libgo/runtime/panic.c

   1 // Copyright 2012 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 #include "runtime.h"
   6 #include "malloc.h"
   7 #include "go-defer.h"
   8 #include "go-panic.h"
   9
  10 // Code related to defer, panic and recover.
  11
  12 uint32 runtime_panicking;
  13 static Lock paniclk;
  14
  15 // Run all deferred functions for the current goroutine.
  16 static void
  17 rundefer(void)
  18 {
  19         G *g;
  20         Defer *d;
  21
  22         g = runtime_g();
  23         while((d = g->defer) != nil) {
  24                 void (*pfn)(void*);
  25
  26                 g->defer = d->__next;
  27                 pfn = d->__pfn;
  28                 d->__pfn = nil;
  29                 if (pfn != nil)
  30                         (*pfn)(d->__arg);
  31                 runtime_free(d);
  32         }
  33 }
  34
  35 void
  36 runtime_startpanic(void)
  37 {
  38         M *m;
  39
  40         m = runtime_m();
  41         if(runtime_mheap == 0 || runtime_mheap->cachealloc.size == 0) { // very early
  42                 runtime_printf("runtime: panic before malloc heap initialized\n");
  43                 m->mallocing = 1; // tell rest of panic not to try to malloc
  44         } else if(m->mcache == nil) // can happen if called from signal handler or throw
  45                 m->mcache = runtime_allocmcache();
  46         if(m->dying) {
  47                 runtime_printf("panic during panic\n");
  48                 runtime_exit(3);
  49         }
  50         m->dying = 1;
  51         runtime_xadd(&runtime_panicking, 1);
  52         runtime_lock(&paniclk);
  53 }
  54
  55 void
  56 runtime_dopanic(int32 unused __attribute__ ((unused)))
  57 {
  58         G *g;
  59         static bool didothers;
  60         bool crash;
  61
  62         g = runtime_g();
  63         if(g->sig != 0)
  64                 runtime_printf("[signal %x code=%p addr=%p]\n",
  65                                g->sig, (void*)g->sigcode0, (void*)g->sigcode1);
  66
  67         if(runtime_gotraceback(&crash)){
  68                 if(g != runtime_m()->g0) {
  69                         runtime_printf("\n");
  70                         runtime_goroutineheader(g);
  71                         runtime_traceback();
  72                         runtime_goroutinetrailer(g);
  73                 }
  74                 if(!didothers) {
  75                         didothers = true;
  76                         runtime_tracebackothers(g);
  77                 }
  78         }
  79         runtime_unlock(&paniclk);
  80         if(runtime_xadd(&runtime_panicking, -1) != 0) {
  81                 // Some other m is panicking too.
  82                 // Let it print what it needs to print.
  83                 // Wait forever without chewing up cpu.
  84                 // It will exit when it's done.
  85                 static Lock deadlock;
  86                 runtime_lock(&deadlock);
  87                 runtime_lock(&deadlock);
  88         }
  89
  90         if(crash)
  91                 runtime_crash();
  92
  93         runtime_exit(2);
  94 }
  95
  96 void
  97 runtime_throw(const char *s)
  98 {
  99         M *mp;
 100
 101         mp = runtime_m();
 102         if(mp->throwing == 0)
 103                 mp->throwing = 1;
 104         runtime_startpanic();
 105         runtime_printf("fatal error: %s\n", s);
 106         runtime_dopanic(0);
 107         *(int32*)0 = 0; // not reached
 108         runtime_exit(1);        // even more not reached
 109 }
 110
 111 void
 112 runtime_panicstring(const char *s)
 113 {
 114         Eface err;
 115
 116         if(runtime_m()->gcing) {
 117                 runtime_printf("panic: %s\n", s);
 118                 runtime_throw("panic during gc");
 119         }
 120         runtime_newErrorString(runtime_gostringnocopy((const byte*)s), &err);
 121         runtime_panic(err);
 122 }
 123
 124 void runtime_Goexit (void) __asm__ (GOSYM_PREFIX "runtime.Goexit");
 125
 126 void
 127 runtime_Goexit(void)
 128 {
 129         rundefer();
 130         runtime_goexit();
 131 }