release 099

[elogind.git] / udev_sysfs.c

diff --git a/udev_sysfs.c b/udev_sysfs.c
index c4afe0cffba90a95f88ecf4feef4928e3073f765..0b7561f0eba7beb3db5e484cd9376b83e3320f05 100644 (file)
--- a/udev_sysfs.c
+++ b/udev_sysfs.c
@@ -1,7 +1,5 @@
 /*
- * udev_sysfs.c - sysfs access
- *
- * Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2005-2006 Kay Sievers <kay.sievers@vrfy.org>
  *
  *     This program is free software; you can redistribute it and/or modify it
  *     under the terms of the GNU General Public License as published by the
@@ -14,7 +12,7 @@
  * 
  *     You should have received a copy of the GNU General Public License along
  *     with this program; if not, write to the Free Software Foundation, Inc.,
- *     675 Mass Ave, Cambridge, MA 02139, USA.
+ *     51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  *
  */
 
@@ -348,6 +346,7 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
        char value[NAME_SIZE];
        struct sysfs_attr *attr_loop;
        struct sysfs_attr *attr;
+       struct stat statbuf;
        int fd;
        ssize_t size;
        size_t sysfs_len;
@@ -377,6 +376,38 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
        dbg("add to cache '%s'", path_full);
        list_add(&attr->node, &attr_list);
 
+       if (lstat(path_full, &statbuf) != 0) {
+               dbg("stat '%s' failed: %s", path_full, strerror(errno));
+               goto out;
+       }
+
+       if (S_ISLNK(statbuf.st_mode)) {
+               /* links return the last element of the target path */
+               char link_target[PATH_SIZE];
+               int len;
+               const char *pos;
+
+               len = readlink(path_full, link_target, sizeof(link_target));
+               if (len > 0) {
+                       link_target[len] = '\0';
+                       pos = strrchr(link_target, '/');
+                       if (pos != NULL) {
+                               dbg("cache '%s' with link value '%s'", path_full, value);
+                               strlcpy(attr->value_local, &pos[1], sizeof(attr->value_local));
+                               attr->value = attr->value_local;
+                       }
+               }
+               goto out;
+       }
+
+       /* skip directories */
+       if (S_ISDIR(statbuf.st_mode))
+               goto out;
+
+       /* skip non-readable files */
+       if ((statbuf.st_mode & S_IRUSR) == 0)
+               goto out;
+
        /* read attribute value */
        fd = open(path_full, O_RDONLY);
        if (fd < 0) {
@@ -393,7 +424,7 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
        /* got a valid value, store and return it */
        value[size] = '\0';
        remove_trailing_chars(value, '\n');
-       dbg("cache '%s' with value '%s'", path_full, value);
+       dbg("cache '%s' with attribute value '%s'", path_full, value);
        strlcpy(attr->value_local, value, sizeof(attr->value_local));
        attr->value = attr->value_local;