cosmopolitan/libc/thread/pthread_attr_setstack.c
Jōshin e16a7d8f3b
flip et / noet in modelines
`et` means `expandtab`.

```sh
rg 'vi: .* :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\)  :vi/vi: \1 xoet\2:vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2  :vi/'
rg 'vi: .*  :vi' -l -0 | \
  xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/'
```
2023-12-07 22:17:11 -05:00

83 lines
4.3 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/dce.h"
#include "libc/errno.h"
#include "libc/intrin/asan.internal.h"
#include "libc/thread/thread.h"
/**
* Configures custom allocated stack for thread, e.g.
*
* pthread_t id;
* pthread_attr_t attr;
* char *stk = NewCosmoStack();
* pthread_attr_init(&attr);
* pthread_attr_setstack(&attr, stk, GetStackSize());
* pthread_create(&id, &attr, func, 0);
* pthread_attr_destroy(&attr);
* pthread_join(id, 0);
* FreeCosmoStack(stk);
*
* Your stack must have at least `PTHREAD_STACK_MIN` bytes, which
* Cosmpolitan Libc defines as `GetStackSize()`. It's a link-time
* constant used by Actually Portable Executable that's 128 kb by
* default. See libc/runtime/stack.h for docs on your stack limit
* since the APE ELF phdrs are the one true source of truth here.
*
* Cosmpolitan Libc runtime magic (e.g. ftrace) and memory safety
* (e.g. kprintf) assumes that stack sizes are two-powers and are
* aligned to that two-power. Conformance isn't required since we
* say caveat emptor to those who don't maintain these invariants
* please consider using NewCosmoStack(), which is always perfect
* or use `mmap(0, GetStackSize() << 1, ...)` for a bigger stack.
*
* Unlike pthread_attr_setstacksize(), this function permits just
* about any parameters and will change the values and allocation
* as needed to conform to the mandatory requirements of the host
* operating system even if it doesn't meet the stricter needs of
* Cosmopolitan Libc userspace libraries. For example with malloc
* allocations, things like page size alignment, shall be handled
* automatically for compatibility with existing codebases.
*
* The same stack shouldn't be used for two separate threads. Use
* fresh stacks for each thread so that ASAN can be much happier.
*
* @param stackaddr is address of stack allocated by caller, and
* may be NULL in which case default behavior is restored
* @param stacksize is size of caller allocated stack
* @return 0 on success, or errno on error
* @raise EINVAL if parameters were unacceptable
* @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 = 0;
return 0;
}
if (stacksize < PTHREAD_STACK_MIN ||
(IsAsan() && !__asan_is_valid(stackaddr, stacksize))) {
return EINVAL;
}
attr->__stackaddr = stackaddr;
attr->__stacksize = stacksize;
return 0;
}