gdbsupport/signals-state-save-restore.cc

   1 /* Copyright (C) 2016-2024 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 "signals-state-save-restore.h"
  19 #include "gdbsupport/gdb-sigmask.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 static sigset_t original_signal_mask;
  29 #endif
  30
  31 /* See signals-state-save-restore.h.   */
  32
  33 void
  34 save_original_signals_state (bool quiet)
  35 {
  36 #ifdef HAVE_SIGACTION
  37   int i;
  38   int res;
  39
  40   res = gdb_sigmask (0,  NULL, &original_signal_mask);
  41   if (res == -1)
  42     perror_with_name (("sigprocmask"));
  43
  44   bool found_preinstalled = false;
  45
  46   for (i = 1; i < NSIG; i++)
  47     {
  48       struct sigaction *oldact = &original_signal_actions[i];
  49
  50       res = sigaction (i, NULL, oldact);
  51       if (res == -1 && errno == EINVAL)
  52         {
  53           /* Some signal numbers in the range are invalid.  */
  54           continue;
  55         }
  56       else if (res == -1)
  57         perror_with_name (("sigaction"));
  58
  59       /* If we find a custom signal handler already installed, then
  60          this function was called too late.  This is a warning instead
  61          of an internal error because this can also happen if you
  62          LD_PRELOAD a library that installs a signal handler early via
  63          __attribute__((constructor)), like libSegFault.so.  */
  64       if (!quiet
  65           && oldact->sa_handler != SIG_DFL
  66           && oldact->sa_handler != SIG_IGN)
  67         {
  68           found_preinstalled = true;
  69
  70           /* Use raw fprintf here because we're being called in early
  71              startup, before GDB's filtered streams are created.  */
  72           fprintf (stderr,
  73                    _("warning: Found custom handler for signal "
  74                      "%d (%s) preinstalled.\n"), i,
  75                    strsignal (i));
  76         }
  77     }
  78
  79   if (found_preinstalled)
  80     {
  81       fprintf (stderr, _("\
  82 Some signal dispositions inherited from the environment (SIG_DFL/SIG_IGN)\n\
  83 won't be propagated to spawned programs.\n"));
  84     }
  85 #endif
  86 }
  87
  88 /* See signals-state-save-restore.h.   */
  89
  90 void
  91 restore_original_signals_state (void)
  92 {
  93 #ifdef HAVE_SIGACTION
  94   int i;
  95   int res;
  96
  97   for (i = 1; i < NSIG; i++)
  98     {
  99       res = sigaction (i, &original_signal_actions[i], NULL);
 100       if (res == -1 && errno == EINVAL)
 101         {
 102           /* Some signal numbers in the range are invalid.  */
 103           continue;
 104         }
 105       else if (res == -1)
 106         perror_with_name (("sigaction"));
 107     }
 108
 109   res = gdb_sigmask (SIG_SETMASK,  &original_signal_mask, NULL);
 110   if (res == -1)
 111     perror_with_name (("sigprocmask"));
 112 #endif
 113 }