create_xid.c 1.8 KB

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  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. The GNU C Library is free software; you can redistribute it and/or
  5. modify it under the terms of the GNU Lesser General Public
  6. License as published by the Free Software Foundation; either
  7. version 2.1 of the License, or (at your option) any later version.
  8. The GNU C Library is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. Lesser General Public License for more details.
  12. You should have received a copy of the GNU Lesser General Public
  13. License along with the GNU C Library; if not, write to the Free
  14. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  15. 02111-1307 USA. */
  16. #define __FORCE_GLIBC
  17. #include <features.h>
  18. #include <unistd.h>
  19. #include <stdlib.h>
  20. #include <sys/time.h>
  21. #include <rpc/rpc.h>
  22. /* The RPC code is not threadsafe, but new code should be threadsafe. */
  23. #ifdef __UCLIBC_HAS_THREADS__
  24. #include <pthread.h>
  25. static pthread_mutex_t createxid_lock = PTHREAD_MUTEX_INITIALIZER;
  26. # define LOCK __pthread_mutex_lock(&createxid_lock)
  27. # define UNLOCK __pthread_mutex_unlock(&createxid_lock);
  28. #else
  29. # define LOCK
  30. # define UNLOCK
  31. #endif
  32. static int is_initialized;
  33. static struct drand48_data __rpc_lrand48_data;
  34. unsigned long
  35. _create_xid (void)
  36. {
  37. unsigned long res;
  38. LOCK;
  39. if (!is_initialized)
  40. {
  41. struct timeval now;
  42. gettimeofday (&now, (struct timezone *) 0);
  43. srand48_r (now.tv_sec ^ now.tv_usec, &__rpc_lrand48_data);
  44. is_initialized = 1;
  45. }
  46. lrand48_r (&__rpc_lrand48_data, &res);
  47. UNLOCK;
  48. return res;
  49. }