Re: [PATCH v6 00/16] daemon-win32

On Wed, Nov 3, 2010 at 11:18 PM, Erik Faye-Lund [off-list ref] wrote:

On Wed, Nov 3, 2010 at 10:11 PM, Pat Thoyts
[off-list ref] wrote:

quoted

Erik Faye-Lund [off-list ref] writes:

quoted

Here's hopefully the last iteration of this series. The previous version
only got a single complain about a typo in the subject of patch 14/15, so
it seems like most controversies have been settled.

I pulled this win32-daemon branch into my msysgit build tree and built
it. I get the following warnings:

   CC daemon.o
daemon.c: In function 'service_loop':
daemon.c:674: warning: dereferencing pointer 'ss.124' does break strict-aliasing rules
daemon.c:676: warning: dereferencing pointer 'ss.124' does break strict-aliasing rules
daemon.c:681: warning: dereferencing pointer 'ss.124' does break strict-aliasing rules
daemon.c:919: note: initialized from here
daemon.c:679: warning: dereferencing pointer 'sin_addr' does break strict-aliasing rules
daemon.c:675: note: initialized from here
daemon.c:691: warning: dereferencing pointer 'sin6_addr' does break strict-aliasing rules
daemon.c:682: note: initialized from here

Yeah, I'm aware of these. I thought those warnings were already
present in the Linux build, but checking again I see that that's not
the case. Need to investigate.

OK, it's the patch "daemon: use run-command api for async serving"
that introduce the warning. But looking closer at the patch it doesn't
seem the patch actually introduce the strict-aliasing violation, it's
there already. The patch only seems to change the code enough for GCC
to start realize there's a problem. Unless I'm misunderstanding
something vital, that is.

Anyway, here's a patch that makes it go away, I guess I'll squash it
into the next round.

diff --git a/daemon.c b/daemon.c
index 6eee570..d636446 100644
--- a/daemon.c
+++ b/daemon.c

@@ -1159,14 +1159,13 @@ int main(int argc, char **argv)
 	}

 	if (inetd_mode || serve_mode) {
-		struct sockaddr_storage ss;
-		struct sockaddr *peer = (struct sockaddr *)&ss;
-		socklen_t slen = sizeof(ss);
+		struct sockaddr sa;
+		socklen_t slen = sizeof(sa);

-		if (getpeername(0, peer, &slen))
-			peer = NULL;
-
-		return execute(peer);
+		if (getpeername(0, &sa, &slen))
+			return execute(NULL);
+		else
+			return execute(&sa);
 	}

 	if (detach) {