dev-chiefworks
44 lines
1.1 KiB
PHP
44 lines
1.1 KiB
PHP
<?php
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// sudo mkdir /run/php
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// sudo chmod a+rw /run/php
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function lock_pid_file($fn=NULL) {
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if ($fn==NULL) {
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$fn = '/run/php/'.basename($_SERVER['PHP_SELF'], '.php').'.pid';
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}
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$lock_file = fopen($fn, 'c');
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$got_lock = flock($lock_file, LOCK_EX | LOCK_NB, $wouldblock);
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if ($lock_file === false || (!$got_lock && !$wouldblock)) {
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throw new Exception(
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"Unexpected error opening or locking lock file. Perhaps you " .
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"don't have permission to write to the lock file or its " .
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"containing directory?"
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);
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}
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else if (!$got_lock && $wouldblock) {
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exit("Another instance is already running; terminating.\n");
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}
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// Lock acquired; let's write our PID to the lock file for the convenience
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// of humans who may wish to terminate the script.
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ftruncate($lock_file, 0);
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fwrite($lock_file, getmypid() . "\n");
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/*
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The main body of your script goes here.
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*/
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return $lock_file;
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}
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function unlock_pid_file($lock_file) {
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// All done; we blank the PID file and explicitly release the lock
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// (although this should be unnecessary) before terminating.
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ftruncate($lock_file, 0);
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flock($lock_file, LOCK_UN);
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}
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/*
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vi:ts=2
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*/
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