udev_sysfs: unify symlink resolving

[elogind.git] / udev_sysfs.c

diff --git a/udev_sysfs.c b/udev_sysfs.c
index 0b7561f0eba7beb3db5e484cd9376b83e3320f05..0e448894fef8f3c6edee1a0cd49cdd631f4d2893 100644 (file)
--- a/udev_sysfs.c
+++ b/udev_sysfs.c
@@ -112,6 +112,38 @@ 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 +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) {
@@ -247,12 +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);
 
@@ -298,28 +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);