Re: [PATCH 1/5] monitor: allow register hmp commands

[Greg Kurz <groug@kaod.org>]

On Tue, 22 Jun 2021 14:49:11 +0200
Gerd Hoffmann <kraxel@redhat.com> wrote:

> Allow commands having a NULL cmd pointer, add a function to set the
> pointer later.  Use case: allow modules implement hmp commands.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/monitor/monitor.h |  3 +++
>  monitor/hmp.c             |  7 +++++++
>  monitor/misc.c            | 15 +++++++++++++++
>  3 files changed, 25 insertions(+)
> 
> diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
> index 1211d6e6d69f..1a8a369b50b2 100644
> --- a/include/monitor/monitor.h
> +++ b/include/monitor/monitor.h
> @@ -51,4 +51,7 @@ int monitor_fdset_dup_fd_add(int64_t fdset_id, int flags);
>  void monitor_fdset_dup_fd_remove(int dup_fd);
>  int64_t monitor_fdset_dup_fd_find(int dup_fd);
>  
> +void monitor_register_hmp(const char *name, bool info,
> +                          void (*cmd)(Monitor *mon, const QDict *qdict));
> +
>  #endif /* MONITOR_H */
> diff --git a/monitor/hmp.c b/monitor/hmp.c
> index 6c0b33a0b19d..d50c3124e1e1 100644
> --- a/monitor/hmp.c
> +++ b/monitor/hmp.c
> @@ -1089,6 +1089,13 @@ void handle_hmp_command(MonitorHMP *mon, const char *cmdline)
>          return;
>      }
>  
> +    if (!cmd->cmd) {
> +        /* FIXME: is it useful to try autoload modules here ??? */
> +        monitor_printf(&mon->common, "Command \"%.*s\" is not available.\n",
> +                       (int)(cmdline - cmd_start), cmd_start);
> +        return;
> +    }
> +
>      qdict = monitor_parse_arguments(&mon->common, &cmdline, cmd);
>      if (!qdict) {
>          while (cmdline > cmd_start && qemu_isspace(cmdline[-1])) {
> diff --git a/monitor/misc.c b/monitor/misc.c
> index 1539e18557f0..672267008b02 100644
> --- a/monitor/misc.c
> +++ b/monitor/misc.c
> @@ -1974,6 +1974,21 @@ static void sortcmdlist(void)
>            compare_mon_cmd);
>  }
>  
> +void monitor_register_hmp(const char *name, bool info,
> +                          void (*cmd)(Monitor *mon, const QDict *qdict))
> +{
> +    HMPCommand *table = info ? hmp_info_cmds : hmp_cmds;
> +
> +    while (table->name != NULL) {
> +        if (strcmp(table->name, name) == 0) {

Would it make sense to register the same command multiple times ?
I guess it doesn't, so you may add an assert(table->cmd == NULL)
here.

> +            table->cmd = cmd;
> +            return;
> +        }
> +        table++;
> +    }
> +    g_assert_not_reached();
> +}
> +
>  void monitor_init_globals(void)
>  {
>      monitor_init_globals_core();