libudev: get rid of udev_sysfs.c

[elogind.git] / udev / lib / libudev-utils.c

diff --git a/udev/lib/libudev-utils.c b/udev/lib/libudev-utils.c
index 82acb1a4815705d5a36ee01cb1470d89e20a5e9c..e5f1ed7c38d66af5a95b624a217e282553260f15 100644 (file)
--- a/udev/lib/libudev-utils.c
+++ b/udev/lib/libudev-utils.c
@@ -63,3 +63,34 @@ ssize_t util_get_sys_driver(struct udev *udev, const char *devpath, char *driver
        return get_sys_link(udev, "driver", devpath, driver, size);
 }
 
+int util_resolve_sys_link(struct udev *udev, char *devpath, size_t size)
+{
+       char link_path[PATH_SIZE];
+       char link_target[PATH_SIZE];
+       int len;
+       int i;
+       int back;
+
+       strlcpy(link_path, udev_get_sys_path(udev), 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(udev, "path link '%s' points to '%s'\n", devpath, link_target);
+
+       for (back = 0; strncmp(&link_target[back * 3], "../", 3) == 0; back++)
+               ;
+       dbg(udev, "base '%s', tail '%s', back %i\n", 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(udev, "after moving back '%s'\n", devpath);
+       strlcat(devpath, "/", size);
+       strlcat(devpath, &link_target[back * 3], size);
+       return 0;
+}