[PATCH v3] Enable 'set print inferior-events' and improve detach/fork/kill/exit messages
Pedro Alves
palves@redhat.com
Mon Mar 26 10:58:00 GMT 2018
On 03/09/2018 09:55 PM, Sergio Durigan Junior wrote:
> But if we use 'add_thread_silent' (with the same configuration as
> before):
>
> (gdb) run
> Starting program: a.out
> [Attaching after process 26807 fork to child process 26807.]
> [New inferior 26811]
> [Detaching after fork from child process 26811.]
> [Inferior 26807 detached]
> [Inferior 2 (process 26811) exited normally]
I still think the "inferior PID" messages are misleading,
because PID is not the inferior number. I think it would be
better if they read something like:
[Attaching after process 26807 fork to child process 26807.]
- [New inferior 26811]
+ [New inferior 2 (process 26811)]
[Detaching after fork from child process 26811.]
- [Inferior 26807 detached]
+ [Inferior 1 (process 26807) detached]
[Inferior 2 (process 26811) exited normally]
I.e.:
[Attaching after process 26807 fork to child process 26807.]
[New inferior 2 (process 26811)]
[Detaching after fork from child process 26811.]
[Inferior 1 (process 26807) detached]
[Inferior 2 (process 26811) exited normally]
Please consider fixing that at the same time.
> @@ -2598,8 +2598,14 @@ kill_command (const char *arg, int from_tty)
> error (_("The program is not being run."));
> if (!query (_("Kill the program being debugged? ")))
> error (_("Not confirmed."));
> + pid_t pid = ptid_get_pid (inferior_ptid);
> + int infnum = current_inferior ()->num;
> target_kill ();
>
> + if (print_inferior_events)
> + printf_unfiltered (_("[Inferior %d (process %d) has been killed]\n"),
> + infnum, pid);
The "process %d" part should be using target_pid_to_str instead.
Not all targets have the concept of a "process" (e.g., when remote
debugging a bare metal system), or have access to the actual pid
number (older gdbservers). In such case, the above prints
the fake internal magic process id (magic_null_ptid). E.g.:
$ ./gdb -q --batch -ex "set remote multiprocess-feature-packet off" -ex "tar rem :9999" -ex "info inferiors" -ex "kill"
Num Description Executable
* 1 Remote target gdb/binutils-gdb/build/gdb/gdbserver/gdbserver
^^^^^^^^^^^^^
Kill the program being debugged? (y or n)
[Inferior 1 (process 42000) has been killed]
^^^^^^^^^^^^^
You'll need to capture the target_pid_to_str output
before killing, otherwise after target_kill the target
might no longer be pushed on the target stack.
This pattern appears in several places in the patch.
The fork-related paths should be fine to print inf->pid directly,
since fork implies support for multiple processes.
> diff --git a/gdb/testsuite/gdb.base/catch-syscall.exp b/gdb/testsuite/gdb.base/catch-syscall.exp
> index 2a8bf27e5c..20fa041155 100644
> --- a/gdb/testsuite/gdb.base/catch-syscall.exp
> +++ b/gdb/testsuite/gdb.base/catch-syscall.exp
> @@ -179,7 +179,7 @@ proc check_for_program_end {} {
> # Deleting the catchpoints
> delete_breakpoints
>
> - gdb_continue_to_end
> + gdb_continue_to_end "" continue 1
Changes like this appear several times in the patch -- can you
expand on why they're needed?
> +
> +if { [use_gdb_stub] } {
> + untested "not supported on gdbserver"
There should be a comment above this mentioning what
wouldn't work with gdbserver, since it's not obvious to
me. (I think we may have gone through that in a previous
iteration, but it'd be better if the reason was written
down here).
Note: it's not "on gdbserver", it's on "target remote" stubs.
gdbserver+extended-remote works. And there are stubs others
than gdbserver.
> diff --git a/gdb/testsuite/gdb.threads/process-dies-while-detaching.c b/gdb/testsuite/gdb.threads/process-dies-while-detaching.c
> index b0fd84b483..1871f6cf81 100644
> --- a/gdb/testsuite/gdb.threads/process-dies-while-detaching.c
> +++ b/gdb/testsuite/gdb.threads/process-dies-while-detaching.c
> @@ -80,6 +80,8 @@ parent_function (pid_t child)
> alarm (300);
>
> ret = waitpid (child, &status, 0);
> + /* Give a chance to GDB print its messages. */
> + usleep (100);
>
This is probably racy and I'd a prefer a better fix that
avoids it. Why did you need it? What/how does the failure
look like without this? Why does it happen?
> if (ret == -1)
> {
Thanks,
Pedro Alves
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