chiark / gitweb /
change database file names
authorKay Sievers <kay.sievers@vrfy.org>
Wed, 19 Aug 2009 18:49:49 +0000 (20:49 +0200)
committerKay Sievers <kay.sievers@vrfy.org>
Wed, 19 Aug 2009 18:49:49 +0000 (20:49 +0200)
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

NEWS
TODO
libudev/libudev-device-private.c
libudev/libudev-device.c
libudev/libudev-private.h
libudev/libudev-queue-private.c
test/udev-test.pl
udev/udev-event.c
udev/udev-node.c

diff --git a/NEWS b/NEWS
index 28321c5..daefed8 100644 (file)
--- 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 6a47536..5df63fa 100644 (file)
--- 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
index 68dc0a5..80a4da4 100644 (file)
 #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);
 }
index eac6bd6..22d8349 100644 (file)
@@ -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;
index 16f9f2e..b735298 100644 (file)
@@ -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);
index 4dea4ad..e0a8738 100644 (file)
@@ -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));
index 79ed247..aaeec24 100755 (executable)
@@ -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
        },
        {
index f3c2bd2..3a6c71a 100644 (file)
@@ -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 */
index 03ab0ea..36f6f6d 100644 (file)
 #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));
        }