1 files changed, 55 insertions, 36 deletions

diff --git a/libudev/libudev-monitor.c b/libudev/libudev-monitor.c
index c97f6faa65..5d9e155722 100644
--- a/libudev/libudev-monitor.c
+++ b/libudev/libudev-monitor.c
@@ -50,6 +50,7 @@ struct udev_monitor {
 	socklen_t addrlen;
 	struct udev_list_node filter_subsystem_list;
 	struct udev_list_node filter_tag_list;
+	bool bound;
 };
 
 enum udev_monitor_netlink_group {
@@ -155,32 +156,7 @@ struct udev_monitor *udev_monitor_new_from_socket(struct udev *udev, const char
 	return udev_monitor;
 }
 
-/**
- * udev_monitor_new_from_netlink:
- * @udev: udev library context
- * @name: name of event source
- *
- * Create new udev monitor and connect to a specified event
- * source. Valid sources identifiers are "udev" and "kernel".
- *
- * Applications should usually not connect directly to the
- * "kernel" events, because the devices might not be useable
- * at that time, before udev has configured them, and created
- * device nodes.
- *
- * Accessing devices at the same time as udev, might result
- * in unpredictable behavior.
- *
- * The "udev" events are sent out after udev has finished its
- * event processing, all rules have been processed, and needed
- * device nodes are created.
- *
- * The initial refcount is 1, and needs to be decremented to
- * release the resources of the udev monitor.
- *
- * Returns: a new udev monitor, or #NULL, in case of an error
- **/
-struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name)
+struct udev_monitor *udev_monitor_new_from_netlink_fd(struct udev *udev, const char *name, int fd)
 {
 	struct udev_monitor *udev_monitor;
 	unsigned int group;
@@ -201,11 +177,16 @@ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char
 	if (udev_monitor == NULL)
 		return NULL;
 
-	udev_monitor->sock = socket(PF_NETLINK, SOCK_DGRAM|SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);
-	if (udev_monitor->sock == -1) {
-		err(udev, "error getting socket: %m\n");
-		free(udev_monitor);
-		return NULL;
+	if (fd < 0) {
+		udev_monitor->sock = socket(PF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_KOBJECT_UEVENT);
+		if (udev_monitor->sock == -1) {
+			err(udev, "error getting socket: %m\n");
+			free(udev_monitor);
+			return NULL;
+		}
+	} else {
+		udev_monitor->bound = true;
+		udev_monitor->sock = fd;
 	}
 
 	udev_monitor->snl.nl_family = AF_NETLINK;
@@ -219,6 +200,36 @@ struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char
 	return udev_monitor;
 }
 
+/**
+ * udev_monitor_new_from_netlink:
+ * @udev: udev library context
+ * @name: name of event source
+ *
+ * Create new udev monitor and connect to a specified event
+ * source. Valid sources identifiers are "udev" and "kernel".
+ *
+ * Applications should usually not connect directly to the
+ * "kernel" events, because the devices might not be useable
+ * at that time, before udev has configured them, and created
+ * device nodes.
+ *
+ * Accessing devices at the same time as udev, might result
+ * in unpredictable behavior.
+ *
+ * The "udev" events are sent out after udev has finished its
+ * event processing, all rules have been processed, and needed
+ * device nodes are created.
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev monitor.
+ *
+ * Returns: a new udev monitor, or #NULL, in case of an error
+ **/
+struct udev_monitor *udev_monitor_new_from_netlink(struct udev *udev, const char *name)
+{
+	return udev_monitor_new_from_netlink_fd(udev, name, -1);
+}
+
 static inline void bpf_stmt(struct sock_filter *inss, unsigned int *i,
 			    unsigned short code, unsigned int data)
 {
@@ -364,16 +375,24 @@ int udev_monitor_allow_unicast_sender(struct udev_monitor *udev_monitor, struct
  */
 int udev_monitor_enable_receiving(struct udev_monitor *udev_monitor)
 {
-	int err;
+	int err = 0;
 	const int on = 1;
 
 	if (udev_monitor->sun.sun_family != 0) {
-		err = bind(udev_monitor->sock,
-			   (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
+		if (!udev_monitor->bound) {
+			err = bind(udev_monitor->sock,
+				   (struct sockaddr *)&udev_monitor->sun, udev_monitor->addrlen);
+			if (err == 0)
+				udev_monitor->bound = true;
+		}
 	} else if (udev_monitor->snl.nl_family != 0) {
 		udev_monitor_filter_update(udev_monitor);
-		err = bind(udev_monitor->sock,
-			   (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
+		if (!udev_monitor->bound) {
+			err = bind(udev_monitor->sock,
+				   (struct sockaddr *)&udev_monitor->snl, sizeof(struct sockaddr_nl));
+			if (err == 0)
+				udev_monitor->bound = true;
+		}
 		if (err == 0) {
 			struct sockaddr_nl snl;
 			socklen_t addrlen;