mirror of
https://github.com/jart/cosmopolitan.git
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3f0bcdc3ef
- Exhaustively document cancellation points - Rename SIGCANCEL to SIGTHR just like BSDs - Further improve POSIX thread cancellations - Ensure asynchronous cancellations work correctly - Elevate the quality of getrandom() and getentropy() - Make futexes cancel correctly on OpenBSD 6.x and 7.x - Add reboot.com and shutdown.com to examples directory - Remove underscore prefix from awesome timespec_*() APIs - Create assertions that help verify our cancellation points - Remove bad timespec APIs (cmp generalizes eq/ne/gt/gte/lt/lte)
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/calls/calls.h"
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#include "libc/calls/cp.internal.h"
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#include "libc/calls/syscall_support-nt.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sock/internal.h"
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/**
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* Waits for signal.
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*
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* This suspends execution until an unmasked signal is delivered. If the
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* signal delivery kills the process, this won't return. The signal mask
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* of the current thread is used. If a signal handler exists, this shall
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* return after it's been invoked.
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*
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* This function is equivalent to:
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*
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* select(0, 0, 0, 0, 0);
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*
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* However this has a tinier footprint and better logging.
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*
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* @return -1 w/ errno set to EINTR
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* @cancellationpoint
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* @see sigsuspend()
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* @norestart
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*/
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int pause(void) {
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int rc;
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STRACE("pause() → [...]");
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BEGIN_CANCELLATION_POINT;
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if (!IsWindows()) {
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// We'll polyfill pause() using select() with a null timeout, which
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// should hopefully do the same thing, which means wait forever but
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// the usual signal interrupt rules apply.
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//
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// "If the readfds, writefds, and errorfds arguments are all null
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// pointers and the timeout argument is not a null pointer, the
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// pselect() or select() function shall block for the time
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// specified, or until interrupted by a signal. If the readfds,
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// writefds, and errorfds arguments are all null pointers and the
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// timeout argument is a null pointer, the pselect() or select()
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// function shall block until interrupted by a signal." ──Quoth
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// IEEE 1003.1-2017 §functions/select
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//
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rc = sys_select(0, 0, 0, 0, 0);
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} else {
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rc = sys_pause_nt();
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}
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END_CANCELLATION_POINT;
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STRACE("[...] pause → %d% m", rc);
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return rc;
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}
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