Re: [PATCH v3 1/1] monitor/hmp: print trace as option in help for log command

[Markus Armbruster]

Dongli Zhang <dongli.zhang@oracle.com> writes:

> The below is printed when printing help information in qemu-system-x86_64
> command line, and when CONFIG_TRACE_LOG is enabled:
>
> ----------------------------
> $ qemu-system-x86_64 -d help
> ... ...
> trace:PATTERN   enable trace events
>
> Use "-d trace:help" to get a list of trace events.
> ----------------------------
>
> However, the options of "trace:PATTERN" are only printed by
> "qemu-system-x86_64 -d help", but missing in hmp "help log" command.
>
> Fixes: c84ea00dc2 ("log: add "-d trace:PATTERN"")
> Cc: Joe Jin <joe.jin@oracle.com>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
> Changed since v1:
> - change format for "none" as well.
> Changed since v2:
> - use "log trace:help" in help message.
> - add more clarification in commit message.
> - add 'Fixes' tag.
> ---
>  monitor/hmp.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/monitor/hmp.c b/monitor/hmp.c
> index 15ca04735c..a3375d0341 100644
> --- a/monitor/hmp.c
> +++ b/monitor/hmp.c
> @@ -285,10 +285,15 @@ void help_cmd(Monitor *mon, const char *name)
>          if (!strcmp(name, "log")) {
>              const QEMULogItem *item;
>              monitor_printf(mon, "Log items (comma separated):\n");
> -            monitor_printf(mon, "%-10s %s\n", "none", "remove all logs");
> +            monitor_printf(mon, "%-15s %s\n", "none", "remove all logs");
>              for (item = qemu_log_items; item->mask != 0; item++) {
> -                monitor_printf(mon, "%-10s %s\n", item->name, item->help);
> +                monitor_printf(mon, "%-15s %s\n", item->name, item->help);
>              }
> +#ifdef CONFIG_TRACE_LOG
> +            monitor_printf(mon, "trace:PATTERN   enable trace events\n");
> +            monitor_printf(mon, "\nUse \"log trace:help\" to get a list of "
> +                           "trace events.\n\n");
> +#endif
>              return;
>          }

Reviewed-by: Markus Armbruster <armbru@redhat.com>

Not this patch's fault:

1. "-d help" terminates with exit status 1, "-d trace:help" with 0.  The
   former is wrong.

2. HMP "log trace:help" prints to stdout instead of the current monitor.

3. Output of HMP "log trace:help" sometimes is truncated for me.

4. Output of "log trace:help" and "info trace-events" is unwieldy.
   Sorted output could be a bit less unwieldy.

5. Could "log trace:help" and "info trace-events" share code?