php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #20863 md5_file() and exec() freeze
Submitted: 2002-12-06 10:38 UTC Modified: 2002-12-06 18:29 UTC
From: mike dot duncan at sonopress dot com Assigned:
Status: Not a bug Package: Filesystem function related
PHP Version: 4CVS-2002-12-06 (stable) OS: SuSE 7.3 Pro
Private report: No CVE-ID: None
View Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: mike dot duncan at sonopress dot com
New email:
PHP Version: OS:

 

 [2002-12-06 10:38 UTC] mike dot duncan at sonopress dot com 
Here is my src:

--------------------
$files = array();
$dirs = array();

function getMD5OfFile($f)  {
  return md5_file($f);
  //return exec("md5sum ".$f." | awk '{print $1}'");
}

function getFiles($d)  {
  global $files, $dirs;
  clearstatcache();
        
  if($dir = @opendir($d))  {
    while(($file = @readdir($dir)) !== false)  {
      if(($file != ".") && ($file != ".."))  {
        if(is_dir($d."/".$file)) $dirs[] = $d."/".$file;
        elseif(is_file($d."/".$file) && (substr($file,0,1) != ".")) $files[] = $d."/".$file;
      }               
    }
  }
}

/** Get files for directories **/
getFiles("/home/webdev");
while(($dir = array_shift($dirs)) !== null)  {
  getFiles($dir);
}

/** Ouptut findings **/
while(($file = array_shift($files)) !== null)  {
  echo $file.": ". getMD5FromFile($file) ."\n";
}

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

I first tried this with v4.2.1. What I am trying to do is get the MD5 for every file within the filesystem. Unfortunately this code freezes after about 20 or so files (md5_file() or exec() returns ok until then). If I uncomment the exec() return and comment the md5_file() return, the script hangs at exactly the same spot. If comment both out and run the script without md5'ing any files, I get a listing of all files (no problem). 

I have also tried replacing the md5_file() code with one that was listed here http://www.php.net/manual/en/function.md5-file.php that will read the file into a variable and do a md5() on that var. Unfortunately I got a FATAL: emalloc() error using that method. 

Finally, I tried getting the upgrading to v4.3.0-dev (latest snapshot from snaps) and got the same results.

I cannot figure out why this hangs and does not bomb out. I think it has something to do with maybe a cache of some sort or the memory buffers are filling up. Maybe even something to with how I am traversing the array of directories? But then, why would it work without the md5 cals? I do not know, but I thought I would post it here and see what you guys think. TIA.

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2002-12-06 10:44 UTC] mike dot duncan at sonopress dot com 
BTW, The files I am examining are all text.
 [2002-12-06 11:06 UTC] iliaa@php.net 
Does your PHP have a memory limit?
 [2002-12-06 11:38 UTC] mike dot duncan at sonopress dot com 
I do not have this enabled. My configure line looks like so:

./configure --enable-ftp --with-ldap=/usr/local/openldap --with-mysql=/usr --with-openssl=/usr/local/openssl

I thought for the memory_limit directive to take effect would mean I would to have had to add --enable-momory-limit to the configuration. Has this changed recently (i.e. >= 4.2.1)?
 [2002-12-06 11:41 UTC] mike dot duncan at sonopress dot com 
I also tried adding ini_set("max_execution_time", "180") to the script and it changed nothing. Just to make sure it was not hitting this limit too.
 [2002-12-06 11:45 UTC] iliaa@php.net 
Could you please remove the @ from your script, which block error message and set error repoting level to E_ALL.
Please include any warning messages in your reply.
 [2002-12-06 12:08 UTC] mike dot duncan at sonopress dot com 
I added error_reporting(E_ALL) and got no errors or warnings. I actually do not get anything but the expected output...

/home/webdev/$dir/$file : $md5

...unless I change the md5 calculation to that of the binary one here: http://www.php.net/manual/en/function.md5-file.php.  Then I get a FATAL: emalloc() Could not allocate xxxxx bytes. 

But this is not how I run this script. I always use the md5_file() or exec() functions to calc. the MD5 of the file. 

Other than the expected output, with or without E_ALL set, I get nothing, hanging after about 20 or so md5 calculations.

Can you reproduce this when you copy+paste this and run it?
 [2002-12-06 12:14 UTC] mike dot duncan at sonopress dot com 
This is running as a script, from a shell (i.e. #!/usr/local/bin/php); not as a web app. We are trying to create a script that (scheduled from cron) will create MD5 for all files for a type of tracking system.
 [2002-12-06 12:15 UTC] iliaa@php.net 
Does your directory structure you are doing md5s on, have any recursive symlinks or any symlinks for that matter?
 [2002-12-06 12:32 UTC] mike dot duncan at sonopress dot com 
I am unsure as to what is going on. I do not see any symlinks at all actually. 

When I ran the same script with /usr/bin (no sub-direcories in /usr/bin) it ran fine (slowly, but fine). So this cannot be something referring to a memory buffer or cache. 

It is probably my coding. I appreciate your help very much.
 [2002-12-06 18:29 UTC] sniper@php.net 
Most likely user error since this is the only report about it..
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Mon Jul 07 07:01:33 2025 UTC