text: // 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.
  
  // +build darwin dragonfly freebsd linux nacl netbsd openbsd
  
  #include "runtime.h"
  #include "defs_GOOS_GOARCH.h"
  #include "os_GOOS.h"
  #include "signal_GOOS_GOARCH.h"
  #include "signals_GOOS.h"
  
  void
  runtime·dumpregs(Siginfo *info, void *ctxt)
  {
  	USED(info);
  	USED(ctxt);
  
  	runtime·printf("trap    %x\n", SIG_TRAP(info, ctxt));
  	runtime·printf("error   %x\n", SIG_ERROR(info, ctxt));
  	runtime·printf("oldmask %x\n", SIG_OLDMASK(info, ctxt));
  	runtime·printf("r0      %x\n", SIG_R0(info, ctxt));
  	runtime·printf("r1      %x\n", SIG_R1(info, ctxt));
  	runtime·printf("r2      %x\n", SIG_R2(info, ctxt));
  	runtime·printf("r3      %x\n", SIG_R3(info, ctxt));
  	runtime·printf("r4      %x\n", SIG_R4(info, ctxt));
  	runtime·printf("r5      %x\n", SIG_R5(info, ctxt));
  	runtime·printf("r6      %x\n", SIG_R6(info, ctxt));
  	runtime·printf("r7      %x\n", SIG_R7(info, ctxt));
  	runtime·printf("r8      %x\n", SIG_R8(info, ctxt));
  	runtime·printf("r9      %x\n", SIG_R9(info, ctxt));
  	runtime·printf("r10     %x\n", SIG_R10(info, ctxt));
  	runtime·printf("fp      %x\n", SIG_FP(info, ctxt));
  	runtime·printf("ip      %x\n", SIG_IP(info, ctxt));
  	runtime·printf("sp      %x\n", SIG_SP(info, ctxt));
  	runtime·printf("lr      %x\n", SIG_LR(info, ctxt));
  	runtime·printf("pc      %x\n", SIG_PC(info, ctxt));
  	runtime·printf("cpsr    %x\n", SIG_CPSR(info, ctxt));
  	runtime·printf("fault   %x\n", SIG_FAULT(info, ctxt));
  }
  
  void
  runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
  {
  	SigTab *t;
  	bool crash;
  
  	if(sig == SIGPROF) {
  		runtime·sigprof((uint8*)SIG_PC(info, ctxt), (uint8*)SIG_SP(info, ctxt), (uint8*)SIG_LR(info, ctxt), gp, g->m);
  		return;
  	}
  
  	t = &runtime·sigtab[sig];
  	if(SIG_CODE0(info, ctxt) != SI_USER && (t->flags & SigPanic)) {
  		// Make it look like a call to the signal func.
  		// Have to pass arguments out of band since
  		// augmenting the stack frame would break
  		// the unwinding code.
  		gp->sig = sig;
  		gp->sigcode0 = SIG_CODE0(info, ctxt);
  		gp->sigcode1 = SIG_FAULT(info, ctxt);
  		gp->sigpc = SIG_PC(info, ctxt);
  
  		// We arrange lr, and pc to pretend the panicking
  		// function calls sigpanic directly.
  		// Always save LR to stack so that panics in leaf
  		// functions are correctly handled. This smashes
  		// the stack frame but we're not going back there
  		// anyway.
  		SIG_SP(info, ctxt) -= 4;
  		*(uint32*)SIG_SP(info, ctxt) = SIG_LR(info, ctxt);
  		// Don't bother saving PC if it's zero, which is
  		// probably a call to a nil func: the old link register
  		// is more useful in the stack trace.
  		if(gp->sigpc != 0)
  			SIG_LR(info, ctxt) = gp->sigpc;
  		// In case we are panicking from external C code
  		SIG_R10(info, ctxt) = (uintptr)gp;
  		SIG_PC(info, ctxt) = (uintptr)runtime·sigpanic;
  		return;
  	}
  
  	if(SIG_CODE0(info, ctxt) == SI_USER || (t->flags & SigNotify))
  		if(runtime·sigsend(sig))
  			return;
  	if(t->flags & SigKill)
  		runtime·exit(2);
  	if(!(t->flags & SigThrow))
  		return;
  
  	g->m->throwing = 1;
  	g->m->caughtsig = gp;
  	if(runtime·panicking)	// traceback already printed
  		runtime·exit(2);
  	runtime·panicking = 1;
  
  	if(sig < 0 || sig >= NSIG)
  		runtime·printf("Signal %d\n", sig);
  	else
  		runtime·printf("%s\n", runtime·sigtab[sig].name);
  
  	runtime·printf("PC=%x\n", SIG_PC(info, ctxt));
  	if(g->m->lockedg != nil && g->m->ncgo > 0 && gp == g->m->g0) {
  		runtime·printf("signal arrived during cgo execution\n");
  		gp = g->m->lockedg;
  	}
  	runtime·printf("\n");
  
  	if(runtime·gotraceback(&crash)){
  		runtime·goroutineheader(gp);
  		runtime·traceback(SIG_PC(info, ctxt), SIG_SP(info, ctxt), SIG_LR(info, ctxt), gp);
  		runtime·tracebackothers(gp);
  		runtime·printf("\n");
  		runtime·dumpregs(info, ctxt);
  	}
  	
  	if(crash)
  		runtime·crash();
  
  	runtime·exit(2);
  }
  