src/tests/write-rand.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 char *
  50 write_random_file(int fd, size_t sz)
  51 {
  52     char *buf;
  53     int i, j;
  54
  55     j = sz;
  56     if (j > 2048) {
  57         j = 2048;
  58     }
  59     buf = malloc(j);
  60     if (buf == NULL)
  61         err(1, "malloc %u", (unsigned)sz);
  62
  63     for (i = 0; i < j; ++i) {
  64         buf[i] = rand();
  65     }
  66     while (sz > 0) {
  67         if (write(fd, buf, j) != j)
  68             err(1, "write");
  69
  70         sz -= j;
  71         j = sz;
  72         if (j > 2048)
  73             j = 2048;
  74     }
  75
  76     return 0;
  77 }
  78
  79 int
  80 main(int argc, char **argv)
  81 {
  82     const char *file;
  83     size_t sz;
  84     int fd;
  85
  86     if (argc != 3)
  87         errx(1, "usage: %s file size", argv[0]);
  88
  89     file = argv[1];
  90     sz = atoi(argv[2]);
  91
  92     srand(time(NULL));
  93
  94     fd = open(file, O_RDWR | O_CREAT, 0755);
  95     if (fd < 0)
  96         err(1, "open %s", file);
  97
  98     if (lseek(fd, 0, SEEK_SET) < 0)
  99         err(1, "lseek");
 100     write_random_file(fd, sz);
 101
 102     close(fd);
 103     return 0;
 104 }