+ $this->procsToStart = $numProcs;
+ $this->flags = $flags;
+ }
+
+ /**
+ * Start the child processes.
+ *
+ * This should only be called from the command line. It should be called
+ * as early as possible during execution.
+ *
+ * This will return 'child' in the child processes. In the parent process,
+ * it will run until all the child processes exit or a TERM signal is
+ * received. It will then return 'done'.
+ */
+ public function start() {
+ // Trap SIGTERM
+ pcntl_signal( SIGTERM, array( $this, 'handleTermSignal' ), false );
+
+ do {
+ // Start child processes
+ if ( $this->procsToStart ) {
+ if ( $this->forkWorkers( $this->procsToStart ) == 'child' ) {
+ return 'child';
+ }
+ $this->procsToStart = 0;
+ }
+
+ // Check child status
+ $status = false;
+ $deadPid = pcntl_wait( $status );
+
+ if ( $deadPid > 0 ) {
+ // Respond to child process termination
+ unset( $this->children[$deadPid] );
+ if ( $this->flags & self::RESTART_ON_ERROR ) {
+ if ( pcntl_wifsignaled( $status ) ) {
+ // Restart if the signal was abnormal termination
+ // Don't restart if it was deliberately killed
+ $signal = pcntl_wtermsig( $status );
+ if ( in_array( $signal, self::$restartableSignals ) ) {
+ echo "Worker exited with signal $signal, restarting\n";
+ $this->procsToStart++;
+ }
+ } elseif ( pcntl_wifexited( $status ) ) {
+ // Restart on non-zero exit status
+ $exitStatus = pcntl_wexitstatus( $status );
+ if ( $exitStatus != 0 ) {
+ echo "Worker exited with status $exitStatus, restarting\n";
+ $this->procsToStart++;
+ } else {
+ echo "Worker exited normally\n";
+ }
+ }
+ }
+ // Throttle restarts
+ if ( $this->procsToStart ) {
+ usleep( 500000 );
+ }
+ }
+
+ // Run signal handlers
+ if ( function_exists( 'pcntl_signal_dispatch' ) ) {
+ pcntl_signal_dispatch();
+ } else {
+ declare (ticks=1) { $status = $status; }
+ }
+ // Respond to TERM signal
+ if ( $this->termReceived ) {
+ foreach ( $this->children as $childPid => $unused ) {
+ posix_kill( $childPid, SIGTERM );
+ }
+ $this->termReceived = false;
+ }
+ } while ( count( $this->children ) );
+ pcntl_signal( SIGTERM, SIG_DFL );
+ return 'done';