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Re: [PATCH v4] Enable 'set print inferior-events' and improve detach/fork/kill/exit messages
- From: Pedro Alves <palves at redhat dot com>
- To: Sergio Durigan Junior <sergiodj at redhat dot com>, GDB Patches <gdb-patches at sourceware dot org>
- Cc: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- Date: Fri, 6 Apr 2018 16:39:19 +0100
- Subject: Re: [PATCH v4] Enable 'set print inferior-events' and improve detach/fork/kill/exit messages
- References: <20180124194714.26222-1-sergiodj@redhat.com> <20180405184648.3055-1-sergiodj@redhat.com>
On 04/05/2018 07:46 PM, Sergio Durigan Junior wrote:
> Changes from v3:
>
> - Revisited commit log and fixed wrong copy&paste from GDB output.
>
> - Use target_pid_to_str where applicable. Use
> gdb::unique_xmalloc_ptr<char> to save results from
> target_pid_to_str in some cases.
Arguably target_pid_to_str implementations should be
using get_print_cell instead of a single static buffer, avoiding
the problem. But that's a larger change, so local copy is fine
with me.
> @@ -2598,8 +2598,16 @@ 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."));
> +
> + const char *pid_str = target_pid_to_str (inferior_ptid);
> + int infnum = current_inferior ()->num;
> +
> target_kill ();
>
> + if (print_inferior_events)
> + printf_unfiltered (_("[Inferior %d (process %s) has been killed]\n"),
> + infnum, pid_str);
This still seem risky -- Target backends use target_pid_to_str inside
target_kill, e.g., when logging is enabled. E.g.,
linux_nat_kill -> -> stop_callback -> target_pid_to_str
ISTM a deep copy like:
std::string pid_str = target_pid_to_str (inferior_ptid);
would be safer/better.
> /* The Current Inferior. This is a strong reference. I.e., whenever
> an inferior is the current inferior, its refcount is
> @@ -123,7 +122,8 @@ add_inferior (int pid)
> struct inferior *inf = add_inferior_silent (pid);
>
> if (print_inferior_events)
> - printf_unfiltered (_("[New inferior %d]\n"), pid);
> + printf_unfiltered (_("[New inferior %d (process %d)]\n"),
> + inf->num, pid);
As discussed in a previous revision, using hardcoded "(process %d)"
doesn't work properly, because PID can be a fake PID number, or the
target may have no concept of processes, e.g., when debugging remote
targets. ISTRM this should use target_pid_to_str as well.
> @@ -266,7 +263,8 @@ detach_inferior (inferior *inf)
> exit_inferior_1 (inf, 0);
>
> if (print_inferior_events)
> - printf_unfiltered (_("[Inferior %d detached]\n"), pid);
> + printf_unfiltered (_("[Inferior %d (process %d) detached]\n"),
> + inf->num, pid);
Ditto.
> - if (info_verbose || debug_infrun)
> + if (print_inferior_events)
> {
> + gdb::unique_xmalloc_ptr<char>
> + parent_pid (xstrdup (target_pid_to_str (parent_ptid)));
> + gdb::unique_xmalloc_ptr<char>
> + child_pid (xstrdup (target_pid_to_str (child_ptid)));
std::string would be simpler than gdb::unique_xmalloc_ptr here:
std::string parent_pid = target_pid_to_str (parent_ptid));
std::string child_pid = target_pid_to_str (child_ptid));
gdb::unique_xmalloc_ptr is handy when you have no way around
malloc/free, but here you're in charge of the dup yourself.
> diff --git a/gdb/remote.c b/gdb/remote.c
> index 68c43f8312..4cb4badd8a 100644
> --- a/gdb/remote.c
> +++ b/gdb/remote.c
> @@ -5137,7 +5137,12 @@ remote_detach_1 (int from_tty, inferior *inf)
> /* If doing detach-on-fork, we don't mourn, because that will delete
> breakpoints that should be available for the followed inferior. */
> if (!is_fork_parent)
> - target_mourn_inferior (inferior_ptid);
> + {
> + target_mourn_inferior (inferior_ptid);
> + if (print_inferior_events)
> + printf_unfiltered (_("[Inferior %d (process %d) detached]\n"),
> + inf->num, pid);
Hardcoded "(process %d)" here too.
Fixing this issue in the several spots may affect your
testsuite changes -- please be sure to rerun tests with
"target remote" afterwards.
> + }
> else
> {
> }
>
> diff --git a/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp b/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp
> index e05acb1711..616b6cf7a4 100644
> --- a/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp
> +++ b/gdb/testsuite/gdb.threads/process-dies-while-detaching.exp
> @@ -81,8 +81,15 @@ proc detach_and_expect_exit {inf_output_re test} {
> global inferior_spawn_id
> global gdb_prompt
>
> + set saw_inf_exit 0
> return_if_fail [gdb_test_multiple "detach" $test {
> - -re "Detaching from .*, process $decimal" {
> + -re "Detaching from .*, process $decimal\r\n\\\[Inferior $decimal \\(process $decimal\\) detached\\\]" {
> + }
> + # inf_output_re can also appear in the middle, so we catch
> + # this case here in order to avoid racy results.
> + -re "Detaching from .*, process $decimal\r\n${inf_output_re}\r\n\\\[Inferior $decimal \\(process $decimal\\) detached\\\]" {
> + verbose -log "saw inferior exit"
> + set saw_inf_exit 1
> }
I'm not sure I understand the need for this. If you left this
gdb_test_multiple exactly as it was before your patch, wouldn't it all
work the same?
Thanks,
Pedro Alves