[PATCH] add MANAGED_EVENT to the forked udev environment

This will prevent a loop, if udev sends events back into the
daemon.

udevd.c

@@ -291,7 +291,7 @@ static void handle_udevsend_msg(int sock)
 	/* copy environment buffer and reconstruct envp */
 	memcpy(msg->envbuf, usend_msg.envbuf, envbuf_size);
 	bufpos = 0;
-	for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-1); i++) {
+	for (i = 0; (bufpos < envbuf_size) && (i < HOTPLUG_NUM_ENVP-2); i++) {
 		int keylen;
 		char *key;
 
@@ -314,6 +314,7 @@ static void handle_udevsend_msg(int sock)
 		if (strncmp(key, "SEQNUM=", 7) == 0)
 			msg->seqnum = strtoull(&key[7], NULL, 10);
 	}
+	msg->envp[i++] = "MANAGED_EVENT=1";
 	msg->envp[i] = NULL;
 
 	/* if no seqnum is given, we move straight to exec queue */

udevd.h

@@ -36,7 +36,7 @@
 
 struct udevsend_msg {
 	char magic[20];
-	char envbuf[HOTPLUG_BUFFER_SIZE];
+	char envbuf[HOTPLUG_BUFFER_SIZE+256];
 };
 
 struct hotplug_msg {
@@ -47,6 +47,6 @@ struct hotplug_msg {
 	char *devpath;
 	char *subsystem;
 	unsigned long long seqnum;
-	char *envp[HOTPLUG_NUM_ENVP];
+	char *envp[HOTPLUG_NUM_ENVP+1];
 	char envbuf[];
 };

udevsend.c

@@ -132,6 +132,12 @@ int main(int argc, char *argv[], char *envp[])
 		goto exit;
 	}
 
+	/* prevent loops in the scripts we execute */
+	if (getenv("MANAGED_EVENT") != NULL) {
+		dbg("seems that the event source is not the kernel, just exit");
+		goto exit;
+	}
+
 	sock = socket(AF_LOCAL, SOCK_DGRAM, 0);
 	if (sock == -1) {
 		dbg("error getting socket");