X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev_sysfs.c;h=0e448894fef8f3c6edee1a0cd49cdd631f4d2893;hp=ddc0b46790066e30bede2c9bb0026a271633795c;hb=82c60ce57206148d00e8d3a210a72a0e7f2aa380;hpb=7e75cfa6fe0818ffb76c2a5a88c8572f04bda879

diff --git a/udev_sysfs.c b/udev_sysfs.c
index ddc0b4679..0e448894f 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.
  *
  */
 
@@ -79,24 +77,27 @@ void sysfs_cleanup(void)
 	}
 }
 
-void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath, const char *subsystem)
+void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
+			     const char *subsystem, const char *driver)
 {
 	char *pos;
 
 	strlcpy(dev->devpath, devpath, sizeof(dev->devpath));
 	if (subsystem != NULL)
 		strlcpy(dev->subsystem, subsystem, sizeof(dev->subsystem));
+	if (driver != NULL)
+		strlcpy(dev->driver, driver, sizeof(dev->driver));
 
 	/* set kernel name */
 	pos = strrchr(dev->devpath, '/');
 	if (pos == NULL)
 		return;
 
-	strlcpy(dev->kernel_name, &pos[1], sizeof(dev->kernel_name));
-	dbg("kernel_name='%s'", dev->kernel_name);
+	strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel));
+	dbg("kernel='%s'", dev->kernel);
 
 	/* some devices have '!' in their name, change that to '/' */
-	pos = dev->kernel_name;
+	pos = dev->kernel;
 	while (pos[0] != '\0') {
 		if (pos[0] == '!')
 			pos[0] = '/';
@@ -104,13 +105,45 @@ void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath, cons
 	}
 
 	/* get kernel number */
-	pos = &dev->kernel_name[strlen(dev->kernel_name)];
+	pos = &dev->kernel[strlen(dev->kernel)];
 	while (isdigit(pos[-1]))
 		pos--;
 	strlcpy(dev->kernel_number, pos, sizeof(dev->kernel_number));
 	dbg("kernel_number='%s'", dev->kernel_number);
 }
 
+int sysfs_resolve_link(char *devpath, size_t size)
+{
+	char link_path[PATH_SIZE];
+	char link_target[PATH_SIZE];
+	int len;
+	int i;
+	int back;
+
+	strlcpy(link_path, sysfs_path, sizeof(link_path));
+	strlcat(link_path, devpath, sizeof(link_path));
+	len = readlink(link_path, link_target, sizeof(link_target));
+	if (len <= 0)
+		return -1;
+	link_target[len] = '\0';
+	dbg("path link '%s' points to '%s'", devpath, link_target);
+
+	for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
+		;
+	dbg("base '%s', tail '%s', back %i", devpath, &link_target[back * 3], back);
+	for (i = 0; i <= back; i++) {
+		char *pos = strrchr(devpath, '/');
+
+		if (pos == NULL)
+			return -1;
+		pos[0] = '\0';
+	}
+	dbg("after moving back '%s'", devpath);
+	strlcat(devpath, "/", size);
+	strlcat(devpath, &link_target[back * 3], size);
+	return 0;
+}
+
 struct sysfs_device *sysfs_device_get(const char *devpath)
 {
 	char path[PATH_SIZE];
@@ -143,27 +176,8 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 		return NULL;
 	}
 	if (S_ISLNK(statbuf.st_mode)) {
-		int i;
-		int back;
-
-		len = readlink(path, link_target, sizeof(link_target));
-		if (len <= 0)
+		if (sysfs_resolve_link(devpath_real, sizeof(devpath_real)) != 0)
 			return NULL;
-		link_target[len] = '\0';
-		dbg("devpath link '%s' points to '%s'", path, link_target);
-
-		for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
-			;
-		dbg("base '%s', tail '%s', back %i", devpath_real, &link_target[back * 3], back);
-		for (i = 0; i <= back; i++) {
-			pos = strrchr(devpath_real, '/');
-			if (pos == NULL)
-				return NULL;
-			pos[0] = '\0';
-		}
-		dbg("after moving back '%s'", devpath_real);
-		strlcat(devpath_real, "/", sizeof(devpath_real));
-		strlcat(devpath_real, &link_target[back * 3], sizeof(devpath_real));
 
 		/* now look for device in cache after path translation */
 		list_for_each_entry(dev_loop, &dev_list, node) {
@@ -181,7 +195,7 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 		return NULL;
 	memset(dev, 0x00, sizeof(struct sysfs_device));
 
-	sysfs_device_set_values(dev, devpath_real, NULL);
+	sysfs_device_set_values(dev, devpath_real, NULL, NULL);
 
 	/* get subsystem */
 	if (strncmp(dev->devpath, "/class/", 7) == 0) {
@@ -246,12 +260,7 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 {
 	char parent_devpath[PATH_SIZE];
-	char device_link[PATH_SIZE];
-	char device_link_target[PATH_SIZE];
 	char *pos;
-	int i;
-	int len;
-	int back;
 
 	dbg("open '%s'", dev->devpath);
 
@@ -297,28 +306,10 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 	return dev->parent;
 
 device_link:
-	strlcpy(device_link, sysfs_path, sizeof(device_link));
-	strlcat(device_link, dev->devpath, sizeof(device_link));
-	strlcat(device_link, "/device", sizeof(device_link));
-	len = readlink(device_link, device_link_target, sizeof(device_link_target));
-	if (len < 0)
-		return NULL;
-	device_link_target[len] = '\0';
-	dbg("device link '%s' points to '%s'", device_link, device_link_target);
-
-	for (back = 0; strncmp(&device_link_target[back * 3], "../", 3) == 0; back++)
-		;
 	strlcpy(parent_devpath, dev->devpath, sizeof(parent_devpath));
-	dbg("base='%s', tail='%s', back=%i", parent_devpath, &device_link_target[back * 3], back);
-	for (i = 0; i < back; i++) {
-		pos = strrchr(parent_devpath, '/');
-		if (pos == NULL)
-			return NULL;
-		pos[0] = '\0';
-	}
-	dbg("after moving back '%s'", parent_devpath);
-	strlcat(parent_devpath, "/", sizeof(parent_devpath));
-	strlcat(parent_devpath, &device_link_target[back * 3], sizeof(parent_devpath));
+	strlcat(parent_devpath, "/device", sizeof(parent_devpath));
+	if (sysfs_resolve_link(parent_devpath, sizeof(parent_devpath)) != 0)
+		return NULL;
 
 	/* get parent and remember it */
 	dev->parent = sysfs_device_get(parent_devpath);
@@ -345,6 +336,7 @@ 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;
@@ -374,6 +366,38 @@ 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) {
@@ -390,7 +414,7 @@ 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;