Append data to tar file using PHP-PHAR - php

Question

I'm using the following code to create and append data to a tar-archive in PHP. The problem is that phar does not use an exclusive lock on the tar-file causing problem when I have atomic writes to the same file.
function phar_put_contents($fname, $archive, $data) {
$i=0;
do {
$fp = #fopen($archive.'.lock', 'w');
if(!$fp) {
usleep(25);
continue;
}
if(flock($fp, LOCK_EX)) {
try{
$myPhar = new PharData($archive.'.tar',0);
$myPhar[$fname] = $data;
$myPhar->stopBuffering();
flock($fp, LOCK_UN) && #fclose($fp);
#unlink($archive.'.lock');
return true;
} catch (Exception $e) {
error_log($e->getMessage()." in ".$e->getFile().":".$e->getLine(),0);
unset($e);
#flock($fp, LOCK_UN) && #fclose($fp);
}
}
} while ($i++<8);
return false;
}
Using a look file seems to be a "good" solution but it's not optimal since my archives gets currupted quite frequently.

Answer 1

Ok, it seems like the Phar and PharData classes in PHP is somewhat unfinished, they neither have lock() nor close() making my approach for external locking nonworking..
The following code is what I used to try to have a function that appends data to a tar archive.
function phar_put_contents($fname, $archive, $data) {
$i=0;
do {
$fp = #fopen($archive.'.lock', 'w');
if(!$fp) {
usleep(25);
continue;
}
if(flock($fp, LOCK_EX)) {
try{
file_put_contents('/tmp/'.$fname, $data);
$tarCmd = "tar ". (file_exists($archive.".tar") ? "-rf ":"-cf ") .$archive.".tar -C /tmp ".$fname;
exec($tarCmd, $result, $status);
if($status!=0)
throw new Exception($tarCmd . implode($result, "\n"));
#unlink('/tmp/'.$fname);
flock($fp, LOCK_UN) && #fclose($fp);
#unlink($archive.'.lock');
return true;
} catch (Exception $e) {
error_log($e->getMessage()." in ".$e->getFile().":".$e->getLine(),0);
unset($e);
#flock($fp, LOCK_UN) && #fclose($fp);
}
}
} while ($i++<8);
return false;
}
Note that I'm using exec() and calls the external version of tar. This were a necessity since Phar does very unreliable flushes to the archive, making the tar-file broken since two instances of the code can modify the same file at the same time.