mirror of
https://github.com/autc04/Retro68.git
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292 lines
8.1 KiB
C
292 lines
8.1 KiB
C
/* go-signal.c -- signal handling for Go.
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Copyright 2009 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/time.h>
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#include <ucontext.h>
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#include "runtime.h"
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#ifndef SA_RESTART
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#define SA_RESTART 0
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#endif
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#ifdef USING_SPLIT_STACK
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extern void __splitstack_getcontext(void *context[10]);
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extern void __splitstack_setcontext(void *context[10]);
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extern void *__splitstack_find_context(void *context[10], size_t *,
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void **, void **, void **);
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#endif
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// The rest of the signal handler, written in Go.
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extern void sigtrampgo(uint32, siginfo_t *, void *)
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__asm__(GOSYM_PREFIX "runtime.sigtrampgo");
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// The Go signal handler, written in C. This should be running on the
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// alternate signal stack. This is responsible for setting up the
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// split stack context so that stack guard checks will work as
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// expected.
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void sigtramp(int, siginfo_t *, void *)
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__attribute__ ((no_split_stack));
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void sigtramp(int, siginfo_t *, void *)
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__asm__ (GOSYM_PREFIX "runtime.sigtramp");
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#ifndef USING_SPLIT_STACK
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// When not using split stacks, there are no stack checks, and there
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// is nothing special for this function to do.
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void
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sigtramp(int sig, siginfo_t *info, void *context)
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{
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sigtrampgo(sig, info, context);
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}
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#else // USING_SPLIT_STACK
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void
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sigtramp(int sig, siginfo_t *info, void *context)
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{
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G *gp;
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void *stack_context[10];
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void *stack;
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size_t stack_size;
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void *next_segment;
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void *next_sp;
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void *initial_sp;
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uintptr sp;
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stack_t st;
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uintptr stsp;
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gp = runtime_g();
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if (gp == nil) {
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// Let the Go code handle this case.
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// It should only call nosplit functions in this case.
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sigtrampgo(sig, info, context);
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return;
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}
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// If this signal is one for which we will panic, we are not
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// on the alternate signal stack. It's OK to call split-stack
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// functions here.
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if (sig == SIGBUS || sig == SIGFPE || sig == SIGSEGV) {
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sigtrampgo(sig, info, context);
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return;
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}
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// We are running on the alternate signal stack.
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__splitstack_getcontext(&stack_context[0]);
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stack = __splitstack_find_context(&gp->m->gsignal->stackcontext[0],
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&stack_size, &next_segment,
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&next_sp, &initial_sp);
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// If some non-Go code called sigaltstack, adjust.
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sp = (uintptr)(&stack_size);
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if (sp < (uintptr)(stack) || sp >= (uintptr)(stack) + stack_size) {
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sigaltstack(nil, &st);
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if ((st.ss_flags & SS_DISABLE) != 0) {
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runtime_printf("signal %d received on thread with no signal stack\n", (int32)(sig));
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runtime_throw("non-Go code disabled sigaltstack");
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}
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stsp = (uintptr)(st.ss_sp);
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if (sp < stsp || sp >= stsp + st.ss_size) {
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runtime_printf("signal %d received but handler not on signal stack\n", (int32)(sig));
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runtime_throw("non-Go code set up signal handler without SA_ONSTACK flag");
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}
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// Unfortunately __splitstack_find_context will return NULL
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// when it is called on a context that has never been used.
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// There isn't much we can do but assume all is well.
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if (stack != NULL) {
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// Here the gc runtime adjusts the gsignal
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// stack guard to match the values returned by
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// sigaltstack. Unfortunately we have no way
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// to do that.
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runtime_printf("signal %d received on unknown signal stack\n", (int32)(sig));
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runtime_throw("non-Go code changed signal stack");
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}
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}
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// Set the split stack context so that the stack guards are
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// checked correctly.
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__splitstack_setcontext(&gp->m->gsignal->stackcontext[0]);
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sigtrampgo(sig, info, context);
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// We are going to return back to the signal trampoline and
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// then to whatever we were doing before we got the signal.
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// Restore the split stack context so that stack guards are
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// checked correctly.
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__splitstack_setcontext(&stack_context[0]);
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}
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#endif // USING_SPLIT_STACK
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// C function to return the address of the sigtramp function.
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uintptr getSigtramp(void) __asm__ (GOSYM_PREFIX "runtime.getSigtramp");
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uintptr
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getSigtramp()
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{
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return (uintptr)(void*)sigtramp;
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}
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// C code to manage the sigaction sa_sigaction field, which is
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// typically a union and so hard for mksysinfo.sh to handle.
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uintptr getSigactionHandler(struct sigaction*)
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__attribute__ ((no_split_stack));
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uintptr getSigactionHandler(struct sigaction*)
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__asm__ (GOSYM_PREFIX "runtime.getSigactionHandler");
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uintptr
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getSigactionHandler(struct sigaction* sa)
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{
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return (uintptr)(sa->sa_sigaction);
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}
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void setSigactionHandler(struct sigaction*, uintptr)
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__attribute__ ((no_split_stack));
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void setSigactionHandler(struct sigaction*, uintptr)
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__asm__ (GOSYM_PREFIX "runtime.setSigactionHandler");
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void
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setSigactionHandler(struct sigaction* sa, uintptr handler)
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{
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sa->sa_sigaction = (void*)(handler);
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}
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// C code to fetch values from the siginfo_t and ucontext_t pointers
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// passed to a signal handler.
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struct getSiginfoRet {
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uintptr sigaddr;
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uintptr sigpc;
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};
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struct getSiginfoRet getSiginfo(siginfo_t *, void *)
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__asm__(GOSYM_PREFIX "runtime.getSiginfo");
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struct getSiginfoRet
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getSiginfo(siginfo_t *info, void *context __attribute__((unused)))
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{
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struct getSiginfoRet ret;
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Location loc[1];
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int32 n;
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if (info == nil) {
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ret.sigaddr = 0;
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} else {
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ret.sigaddr = (uintptr)(info->si_addr);
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}
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ret.sigpc = 0;
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// There doesn't seem to be a portable way to get the PC.
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// Use unportable code to pull it from context, and if that fails
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// try a stack backtrace across the signal handler.
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#ifdef __x86_64__
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#ifdef __linux__
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ret.sigpc = ((ucontext_t*)(context))->uc_mcontext.gregs[REG_RIP];
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#endif
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#endif
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#ifdef __i386__
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#ifdef __linux__
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ret.sigpc = ((ucontext_t*)(context))->uc_mcontext.gregs[REG_EIP];
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#endif
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#endif
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if (ret.sigpc == 0) {
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// Skip getSiginfo/sighandler/sigtrampgo/sigtramp/handler.
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n = runtime_callers(5, &loc[0], 1, false);
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if (n > 0) {
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ret.sigpc = loc[0].pc;
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}
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}
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return ret;
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}
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// Dump registers when crashing in a signal.
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// There is no portable way to write this,
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// so we just have some CPU/OS specific implementations.
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void dumpregs(siginfo_t *, void *)
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__asm__(GOSYM_PREFIX "runtime.dumpregs");
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void
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dumpregs(siginfo_t *info __attribute__((unused)), void *context __attribute__((unused)))
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{
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#ifdef __x86_64__
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#ifdef __linux__
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{
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mcontext_t *m = &((ucontext_t*)(context))->uc_mcontext;
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runtime_printf("rax %X\n", m->gregs[REG_RAX]);
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runtime_printf("rbx %X\n", m->gregs[REG_RBX]);
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runtime_printf("rcx %X\n", m->gregs[REG_RCX]);
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runtime_printf("rdx %X\n", m->gregs[REG_RDX]);
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runtime_printf("rdi %X\n", m->gregs[REG_RDI]);
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runtime_printf("rsi %X\n", m->gregs[REG_RSI]);
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runtime_printf("rbp %X\n", m->gregs[REG_RBP]);
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runtime_printf("rsp %X\n", m->gregs[REG_RSP]);
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runtime_printf("r8 %X\n", m->gregs[REG_R8]);
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runtime_printf("r9 %X\n", m->gregs[REG_R9]);
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runtime_printf("r10 %X\n", m->gregs[REG_R10]);
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runtime_printf("r11 %X\n", m->gregs[REG_R11]);
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runtime_printf("r12 %X\n", m->gregs[REG_R12]);
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runtime_printf("r13 %X\n", m->gregs[REG_R13]);
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runtime_printf("r14 %X\n", m->gregs[REG_R14]);
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runtime_printf("r15 %X\n", m->gregs[REG_R15]);
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runtime_printf("rip %X\n", m->gregs[REG_RIP]);
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runtime_printf("rflags %X\n", m->gregs[REG_EFL]);
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runtime_printf("cs %X\n", m->gregs[REG_CSGSFS] & 0xffff);
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runtime_printf("fs %X\n", (m->gregs[REG_CSGSFS] >> 16) & 0xffff);
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runtime_printf("gs %X\n", (m->gregs[REG_CSGSFS] >> 32) & 0xffff);
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}
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#endif
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#endif
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#ifdef __i386__
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#ifdef __linux__
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{
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mcontext_t *m = &((ucontext_t*)(context))->uc_mcontext;
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runtime_printf("eax %X\n", m->gregs[REG_EAX]);
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runtime_printf("ebx %X\n", m->gregs[REG_EBX]);
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runtime_printf("ecx %X\n", m->gregs[REG_ECX]);
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runtime_printf("edx %X\n", m->gregs[REG_EDX]);
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runtime_printf("edi %X\n", m->gregs[REG_EDI]);
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runtime_printf("esi %X\n", m->gregs[REG_ESI]);
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runtime_printf("ebp %X\n", m->gregs[REG_EBP]);
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runtime_printf("esp %X\n", m->gregs[REG_ESP]);
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runtime_printf("eip %X\n", m->gregs[REG_EIP]);
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runtime_printf("eflags %X\n", m->gregs[REG_EFL]);
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runtime_printf("cs %X\n", m->gregs[REG_CS]);
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runtime_printf("fs %X\n", m->gregs[REG_FS]);
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runtime_printf("gs %X\n", m->gregs[REG_GS]);
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}
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#endif
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#endif
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}
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