store node name and symlinks into db symlink target if they are small enough

diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 8e4360a7f4c50a5d96f3d83646ce1251a75a9c6d..2113ebd43c431bbf9fe60cd4a8345492143aa9c8 100644 (file)
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -83,6 +83,7 @@ static int device_read_db(struct udev_device *udev_device)
        if ((stats.st_mode & S_IFMT) == S_IFLNK) {
                char target[UTIL_PATH_SIZE];
                int target_len;
+               char *next;
 
                target_len = readlink(filename, target, sizeof(target));
                if (target_len > 0)
@@ -91,8 +92,29 @@ static int device_read_db(struct udev_device *udev_device)
                        info(udev_device->udev, "error reading db link %s: %m\n", filename);
                        return -1;
                }
+
+               next = strchr(target, ' ');
+               if (next != NULL) {
+                       next[0] = '\0';
+                       next = &next[1];
+               }
                if (asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
                        return -ENOMEM;
+               while (next != NULL) {
+                       char linkname[UTIL_PATH_SIZE];
+                       const char *lnk;
+
+                       lnk = next;
+                       next = strchr(next, ' ');
+                       if (next != NULL) {
+                               next[0] = '\0';
+                               next = &next[1];
+                       }
+                       util_strlcpy(linkname, udev_get_dev_path(udev_device->udev), sizeof(linkname));
+                       util_strlcat(linkname, "/", sizeof(linkname));
+                       util_strlcat(linkname, next, sizeof(linkname));
+                       device_add_devlink(udev_device, linkname);
+               }
                info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
                return 0;
        }

diff --git a/udev/udev_db.c b/udev/udev_db.c
index 34bdef375398093070cf60545224e5e5de1821da..e03c2782a30bf3fd517b8baa7c32f48b09d3c3f8 100644 (file)
--- a/udev/udev_db.c
+++ b/udev/udev_db.c
@@ -127,6 +127,10 @@ int udev_db_rename(struct udev *udev, const char *devpath_old, const char *devpa
 int udev_db_add_device(struct udevice *udevice)
 {
        char filename[UTIL_PATH_SIZE];
+       FILE *f;
+       struct name_entry *name_loop;
+       char target[232]; /* on 64bit, tmpfs inlines up to 239 bytes */
+       int ret;
 
        if (udevice->test_run)
                return 0;
@@ -135,55 +139,61 @@ int udev_db_add_device(struct udevice *udevice)
        create_path(udevice->udev, filename);
        unlink(filename);
 
-       /*
-        * don't waste tmpfs memory pages, if we don't have any data to store
-        * create fake db-file; store the node-name in a symlink target
-        */
-       if (list_empty(&udevice->symlink_list) && list_empty(&udevice->env_list) &&
-           !udevice->partitions && !udevice->ignore_remove) {
-               int ret;
-               dbg(udevice->udev, "nothing interesting to store, create symlink\n");
-               udev_selinux_setfscreatecon(udevice->udev, filename, S_IFLNK);
-               ret = symlink(udevice->name, filename);
-               udev_selinux_resetfscreatecon(udevice->udev);
-               if (ret != 0) {
-                       err(udevice->udev, "unable to create db link '%s': %m\n", filename);
-                       return -1;
+       if (!list_empty(&udevice->env_list))
+               goto file;
+       if (udevice->partitions || udevice->ignore_remove)
+               goto file;
+       /* try not to waste tmpfs memory, store values, if they fit, in a symlink target */
+       util_strlcpy(target, udevice->name, sizeof(target));
+       list_for_each_entry(name_loop, &udevice->symlink_list, node) {
+               size_t len;
+
+               util_strlcat(target, " ", sizeof(target));
+               len = util_strlcat(target, name_loop->name, sizeof(target));
+               if (len >= sizeof(target)) {
+                       info(udevice->udev, "size of links too large, create file\n");
+                       goto file;
                }
-       } else {
-               FILE *f;
-               struct name_entry *name_loop;
-
-               f = fopen(filename, "w");
-               if (f == NULL) {
-                       err(udevice->udev, "unable to create db file '%s': %m\n", filename);
-                       return -1;
+       }
+       /* add symlink names to index */
+       list_for_each_entry(name_loop, &udevice->symlink_list, node) {
+               name_index(udevice->udev, udevice->dev->devpath, name_loop->name, 1);
+       }
+       info(udevice->udev, "create db link (%s)\n", target);
+       udev_selinux_setfscreatecon(udevice->udev, filename, S_IFLNK);
+       ret = symlink(target, filename);
+       udev_selinux_resetfscreatecon(udevice->udev);
+       if (ret == 0)
+               goto out;
+file:
+       f = fopen(filename, "w");
+       if (f == NULL) {
+               err(udevice->udev, "unable to create db file '%s': %m\n", filename);
+               return -1;
                }
-               dbg(udevice->udev, "storing data for device '%s' in '%s'\n", udevice->dev->devpath, filename);
+       info(udevice->udev, "created db file for '%s' in '%s'\n", udevice->dev->devpath, filename);
 
-               fprintf(f, "N:%s\n", udevice->name);
-               list_for_each_entry(name_loop, &udevice->symlink_list, node) {
-                       fprintf(f, "S:%s\n", name_loop->name);
-                       /* add symlink-name to index */
-                       name_index(udevice->udev, udevice->dev->devpath, name_loop->name, 1);
-               }
-               fprintf(f, "M:%u:%u\n", major(udevice->devt), minor(udevice->devt));
-               if (udevice->link_priority != 0)
-                       fprintf(f, "L:%u\n", udevice->link_priority);
-               if (udevice->event_timeout >= 0)
-                       fprintf(f, "T:%u\n", udevice->event_timeout);
-               if (udevice->partitions != 0)
-                       fprintf(f, "A:%u\n", udevice->partitions);
-               if (udevice->ignore_remove)
-                       fprintf(f, "R:%u\n", udevice->ignore_remove);
-               list_for_each_entry(name_loop, &udevice->env_list, node)
-                       fprintf(f, "E:%s\n", name_loop->name);
-               fclose(f);
+       fprintf(f, "N:%s\n", udevice->name);
+       list_for_each_entry(name_loop, &udevice->symlink_list, node) {
+               fprintf(f, "S:%s\n", name_loop->name);
+               /* add symlink names to index */
+               name_index(udevice->udev, udevice->dev->devpath, name_loop->name, 1);
        }
-
+       fprintf(f, "M:%u:%u\n", major(udevice->devt), minor(udevice->devt));
+       if (udevice->link_priority != 0)
+               fprintf(f, "L:%u\n", udevice->link_priority);
+       if (udevice->event_timeout >= 0)
+               fprintf(f, "T:%u\n", udevice->event_timeout);
+       if (udevice->partitions != 0)
+               fprintf(f, "A:%u\n", udevice->partitions);
+       if (udevice->ignore_remove)
+               fprintf(f, "R:%u\n", udevice->ignore_remove);
+       list_for_each_entry(name_loop, &udevice->env_list, node)
+               fprintf(f, "E:%s\n", name_loop->name);
+       fclose(f);
+out:
        /* add name to index */
        name_index(udevice->udev, udevice->dev->devpath, udevice->name, 1);
-
        return 0;
 }
 
@@ -209,8 +219,9 @@ int udev_db_get_device(struct udevice *udevice, const char *devpath)
        if ((stats.st_mode & S_IFMT) == S_IFLNK) {
                char target[UTIL_NAME_SIZE];
                int target_len;
+               char *next;
 
-               info(udevice->udev, "found a symlink as db file\n");
+               info(udevice->udev, "found db symlink\n");
                target_len = readlink(filename, target, sizeof(target));
                if (target_len > 0)
                        target[target_len] = '\0';
@@ -218,8 +229,25 @@ int udev_db_get_device(struct udevice *udevice, const char *devpath)
                        info(udevice->udev, "error reading db link %s: %m\n", filename);
                        return -1;
                }
-               dbg(udevice->udev, "db link points to '%s'\n", target);
+               next = strchr(target, ' ');
+               if (next != NULL) {
+                       next[0] = '\0';
+                       next = &next[1];
+               }
+               info(udevice->udev, "got db link node: '%s'\n", target);
                util_strlcpy(udevice->name, target, sizeof(udevice->name));
+               while (next != NULL) {
+                       char *lnk;
+
+                       lnk = next;
+                       next = strchr(next, ' ');
+                       if (next != NULL) {
+                               next[0] = '\0';
+                               next = &next[1];
+                       }
+                       info(udevice->udev, "got db link link: '%s'\n", lnk);
+                       name_list_add(udevice->udev, &udevice->symlink_list, lnk, 0);
+               }
                return 0;
        }