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ae638c0850
- Get clone() working on FreeBSD - Increase some Python build quotas - Add more atomic builtins to chibicc - Fix ASAN poisoning of alloca() memory - Make MODE= mandatory link path tinier - Improve the examples folder a little bit - Start working on some more resource limits - Make the linenoise auto-complete UI as good as GNU readline - Update compile.com, avoiding AVX codegen on non-AVX systems - Make sure empty path to syscalls like opendir raises ENOENT - Correctly polyfill ENOENT vs. ENOTDIR on the New Technology - Port bestline's paredit features to //third_party/linenoise - Remove workarounds for RHEL 5.0 bugs that were fixed in 5.1
44 lines
2 KiB
C
44 lines
2 KiB
C
#if 0
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/*─────────────────────────────────────────────────────────────────╗
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│ To the extent possible under law, Justine Tunney has waived │
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│ all copyright and related or neighboring rights to this file, │
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│ as it is written in the following disclaimers: │
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│ • http://unlicense.org/ │
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│ • http://creativecommons.org/publicdomain/zero/1.0/ │
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╚─────────────────────────────────────────────────────────────────*/
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#endif
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#include "libc/calls/calls.h"
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#include "libc/calls/struct/sigaction.h"
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#include "libc/calls/struct/siginfo.h"
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#include "libc/calls/ucontext.h"
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#include "libc/stdio/stdio.h"
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#include "libc/sysv/consts/sa.h"
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#include "libc/sysv/consts/sig.h"
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#include "third_party/xed/x86.h"
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/**
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* @fileoverview How to change CPU state on signal delivery
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*
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* This program redefines division by zero so that it has a definition.
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* The definition is the meaning of life, the universe, and everything.
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* Normally crash signals like `SIGSEGV`, `SIGILL`, and `SIGFPE` aren't
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* recoverable. This example shows how it actually can be done with Xed
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* and this example should work on all supported platforms even Windows
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*/
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void handler(int sig, siginfo_t *si, ucontext_t *ctx) {
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struct XedDecodedInst xedd;
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xed_decoded_inst_zero_set_mode(&xedd, XED_MACHINE_MODE_LONG_64);
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xed_instruction_length_decode(&xedd, (void *)ctx->uc_mcontext.rip, 15);
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ctx->uc_mcontext.rip += xedd.length;
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ctx->uc_mcontext.rax = 42; // set the DIV result registers rdx:rax
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ctx->uc_mcontext.rdx = 0;
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}
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int main(int argc, char *argv[]) {
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struct sigaction saint = {.sa_sigaction = handler, .sa_flags = SA_SIGINFO};
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sigaction(SIGFPE, &saint, NULL);
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volatile long x = 0;
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printf("123/0 = %ld\n", 123 / x);
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return 0;
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}
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