/*
- * 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
*
* 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.
*
*/
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;
dbg("add to cache '%s'", path_full);
list_add(&attr->node, &attr_list);
- /* read attribute value */
- fd = open(path_full, O_RDONLY);
- if (fd < 0) {
- dbg("attribute '%s' does not exist", path_full);
+ if (lstat(path_full, &statbuf) != 0) {
+ dbg("stat '%s' failed: %s", path_full, strerror(errno));
goto out;
}
- size = read(fd, value, sizeof(value));
- close(fd);
- if (size < 0)
- goto out;
- if (size == sizeof(value))
- goto out;
- /* 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);
- strlcpy(attr->value_local, value, sizeof(attr->value_local));
- attr->value = attr->value_local;
+ 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;
+ }
+ }
+ } else {
+ /* read attribute value */
+ fd = open(path_full, O_RDONLY);
+ if (fd < 0) {
+ dbg("attribute '%s' does not exist", path_full);
+ goto out;
+ }
+ size = read(fd, value, sizeof(value));
+ close(fd);
+ if (size < 0)
+ goto out;
+ if (size == sizeof(value))
+ goto out;
+
+ /* got a valid value, store and return it */
+ value[size] = '\0';
+ remove_trailing_chars(value, '\n');
+ dbg("cache '%s' with attribute value '%s'", path_full, value);
+ strlcpy(attr->value_local, value, sizeof(attr->value_local));
+ attr->value = attr->value_local;
+ }
out:
return attr->value;