randomness.c++

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/*
 *randomness.h++ platform-specific random number generator stuff.  Should mostly be used for seeding
    the GSL random number generator.

    Copyright (C) 2010 Joseph Pingenot

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include <stdio.h>
#include <glib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <libmodelxx/randomness.h++>
#include <config.h>

#define RANDOMNESS_GERROR_DOMAIN 15

namespace kdotp {
  namespace libmodelxx {
    namespace randomness {


      unsigned long int get_random_unsigned_long_int(GError **err) {
  #if HOST_OS != LINUX
  #error This currently only supports Linux.
  #else
  long unsigned rnum;
  int fd = open("/dev/random", O_RDONLY);
  if(fd == -1) {
    *err = g_error_new(RANDOMNESS_GERROR_DOMAIN, 1, "libmodelxx::randomness::randomness.c++::get_random_unsinged_long_int: Error while opening /proc/random: %d (%s)\n", errno, strerror(errno));
    return 0;
  }
  ssize_t len = read(fd, &rnum, sizeof(unsigned long int));
  if(len != sizeof(unsigned long int)) {
    *err = g_error_new(RANDOMNESS_GERROR_DOMAIN, 1, "libmodelxx::randomness::randomness.c++::get_random_unsinged_long_int: Failed to read an entire unsigned long int: %d (%s)\n", errno, strerror(errno));
    close(fd);
    return 0;
  }
  close(fd);
  fprintf(stderr, "get_urandom_unsinged_long_int: returning %lu\n", rnum);
  return rnum;
  #endif
      }

      /**Will get from /dev/urandom if present.  Otherwise, is identical to random.*/
      unsigned long int get_urandom_unsigned_long_int(GError **err) {
  #if HOST_OS != LINUX
  return get_random_unsigned_long_int(err);
  #else
  long unsigned rnum;
  int fd = open("/dev/urandom", O_RDONLY);
  if(fd == -1) {
    *err = g_error_new(RANDOMNESS_GERROR_DOMAIN, 1, "libmodelxx::randomness::randomness.c++::get_urandom_unsinged_long_int: Error while opening /proc/urandom: %d (%s)\n", errno, strerror(errno));
    return 0;
  }
  ssize_t len = read(fd, &rnum, sizeof(unsigned long int));
  if(len != sizeof(unsigned long int)) {
    *err = g_error_new(RANDOMNESS_GERROR_DOMAIN, 1, "libmodelxx::randomness::randomness.c++::get_urandom_unsinged_long_int: Failed to read an entire unsigned long int: %d (%s)\n", errno, strerror(errno));
    close(fd);
    return 0;
  }
  close(fd);
  fprintf(stderr, "get_urandom_unsinged_long_int: returning %lu\n", rnum);
  return rnum;
        #endif
      }


    }
  }
}