/*
 * Copyright (c) 1995 - 2001 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <fcntl.h>
#include <time.h>
#include <unistd.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <err.h>

#ifdef RCSID
RCSID("$Id: mmap-vs-read.c,v 1.2 2003/07/15 23:17:01 shadow Exp $");
#endif

static int debug = 0;

static void
generate_file(const char *filename, int randomp, size_t sz)
{
    int fd;
    char *buf;
    int i;

    buf = malloc(sz);
    if (buf == NULL)
	err(1, "malloc %u", (unsigned)sz);

    fd = open(filename, O_WRONLY | O_CREAT, 0666);
    if (fd < 0)
	err(1, "open %s", filename);

    for (i = 0; i < sz; ++i)
	if (randomp)
	    buf[i] = rand();
	else
	    buf[0] = 0;

    if (write(fd, buf, sz) != sz)
	err(1, "write");
    if (close(fd))
	err(1, "close");
    free(buf);
}

static char *
read_file(int fd, size_t sz)
{
    char *buf;
    ssize_t ret;

    buf = malloc(sz);
    if (buf == NULL)
	err(1, "malloc %u", (unsigned)sz);
    ret = read(fd, buf, sz);
    if (ret < 0)
	err(1, "read");
    if (ret != sz)
	errx(1, "short read %d < %u", (int)ret, (unsigned)sz);
    return buf;
}

#ifndef MAP_FAILED
#define MAP_FAILED ((void *)-1)
#endif

static void *
mmap_file(int fd, size_t sz)
{
    void *ret;

    ret = mmap(0, sz, PROT_READ, MAP_SHARED, fd, 0);
    if (ret == (void *)MAP_FAILED)
	err(1, "mmap");
    return ret;
}

static void __attribute__ ((__unused__))
    print_area(unsigned char *ptr, size_t len)
{
    while (len--) {
	printf("%x", *ptr);
	ptr++;
    }
}

static int
do_test(int randomp)
{
    unsigned char *malloc_buf;
    void *mmap_buf;
    int fd;
    const char *file = "foo";
    const size_t sz = 4 * getpagesize();

    generate_file(file, randomp, sz);

    fd = open(file, O_RDONLY, 0);
    if (fd < 0)
	err(1, "open %s", file);

    mmap_buf = mmap_file(fd, sz);
    malloc_buf = read_file(fd, sz);
    close(fd);
    unlink(file);
    if (memcmp(malloc_buf, mmap_buf, sz) != 0) {
	if (debug) {
	    printf("type: %s\n", randomp ? "random" : "allzero");
	    printf("read: ");
	    print_area(malloc_buf, sz);
	    printf("\nmmap: ");
	    print_area(mmap_buf, sz);
	    printf("\n");
	}
	return 1;
    }
    return 0;
}

int
main(int argc, char **argv)
{

    if (argc != 1)
	debug = 1;

    srand(time(NULL));

    if (do_test(0))
	return 1;
    if (do_test(1))
	return 2;

    return 0;
}
