mirror of
https://github.com/jart/cosmopolitan.git
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53 lines
2.9 KiB
C
53 lines
2.9 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/runtime/runtime.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/descriptor.h"
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#include "libc/thread/join.h"
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int cthread_join(cthread_t td, int* rc) {
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int tid = td->tid; // tid must be loaded before lock xadd
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// otherwise, tid could be set to 0 even though `state` is not finished
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// mark thread as joining
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int state;
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asm volatile("lock xadd\t%1, %0"
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: "+m"(td->state), "=r"(state)
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: "1"(cthread_joining)
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: "cc");
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if (!(state & cthread_finished)) {
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int ax;
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int flags = FUTEX_WAIT; // PRIVATE makes it hang
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struct timespec* timeout = NULL;
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asm volatile("mov\t%5,%%r10\n\t" // timeout
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"syscall"
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: "=a"(ax)
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: "0"(__NR_futex), "D"(&td->tid), "S"(flags), "d"(tid),
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"g"(timeout)
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: "rcx", "r10", "r11", "cc", "memory");
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}
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*rc = td->rc;
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size_t size = (intptr_t)(td->alloc.top) - (intptr_t)(td->alloc.bottom);
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munmap(td->alloc.bottom, size);
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return 0;
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}
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