implement set -o pipefail

check.t

@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.610 2013/05/02 20:21:38 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.611 2013/05/02 20:28:10 tg Exp $
 # $OpenBSD: bksl-nl.t,v 1.2 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: history.t,v 1.5 2001/01/28 23:04:56 niklas Exp $
 # $OpenBSD: read.t,v 1.3 2003/03/10 03:48:16 david Exp $
@@ -6294,6 +6294,28 @@ expected-stdout:
 	PIPESTATUS[0]=0
 	8 PIPESTATUS[0]=0 PIPESTATUS[1]=0 .
 ---
+name: pipeline-4
+description:
+	Check that "set -o pipefail" does what it's supposed to
+stdin:
+	echo 1 "$("$__progname" -c '(exit 12) | (exit 23) | (exit 42); echo $?')" .
+	echo 2 "$("$__progname" -c '! (exit 12) | (exit 23) | (exit 42); echo $?')" .
+	echo 3 "$("$__progname" -o pipefail -c '(exit 12) | (exit 23) | (exit 42); echo $?')" .
+	echo 4 "$("$__progname" -o pipefail -c '! (exit 12) | (exit 23) | (exit 42); echo $?')" .
+	echo 5 "$("$__progname" -c '(exit 23) | (exit 42) | :; echo $?')" .
+	echo 6 "$("$__progname" -c '! (exit 23) | (exit 42) | :; echo $?')" .
+	echo 7 "$("$__progname" -o pipefail -c '(exit 23) | (exit 42) | :; echo $?')" .
+	echo 8 "$("$__progname" -o pipefail -c '! (exit 23) | (exit 42) | :; echo $?')" .
+expected-stdout:
+	1 42 .
+	2 0 .
+	3 42 .
+	4 0 .
+	5 0 .
+	6 1 .
+	7 42 .
+	8 0 .
+---
 name: persist-history-1
 description:
 	Check if persistent history saving works

jobs.c

@@ -1,7 +1,8 @@
 /*	$OpenBSD: jobs.c,v 1.38 2009/12/12 04:28:44 deraadt Exp $	*/
 
 /*-
- * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012
+ * Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011,
+ *		 2012, 2013
  *	Thorsten Glaser <tg@mirbsd.org>
  *
  * Provided that these terms and disclaimer and all copyright notices
@@ -22,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.95 2013/04/01 02:37:50 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/jobs.c,v 1.96 2013/05/02 20:28:12 tg Exp $");
 
 #if HAVE_KILLPG
 #define mksh_killpg		killpg
@@ -1220,6 +1221,8 @@ j_waitj(Job *j,
 			    ARRAY | INT_U | AINDEX;
  got_array:
 			vp->val.i = proc_errorlevel(p);
+			if (Flag(FPIPEFAIL) && vp->val.i)
+				rv = vp->val.i;
 			p = p->next;
 		}
 	}

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.313 2013/05/02 15:33:30 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.314 2013/05/02 20:28:13 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.146 2013/03/18 11:10:52 mpi Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
@@ -514,7 +514,9 @@ token to form pipelines, in which the standard output of each command but the
 last is piped (see
 .Xr pipe 2 )
 to the standard input of the following command.
-The exit status of a pipeline is that of its last command.
+The exit status of a pipeline is that of its last command, unless the
+.Ic pipefail
+option is set (see there).
 All commands of a pipeline are executed in separate subshells;
 this is allowed by POSIX but differs from both variants of
 .At
@@ -4177,6 +4179,9 @@ See the
 and
 .Ic pwd
 commands above for more details.
+.It Fl o Ic pipefail
+Make the exit status of a pipeline (before logically complementing) the
+rightmost non-zero errorlevel, or zero if all commands exited with zero.
 .It Fl o Ic posix
 Enable a somewhat more
 .Px

sh_flags.h

@@ -1,5 +1,5 @@
 #if defined(SHFLAGS_DEFNS)
-__RCSID("$MirOS: src/bin/mksh/sh_flags.h,v 1.13 2013/05/02 20:21:45 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh_flags.h,v 1.14 2013/05/02 20:28:15 tg Exp $");
 #define FN(sname,cname,ochar,flags)	/* nothing */
 #elif defined(SHFLAGS_ENUMS)
 #define FN(sname,cname,ochar,flags)	cname,
@@ -88,6 +88,9 @@ FN("nounset", FNOUNSET, 'u', OF_ANY)
 /* ./.	don't do logical cds/pwds (non-standard) */
 FN("physical", FPHYSICAL, 0, OF_ANY)
 
+/* ./.	errorlevel of a pipeline is the rightmost nonzero value */
+FN("pipefail", FPIPEFAIL, 0, OF_ANY)
+
 /* ./.	adhere more closely to POSIX even when undesirable */
 FN("posix", FPOSIX, 0, OF_ANY)