libgo/runtime/go-signal.c

   1 /* go-signal.c -- signal handling for Go.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include <signal.h>
   8 #include <stdlib.h>
   9
  10 #include "go-assert.h"
  11 #include "go-panic.h"
  12 #include "go-signal.h"
  13
  14 #include "runtime.h"
  15
  16 #undef int
  17
  18 #ifndef SA_ONSTACK
  19 #define SA_ONSTACK 0
  20 #endif
  21
  22 /* What to do for a signal.  */
  23
  24 struct sigtab
  25 {
  26   /* Signal number.  */
  27   int sig;
  28   /* Nonzero if the signal should be ignored.  */
  29   _Bool ignore;
  30 };
  31
  32 /* What to do for signals.  */
  33
  34 static struct sigtab signals[] =
  35 {
  36   { SIGHUP, 0 },
  37   { SIGINT, 0 },
  38   { SIGALRM, 1 },
  39   { SIGTERM, 0 },
  40 #ifdef SIGBUS
  41   { SIGBUS, 0 },
  42 #endif
  43 #ifdef SIGFPE
  44   { SIGFPE, 0 },
  45 #endif
  46 #ifdef SIGUSR1
  47   { SIGUSR1, 1 },
  48 #endif
  49 #ifdef SIGSEGV
  50   { SIGSEGV, 0 },
  51 #endif
  52 #ifdef SIGUSR2
  53   { SIGUSR2, 1 },
  54 #endif
  55 #ifdef SIGPIPE
  56   { SIGPIPE, 1 },
  57 #endif
  58 #ifdef SIGCHLD
  59   { SIGCHLD, 1 },
  60 #endif
  61 #ifdef SIGTSTP
  62   { SIGTSTP, 1 },
  63 #endif
  64 #ifdef SIGTTIN
  65   { SIGTTIN, 1 },
  66 #endif
  67 #ifdef SIGTTOU
  68   { SIGTTOU, 1 },
  69 #endif
  70 #ifdef SIGURG
  71   { SIGURG, 1 },
  72 #endif
  73 #ifdef SIGXCPU
  74   { SIGXCPU, 1 },
  75 #endif
  76 #ifdef SIGXFSZ
  77   { SIGXFSZ, 1 },
  78 #endif
  79 #ifdef SIGVTARLM
  80   { SIGVTALRM, 1 },
  81 #endif
  82 #ifdef SIGPROF
  83   { SIGPROF, 1 },
  84 #endif
  85 #ifdef SIGWINCH
  86   { SIGWINCH, 1 },
  87 #endif
  88 #ifdef SIGIO
  89   { SIGIO, 1 },
  90 #endif
  91 #ifdef SIGPWR
  92   { SIGPWR, 1 },
  93 #endif
  94   { -1, 0 }
  95 };
  96
  97 /* The Go signal handler.  */
  98
  99 static void
 100 sighandler (int sig)
 101 {
 102   const char *msg;
 103   int i;
 104
 105   /* FIXME: Should check siginfo for more information when
 106      available.  */
 107   msg = NULL;
 108   switch (sig)
 109     {
 110 #ifdef SIGBUS
 111     case SIGBUS:
 112       msg = "invalid memory address or nil pointer dereference";
 113       break;
 114 #endif
 115
 116 #ifdef SIGFPE
 117     case SIGFPE:
 118       msg = "integer divide by zero or floating point error";
 119       break;
 120 #endif
 121
 122 #ifdef SIGSEGV
 123     case SIGSEGV:
 124       msg = "invalid memory address or nil pointer dereference";
 125       break;
 126 #endif
 127
 128     default:
 129       break;
 130     }
 131
 132   if (msg != NULL)
 133     {
 134       sigset_t clear;
 135
 136       if (__sync_bool_compare_and_swap (&m->mallocing, 1, 1))
 137         {
 138           fprintf (stderr, "caught signal while mallocing: %s\n", msg);
 139           __go_assert (0);
 140         }
 141
 142       /* The signal handler blocked signals; unblock them.  */
 143       i = sigfillset (&clear);
 144       __go_assert (i == 0);
 145       i = sigprocmask (SIG_UNBLOCK, &clear, NULL);
 146       __go_assert (i == 0);
 147
 148       __go_panic_msg (msg);
 149     }
 150
 151   if (__go_sigsend (sig))
 152     return;
 153   for (i = 0; signals[i].sig != -1; ++i)
 154     {
 155       if (signals[i].sig == sig)
 156         {
 157           struct sigaction sa;
 158
 159           if (signals[i].ignore)
 160             return;
 161
 162           memset (&sa, 0, sizeof sa);
 163
 164           sa.sa_handler = SIG_DFL;
 165
 166           i = sigemptyset (&sa.sa_mask);
 167           __go_assert (i == 0);
 168
 169           if (sigaction (sig, &sa, NULL) != 0)
 170             abort ();
 171
 172           raise (sig);
 173           exit (2);
 174         }
 175     }
 176   abort ();
 177 }
 178
 179 /* Initialize signal handling for Go.  This is called when the program
 180    starts.  */
 181
 182 void
 183 __initsig ()
 184 {
 185   struct sigaction sa;
 186   int i;
 187
 188   siginit ();
 189
 190   memset (&sa, 0, sizeof sa);
 191
 192   sa.sa_handler = sighandler;
 193
 194   i = sigfillset (&sa.sa_mask);
 195   __go_assert (i == 0);
 196
 197   for (i = 0; signals[i].sig != -1; ++i)
 198     if (sigaction (signals[i].sig, &sa, NULL) != 0)
 199       __go_assert (0);
 200 }