1 files changed, 53 insertions, 0 deletions
diff --git a/udev/lib/libudev-utils.c b/udev/lib/libudev-utils.c
new file mode 100644
index 0000000000..8251b64da9
--- /dev/null
+++ b/udev/lib/libudev-utils.c
@@ -0,0 +1,53 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+#include "libudev.h"
+#include "libudev-private.h"
+#include "../udev.h"
+
+ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size)
+{
+	char path[PATH_SIZE];
+	ssize_t len;
+	const char *pos;
+
+	strlcpy(path, udev_get_sys_path(udev), sizeof(path));
+	strlcat(path, devpath, sizeof(path));
+	strlcat(path, "/subsystem", sizeof(path));
+	len = readlink(path, path, sizeof(path));
+	if (len < 0 || len >= (ssize_t) sizeof(path))
+		return -1;
+	path[len] = '\0';
+	pos = strrchr(path, '/');
+	if (pos == NULL)
+		return -1;
+	pos = &pos[1];
+	return strlcpy(subsystem, pos, size);
+}