change database file names

With very deeply nested devices, We can not use a single file
name to carry an entire DEVPATH. Use <subsystem>:<sysname> as
the database filename, which should also simplify the handling
of devices moving around, as these values will not change but
still be unique.

For the name stack we use the <maj>:<min> now as the filename.

> On Tue, Aug 18, 2009 at 09:59:56AM -0400, Ric Wheeler wrote:
> The first is that udev grumbles during boot about "file name too long"
> like the following:
>
> Aug 17 06:49:58 megadeth udevd-event[20447]: unable to create db file
> '/dev/.udev/db/\x2fdevices\x2fpci0000:00\x2f0000:00:04.0\x2f0000:17:00.0\x2f0000:18:0a.0\x2f0000:1f:00.0\x2fhost11\x2fport-11:0\x2fexpander-11:0\x2fport-11:0:0\x2fexpander-11:1\x2fport-11:1:0\x2fexpander-11:2\x2fport-11:2:17\x2fexpander-11:3\x2fport-11:3:1\x2fend_device-11:3:1\x2fbsg\x2fend_device-11:3:1':
> File name too long

9 files changed, 100 insertions, 68 deletions

diff --git a/NEWS b/NEWS
index 28321c5109..daefed8812 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,17 @@ udev 147
 ========
 Bugfixes.
 
+To support DEVPATH strings larger than the maximum file name length, the
+private udev database format has changed. If some software still reads the
+private files in /dev/.udev/, which it shouldn't, now it's time to fix it.
+Please do not port anything to the new format again, everything in /dev/.udev
+is and always was private to udev, and may and will change any time without
+prior notice.
+
+NAME="%k" causes a warning now. It's is and always was completely superfluous.
+It will break kernel supplied DEVNAMEs and therefore it needs to be removed
+from all rules.
+
 udev 146
 ========
 Bugfixes.
diff --git a/TODO b/TODO
index 6a475365be..5df63fad05 100644
--- a/TODO
+++ b/TODO
@@ -1,4 +1,12 @@
 
+  o drop support for node names in name stack, support only symlinks
+     With well defined and kernel-supplied node names, we no longer need
+     to support a possible stack of conflicting symlinks and node names.
+     From there on, only symlinks with identical names can be claimed
+     by multiple devices. It will simplify the logic a lot and shrink
+     /dev/.udev/names/ significantly. Also exclude "*/MAJ:MIN" link names
+     from the name stack, they can not conflict.
+  o remove most NAME= rules (they are provided by the 2.6.31 kernel)
   o get rid of braindead "scan all devices to find myself" libusb interface
       if it can not be fixed, drop libusb entirely
   o convert firmware.sh to C
diff --git a/libudev/libudev-device-private.c b/libudev/libudev-device-private.c
index 68dc0a5b98..80a4da4c96 100644
--- a/libudev/libudev-device-private.c
+++ b/libudev/libudev-device-private.c
@@ -21,16 +21,6 @@
 #include "libudev.h"
 #include "libudev-private.h"
 
-static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
-{
-	char *s;
-	size_t l;
-
-	s = filename;
-	l = util_strpcpyl(&s, len, udev_get_dev_path(udev), "/.udev/db/", NULL);
-	return util_path_encode(devpath, s, l);
-}
-
 int udev_device_update_db(struct udev_device *udev_device)
 {
 	struct udev *udev = udev_device_get_udev(udev_device);
@@ -43,8 +33,8 @@ int udev_device_update_db(struct udev_device *udev_device)
 	struct udev_list_entry *list_entry;
 	int ret;
 
-	devpath_to_db_path(udev, udev_device_get_devpath(udev_device), filename, sizeof(filename));
-	util_create_path(udev, filename);
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 	unlink(filename);
 
 	udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device))
@@ -78,11 +68,13 @@ int udev_device_update_db(struct udev_device *udev_device)
 	}
 	info(udev, "create db link (%s)\n", target);
 	udev_selinux_setfscreatecon(udev, filename, S_IFLNK);
+	util_create_path(udev, filename);
 	ret = symlink(target, filename);
 	udev_selinux_resetfscreatecon(udev);
 	if (ret == 0)
 		goto out;
 file:
+	util_create_path(udev, filename);
 	f = fopen(filename, "w");
 	if (f == NULL) {
 		err(udev, "unable to create db file '%s': %m\n", filename);
@@ -122,18 +114,21 @@ int udev_device_delete_db(struct udev_device *udev_device)
 	struct udev *udev = udev_device_get_udev(udev_device);
 	char filename[UTIL_PATH_SIZE];
 
-	devpath_to_db_path(udev, udev_device_get_devpath(udev_device), filename, sizeof(filename));
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 	unlink(filename);
 	return 0;
 }
 
-int udev_device_rename_db(struct udev_device *udev_device, const char *devpath_old)
+int udev_device_rename_db(struct udev_device *udev_device)
 {
 	struct udev *udev = udev_device_get_udev(udev_device);
 	char filename_old[UTIL_PATH_SIZE];
 	char filename[UTIL_PATH_SIZE];
 
-	devpath_to_db_path(udev, devpath_old, filename_old, sizeof(filename_old));
-	devpath_to_db_path(udev, udev_device_get_devpath(udev_device), filename, sizeof(filename));
+	util_strscpyl(filename_old, sizeof(filename_old), udev_get_dev_path(udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname_old(udev_device), NULL);
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 	return rename(filename_old, filename);
 }
diff --git a/libudev/libudev-device.c b/libudev/libudev-device.c
index eac6bd6041..22d8349275 100644
--- a/libudev/libudev-device.c
+++ b/libudev/libudev-device.c
@@ -51,6 +51,7 @@ struct udev_device {
 	char *driver;
 	char *action;
 	char *devpath_old;
+	char *sysname_old;
 	char *knodename;
 	char **envp;
 	char *monitor_buf;
@@ -76,16 +77,6 @@ struct udev_device {
 	unsigned int ignore_remove:1;
 };
 
-static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
-{
-	char *s;
-	size_t l;
-
-	s = filename;
-	l = util_strpcpyl(&s, len, udev_get_dev_path(udev), "/.udev/db/", NULL);
-	return util_path_encode(devpath, s, l);
-}
-
 int udev_device_read_db(struct udev_device *udev_device)
 {
 	struct stat stats;
@@ -93,7 +84,8 @@ int udev_device_read_db(struct udev_device *udev_device)
 	char line[UTIL_LINE_SIZE];
 	FILE *f;
 
-	devpath_to_db_path(udev_device->udev, udev_device->devpath, filename, sizeof(filename));
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/.udev/db/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 
 	if (lstat(filename, &stats) != 0) {
 		dbg(udev_device->udev, "no db file to read %s: %m\n", filename);
@@ -677,6 +669,7 @@ 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->sysname_old);
 	free(udev_device->knodename);
 	udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
 	free(udev_device->envp);
@@ -1282,14 +1275,39 @@ 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 *pos;
+	size_t len;
+
 	free(udev_device->devpath_old);
 	udev_device->devpath_old = strdup(devpath_old);
 	if (udev_device->devpath_old == NULL)
 		return -ENOMEM;
 	udev_device_add_property(udev_device, "DEVPATH_OLD", udev_device->devpath_old);
+
+	pos = strrchr(udev_device->devpath_old, '/');
+	if (pos == NULL)
+		return -EINVAL;
+	udev_device->sysname_old = strdup(&pos[1]);
+	if (udev_device->sysname_old == NULL)
+		return -ENOMEM;
+
+	/* some devices have '!' in their name, change that to '/' */
+	len = 0;
+	while (udev_device->sysname_old[len] != '\0') {
+		if (udev_device->sysname_old[len] == '!')
+			udev_device->sysname_old[len] = '/';
+		len++;
+	}
 	return 0;
 }
 
+const char *udev_device_get_sysname_old(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->sysname_old;
+}
+
 const char *udev_device_get_knodename(struct udev_device *udev_device)
 {
 	return udev_device->knodename;
diff --git a/libudev/libudev-private.h b/libudev/libudev-private.h
index 16f9f2e1c1..b735298c67 100644
--- a/libudev/libudev-private.h
+++ b/libudev/libudev-private.h
@@ -79,6 +79,7 @@ int udev_device_read_uevent_file(struct udev_device *udev_device);
 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);
+const char *udev_device_get_sysname_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);
@@ -101,7 +102,7 @@ void udev_device_set_info_loaded(struct udev_device *device);
 /* libudev-device-private.c */
 int udev_device_update_db(struct udev_device *udev_device);
 int udev_device_delete_db(struct udev_device *udev_device);
-int udev_device_rename_db(struct udev_device *udev_device, const char *devpath);
+int udev_device_rename_db(struct udev_device *udev_device);
 
 /* libudev-monitor.c - netlink/unix socket communication  */
 int udev_monitor_disconnect(struct udev_monitor *udev_monitor);
@@ -186,8 +187,8 @@ int udev_queue_export_device_failed(struct udev_queue_export *udev_queue_export,
 
 /* libudev-util.c */
 #define UTIL_PATH_SIZE				1024
-#define UTIL_LINE_SIZE				2048
 #define UTIL_NAME_SIZE				512
+#define UTIL_LINE_SIZE				2048
 #define UDEV_ALLOWED_CHARS_INPUT		"/ $%?,"
 ssize_t util_get_sys_subsystem(struct udev *udev, const char *syspath, char *subsystem, size_t size);
 ssize_t util_get_sys_driver(struct udev *udev, const char *syspath, char *driver, size_t size);
diff --git a/libudev/libudev-queue-private.c b/libudev/libudev-queue-private.c
index 4dea4ad0e7..e0a8738e0e 100644
--- a/libudev/libudev-queue-private.c
+++ b/libudev/libudev-queue-private.c
@@ -396,16 +396,13 @@ static void update_failed(struct udev_queue_export *udev_queue_export,
 {
 	struct udev *udev = udev_device_get_udev(udev_device);
 	char filename[UTIL_PATH_SIZE];
-	char *s;
-	size_t l;
 
 	if (state != DEVICE_FAILED && udev_queue_export->failed_count == 0)
 		return;
 
 	/* location of failed file */
-	s = filename;
-	l = util_strpcpyl(&s, sizeof(filename), udev_get_dev_path(udev_queue_export->udev), "/.udev/failed/", NULL);
-	util_path_encode(udev_device_get_devpath(udev_device), s, l);
+	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev), "/.udev/failed/",
+		      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 
 	switch (state) {
 	case DEVICE_FAILED:
@@ -428,14 +425,13 @@ static void update_failed(struct udev_queue_export *udev_queue_export,
 		break;
 
 	case DEVICE_FINISHED:
-		if (udev_device_get_devpath_old(udev_device) != NULL) {
+		if (udev_device_get_sysname_old(udev_device) != NULL &&
+		    strcmp(udev_device_get_sysname_old(udev_device), udev_device_get_sysname(udev_device)) != 0) {
 			/* "move" event - rename failed file to current name, do not delete failed */
 			char filename_old[UTIL_PATH_SIZE];
 
-			s = filename_old;
-			l = util_strpcpyl(&s, sizeof(filename_old), udev_get_dev_path(udev_queue_export->udev), "/.udev/failed/", NULL);
-			util_path_encode(udev_device_get_devpath_old(udev_device), s, l);
-
+			util_strscpyl(filename_old, sizeof(filename_old), udev_get_dev_path(udev), "/.udev/failed/",
+				      udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname_old(udev_device), NULL);
 			if (rename(filename_old, filename) == 0)
 				info(udev, "renamed devpath, moved failed state of '%s' to %s'\n",
 				     udev_device_get_devpath_old(udev_device), udev_device_get_devpath(udev_device));
diff --git a/test/udev-test.pl b/test/udev-test.pl
index 79ed247d46..aaeec24955 100755
--- a/test/udev-test.pl
+++ b/test/udev-test.pl
@@ -819,9 +819,9 @@ EOF
 		subsys		=> "tty",
 		devpath		=> "/devices/pci0000:00/0000:00:1d.7/usb5/5-2/5-2:1.0/tty/ttyACM0",
 		exp_name	=> "symlink2-ttyACM0",
-		exp_target	=> "ttyACM0",
+		exp_target	=> "ttyACM-0",
 		rules		=> <<EOF
-KERNEL=="ttyACM[0-9]*", NAME="ttyACM%n", SYMLINK="symlink1-%n symlink2-%k symlink3-%b"
+KERNEL=="ttyACM[0-9]*", NAME="ttyACM-%n", SYMLINK="symlink1-%n symlink2-%k symlink3-%b"
 EOF
 	},
 	{
diff --git a/udev/udev-event.c b/udev/udev-event.c
index f3c2bd2225..3a6c71abe9 100644
--- a/udev/udev-event.c
+++ b/udev/udev-event.c
@@ -531,10 +531,12 @@ int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules)
 	struct udev_device *dev = event->dev;
 	int err = 0;
 
-	if (udev_device_get_devpath_old(dev) != NULL) {
-		if (udev_device_rename_db(dev, udev_device_get_devpath(dev)) == 0)
-			info(event->udev, "moved database from '%s' to '%s'\n",
-			     udev_device_get_devpath_old(dev), udev_device_get_devpath(dev));
+	if (udev_device_get_sysname_old(dev) != NULL &&
+	    strcmp(udev_device_get_sysname_old(dev), udev_device_get_sysname(dev)) != 0) {
+		udev_device_rename_db(dev);
+		info(event->udev, "moved database from '%s:%s' to '%s:%s'\n",
+		     udev_device_get_subsystem(dev), udev_device_get_sysname_old(dev),
+		     udev_device_get_subsystem(dev), udev_device_get_sysname(dev));
 	}
 
 	/* add device node */
diff --git a/udev/udev-node.c b/udev/udev-node.c
index 03ab0ea86f..36f6f6d993 100644
--- a/udev/udev-node.c
+++ b/udev/udev-node.c
@@ -32,24 +32,20 @@
 #define TMP_FILE_EXT		".udev-tmp"
 
 /* reverse mapping from the device file name to the devpath */
-static int name_index(struct udev *udev, const char *devpath, const char *name, int add)
+static int name_index(struct udev_device *dev, const char *name, int add)
 {
-	char devpath_enc[UTIL_PATH_SIZE];
+	struct udev *udev = udev_device_get_udev(dev);
 	char name_enc[UTIL_PATH_SIZE];
 	char filename[UTIL_PATH_SIZE * 2];
-	int fd;
 
 	util_path_encode(&name[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
-	util_path_encode(devpath, devpath_enc, sizeof(devpath_enc));
-	util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev),
-		      "/.udev/names/", name_enc, "/", devpath_enc, NULL);
+	snprintf(filename, sizeof(filename), "%s/.udev/names/%s/%u:%u", udev_get_dev_path(udev), name_enc,
+		 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
 
 	if (add) {
 		dbg(udev, "creating index: '%s'\n", filename);
 		util_create_path(udev, filename);
-		fd = open(filename, O_WRONLY|O_TRUNC|O_CREAT, 0644);
-		if (fd > 0)
-			close(fd);
+		symlink(udev_device_get_devpath(dev), filename);
 	} else {
 		dbg(udev, "removing index: '%s'\n", filename);
 		unlink(filename);
@@ -247,18 +243,23 @@ static int name_index_get_devices(struct udev *udev, const char *name, struct ud
 	dbg(udev, "found index directory '%s'\n", dirname);
 
 	while (1) {
-		struct dirent *ent;
-		char device[UTIL_PATH_SIZE];
+		struct dirent *dent;
+		char devpath[UTIL_PATH_SIZE];
+		char syspath[UTIL_PATH_SIZE];
+		int len;
 
-		ent = readdir(dir);
-		if (ent == NULL || ent->d_name[0] == '\0')
+		dent = readdir(dir);
+		if (dent == NULL || dent->d_name[0] == '\0')
 			break;
-		if (ent->d_name[0] == '.')
+		if (dent->d_name[0] == '.')
 			continue;
 
-		util_strscpyl(device, sizeof(device), udev_get_sys_path(udev), ent->d_name, NULL);
-		util_path_decode(device);
-		udev_list_entry_add(udev, dev_list, device, NULL, 1, 0);
+		len = readlinkat(dirfd(dir), dent->d_name, devpath, sizeof(devpath));
+		if (len < 0 || (size_t)len >= sizeof(devpath))
+			continue;
+		devpath[len] = '\0';
+		util_strscpyl(syspath, sizeof(syspath), udev_get_sys_path(udev), devpath, NULL);
+		udev_list_entry_add(udev, dev_list, syspath, NULL, 1, 0);
 		count++;
 	}
 	closedir(dir);
@@ -384,7 +385,7 @@ void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev
 
 		info(udev, "update old name, '%s' no longer belonging to '%s'\n",
 		     name, udev_device_get_devpath(dev));
-		name_index(udev, udev_device_get_devpath(dev), name, 0);
+		name_index(dev, name, 0);
 		update_link(dev, name);
 	}
 
@@ -398,7 +399,7 @@ void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev
 
 		if (devnode != NULL && strcmp(devnode_old, devnode) != 0) {
 			info(udev, "node has changed from '%s' to '%s'\n", devnode_old, devnode);
-			name_index(udev, udev_device_get_devpath(dev), devnode_old, 0);
+			name_index(dev, devnode_old, 0);
 			update_link(dev, devnode_old);
 		}
 	}
@@ -441,11 +442,11 @@ int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
 	}
 
 	/* add node to name index */
-	name_index(udev, udev_device_get_devpath(dev), udev_device_get_devnode(dev), 1);
+	name_index(dev, udev_device_get_devnode(dev), 1);
 
 	/* create/update symlinks, add symlinks to name index */
 	udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
-		name_index(udev, udev_device_get_devpath(dev), udev_list_entry_get_name(list_entry), 1);
+		name_index(dev, udev_list_entry_get_name(list_entry), 1);
 		update_link(dev, udev_list_entry_get_name(list_entry));
 	}
 exit:
@@ -463,11 +464,11 @@ int udev_node_remove(struct udev_device *dev)
 	int num;
 
 	/* remove node from name index */
-	name_index(udev, udev_device_get_devpath(dev), udev_device_get_devnode(dev), 0);
+	name_index(dev, udev_device_get_devnode(dev), 0);
 
 	/* remove,update symlinks, remove symlinks from name index */
 	udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
-		name_index(udev, udev_device_get_devpath(dev), udev_list_entry_get_name(list_entry), 0);
+		name_index(dev, udev_list_entry_get_name(list_entry), 0);
 		update_link(dev, udev_list_entry_get_name(list_entry));
 	}