src/pkg/runtime/linux/amd64/signal.c

// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include "runtime.h"
#include "defs.h"
#include "signals.h"
#include "os.h"

void
dumpregs(Sigcontext *r)
{
	printf("rax     %X\n", r->rax);
	printf("rbx     %X\n", r->rbx);
	printf("rcx     %X\n", r->rcx);
	printf("rdx     %X\n", r->rdx);
	printf("rdi     %X\n", r->rdi);
	printf("rsi     %X\n", r->rsi);
	printf("rbp     %X\n", r->rbp);
	printf("rsp     %X\n", r->rsp);
	printf("r8      %X\n", r->r8 );
	printf("r9      %X\n", r->r9 );
	printf("r10     %X\n", r->r10);
	printf("r11     %X\n", r->r11);
	printf("r12     %X\n", r->r12);
	printf("r13     %X\n", r->r13);
	printf("r14     %X\n", r->r14);
	printf("r15     %X\n", r->r15);
	printf("rip     %X\n", r->rip);
	printf("rflags  %X\n", r->eflags);
	printf("cs      %X\n", (uint64)r->cs);
	printf("fs      %X\n", (uint64)r->fs);
	printf("gs      %X\n", (uint64)r->gs);
}

/*
 * This assembler routine takes the args from registers, puts them on the stack,
 * and calls sighandler().
 */
extern void sigtramp(void);
extern void sigignore(void);	// just returns
extern void sigreturn(void);	// calls sigreturn

void
sighandler(int32 sig, Siginfo* info, void* context)
{
	Ucontext *uc;
	Mcontext *mc;
	Sigcontext *sc;

	if(panicking)	// traceback already printed
		exit(2);
	panicking = 1;

	uc = context;
	mc = &uc->uc_mcontext;
	sc = (Sigcontext*)mc;	// same layout, more conveient names

	if(sig < 0 || sig >= NSIG)
		printf("Signal %d\n", sig);
	else
		printf("%s\n", sigtab[sig].name);

	printf("Faulting address: %p\n", *(void**)info->_sifields);
	printf("PC=%X\n", sc->rip);
	printf("\n");

	if(gotraceback()){
		traceback((void*)sc->rip, (void*)sc->rsp, (void*)sc->r15);
		tracebackothers((void*)sc->r15);
		dumpregs(sc);
	}

	breakpoint();
	exit(2);
}

void
signalstack(byte *p, int32 n)
{
	Sigaltstack st;

	st.ss_sp = p;
	st.ss_size = n;
	st.ss_flags = 0;
	sigaltstack(&st, nil);
}

void
initsig(void)
{
	static Sigaction sa;

	int32 i;
	sa.sa_flags = SA_ONSTACK | SA_SIGINFO | SA_RESTORER;
	sa.sa_mask = 0xFFFFFFFFFFFFFFFFULL;
	sa.sa_restorer = (void*)sigreturn;
	for(i = 0; i<NSIG; i++) {
		if(sigtab[i].flags) {
			if(sigtab[i].flags & SigCatch)
				sa.sa_handler = (void*)sigtramp;
			else
				sa.sa_handler = (void*)sigignore;
			if(sigtab[i].flags & SigRestart)
				sa.sa_flags |= SA_RESTART;
			else
				sa.sa_flags &= ~SA_RESTART;
			rt_sigaction(i, &sa, nil, 8);
		}
	}
}