libudev: udev_device - read "driver" value

4 files changed, 24 insertions, 2 deletions

diff --git a/udev/lib/libudev-device.c b/udev/lib/libudev-device.c
index 00b9440386..578afe7ec2 100644
--- a/udev/lib/libudev-device.c
+++ b/udev/lib/libudev-device.c
@@ -346,8 +346,15 @@ int udev_device_get_properties(struct udev_device *udev_device,
 
 const char *udev_device_get_driver(struct udev_device *udev_device)
 {
+	char driver[NAME_SIZE];
+
 	if (udev_device == NULL)
 		return NULL;
+	if (udev_device->driver != NULL)
+		return udev_device->driver;
+	if (util_get_sys_driver(udev_device->udev, udev_device->devpath, driver, sizeof(driver)) < 2)
+		return NULL;
+	udev_device->driver = strdup(driver);
 	return udev_device->driver;
 }
 
diff --git a/udev/lib/libudev-private.h b/udev/lib/libudev-private.h
index 53a58cc619..bc91927bed 100644
--- a/udev/lib/libudev-private.h
+++ b/udev/lib/libudev-private.h
@@ -99,4 +99,5 @@ extern int udev_ctrl_get_set_max_childs(struct udev_ctrl_msg *ctrl_msg);
 
 /* libudev-utils */
 extern ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size);
+extern ssize_t util_get_sys_driver(struct udev *udev, const char *devpath, char *driver, size_t size);
 #endif
diff --git a/udev/lib/libudev-utils.c b/udev/lib/libudev-utils.c
index 8251b64da9..82acb1a481 100644
--- a/udev/lib/libudev-utils.c
+++ b/udev/lib/libudev-utils.c
@@ -32,7 +32,7 @@
 #include "libudev-private.h"
 #include "../udev.h"
 
-ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size)
+static ssize_t get_sys_link(struct udev *udev, const char *slink, const char *devpath, char *subsystem, size_t size)
 {
 	char path[PATH_SIZE];
 	ssize_t len;
@@ -40,7 +40,8 @@ ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *sub
 
 	strlcpy(path, udev_get_sys_path(udev), sizeof(path));
 	strlcat(path, devpath, sizeof(path));
-	strlcat(path, "/subsystem", sizeof(path));
+	strlcat(path, "/", sizeof(path));
+	strlcat(path, slink, sizeof(path));
 	len = readlink(path, path, sizeof(path));
 	if (len < 0 || len >= (ssize_t) sizeof(path))
 		return -1;
@@ -51,3 +52,14 @@ ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *sub
 	pos = &pos[1];
 	return strlcpy(subsystem, pos, size);
 }
+
+ssize_t util_get_sys_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size)
+{
+	return get_sys_link(udev, "subsystem", devpath, subsystem, size);
+}
+
+ssize_t util_get_sys_driver(struct udev *udev, const char *devpath, char *driver, size_t size)
+{
+	return get_sys_link(udev, "driver", devpath, driver, size);
+}
+
diff --git a/udev/lib/test-libudev.c b/udev/lib/test-libudev.c
index 835536af84..4fdef68881 100644
--- a/udev/lib/test-libudev.c
+++ b/udev/lib/test-libudev.c
@@ -58,6 +58,8 @@ static void print_device(struct udev_device *device)
 	printf("devpath:   '%s'\n", str);
 	str = udev_device_get_subsystem(device);
 	printf("subsystem: '%s'\n", str);
+	str = udev_device_get_driver(device);
+	printf("driver:    '%s'\n", str);
 	str = udev_device_get_syspath(device);
 	printf("syspath:   '%s'\n", str);
 	str = udev_device_get_devname(device);