code.delx.au - pulseaudio/blob - src/polypcore/random.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation; either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28 #include <errno.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <assert.h>
  32 #include <time.h>
  33
  34 #include <polypcore/util.h>
  35 #include <polypcore/log.h>
  36
  37 #include "random.h"
  38
  39 #ifndef OS_IS_WIN32
  40 #define RANDOM_DEVICE "/dev/urandom"
  41 #endif
  42
  43 void pa_random(void *ret_data, size_t length) {
  44     int fd;
  45     ssize_t r = 0;
  46     assert(ret_data && length);
  47
  48 #ifdef RANDOM_DEVICE
  49     if ((fd = open(RANDOM_DEVICE, O_RDONLY)) >= 0) {
  50
  51         if ((r = pa_loop_read(fd, ret_data, length)) < 0 || (size_t) r != length)
  52             pa_log_error(__FILE__": failed to read entropy from '%s'\n", RANDOM_DEVICE);
  53
  54         close(fd);
  55     }
  56 #endif
  57
  58     if ((size_t) r != length) {
  59         uint8_t *p;
  60         size_t l;
  61
  62 #ifdef RANDOM_DEVICE
  63         pa_log_warn(__FILE__": WARNING: Failed to open entropy device '"RANDOM_DEVICE"': %s"
  64                     ", falling back to unsecure pseudo RNG.\n", strerror(errno));
  65 #endif
  66
  67         srand(time(NULL));
  68
  69         for (p = ret_data, l = length; l > 0; p++, l--)
  70             *p = (uint8_t) rand();
  71     }
  72 }