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https://github.com/jart/cosmopolitan.git
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197aa0d465
This change introduces support for Linux-style uc_context manipulation that's fast and works well on all supported OSes and architectures. It also integrates with the Cosmpolitan runtime which can show backtraces comprised of multiple stacks and fibers. See the test and example code for further details. This will be used by Mold once it's been vendored
80 lines
4.1 KiB
C
80 lines
4.1 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/dce.h"
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#include "libc/errno.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/thread/thread.h"
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/**
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* Configures custom allocated stack for thread, e.g.
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*
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* pthread_t id;
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* pthread_attr_t attr;
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* char *stk = NewCosmoStack();
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* pthread_attr_init(&attr);
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* pthread_attr_setstack(&attr, stk, GetStackSize());
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* pthread_create(&id, &attr, func, 0);
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* pthread_attr_destroy(&attr);
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* pthread_join(id, 0);
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* FreeCosmoStack(stk);
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*
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* Your stack must have at least `PTHREAD_STACK_MIN` bytes, which
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* Cosmpolitan Libc defines as `GetStackSize()`. It's a link-time
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* constant used by Actually Portable Executable that's 128 kb by
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* default. See libc/runtime/stack.h for docs on your stack limit
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* since the APE ELF phdrs are the one true source of truth here.
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*
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* Cosmpolitan Libc runtime magic (e.g. ftrace) and memory safety
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* (e.g. kprintf) assumes that stack sizes are two-powers and are
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* aligned to that two-power. Conformance isn't required since we
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* say caveat emptor to those who don't maintain these invariants
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* please consider using NewCosmoStack(), which is always perfect
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* or use `mmap(0, GetStackSize() << 1, ...)` for a bigger stack.
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*
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* Unlike pthread_attr_setstacksize(), this function permits just
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* about any parameters and will change the values and allocation
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* as needed to conform to the mandatory requirements of the host
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* operating system even if it doesn't meet the stricter needs of
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* Cosmopolitan Libc userspace libraries. For example with malloc
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* allocations, things like page size alignment, shall be handled
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* automatically for compatibility with existing codebases.
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*
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* @param stackaddr is address of stack allocated by caller, and
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* may be NULL in which case default behavior is restored
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* @param stacksize is size of caller allocated stack
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* @return 0 on success, or errno on error
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* @raise EINVAL if parameters were unacceptable
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* @see pthread_attr_setstacksize()
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*/
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errno_t pthread_attr_setstack(pthread_attr_t *attr, void *stackaddr,
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size_t stacksize) {
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if (!stackaddr) {
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attr->__stackaddr = 0;
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attr->__stacksize = 0;
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return 0;
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}
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if (stacksize < PTHREAD_STACK_MIN ||
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(IsAsan() && !__asan_is_valid(stackaddr, stacksize))) {
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return EINVAL;
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}
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attr->__stackaddr = stackaddr;
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attr->__stacksize = stacksize;
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return 0;
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}
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