mirror of
https://github.com/jart/cosmopolitan.git
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118 lines
4.4 KiB
C
118 lines
4.4 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 2021 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/struct/sigaltstack.h"
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#include "libc/calls/struct/metasigaltstack.h"
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#include "libc/calls/struct/sigaltstack.internal.h"
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#include "libc/calls/syscall-sysv.internal.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/describeflags.internal.h"
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#include "libc/intrin/strace.internal.h"
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#include "libc/sysv/consts/ss.h"
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#include "libc/sysv/errfuns.h"
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static void sigaltstack2bsd(struct sigaltstack_bsd *bsd,
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const struct sigaltstack *linux) {
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void *sp;
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int flags;
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size_t size;
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sp = linux->ss_sp;
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flags = linux->ss_flags;
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size = linux->ss_size;
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bsd->ss_sp = sp;
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bsd->ss_flags = flags;
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bsd->ss_size = size;
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}
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static void sigaltstack2linux(struct sigaltstack *linux,
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const struct sigaltstack_bsd *bsd) {
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void *sp;
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int flags;
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size_t size;
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sp = bsd->ss_sp;
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flags = bsd->ss_flags;
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size = bsd->ss_size;
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linux->ss_sp = sp;
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linux->ss_flags = flags;
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linux->ss_size = size;
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}
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/**
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* Sets and/or gets alternate signal stack, e.g.
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*
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* struct sigaction sa;
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* struct sigaltstack ss;
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* ss.ss_flags = 0;
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* ss.ss_sp = NewCosmoStack();
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* ss.ss_size = GetStackSize();
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* sigaltstack(&ss, 0);
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* sigemptyset(&sa.ss_mask);
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* sa.sa_flags = SA_ONSTACK;
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* sa.sa_handler = OnStackOverflow;
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* sigaction(SIGSEGV, &sa, 0);
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*
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* @param neu if non-null will install new signal alt stack
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* @param old if non-null will receive current signal alt stack
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* @return 0 on success, or -1 w/ errno
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* @raise EFAULT if bad memory was supplied
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* @raise ENOMEM if `neu->ss_size` is less than `MINSIGSTKSZ`
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*/
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int sigaltstack(const struct sigaltstack *neu, struct sigaltstack *old) {
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int rc;
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void *b;
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const void *a;
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struct sigaltstack_bsd bsd;
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if (IsAsan() && ((old && !__asan_is_valid(old, sizeof(*old))) ||
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(neu && !__asan_is_valid(neu, sizeof(*neu))))) {
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rc = efault();
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} else if (neu && neu->ss_size < MINSIGSTKSZ) {
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rc = enomem();
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} else if (IsLinux() || IsBsd()) {
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if (IsLinux()) {
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a = neu;
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b = old;
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} else {
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if (neu) {
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sigaltstack2bsd(&bsd, neu);
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a = &bsd;
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} else {
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a = 0;
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}
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if (old) {
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b = &bsd;
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} else {
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b = 0;
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}
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}
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if ((rc = sys_sigaltstack(a, b)) != -1) {
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if (IsBsd() && old) {
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sigaltstack2linux(old, &bsd);
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}
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rc = 0;
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} else {
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rc = -1;
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}
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} else {
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rc = enosys();
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}
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STRACE("sigaltstack(%s, [%s]) → %d% m", DescribeSigaltstk(0, neu),
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DescribeSigaltstk(0, old), rc);
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return rc;
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}
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