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/*
* This file has been modified for the cdrkit suite.
*
* The behaviour and appearence of the program code below can differ to a major
* extent from the version distributed by the original author(s).
*
* For details, see Changelog file distributed with the cdrkit package. If you
* received this file from another source then ask the distributing person for
* a log of modifications.
*
*/
#ident "$Id: workers.c,v 1.3 2006/07/04 04:57:42 hpa Exp $"
/* ----------------------------------------------------------------------- *
*
* Copyright 2001-2006 H. Peter Anvin - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
* USA; either version 2 of the License, or (at your option) any later
* version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* workers.c
*
* Parallel job maintenance
*/
#include "mkzftree.h" /* Must be included first! */
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <sys/wait.h>
/* Global option */
extern int parallel; /* Number of parallel jobs */
/* Functions related to parallel execution */
static volatile int work_threads = 0;
static int is_worker = 0;
/* This waits for one worker to finish */
static void wait_for_one_worker(void)
{
int status;
if ( wait(&status) > 0 ) {
work_threads--;
if ( WIFSIGNALED(status) ) {
kill(getpid(), WTERMSIG(status));
exit(EX_SOFTWARE);
} else if ( WEXITSTATUS(status) ) {
exit(WEXITSTATUS(status));
}
}
}
/* This waits for *all* workers to finish */
void wait_for_all_workers(void)
{
while ( work_threads )
wait_for_one_worker();
}
/* This returns 1 if the "job" at hand should be performed */
int spawn_worker(void)
{
pid_t f;
if ( opt.parallel == 0 )
return 1;
fflush(NULL);
/* Wait for a work slot */
while ( work_threads >= opt.parallel )
wait_for_one_worker();
/* Spawn worker process */
work_threads++; /* Avoids race conditions */
f = fork();
if ( f == -1 ) {
work_threads--;
return 1; /* Do it ourselves */
}
if ( f == 0 ) {
/* Worker process */
is_worker = 1;
return 1;
} else {
/* Control process */
return 0;
}
}
/* Routine to perform at the end of the job */
void end_worker(int err)
{
if ( is_worker ) {
exit(err);
}
}
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