replace utimes() with utimensat()

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

diff --git a/udev/udev-node.c b/udev/udev-node.c
index 3685485eb1066a113226733e366aa5eeb0160f3c..307a76b2712c2cf9f8849e4f2f7ef1f4eab20c88 100644 (file)
--- a/udev/udev-node.c
+++ b/udev/udev-node.c
@@ -25,6 +25,7 @@
 #include <errno.h>
 #include <grp.h>
 #include <dirent.h>
+#include <sys/time.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -55,6 +56,8 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
                        info(udev, "preserve file '%s', because it has correct dev_t\n", file);
                        preserve = 1;
                        udev_selinux_lsetfilecon(udev, file, mode);
+                       /* update time stamp when we re-use the node, like on media change events */
+                       utimensat(AT_FDCWD, file, NULL, 0);
                } else {
                        char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
 
@@ -77,10 +80,16 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
                }
        } else {
                info(udev, "mknod(%s, %#o, (%u,%u))\n", file, mode, major(devnum), minor(devnum));
-               util_create_path(udev, file);
-               udev_selinux_setfscreatecon(udev, file, mode);
-               err = mknod(file, mode, devnum);
-               udev_selinux_resetfscreatecon(udev);
+               do {
+                       err = util_create_path(udev, file);
+                       if (err != 0 && err != -ENOENT)
+                               break;
+                       udev_selinux_setfscreatecon(udev, file, mode);
+                       err = mknod(file, mode, devnum);
+                       if (err != 0)
+                               err = -errno;
+                       udev_selinux_resetfscreatecon(udev);
+               } while (err == -ENOENT);
                if (err != 0) {
                        err(udev, "mknod(%s, %#o, (%u,%u) failed: %m\n", file, mode, major(devnum), minor(devnum));
                        goto exit;
@@ -169,16 +178,23 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
                                        info(udev, "preserve already existing symlink '%s' to '%s'\n",
                                             slink, target);
                                        udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
+                                       utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
                                        goto exit;
                                }
                        }
                }
        } else {
                info(udev, "creating symlink '%s' to '%s'\n", slink, target);
-               util_create_path(udev, slink);
-               udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
-               err = symlink(target, slink);
-               udev_selinux_resetfscreatecon(udev);
+               do {
+                       err = util_create_path(udev, slink);
+                       if (err != 0 && err != -ENOENT)
+                               break;
+                       udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
+                       err = symlink(target, slink);
+                       if (err != 0)
+                               err = -errno;
+                       udev_selinux_resetfscreatecon(udev);
+               } while (err == -ENOENT);
                if (err == 0)
                        goto exit;
        }
@@ -186,10 +202,16 @@ static int node_symlink(struct udev *udev, const char *node, const char *slink)
        info(udev, "atomically replace '%s'\n", slink);
        util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
        unlink(slink_tmp);
-       util_create_path(udev, slink);
-       udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
-       err = symlink(target, slink_tmp);
-       udev_selinux_resetfscreatecon(udev);
+       do {
+               err = util_create_path(udev, slink_tmp);
+               if (err != 0 && err != -ENOENT)
+                       break;
+               udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
+               err = symlink(target, slink_tmp);
+               if (err != 0)
+                       err = -errno;
+               udev_selinux_resetfscreatecon(udev);
+       } while (err == -ENOENT);
        if (err != 0) {
                err(udev, "symlink(%s, %s) failed: %m\n", target, slink_tmp);
                goto exit;
@@ -263,6 +285,7 @@ static const char *link_find_prioritized(struct udev_device *dev, bool add, cons
                        udev_device_unref(dev_db);
                }
        }
+       closedir(dir);
        return target;
 }
 
@@ -301,9 +324,17 @@ static void link_update(struct udev_device *dev, const char *slink, bool add)
        }
 
        if (add) {
+               int err;
+
                dbg(udev, "creating index: '%s'\n", filename);
-               util_create_path(udev, filename);
-               symlink(udev_device_get_devpath(dev), filename);
+               do {
+                       err = util_create_path(udev, filename);
+                       if (err != 0 && err != -ENOENT)
+                               break;
+                       err = symlink(udev_device_get_devpath(dev), filename);
+                       if (err != 0)
+                               err = -errno;
+               } while (err == -ENOENT);
        }
 }
 
@@ -391,10 +422,11 @@ int udev_node_remove(struct udev_device *dev)
        const char *devnode;
        char partitionname[UTIL_PATH_SIZE];
        struct stat stats;
+       struct udev_device *dev_check;
        int err = 0;
        int num;
 
-       /* remove,update symlinks, remove symlinks from name index */
+       /* remove/update symlinks, remove symlinks from name index */
        udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
                link_update(dev, udev_list_entry_get_name(list_entry), 0);
 
@@ -410,10 +442,15 @@ int udev_node_remove(struct udev_device *dev)
                return -1;
        }
 
-       info(udev, "removing device node '%s'\n", devnode);
-       err = util_unlink_secure(udev, devnode);
-       if (err)
-               return err;
+       dev_check = udev_device_new_from_syspath(udev, udev_device_get_syspath(dev));
+       if (dev_check != NULL && stats.st_rdev == udev_device_get_devnum(dev_check)) {
+               /* do not remove device node if the same sys-device is re-created in the meantime */
+               info(udev, "keeping device node of existing device'%s'\n", devnode);
+       } else {
+               info(udev, "removing device node '%s'\n", devnode);
+               err = util_unlink_secure(udev, devnode);
+       }
+       udev_device_unref(dev_check);
 
        num = udev_device_get_num_fake_partitions(dev);
        if (num > 0) {