Blob Blame Raw
From 35608a1658fe75c79ca53d96aea6cf7cb2a98615 Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Thu, 9 May 2019 09:52:30 +1000
Subject: [PATCH] (perl #122112) a simpler fix for pclose() aborted by a signal
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This change results in a zombie child process for the lifetime of
the process, but I think that's the responsibility of the signal
handler that aborted pclose().

We could add some magic to retry (and retry and retry) waiting on
child process as we rewind (since there's no other way to remove
the zombie), but the program has chosen implicitly to abort the
wait() done by pclose() and it's best to honor that.

If we do choose to retry the wait() we might be blocking an attempt
by the process to terminate, whether by exit() or die().

If a program does need more flexible handling there's always
pipe()/fork()/exec() and/or the various event-driven frameworks on
CPAN.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 doio.c      | 12 +++++++++++-
 t/io/pipe.t |  2 --
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/doio.c b/doio.c
index 0cc4e55404..05a06968dc 100644
--- a/doio.c
+++ b/doio.c
@@ -1779,7 +1779,17 @@ Perl_io_close(pTHX_ IO *io, GV *gv, bool not_implicit, bool warn_on_fail)
 
     if (IoIFP(io)) {
 	if (IoTYPE(io) == IoTYPE_PIPE) {
-	    const int status = PerlProc_pclose(IoIFP(io));
+            PerlIO *fh = IoIFP(io);
+            int status;
+
+            /* my_pclose() can propagate signals which might bypass any code
+               after the call here if the signal handler throws an exception.
+               This would leave the handle in the IO object and try to close it again
+               when the SV is destroyed on unwind or global destruction.
+               So NULL it early.
+            */
+            IoOFP(io) = IoIFP(io) = NULL;
+	    status = PerlProc_pclose(fh);
 	    if (not_implicit) {
 		STATUS_NATIVE_CHILD_SET(status);
 		retval = (STATUS_UNIX == 0);
diff --git a/t/io/pipe.t b/t/io/pipe.t
index 1d01db6af6..fc3071300d 100644
--- a/t/io/pipe.t
+++ b/t/io/pipe.t
@@ -255,9 +255,7 @@ close \$fh;
 PROG
     print $prog;
     my $out = fresh_perl($prog, {});
-    $::TODO = "not fixed yet";
     cmp_ok($out, '!~', qr/refcnt/, "no exception from PerlIO");
-    undef $::TODO;
     # checks that that program did something rather than failing to
     # compile
     cmp_ok($out, '=~', qr/Died at/, "but we did get the exception from die");
-- 
2.20.1