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Viewing changes to dttools/src/process.c

  • Committer: Bazaar Package Importer
  • Author(s): Michael Hanke
  • Date: 2011-05-07 09:05:00 UTC
  • Revision ID: james.westby@ubuntu.com-20110507090500-lqpmdtwndor6e7os
Tags: upstream-3.3.2
Import upstream version 3.3.2

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dttools/src/process.c
 
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/*
 
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Copyright (C) 2008- The University of Notre Dame
 
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This software is distributed under the GNU General Public License.
 
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See the file COPYING for details.
 
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*/
 
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#include "process.h"
 
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#include "list.h"
 
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#include <sys/wait.h>
 
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#include <unistd.h>
 
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#include <stdlib.h>
 
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#include <signal.h>
 
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static struct list * complete_list = 0;
 
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static void alarm_handler( int sig )
 
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{
 
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        // do nothing except interrupt the wait
 
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}
 
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static int process_work( int timeout )
 
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{
 
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        void *old_handler = 0;
 
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        int flags = 0;
 
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        if(timeout==0) {
 
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                flags = WNOHANG;
 
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        } else {
 
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                flags = 0;
 
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                old_handler = signal(SIGALRM,alarm_handler);
 
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                alarm(timeout);
 
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        }
 
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        struct process_info p;
 
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        p.pid = wait4(-1,&p.status,flags,&p.rusage);
 
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        if(p.pid<=0) return 0;
 
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        struct process_info *i = malloc(sizeof(*i));
 
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        *i = p;
 
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        list_push_tail(complete_list,i);
 
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        return 1;
 
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}
 
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struct process_info * process_wait( int timeout )
 
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{
 
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        struct process_info *p;
 
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        if(!complete_list) complete_list = list_create();
 
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        p = list_pop_head(complete_list);
 
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        if(p) return p;
 
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        process_work(timeout);
 
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        return list_pop_head(complete_list);
 
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}
 
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void process_putback( struct process_info *p )
 
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{
 
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        if(!complete_list) complete_list = list_create();
 
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        list_push_tail(complete_list,p);        
 
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}
 
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int process_pending()
 
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{
 
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        if(!complete_list) complete_list = list_create();
 
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        if(list_size(complete_list)>0) return 1;
 
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        return process_work(0);
 
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}