1 files changed, 114 insertions, 0 deletions
diff --git a/gdbsupport/signals-state-save-restore.c b/gdbsupport/signals-state-save-restore.c
new file mode 100644
index 00000000000..c292d498daf
--- /dev/null
+++ b/gdbsupport/signals-state-save-restore.c
@@ -0,0 +1,114 @@
+/* Copyright (C) 2016-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "signals-state-save-restore.h"
+#include "gdbsupport/gdb-sigmask.h"
+
+#include <signal.h>
+
+/* The original signal actions and mask.  */
+
+#ifdef HAVE_SIGACTION
+static struct sigaction original_signal_actions[NSIG];
+
+static sigset_t original_signal_mask;
+#endif
+
+/* See signals-state-save-restore.h.   */
+
+void
+save_original_signals_state (bool quiet)
+{
+#ifdef HAVE_SIGACTION
+  int i;
+  int res;
+
+  res = gdb_sigmask (0,  NULL, &original_signal_mask);
+  if (res == -1)
+    perror_with_name (("sigprocmask"));
+
+  bool found_preinstalled = false;
+
+  for (i = 1; i < NSIG; i++)
+    {
+      struct sigaction *oldact = &original_signal_actions[i];
+
+      res = sigaction (i, NULL, oldact);
+      if (res == -1 && errno == EINVAL)
+	{
+	  /* Some signal numbers in the range are invalid.  */
+	  continue;
+	}
+      else if (res == -1)
+	perror_with_name (("sigaction"));
+
+      /* If we find a custom signal handler already installed, then
+	 this function was called too late.  This is a warning instead
+	 of an internal error because this can also happen if you
+	 LD_PRELOAD a library that installs a signal handler early via
+	 __attribute__((constructor)), like libSegFault.so.  */
+      if (!quiet
+	  && oldact->sa_handler != SIG_DFL
+	  && oldact->sa_handler != SIG_IGN)
+	{
+	  found_preinstalled = true;
+
+	  /* Use raw fprintf here because we're being called in early
+	     startup, before GDB's filtered streams are created.  */
+	  fprintf (stderr,
+		   _("warning: Found custom handler for signal "
+		     "%d (%s) preinstalled.\n"), i,
+		   strsignal (i));
+	}
+    }
+
+  if (found_preinstalled)
+    {
+      fprintf (stderr, _("\
+Some signal dispositions inherited from the environment (SIG_DFL/SIG_IGN)\n\
+won't be propagated to spawned programs.\n"));
+    }
+#endif
+}
+
+/* See signals-state-save-restore.h.   */
+
+void
+restore_original_signals_state (void)
+{
+#ifdef HAVE_SIGACTION
+  int i;
+  int res;
+
+  for (i = 1; i < NSIG; i++)
+    {
+      res = sigaction (i, &original_signal_actions[i], NULL);
+      if (res == -1 && errno == EINVAL)
+	{
+	  /* Some signal numbers in the range are invalid.  */
+	  continue;
+	}
+      else if (res == -1)
+	perror_with_name (("sigaction"));
+    }
+
+  res = gdb_sigmask (SIG_SETMASK,  &original_signal_mask, NULL);
+  if (res == -1)
+    perror_with_name (("sigprocmask"));
+#endif
+}