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Re: [Qemu-devel] [PATCH v3 2/7] hmp: Allow help on preconfig commands
From: |
Markus Armbruster |
Subject: |
Re: [Qemu-devel] [PATCH v3 2/7] hmp: Allow help on preconfig commands |
Date: |
Mon, 11 Jun 2018 15:18:22 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) |
"Dr. David Alan Gilbert" <address@hidden> writes:
> * Markus Armbruster (address@hidden) wrote:
>> "Dr. David Alan Gilbert (git)" <address@hidden> writes:
>>
>> > From: "Dr. David Alan Gilbert" <address@hidden>
>> >
>> > Allow the 'help' command in preconfig state but
>> > make it only list the preconfig commands.
>> >
>> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
>> > Reviewed-by: Peter Xu <address@hidden>
>> > Reviewed-by: Igor Mammedov <address@hidden>
>> > ---
>> > hmp-commands.hx | 1 +
>> > monitor.c | 8 +++++++-
>> > 2 files changed, 8 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/hmp-commands.hx b/hmp-commands.hx
>> > index 0734fea931..8bf590ae4b 100644
>> > --- a/hmp-commands.hx
>> > +++ b/hmp-commands.hx
>> > @@ -15,6 +15,7 @@ ETEXI
>> > .params = "[cmd]",
>> > .help = "show the help",
>> > .cmd = do_help_cmd,
>> > + .flags = "p",
>> > },
>> >
>> > STEXI
>> > diff --git a/monitor.c b/monitor.c
>> > index f4a16e6a03..31c8f5dc88 100644
>> > --- a/monitor.c
>> > +++ b/monitor.c
>> > @@ -957,6 +957,10 @@ static void help_cmd_dump_one(Monitor *mon,
>> > {
>> > int i;
>> >
>> > + if (runstate_check(RUN_STATE_PRECONFIG) && !cmd_can_preconfig(cmd)) {
>> > + return;
>> > + }
>> > +
>> > for (i = 0; i < prefix_args_nb; i++) {
>> > monitor_printf(mon, "%s ", prefix_args[i]);
>> > }
>> > @@ -979,7 +983,9 @@ static void help_cmd_dump(Monitor *mon, const
>> > mon_cmd_t *cmds,
>> >
>> > /* Find one entry to dump */
>> > for (cmd = cmds; cmd->name != NULL; cmd++) {
>> > - if (compare_cmd(args[arg_index], cmd->name)) {
>> > + if (compare_cmd(args[arg_index], cmd->name) &&
>> > + ((!runstate_check(RUN_STATE_PRECONFIG) ||
>> > + cmd_can_preconfig(cmd)))) {
>>
>> Why do we need this check in addition to the one in help_cmd_dump_one()?
>
> To gate entire subtables (we've only currently got 'info' and that's enabled,
> anyway, so it never actually triggers).
Something's bothering me around here, but I can't put a finger on it...
let me think aloud.
There's an asymmetry between command execution and help. The former has
just one check, in monitor_parse_command(). If the command has a
sub-table, and there are arguments, monitor_parse_command() recurses
into the sub-table. Thus, if the command is unavailable, the
sub-commands are unavailable as well, regardless of their "p" flags.
Help's recursion is different. It's limited to two levels, unlike
execution. help_cmd_dump_one()'s check applies to the last level.
help_cmd_dump()'s check applies to the first level. If there's just one
level, we check twice. Perhaps less than elegant, but harmless and
simple.
You can't make a sub-command available without also making the command
available. Makes sense, I guess. If you try, your "p" flags on the
sub-commands are silently ignored. That's a bit ugly, but if it doesn't
bother you, I can pretend I didn't see it ;)
> Dave
>
>> > if (cmd->sub_table) {
>> > /* continue with next arg */
>> > help_cmd_dump(mon, cmd->sub_table,
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK
[Qemu-devel] [PATCH v3 3/7] hmp: Restrict auto-complete in preconfig, Dr. David Alan Gilbert (git), 2018/06/08
[Qemu-devel] [PATCH v3 7/7] hmp: Allow HMP in preconfig state again, Dr. David Alan Gilbert (git), 2018/06/08
Re: [Qemu-devel] [PATCH v3 0/7] Reenable hmp for preconfig mode, Markus Armbruster, 2018/06/11