X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=src%2Fudev%2Fudev-watch.c;fp=src%2Fudev%2Fudev-watch.c;h=228d18fedf4935707abaa20f11c558004f2dfca7;hb=3e2147858f21943d5f4a781c60f33ac22c6096ed;hp=0000000000000000000000000000000000000000;hpb=19c5f19d69bb5f520fa7213239490c55de06d99d;p=elogind.git

diff --git a/src/udev/udev-watch.c b/src/udev/udev-watch.c
new file mode 100644
index 000000000..228d18fed
--- /dev/null
+++ b/src/udev/udev-watch.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2004-2010 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_init1(IN_CLOEXEC);
+        if (inotify_fd < 0)
+                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_run_path(udev), "/watch.old", NULL);
+        util_strscpyl(filename, sizeof(filename), udev_get_run_path(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] == '.')
+                                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)
+                                goto unlink;
+                        s[len] = '\0';
+
+                        dev = udev_device_new_from_id_filename(udev, s);
+                        if (dev == NULL)
+                                goto unlink;
+
+                        info(udev, "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(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/watch/%d", udev_get_run_path(udev), wd);
+        util_create_path(udev, filename);
+        unlink(filename);
+        symlink(udev_device_get_id_filename(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/watch/%d", udev_get_run_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 majmin[UTIL_PATH_SIZE];
+        char *s;
+        size_t l;
+        ssize_t len;
+
+        if (inotify_fd < 0 || wd < 0)
+                return NULL;
+
+        snprintf(filename, sizeof(filename), "%s/watch/%d", udev_get_run_path(udev), wd);
+        s = majmin;
+        l = util_strpcpy(&s, sizeof(majmin), 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_id_filename(udev, s);
+}