X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev_sysfs.c;h=0b7561f0eba7beb3db5e484cd9376b83e3320f05;hp=c4afe0cffba90a95f88ecf4feef4928e3073f765;hb=4a51530993e28c9a689be535fd1d34b259b39f2a;hpb=95776dc6ec174f47fa4dd4d8abf5d457223e5dd4

diff --git a/udev_sysfs.c b/udev_sysfs.c
index c4afe0cff..0b7561f0e 100644
--- 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;