src/tests/read-vs-mmap2.c

   1 /*
   2  * Copyright (c) 1995 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include <config.h>
  36 #endif
  37
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <sys/types.h>
  41 #include <fcntl.h>
  42 #include <time.h>
  43 #include <unistd.h>
  44 #include <string.h>
  45 #include <sys/mman.h>
  46 #include <sys/stat.h>
  47 #include <err.h>
  48
  49 static void
  50 generate_random_file(const char *filename, size_t sz)
  51 {
  52     int fd;
  53     char *buf;
  54     int i;
  55
  56     buf = malloc(sz);
  57     if (buf == NULL)
  58         err(1, "malloc %u", (unsigned)sz);
  59
  60     fd = open(filename, O_WRONLY | O_CREAT, 0666);
  61     if (fd < 0)
  62         err(1, "open %s", filename);
  63
  64     for (i = 0; i < sz; ++i)
  65         buf[i] = rand();
  66
  67     if (write(fd, buf, sz) != sz)
  68         err(1, "write");
  69     if (close(fd))
  70         err(1, "close");
  71     free(buf);
  72 }
  73
  74 static char *
  75 read_file(int fd, size_t sz)
  76 {
  77     char *buf;
  78     ssize_t ret;
  79
  80     buf = malloc(sz);
  81     if (buf == NULL)
  82         err(1, "malloc %u", (unsigned)sz);
  83     ret = read(fd, buf, sz);
  84     if (ret < 0)
  85         err(1, "read");
  86     if (ret != sz)
  87         errx(1, "short read %d < %u", (int)ret, (unsigned)sz);
  88     return buf;
  89 }
  90
  91 #ifndef MAP_FAILED
  92 #define MAP_FAILED ((void *)-1)
  93 #endif
  94
  95 static void *
  96 mmap_file(int fd, size_t sz)
  97 {
  98     void *ret;
  99
 100     ret = mmap(0, sz, PROT_READ, MAP_SHARED, fd, 0);
 101     if (ret == (void *)MAP_FAILED)
 102         err(1, "mmap");
 103     return ret;
 104 }
 105
 106 int
 107 main(int argc, char **argv)
 108 {
 109     const char *file = "foo";
 110     const size_t sz = 16384;
 111     char *malloc_buf;
 112     void *mmap_buf;
 113     int fd;
 114
 115     srand(time(NULL));
 116
 117     generate_random_file(file, sz);
 118
 119     fd = open(file, O_RDONLY, 0);
 120     if (fd < 0)
 121         err(1, "open %s", file);
 122
 123     malloc_buf = read_file(fd, sz);
 124     mmap_buf = mmap_file(fd, sz);
 125     close(fd);
 126     unlink(file);
 127     if (memcmp(malloc_buf, mmap_buf, sz) != 0)
 128         return 1;
 129     return 0;
 130 }