Re: [PATCH] sort: fix failure if sort's parent has ignored SIGCHLD

[Pádraig Brady]

Pádraig Brady wrote:
> The same issue as with the previous `timeout` patch.
> The attached includes at test, but I'll probably remove
> it because of the previously mentioned concerns.

really attached this time. sorry

>From 33904143eab537385ce1af58ea15c1876da402c7 Mon Sep 17 00:00:00 2001
From: =?utf-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Tue, 8 Dec 2009 08:48:34 +0000
Subject: [PATCH] sort: fix failure if sort's parent has ignored SIGCHLD

* src/sort.c (main): Reset the SIGCHLD handler to the default
as otherwise wait() could return an error.
* tests/misc/sort-compress: Set the CHLD handler to SIG_IGN to ensure
the sort command resets it to SIG_DFL.
* NEWS: Mention the fix.
---
 NEWS                     |    4 ++++
 src/sort.c               |    1 +
 tests/misc/sort-compress |    2 ++
 3 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/NEWS b/NEWS
index 19cca5b..528eedc 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,10 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   the presence of the empty string argument.
   [bug introduced in coreutils-8.0]
 
+  sort is now immune to the signal handling of its parent.
+  Specifically sort now doesn't exit with an error message
+  if it uses helper processes for compression and its parent
+  ignores CHLD signals. [bug introduced in coreutils-6.9]
 
 * Noteworthy changes in release 8.1 (2009-11-18) [stable]
 
diff --git a/src/sort.c b/src/sort.c
index 8709e53..70e0bbb 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -3254,6 +3254,7 @@ main (int argc, char **argv)
         }
 #endif
   }
+  signal (SIGCHLD, SIG_DFL); /* Don't inherit CHLD handling from parent.  */
 
   /* The signal mask is known, so it is safe to invoke exit_cleanup.  */
   atexit (exit_cleanup);
diff --git a/tests/misc/sort-compress b/tests/misc/sort-compress
index 7e4278e..e923e64 100755
--- a/tests/misc/sort-compress
+++ b/tests/misc/sort-compress
@@ -23,6 +23,8 @@ fi
 
 . $srcdir/test-lib.sh
 
+trap '' CHLD # ensure `sort` is immune to parent's SIGCHLD handler
+
 seq -w 2000 > exp || framework_failure
 tac exp > in || framework_failure
 SORT="$abs_top_builddir/src/sort"
-- 
1.6.2.5