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

60 lines
3.4 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/errno.h"
#include "libc/runtime/stack.h"
#include "libc/thread/thread.h"
/**
* Configures custom stack for thread.
*
* Normally you want to use pthread_attr_setstacksize() and
* pthread_attr_setguardsize() to configure how pthread_create()
* allocates stack memory for newly created threads. Cosmopolitan is
* very good at managing stack memory. However if you still want to
* allocate stack memory on your own, POSIX defines this function.
*
* Your `stackaddr` points to the byte at the very bottom of your stack.
* You are responsible for this memory. Your POSIX threads runtime will
* not free or unmap this allocation when the thread has terminated. If
* `stackaddr` is null then `stacksize` is ignored and default behavior
* is restored, i.e. pthread_create() will manage stack allocations.
*
* Your `stackaddr` could be created by malloc(). On OpenBSD,
* pthread_create() will augment your custom allocation so it's
* permissable by the kernel to use as a stack. You may also call
* Cosmopolitan APIs such NewCosmoStack() and cosmo_stack_alloc().
* Static memory can be used, but it won't reduce pthread footprint.
*
* @return 0 on success, or errno on error
* @raise EINVAL if `stacksize` is less than `PTHREAD_STACK_MIN`
* @see pthread_attr_setstacksize()
*/
errno_t pthread_attr_setstack(pthread_attr_t *attr, void *stackaddr,
size_t stacksize) {
if (!stackaddr) {
attr->__stackaddr = 0;
attr->__stacksize = GetStackSize();
return 0;
}
if (stacksize < PTHREAD_STACK_MIN)
return EINVAL;
attr->__stackaddr = stackaddr;
attr->__stacksize = stacksize;
return 0;
}