/*      $OpenBSD: minherit.c,v 1.3 2003/08/02 01:24:36 david Exp $      */
/*
 * Written by Artur Grabowski <art@openbsd.org> Public Domain.
 */
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/mman.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>
#include <unistd.h>

#define MAGIC "inherited"

int
main(int argc, char *argv[])
{
        void *map1, *map2;
        int page_size;
        int status;

        page_size = getpagesize();

        if ((map1 = mmap(NULL, page_size, PROT_READ|PROT_WRITE, MAP_ANON,
            -1, 0)) == MAP_FAILED)
                err(1, "mmap");

        if ((map2 = mmap(NULL, page_size, PROT_READ|PROT_WRITE, MAP_ANON,
            -1, 0)) == MAP_FAILED)
                err(1, "mmap");

        memset(map1, 0, sizeof(MAGIC));
        memcpy(map2, MAGIC, sizeof(MAGIC));

        if (minherit(map1, page_size, MAP_INHERIT_SHARE) != 0)
                err(1, "minherit");

        if (minherit(map2, page_size, MAP_INHERIT_NONE) != 0)
                err(1, "minherit");

        switch(fork()) {
        case -1:
                err(1, "fork");
        case 0:
                memcpy(map1, MAGIC, sizeof(MAGIC));
                /* map2 is not mapped and should give us error on munmap */
                if (munmap(map2, page_size) == 0)
                        _exit(1);
                _exit(0);
        }

        if (wait(&status) < 0)
                err(1, "wait");

        if (!WIFEXITED(status))
                err(1, "child error");

        if (memcmp(map1, MAGIC, sizeof(MAGIC)) != 0)
                return 1;

        return WEXITSTATUS(status) != 0;
}