Re: How to find a bug: is_link troubles

Hi again, Thanks for your reply. I think perhaps I've not been totally clear on my last e-mail. The directory does exist. If this dir or symlink would not exist, the code would have outputted "Couldn't create the link". The fact that is goes well right after the symlink is just created, is indeed the cause of the stat cache. But the actual problem is that the symlink is not recognized as a symlink. It seems to be dereferenced by functions like 'lstat', 'is_link' and 'filetype'. And that isn't supposed to happen. The problem has probably something to do with my system in combination with apache/php. So I guess reporting it as a bug won't do, because it will simply be filed under 'works here'. If anybody has any clue what is going on here, please let me know. For the record I've updated to CVS snapshot of May 10, 2007 14:30 GMT, but it didn't work with older version as well. Let me give another example, with which I hope I can make the problem clearer. ------------ Script: <? $symlink = '/tmp/link-test'; $target = '/tmp/pear'; if (!file_exists($target)) trigger_error("Target '$target' does not exist", E_USER_ERROR); if (file_exists($symlink) && !unlink($symlink)) trigger_error("Could not delete '$symlink'", E_USER_ERROR); symlink($target, $symlink); clearstatcache(); /* This should output 'link' */ echo filetype($symlink), "\n"; /* This should output 'link' */ echo is_link($symlink) ? 'link' : 'not a link', "\n"; /* This should output 'differ' */ echo lstat($symlink) === stat($target) ? 'same' : 'differ'; ?> Expected: link link differ Actual: dir not a link same ------------ Thanks for any help, Arnold Tijnema ! wrote:

On 5/2/07, Arnold Daniels <info@adaniels.nl> wrote:

Hi, I've got a bug with is_link and lstats. Any symlinks not created in the current session, will not be read. This only occurs in the Apache 2 SAPI version, not in the CLI version. Script: <?

    $symlink = '/tmp/link-test';
    if (file_exists($symlink)) unlink($symlink);
    symlink('/tmp/pear', $symlink);
    echo (file_exists($symlink) ? is_link($symlink) ? "Correct" : "ERROR" :

"Couldn't create the link"), "<br/>\n";

    $symlink = '/tmp/link-persist';
    if (!file_exists($symlink)) symlink('/tmp/pear', $symlink);
    echo (file_exists($symlink) ? is_link($symlink) ? "Correct" : "ERROR" :

"Couldn't create the link"), "<br/>\n"; ?> First run:

    Correct
    Correct

Second run:

    Correct
    ERROR

Next runs:

    Correct
    ERROR

I've recently start using the daily snapshots op PHP, but I also tried it on version 5.2.1, which shows the same result. It used to work just fine, so I'm sure this isn't the expected result. I've recently upgraded from Ubuntu Edgy (6.10) to Feisty (7.04), with kernel and apache update, so I believe that the problem is related to that. I've straced the process (see attachment), but I can't pinpoint the problem. This is a big issue for me, can anyone point me in the right direction to find the source of this problem. Thanks, Arnold

<snip> Well, I've also tested this code, and it does work fine. BUT if /tmp/pear doesn't exists, what i had at first, then file_exists returns false, because file_exists follows symlinks, and the symlink pointed to nothing. So if you're sure that $symlink is a link, then it might be better to check it with is_link. Also, the is_link function is cached, so you might want to add one or more clearstatcache() in your script. I checked your strace also, but it doesn't look like there's a bug. But I've never studied on the PHP core so.... Well, if above doesn't help you, then one of the "real experts" needs to look at it :) Tijnema