busybox/util-linux/swaponoff.c

/*
 * Mini swapon/swapoff implementation for busybox
 *
 * Copyright (C) 1998 by Erik Andersen <andersee@debian.org>
 *
 * 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
 *
 */

#include "internal.h"
#include <stdio.h>
#include <sys/mount.h>
#include <sys/swap.h>
#include <mntent.h>
#include <dirent.h>
#include <fstab.h>
#include <errno.h>


static int whichApp;
static const char* appName;

static const char swapoff_usage[] = 
"swapoff device\n"
"\nStop swapping virtual memory pages on the given device.\n";
static const char swapon_usage[] = 
"swapon device\n"
"\nStart swapping virtual memory pages on the given device.\n";


#define SWAPON_APP   1
#define SWAPOFF_APP  2


static void
swap_enable_disable( char *device)
{
    int status;
    if ( whichApp == SWAPON_APP )
	status = swapon(device, 0);
    else 
	status = swapoff(device);

    if ( status != 0 ) { 
	perror(appName);
	exit( FALSE);
    }
}

static void
do_em_all()
{
	struct mntent *m;
	char swapName[NAME_MAX];
	FILE *f = setmntent ("/etc/fstab", "r");

	if (f == NULL) {
	    perror("/etc/fstab");
	    exit( FALSE); 
	}
	while ((m = getmntent (f)) != NULL) {
	    if (!strstr (m->mnt_type, "swap")) {
		    swap_enable_disable( swapName);
	    }
	}
	endmntent (f);
	exit( TRUE);
}


extern int
swap_on_off_main(int argc, char * * argv)
{
    struct stat statBuf;
    if (stat("/etc/fstab", &statBuf) < 0) 
	fprintf(stderr, "/etc/fstab file missing -- Please install one.\n\n");

    if (strcmp(*argv, "swapon")==0) {
	appName = *argv;
	whichApp = SWAPON_APP;

    } else {
	appName = *argv;
	whichApp = SWAPOFF_APP;
    }

    if (argc < 2)
	goto usage_and_exit;
    argc--;
    argv++;

    /* Parse any options */
    while (**argv == '-') {
	while (*++(*argv)) switch (**argv) {
	    case 'a':
		do_em_all();
		break;
	    default:
		goto usage_and_exit;
	}
    }
    swap_enable_disable(*argv);
    exit( TRUE);

usage_and_exit:
    usage( (whichApp==SWAPON_APP)? swapon_usage : swapoff_usage);
    exit( FALSE);
}