root/src/pkg/runtime/signal_386.c

DEFINITIONS

1. runtime·dumpregs
2. runtime·sighandler

// Copyright 2013 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("eax     %x\n", SIG_EAX(info, ctxt));
        runtime·printf("ebx     %x\n", SIG_EBX(info, ctxt));
        runtime·printf("ecx     %x\n", SIG_ECX(info, ctxt));
        runtime·printf("edx     %x\n", SIG_EDX(info, ctxt));
        runtime·printf("edi     %x\n", SIG_EDI(info, ctxt));
        runtime·printf("esi     %x\n", SIG_ESI(info, ctxt));
        runtime·printf("ebp     %x\n", SIG_EBP(info, ctxt));
        runtime·printf("esp     %x\n", SIG_ESP(info, ctxt));
        runtime·printf("eip     %x\n", SIG_EIP(info, ctxt));
        runtime·printf("eflags  %x\n", SIG_EFLAGS(info, ctxt));
        runtime·printf("cs      %x\n", SIG_CS(info, ctxt));
        runtime·printf("fs      %x\n", SIG_FS(info, ctxt));
        runtime·printf("gs      %x\n", SIG_GS(info, ctxt));
}

void
runtime·sighandler(int32 sig, Siginfo *info, void *ctxt, G *gp)
{
        uintptr *sp;
        SigTab *t;
        bool crash;

        if(sig == SIGPROF) {
                runtime·sigprof((byte*)SIG_EIP(info, ctxt), (byte*)SIG_ESP(info, ctxt), nil, gp, 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_CODE1(info, ctxt);
                gp->sigpc = SIG_EIP(info, ctxt);

#ifdef GOOS_darwin
                // Work around Leopard bug that doesn't set FPE_INTDIV.
                // Look at instruction to see if it is a divide.
                // Not necessary in Snow Leopard (si_code will be != 0).
                if(sig == SIGFPE && gp->sigcode0 == 0) {
                        byte *pc;
                        pc = (byte*)gp->sigpc;
                        if(pc[0] == 0x66)       // 16-bit instruction prefix
                                pc++;
                        if(pc[0] == 0xF6 || pc[0] == 0xF7)
                                gp->sigcode0 = FPE_INTDIV;
                }
#endif

                // Only push runtime·sigpanic if eip != 0.
                // If eip == 0, probably panicked because of a
                // call to a nil func.  Not pushing that onto sp will
                // make the trace look like a call to runtime·sigpanic instead.
                // (Otherwise the trace will end at runtime·sigpanic and we
                // won't get to see who faulted.)
                if(SIG_EIP(info, ctxt) != 0) {
                        sp = (uintptr*)SIG_ESP(info, ctxt);
                        *--sp = SIG_EIP(info, ctxt);
                        SIG_ESP(info, ctxt) = (uintptr)sp;
                }
                SIG_EIP(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;

        m->throwing = 1;
        m->caughtsig = gp;
        runtime·startpanic();

        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_EIP(info, ctxt));
        if(m->lockedg != nil && m->ncgo > 0 && gp == m->g0) {
                runtime·printf("signal arrived during cgo execution\n");
                gp = m->lockedg;
        }       
        runtime·printf("\n");

        if(runtime·gotraceback(&crash)){
                runtime·goroutineheader(gp);
                runtime·traceback(SIG_EIP(info, ctxt), SIG_ESP(info, ctxt), 0, gp);
                runtime·tracebackothers(gp);
                runtime·printf("\n");
                runtime·dumpregs(info, ctxt);
        }
        
        if(crash)
                runtime·crash();

        runtime·exit(2);
}