block - Lock files in PHP without using flock -

when user upload file(users can upload multiple files)

exec('nohup php /main/apache2/work/upload/run.php &'); 

i using nohup needs executed in end.

in original design run.php scans directory using scandir everytime it's executed. exclusive lock lock_ex on file using flock , use lock_nb skip file if has lock , go next one. if file has lock //do logic. problem server missing fcntl() library , since flock uses library execute locking mechanism, flock won't work @ moment. it's going take month or 2 installed(i have no control on that).

so work around have temporary file lock.txt acts lock. if filename exists in lock.txt skip file , go next one.

$dir = "/main/apache2/work/upload/files/"; $files = scandir($dir); $filename = "lock.txt";  for($i=0; $i<count($files); $i++)  {        if(substr(strrchr($files[$i],'.csv'),-4) == '.csv')     {                    if($file_handle = fopen("$filename", "rb"))         {             while(!feof($file_handle))             {                 $line = fgets($file_handle);                 $line = rtrim($line);                 if($line == "")                 {                     break;                 }                 else                 {                     if($files[$i] == $line)                     {                         echo "reading lock: ".$line."</br>";                         $i++; //go next file                     }                 }              }             fclose($file_handle);         }          if($i >= count($files))         {             die("$i end of file");         }          if($file_handle = fopen("$filename", "a+"))         {             if(is_writable($filename))             {                                $write = fputs($file_handle, "$files[$i]"."\n");                 //do logic                  //delete file name - stuck here                  fclose($file_handle);             }          }      }     else     {         //do nothing     } } 

how can delete filename lock.txt?

more importantly, there better way lock file in php without using flock?

having shared lock database moves locking problem file; doesn't solve it.

a better solution use 1 lock file per real file. if want lock access myfile.csv check file_exists('myfile.csv.lock') , touch('myfile.csv.lock') if doesn't exist. , unlink('myfile.csv.lock') when done.

now, there possible race-condition between file_exists() , touch(), can mitigated storing pid in file , checking if getmypid() indeed process holding lock.