tests/genrandom.c

   1 /*
   2  * Copyright (c) 2001, 2006-2007 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 <roken.h>
  39 #include <err.h>
  40
  41 RCSID("$Id$");
  42
  43 #define BUF_SIZE        (128*1024)
  44
  45 /*
  46  * Silly "random" data generator, writes `nbytes' to stdout, from
  47  * `offset' in our stream.
  48  */
  49
  50 static void *
  51 fill_buf(unsigned long *buf, unsigned long long base)
  52 {
  53     unsigned i;
  54
  55     if (!buf) {
  56         buf = malloc(BUF_SIZE);
  57
  58         if (!buf)
  59             errx(1, "malloc failed");
  60     }
  61
  62     srandom(base / BUF_SIZE);
  63     for (i = 0; i < BUF_SIZE/sizeof(long); i++) {
  64         unsigned long tmp = random();
  65         buf[i] = tmp ^ (tmp << 1);
  66     }
  67     return buf;
  68 }
  69
  70 static void
  71 doit(long long offset, long long nbytes)
  72 {
  73     unsigned long long base, off;
  74     char *buf = NULL;
  75     size_t sz;
  76     int ret;
  77
  78     while (nbytes) {
  79         base = offset & (~(BUF_SIZE - 1));
  80         off = offset - base;
  81         if (base == offset || !buf)
  82             buf = fill_buf((void *)buf, base);
  83
  84         sz = BUF_SIZE - off;
  85         if (sz > nbytes)
  86             sz = nbytes;
  87         ret = write(STDOUT_FILENO, buf + off, sz);
  88         if (ret != sz)
  89             err(1, "write at %llu", (unsigned long long)offset);
  90         offset += ret;
  91         nbytes -= ret;
  92     }
  93
  94     free(buf);
  95 }
  96
  97 int
  98 main(int argc, char **argv)
  99 {
 100     long long nbytes, offset = 0;
 101
 102     setprogname(argv[0]);
 103
 104     if (argc < 2 || argc > 3)
 105         errx(1, "usage: %s nbytes [offset]", argv[0]);
 106
 107     nbytes = strtoll(argv[1], NULL, 10); /* XXX errno */
 108
 109     if (argc == 3)
 110         offset = strtoll(argv[2], NULL, 10); /* XXX errno */
 111
 112     doit(offset, nbytes);
 113
 114     return 0;
 115 }