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https://github.com/jart/cosmopolitan.git
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97b7116953
After going through the MODE=dbg and MODE=zero build modes, a bunch of little issues were identified, which have been addressed. Fixing those issues created even more troubles for the project, because it improved our ability to detect latent problems which are getting fixed so fast.
59 lines
3 KiB
C
59 lines
3 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 2023 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/ucontext.h"
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#include "libc/calls/struct/sigset.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/sig.h"
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int __tailcontext(const ucontext_t *);
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static int __contextmask(const sigset_t *opt_set, sigset_t *opt_out_oldset) {
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if (!__interruptible) return 0;
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// signal handling functions might exist
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// now context switching needs to go 14x slower
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return sigprocmask(SIG_SETMASK, opt_set, opt_out_oldset);
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}
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/**
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* Sets machine context.
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*
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* This function goes 14x slower if sigaction() has ever been used to
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* install a signal handling function. If you don't care about signal
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* safety and just want fast fibers, then you may override the global
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* variable `__interruptible` to disable the sigprocmask() calls, for
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* pure userspace context switching.
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*
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* @return -1 on error w/ errno, otherwise won't return unless sent back
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* @see swapcontext()
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* @see makecontext()
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* @see getcontext()
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* @threadsafe
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*/
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int setcontext(const ucontext_t *uc) {
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if (__contextmask(&uc->uc_sigmask, 0)) return -1;
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return __tailcontext(uc);
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}
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int __getcontextsig(ucontext_t *uc) {
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return __contextmask(0, &uc->uc_sigmask);
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}
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int __swapcontextsig(ucontext_t *x, const ucontext_t *y) {
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return __contextmask(&y->uc_sigmask, &x->uc_sigmask);
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}
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