handle devtmpfs nodes

UDev follows the kernel given name, and re-uses the kernel created
device node. If the kernel and spcecified udev rules disagree, the
udev specified node node is created and the kernel-created on is
deleted.

5 files changed, 82 insertions, 32 deletions

diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 92b2d18b83..8e29efff86 100644
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -37,6 +37,7 @@ struct udev_device {
 	char *action;
 	char *devpath_old;
 	char *physdevpath;
+	char *knodename;
 	char **envp;
 	char *monitor_buf;
 	size_t monitor_buf_len;
@@ -208,6 +209,8 @@ int udev_device_read_uevent_file(struct udev_device *udev_device)
 			maj = strtoull(&line[6], NULL, 10);
 		else if (strncmp(line, "MINOR=", 6) == 0)
 			min = strtoull(&line[6], NULL, 10);
+		else if (strncmp(line, "DEVNAME=", 8) == 0)
+			udev_device_set_knodename(udev_device, &line[8]);
 
 		udev_device_add_property_from_string(udev_device, line);
 	}
@@ -621,6 +624,7 @@ void udev_device_unref(struct udev_device *udev_device)
 	free(udev_device->action);
 	free(udev_device->driver);
 	free(udev_device->devpath_old);
+	free(udev_device->knodename);
 	free(udev_device->physdevpath);
 	udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
 	free(udev_device->envp);
@@ -1175,6 +1179,19 @@ int udev_device_set_devpath_old(struct udev_device *udev_device, const char *dev
 	return 0;
 }
 
+const char *udev_device_get_knodename(struct udev_device *udev_device)
+{
+	return udev_device->knodename;
+}
+
+int udev_device_set_knodename(struct udev_device *udev_device, const char *knodename)
+{
+	udev_device->knodename = strdup(knodename);
+	if (udev_device->knodename == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
 const char *udev_device_get_physdevpath(struct udev_device *udev_device)
 {
 	return udev_device->physdevpath;
diff --git a/udev/lib/libudev-monitor.c b/udev/lib/libudev-monitor.c
index c87ff7434f..fc904c4a7c 100644
--- a/udev/lib/libudev-monitor.c
+++ b/udev/lib/libudev-monitor.c
@@ -445,6 +445,7 @@ struct udev_device *udev_monitor_receive_device(struct udev_monitor *udev_monito
 	int action_set = 0;
 	int maj = 0;
 	int min = 0;
+	int is_kernel = 0;
 
 retry:
 	if (udev_monitor == NULL)
@@ -480,9 +481,12 @@ retry:
 			info(udev_monitor->udev, "unicast netlink message ignored\n");
 			return NULL;
 		}
-		if ((snl.nl_groups == UDEV_MONITOR_KERNEL) && (snl.nl_pid > 0)) {
-			info(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", snl.nl_pid);
-			return NULL;
+		if (snl.nl_groups == UDEV_MONITOR_KERNEL) {
+			if (snl.nl_pid > 0) {
+				info(udev_monitor->udev, "multicast kernel netlink message from pid %d ignored\n", snl.nl_pid);
+				return NULL;
+			}
+			is_kernel = 1;
 		}
 	}
 
@@ -551,7 +555,10 @@ retry:
 		} else if (strncmp(key, "DEVTYPE=", 8) == 0) {
 			udev_device_set_devtype(udev_device, &key[8]);
 		} else if (strncmp(key, "DEVNAME=", 8) == 0) {
-			udev_device_set_devnode(udev_device, &key[8]);
+			if (is_kernel)
+				udev_device_set_knodename(udev_device, &key[8]);
+			else
+				udev_device_set_devnode(udev_device, &key[8]);
 		} else if (strncmp(key, "DEVLINKS=", 9) == 0) {
 			char devlinks[UTIL_PATH_SIZE];
 			char *slink;
@@ -586,7 +593,7 @@ retry:
 		} else if (strncmp(key, "TIMEOUT=", 8) == 0) {
 			udev_device_set_timeout(udev_device, strtoull(&key[8], NULL, 10));
 		} else if (strncmp(key, "PHYSDEV", 7) == 0) {
-			/* skip deprecated values */
+			/* suppress deprecated values */
 			continue;
 		} else {
 			udev_device_add_property_from_string(udev_device, key);
diff --git a/udev/lib/libudev-private.h b/udev/lib/libudev-private.h
index b283ff4ac3..8723cd7914 100644
--- a/udev/lib/libudev-private.h
+++ b/udev/lib/libudev-private.h
@@ -62,6 +62,8 @@ int udev_device_set_action(struct udev_device *udev_device, const char *action);
 int udev_device_set_driver(struct udev_device *udev_device, const char *driver);
 const char *udev_device_get_devpath_old(struct udev_device *udev_device);
 int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old);
+const char *udev_device_get_knodename(struct udev_device *udev_device);
+int udev_device_set_knodename(struct udev_device *udev_device, const char *knodename);
 const char *udev_device_get_physdevpath(struct udev_device *udev_device);
 int udev_device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath);
 int udev_device_get_timeout(struct udev_device *udev_device);
diff --git a/udev/udev-event.c b/udev/udev-event.c
index b7cdbf3402..345fb20e22 100644
--- a/udev/udev-event.c
+++ b/udev/udev-event.c
@@ -354,12 +354,24 @@ found:
 
 				if (event->tmp_node != NULL) {
 					util_strlcat(string, event->tmp_node, maxsize);
-					dbg(event->udev, "return existing temporary node\n");
+					dbg(event->udev, "tempnode: return earlier created one\n");
 					break;
 				}
 				devnum = udev_device_get_devnum(dev);
-				if (major(udev_device_get_devnum(dev) == 0))
+				if (major(devnum) == 0)
 					break;
+				/* lookup kernel provided node */
+				if (udev_device_get_knodename(dev) != NULL) {
+					util_strlcpy(filename, udev_get_dev_path(event->udev), sizeof(filename));
+					util_strlcat(filename, "/", sizeof(filename));
+					util_strlcat(filename, udev_device_get_knodename(dev), sizeof(filename));
+					if (stat(filename, &statbuf) == 0 && statbuf.st_rdev == devnum) {
+						util_strlcat(string, filename, maxsize);
+						dbg(event->udev, "tempnode: return kernel node\n");
+						break;
+					}
+				}
+				/* lookup /dev/{char,block}/<maj>:<min> */
 				if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
 					devtype = "block";
 				else
@@ -370,10 +382,11 @@ found:
 					 minor(udev_device_get_devnum(dev)));
 				if (stat(filename, &statbuf) == 0 && statbuf.st_rdev == devnum) {
 					util_strlcat(string, filename, maxsize);
-					dbg(event->udev, "return existing temporary node\n");
+					dbg(event->udev, "tempnode: return maj:min node\n");
 					break;
 				}
-				dbg(event->udev, "create temporary node\n");
+				/* create temporary node */
+				dbg(event->udev, "tempnode: create temp node\n");
 				asprintf(&event->tmp_node, "%s/.tmp-%s-%u:%u",
 					 udev_get_dev_path(event->udev), devtype,
 					 major(udev_device_get_devnum(dev)),
@@ -547,6 +560,7 @@ int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules)
 	    (strcmp(udev_device_get_action(dev), "add") == 0 || strcmp(udev_device_get_action(dev), "change") == 0)) {
 		char filename[UTIL_PATH_SIZE];
 		struct udev_device *dev_old;
+		int delete_kdevnode = 0;
 
 		dbg(event->udev, "device node add '%s'\n", udev_device_get_devpath(dev));
 
@@ -562,7 +576,7 @@ int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules)
 
 		udev_rules_apply_to_event(rules, event);
 		if (event->tmp_node != NULL) {
-			dbg(event->udev, "removing temporary device node\n");
+			dbg(event->udev, "cleanup temporary device node\n");
 			util_unlink_secure(event->udev, event->tmp_node);
 			free(event->tmp_node);
 			event->tmp_node = NULL;
@@ -570,33 +584,38 @@ int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules)
 
 		if (event->ignore_device) {
 			info(event->udev, "device event will be ignored\n");
+			delete_kdevnode = 1;
 			goto exit_add;
 		}
 
 		if (event->name != NULL && event->name[0] == '\0') {
 			info(event->udev, "device node creation supressed\n");
+			delete_kdevnode = 1;
 			goto exit_add;
 		}
 
+		/* if rule given name disagrees with kernel node name, delete kernel node */
+		if (event->name != NULL && udev_device_get_knodename(dev) != NULL) {
+			if (strcmp(event->name, udev_device_get_knodename(dev)) != 0)
+				delete_kdevnode = 1;
+		}
+
+		/* no rule, use kernel provided name */
 		if (event->name == NULL) {
-			const char *devname;
-
-			devname = udev_device_get_property_value(event->dev, "DEVNAME");
-			if (devname != NULL) {
-				info(event->udev, "no node name set, will use "
-				     "kernel supplied name '%s'\n", devname);
-				event->name = strdup(devname);
-				if (event->name == NULL)
-					goto exit_add;
+			if (udev_device_get_knodename(dev) != NULL) {
+				event->name = strdup(udev_device_get_knodename(dev));
+				info(event->udev, "no node name set, will use kernel supplied name '%s'\n", event->name);
+			} else {
+				event->name = strdup(udev_device_get_sysname(event->dev));
+				info(event->udev, "no node name set, will use device name '%s'\n", event->name);
 			}
 		}
+
+		/* something went wrong */
 		if (event->name == NULL) {
-			info(event->udev, "no node name set, will use device name '%s'\n",
-			     udev_device_get_sysname(event->dev));
-			event->name = strdup(udev_device_get_sysname(event->dev));
-		}
-		if (event->name == NULL)
+			err(event->udev, "no node name for '%s'\n", udev_device_get_sysname(event->dev));
 			goto exit_add;
+		}
 
 		/* set device node name */
 		util_strlcpy(filename, udev_get_dev_path(event->udev), sizeof(filename));
@@ -614,6 +633,18 @@ int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules)
 		/* create new node and symlinks */
 		err = udev_node_add(dev, event->mode, event->uid, event->gid);
 exit_add:
+		if (delete_kdevnode && udev_device_get_knodename(dev) != NULL) {
+			struct stat stats;
+
+			util_strlcpy(filename, udev_get_dev_path(event->udev), sizeof(filename));
+			util_strlcat(filename, "/", sizeof(filename));
+			util_strlcat(filename, udev_device_get_knodename(dev), sizeof(filename));
+			if (stat(filename, &stats) == 0 && stats.st_rdev == udev_device_get_devnum(dev)) {
+				unlink(filename);
+				util_delete_path(event->udev, filename);
+				info(event->udev, "removed kernel created node '%s'\n", filename);
+			}
+		}
 		udev_device_unref(dev_old);
 		goto exit;
 	}
diff --git a/udev/udev-node.c b/udev/udev-node.c
index 322e0b88de..2f9cf4d7ac 100644
--- a/udev/udev-node.c
+++ b/udev/udev-node.c
@@ -68,7 +68,6 @@ static int name_index(struct udev *udev, const char *devpath, const char *name,
 int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mode_t mode, uid_t uid, gid_t gid)
 {
 	struct udev *udev = udev_device_get_udev(dev);
-	char filename[UTIL_PATH_SIZE];
 	struct stat stats;
 	int preserve = 0;
 	int err = 0;
@@ -81,14 +80,8 @@ int udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mod
 	else
 		mode |= S_IFCHR;
 
-	if (file == NULL) {
+	if (file == NULL)
 		file = udev_device_get_devnode(dev);
-	} else if (file[0] != '/') {
-		util_strlcpy(filename, udev_get_dev_path(udev), sizeof(filename));
-		util_strlcat(filename, "/", sizeof(filename));
-		util_strlcat(filename, file, sizeof(filename));
-		file = filename;
-	}
 
 	if (lstat(file, &stats) == 0) {
 		if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {