mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 15:03:34 +00:00
dd8c4dbd7d
There's now a much stronger level of assurance that signaling on Windows will be atomic, low-latency, low tail latency, and shall never deadlock.
73 lines
3.6 KiB
C
73 lines
3.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│ vi: set et 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/calls/cp.internal.h"
|
|
#include "libc/calls/internal.h"
|
|
#include "libc/calls/sig.internal.h"
|
|
#include "libc/calls/struct/sigset.h"
|
|
#include "libc/calls/struct/sigset.internal.h"
|
|
#include "libc/dce.h"
|
|
#include "libc/errno.h"
|
|
#include "libc/intrin/atomic.h"
|
|
#include "libc/intrin/strace.h"
|
|
#include "libc/nt/synchronization.h"
|
|
#include "libc/sysv/consts/sig.h"
|
|
#include "libc/sysv/errfuns.h"
|
|
#include "libc/thread/tls.h"
|
|
|
|
/**
|
|
* Blocks until SIG ∉ MASK is delivered to thread.
|
|
*
|
|
* This temporarily replaces the signal mask until a signal that it
|
|
* doesn't contain is delivered.
|
|
*
|
|
* @param ignore is a bitset of signals to block temporarily, which if
|
|
* NULL is equivalent to passing an empty signal set
|
|
* @return -1 w/ EINTR (or possibly EFAULT)
|
|
* @cancelationpoint
|
|
* @asyncsignalsafe
|
|
* @norestart
|
|
*/
|
|
int sigsuspend(const sigset_t *ignore) {
|
|
int rc;
|
|
BEGIN_CANCELATION_POINT;
|
|
|
|
if (IsXnu() || IsOpenbsd()) {
|
|
// openbsd and xnu use a 32 signal register convention
|
|
rc = sys_sigsuspend(ignore ? (void *)(intptr_t)(uint32_t)*ignore : 0, 8);
|
|
} else {
|
|
sigset_t waitmask = ignore ? *ignore : 0;
|
|
if (IsWindows() || IsMetal()) {
|
|
// we don't strictly need to block signals, but it reduces signal
|
|
// delivery latency, by preventing other threads from delivering a
|
|
// signal asynchronously. it takes about ~5us to deliver a signal
|
|
// using SetEvent() whereas it takes ~30us to use SuspendThread(),
|
|
// GetThreadContext(), SetThreadContext(), and ResumeThread().
|
|
BLOCK_SIGNALS;
|
|
while (!(rc = _park_norestart(-1u, waitmask)))
|
|
donothing;
|
|
ALLOW_SIGNALS;
|
|
} else {
|
|
rc = sys_sigsuspend((uint64_t[2]){waitmask}, 8);
|
|
}
|
|
}
|
|
|
|
END_CANCELATION_POINT;
|
|
STRACE("sigsuspend(%s) → %d% m", DescribeSigset(0, ignore), rc);
|
|
return rc;
|
|
}
|