cosmopolitan/libc/thread/mapstack.c
2024-12-25 20:58:08 -08:00

56 lines
2.8 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 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/cosmo.h"
#include "libc/errno.h"
#include "libc/runtime/stack.h"
/**
* Allocates stack.
*
* The size of your returned stack is always GetStackSize().
*
* The bottom 4096 bytes of your stack can't be used, since it's always
* reserved for a read-only guard page. With ASAN it'll be poisoned too.
*
* The top 16 bytes of a stack can't be used due to openbsd:stackbound
* and those bytes are also poisoned under ASAN build modes.
*
* @return stack bottom address on success, or null w/ errno
*/
void *NewCosmoStack(void) {
void *stackaddr;
size_t stacksize = GetStackSize();
size_t guardsize = GetGuardSize();
errno_t err = cosmo_stack_alloc(&stacksize, &guardsize, &stackaddr);
if (!err)
return stackaddr;
errno = err;
return 0;
}
/**
* Frees stack.
*
* @param stackaddr was allocated by NewCosmoStack()
* @return 0 on success, or -1 w/ errno
*/
int FreeCosmoStack(void *stackaddr) {
cosmo_stack_free(stackaddr, GetStackSize(), GetGuardSize());
return 0;
}