/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or distribute this software for         │
│ any purpose with or without fee is hereby granted, provided that the         │
│ above copyright notice and this permission notice appear in all copies.      │
│                                                                              │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
│ PERFORMANCE OF THIS SOFTWARE.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/sched-sysv.internal.h"
#include "libc/calls/struct/cpuset.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"
#include "libc/thread/posixthread.internal.h"

/**
 * Gets CPU affinity for thread.
 *
 * @param size is bytes in bitset, which should be `sizeof(cpu_set_t)`
 * @return 0 on success, or errno on error
 * @raise EINVAL if `size` or `bitset` is invalid
 * @raise ENOSYS if not Linux, FreeBSD, or NetBSD
 * @raise ESRCH if thread isn't alive
 */
errno_t pthread_getaffinity_np(pthread_t thread, size_t size,
                               cpu_set_t *bitset) {
  int e, rc, tid;

  if (!(rc = pthread_getunique_np(thread, &tid))) {
    e = errno;
    if (size != sizeof(cpu_set_t)) {
      rc = einval();
    } else if (IsWindows() || IsMetal() || IsOpenbsd()) {
      rc = enosys();
    } else if (IsFreebsd()) {
      if (!sys_sched_getaffinity_freebsd(CPU_LEVEL_WHICH, CPU_WHICH_TID, tid,
                                         32, bitset)) {
        rc = 32;
      } else {
        rc = -1;
      }
    } else if (IsNetbsd()) {
      if (!sys_sched_getaffinity_netbsd(tid, 0, 32, bitset)) {
        rc = 32;
      } else {
        rc = -1;
      }
    } else {
      rc = sys_sched_getaffinity(tid, size, bitset);
    }
    if (rc > 0) {
      if (rc < size) {
        bzero((char *)bitset + rc, size - rc);
      }
      rc = 0;
    }
  }

  STRACE("pthread_getaffinity_np(%d, %'zu, %p) → %s", tid, size, bitset,
         DescribeErrno(rc));
  return rc;
}