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// 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 amd64 amd64p32
// +build darwin dragonfly freebsd linux nacl netbsd openbsd solaris
#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("rax %X\n", SIG_RAX(info, ctxt));
runtime·printf("rbx %X\n", SIG_RBX(info, ctxt));
runtime·printf("rcx %X\n", SIG_RCX(info, ctxt));
runtime·printf("rdx %X\n", SIG_RDX(info, ctxt));
runtime·printf("rdi %X\n", SIG_RDI(info, ctxt));
runtime·printf("rsi %X\n", SIG_RSI(info, ctxt));
runtime·printf("rbp %X\n", SIG_RBP(info, ctxt));
runtime·printf("rsp %X\n", SIG_RSP(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("r11 %X\n", SIG_R11(info, ctxt));
runtime·printf("r12 %X\n", SIG_R12(info, ctxt));
runtime·printf("r13 %X\n", SIG_R13(info, ctxt));
runtime·printf("r14 %X\n", SIG_R14(info, ctxt));
runtime·printf("r15 %X\n", SIG_R15(info, ctxt));
runtime·printf("rip %X\n", SIG_RIP(info, ctxt));
runtime·printf("rflags %X\n", SIG_RFLAGS(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_RIP(info, ctxt), (byte*)SIG_RSP(info, ctxt), nil, gp, m);
return;
}
#ifdef GOOS_darwin
// x86-64 has 48-bit virtual addresses. The top 16 bits must echo bit 47.
// The hardware delivers a different kind of fault for a malformed address
// than it does for an attempt to access a valid but unmapped address.
// OS X 10.9.2 mishandles the malformed address case, making it look like
// a user-generated signal (like someone ran kill -SEGV ourpid).
// We pass user-generated signals to os/signal, or else ignore them.
// Doing that here - and returning to the faulting code - results in an
// infinite loop. It appears the best we can do is rewrite what the kernel
// delivers into something more like the truth. The address used below
// has very little chance of being the one that caused the fault, but it is
// malformed, it is clearly not a real pointer, and if it does get printed
// in real life, people will probably search for it and find this code.
// There are no Google hits for b01dfacedebac1e or 0xb01dfacedebac1e
// as I type this comment.
if(sig == SIGSEGV && SIG_CODE0(info, ctxt) == SI_USER) {
SIG_CODE0(info, ctxt) = SI_USER+1;
info->si_addr = (void*)(uintptr)0xb01dfacedebac1eULL;
}
#endif
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_RIP(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]&0xF0) == 0x40) // 64-bit REX prefix
pc++;
else 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 rip != 0.
// If rip == 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_RIP(info, ctxt) != 0) {
sp = (uintptr*)SIG_RSP(info, ctxt);
if(sizeof(uintreg) > sizeof(uintptr))
*--sp = 0;
*--sp = SIG_RIP(info, ctxt);
SIG_RSP(info, ctxt) = (uintptr)sp;
}
SIG_RIP(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_RIP(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_RIP(info, ctxt), SIG_RSP(info, ctxt), 0, gp);
runtime·tracebackothers(gp);
runtime·printf("\n");
runtime·dumpregs(info, ctxt);
}
if(crash)
runtime·crash();
runtime·exit(2);
}
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