From: Niko Tyni <ntyni@debian.org>
Date: Mon, 26 Jan 2009 12:14:36 +0000 (+0200)
Subject: setpgrp() should extend the stack before modifying it
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=1f200948c4c45a9bc088451dd377e4ab8733c722;p=p5sagit%2Fp5-mst-13.2.git

setpgrp() should extend the stack before modifying it

As reported by Marcin Owsiany in <http://bugs.debian.org/512796>,
invoking setpgrp without any arguments could corrupt the stack.
---

diff --git a/MANIFEST b/MANIFEST
index 5713bde..2a8f702 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -4120,6 +4120,7 @@ t/op/re_tests			Regular expressions for regexp.t
 t/op/reverse.t			See if reverse operator works
 t/op/runlevel.t			See if die() works from perl_call_*()
 t/op/rxcode.t			See if /(?{ code })/ works
+t/op/setpgrpstack.t		See if setpgrp works
 t/op/sleep.t			See if sleep works
 t/op/smartmatch.t		See if the ~~ operator works
 t/op/sort.t			See if sort works
diff --git a/pp_sys.c b/pp_sys.c
index cfbf918..0d2c970 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -4318,6 +4318,7 @@ PP(pp_setpgrp)
     if (MAXARG < 2) {
 	pgrp = 0;
 	pid = 0;
+	XPUSHi(-1);
     }
     else {
 	pgrp = POPi;
diff --git a/t/op/setpgrpstack.t b/t/op/setpgrpstack.t
new file mode 100644
index 0000000..31f498e
--- /dev/null
+++ b/t/op/setpgrpstack.t
@@ -0,0 +1,16 @@
+#!./perl -w
+
+BEGIN {
+    chdir 't' if -d 't';
+    @INC = '../lib';
+    require './test.pl';
+}
+
+use Config;
+plan tests => 2;
+
+SKIP: {
+    skip "setpgrp() is not available", 2 unless $Config{d_setpgrp};
+    ok(!eval { package A;sub foo { die("got here") }; package main; A->foo(setpgrp())});
+    ok($@ =~ /got here/, "setpgrp() should extend the stack before modifying it");
+}