udev-watch.c @@ -0,0 +1,161 @@ +/* + * Copyright (C) 2004-2012 Kay Sievers <kay@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_init1(IN_CLOEXEC); + if (inotify_fd < 0) + log_error("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) +{ + if (inotify_fd < 0) + return; + + if (rename("/run/udev/watch", "/run/udev/watch.old") == 0) { + DIR *dir; + struct dirent *ent; + + dir = opendir("/run/udev/watch.old"); + if (dir == NULL) { + log_error("unable to open old watches dir /run/udev/watch.old; old watches will not be restored: %m"); + return; + } + + for (ent = readdir(dir); ent != NULL; ent = readdir(dir)) { + char device[UTIL_PATH_SIZE]; + ssize_t len; + struct udev_device *dev; + + if (ent->d_name[0] == '.') + continue; + + len = readlinkat(dirfd(dir), ent->d_name, device, sizeof(device)); + if (len <= 0 || len == (ssize_t)sizeof(device)) + goto unlink; + device[len] = '\0'; + + dev = udev_device_new_from_device_id(udev, device); + if (dev == NULL) + goto unlink; + + log_debug("restoring old watch on '%s'\n", udev_device_get_devnode(dev)); + udev_watch_begin(udev, dev); + udev_device_unref(dev); +unlink: + unlinkat(dirfd(dir), ent->d_name, 0); + } + + closedir(dir); + rmdir("/run/udev/watch.old"); + + } else if (errno != ENOENT) { + log_error("unable to move watches dir /run/udev/watch; old watches will not be restored: %m"); + } +} + +void udev_watch_begin(struct udev *udev, struct udev_device *dev) +{ + char filename[UTIL_PATH_SIZE]; + int wd; + int r; + + if (inotify_fd < 0) + return; + + log_debug("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) { + log_error("inotify_add_watch(%d, %s, %o) failed: %m\n", + inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE); + return; + } + + snprintf(filename, sizeof(filename), "/run/udev/watch/%d", wd); + mkdir_parents(filename, 0755); + unlink(filename); + r = symlink(udev_device_get_id_filename(dev), filename); + if (r < 0) + log_error("Failed to create symlink: %m"); + + 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; + + log_debug("removing watch on '%s'\n", udev_device_get_devnode(dev)); + inotify_rm_watch(inotify_fd, wd); + + snprintf(filename, sizeof(filename), "/run/udev/watch/%d", 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 device[UTIL_NAME_SIZE]; + ssize_t len; + + if (inotify_fd < 0 || wd < 0) + return NULL; + + snprintf(filename, sizeof(filename), "/run/udev/watch/%d", wd); + len = readlink(filename, device, sizeof(device)); + if (len <= 0 || (size_t)len == sizeof(device)) + return NULL; + device[len] = '\0'; + + return udev_device_new_from_device_id(udev, device); +} |