passt: Don't fork into background until the UNIX domain socket isn't listening

Once passt forks to background, it should be guaranteed that the UNIX
domain socket is available, otherwise, if qemu is started right after
it, it might fail to connect.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/passt.c b/passt.c
index 1fa9ce2..228a886 100644
--- a/passt.c
+++ b/passt.c
@@ -757,10 +757,6 @@ int main(int argc, char **argv)
 	openlog("passt", LOG_PERROR, LOG_DAEMON);
 #else
 	openlog("passt", 0, LOG_DAEMON);
-	if (daemon(0, 0)) {
-		fprintf(stderr, "Failed to fork into background\n");
-		exit(EXIT_FAILURE);
-	}
 #endif
 
 	get_routes(&c);
@@ -812,6 +808,13 @@ listen:
 	info("    kvm ... -net socket,connect="
 	     UNIX_SOCK_PATH " -net nic,model=virtio");
 
+#ifndef DEBUG
+	if (daemon(0, 0)) {
+		fprintf(stderr, "Failed to fork into background\n");
+		exit(EXIT_FAILURE);
+	}
+#endif
+
 	c.fd_unix = accept(fd_unix, NULL, NULL);
 	ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP;
 	ev.data.fd = c.fd_unix;