implement udev_device_new_from_subsystem_sysname

README.md

@@ -8,7 +8,7 @@ What Works
 * [x] xorg-server
 * [x] libinput
 * [ ] wlroots - partially works. someone reported that mouse doesn't work
-* [ ] weston - need implement udev_device_new_from_subsystem_sysname()
+* [ ] weston - should work. need test
 * [ ] kwin - fails to compile for odd reason
 * [ ] ???
 

udev_device.c

@@ -514,7 +514,22 @@ UDEV_EXPORT struct udev_device *udev_device_new_from_devnum(struct udev *udev, c
 
 UDEV_EXPORT struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 {
-    // XXX NOT IMPLEMENTED
+    char *fmt[] = { "/sys/bus/%s/devices/%s", "/sys/class/%s/%s", NULL };
+    char path[PATH_MAX];
+    int i;
+
+    if (!udev || !subsystem || !sysname) {
+        return NULL;
+    }
+
+    for (i = 0; fmt[i]; i++) {
+        snprintf(path, sizeof(path), fmt[i], subsystem, sysname);
+
+        if (access(path, R_OK)) {
+            return udev_device_new_from_syspath(udev, path);
+        }
+    }
+
     return NULL;
 }