Fix kqueue usage when forking in the background

Summary:
NetBSD's kqueue(2) man page says "The queue is not inherited by a
child created with fork(2)", which means the poll_fd needs to be
reopen after forking in the background.

This is done by calling eloop_requeue() after daemon().

Fixes T127.

Tags: #parpd

Maniphest Tasks: T127

Differential Revision: https://dev.marples.name/D123

1 files changed, 11 insertions, 3 deletions

diff --git a/parpd.c b/parpd.c
index a178696..dbf26c4 100644
--- a/parpd.c
+++ b/parpd.c
@@ -718,9 +718,17 @@ main(int argc, char **argv)
 		goto out;
 	}
 
-	if (!fflag && daemon(0, 0) == -1) {
-		syslog(LOG_ERR, "daemon: %m");
-		goto out;
+	if (!fflag) {
+		if (daemon(0, 0) == -1) {
+			syslog(LOG_ERR, "daemon: %m");
+			goto out;
+		}
+
+		/* At least for kqueue, poll_fd gets invalidated by fork */
+                if (eloop_requeue(eloop) == -1) {
+                        syslog(LOG_ERR, "eloop_requeue after fork: %m");
+                        goto out;
+                }
 	}
 
 	opt = eloop_start(eloop, &sigset);