/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│ │vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│ ╞══════════════════════════════════════════════════════════════════════════════╡ │ Copyright 2020 Justine Alexandra Roberts Tunney │ │ │ │ This program is free software; you can redistribute it and/or modify │ │ it under the terms of the GNU General Public License as published by │ │ the Free Software Foundation; version 2 of the License. │ │ │ │ This program is distributed in the hope that it will be useful, but │ │ WITHOUT ANY WARRANTY; without even the implied warranty of │ │ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │ │ General Public License for more details. │ │ │ │ You should have received a copy of the GNU General Public License │ │ along with this program; if not, write to the Free Software │ │ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │ │ 02110-1301 USA │ ╚─────────────────────────────────────────────────────────────────────────────*/ #include "libc/calls/calls.h" #include "libc/calls/struct/sigaction.h" #include "libc/str/str.h" #include "libc/sysv/consts/sig.h" #include "libc/x/x.h" /** * Installs handler for kernel interrupt, e.g.: * * onctrlc(sig) { exit(128+sig); } * CHECK_NE(-1, xsigaction(SIGINT, onctrlc, SA_RESETHAND, 0, 0)); * * @param sig can be SIGINT, SIGTERM, etc. * @param handler is SIG_DFL, SIG_IGN, or a pointer to a 0≤arity≤3 * callback function passed (sig, siginfo_t *, ucontext_t *). * @param flags can have SA_RESETHAND, SA_RESTART, SA_SIGINFO, etc. * @param mask is 1ul«SIG₁[…|1ul«SIGₙ] bitset to block in handler * @param old optionally receives previous handler * @return 0 on success, or -1 w/ errno * @see libc/sysv/consts.sh * @asyncsignalsafe */ int xsigaction(int sig, void *handler, uint64_t flags, uint64_t mask, struct sigaction *old) { /* This API is superior to sigaction() because (1) it offers feature parity; (2) compiler emits 1/3rd as much binary code at call-site; and (3) it removes typing that just whines without added saftey. */ struct sigaction sa; memset(&sa, 0, sizeof(sa)); sa.sa_handler = handler; sa.sa_flags = flags; memcpy(&sa.sa_mask, &mask, sizeof(mask)); return sigaction(sig, &sa, old); }