Re: [patch/rfc] Test SA_SIGINFO and nexti/stepi

[Andrew Cagney <cagney at gnu dot org>]

> Hello,
>
> The attached test first checks that GDB can correctly backtrace through a SA_SIGINFO / sa_sigaction signal handler and second checks that GDB can nexti/stepi the program out of such a situtation.
>
> Since, on GNU/Linux i386 stepi is ok but nexti appears to skip the signal trampoline frame, I'll need to find/fix some bugs before committing this.
>
> Anyway, comments.

Here's what I committed, only difference is that step, and not stepi was 
used when unwinding the stack.  I'll test "stepi" separatly.

Andrew

2004-04-15  Andrew Cagney  <cagney@redhat.com>

	* gdb.base/siginfo.c: New file.
	* gdb.base/siginfo.exp: New file.

Index: gdb.base/siginfo.c
===================================================================
RCS file: gdb.base/siginfo.c
diff -N gdb.base/siginfo.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gdb.base/siginfo.c	15 Apr 2004 21:12:51 -0000
@@ -0,0 +1,68 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2004 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 2 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, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+*/
+
+#include <stdio.h>
+#include <signal.h>
+#include <sys/time.h>
+
+static volatile int done;
+
+#ifdef SA_SIGINFO
+static void /* HANDLER */
+handler (int sig, siginfo_t *info, void *context)
+{
+  done = 1;
+} /* handler */
+#else
+static void
+handler (int sig)
+{
+  done = 1;
+} /* handler */
+#endif
+
+main ()
+{
+  /* Set up the signal handler.  */
+  {
+    struct sigaction action;
+    memset (&action, 0, sizeof (action));
+#ifdef SA_SIGINFO
+    action.sa_sigaction = handler;
+    action.sa_flags |= SA_SIGINFO;
+#else
+    action.sa_handler = handler;
+#endif
+    sigaction (SIGVTALRM, &action, NULL);
+  }
+
+  /* Set up a one-off timer.  A timer, rather than SIGSEGV, is used as
+     after a timer handler finishes the interrupted code can safely
+     resume.  */
+  {
+    struct itimerval itime;
+    memset (&itime, 0, sizeof (itime));
+    itime.it_value.tv_usec = 250 * 1000;
+    setitimer (ITIMER_VIRTUAL, &itime, NULL);
+  }
+  /* Wait.  */
+  while (!done);
+  return 0;
+} /* main */
Index: gdb.base/siginfo.exp
===================================================================
RCS file: gdb.base/siginfo.exp
diff -N gdb.base/siginfo.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gdb.base/siginfo.exp	15 Apr 2004 21:12:51 -0000
@@ -0,0 +1,91 @@
+# Copyright 2004 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 2 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, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
+
+
+# The program siginfo.c creates a backtrace containing a signal
+# handler registered using sigaction's sa_sigaction / SA_SIGINFO.
+# Some OS's (e.g., GNU/Linux) use different signal trampolines for
+# sa_sigaction and sa_handler.
+
+# This test first confirms that GDB can backtrace through the
+# alternative sa_sigaction signal handler, and second that GDB can
+# nexti/stepi out of such a handler.
+
+if [target_info exists gdb,nosignals] {
+    verbose "Skipping signals.exp because of nosignals."
+    continue
+}
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 0
+set bug_id 0
+
+set testfile siginfo
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile ${module}.c"
+    return -1
+}
+
+# get things started
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+gdb_test "display/i \$pc"
+
+# Advance to main
+if { ![runto_main] } then {
+    gdb_suppress_tests;
+}
+
+# Pass all the alarms straight through (but verbosely)
+# gdb_test "handle SIGALRM print pass nostop"
+# gdb_test "handle SIGVTALRM print pass nostop"
+# gdb_test "handle SIGPROF print pass nostop"
+
+# Run to the signal handler, validate the backtrace.
+gdb_test "break handler"
+gdb_test "continue" ".* handler .*" "continue to stepi handler"
+send_gdb "bt\n"
+gdb_expect_list "backtrace for nexti" ".*$gdb_prompt $" {
+    "\[\r\n\]+.0 \[^\r\n\]* handler "
+    "\[\r\n\]+.1  .signal handler called."
+    "\[\r\n\]+.2 \[^\r\n\]* main .*"
+}
+
+# Check that GDB can step the inferior back to main
+set test "step out of handler"
+gdb_test_multiple "step" "${test}" {
+    -re "done = 1;.*${gdb_prompt} $" {
+	send_gdb "$i\n"
+	exp_continue
+    }
+    -re "\} .. handler .*${gdb_prompt} $" {
+	send_gdb "step\n"
+	exp_continue
+    }
+    -re "return 0.*${gdb_prompt} $" {
+	# Stepping out of a function GDB advances the inferior to the
+	# start of the next line
+	pass "$test"
+    }
+}