Simple PHP lock file function

Could anyone please help with a PHP lock file function ?

I want to create a symlink when a URL like this is followed (with the filename being the characters after "file="):

http://www.blah.com/download.p开发者_运维问答hp?file=zFZpj4b2AkEFz%2B3O

and then I need to deny access if the symlink exists ... but I'm out of my dept !

Help greatly appreciated.

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You can execute a shell script with chmod to restrict access. Use exec function in php.

ln -s mysymlink
if [  -f mysymlink ] then
    chmod 000 filenametobedenied
fi 

this could be the shell script save it in the document root as filecheck.sh and run this script throgh the exec('filecheck.sh') function

---

See this example (comments are mine) taken from the PHP Manual for is_link():

<?php
$link = 'uploads';

if (is_link($link)) { // check if the link exists
    echo(readlink($link)); // echo out path this link points to
    // this is where you ban access
} else {
    symlink('uploads.php', $link); // create the symlink
}
?>

---

ln -s mysymlink
if [  -f mysymlink ] then
    chmod 000 filenametobedenied
fi 

this could be the shell script save it in the document root as filecheck.sh and run this script throgh the exec('filecheck.sh') function