gcc/ada/ctrl_c.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                               C T R L _ C                                *
   6  *                                                                          *
   7  *                          C Implementation File                           *
   8  *                                                                          *
   9  *        Copyright (C) 2002-2018, Free Software Foundation, Inc.           *
  10  *                                                                          *
  11  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  12  * terms of the  GNU General Public License as published  by the Free Soft- *
  13  * ware  Foundation;  either version 3,  or (at your option) any later ver- *
  14  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  15  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  16  * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
  17  *                                                                          *
  18  * As a special exception under Section 7 of GPL version 3, you are granted *
  19  * additional permissions described in the GCC Runtime Library Exception,   *
  20  * version 3.1, as published by the Free Software Foundation.               *
  21  *                                                                          *
  22  * You should have received a copy of the GNU General Public License and    *
  23  * a copy of the GCC Runtime Library Exception along with this program;     *
  24  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    *
  25  * <http://www.gnu.org/licenses/>.                                          *
  26  *                                                                          *
  27  * GNAT was originally developed  by the GNAT team at  New York University. *
  28  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  29  *                                                                          *
  30  ****************************************************************************/
  31
  32 #ifdef IN_RTS
  33 #include "tconfig.h"
  34 #include "tsystem.h"
  35 #include <sys/stat.h>
  36 #else
  37 #include "config.h"
  38 #include "system.h"
  39 #endif
  40
  41 /* Services to intercept Ctrl-C */
  42
  43 /* __gnat_install_int_handler will install the specified handler.
  44    If called for the first time, it will also save the original handler */
  45 void __gnat_install_int_handler (void (*) (void));
  46
  47 /* __gnat_uninstall_int_handler will reinstall the original handler */
  48 void __gnat_uninstall_int_handler (void);
  49
  50 /* POSIX implementation */
  51
  52 #if (defined (__unix__) || defined (_AIX) || defined (__APPLE__)) \
  53  || defined (VMS) && !defined (__vxworks)
  54
  55 #ifdef VMS
  56 /* On VMS _gnat_handle_vms_condition gets control first, and it has to
  57    resignal the Ctrl/C in order for sigaction to gain control and execute
  58    the user handler routine, but in doing so propagates the condition
  59    causing the program to terminate.   So instead we install a dummy handler
  60    routine and put the real user handler in a special global variable so
  61    that __gnat_handle_vms_condition  can declare an AST to asynchronously
  62    execute the Ctrl/C user handler at some future time and allow
  63    __gnat_handle_vms_condition to return and not be held up waiting for
  64    the potentially unbounded time required to execute the Crtl/C handler.  */
  65 void
  66 dummy_handler () {}
  67
  68 /* Lives in init.c.  */
  69 extern void (*__gnat_ctrl_c_handler) (void);
  70 #endif
  71
  72 #include <signal.h>
  73
  74 void (*sigint_intercepted) (void) = 0;
  75
  76 struct sigaction original_act;
  77
  78 static void
  79 __gnat_int_handler (int sig __attribute__ ((unused)))
  80 {
  81   if (sigint_intercepted != 0)
  82     sigint_intercepted ();
  83 }
  84
  85 /* Install handler and save original handler. */
  86
  87 void
  88 __gnat_install_int_handler (void (*proc) (void))
  89 {
  90   struct sigaction act;
  91
  92   if (sigint_intercepted == 0)
  93     {
  94       act.sa_handler = __gnat_int_handler;
  95 #if defined (__Lynx__) || defined (VMS) || defined(__DJGPP__)
  96       /* LynxOS, VMS and DJGPP do not support SA_RESTART. */
  97       act.sa_flags = 0;
  98 #else
  99       act.sa_flags = SA_RESTART;
 100 #endif
 101       sigemptyset (&act.sa_mask);
 102       sigaction (SIGINT, &act, &original_act);
 103     }
 104
 105 #ifdef VMS
 106   sigint_intercepted = &dummy_handler;
 107   __gnat_ctrl_c_handler = proc;
 108 #else
 109   sigint_intercepted = proc;
 110 #endif
 111 }
 112
 113 /* Restore original handler */
 114
 115 void
 116 __gnat_uninstall_int_handler (void)
 117 {
 118  if (sigint_intercepted != 0)
 119    {
 120      sigaction (SIGINT, &original_act, 0);
 121      sigint_intercepted = 0;
 122    }
 123 #ifdef VMS
 124   if (__gnat_ctrl_c_handler)
 125     __gnat_ctrl_c_handler = 0;
 126 #endif
 127 }
 128
 129 /* Windows implementation */
 130
 131 #elif defined (__MINGW32__)
 132
 133 #include "mingw32.h"
 134 #include <windows.h>
 135
 136 void (*sigint_intercepted) (void) = NULL;
 137
 138 static BOOL WINAPI
 139 __gnat_int_handler  (DWORD dwCtrlType)
 140 {
 141   switch (dwCtrlType)
 142     {
 143     case CTRL_C_EVENT:
 144     case CTRL_BREAK_EVENT:
 145       if (sigint_intercepted != 0)
 146         {
 147           sigint_intercepted ();
 148           return TRUE;
 149         }
 150       break;
 151
 152     case CTRL_CLOSE_EVENT:
 153     case CTRL_LOGOFF_EVENT:
 154     case CTRL_SHUTDOWN_EVENT:
 155       break;
 156     }
 157
 158   return FALSE;
 159 }
 160
 161 void
 162 __gnat_install_int_handler (void (*proc) (void))
 163 {
 164   if (sigint_intercepted == NULL)
 165     SetConsoleCtrlHandler (__gnat_int_handler, TRUE);
 166
 167   sigint_intercepted = proc;
 168 }
 169
 170 void
 171 __gnat_uninstall_int_handler (void)
 172 {
 173   if (sigint_intercepted != NULL)
 174     SetConsoleCtrlHandler (__gnat_int_handler, FALSE);
 175
 176   sigint_intercepted = NULL;
 177 }
 178
 179 /* Default implementation: do nothing */
 180
 181 #else
 182
 183 void
 184 __gnat_install_int_handler (void (*proc) (void) __attribute__ ((unused)))
 185 {
 186 }
 187
 188 void
 189 __gnat_uninstall_int_handler (void)
 190 {
 191 }
 192 #endif