Re: [PATCH] resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]

[Florian Weimer <fweimer at redhat dot com>]

* Joseph Myers:

> This has broken the build for Hurd:
>
> res_enable_icmp.c: In function '__res_enable_icmp':
> res_enable_icmp.c:30:38: error: 'IP_RECVERR' undeclared (first use in this function); did you mean 'IPV6_RECVERR'?
>
> No idea why the generic bits/in.h as used for Hurd defines IPV6_RECVERR 
> but not IP_RECVERR, or what Hurd actually implements in this regard.

Sorry about that.

Thanks for pointing out the IPV6_RECVERR definition, I would have missed
that.

XNU does not support IP_RECVERR either, so I think the safest way to
deal with this is the attached patch.

Alternatively, I could add the stub to the generic code, but I think
doing it this way is clearer for those who read just the resolv code.

Thanks,
Florian

hurd: Add no-op version of __res_enable_icmp [BZ #24047]

Mach does not support IP_RECVERR, so replace this function with a
stub in a sysdeps override for Hurd.

This fixes commit 08504de71813ddbd447bfbca4a325cbe8ce8bcda
("resolv: Enable full ICMP errors for UDP DNS sockets [BZ #24047]").

2019-03-12  Florian Weimer  <fweimer@redhat.com>

	[BZ #24047]
	* sysdeps/mach/hurd/res_enable_icmp.c: New file.

diff --git a/sysdeps/mach/hurd/res_enable_icmp.c b/sysdeps/mach/hurd/res_enable_icmp.c
new file mode 100644
index 0000000000..4b0456340c
--- /dev/null
+++ b/sysdeps/mach/hurd/res_enable_icmp.c
@@ -0,0 +1,27 @@
+/* Enable full ICMP errors on a socket.  No-op version for Hurd.
+   Copyright (C) 2019 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Mach does not support the IP_RECVERR extension.  */
+
+#include <resolv.h>
+
+int
+__res_enable_icmp (int family, int fd)
+{
+  return 0;
+}