cosmopolitan/libc/calls/signal.c
Justine Tunney 046c7ebd4a Improve locks and signals
- Introduce fast spinlock API
- Double rand64() perf w/ spinlock
- Improve raise() on New Technology
- Support gettid() across platforms
- Implement SA_NODEFER on New Technology
- Move the lock intrinsics into LIBC_INTRIN
- Make SIGTRAP recoverable on New Technology
- Block SIGCHLD in wait4() on New Technology
- Add threading prototypes for XNU and FreeBSD
- Rewrite abort() fixing its minor bugs on XNU/NT
- Shave down a lot of the content in libc/bits/bits.h
- Let signal handlers modify CPU registers on New Technology
2022-04-12 05:20:17 -07:00

40 lines
2.4 KiB
C

/*-*- mode:c; indent-tabs-mode:nil; tab-width:2; coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/sigaction.h"
#include "libc/sysv/consts/sa.h"
/**
* Installs kernel interrupt handler, e.g.
*
* void GotCtrlC(int sig) { ... }
* CHECK_NE(SIG_ERR, signal(SIGINT, GotCtrlC));
*
* @return old signal handler on success or SIG_ERR w/ errno
* @note this function has BSD semantics, i.e. SA_RESTART
* @see sigaction() which has more features
*/
sighandler_t(signal)(int sig, sighandler_t func) {
struct sigaction old, sa = {.sa_handler = func, .sa_flags = SA_RESTART};
if ((sigaction)(sig, &sa, &old) != -1) {
return old.sa_handler;
} else {
return SIG_ERR;
}
}