From a59f8174918000d12907cc27e51326e06a686c80 Mon Sep 17 00:00:00 2001
From: Bryan Drewery <bdrewery@FreeBSD.org>
Date: Sat, 18 Apr 2015 23:49:57 +0000
Subject: [PATCH] sh: Fix the trap builtin to be POSIX-compliant for 'trap exit
 SIG' and 'trap n n...'.

The parser considered 'trap exit INT' to reset the default for both EXIT and
INT. This beahvior is not POSIX compliant. This was avoided if a value was
specified for 'exit', but then disallows exiting with the signal received. A
possible workaround is using ' exit'.

However POSIX does allow this type of behavior if the parameters are all
integers. Fix the handling for this and clarify its support in the manpage
since it is specifically allowed by POSIX.

Differential Revision:	https://reviews.freebsd.org/D2325
Reviewed by:	jilles
MFC after:	2 weeks
---
 bin/sh/sh.1                    |  5 ++---
 bin/sh/tests/builtins/Makefile |  2 ++
 bin/sh/tests/builtins/trap15.0 |  5 +++++
 bin/sh/tests/builtins/trap16.0 | 20 ++++++++++++++++++++
 bin/sh/trap.c                  |  2 +-
 5 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 bin/sh/tests/builtins/trap15.0
 create mode 100644 bin/sh/tests/builtins/trap16.0

diff --git a/bin/sh/sh.1 b/bin/sh/sh.1
index b22a98f01132..e5707c0ff721 100644
--- a/bin/sh/sh.1
+++ b/bin/sh/sh.1
@@ -32,7 +32,7 @@
 .\"	from: @(#)sh.1	8.6 (Berkeley) 5/4/95
 .\" $FreeBSD$
 .\"
-.Dd February 22, 2015
+.Dd April 18, 2015
 .Dt SH 1
 .Os
 .Sh NAME
@@ -2574,8 +2574,7 @@ the former causes the specified signal to be ignored
 and the latter causes the default action to be taken.
 Omitting the
 .Ar action
-is another way to request the default action, for compatibility reasons this
-usage is not recommended though.
+and using only signal numbers is another way to request the default action.
 In a subshell or utility environment,
 the shell resets trapped (but not ignored) signals to the default action.
 The
diff --git a/bin/sh/tests/builtins/Makefile b/bin/sh/tests/builtins/Makefile
index 5f5da4a89077..ad39aacf1be5 100644
--- a/bin/sh/tests/builtins/Makefile
+++ b/bin/sh/tests/builtins/Makefile
@@ -137,6 +137,8 @@ FILES+=		trap11.0
 FILES+=		trap12.0
 FILES+=		trap13.0
 FILES+=		trap14.0
+FILES+=		trap15.0
+FILES+=		trap16.0
 FILES+=		trap2.0
 FILES+=		trap3.0
 FILES+=		trap4.0
diff --git a/bin/sh/tests/builtins/trap15.0 b/bin/sh/tests/builtins/trap15.0
new file mode 100644
index 000000000000..6b9857df3d1a
--- /dev/null
+++ b/bin/sh/tests/builtins/trap15.0
@@ -0,0 +1,5 @@
+# $FreeBSD$
+
+(${SH} -c 'term(){ exit 5;}; trap term TERM; kill -TERM $$') &
+wait >/dev/null 2>&1 $!
+[ $? -eq 5 ]
diff --git a/bin/sh/tests/builtins/trap16.0 b/bin/sh/tests/builtins/trap16.0
new file mode 100644
index 000000000000..3d70cce8a721
--- /dev/null
+++ b/bin/sh/tests/builtins/trap16.0
@@ -0,0 +1,20 @@
+# $FreeBSD$
+
+traps=$(${SH} -c 'trap "echo bad" 0; trap - 0; trap')
+[ -z "$traps" ] || exit 1
+traps=$(${SH} -c 'trap "echo bad" 0; trap "" 0; trap')
+expected_traps=$(${SH} -c 'trap "" EXIT; trap')
+[ "$traps" = "$expected_traps" ] || exit 2
+traps=$(${SH} -c 'trap "echo bad" 0; trap 0; trap')
+[ -z "$traps" ] || exit 3
+traps=$(${SH} -c 'trap "echo bad" 0; trap -- 0; trap')
+[ -z "$traps" ] || exit 4
+traps=$(${SH} -c 'trap "echo bad" 0 1 2; trap - 0 1 2; trap')
+[ -z "$traps" ] || exit 5
+traps=$(${SH} -c 'trap "echo bad" 0 1 2; trap "" 0 1 2; trap')
+expected_traps=$(${SH} -c 'trap "" EXIT HUP INT; trap')
+[ "$traps" = "$expected_traps" ] || exit 6
+traps=$(${SH} -c 'trap "echo bad" 0 1 2; trap 0 1 2; trap')
+[ -z "$traps" ] || exit 7
+traps=$(${SH} -c 'trap "echo bad" 0 1 2; trap -- 0 1 2; trap')
+[ -z "$traps" ] || exit 8
diff --git a/bin/sh/trap.c b/bin/sh/trap.c
index 4a185b4874f5..f562e2785a58 100644
--- a/bin/sh/trap.c
+++ b/bin/sh/trap.c
@@ -183,7 +183,7 @@ trapcmd(int argc __unused, char **argv)
 		return 0;
 	}
 	action = NULL;
-	if (*argv && sigstring_to_signum(*argv) == -1) {
+	if (*argv && !is_number(*argv)) {
 		if (strcmp(*argv, "-") == 0)
 			argv++;
 		else {