54 lines
3.1 KiB
C
54 lines
3.1 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/calls/calls.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/sig.h"
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#include "libc/x/x.h"
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/**
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* Installs handler for kernel interrupt, e.g.:
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*
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* onctrlc(sig) { exit(128+sig); }
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* CHECK_NE(-1, xsigaction(SIGINT, onctrlc, SA_RESETHAND, 0, 0));
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*
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* @param sig can be SIGINT, SIGTERM, etc.
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* @param handler is SIG_DFL, SIG_IGN, or a pointer to a 0≤arity≤3
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* callback function passed (sig, siginfo_t *, ucontext_t *).
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* @param flags can have SA_RESETHAND, SA_RESTART, SA_SIGINFO, etc.
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* @param mask is 1ul«SIG₁[…|1ul«SIGₙ] bitset to block in handler
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* @param old optionally receives previous handler
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* @return 0 on success, or -1 w/ errno
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* @see libc/sysv/consts.sh
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* @asyncsignalsafe
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*/
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int xsigaction(int sig, void *handler, uint64_t flags, uint64_t mask,
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struct sigaction *old) {
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/* This API is superior to sigaction() because (1) it offers feature
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parity; (2) compiler emits 1/3rd as much binary code at call-site;
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and (3) it removes typing that just whines without added saftey. */
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_handler = handler;
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sa.sa_flags = flags;
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memcpy(&sa.sa_mask, &mask, sizeof(mask));
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return sigaction(sig, &sa, old);
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}
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