libc/inet/rpc/create_xid.c

   1 /* Copyright (c) 1998, 2000 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Thorsten Kukuk <kukuk@vt.uni-paderborn.de>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <unistd.h>
  20 #include <stdlib.h>
  21 #include <sys/time.h>
  22 #include "rpc_private.h"
  23
  24
  25 /* The RPC code is not threadsafe, but new code should be threadsafe. */
  26
  27 #include <bits/uClibc_mutex.h>
  28 __UCLIBC_MUTEX_STATIC(mylock, PTHREAD_MUTEX_INITIALIZER);
  29
  30 static smallint is_initialized;
  31 static struct drand48_data __rpc_lrand48_data;
  32
  33 u_long _create_xid (void)
  34 {
  35   long res;
  36
  37   __UCLIBC_MUTEX_LOCK(mylock);
  38
  39   if (!is_initialized)
  40     {
  41       struct timeval now;
  42
  43       gettimeofday (&now, (struct timezone *) 0);
  44       srand48_r (now.tv_sec ^ now.tv_usec, &__rpc_lrand48_data);
  45       is_initialized = 1;
  46     }
  47
  48   lrand48_r (&__rpc_lrand48_data, &res);
  49
  50   __UCLIBC_MUTEX_UNLOCK(mylock);
  51
  52   return res;
  53 }