/*-*- 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 2020 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/bits/atomic.h"
#include "libc/calls/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/errno.h"
#include "libc/intrin/asan.internal.h"
#include "libc/str/str.h"
#include "libc/thread/thread.h"

/**
 * Detaches thread.
 *
 * Calling this function will cause the thread to free its own memory
 * once it exits. Using this function is mutually exclusive from the
 * chtread_join() API.
 *
 * @return 0 on success or errno number on failure
 * @raises EINVAL if thread isn't joinable
 * @raises ESRCH if no such thread exists
 * @threadsafe
 */
int cthread_detach(cthread_t td) {
  int rc, tid;
  if (!td || (IsAsan() && !__asan_is_valid(td, sizeof(*td)))) {
    rc = ESRCH;
    tid = -1;
  } else if ((tid = td->tid) == gettid()) {
    rc = EDEADLK;
  } else if (atomic_load(&td->state) & (cthread_detached | cthread_joining)) {
    rc = EINVAL;
  } else if (!atomic_fetch_add(&td->state, cthread_detached) &
             cthread_finished) {
    rc = 0;
  } else if (!munmap(td->alloc.bottom, td->alloc.top - td->alloc.bottom)) {
    rc = 0;
  } else {
    rc = errno;
  }
  STRACE("cthread_detached(%d) → %s", tid, !rc ? "0" : strerrno(rc));
  return rc;
}