1 files changed, 35 insertions, 15 deletions

diff --git a/lib/igt_debugfs.c b/lib/igt_debugfs.c
index 63183e57..1e8c8cc3 100644
--- a/lib/igt_debugfs.c
+++ b/lib/igt_debugfs.c
@@ -127,38 +127,38 @@ const char *igt_debugfs_mount(void)
 }
 
 /**
- * igt_debugfs_dir:
+ * igt_debugfs_path:
  * @device: fd of the device
+ * @path: buffer to store path
+ * @pathlen: len of @path buffer.
  *
- * This opens the debugfs directory corresponding to device for use
- * with igt_sysfs_get() and related functions.
+ * This finds the debugfs directory corresponding to @device.
  *
  * Returns:
- * The directory fd, or -1 on failure.
+ * The directory path, or NULL on failure.
  */
-int igt_debugfs_dir(int device)
+char *igt_debugfs_path(int device, char *path, int pathlen)
 {
 	struct stat st;
 	const char *debugfs_root;
-	char path[200];
 	int idx;
 
 	if (fstat(device, &st)) {
 		igt_debug("Couldn't stat FD for DRM device: %s\n", strerror(errno));
-		return -1;
+		return NULL;
 	}
 
 	if (!S_ISCHR(st.st_mode)) {
 		igt_debug("FD for DRM device not a char device!\n");
-		return -1;
+		return NULL;
 	}
 
 	debugfs_root = igt_debugfs_mount();
 
 	idx = minor(st.st_rdev);
-	snprintf(path, sizeof(path), "%s/dri/%d/name", debugfs_root, idx);
+	snprintf(path, pathlen, "%s/dri/%d/name", debugfs_root, idx);
 	if (stat(path, &st))
-		return -1;
+		return NULL;
 
 	if (idx >= 64) {
 		int file, name_len, cmp_len;
@@ -166,17 +166,17 @@ int igt_debugfs_dir(int device)
 
 		file = open(path, O_RDONLY);
 		if (file < 0)
-			return -1;
+			return NULL;
 
 		name_len = read(file, name, sizeof(name));
 		close(file);
 
 		for (idx = 0; idx < 16; idx++) {
-			snprintf(path, sizeof(path), "%s/dri/%d/name",
+			snprintf(path, pathlen, "%s/dri/%d/name",
 				 debugfs_root, idx);
 			file = open(path, O_RDONLY);
 			if (file < 0)
-				return -1;
+				return NULL;
 
 			cmp_len = read(file, cmp, sizeof(cmp));
 			close(file);
@@ -186,10 +186,30 @@ int igt_debugfs_dir(int device)
 		}
 
 		if (idx == 16)
-			return -1;
+			return NULL;
 	}
 
-	snprintf(path, sizeof(path), "%s/dri/%d", debugfs_root, idx);
+	snprintf(path, pathlen, "%s/dri/%d", debugfs_root, idx);
+	return path;
+}
+
+/**
+ * igt_debugfs_dir:
+ * @device: fd of the device
+ *
+ * This opens the debugfs directory corresponding to device for use
+ * with igt_sysfs_get() and related functions.
+ *
+ * Returns:
+ * The directory fd, or -1 on failure.
+ */
+int igt_debugfs_dir(int device)
+{
+	char path[200];
+
+	if (!igt_debugfs_path(device, path, sizeof(path)))
+		return -1;
+
 	igt_debug("Opening debugfs directory '%s'\n", path);
 	return open(path, O_RDONLY);
 }