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-rw-r--r--src/udev/udev-watch.c161
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);
+}