mod_notionflux: fchmod of socket always fails on FreeBSD

[jeffpc]

On FreeBSD, mod_notionflux fails on start (xmessage opens mentioning an invalid argument error) because of an invalid arg related to the listening socket. start_listening tries to fchmod the newly created socket but on FreeBSD this always fails. The manpage for fchmod says:

     [EINVAL]           The fd argument refers to a socket, not to a file.

The following (hacky) patch fixes the issue and mod_notionflux seems to start up fine.

diff --git a/mod_notionflux/mod_notionflux.c b/mod_notionflux/mod_notionflux.c
index 51949e07..e9176c7c 100644
--- a/mod_notionflux/mod_notionflux.c
+++ b/mod_notionflux/mod_notionflux.c
@@ -328,8 +328,10 @@ static bool start_listening()
     if(listenfd<0)
         goto errwarn;

+#ifndef __FreeBSD__
     if(fchmod(listenfd, S_IRUSR|S_IWUSR)<0)
         goto errwarn;
+#endif

     addr.sun_family=AF_UNIX;

[wilhelmy]

While this should be fine from a security standpoint since we're wrapping the socket into a secured temporary directory, it still feels suboptimal until now that it's coming back to me that FreeBSD doesn't support permissions on socket files no matter whether per chmod or fchmod.

[jeffpc]

This fchmod is weird - it happens right after socket() - so this fd is a completely new socket and isn't associated with a path yet and so it makes perfect sense that the fchmod would fail. Note that the chmod after we bind the socket (a few lines later) succeeds.