sched_setaffinity.c 2.2 KB

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  1. /* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, see
  13. <http://www.gnu.org/licenses/>. */
  14. #include <sys/syscall.h>
  15. #if defined __NR_sched_setaffinity && defined __USE_GNU
  16. # include <sched.h>
  17. # include <sys/types.h>
  18. # include <string.h>
  19. # include <unistd.h>
  20. # include <alloca.h>
  21. # define __NR___syscall_sched_setaffinity __NR_sched_setaffinity
  22. static __always_inline _syscall3(int, __syscall_sched_setaffinity, __kernel_pid_t, pid,
  23. size_t, cpusetsize, const cpu_set_t *, cpuset)
  24. static size_t __kernel_cpumask_size;
  25. int sched_setaffinity(pid_t pid, size_t cpusetsize, const cpu_set_t *cpuset)
  26. {
  27. size_t cnt;
  28. int res;
  29. size_t psize = 128;
  30. void *p = alloca (psize);
  31. if (unlikely (__kernel_cpumask_size == 0)) {
  32. INTERNAL_SYSCALL_DECL (err);
  33. while (res = INTERNAL_SYSCALL (sched_getaffinity, err, 3, getpid (),
  34. psize, p),
  35. INTERNAL_SYSCALL_ERROR_P (res, err)
  36. && INTERNAL_SYSCALL_ERRNO (res, err) == EINVAL)
  37. p = extend_alloca (p, psize, 2 * psize);
  38. if (res == 0 || INTERNAL_SYSCALL_ERROR_P (res, err)) {
  39. __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
  40. return -1;
  41. }
  42. __kernel_cpumask_size = res;
  43. }
  44. /* We now know the size of the kernel cpumask_t. Make sure the user
  45. does not request to set a bit beyond that. */
  46. for (cnt = __kernel_cpumask_size; cnt < cpusetsize; ++cnt)
  47. if (((char *) cpuset)[cnt] != '\0') {
  48. /* Found a nonzero byte. This means the user request cannot be
  49. fulfilled. */
  50. __set_errno (EINVAL);
  51. return -1;
  52. }
  53. return __syscall_sched_setaffinity(pid, cpusetsize, cpuset);
  54. }
  55. #endif