Test interrupting programs that block SIGINT [gdb/9425, gdb/14559]

This adds a couple testcases that exercise interrupting programs that
block SIGINT.  One tests a program that uses sigprocmask to mask out
SIGINT, and the other tests a program that waits for SIGINT with
sigwait.  On GNU/Linux, it is currently impossible to interrupt such a
program with Ctrl-C, and you can't interrupt it with the "interrupt"
command in all-stop mode either.

These currently fail, and are suitably kfailed.  The rest of the
series will fix the fails.

Tested on GNU/Linux native, gdbserver, and gdbserver + "maint set
target-non-stop on".

gdb/testsuite/ChangeLog:
yyyy-mm-dd  Pedro Alves  <pedro@palves.net>

	PR gdb/9425
	PR gdb/14559
	* gdb.base/sigint-masked-out.c: New file.
	* gdb.base/sigint-masked-out.exp: New file.
	* gdb.base/sigint-sigwait.c: New file.
	* gdb.base/sigint-sigwait.exp: New file.

Change-Id: Iddb70c0a2c92550027fccb6f51ecba1292d233c8

gdb/testsuite/gdb.base/sigint-masked-out.c

@@ -0,0 +1,43 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 Free Software Foundation, Inc.
+
+   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 <unistd.h>
+#include <signal.h>
+
+static void
+done ()
+{
+}
+
+int
+main (int argc, char *argv[])
+{
+  int i;
+  sigset_t sigs;
+
+  alarm (30);
+
+  sigfillset (&sigs);
+  sigprocmask (SIG_SETMASK, &sigs, NULL);
+
+  done ();
+
+  while (1)
+    sleep (1);
+
+  return 0;
+}

gdb/testsuite/gdb.base/sigint-masked-out.exp

@@ -0,0 +1,101 @@
+# Copyright 2021 Free Software Foundation, Inc.
+#
+# 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/>.
+
+# Make sure that we can interrupt an inferior that has all signals
+# masked out, including SIGINT, with both Ctrl-C and the "interrupt"
+# command.
+
+standard_testfile
+
+if {[build_executable "failed to build" $testfile $srcfile {debug}]} {
+    return -1
+}
+
+# Test interrupting with Ctrl-C.
+
+proc_with_prefix test_ctrl_c {} {
+    global binfile
+    global gdb_prompt
+
+    clean_restart $binfile
+
+    if ![runto "done"] {
+	fail "can't run to done function"
+	return
+    }
+
+    gdb_test_multiple "continue" "" {
+	-re "Continuing" {
+	    pass $gdb_test_name
+	}
+    }
+
+    after 200
+
+    send_gdb "\003"
+
+    gdb_test_multiple "" "ctrl-c stops process" {
+	-timeout 5
+	-re -wrap "(received signal SIGINT|stopped).*" {
+	    pass $gdb_test_name
+	}
+	timeout {
+	    setup_kfail "gdb/9425" *-*-*
+	    fail "$gdb_test_name (timeout)"
+	}
+    }
+}
+
+# Test interrupting with the "interrupt" command.
+
+proc_with_prefix test_interrupt_cmd {} {
+    global binfile
+    global gdb_prompt
+
+    clean_restart $binfile
+
+    if ![runto "done"] {
+	fail "can't run to done function"
+	return
+    }
+
+    gdb_test_multiple "continue&" "" {
+	-re "Continuing\\.\r\n$gdb_prompt " {
+	    pass $gdb_test_name
+	}
+    }
+
+    after 200
+
+    gdb_test_multiple "interrupt" "" {
+	-re "$gdb_prompt " {
+	    pass $gdb_test_name
+	}
+    }
+
+    gdb_test_multiple "" "interrupt cmd stops process" {
+	-timeout 5
+	-re "(received signal SIGINT|stopped)" {
+	    pass $gdb_test_name
+	}
+	timeout {
+	    setup_kfail "gdb/14559" *-*-*
+	    fail "$gdb_test_name (timeout)"
+	}
+    }
+}
+
+test_ctrl_c
+test_interrupt_cmd

gdb/testsuite/gdb.base/sigint-sigwait.c

@@ -0,0 +1,80 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2021 Free Software Foundation, Inc.
+
+   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 <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+static void
+handle_sigint (int signo)
+{
+}
+
+static void
+done ()
+{
+}
+
+int
+main (int argc, char **argv)
+{
+  sigset_t signal_set;
+  struct sigaction s;
+
+  alarm (30);
+
+  s.sa_flags = SA_RESTART;
+  s.sa_handler = handle_sigint;
+
+  if (sigaction (SIGINT, &s, NULL) < 0)
+    {
+      perror ("<%s> Error sigaction: ");
+      exit (2);
+    }
+
+  if (sigfillset (&signal_set) < 0)
+    {
+      perror ("<main> Error sigfillset(): ");
+      exit (2);
+    }
+
+  done ();
+
+  while (1)
+    {
+      int sig;
+
+      /* Wait for queued signals.  .*/
+      if (sigwait (&signal_set, &sig) != 0)
+	{
+	  perror ("<main> Error sigwait(): ");
+	  exit (1);
+	}
+
+      /* Process signal.  */
+      if (sig == SIGINT)
+	{
+	  printf ("Terminating.\n");
+	  exit (0);
+	}
+
+      printf ("Unhandled signal [%s]\n", strsignal (sig));
+    }
+}

gdb/testsuite/gdb.base/sigint-sigwait.exp

@@ -0,0 +1,105 @@
+# Copyright 2021 Free Software Foundation, Inc.
+#
+# 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/>.
+
+# Make sure that we can interrupt an inferior that has all signals
+# masked out, including SIGINT, and then waits for signals with
+# sigwait.  Test interrupting with both Ctrl-C and the "interrupt"
+# command.
+
+standard_testfile
+
+if {[build_executable "failed to build" $testfile $srcfile {debug}]} {
+    return -1
+}
+
+# Test interrupting with Ctrl-C.
+
+proc_with_prefix test_ctrl_c {} {
+    global binfile
+    global gdb_prompt
+
+    clean_restart $binfile
+
+    if ![runto "done"] {
+	fail "can't run to done function"
+	return
+    }
+
+    gdb_test_multiple "continue" "" {
+	-re "Continuing" {
+	    pass $gdb_test_name
+	}
+    }
+
+    after 200
+
+    send_gdb "\003"
+
+    global exited_normally_re
+
+    gdb_test_multiple "" "ctrl-c stops process" {
+	-re -wrap "(received signal SIGINT|stopped).*" {
+	    pass $gdb_test_name
+	}
+	-re -wrap "Inferior.*exited normally.*" {
+	    setup_kfail "gdb/9425" *-*-*
+	    fail "$gdb_test_name (the program exited)"
+	}
+    }
+}
+
+# Test interrupting with the "interrupt" command.
+
+proc_with_prefix test_interrupt_cmd {} {
+    global binfile
+    global gdb_prompt
+
+    clean_restart $binfile
+
+    if ![runto "done"] {
+	fail "can't run to done function"
+	return
+    }
+
+    gdb_test_multiple "continue&" "" {
+	-re "Continuing\\.\r\n$gdb_prompt " {
+	    pass $gdb_test_name
+	}
+    }
+
+    after 200
+
+    gdb_test_multiple "interrupt" "" {
+	-re "$gdb_prompt " {
+	    pass $gdb_test_name
+	}
+    }
+
+    global exited_normally_re
+
+    gdb_test_multiple "" "interrupt cmd stops process" {
+	-timeout 5
+	-re "(received signal SIGINT|stopped)" {
+	    pass $gdb_test_name
+	}
+	-re "Inferior.*exited normally" {
+	    setup_kfail "gdb/14559" *-*-*
+	    fail "$gdb_test_name (the program exited)"
+	}
+    }
+}
+
+test_ctrl_c
+test_interrupt_cmd