#20180 [NEW]: can only read 4096 bytes of stdout from proc_open

From: kims@contrail.com.au Operating system: Debian GNU/Linux PHP version: 4CVS-2002-10-30 PHP Bug Type: Apache2 related Bug description: can only read 4096 bytes of stdout from proc_open When using proc_open() with a set of pipes to read the output of a process, only the first 4096 bytes of the pipe are read when using PHP under Apache. When running the same script using php-cgi on the command line, the complete output is returned. Hence, this seems to be an PHP/Apache problem, although admittedly it could be a proc_open() or fread() problem, or an apache2 problem. I'm using the latest apache2 debs from Debian unstable on ppc. Here is a script that reproduces the problem for me. It creates a tempfile, writes more than 4096 bytes of data to it, then tries to read it all back via a pipe from /bin/cat (run with proc_open). <? header('Content-type: text/plain'); $path = "/tmp/foo"; # data to write to temporary file $data = "foo"; # beef up the size of data so it's > 4096 bytes for ($i = 0; $i < 16; $i++) $data .= $data; # write the data to the file $fh = fopen($path, "w"); fwrite($fh, $data); fclose($fh); # set up a process using proc_open to cat the file to stdout $proc = proc_open( 'cat /tmp/foo', array( 0 => array("pipe", "r"), 1 => array("pipe", "w"), 2 => array("pipe", "w") ), $pipes ); # read data from cat's stdout into $out while (!feof($pipes[1])) $out .= fread($pipes[1], 1024); # number of bytes read successfully echo "read: " . strlen($out) . " bytes.\n"; # check if this represents the whole file if (strlen($out) != strlen($data)) echo "didn't read all " . strlen($data) . " bytes of file.\n"; # close pipes from proc_open fclose($pipes[0]); fclose($pipes[1]); fclose($pipes[2]); # close process proc_close($proc); # delete temp file unlink($path); ?> output from php-cgi: Status: 200 X-Powered-By: PHP/4.3.0-dev Content-type: text/plain read: 196608 bytes. output when run via apache: read: 4096 bytes. didn't read all 196608 bytes of file. -- Edit bug report at http://bugs.php.net/?id=20180&edit=1 -- Try a CVS snapshot: http://bugs.php.net/fix.php?id=20180&r=trysnapshot Fixed in CVS: http://bugs.php.net/fix.php?id=20180&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=20180&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=20180&r=needtrace Try newer version: http://bugs.php.net/fix.php?id=20180&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=20180&r=support Expected behavior: http://bugs.php.net/fix.php?id=20180&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=20180&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=20180&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=20180&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=20180&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=20180&r=dst IIS Stability: http://bugs.php.net/fix.php?id=20180&r=isapi