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// Copyright 2012 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 "malloc.h"
#include "go-defer.h"
#include "go-panic.h"
// Code related to defer, panic and recover.
uint32 runtime_panicking;
static Lock paniclk;
// Allocate a Defer, usually using per-P pool.
// Each defer must be released with freedefer.
Defer*
runtime_newdefer()
{
Defer *d;
P *p;
d = nil;
p = runtime_m()->p;
d = p->deferpool;
if(d)
p->deferpool = d->__next;
if(d == nil) {
// deferpool is empty
d = runtime_malloc(sizeof(Defer));
}
return d;
}
// Free the given defer.
// The defer cannot be used after this call.
void
runtime_freedefer(Defer *d)
{
P *p;
if(d->__special)
return;
p = runtime_m()->p;
d->__next = p->deferpool;
p->deferpool = d;
// No need to wipe out pointers in argp/pc/fn/args,
// because we empty the pool before GC.
}
// Run all deferred functions for the current goroutine.
// This is noinline for go_can_recover.
static void __go_rundefer (void) __attribute__ ((noinline));
static void
__go_rundefer(void)
{
G *g;
Defer *d;
g = runtime_g();
while((d = g->defer) != nil) {
void (*pfn)(void*);
g->defer = d->__next;
pfn = d->__pfn;
d->__pfn = nil;
if (pfn != nil)
(*pfn)(d->__arg);
runtime_freedefer(d);
}
}
void
runtime_startpanic(void)
{
M *m;
m = runtime_m();
if(runtime_mheap.cachealloc.size == 0) { // very early
runtime_printf("runtime: panic before malloc heap initialized\n");
m->mallocing = 1; // tell rest of panic not to try to malloc
} else if(m->mcache == nil) // can happen if called from signal handler or throw
m->mcache = runtime_allocmcache();
switch(m->dying) {
case 0:
m->dying = 1;
if(runtime_g() != nil)
runtime_g()->writebuf = nil;
runtime_xadd(&runtime_panicking, 1);
runtime_lock(&paniclk);
if(runtime_debug.schedtrace > 0 || runtime_debug.scheddetail > 0)
runtime_schedtrace(true);
runtime_freezetheworld();
return;
case 1:
// Something failed while panicing, probably the print of the
// argument to panic(). Just print a stack trace and exit.
m->dying = 2;
runtime_printf("panic during panic\n");
runtime_dopanic(0);
runtime_exit(3);
case 2:
// This is a genuine bug in the runtime, we couldn't even
// print the stack trace successfully.
m->dying = 3;
runtime_printf("stack trace unavailable\n");
runtime_exit(4);
default:
// Can't even print! Just exit.
runtime_exit(5);
}
}
void
runtime_dopanic(int32 unused __attribute__ ((unused)))
{
G *g;
static bool didothers;
bool crash;
int32 t;
g = runtime_g();
if(g->sig != 0)
runtime_printf("[signal %x code=%p addr=%p]\n",
g->sig, (void*)g->sigcode0, (void*)g->sigcode1);
if((t = runtime_gotraceback(&crash)) > 0){
if(g != runtime_m()->g0) {
runtime_printf("\n");
runtime_goroutineheader(g);
runtime_traceback();
runtime_printcreatedby(g);
} else if(t >= 2 || runtime_m()->throwing > 0) {
runtime_printf("\nruntime stack:\n");
runtime_traceback();
}
if(!didothers) {
didothers = true;
runtime_tracebackothers(g);
}
}
runtime_unlock(&paniclk);
if(runtime_xadd(&runtime_panicking, -1) != 0) {
// Some other m is panicking too.
// Let it print what it needs to print.
// Wait forever without chewing up cpu.
// It will exit when it's done.
static Lock deadlock;
runtime_lock(&deadlock);
runtime_lock(&deadlock);
}
if(crash)
runtime_crash();
runtime_exit(2);
}
bool
runtime_canpanic(G *gp)
{
M *m = runtime_m();
byte g;
USED(&g); // don't use global g, it points to gsignal
// Is it okay for gp to panic instead of crashing the program?
// Yes, as long as it is running Go code, not runtime code,
// and not stuck in a system call.
if(gp == nil || gp != m->curg)
return false;
if(m->locks-m->softfloat != 0 || m->mallocing != 0 || m->throwing != 0 || m->gcing != 0 || m->dying != 0)
return false;
if(gp->status != Grunning)
return false;
#ifdef GOOS_windows
if(m->libcallsp != 0)
return false;
#endif
return true;
}
void
runtime_throw(const char *s)
{
M *mp;
mp = runtime_m();
if(mp->throwing == 0)
mp->throwing = 1;
runtime_startpanic();
runtime_printf("fatal error: %s\n", s);
runtime_dopanic(0);
*(int32*)0 = 0; // not reached
runtime_exit(1); // even more not reached
}
void
runtime_panicstring(const char *s)
{
Eface err;
if(runtime_m()->mallocing) {
runtime_printf("panic: %s\n", s);
runtime_throw("panic during malloc");
}
if(runtime_m()->gcing) {
runtime_printf("panic: %s\n", s);
runtime_throw("panic during gc");
}
if(runtime_m()->locks) {
runtime_printf("panic: %s\n", s);
runtime_throw("panic holding locks");
}
runtime_newErrorCString(s, &err);
runtime_panic(err);
}
void runtime_Goexit (void) __asm__ (GOSYM_PREFIX "runtime.Goexit");
void
runtime_Goexit(void)
{
__go_rundefer();
runtime_goexit();
}
void
runtime_panicdivide(void)
{
runtime_panicstring("integer divide by zero");
}
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