passt, tap: Daemonise once socket is ready without waiting for connection

The existing behaviour is not really practical: an automated agent in
charge of starting both qemu and passt would need to fork itself to
start passt, because passt won't fork to background until qemu
connects, and the agent needs to unblock to start qemu.

Instead of waiting for a connection to daemonise, do it right away as
soon as a socket is available: that can be considered an initialised
state already.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/passt.c b/passt.c
index 3c9fb90..a8bb88e 100644
--- a/passt.c
+++ b/passt.c
@@ -345,6 +345,7 @@ int main(int argc, char **argv)
 	}
 	sock_probe_mem(&c);
 
+	c.fd_tap = c.fd_tap_listen = -1;
 	tap_sock_init(&c);
 
 	clock_gettime(CLOCK_MONOTONIC, &now);
@@ -387,9 +388,10 @@ loop:
 
 	for (i = 0; i < nfds; i++) {
 		union epoll_ref ref = *((union epoll_ref *)&events[i].data.u64);
+		int fd = events[i].data.fd;
 
-		if (events[i].data.fd == c.fd_tap)
-			tap_handler(&c, events[i].events, &now);
+		if (fd == c.fd_tap || fd == c.fd_tap_listen)
+			tap_handler(&c, fd, events[i].events, &now);
 		else
 			sock_handler(&c, ref, events[i].events, &now);
 	}