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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
64 lines
3 KiB
C
64 lines
3 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/calls/calls.h"
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#include "libc/dce.h"
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#include "libc/intrin/asan.internal.h"
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#include "libc/intrin/asancodes.h"
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#include "libc/runtime/memtrack.internal.h"
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#include "libc/runtime/runtime.h"
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#include "libc/runtime/stack.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/prot.h"
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/**
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* Allocates stack.
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*
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* The size of your returned stack is always GetStackSize().
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*
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* The bottom 4096 bytes of your stack can't be used, since it's always
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* reserved for a read-only guard page. With ASAN it'll be poisoned too.
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*
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* The top 16 bytes of a stack can't be used due to openbsd:stackbound
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* and those bytes are also poisoned under ASAN build modes.
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*
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* @return stack bottom address on success, or null w/ errno
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*/
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void *NewCosmoStack(void) {
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char *p;
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if ((p = mmap(0, GetStackSize(), PROT_READ | PROT_WRITE,
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MAP_STACK | MAP_ANONYMOUS, -1, 0)) != MAP_FAILED) {
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if (IsAsan()) {
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__asan_poison(p + GetStackSize() - 16, 16, kAsanStackOverflow);
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__asan_poison(p, 4096, kAsanStackOverflow);
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}
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return p;
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} else {
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return 0;
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}
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}
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/**
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* Frees stack.
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*
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* @param stk was allocated by NewCosmoStack()
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*/
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int FreeCosmoStack(void *stk) {
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return munmap(stk, GetStackSize());
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}
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