[PR,gdb/8527] Interrupt not functional in Eclipse/CDT on Solaris
Commit Message
Hi Joel,
>>> In Solaris:
>>>
>>> If gdb attaches to a process that either has no controlling terminal,
>>> or the controlling terminal differs from the one gdb is running under,
>>> break/^C doesn't interrupt the debugged process.
>>>
>>> This is a fix that was proposed for this problem quite awhile ago but
>>> never implemented; it's been in the Adacore GDB branch for quite
>>> awhile.
>>>
>>> Without going into unnecessary details I cannot easily run the test
>>> suite against this change right now. If this patch gets rejected
>>> based on that, when I have time I'll see about getting IllumOS
>>> installed in a VM and test it there, but the problem was originally
>>> found in sparc Solaris.
>>>
>>> ----
>>>
>>> note: this patch was tested against 8.1.1. It looks like it probably
>>> still applies on the 8.2 branch, but I won't be able to test it until
>>> 8.2 is released.
>>>
>>> -brian
>>>
>>> ps, my assignment/release forms were completed/received 10/30/2017
>>
>>> gdb/Changelog:
>>> 2018-08-07 Brian Vandenberg <phantall@gmail.com>
>>>
>>> PR gdb/8527
>>> * procfs.c (proc_wait_for_stop): calls to set_sigint_trap and
>>> clear_sigint_trap.
>>
>> I'm not sure anyone took the time to answer this message; if not,
>> I apologize.
>
> I'm sorry it took me so long, too, first to get well again and then to
> get to this.
>
>> I can testify that, for as long as we got the patch in the AdaCore
>> sources, we never noticed any ill effect. We never got to validate
>> it against the official testsuite, unfortunately, because for some
>> reason, when I did so, our Solaris machines would badly crash. Did
>
> This is weird: the only time I saw something like this was with a few
> Solaris 12/11.4 Beta builds.
>
>> you run the testsuite before and after the patch, by any chance?
>>
>> Rainer (in Cc:) is our maintainer for Solaris, so he may have an opinion.
>
> I've now regtested the patch on both amd64-pc-solaris2.11 and
> sparcv9-sun-solaris2.11. Initially, gdb.base/attach.exp seemed to
> regress on 32-bit Solaris/SPARC, but that turned out to be due to
> flakyness of parts of the testsuite on Solaris.
>
>> In the meantime, I have a trivial coding style comment:
>>
>>>
>>> diff --git a/gdb/procfs.c b/gdb/procfs.c
>>> index 7b7ff45..7cd870c 100644
>>> --- a/gdb/procfs.c
>>> +++ b/gdb/procfs.c
>>> @@ -913,7 +913,12 @@ proc_wait_for_stop (procinfo *pi)
>>>
>>> procfs_ctl_t cmd = PCWSTOP;
>>>
>>> + /* PR gdb/8527
>>> + * Was not correctly interrupting the inferior process
>>> + * when ^C was pressed in the debug terminal.
>>> + */
>>
>> For multiline comments like the above, we do not repeat the '*'
>> at the beginning of each line.
>>
>> /* PR gdb/8527: Was not correctly interrupting the inferior process
>> when ^C was pressed in the debug terminal. */
>>
>> And if I may, reading this sentence, it's a bit hard to understand
>> what the comment is trying to explain. The following might be
>> a little more precise:
>>
>> /* PR gdb/8527: Call set_sigint_trap to make sure that a ctrl-c
>> pressed in the debugger terminal gets passed down to the
>> inferior, thus causing it to be interrupted. */
>
> TBH, I'd just leave off the comments: this is just what
> set_sigint_trap/clear_sigint_trap are supposed to do. No other use
> comments on this, and the PR reference can easily be found in the commit
> message and the ChangeLog.
>
>>> + set_sigint_trap();
>
> Another nit: blank before (), here and below.
>
>>> win = (write (pi->ctl_fd, (char *) &cmd, sizeof (cmd)) == sizeof (cmd));
>>> +
>>> + /* PR gdb/8527 */
>>> + clear_sigint_trap();
>>> +
>>> /* We been runnin' and we stopped -- need to update status. */
>>> pi->status_valid = 0;
>
> When I noticed that we don't have any test for this issue, I started to
> develop one. This turned out to be a rough trip and my first foray into
> the gdb testsuite, so please bear with me.
>
> Looking for possible testcases to modify, I first came
> gdb.base/interrupt-daemon.exp. However, there turned out to be two
> issues: I'd needed the pid of the grandchild process to attach to, and
> this wasn't emitted to gdb.log when printed.
>
> Besides, when I checked the test as is, it already FAILs on Solaris.
> This seems to happen because set follow-fork-mode child isn't
> implemented, but fails silently and the list of targets supporting it is
> is either incomplete or completely missing in the tests that use it.
>
> Next, I started with a copy of gdb.base/random-signal.c, adding a call
> to setpgrp to detach it from its controling terminal.
>
> Initially, that test FAILed, too, because it expected a
>
> Program received signal SIGINT.*
>
> message while on Solaris I get
>
> Thread N received signal SIGINT.*
>
> I suppose that's because starting with Solaris 10, every process is
> multithreaded. Once I allowed for that form, too, the test PASSed on
> Solaris, both for the run and attach cases. I'll go through the
> testsuite and allow for both cases there, too, probably causing several
> tests to magically PASS now ;-)
>
> As expected, with unmodified gdb, I get the expected
>
> FAIL: gdb.base/signal-no-ctty.exp: attach: stop with control-c (timeout)
>
> However, when I tested the testcase on Linux/x86_64, it FAILs:
>
> attach 113292
> Attaching to program:
> /vol/gcc/obj/gdb/gdb/dist/gdb/testsuite/outputs/gdb.base/signal-no-ctty/signal-no-ctty,
> process 113292
> warning: process 113292 is a zombie - the process has already terminated
> ptrace: Operation not permitted.
> (gdb) FAIL: gdb.base/signal-no-ctty.exp: attach: attach
>
> The weird thing is that both with the setpgrp call and when run like
>
> $ ./signal-no-ctty < /dev/null >& /dev/null &
>
> ps still shows a controlling terminal for the process. Don't yet know
> what's going on here.
>
> Current patch attached for reference.
I never got a reply to this one, but I think I just figured out the
testcase part myself. Tested on amd64-pc-solaris2.11 and
sparcv9-sun-solaris2.11 (test fails before with
FAIL: gdb.base/signal-no-ctty.exp: child: stop with control-c (timeout)
and passes after) and x86_64-pc-linux-gnu.
Ok for master?
Rainer
Comments
Hi Rainer,
On 02/26/2019 03:14 PM, Rainer Orth wrote:
>> Looking for possible testcases to modify, I first came
>> gdb.base/interrupt-daemon.exp. However, there turned out to be two
>> issues: I'd needed the pid of the grandchild process to attach to, and
>> this wasn't emitted to gdb.log when printed.
>>
>> Besides, when I checked the test as is, it already FAILs on Solaris.
>> This seems to happen because set follow-fork-mode child isn't
>> implemented, but fails silently and the list of targets supporting it is
>> is either incomplete or completely missing in the tests that use it.
It's a shame that the Solaris port doesn't support follow-fork. I don't
suppose there's anything fundamentally impossible. I'm sure it must
be possible to intercept fork/vfork/exec events with procfs.
>> However, when I tested the testcase on Linux/x86_64, it FAILs:
>>
>> attach 113292
>> Attaching to program:
>> /vol/gcc/obj/gdb/gdb/dist/gdb/testsuite/outputs/gdb.base/signal-no-ctty/signal-no-ctty,
>> process 113292
>> warning: process 113292 is a zombie - the process has already terminated
>> ptrace: Operation not permitted.
>> (gdb) FAIL: gdb.base/signal-no-ctty.exp: attach: attach
>>
>> The weird thing is that both with the setpgrp call and when run like
>>
>> $ ./signal-no-ctty < /dev/null >& /dev/null &
>>
>> ps still shows a controlling terminal for the process. Don't yet know
>> what's going on here.
>>
>> Current patch attached for reference.
> I never got a reply to this one, but I think I just figured out the
> testcase part myself.
I'm curious -- what was the issue on Linux?
> +++ b/gdb/testsuite/gdb.base/sigint-no-ctty.exp
> @@ -0,0 +1,87 @@
> +# Copyright 2019 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/>. */
> +
Please add a small intro comment mentioning what the testcase is about.
AFAICT, this is basically testing the same thing that
gdb.base/interrupt-daemon.exp is testing, with the difference that it
exercises inferiors started with "attach" instead of "run". I'd suggest
renaming the testcase to interrupt-daemon-attach.exp, so that it sits
alongside interrupt-daemon.exp.
> +if [target_info exists gdb,nosignals] {
> + verbose "Skipping signal-no-ctty.exp because of nosignals."
> + continue
> +}
> +
> +# This test requires sending ^C to interrupt the running target.
> +if [target_info exists gdb,nointerrupts] {
> + verbose "Skipping signal-no-ctty.exp because of nointerrupts."
> + return
> +}
> +
> +standard_testfile
> +
> +if { [build_executable ${testfile}.exp ${testfile} $srcfile {debug}] == -1 } {
> + return -1
> +}
> +
> +proc do_test {} {
> + global binfile
> + global decimal
> +
> + set test_spawn_id [spawn_wait_for_attach $binfile]
This is missing a can_wait_for_attach check:
$ make check TESTS="gdb.base/sigint-no-ctty.exp" RUNTESTFLAGS="--target_board=native-gdbserver"
...
ERROR: tcl error sourcing src/gdb/testsuite/gdb.base/sigint-no-ctty.exp.
ERROR: can't spawn for attach with this target/board
while executing
"error "can't spawn for attach with this target/board""
invoked from within
"if ![can_spawn_for_attach] {
# The caller should have checked can_spawn_for_attach itself
# before getting here.
error "can't spawn for attach with..."
(procedure "spawn_wait_for_attach" line 4)
invoked from within
Otherwise, this is fine with me.
Thanks,
Pedro Alves
# HG changeset patch
# Parent 14950de898700dec7316fb3a5691413d651ddf42
Can't interrupt process without controlling terminal on Solaris (PR gdb/8527)
2018-08-07 Brian Vandenberg <phantall@gmail.com>
gdb:
PR gdb/8527
* procfs.c (proc_wait_for_stop): Wrap write of PCWSTOP in
set_sigint_trap, clear_sigint_trap.
gdb/testsuite:
PR gdb/8527
* gdb.base/sigint-no-ctty.c, gdb.base/sigint-no-ctty.exp: New
test.
@@ -909,7 +909,12 @@ proc_wait_for_stop (procinfo *pi)
procfs_ctl_t cmd = PCWSTOP;
+ set_sigint_trap ();
+
win = (write (pi->ctl_fd, (char *) &cmd, sizeof (cmd)) == sizeof (cmd));
+
+ clear_sigint_trap ();
+
/* We been runnin' and we stopped -- need to update status. */
pi->status_valid = 0;
new file mode 100644
@@ -0,0 +1,61 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2017-2019 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 <unistd.h>
+
+/* GDB reads this to figure out the child's PID. */
+pid_t child_pid;
+
+void
+marker (void)
+{
+}
+
+int
+main ()
+{
+ /* Don't let the test case run forever. */
+ alarm (60);
+
+ child_pid = fork ();
+
+ switch (child_pid)
+ {
+ case -1:
+ return 1;
+
+ case 0:
+ break;
+
+ default:
+ while (1)
+ {
+ marker ();
+ usleep (1000);
+ }
+ }
+
+ /* Detach from controlling terminal. */
+ if (setsid () == (pid_t) -1)
+ return 1;
+
+ for (;;)
+ ;
+
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,87 @@
+# Copyright 2019 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/>. */
+
+if [target_info exists gdb,nosignals] {
+ verbose "Skipping signal-no-ctty.exp because of nosignals."
+ continue
+}
+
+# This test requires sending ^C to interrupt the running target.
+if [target_info exists gdb,nointerrupts] {
+ verbose "Skipping signal-no-ctty.exp because of nointerrupts."
+ return
+}
+
+standard_testfile
+
+if { [build_executable ${testfile}.exp ${testfile} $srcfile {debug}] == -1 } {
+ return -1
+}
+
+proc do_test {} {
+ global binfile
+ global decimal
+
+ set test_spawn_id [spawn_wait_for_attach $binfile]
+ set parent_pid [spawn_id_get_pid $test_spawn_id]
+
+ # Attach to the parent, run it to a known point, extract the
+ # child's PID, and detach.
+ with_test_prefix "parent" {
+ clean_restart ${binfile}
+
+ gdb_test "attach $parent_pid" \
+ "Attaching to program.*, process $parent_pid.*" \
+ "attach"
+
+ gdb_breakpoint "marker"
+ gdb_continue_to_breakpoint "marker"
+
+ set child_pid [get_integer_valueof "child_pid" -1]
+ if {$child_pid == -1} {
+ return
+ }
+
+ gdb_test "detach" \
+ "Detaching from program: .*process $parent_pid\r\n\\\[Inferior $decimal \\(.*\\) detached\\\]"
+
+ remote_exec host "kill -9 $parent_pid"
+ }
+
+ # Start over, and attach to the child this time.
+ with_test_prefix "child" {
+ global gdb_prompt
+
+ clean_restart $binfile
+
+ gdb_test "attach $child_pid" \
+ "Attaching to program.*, process $child_pid.*" \
+ "attach"
+
+ gdb_test_multiple "continue" "continue" {
+ -re "Continuing" {
+ pass "continue"
+ }
+ }
+
+ after 500 {send_gdb "\003"}
+ gdb_test "" "(Program|Thread .*) received signal SIGINT.*" \
+ "stop with control-c"
+
+ remote_exec host "kill -9 $child_pid"
+ }
+}
+
+do_test