[PATCH v4] Implement $_exitsignal
Sergio Durigan Junior
sergiodj@redhat.com
Mon Sep 23 21:32:00 GMT 2013
On Tuesday, September 17 2013, I wrote:
> Hi,
>
> This is the fourth attempt to implement $_exitsignal. You can read the
> last 3 at:
>
> - First attempt:
>
> <http://sourceware.org/ml/gdb-patches/2013-06/msg00352.html>
>
> - Second attempt:
>
> <http://sourceware.org/ml/gdb-patches/2013-06/msg00452.html>
>
> - Third attempt:
>
> <https://sourceware.org/ml/gdb-patches/2013-08/msg00727.html>
Ping.
The documentation part has been already reviewed and approved.
Thanks,
> The patch has suffered some changes since the third attempt. In the
> code, I basically addressed Pedro's requests of clearing both
> $_exit{signal,code} when there is no signal recognized at the corefile,
> and (most important) to drop the process of filling $_exitsignal if the
> target doesn't provide a way of converting between GDB's internal signal
> numbers and the target's.
>
> In the documentation field, I wrote a more extensive section explaining
> how to use $_exit{code,signal} together in a GDB script, by making use
> of the new convenience function $_isvoid. This was Doug's request.
>
> I have also obviously added some testcases, but they are unchanged since
> the last attempt.
>
> OK to apply? Thanks,
>
> --
> Sergio
>
> gdb/
> 2013-09-17 Sergio Durigan Junior <sergiodj@redhat.com>
>
> * NEWS: Mention new convenience variable $_exitsignal.
> * corelow.c (core_open): Set $_exitsignal to the uncaught signal
> which generated the corefile; reset $_exitcode to void.
> * infrun.c (handle_inferior_event): Reset $_exitsignal for
> TARGET_WAITKIND_EXITED; set $_exitsignal and reset $_exitcode for
> TARGET_WAITKIND_SIGNALLED.
>
> gdb/testsuite/
> 2013-09-17 Sergio Durigan Junior <sergiodj@redhat.com>
>
> * gdb.base/corefile.exp: Test whether $_exitsignal is set and
> $_exitcode is void when opening a corefile.
> * gdb.base/exitsignal.exp: New file.
> * gdb.base/segv.c: Likewise.
> * gdb.base/normal.c: Likewise.
>
> gdb/doc/
> 2013-09-17 Sergio Durigan Junior <sergiodj@redhat.com>
>
> * gdb.texinfo (Convenience Variables): Document $_exitsignal.
> Update entry for $_exitcode.
>
> diff --git a/gdb/NEWS b/gdb/NEWS
> index af06a21..4c38358 100644
> --- a/gdb/NEWS
> +++ b/gdb/NEWS
> @@ -87,6 +87,10 @@ show range-stepping
> * The exception-related catchpoints, like "catch throw", now accept a
> regular expression which can be used to filter exceptions by type.
>
> +* The new convenience variable $_exitsignal is automatically set to
> + the terminating signal number when the program being debugged dies
> + due to an uncaught signal.
> +
> * MI changes
>
> ** The -trace-save MI command can optionally save trace buffer in Common
> diff --git a/gdb/corelow.c b/gdb/corelow.c
> index 8371b58..9088afb 100644
> --- a/gdb/corelow.c
> +++ b/gdb/corelow.c
> @@ -446,7 +446,22 @@ core_open (char *filename, int from_tty)
>
> printf_filtered (_("Program terminated with signal %s, %s.\n"),
> gdb_signal_to_name (sig), gdb_signal_to_string (sig));
> +
> + /* Set the value of the internal variable $_exitsignal,
> + which holds the signal uncaught by the inferior. */
> + set_internalvar_integer (lookup_internalvar ("_exitsignal"),
> + siggy);
> }
> + else
> + {
> + /* The inferior did not die because of an uncaught signal,
> + therefore we must clear $_exitsignal. */
> + clear_internalvar (lookup_internalvar ("_exitsignal"));
> + }
> +
> + /* Clear the $_exitcode internal variable, because there is no way
> + the inferior could have exited and generated a corefile. */
> + clear_internalvar (lookup_internalvar ("_exitcode"));
>
> /* Fetch all registers from core file. */
> target_fetch_registers (get_current_regcache (), -1);
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 60d2877..104fe2a 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -9751,8 +9751,64 @@ to match the format in which the data was printed.
>
> @item $_exitcode
> @vindex $_exitcode@r{, convenience variable}
> -The variable @code{$_exitcode} is automatically set to the exit code when
> -the program being debugged terminates.
> +When the program being debugged terminates normally, @value{GDBN}
> +automatically sets this variable to the exit code of the program, and
> +resets @code{$_exitsignal} to @code{void}.
> +
> +@item $_exitsignal
> +@vindex $_exitsignal@r{, convenience variable}
> +When the program being debugged dies due to an uncaught signal,
> +@value{GDBN} automatically sets this variable to that signal's number,
> +and resets @code{$_exitcode} to @code{void}.
> +
> +To distinguish between whether the program being debugged has exited
> +(i.e., @code{$_exitcode} is not @code{void}) or signalled (i.e.,
> +@code{$_exitsignal} is not @code{void}), the convenience function
> +@code{$_isvoid} can be used (see @ref{Convenience Funs,, Convenience
> +Functions}). For example, considering the following source code:
> +
> +@smallexample
> +#include <signal.h>
> +
> +int
> +main (int argc, char *argv[])
> +@{
> + raise (SIGALRM);
> + return 0;
> +@}
> +@end smallexample
> +
> +A valid way of telling whether the program being debugged has exited
> +or signalled would be:
> +
> +@smallexample
> +(@value{GDBP}) define has_exited_or_signalled
> +Type commands for definition of ``has_exited_or_signalled''.
> +End with a line saying just ``end''.
> +>if $_isvoid ($_exitsignal)
> + >echo The program has exited\n
> + >else
> + >echo The program has signalled\n
> + >end
> +>end
> +(@value{GDBP}) run
> +Starting program:
> +
> +Program terminated with signal SIGALRM, Alarm clock.
> +The program no longer exists.
> +(@value{GDBP}) has_exited_or_signalled
> +The program has signalled
> +@end smallexample
> +
> +As can be seen, @value{GDBN} correctly informs that the program being
> +debugged has signalled, since it calls @code{raise} and raises a
> +@code{SIGALRM} signal. If the program being debugged had not called
> +@code{raise}, then @value{GDBN} would report a normal exit:
> +
> +@smallexample
> +(@value{GDBP}) has_exited_or_signalled
> +The program has exited
> +@end smallexample
>
> @item $_exception
> The variable @code{$_exception} is set to the exception object being
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index 57618ae..e356f8d 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -3432,6 +3432,10 @@ handle_inferior_event (struct execution_control_state *ecs)
> set_internalvar_integer (lookup_internalvar ("_exitcode"),
> (LONGEST) ecs->ws.value.integer);
>
> + /* Clear the $_exitsignal internal variable, since if we are
> + here the inferior has not been terminated by a signal. */
> + clear_internalvar (lookup_internalvar ("_exitsignal"));
> +
> /* Also record this in the inferior itself. */
> current_inferior ()->has_exit_code = 1;
> current_inferior ()->exit_code = (LONGEST) ecs->ws.value.integer;
> @@ -3439,7 +3443,41 @@ handle_inferior_event (struct execution_control_state *ecs)
> print_exited_reason (ecs->ws.value.integer);
> }
> else
> - print_signal_exited_reason (ecs->ws.value.sig);
> + {
> + struct regcache *regcache = get_thread_regcache (ecs->ptid);
> + struct gdbarch *gdbarch = get_regcache_arch (regcache);
> +
> + if (gdbarch_gdb_signal_to_target_p (gdbarch))
> + {
> + /* Set the value of the internal variable $_exitsignal,
> + which holds the signal uncaught by the inferior. */
> + set_internalvar_integer (lookup_internalvar ("_exitsignal"),
> + gdbarch_gdb_signal_to_target (gdbarch,
> + ecs->ws.value.sig));
> + }
> + else
> + {
> + static int have_warned_signal_to_target = 0;
> +
> + if (!have_warned_signal_to_target)
> + {
> + have_warned_signal_to_target = 1;
> + warning (_("\
> +Cannot fill $_exitsignal with the correct signal number."));
> + }
> +
> + /* Clearing the $_exitsignal convenience variable, since
> + it is not possible to fill it correctly. */
> + clear_internalvar (lookup_internalvar ("_exitsignal"));
> + }
> +
> + print_signal_exited_reason (ecs->ws.value.sig);
> +
> + /* Clear the $_exitcode internal variable, because if the
> + inferior died with a signal then its return code does not
> + exist. */
> + clear_internalvar (lookup_internalvar ("_exitcode"));
> + }
>
> gdb_flush (gdb_stdout);
> target_mourn_inferior ();
> diff --git a/gdb/testsuite/gdb.base/corefile.exp b/gdb/testsuite/gdb.base/corefile.exp
> index 24a33a3..77ef954 100644
> --- a/gdb/testsuite/gdb.base/corefile.exp
> +++ b/gdb/testsuite/gdb.base/corefile.exp
> @@ -142,6 +142,16 @@ gdb_test "print coremaker_ro" "\\\$$decimal = 201"
>
> gdb_test "print func2::coremaker_local" "\\\$$decimal = \\{0, 1, 2, 3, 4\\}"
>
> +# Test the presence and the correct values of $_exitsignal and
> +# $_exitcode variables. The corefile is generated with a SIGABRT,
> +# which is "6" in the Linux kernel.
> +
> +gdb_test "print \$_exitsignal" " = 6" \
> + "\$_exitsignal prints SIGABRT (6)"
> +
> +gdb_test "print \$_exitcode" " = void" \
> + "\$_exitcode is void"
> +
> # Somehow we better test the ability to read the registers out of the core
> # file correctly. I don't think the other tests do this.
>
> diff --git a/gdb/testsuite/gdb.base/exitsignal.exp b/gdb/testsuite/gdb.base/exitsignal.exp
> new file mode 100644
> index 0000000..5ab2fee
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/exitsignal.exp
> @@ -0,0 +1,97 @@
> +# Copyright 2013 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/>.
> +
> +# This test checks both $_exitcode and $_exitsignal variables. The
> +# purpose of this checking is to ensure that the variables are
> +# mutually exclusive, i.e., that when $_exitsignal is set, $_exitcode
> +# is not, and vice-versa. This mutual exclusion happens because if an
> +# inferior exited (either successfuly or not), it certainly was not
> +# killed by a signal. However, if it was killed by an uncaught
> +# signal, then there is no way for it to have exited.
> +
> +standard_testfile segv.c
> +
> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
> + return -1
> +}
> +
> +# Run to main
> +if { ![runto_main] } {
> + return -1
> +}
> +
> +# Print $_exitsignal. It should be void now, because nothing
> +# happened.
> +gdb_test "print \$_exitsignal" " = void" \
> + "\$_exitsignal is void before running"
> +
> +# Just to guarantee, making sure that $_exitcode is also void.
> +gdb_test "print \$_exitcode" " = void" \
> + "\$_exitcode is void before running"
> +
> +# Trigger SIGSEGV.
> +gdb_test "continue" "Program received signal SIGSEGV.*" "trigger SIGSEGV"
> +
> +# Continue until the end.
> +gdb_test "continue" "Program terminated with signal SIGSEGV.*" \
> + "program terminated with SIGSEGV"
> +
> +# Now, print $_exitsignal again. It should be 11 (SIGSEGV).
> +gdb_test "print \$_exitsignal" " = 11" \
> + "\$_exitsignal is 11 (SIGSEGV) after SIGSEGV."
> +
> +# And $_exitcode should still be void, since the inferior died because
> +# of a signal, and did not return.
> +gdb_test "print \$_exitcode" " = void" \
> + "\$_exitcode is still void after SIGSEGV"
> +
> +# Re-run to main, i.e., restart the executable.
> +rerun_to_main
> +
> +# Print the $_exitsignal again. Even in this normal scenario, it
> +# should still contain the signal triggered in the other run.
> +gdb_test "print \$_exitsignal" " = 11" \
> + "\$_exitsignal is 11 (SIGSEGV) after restarting the inferior"
> +
> +# And, again, print $_exitcode.
> +gdb_test "print \$_exitcode" " = void" \
> + "\$_exitcode is still void after restarting the inferior"
> +
> +# Now we test the behaviour of $_exit{code,signal} during a normal
> +# inferior execution.
> +standard_testfile normal.c
> +
> +if { [prepare_for_testing ${testfile}.exp ${testfile} ${srcfile}] } {
> + return -1
> +}
> +
> +# Checking $_exitsignal and $_exitcode, both should be void before the
> +# inferior is executed.
> +gdb_test "print \$_exitsignal" " = void" \
> + "\$_exitsignal is void before normal inferior is executed"
> +gdb_test "print \$_exitcode" " = void" \
> + "\$_exitcode is void before normal inferior is executed"
> +
> +# Running until the end.
> +gdb_test "run" "\\\[Inferior .* exited normally\\\]" "Run inferior until the end"
> +
> +# Checking $_exitcode. It should be 0.
> +gdb_test "print \$_exitcode" " = 0" \
> + "\$_exitcode is zero after normal inferior is executed"
> +
> +# Checking $_exitsignal. It should still be void, since the inferior
> +# has not received any signal.
> +gdb_test "print \$_exitsignal" " = void" \
> + "\$_exitsignal is still void after normal inferior is executed"
> diff --git a/gdb/testsuite/gdb.base/normal.c b/gdb/testsuite/gdb.base/normal.c
> new file mode 100644
> index 0000000..4aa7c45
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/normal.c
> @@ -0,0 +1,24 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> + Copyright 2013 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/>. */
> +
> +/* This test is just a normal return 0. */
> +
> +int
> +main (int argc, char *argv[])
> +{
> + return 0;
> +}
> diff --git a/gdb/testsuite/gdb.base/segv.c b/gdb/testsuite/gdb.base/segv.c
> new file mode 100644
> index 0000000..8991f4d
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/segv.c
> @@ -0,0 +1,29 @@
> +/* This testcase is part of GDB, the GNU debugger.
> +
> + Copyright 2013 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/>. */
> +
> +/* This test can be used just to generate a SIGSEGV. */
> +
> +#include <signal.h>
> +
> +int
> +main (int argc, char *argv[])
> +{
> + /* Generating a SIGSEGV. */
> + raise (SIGSEGV);
> +
> + return 0;
> +}
--
Sergio
More information about the Gdb-patches
mailing list