76 lines
3.8 KiB
C
76 lines
3.8 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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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/bits/progn.h"
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#include "libc/bits/safemacros.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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noreturn 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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g_interruptiblecall = PROGN((icall->prev = 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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