mirror of
https://github.com/jart/cosmopolitan.git
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74 lines
3.7 KiB
C
74 lines
3.7 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/safemacros.internal.h"
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#include "libc/mem/mem.h"
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#include "libc/runtime/interruptiblecall.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sig.h"
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STATIC_YOINK("_init_onntconsoleevent");
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static struct InterruptibleCall *g_interruptiblecall;
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wontreturn static void interruptcall(int sig) {
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longjmp(g_interruptiblecall->jb, 1);
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unreachable;
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}
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/**
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* Calls function that may be cancelled by a signal.
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*
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* @param state is allocated and zero'd by the caller; state→sig and
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* state→sa_new.sa_mask may be set; it may be re-used w/o
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* reinitializing; it may be static or heap memory; it may be stack
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* memory if re-entrant behavior isn't needed
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* @return the value returned by callback or -1 on interrupt; they may
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* be differentiated using the state→returnval filed, which is only
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* modified by this function when callbacks succeed
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*/
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intptr_t interruptiblecall(struct InterruptibleCall *icall,
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intptr_t callback(intptr_t p1, intptr_t p2,
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intptr_t p3, intptr_t p4),
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intptr_t p1, intptr_t p2, intptr_t p3, intptr_t p4) {
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intptr_t rc;
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if (!icall->sig) icall->sig = SIGINT;
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icall->sa_new.sa_handler = interruptcall;
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icall->sa_new.sa_flags |= SA_RESTART | SA_RESETHAND;
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if ((rc = (sigaction)(icall->sig, &icall->sa_new, &icall->sa_old)) != -1) {
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icall->prev = g_interruptiblecall;
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g_interruptiblecall = icall;
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if (!setjmp(icall->jb)) {
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icall->returnval = rc = callback(p1, p2, p3, p4);
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} else {
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rc = -1;
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}
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asm volatile("" ::: "memory");
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struct InterruptibleCall *unwind;
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for (;;) {
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unwind = g_interruptiblecall;
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(sigaction)(unwind->sig, &unwind->sa_old, NULL);
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g_interruptiblecall = unwind->prev;
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if (unwind == icall) break;
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free_s(&unwind);
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}
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icall->prev = NULL;
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}
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return rc;
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}
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