Bug #63240 [Asn->Csd]: stream_get_line return contains delimiter string

From: Date: Fri, 12 Oct 2012 18:23:20 +0000
Subject: Bug #63240 [Asn->Csd]: stream_get_line return contains delimiter string
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-174053@lists.php.net to get a copy of this message
Edit report at https://bugs.php.net/bug.php?id=63240&edit=1

 ID:                 63240
 Updated by:         cataphract@php.net
 Reported by:        scope at planetavent dot de
 Summary:            stream_get_line return contains delimiter string
-Status:             Assigned
+Status:             Closed
 Type:               Bug
 Package:            Streams related
 Operating System:   Windows Server 2008 / RHEL 6.2
 PHP Version:        5.3.17
 Assigned To:        cataphract
 Block user comment: N
 Private report:     N

 New Comment:

Automatic comment on behalf of glopes@nebm.ist.utl.pt
Revision: http://git.php.net/?p=php-src.git;a=commit;h=76601c4fd1052bd46e8db4addb1bb9dd3b001f98
Log: Fix bug #63240 on stream_get_line()


Previous Comments:
------------------------------------------------------------------------
[2012-10-09 21:14:04] cataphract@php.net

Thanks, I'll commit this tomorrow.

As to your other comment on the list about the bool(false) return instead of an empty string for an
empty file, that was a bug fix. A return of "" would indicate an empty line. The result is
now corect:

$ php -r '$fd = fopen("php://temp", "r+"); var_dump(stream_get_line($fd,
10, "MM"));'
bool(false)
$ php -r '$fd = fopen("php://temp", "r+"); fwrite($fd, "MM");
rewind($fd); var_dump(stream_get_line($fd, 10, "MM"), stream_get_line($fd, 10,
"MM"));
string(0) ""
bool(false)

------------------------------------------------------------------------
[2012-10-09 09:02:54] datibbaw@php.net

Added a patch that will apply to 5.4.4

------------------------------------------------------------------------
[2012-10-09 09:02:18] datibbaw@php.net

The following patch has been added/updated:

Patch Name: getrecord-delimiter-search-fix
Revision:   1349773338
URL:        https://bugs.php.net/patch-display.php?bug=63240&patch=getrecord-delimiter-search-fix&revision=1349773338

------------------------------------------------------------------------
[2012-10-09 03:35:35] datibbaw@php.net

Reduced test:

  $file = __DIR__ . '/input_dummy.txt';
  $data = str_repeat( '.', 8189 ) . 'MMMM';
  file_put_contents( $file, $data );
  $fh = fopen( $file, "rb" );
  $delimiter = "MM";

  stream_get_line($fh, 4096, $delimiter);
  stream_get_line($fh, 4096, $delimiter);
  if ($delimiter === stream_get_line($fh, 4096, $delimiter)) {
    echo "BROKEN";
  } else {
    echo "OK";
  }
  fclose($fh);
  unlink($file);

The amount of dots seems to be related to the used buffer length:

(<number-of-dots> + 3) % (<buffer-length> x 2) == 0

The length of the delimiter also seems to play a role, but I'm not sure what 
that would be.

------------------------------------------------------------------------
[2012-10-08 16:03:38] scope at planetavent dot de

Description:
------------
On specific file input stream_get_line returns a "line" that actually contains the
delimiter.

PHP 5.3.10 does not show this problem, PHP versions from 5.3.11 to 5.3.17 do. PHP 5.4.7 seems to be
affected as well.

Bug #44607 seems to be related, but was fixed long time ago.

Test script:
---------------
<?php
$file = __DIR__ . '/input_dummy.txt';
$data = str_repeat( '.', 8184 ) . 'MM' . str_repeat( '.', 8190 ) .
'MM' . str_repeat( '.', 8128 ) . 'MM' . str_repeat( '.', 61
) . 'MM' . str_repeat( '.', 20 );
file_put_contents( $file, $data );
$fh = fopen( $file, "rb" );
$delimiter = "MM";

while ( !feof( $fh ) )
{
    $before = ftell( $fh );
    $line = stream_get_line( $fh, 4096, $delimiter );
    $after = ftell( $fh );
    
    if ( strpos( $line, $delimiter  ) !== false )
    {
        echo "found delimiter in return! ($before / $after)\n$line";
		exit;
    }
}

echo "ok\n";

Expected result:
----------------
ok

Actual result:
--------------
found delimiter in return! (24508 / 24591)
.............................................................MM....................


------------------------------------------------------------------------



-- 
Edit this bug report at https://bugs.php.net/bug.php?id=63240&edit=1


Thread (8 messages)

« previous php.bugs (#174053) next »