/* * 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 <errno.h> #include <stdio.h> #include <dirent.h> #include <stddef.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_errno(errno, "inotify_init failed: %m"); 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_errno(errno, "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'", 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_errno(errno, "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'", udev_device_get_devnode(dev)); wd = inotify_add_watch(inotify_fd, udev_device_get_devnode(dev), IN_CLOSE_WRITE); if (wd < 0) { log_error_errno(errno, "inotify_add_watch(%d, %s, %o) failed: %m", 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_errno(errno, "Failed to create symlink %s: %m", 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; log_debug("removing watch on '%s'", 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); }