/**

 * mem2swap.c

 * Copyright (C) 2008 Markus Broeker

 *

 * mem2swap usage: mem2swap [<MB>]

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <errno.h>

#include <sys/wait.h>

#define N 1000

#ifndef DEFAULT_MEGS

#define DEFAULT_MEGS 64

#endif

#ifdef __linux__

#define CMD_FREE "/usr/bin/free"

#define CMD_ARGS "-m"

#elif __unix__

#define CMD_FREE "/sbin/sysctl"

#define CMD_ARGS "hw.usermem"

#else

#define CMD_FREE "/sbin/sysctl"

#define CMD_ARGS "hw.usermem"

#endif

int set_limit (int);

int main (int argc, char **argv)

{

    int i, n = 0;

    unsigned long *p;

    unsigned long *p_new;

    char *args[] = { CMD_FREE, CMD_ARGS, NULL };

    unsigned long size = sizeof (*p);

    int megs = DEFAULT_MEGS;

    int pid;

    if (argc == 2)

        megs = atoi (argv[1]);

    printf ("Mem2Swap - Version 1.0\n");

    if (!set_limit (megs))

        printf ("%d MB demanded ", megs);

    else {

        printf ("\tUsage: %s [MEM]\n\n", argv[0]);

        printf ("Report bugs to mbroeker@largo.homelinux.org\n");

        perror ("Limit Error");

        return EXIT_FAILURE;

    }

    if ((p = malloc (N * size)) == NULL)

        return EXIT_FAILURE;

    for (;;) {

        for (i = 0; i < N; i++)

            p[n * N + i] = size * (n * N + i);

        if ((p_new = realloc (p, (++n + 1) * N * size)))

            p = p_new;

        else

            break;

    }

    if (p) {

        printf ("and %ld MB allocated\n", p[n * N - 1] / 1024 / 1024);

        free (p);

    }

    printf ("\n\n");

    pid = fork ();

    switch (pid) {

    case 0:

        execve (CMD_FREE, args, NULL);

        exit (EXIT_FAILURE);

    case -1:

        perror ("Fork Error");

        return EXIT_FAILURE;

    default:

        wait (&pid);

    }

    return pid;

}