backoff.c

distcc编译器的源代码.好像是readhat公司开发的.

/* -*- c-file-style: "java"; indent-tabs-mode: nil; fill-column: 78 -*-
 * 
 * distcc -- A simple distributed compiler system
 *
 * Copyright (C) 2002, 2003 by Martin Pool <[e-mail]>
 *
 * 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; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 */


/**
 * @file
 *
 * Keep track of hosts which are, or are not, usable.
 **/

#include "config.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <time.h>

#include <sys/stat.h>
#include <sys/file.h>

#include "distcc.h"
#include "trace.h"
#include "util.h"
#include "exitcode.h"
#include "snprintf.h"
#include "lock.h"
#include "timefile.h"
#include "hosts.h"


const int dcc_backoff_period = 60; /* seconds */


/**
 * Remember that this host is working OK.
 *
 * For the moment this just means removing any backoff timer scored against
 * it.
 **/
int dcc_enjoyed_host(const struct dcc_hostdef *host)
{
    return dcc_remove_timefile("backoff", host);
}

int dcc_disliked_host(const struct dcc_hostdef *host)
{
    /* i hate you (but only for 60 seconds) */
    return dcc_mark_timefile("backoff", host);
}


static int dcc_check_backoff(struct dcc_hostdef *host)
{
    int ret;
    time_t mtime;

    if ((ret = dcc_check_timefile("backoff", host, &mtime)))
        return ret;

    if (difftime(time(NULL), mtime) < (double) dcc_backoff_period) {
        rs_trace("still in backoff period for %s", host->hostdef_string);
        return EXIT_BUSY;
    }

    return 0;
}


/**
 * Walk through @p hostlist and remove any hosts that are marked unavailable.
 **/
int dcc_remove_disliked(struct dcc_hostdef **hostlist)
{
    struct dcc_hostdef *h;
    
    while ((h = *hostlist) != NULL) {
        if (dcc_check_backoff(h) != 0) {
            rs_trace("remove %s from list", h->hostdef_string);
            *hostlist = h->next;
            free(h);
        } else {
            /* check next one */
            hostlist = &h->next;
        }
    }
    
    return 0;
}