gdb/common/signals-state-save-restore.c

   1 /* Copyright (C) 2016-2017 Free Software Foundation, Inc.
   2
   3    This file is part of GDB.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "common-defs.h"
  19 #include "signals-state-save-restore.h"
  20
  21 #include <signal.h>
  22
  23 /* The original signal actions and mask.  */
  24
  25 #ifdef HAVE_SIGACTION
  26 static struct sigaction original_signal_actions[NSIG];
  27
  28 /* Note that we use sigprocmask without worrying about threads because
  29    the save/restore functions are called either from main, or after a
  30    fork.  In both cases, we know the calling process is single
  31    threaded.  */
  32 static sigset_t original_signal_mask;
  33 #endif
  34
  35 /* See signals-state-save-restore.h.   */
  36
  37 void
  38 save_original_signals_state (void)
  39 {
  40 #ifdef HAVE_SIGACTION
  41   int i;
  42   int res;
  43
  44   res = sigprocmask (0,  NULL, &original_signal_mask);
  45   if (res == -1)
  46     perror_with_name (("sigprocmask"));
  47
  48   for (i = 1; i < NSIG; i++)
  49     {
  50       struct sigaction *oldact = &original_signal_actions[i];
  51
  52       res = sigaction (i, NULL, oldact);
  53       if (res == -1 && errno == EINVAL)
  54         {
  55           /* Some signal numbers in the range are invalid.  */
  56           continue;
  57         }
  58       else if (res == -1)
  59         perror_with_name (("sigaction"));
  60
  61       /* If we find a custom signal handler already installed, then
  62          this function was called too late.  */
  63       if (oldact->sa_handler != SIG_DFL && oldact->sa_handler != SIG_IGN)
  64         internal_error (__FILE__, __LINE__, _("unexpected signal handler"));
  65     }
  66 #endif
  67 }
  68
  69 /* See signals-state-save-restore.h.   */
  70
  71 void
  72 restore_original_signals_state (void)
  73 {
  74 #ifdef HAVE_SIGACTION
  75   int i;
  76   int res;
  77
  78   for (i = 1; i < NSIG; i++)
  79     {
  80       res = sigaction (i, &original_signal_actions[i], NULL);
  81       if (res == -1 && errno == EINVAL)
  82         {
  83           /* Some signal numbers in the range are invalid.  */
  84           continue;
  85         }
  86       else if (res == -1)
  87         perror_with_name (("sigaction"));
  88     }
  89
  90   res = sigprocmask (SIG_SETMASK,  &original_signal_mask, NULL);
  91   if (res == -1)
  92     perror_with_name (("sigprocmask"));
  93 #endif
  94 }