# Check if we should not run duplicates, and if so, check if                  # this is a duplicate of a script now running.                  if ($no_duplicates) {                      for ($i = 0; $i < $job_limit; $i++) {                          if ($job_script_no[$i] == $script_no) {                              # $script_no is the script job $i is running, so                              # try again.                              next find_script;                          }                      }                  }                  # We are allowed to run this script.                  last find_script;              }          }      }      # Check to see if we exited due to not being able to find a script too      # many times.      if ($tries == $script_select_tries) {          print STDERR "Unable to find a script to execute for job $slot.\n";          return;      }    } else {        # Select a script deterministically.        $script_no = $slot;    }    # Record that this job is using this script.    $job_script_no[$slot] = $script_no;    # Increment the count of jobs running first, to avoid a race condition    # if it dies between the fork and the time we would increment it.    $jobs_running++;    # Fork a subprocess.    $x = fork();    if (!defined($x)) {        print "fork() failed: $!\n";        # Decrement the count, since we failed to start the job.        $jobs_running--;    } elsif ($x == 0) {        # This is the child process.        # Select ports to use.        $sip_port = $port_base + $port_increment * $slot;        $rtp_port = $rtp_base + $rtp_increment * $slot;        # Assemble the command to be executed.        @command = ($CallScript_program, '-p', $sip_port, '-r', $rtp_port,                    '-l', "Job $slot: ",                    @{$script_args[$job_script_no[$slot]]});        # Print the command we will execute now, so the print isn't affected        # by output redirection.        print "exec(", join(' ', map { "'$_'" } @command), ")\n"            if $debug;        # Sleep the appropriate time.        sleep $fork_sleep;        if ($randomize_time > 0) {            print "Job $slot: pause random $randomize_time (pause ",                  $random_time*1000, ")*\n";            sleep $random_time;        }        # Set up stdin and stdout.        open(STDOUT, ">/dev/null") ||            die "Error opening /dev/null for output: $!\n";        open(STDIN, "<$script_files[$job_script_no[$slot]]") ||            die "Error opening '$script_files[$job_script_no[$slot]]' for input: $!\n";        # Route stderr from subjobs to stderr here (as opposed to routing it        # to stdout as we used to), so errors from the subjobs are easy to        # see.        exec(@command);        die "Error from exec(" . join(' ', map { "'$_'" } @command) .            "): $!\n";    }    # This is the parent process.    $subjob_pid[$slot] = $x;    print "Job $slot: Starting '$script_files[$job_script_no[$slot]]'\n";    $script_counts[$script_no]++;    print "\$subjob_pid[$slot] = $x\n" if $debug;}# Remove from the table the subjob with the pid $pid.# Return the slot number.sub reap_job {    my($pid) = @_;    my($i);    print "\&reap_job($pid)\n" if $debug;    for ($i = 0; $i <= $job_limit; $i++) {        if ($pid == $subjob_pid[$i]) {            print "Job $i: Ending\n";            $subjob_pid[$i] = 0;            $job_script_no[$i] = -1;            print "\$subjob_pid[$i] = 0\n" if $debug;            print "return $i\n" if $debug;            return $i;        }    }    die "Cannot find slot of subjob PID $pid.\n";}# Set up interrupt handler for SIGHUP, which shuts down the run gracefully.sub signal_handler_HUP {    # Set the ending time to now, so the main loop exits.    print "HUP received.\n";    $end_time = time;}# Set up interrupt handler for SIGQUIT, which shuts down the run# immediately, since it does not wait for the jobs to finish.sub signal_handler_QUIT {    my($i, $pid);    print "QUIT received.\n";    # Set the ending time to now, so the main loop exits.    $end_time = time;    # Kill all the jobs.    for ($i = 0; $i <= $job_limit; $i++) {        if ($subjob_pid[$i] != 0) {            print "Job $i: Killing\n";            print "kill -KILL $subjob_pid[$i]\n" if $debug;            kill('KILL', $subjob_pid[$i]);        }    }    # Set the number of jobs to 0, so the finishing-up loop exits.    $jobs_running = 0;}# Process a single command line.# $command is the command line/string.# $id is the identification for error messages.  E.g., "...file... line ..." or# "argument ...".sub process_command {    my($command, $id) = @_;    my(@tokens, $weight, $file, @args);    # Substitute for variables.    chomp $command;    $command =~        s/\${([^}]*)}/defined($variables{$1}) ?                   $variables{$1} :                   die "No value given for variable '$1' in $id\n"/ge;    print "\$command = '$command'\n" if $debug;    # Ignore blank lines.    return if $command =~ m/^\s*$/;    # Ignore comments.    return if $command =~ m/^\s*#/;    # Get the words of the command.    @tokens = split(' ', $command);    print "\@tokens = '", join("' '", @tokens), "'\n" if $debug;    if ($tokens[0] eq 'time') {        # time NNN        $time_limit = $tokens[1];        # Check its syntax.        unless ($time_limit =~ /^(\d+)([smhd]?)$/) {            print STDERR "Invalid time value '$time_limit' in $id\n";            $errors_found++;            return;        }        # Convert the digit string into a number.        $time_limit = $1 + 0;        # Multiply by the right factor.        # Do nothing for 's' and ''.        if ($2 eq 'm') {            $time_limit *= 60;        } elsif ($2 eq 'h') {            $time_limit *= 60 * 60;        } elsif ($2 eq 'd') {            $time_limit *= 24 * 60 * 60;        }        print "\$time_limit = $time_limit\n" if $debug;    } elsif ($tokens[0] eq 'jobs') {        # jobs NNN        $job_limit = $tokens[1] + 0;        unless ($job_limit > 0) {            print STDERR "Invalid job limit '$tokens[1]' in $id\n";            $errors_found++;            return;        }        print "\$job_limit = $job_limit\n" if $debug;    } elsif ($tokens[0] eq 'program') {        # program NAME        $CallScript_program = $tokens[1];        unless ($CallScript_program ne '' && -x $CallScript_program) {            print STDERR "Empty or non-executable program name '$CallScript_program' in $id\n";            $errors_found++;            return;        }        print "\$job_limit = $job_limit\n" if $debug;    } elsif ($tokens[0] eq 'script') {        # script NNN FFF        $weight = $tokens[1] + 0;        $file = $tokens[2];        # The following slice appears to work even if $#tokens == 2.        @args = @tokens[3..$#tokens];        unless ($weight > 0) {            print STDERR "Invalid weight '$tokens[1]' in $id\n";            $errors_found++;            return;        }        unless ($file ne '') {            print STDERR "Must specify script file in $id\n";            $errors_found++;            return;        }        unless (-r $file) {            print STDERR "Cannot read script file '$file' in $id\n";            $errors_found++;            return;        }        push(@script_weights, $weight);        push(@script_files, $file);        push(@script_args, \@args);        push(@script_counts, 0);    } elsif ($tokens[0] eq 'randomize') {        # randomize NNN        $randomize_time = $tokens[1] + 0;        unless ($randomize_time >= 0) {            print STDERR "Invalid randomization time '$tokens[1]' in $id\n";            $errors_found++;            return;        }        print "\$randomize_time = $randomize_time\n" if $debug;    } elsif ($tokens[0] eq 'noduplicates') {        # noduplicates        $no_duplicates = 1;        print "\$no_duplicates = $no_duplicates\n" if $debug;    } elsif ($tokens[0] eq 'nonrandom') {        # nonrandom        $nonrandom = 1;        print "\$nonrandom = $nonrandom\n" if $debug;    } else {        printf STDERR "Unrecognized command '$tokens[0]' in $id\n";        $errors_found++;        return;    }}