#37619 [Opn->Asn]: proc_open() closes stdin on fork() failure
ID: 37619
Updated by: tony2001@php.net
Reported By: jdolecek at NetBSD dot org
-Status: Open
+Status: Assigned
Bug Type: Program Execution
Operating System: Any UNIX-like, Netware
PHP Version: 5.1.4
-Assigned To:
+Assigned To: wez
Previous Comments:
------------------------------------------------------------------------
[2006-05-31 21:34:18] jdolecek at NetBSD dot org
I think bash uses ulimit -u rathern then ulimit -p for max user
processes (I've used ksh).
------------------------------------------------------------------------
[2006-05-31 18:26:11] mike@php.net
Could you please provide a more portable reproduce case?
mike@honeybadger:~/build/php-5.2-debug$ bash /tmp/run.sh
/tmp/run.sh: line 1: ulimit: pipe size: cannot modify limit: Invalid
argument
sh: line 0: echo: write error: Bad file descriptor
test
------------------------------------------------------------------------
[2006-05-28 20:30:32] jdolecek at NetBSD dot org
Description:
------------
The block spawning the child process for both Netware and UNIX-like OS
contains this block in failure case:
if (child < 0) {
/* failed to fork() */
/* clean up all the descriptors */
for (i = 0; i < ndesc; i++) {
close(descriptors[i].childend);
close(descriptors[i].parentend);
}
...
}
parentend is filled only for pipes, for 'file'
handles it's not filled, and left '0' as initialized
by memset() in proc_open.c line 537.
So, if proc_open() was called with descriptorspec
using 'file' and the fork() call fails, this results
in closing descriptor 0.
Quick fix is to only close parentend if it's non-zero, such as:
--- ext/standard/proc_open.c.orig 2006-05-28 21:51:09.000000000
+0200
+++ ext/standard/proc_open.c
@@ -796,7 +796,8 @@ PHP_FUNCTION(proc_open)
/* clean up all the descriptors */
for (i = 0; i < ndesc; i++) {
close(descriptors[i].childend);
- close(descriptors[i].parentend);
+ if (descriptors[i].parentend)
+ close(descriptors[i].parentend);
}
php_error_docref(NULL TSRMLS_CC, E_WARNING, "procve
failed - %s", strerror(errno));
goto exit_fail;
@@ -863,7 +864,8 @@ PHP_FUNCTION(proc_open)
/* clean up all the descriptors */
for (i = 0; i < ndesc; i++) {
close(descriptors[i].childend);
- close(descriptors[i].parentend);
+ if (descriptors[i].parentend)
+ close(descriptors[i].parentend);
}
php_error_docref(NULL TSRMLS_CC, E_WARNING, "fork
failed - %s", strerror(errno));
Reproduce code:
---------------
It's necessary to setup process limit via ulimit so that running the
php script gets last allowed slot:
> echo test > tst
> ulimit -p pgrep -u "\id -u\" | wc -l
> php script.php < tst
script.php:
<?php
$p = proc_open("echo hello", array(0 => array('file', '/dev/null',
'r'), 1 =>
array('pipe', 'r')), $pipes1);
echo file_get_contents("php://stdin")."\n";
Expected result:
----------------
PHP Warning: proc_open(): fork failed - Resource temporarily
unavailable in /usr/home/dolecek/tmp/proc3.php on line 4
test
Actual result:
--------------
PHP Warning: proc_open(): fork failed - Resource temporarily
unavailable in /usr/home/dolecek/tmp/proc3.php on line 4
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=37619&edit=1
Thread (5 messages)