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) 2002-2023, 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 #ifndef IN_RTS
  33 #include "config.h"
  34 #include "system.h"
  35 #endif
  36
  37 /* Services to intercept Ctrl-C */
  38
  39 /* __gnat_install_int_handler will install the specified handler.
  40    If called for the first time, it will also save the original handler */
  41 void __gnat_install_int_handler (void (*) (void));
  42
  43 /* __gnat_uninstall_int_handler will reinstall the original handler */
  44 void __gnat_uninstall_int_handler (void);
  45
  46 /* POSIX implementation */
  47
  48 #if (defined (__unix__) || defined (_AIX) || defined (__APPLE__)) \
  49  || defined (VMS) && !defined (__vxworks)
  50
  51 #ifdef VMS
  52 /* On VMS _gnat_handle_vms_condition gets control first, and it has to
  53    resignal the Ctrl/C in order for sigaction to gain control and execute
  54    the user handler routine, but in doing so propagates the condition
  55    causing the program to terminate.   So instead we install a dummy handler
  56    routine and put the real user handler in a special global variable so
  57    that __gnat_handle_vms_condition  can declare an AST to asynchronously
  58    execute the Ctrl/C user handler at some future time and allow
  59    __gnat_handle_vms_condition to return and not be held up waiting for
  60    the potentially unbounded time required to execute the Crtl/C handler.  */
  61 void
  62 dummy_handler () {}
  63
  64 /* Lives in init.c.  */
  65 extern void (*__gnat_ctrl_c_handler) (void);
  66 #endif
  67
  68 #include <signal.h>
  69
  70 void (*sigint_intercepted) (void) = 0;
  71
  72 struct sigaction original_act;
  73
  74 static void
  75 __gnat_int_handler (int sig __attribute__ ((unused)))
  76 {
  77   if (sigint_intercepted != 0)
  78     sigint_intercepted ();
  79 }
  80
  81 /* Install handler and save original handler. */
  82
  83 void
  84 __gnat_install_int_handler (void (*proc) (void))
  85 {
  86   struct sigaction act;
  87
  88   if (sigint_intercepted == 0)
  89     {
  90       act.sa_handler = __gnat_int_handler;
  91 #if defined (__Lynx__) || defined (VMS) || defined(__DJGPP__)
  92       /* LynxOS, VMS and DJGPP do not support SA_RESTART. */
  93       act.sa_flags = 0;
  94 #else
  95       act.sa_flags = SA_RESTART;
  96 #endif
  97       sigemptyset (&act.sa_mask);
  98       sigaction (SIGINT, &act, &original_act);
  99     }
 100
 101 #ifdef VMS
 102   sigint_intercepted = &dummy_handler;
 103   __gnat_ctrl_c_handler = proc;
 104 #else
 105   sigint_intercepted = proc;
 106 #endif
 107 }
 108
 109 /* Restore original handler */
 110
 111 void
 112 __gnat_uninstall_int_handler (void)
 113 {
 114  if (sigint_intercepted != 0)
 115    {
 116      sigaction (SIGINT, &original_act, 0);
 117      sigint_intercepted = 0;
 118    }
 119 #ifdef VMS
 120   if (__gnat_ctrl_c_handler)
 121     __gnat_ctrl_c_handler = 0;
 122 #endif
 123 }
 124
 125 /* Windows implementation */
 126
 127 #elif defined (__MINGW32__)
 128
 129 #define WIN32_LEAN_AND_MEAN
 130 #include "mingw32.h"
 131 #include <windows.h>
 132
 133 void (*sigint_intercepted) (void) = NULL;
 134
 135 static BOOL WINAPI
 136 __gnat_int_handler  (DWORD dwCtrlType)
 137 {
 138   switch (dwCtrlType)
 139     {
 140     case CTRL_C_EVENT:
 141     case CTRL_BREAK_EVENT:
 142       if (sigint_intercepted != 0)
 143         {
 144           sigint_intercepted ();
 145           return TRUE;
 146         }
 147       break;
 148
 149     case CTRL_CLOSE_EVENT:
 150     case CTRL_LOGOFF_EVENT:
 151     case CTRL_SHUTDOWN_EVENT:
 152       break;
 153     }
 154
 155   return FALSE;
 156 }
 157
 158 void
 159 __gnat_install_int_handler (void (*proc) (void))
 160 {
 161   if (sigint_intercepted == NULL)
 162     SetConsoleCtrlHandler (__gnat_int_handler, TRUE);
 163
 164   sigint_intercepted = proc;
 165 }
 166
 167 void
 168 __gnat_uninstall_int_handler (void)
 169 {
 170   if (sigint_intercepted != NULL)
 171     SetConsoleCtrlHandler (__gnat_int_handler, FALSE);
 172
 173   sigint_intercepted = NULL;
 174 }
 175
 176 /* Default implementation: do nothing */
 177
 178 #else
 179
 180 void
 181 __gnat_install_int_handler (void (*proc) (void) __attribute__ ((unused)))
 182 {
 183 }
 184
 185 void
 186 __gnat_uninstall_int_handler (void)
 187 {
 188 }
 189 #endif