mirror of
https://github.com/jart/cosmopolitan.git
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72 lines
3.5 KiB
C
72 lines
3.5 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/atomic.h"
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#include "libc/calls/calls.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/futex.h"
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#include "libc/sysv/consts/nr.h"
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#include "libc/thread/thread.h"
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/**
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* Waits for thread to terminate and frees its memory.
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*
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* @param td is thread descriptor memory
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* @param exitcode optionally receives value returned by thread
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* @return 0 on success, or error number on failure
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* @raises EDEADLK when trying to join this thread
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* @raises EINVAL if another thread is joining
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* @raises ESRCH if no such thread exists
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* @raises EINVAL if not joinable
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* @threadsafe
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*/
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int cthread_join(cthread_t td, void **exitcode) {
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int x, rc, tid;
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// otherwise, tid could be set to 0 even though `state` is not
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// finished mark thread as joining
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if (!td || (IsAsan() && !__asan_is_valid(td, sizeof(*td)))) {
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rc = ESRCH;
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tid = -1;
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} else if ((tid = td->tid) == gettid()) { // tid must load before lock xadd
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rc = EDEADLK;
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} else if (atomic_load(&td->state) & (cthread_detached | cthread_joining)) {
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rc = EINVAL;
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} else {
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if (~atomic_fetch_add(&td->state, cthread_joining) & cthread_finished) {
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while ((x = atomic_load(&td->tid))) {
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cthread_memory_wait32(&td->tid, x, 0);
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}
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}
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if (exitcode) {
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*exitcode = td->exitcode;
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}
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if (!munmap(td->alloc.bottom, td->alloc.top - td->alloc.bottom)) {
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rc = 0;
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} else {
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rc = errno;
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}
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}
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STRACE("cthread_join(%d, [%p]) → %s", tid, !rc && exitcode ? *exitcode : 0,
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!rc ? "0" : strerrno(rc));
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return rc;
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}
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