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Perform more low-level code cleanup

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Justine Tunney 2022-09-09 04:07:08 -07:00
parent c32e2d4486
commit 2d17ab016c
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42 changed files with 977 additions and 265 deletions
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112
libc/thread/pthread_attr_setstack.c
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@ -1,112 +0,0 @@
/*-*- 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 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/calls/calls.h"
#include "libc/calls/syscall-sysv.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/asan.internal.h"
#include "libc/intrin/pthread.h"
#include "libc/macros.internal.h"
#include "libc/runtime/stack.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#define MAP_ANON_OPENBSD 0x1000
#define MAP_STACK_OPENBSD 0x4000
/**
* Configures custom allocated stack for thread, e.g.
*
* pthread_t id;
* pthread_attr_t attr;
* char *stk = _mapstack();
* pthread_attr_init(&attr);
* pthread_attr_setstack(&attr, stk, GetStackSize());
* pthread_create(&id, &attr, func, 0);
* pthread_attr_destroy(&attr);
* pthread_join(id, 0);
* _freestack(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 _mapstack() which always does it 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.
*
* @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()
*/
int 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;
}
if (IsOpenbsd()) {
// OpenBSD: Only permits RSP to occupy memory that's been explicitly
// defined as stack memory. We need to squeeze the provided interval
// in order to successfully call mmap(), which will return EINVAL if
// these calculations should overflow.
size_t n;
int e, rc;
uintptr_t x, y;
n = stacksize;
x = (uintptr_t)stackaddr;
y = ROUNDUP(x, PAGESIZE);
n -= y - x;
n = ROUNDDOWN(n, PAGESIZE);
stackaddr = (void *)y;
stacksize = n;
e = errno;
if (__sys_mmap(stackaddr, stacksize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANON_OPENBSD | MAP_STACK_OPENBSD, -1, 0,
0) == MAP_FAILED) {
rc = errno;
errno = e;
return rc;
}
}
attr->stackaddr = stackaddr;
attr->stacksize = stacksize;
return 0;
}