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 #include <sys/time.h>
  10
  11 #include "go-assert.h"
  12 #include "go-panic.h"
  13 #include "go-signal.h"
  14
  15 #include "runtime.h"
  16
  17 #ifndef SA_RESTART
  18   #define SA_RESTART 0
  19 #endif
  20
  21 /* What to do for a signal.  */
  22
  23 struct sigtab
  24 {
  25   /* Signal number.  */
  26   int sig;
  27   /* Nonzero if the signal should be ignored.  */
  28   _Bool ignore;
  29   /* Nonzero if we should restart system calls.  */
  30   _Bool restart;
  31 };
  32
  33 /* What to do for signals.  */
  34
  35 static struct sigtab signals[] =
  36 {
  37   { SIGHUP, 0, 1 },
  38   { SIGINT, 0, 1 },
  39   { SIGALRM, 1, 1 },
  40   { SIGTERM, 0, 1 },
  41 #ifdef SIGBUS
  42   { SIGBUS, 0, 0 },
  43 #endif
  44 #ifdef SIGFPE
  45   { SIGFPE, 0, 0 },
  46 #endif
  47 #ifdef SIGUSR1
  48   { SIGUSR1, 1, 1 },
  49 #endif
  50 #ifdef SIGSEGV
  51   { SIGSEGV, 0, 0 },
  52 #endif
  53 #ifdef SIGUSR2
  54   { SIGUSR2, 1, 1 },
  55 #endif
  56 #ifdef SIGPIPE
  57   { SIGPIPE, 1, 0 },
  58 #endif
  59 #ifdef SIGCHLD
  60   { SIGCHLD, 1, 1 },
  61 #endif
  62 #ifdef SIGTSTP
  63   { SIGTSTP, 1, 1 },
  64 #endif
  65 #ifdef SIGTTIN
  66   { SIGTTIN, 1, 1 },
  67 #endif
  68 #ifdef SIGTTOU
  69   { SIGTTOU, 1, 1 },
  70 #endif
  71 #ifdef SIGURG
  72   { SIGURG, 1, 1 },
  73 #endif
  74 #ifdef SIGXCPU
  75   { SIGXCPU, 1, 1 },
  76 #endif
  77 #ifdef SIGXFSZ
  78   { SIGXFSZ, 1, 1 },
  79 #endif
  80 #ifdef SIGVTARLM
  81   { SIGVTALRM, 1, 1 },
  82 #endif
  83 #ifdef SIGWINCH
  84   { SIGWINCH, 1, 1 },
  85 #endif
  86 #ifdef SIGIO
  87   { SIGIO, 1, 1 },
  88 #endif
  89 #ifdef SIGPWR
  90   { SIGPWR, 1, 1 },
  91 #endif
  92   { -1, 0, 0 }
  93 };
  94
  95 /* The Go signal handler.  */
  96
  97 static void
  98 sighandler (int sig)
  99 {
 100   const char *msg;
 101   int i;
 102
 103   if (sig == SIGPROF)
 104     {
 105       /* FIXME.  */
 106       runtime_sigprof (0, 0, nil);
 107       return;
 108     }
 109
 110   /* FIXME: Should check siginfo for more information when
 111      available.  */
 112   msg = NULL;
 113   switch (sig)
 114     {
 115 #ifdef SIGBUS
 116     case SIGBUS:
 117       msg = "invalid memory address or nil pointer dereference";
 118       break;
 119 #endif
 120
 121 #ifdef SIGFPE
 122     case SIGFPE:
 123       msg = "integer divide by zero or floating point error";
 124       break;
 125 #endif
 126
 127 #ifdef SIGSEGV
 128     case SIGSEGV:
 129       msg = "invalid memory address or nil pointer dereference";
 130       break;
 131 #endif
 132
 133     default:
 134       break;
 135     }
 136
 137   if (msg != NULL)
 138     {
 139       sigset_t clear;
 140
 141       if (__sync_bool_compare_and_swap (&m->mallocing, 1, 1))
 142         {
 143           fprintf (stderr, "caught signal while mallocing: %s\n", msg);
 144           __go_assert (0);
 145         }
 146
 147       /* The signal handler blocked signals; unblock them.  */
 148       i = sigfillset (&clear);
 149       __go_assert (i == 0);
 150       i = sigprocmask (SIG_UNBLOCK, &clear, NULL);
 151       __go_assert (i == 0);
 152
 153       __go_panic_msg (msg);
 154     }
 155
 156   if (__go_sigsend (sig))
 157     return;
 158   for (i = 0; signals[i].sig != -1; ++i)
 159     {
 160       if (signals[i].sig == sig)
 161         {
 162           struct sigaction sa;
 163
 164           if (signals[i].ignore)
 165             return;
 166
 167           memset (&sa, 0, sizeof sa);
 168
 169           sa.sa_handler = SIG_DFL;
 170
 171           i = sigemptyset (&sa.sa_mask);
 172           __go_assert (i == 0);
 173
 174           if (sigaction (sig, &sa, NULL) != 0)
 175             abort ();
 176
 177           raise (sig);
 178           exit (2);
 179         }
 180     }
 181   abort ();
 182 }
 183
 184 /* Initialize signal handling for Go.  This is called when the program
 185    starts.  */
 186
 187 void
 188 __initsig ()
 189 {
 190   struct sigaction sa;
 191   int i;
 192
 193   siginit ();
 194
 195   memset (&sa, 0, sizeof sa);
 196
 197   sa.sa_handler = sighandler;
 198
 199   i = sigfillset (&sa.sa_mask);
 200   __go_assert (i == 0);
 201
 202   for (i = 0; signals[i].sig != -1; ++i)
 203     {
 204       sa.sa_flags = signals[i].restart ? SA_RESTART : 0;
 205       if (sigaction (signals[i].sig, &sa, NULL) != 0)
 206         __go_assert (0);
 207     }
 208 }
 209
 210 void
 211 runtime_resetcpuprofiler(int32 hz)
 212 {
 213   struct itimerval it;
 214   struct sigaction sa;
 215   int i;
 216
 217   memset (&it, 0, sizeof it);
 218
 219   memset (&sa, 0, sizeof sa);
 220   i = sigfillset (&sa.sa_mask);
 221   __go_assert (i == 0);
 222
 223   if (hz == 0)
 224     {
 225       i = setitimer (ITIMER_PROF, &it, NULL);
 226       __go_assert (i == 0);
 227
 228       sa.sa_handler = SIG_IGN;
 229       i = sigaction (SIGPROF, &sa, NULL);
 230       __go_assert (i == 0);
 231     }
 232   else
 233     {
 234       sa.sa_handler = sighandler;
 235       sa.sa_flags = SA_RESTART;
 236       i = sigaction (SIGPROF, &sa, NULL);
 237       __go_assert (i == 0);
 238
 239       it.it_interval.tv_sec = 0;
 240       it.it_interval.tv_usec = 1000000 / hz;
 241       it.it_value = it.it_interval;
 242       i = setitimer (ITIMER_PROF, &it, NULL);
 243       __go_assert (i == 0);
 244     }
 245
 246   m->profilehz = hz;
 247 }