cosmopolitan/libc/calls/atfork.c

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2020-06-15 14:18:57 +00:00
/*-*- 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/macros.h"
#include "libc/runtime/runtime.h"
#include "libc/sysv/errfuns.h"
static struct AtFork {
size_t i;
struct AtForkCallback {
void (*fn)(void *);
void *arg;
} p[ATEXIT_MAX];
} g_atfork;
/**
* Registers function to be called when PID changes.
*
* @return 0 on success, or -1 w/ errno
*/
int atfork(void *fn, void *arg) {
if (g_atfork.i == ARRAYLEN(g_atfork.p)) return enomem();
g_atfork.p[g_atfork.i++] = (struct AtForkCallback){.fn = fn, .arg = arg};
return 0;
}
/**
* Triggers atfork() callbacks.
*
* Only fork() should call this.
*/
void __onfork(void) {
size_t i;
for (i = 0; i < g_atfork.i; ++i) {
g_atfork.p[i].fn(g_atfork.p[i].arg);
}
}