Subject: Re: bug#34134: 27.0.50; process-contact for accepted sockets broken
From: Paul Eggert <[email-masked]>
To: Eli Zaretskii <[email-masked]>, Mathew Handugan <[email-masked]>
Cc: [email-masked]
Date: Wed, 30 Jan 2019 15:13:51 -0800
List-Id: <debbugs-submit.debbugs.gnu.org>

On 1/25/19 12:07 AM, Eli Zaretskii wrote:
>> From: Mathew Handugan <[email-masked]>
>> Date: Fri, 18 Jan 2019 22:52:41 -0800
>>
>> Git commit be9e60fc3c43cc49cc5d749924c3e96737ae297c  causes accepted sockets to store 't as :host
>> instead of the string-formatted peer IP address.
>>
>> This manifests as
>>   (process-contact proc)
>> returning something like
>>   (t 55269)
>>
>> instead of the expected:
>>   ("192.168.2.13" 55269)
> Thanks.  Paul, could you please take a look at this?

Thanks for reporting the bug, especially the test case. I reproduce the 
problem and fixed it by installing the attached patch into the emacs-26 
branch on Savannah.

From 16d92c9748fe0eb75ec20a1117700525538b5bd0 Mon Sep 17 00:00:00 2001
From: Paul Eggert <[email-masked]>
Date: Wed, 30 Jan 2019 15:11:17 -0800
Subject: [PATCH] Fix process-contact bug with TCP connections

This fixes a regression from Emacs 25.3 (Bug#34134).
* src/process.c (server_accept_connection):
Set host correctly, fixing a bug introduced in
2017-09-16T21:29:[email-masked]
when working around a GCC bug.
---
 src/process.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/process.c b/src/process.c
index 7f32150e8e..d8acd139c0 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4724,19 +4724,24 @@ server_accept_connection (Lisp_Object server, int channel)
   service = Qnil;
   Lisp_Object args[11];
   int nargs = 0;
-  AUTO_STRING (procname_format_in, "%s <%d.%d.%d.%d:%d>");
-  AUTO_STRING (procname_format_in6, "%s <[%x:%x:%x:%x:%x:%x:%x:%x]:%d>");
+  #define HOST_FORMAT_IN "%d.%d.%d.%d"
+  #define HOST_FORMAT_IN6 "%x:%x:%x:%x:%x:%x:%x:%x"
+  AUTO_STRING (host_format_in, HOST_FORMAT_IN);
+  AUTO_STRING (host_format_in6, HOST_FORMAT_IN6);
+  AUTO_STRING (procname_format_in, "%s <"HOST_FORMAT_IN":%d>");
+  AUTO_STRING (procname_format_in6, "%s <["HOST_FORMAT_IN6"]:%d>");
   AUTO_STRING (procname_format_default, "%s <%d>");
   switch (saddr.sa.sa_family)
     {
     case AF_INET:
       {
 	args[nargs++] = procname_format_in;
-	nargs++;
+	args[nargs++] = host_format_in;
 	unsigned char *ip = (unsigned char *)&saddr.in.sin_addr.s_addr;
 	service = make_number (ntohs (saddr.in.sin_port));
 	for (int i = 0; i < 4; i++)
 	  args[nargs++] = make_number (ip[i]);
+	host = Fformat (5, args + 1);
 	args[nargs++] = service;
       }
       break;
@@ -4745,11 +4750,12 @@ server_accept_connection (Lisp_Object server, int channel)
     case AF_INET6:
       {
 	args[nargs++] = procname_format_in6;
-	nargs++;
+	args[nargs++] = host_format_in6;
 	DECLARE_POINTER_ALIAS (ip6, uint16_t, &saddr.in6.sin6_addr);
 	service = make_number (ntohs (saddr.in.sin_port));
 	for (int i = 0; i < 8; i++)
 	  args[nargs++] = make_number (ip6[i]);
+	host = Fformat (9, args + 1);
 	args[nargs++] = service;
       }
       break;
-- 
2.20.1