X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udev_sysfs.c;h=1846a42f6accd18be58a73297a81119b179713c3;hp=e733d417c5628854ee5f1d4f06b463873a1d0944;hb=9377c8d80c1530c7b006115daa0ccab4d40f4d93;hpb=eef5447934a07279bc76f3f65b0302ddea8556ab

diff --git a/udev_sysfs.c b/udev_sysfs.c
index e733d417c..1846a42f6 100644
--- a/udev_sysfs.c
+++ b/udev_sysfs.c
@@ -92,7 +92,6 @@ void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
 	pos = strrchr(dev->devpath, '/');
 	if (pos == NULL)
 		return;
-
 	strlcpy(dev->kernel, &pos[1], sizeof(dev->kernel));
 	dbg("kernel='%s'", dev->kernel);
 
@@ -112,6 +111,38 @@ void sysfs_device_set_values(struct sysfs_device *dev, const char *devpath,
 	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];
@@ -144,27 +175,8 @@ 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) {
@@ -184,8 +196,20 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 
 	sysfs_device_set_values(dev, devpath_real, NULL, NULL);
 
-	/* get subsystem */
-	if (strncmp(dev->devpath, "/class/", 7) == 0) {
+	/* get subsystem name */
+	strlcpy(link_path, sysfs_path, sizeof(link_path));
+	strlcat(link_path, dev->devpath, sizeof(link_path));
+	strlcat(link_path, "/subsystem", sizeof(link_path));
+	len = readlink(link_path, link_target, sizeof(link_target));
+	if (len > 0) {
+		/* get subsystem from "subsystem" link */
+		link_target[len] = '\0';
+		dbg("subsystem link '%s' points to '%s'", link_path, link_target);
+		pos = strrchr(link_target, '/');
+		if (pos != NULL)
+			strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
+	} else if (strncmp(dev->devpath, "/class/", 7) == 0) {
+		/* get subsystem from class dir */
 		strlcpy(dev->subsystem, &dev->devpath[7], sizeof(dev->subsystem));
 		pos = strchr(dev->subsystem, '/');
 		if (pos != NULL)
@@ -206,38 +230,26 @@ struct sysfs_device *sysfs_device_get(const char *devpath)
 			pos = strrchr(link_target, '/');
 			if (pos != NULL)
 				strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
-		} else {
-			/* get subsystem from "subsystem" link */
-			strlcpy(link_path, sysfs_path, sizeof(link_path));
-			strlcat(link_path, dev->devpath, sizeof(link_path));
-			strlcat(link_path, "/subsystem", sizeof(link_path));
-			len = readlink(link_path, link_target, sizeof(link_target));
-			if (len > 0) {
-				link_target[len] = '\0';
-				dbg("subsystem link '%s' points to '%s'", link_path, link_target);
-				pos = strrchr(link_target, '/');
-				if (pos != NULL)
-					strlcpy(dev->subsystem, &pos[1], sizeof(dev->subsystem));
-			}
-		}
-		/* get driver name */
-		strlcpy(link_path, sysfs_path, sizeof(link_path));
-		strlcat(link_path, dev->devpath, sizeof(link_path));
-		strlcat(link_path, "/driver", sizeof(link_path));
-		len = readlink(link_path, link_target, sizeof(link_target));
-		if (len > 0) {
-			link_target[len] = '\0';
-			dbg("driver link '%s' points to '%s'", link_path, link_target);
-			pos = strrchr(link_target, '/');
-			if (pos != NULL)
-				strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
 		}
-	} else if (strncmp(dev->devpath, "/bus/", 5) == 0 && strstr(dev->devpath, "/drivers/")) {
+	} else if (strstr(dev->devpath, "/drivers/") != NULL) {
 		strlcpy(dev->subsystem, "drivers", sizeof(dev->subsystem));
 	} else if (strncmp(dev->devpath, "/module/", 8) == 0) {
 		strlcpy(dev->subsystem, "module", sizeof(dev->subsystem));
 	}
 
+	/* get driver name */
+	strlcpy(link_path, sysfs_path, sizeof(link_path));
+	strlcat(link_path, dev->devpath, sizeof(link_path));
+	strlcat(link_path, "/driver", sizeof(link_path));
+	len = readlink(link_path, link_target, sizeof(link_target));
+	if (len > 0) {
+		link_target[len] = '\0';
+		dbg("driver link '%s' points to '%s'", link_path, link_target);
+		pos = strrchr(link_target, '/');
+		if (pos != NULL)
+			strlcpy(dev->driver, &pos[1], sizeof(dev->driver));
+	}
+
 	dbg("add to cache 'devpath=%s', subsystem='%s', driver='%s'", dev->devpath, dev->subsystem, dev->driver);
 	list_add(&dev->node, &dev_list);
 
@@ -247,12 +259,7 @@ 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);
 
@@ -262,6 +269,7 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 
 	/* requesting a parent is only valid for devices */
 	if ((strncmp(dev->devpath, "/devices/", 9) != 0) &&
+	    (strncmp(dev->devpath, "/subsystem/", 11) != 0) &&
 	    (strncmp(dev->devpath, "/class/", 7) != 0) &&
 	    (strncmp(dev->devpath, "/block/", 7) != 0))
 		return NULL;
@@ -281,10 +289,13 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 		return NULL;
 	}
 
-	/* at the top level of class/block we want to follow the "device" link */
-	if (strcmp(parent_devpath, "/block") == 0) {
-		dbg("/block top level, look for device link");
-		goto device_link;
+	/* at the subsystems top level we want to follow the old-style "device" link */
+	if (strncmp(parent_devpath, "/subsystem", 10) == 0) {
+		pos = strrchr(parent_devpath, '/');
+		if (pos == &parent_devpath[10] || pos == parent_devpath || strcmp(pos, "/devices") == 0) {
+			dbg("/subsystem top level, look for device link");
+			goto device_link;
+		}
 	}
 	if (strncmp(parent_devpath, "/class", 6) == 0) {
 		pos = strrchr(parent_devpath, '/');
@@ -293,33 +304,20 @@ struct sysfs_device *sysfs_device_get_parent(struct sysfs_device *dev)
 			goto device_link;
 		}
 	}
+	if (strcmp(parent_devpath, "/block") == 0) {
+		dbg("/block top level, look for device link");
+		goto device_link;
+	}
+
 	/* get parent and remember it */
 	dev->parent = sysfs_device_get(parent_devpath);
 	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);
@@ -397,28 +395,37 @@ char *sysfs_attr_get_value(const char *devpath, const char *attr_name)
 				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;
+		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) {
+		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;
 }