1 files changed, 152 insertions, 0 deletions
diff --git a/src/grp-udev/libudev-core/udev-watch.c b/src/grp-udev/libudev-core/udev-watch.c
new file mode 100644
index 0000000000..ba3e7b979b
--- /dev/null
+++ b/src/grp-udev/libudev-core/udev-watch.c
@@ -0,0 +1,152 @@
+/*
+ * 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 <dirent.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/inotify.h>
+#include <unistd.h>
+
+#include "systemd-basic/stdio-util.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[sizeof("/run/udev/watch/") + DECIMAL_STR_MAX(int)];
+        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;
+        }
+
+        xsprintf(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[sizeof("/run/udev/watch/") + DECIMAL_STR_MAX(int)];
+
+        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);
+
+        xsprintf(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[sizeof("/run/udev/watch/") + DECIMAL_STR_MAX(int)];
+        char device[UTIL_NAME_SIZE];
+        ssize_t len;
+
+        if (inotify_fd < 0 || wd < 0)
+                return NULL;
+
+        xsprintf(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);
+}