more readlink buffer size handling

[elogind.git] / udev / udev-watch.c

diff --git a/udev/udev-watch.c b/udev/udev-watch.c
index 53492e5f357fd2fcb73128af2a95721fd55bd99b..5fa60101c46ad63cb99e444d4b103c6f5d33217c 100644 (file)
--- a/udev/udev-watch.c
+++ b/udev/udev-watch.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2004-2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2004-2010 Kay Sievers <kay.sievers@vrfy.org>
  * Copyright (C) 2009 Canonical Ltd.
  * Copyright (C) 2009 Scott James Remnant <scott@netsplit.com>
  *
@@ -26,27 +26,22 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#ifdef HAVE_INOTIFY
 #include <sys/inotify.h>
-#endif
 
 #include "udev.h"
 
-int inotify_fd = -1;
+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
  */
-void udev_watch_init(struct udev *udev)
+int udev_watch_init(struct udev *udev)
 {
-       inotify_fd = inotify_init();
-       if (inotify_fd >= 0)
-               util_set_fd_cloexec(inotify_fd);
-       else if (errno == ENOSYS)
-               info(udev, "unable to use inotify, udevd will not monitor rule files changes\n");
-       else
+       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
@@ -77,29 +72,29 @@ void udev_watch_restore(struct udev *udev)
                        size_t l;
                        ssize_t len;
                        struct udev_device *dev;
+                       int maj, min;
+                       char type;
 
-                       if (ent->d_name[0] < '0' || ent->d_name[0] > '9')
+                       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) {
-                               unlinkat(dirfd(dir), ent->d_name, 0);
-                               continue;
-                       }
+                       if (len <= 0 || len == (ssize_t)l)
+                               goto unlink;
                        s[len] = '\0';
-                       dbg(udev, "old watch to '%s' found\n", device);
-                       dev = udev_device_new_from_syspath(udev, device);
-                       if (dev == NULL) {
-                               unlinkat(dirfd(dir), ent->d_name, 0);
-                               continue;
-                       }
+
+                       if (sscanf(s, "%c%i:%i", &type, &maj, &min) != 3)
+                               goto unlink;
+                       dev = udev_device_new_from_devnum(udev, type, makedev(maj, min));
+                       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);
                }
 
@@ -114,6 +109,7 @@ void udev_watch_restore(struct udev *udev)
 void udev_watch_begin(struct udev *udev, struct udev_device *dev)
 {
        char filename[UTIL_PATH_SIZE];
+       char majmin[UTIL_PATH_SIZE];
        int wd;
 
        if (inotify_fd < 0)
@@ -124,12 +120,16 @@ void udev_watch_begin(struct udev *udev, struct udev_device *dev)
        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(majmin, sizeof(majmin), "%c%i:%i",
+                strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
+                major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
        snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);
        util_create_path(udev, filename);
        unlink(filename);
-       symlink(udev_device_get_devpath(dev), filename);
+       symlink(majmin, filename);
 
        udev_device_set_watch_handle(dev, wd);
 }
@@ -158,20 +158,27 @@ void udev_watch_end(struct udev *udev, struct udev_device *dev)
 struct udev_device *udev_watch_lookup(struct udev *udev, int wd)
 {
        char filename[UTIL_PATH_SIZE];
-       char syspath[UTIL_PATH_SIZE];
+       char majmin[UTIL_PATH_SIZE];
        char *s;
        size_t l;
        ssize_t len;
+       int maj, min;
+       char type;
+       dev_t devnum;
 
        if (inotify_fd < 0 || wd < 0)
                return NULL;
 
        snprintf(filename, sizeof(filename), "%s/.udev/watch/%d", udev_get_dev_path(udev), wd);
-       s = syspath;
-       l = util_strpcpy(&s, sizeof(syspath), udev_get_sys_path(udev));
+       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)
+       if (len <= 0 || (size_t)len == l)
                return NULL;
        s[len] = '\0';
-       return udev_device_new_from_syspath(udev, syspath);
+
+       if (sscanf(s, "%c%i:%i", &type, &maj, &min) != 3)
+               return NULL;
+       devnum = makedev(maj, min);
+       return udev_device_new_from_devnum(udev, type, devnum);
 }