Patchwork [5/5] HMP: Introduce console command

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Submitter Lei Li
Date Oct. 21, 2012, 4:48 p.m.
Message ID <1350838081-6351-6-git-send-email-lilei@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/193048/
State New
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Comments

Lei Li - Oct. 21, 2012, 4:48 p.m.
Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
---
 hmp-commands.hx |   23 +++++++++++++++++++++++
 hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 hmp.h           |    1 +
 monitor.c       |   15 +++++++++++++++
 monitor.h       |    3 +++
 5 files changed, 95 insertions(+), 0 deletions(-)
Luiz Capitulino - Oct. 22, 2012, 6:59 p.m.
On Mon, 22 Oct 2012 00:48:01 +0800
Lei Li <lilei@linux.vnet.ibm.com> wrote:

> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> ---
>  hmp-commands.hx |   23 +++++++++++++++++++++++
>  hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  hmp.h           |    1 +
>  monitor.c       |   15 +++++++++++++++
>  monitor.h       |    3 +++
>  5 files changed, 95 insertions(+), 0 deletions(-)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 5f91428..f862a53 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -868,7 +868,30 @@ char device and return @var{size} of the data.
>  that specifies behavior when the queue is full/empty. By default is
>  'drop'. Note that the 'block' option is not supported now.
>          -b for 'block' option. None for 'drop' option.
> +ETEXI
> +
> +    {
> +        .name       = "console",
> +        .args_type  = "chardev:s",
> +        .params     = "chardev",
> +        .help       = "Connect to the serial console from within the"
> +                      "monitor, allow to write data to memchardev"
> +                      "'chardev'. Exit from the console and return back"
> +                      "to monitor by typing 'ctrl-]'",
> +        .mhandler.cmd = hmp_console,
> +    },
>  
> +STEXI
> +@item console @var{device}
> +@findex console
> +
> +Connect to the serial console from within the monitor, allow to write data
> +to memchardev @var{chardev}. Exit from the console and return back to
> +monitor by typing 'ctrl-]'.
> +@example
> +(qemu) console foo
> +foo: data string...
> +@end example
>  ETEXI
>  
>      {
> diff --git a/hmp.c b/hmp.c
> index fa858c4..bc245f4 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -1245,3 +1245,56 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
>      qmp_screendump(filename, &err);
>      hmp_handle_error(mon, &err);
>  }
> +
> +enum escape_char
> +{
> +    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
> +};
> +
> +static void hmp_read_console(Monitor *mon, const char *data,
> +                             void *opaque)
> +{
> +    CharDriverState *chr = opaque;
> +    uint32_t size = strlen(data);
> +    enum DataFormat format = DATA_FORMAT_UTF8;
> +    enum CongestionControl control = CONGESTION_CONTROL_DROP;
> +    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
> +
> +    Error *err = NULL;
> +
> +    if (*data == console_escape) {
> +        monitor_resume(mon);
> +        return;
> +    }
> +
> +    qmp_memchar_write(chr->label, size, data, 0, format,
> +                      0, control, &err);
> +    if (err) {
> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
> +        error_free(err);
> +        return;
> +    }

Shouldn't you also read from the device?

> +
> +    monitor_read_command(mon, 1);
> +}
> +
> +void hmp_console(Monitor *mon, const QDict *qdict)
> +{
> +    const char *device = qdict_get_str(qdict, "chardev");
> +    CharDriverState *chr;
> +    Error *err = NULL;
> +
> +    chr = qemu_chr_find(device);
> +
> +    if (!chr) {
> +        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
> +        goto out;
> +    }

No need to do this here as the QMP command will do it too.

> +
> +    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
> +        monitor_printf(mon, "Connect to console %s failed\n", device);
> +    }
> +
> +out:
> +    hmp_handle_error(mon, &err);
> +}
> diff --git a/hmp.h b/hmp.h
> index a5a0cfe..5b54a79 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -77,5 +77,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
>  void hmp_closefd(Monitor *mon, const QDict *qdict);
>  void hmp_send_key(Monitor *mon, const QDict *qdict);
>  void hmp_screen_dump(Monitor *mon, const QDict *qdict);
> +void hmp_console(Monitor *mon, const QDict *qdict);
>  
>  #endif
> diff --git a/monitor.c b/monitor.c
> index 131b325..453c084 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -256,6 +256,21 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>      }
>  }
>  
> +int monitor_read_console(Monitor *mon, const char *device,
> +                         ReadLineFunc *readline_func, void *opaque)
> +{
> +    char prompt[60];
> +
> +    if (!mon->rs) {
> +        return -1;
> +    }
> +
> +    snprintf(prompt, sizeof(prompt), "%s: ", device);
> +    readline_start(mon->rs, prompt, 0, readline_func, opaque);
> +
> +    return 0;
> +}
> +
>  void monitor_flush(Monitor *mon)
>  {
>      if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
> diff --git a/monitor.h b/monitor.h
> index b6e7d95..735bd1b 100644
> --- a/monitor.h
> +++ b/monitor.h
> @@ -86,6 +86,9 @@ ReadLineState *monitor_get_rs(Monitor *mon);
>  int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>                            void *opaque);
>  
> +int monitor_read_console(Monitor *mon, const char *device,
> +                         ReadLineFunc *readline_func, void *opaque);
> +
>  int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
>  
>  int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
Lei Li - Oct. 24, 2012, 7:17 a.m.
On 10/23/2012 02:59 AM, Luiz Capitulino wrote:
> On Mon, 22 Oct 2012 00:48:01 +0800
> Lei Li <lilei@linux.vnet.ibm.com> wrote:
>
>> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
>> ---
>>   hmp-commands.hx |   23 +++++++++++++++++++++++
>>   hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>   hmp.h           |    1 +
>>   monitor.c       |   15 +++++++++++++++
>>   monitor.h       |    3 +++
>>   5 files changed, 95 insertions(+), 0 deletions(-)
>>
>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>> index 5f91428..f862a53 100644
>> --- a/hmp-commands.hx
>> +++ b/hmp-commands.hx
>> @@ -868,7 +868,30 @@ char device and return @var{size} of the data.
>>   that specifies behavior when the queue is full/empty. By default is
>>   'drop'. Note that the 'block' option is not supported now.
>>           -b for 'block' option. None for 'drop' option.
>> +ETEXI
>> +
>> +    {
>> +        .name       = "console",
>> +        .args_type  = "chardev:s",
>> +        .params     = "chardev",
>> +        .help       = "Connect to the serial console from within the"
>> +                      "monitor, allow to write data to memchardev"
>> +                      "'chardev'. Exit from the console and return back"
>> +                      "to monitor by typing 'ctrl-]'",
>> +        .mhandler.cmd = hmp_console,
>> +    },
>>   
>> +STEXI
>> +@item console @var{device}
>> +@findex console
>> +
>> +Connect to the serial console from within the monitor, allow to write data
>> +to memchardev @var{chardev}. Exit from the console and return back to
>> +monitor by typing 'ctrl-]'.
>> +@example
>> +(qemu) console foo
>> +foo: data string...
>> +@end example
>>   ETEXI
>>   
>>       {
>> diff --git a/hmp.c b/hmp.c
>> index fa858c4..bc245f4 100644
>> --- a/hmp.c
>> +++ b/hmp.c
>> @@ -1245,3 +1245,56 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
>>       qmp_screendump(filename, &err);
>>       hmp_handle_error(mon, &err);
>>   }
>> +
>> +enum escape_char
>> +{
>> +    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
>> +};
>> +
>> +static void hmp_read_console(Monitor *mon, const char *data,
>> +                             void *opaque)
>> +{
>> +    CharDriverState *chr = opaque;
>> +    uint32_t size = strlen(data);
>> +    enum DataFormat format = DATA_FORMAT_UTF8;
>> +    enum CongestionControl control = CONGESTION_CONTROL_DROP;
>> +    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
>> +
>> +    Error *err = NULL;
>> +
>> +    if (*data == console_escape) {
>> +        monitor_resume(mon);
>> +        return;
>> +    }
>> +
>> +    qmp_memchar_write(chr->label, size, data, 0, format,
>> +                      0, control, &err);
>> +    if (err) {
>> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
>> +        error_free(err);
>> +        return;
>> +    }
> Shouldn't you also read from the device?

The use-case for this console command is just allow the user to
write data to each memchar device as in a signal terminal. Then
type escape sequences to take you back to the monitor. So I don't
think it is also need to read from the device in this command.

BTW, we can read from the device by hmp_memchar_read. :)

>> +
>> +    monitor_read_command(mon, 1);
>> +}
>> +
>> +void hmp_console(Monitor *mon, const QDict *qdict)
>> +{
>> +    const char *device = qdict_get_str(qdict, "chardev");
>> +    CharDriverState *chr;
>> +    Error *err = NULL;
>> +
>> +    chr = qemu_chr_find(device);
>> +
>> +    if (!chr) {
>> +        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
>> +        goto out;
>> +    }
> No need to do this here as the QMP command will do it too.
>
I think we should do this check here, otherwise would
cause core dump when 'console' to a chardev that does not
exist. Wepass parameterchr->label by qmp_memchar_write()
in the handler hmp_read_console.

>> +
>> +    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
>> +        monitor_printf(mon, "Connect to console %s failed\n", device);
>> +    }
>> +
>> +out:
>> +    hmp_handle_error(mon, &err);
>> +}
>> diff --git a/hmp.h b/hmp.h
>> index a5a0cfe..5b54a79 100644
>> --- a/hmp.h
>> +++ b/hmp.h
>> @@ -77,5 +77,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
>>   void hmp_closefd(Monitor *mon, const QDict *qdict);
>>   void hmp_send_key(Monitor *mon, const QDict *qdict);
>>   void hmp_screen_dump(Monitor *mon, const QDict *qdict);
>> +void hmp_console(Monitor *mon, const QDict *qdict);
>>   
>>   #endif
>> diff --git a/monitor.c b/monitor.c
>> index 131b325..453c084 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -256,6 +256,21 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>>       }
>>   }
>>   
>> +int monitor_read_console(Monitor *mon, const char *device,
>> +                         ReadLineFunc *readline_func, void *opaque)
>> +{
>> +    char prompt[60];
>> +
>> +    if (!mon->rs) {
>> +        return -1;
>> +    }
>> +
>> +    snprintf(prompt, sizeof(prompt), "%s: ", device);
>> +    readline_start(mon->rs, prompt, 0, readline_func, opaque);
>> +
>> +    return 0;
>> +}
>> +
>>   void monitor_flush(Monitor *mon)
>>   {
>>       if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
>> diff --git a/monitor.h b/monitor.h
>> index b6e7d95..735bd1b 100644
>> --- a/monitor.h
>> +++ b/monitor.h
>> @@ -86,6 +86,9 @@ ReadLineState *monitor_get_rs(Monitor *mon);
>>   int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>>                             void *opaque);
>>   
>> +int monitor_read_console(Monitor *mon, const char *device,
>> +                         ReadLineFunc *readline_func, void *opaque);
>> +
>>   int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
>>   
>>   int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
>
Luiz Capitulino - Oct. 24, 2012, 12:55 p.m.
On Wed, 24 Oct 2012 15:17:21 +0800
Lei Li <lilei@linux.vnet.ibm.com> wrote:

> On 10/23/2012 02:59 AM, Luiz Capitulino wrote:
> > On Mon, 22 Oct 2012 00:48:01 +0800
> > Lei Li <lilei@linux.vnet.ibm.com> wrote:
> >
> >> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> >> ---
> >>   hmp-commands.hx |   23 +++++++++++++++++++++++
> >>   hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>   hmp.h           |    1 +
> >>   monitor.c       |   15 +++++++++++++++
> >>   monitor.h       |    3 +++
> >>   5 files changed, 95 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/hmp-commands.hx b/hmp-commands.hx
> >> index 5f91428..f862a53 100644
> >> --- a/hmp-commands.hx
> >> +++ b/hmp-commands.hx
> >> @@ -868,7 +868,30 @@ char device and return @var{size} of the data.
> >>   that specifies behavior when the queue is full/empty. By default is
> >>   'drop'. Note that the 'block' option is not supported now.
> >>           -b for 'block' option. None for 'drop' option.
> >> +ETEXI
> >> +
> >> +    {
> >> +        .name       = "console",
> >> +        .args_type  = "chardev:s",
> >> +        .params     = "chardev",
> >> +        .help       = "Connect to the serial console from within the"
> >> +                      "monitor, allow to write data to memchardev"
> >> +                      "'chardev'. Exit from the console and return back"
> >> +                      "to monitor by typing 'ctrl-]'",
> >> +        .mhandler.cmd = hmp_console,
> >> +    },
> >>   
> >> +STEXI
> >> +@item console @var{device}
> >> +@findex console
> >> +
> >> +Connect to the serial console from within the monitor, allow to write data
> >> +to memchardev @var{chardev}. Exit from the console and return back to
> >> +monitor by typing 'ctrl-]'.
> >> +@example
> >> +(qemu) console foo
> >> +foo: data string...
> >> +@end example
> >>   ETEXI
> >>   
> >>       {
> >> diff --git a/hmp.c b/hmp.c
> >> index fa858c4..bc245f4 100644
> >> --- a/hmp.c
> >> +++ b/hmp.c
> >> @@ -1245,3 +1245,56 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
> >>       qmp_screendump(filename, &err);
> >>       hmp_handle_error(mon, &err);
> >>   }
> >> +
> >> +enum escape_char
> >> +{
> >> +    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
> >> +};
> >> +
> >> +static void hmp_read_console(Monitor *mon, const char *data,
> >> +                             void *opaque)
> >> +{
> >> +    CharDriverState *chr = opaque;
> >> +    uint32_t size = strlen(data);
> >> +    enum DataFormat format = DATA_FORMAT_UTF8;
> >> +    enum CongestionControl control = CONGESTION_CONTROL_DROP;
> >> +    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
> >> +
> >> +    Error *err = NULL;
> >> +
> >> +    if (*data == console_escape) {
> >> +        monitor_resume(mon);
> >> +        return;
> >> +    }
> >> +
> >> +    qmp_memchar_write(chr->label, size, data, 0, format,
> >> +                      0, control, &err);
> >> +    if (err) {
> >> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
> >> +        error_free(err);
> >> +        return;
> >> +    }
> > Shouldn't you also read from the device?
> 
> The use-case for this console command is just allow the user to
> write data to each memchar device as in a signal terminal. Then
> type escape sequences to take you back to the monitor. So I don't
> think it is also need to read from the device in this command.
> 
> BTW, we can read from the device by hmp_memchar_read. :)

And how is the console command better than the hmp_memchar_write one?

Could you please give examples?

> >> +
> >> +    monitor_read_command(mon, 1);
> >> +}
> >> +
> >> +void hmp_console(Monitor *mon, const QDict *qdict)
> >> +{
> >> +    const char *device = qdict_get_str(qdict, "chardev");
> >> +    CharDriverState *chr;
> >> +    Error *err = NULL;
> >> +
> >> +    chr = qemu_chr_find(device);
> >> +
> >> +    if (!chr) {
> >> +        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
> >> +        goto out;
> >> +    }
> > No need to do this here as the QMP command will do it too.
> >
> I think we should do this check here, otherwise would
> cause core dump when 'console' to a chardev that does not
> exist. Wepass parameterchr->label by qmp_memchar_write()
> in the handler hmp_read_console.

Do you need the chr object? Why don't you just pass 'device' to
monitor_read_console()?

> 
> >> +
> >> +    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
> >> +        monitor_printf(mon, "Connect to console %s failed\n", device);
> >> +    }
> >> +
> >> +out:
> >> +    hmp_handle_error(mon, &err);
> >> +}
> >> diff --git a/hmp.h b/hmp.h
> >> index a5a0cfe..5b54a79 100644
> >> --- a/hmp.h
> >> +++ b/hmp.h
> >> @@ -77,5 +77,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
> >>   void hmp_closefd(Monitor *mon, const QDict *qdict);
> >>   void hmp_send_key(Monitor *mon, const QDict *qdict);
> >>   void hmp_screen_dump(Monitor *mon, const QDict *qdict);
> >> +void hmp_console(Monitor *mon, const QDict *qdict);
> >>   
> >>   #endif
> >> diff --git a/monitor.c b/monitor.c
> >> index 131b325..453c084 100644
> >> --- a/monitor.c
> >> +++ b/monitor.c
> >> @@ -256,6 +256,21 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
> >>       }
> >>   }
> >>   
> >> +int monitor_read_console(Monitor *mon, const char *device,
> >> +                         ReadLineFunc *readline_func, void *opaque)
> >> +{
> >> +    char prompt[60];
> >> +
> >> +    if (!mon->rs) {
> >> +        return -1;
> >> +    }
> >> +
> >> +    snprintf(prompt, sizeof(prompt), "%s: ", device);
> >> +    readline_start(mon->rs, prompt, 0, readline_func, opaque);
> >> +
> >> +    return 0;
> >> +}
> >> +
> >>   void monitor_flush(Monitor *mon)
> >>   {
> >>       if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
> >> diff --git a/monitor.h b/monitor.h
> >> index b6e7d95..735bd1b 100644
> >> --- a/monitor.h
> >> +++ b/monitor.h
> >> @@ -86,6 +86,9 @@ ReadLineState *monitor_get_rs(Monitor *mon);
> >>   int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
> >>                             void *opaque);
> >>   
> >> +int monitor_read_console(Monitor *mon, const char *device,
> >> +                         ReadLineFunc *readline_func, void *opaque);
> >> +
> >>   int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
> >>   
> >>   int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
> >
> 
>
Lei Li - Oct. 25, 2012, 7:43 p.m.
On 10/24/2012 08:55 PM, Luiz Capitulino wrote:
> On Wed, 24 Oct 2012 15:17:21 +0800
> Lei Li <lilei@linux.vnet.ibm.com> wrote:
>
>> On 10/23/2012 02:59 AM, Luiz Capitulino wrote:
>>> On Mon, 22 Oct 2012 00:48:01 +0800
>>> Lei Li <lilei@linux.vnet.ibm.com> wrote:
>>>
>>>> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
>>>> ---
>>>>    hmp-commands.hx |   23 +++++++++++++++++++++++
>>>>    hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>    hmp.h           |    1 +
>>>>    monitor.c       |   15 +++++++++++++++
>>>>    monitor.h       |    3 +++
>>>>    5 files changed, 95 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/hmp-commands.hx b/hmp-commands.hx
>>>> index 5f91428..f862a53 100644
>>>> --- a/hmp-commands.hx
>>>> +++ b/hmp-commands.hx
>>>> @@ -868,7 +868,30 @@ char device and return @var{size} of the data.
>>>>    that specifies behavior when the queue is full/empty. By default is
>>>>    'drop'. Note that the 'block' option is not supported now.
>>>>            -b for 'block' option. None for 'drop' option.
>>>> +ETEXI
>>>> +
>>>> +    {
>>>> +        .name       = "console",
>>>> +        .args_type  = "chardev:s",
>>>> +        .params     = "chardev",
>>>> +        .help       = "Connect to the serial console from within the"
>>>> +                      "monitor, allow to write data to memchardev"
>>>> +                      "'chardev'. Exit from the console and return back"
>>>> +                      "to monitor by typing 'ctrl-]'",
>>>> +        .mhandler.cmd = hmp_console,
>>>> +    },
>>>>    
>>>> +STEXI
>>>> +@item console @var{device}
>>>> +@findex console
>>>> +
>>>> +Connect to the serial console from within the monitor, allow to write data
>>>> +to memchardev @var{chardev}. Exit from the console and return back to
>>>> +monitor by typing 'ctrl-]'.
>>>> +@example
>>>> +(qemu) console foo
>>>> +foo: data string...
>>>> +@end example
>>>>    ETEXI
>>>>    
>>>>        {
>>>> diff --git a/hmp.c b/hmp.c
>>>> index fa858c4..bc245f4 100644
>>>> --- a/hmp.c
>>>> +++ b/hmp.c
>>>> @@ -1245,3 +1245,56 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
>>>>        qmp_screendump(filename, &err);
>>>>        hmp_handle_error(mon, &err);
>>>>    }
>>>> +
>>>> +enum escape_char
>>>> +{
>>>> +    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
>>>> +};
>>>> +
>>>> +static void hmp_read_console(Monitor *mon, const char *data,
>>>> +                             void *opaque)
>>>> +{
>>>> +    CharDriverState *chr = opaque;
>>>> +    uint32_t size = strlen(data);
>>>> +    enum DataFormat format = DATA_FORMAT_UTF8;
>>>> +    enum CongestionControl control = CONGESTION_CONTROL_DROP;
>>>> +    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
>>>> +
>>>> +    Error *err = NULL;
>>>> +
>>>> +    if (*data == console_escape) {
>>>> +        monitor_resume(mon);
>>>> +        return;
>>>> +    }
>>>> +
>>>> +    qmp_memchar_write(chr->label, size, data, 0, format,
>>>> +                      0, control, &err);
>>>> +    if (err) {
>>>> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
>>>> +        error_free(err);
>>>> +        return;
>>>> +    }
>>> Shouldn't you also read from the device?
>> The use-case for this console command is just allow the user to
>> write data to each memchar device as in a signal terminal. Then
>> type escape sequences to take you back to the monitor. So I don't
>> think it is also need to read from the device in this command.
>>
>> BTW, we can read from the device by hmp_memchar_read. :)
> And how is the console command better than the hmp_memchar_write one?
>
> Could you please give examples?

Sure. The "console" command behaves like:

(qemu) console foo
foo: hello world
(qemu)

you can input data, then put enter or ctrl-] to return back to
the monitor. The data input from console would be written to the
CirMemCharDriver backend, which provide a more friendly and nice
HMP command as Anthony suggested.


>
>>>> +
>>>> +    monitor_read_command(mon, 1);
>>>> +}
>>>> +
>>>> +void hmp_console(Monitor *mon, const QDict *qdict)
>>>> +{
>>>> +    const char *device = qdict_get_str(qdict, "chardev");
>>>> +    CharDriverState *chr;
>>>> +    Error *err = NULL;
>>>> +
>>>> +    chr = qemu_chr_find(device);
>>>> +
>>>> +    if (!chr) {
>>>> +        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
>>>> +        goto out;
>>>> +    }
>>> No need to do this here as the QMP command will do it too.
>>>
>> I think we should do this check here, otherwise would
>> cause core dump when 'console' to a chardev that does not
>> exist. Wepass parameterchr->label by qmp_memchar_write()
>> in the handler hmp_read_console.
> Do you need the chr object? Why don't you just pass 'device' to
> monitor_read_console()?

Yes, we need 'device' and 'chr' both here. 'device' pass to monitor_read_console
for the friendly prompt. 'chr' pass to handler hmp_read_console, the reason did not
pass 'device' directly to it is the limitation of argument for the handler
hmp_read_console. Also it's better to give the prompt before the user enter the input
console if the device not found, the use-case as I post above.

>>>> +
>>>> +    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
>>>> +        monitor_printf(mon, "Connect to console %s failed\n", device);
>>>> +    }
>>>> +
>>>> +out:
>>>> +    hmp_handle_error(mon, &err);
>>>> +}
>>>> diff --git a/hmp.h b/hmp.h
>>>> index a5a0cfe..5b54a79 100644
>>>> --- a/hmp.h
>>>> +++ b/hmp.h
>>>> @@ -77,5 +77,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
>>>>    void hmp_closefd(Monitor *mon, const QDict *qdict);
>>>>    void hmp_send_key(Monitor *mon, const QDict *qdict);
>>>>    void hmp_screen_dump(Monitor *mon, const QDict *qdict);
>>>> +void hmp_console(Monitor *mon, const QDict *qdict);
>>>>    
>>>>    #endif
>>>> diff --git a/monitor.c b/monitor.c
>>>> index 131b325..453c084 100644
>>>> --- a/monitor.c
>>>> +++ b/monitor.c
>>>> @@ -256,6 +256,21 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>>>>        }
>>>>    }
>>>>    
>>>> +int monitor_read_console(Monitor *mon, const char *device,
>>>> +                         ReadLineFunc *readline_func, void *opaque)
>>>> +{
>>>> +    char prompt[60];
>>>> +
>>>> +    if (!mon->rs) {
>>>> +        return -1;
>>>> +    }
>>>> +
>>>> +    snprintf(prompt, sizeof(prompt), "%s: ", device);
>>>> +    readline_start(mon->rs, prompt, 0, readline_func, opaque);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>>    void monitor_flush(Monitor *mon)
>>>>    {
>>>>        if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
>>>> diff --git a/monitor.h b/monitor.h
>>>> index b6e7d95..735bd1b 100644
>>>> --- a/monitor.h
>>>> +++ b/monitor.h
>>>> @@ -86,6 +86,9 @@ ReadLineState *monitor_get_rs(Monitor *mon);
>>>>    int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
>>>>                              void *opaque);
>>>>    
>>>> +int monitor_read_console(Monitor *mon, const char *device,
>>>> +                         ReadLineFunc *readline_func, void *opaque);
>>>> +
>>>>    int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
>>>>    
>>>>    int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
>>
>
Luiz Capitulino - Oct. 26, 2012, 1:56 p.m.
On Fri, 26 Oct 2012 03:43:10 +0800
Lei Li <lilei@linux.vnet.ibm.com> wrote:

> On 10/24/2012 08:55 PM, Luiz Capitulino wrote:
> > On Wed, 24 Oct 2012 15:17:21 +0800
> > Lei Li <lilei@linux.vnet.ibm.com> wrote:
> >
> >> On 10/23/2012 02:59 AM, Luiz Capitulino wrote:
> >>> On Mon, 22 Oct 2012 00:48:01 +0800
> >>> Lei Li <lilei@linux.vnet.ibm.com> wrote:
> >>>
> >>>> Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
> >>>> ---
> >>>>    hmp-commands.hx |   23 +++++++++++++++++++++++
> >>>>    hmp.c           |   53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>>>    hmp.h           |    1 +
> >>>>    monitor.c       |   15 +++++++++++++++
> >>>>    monitor.h       |    3 +++
> >>>>    5 files changed, 95 insertions(+), 0 deletions(-)
> >>>>
> >>>> diff --git a/hmp-commands.hx b/hmp-commands.hx
> >>>> index 5f91428..f862a53 100644
> >>>> --- a/hmp-commands.hx
> >>>> +++ b/hmp-commands.hx
> >>>> @@ -868,7 +868,30 @@ char device and return @var{size} of the data.
> >>>>    that specifies behavior when the queue is full/empty. By default is
> >>>>    'drop'. Note that the 'block' option is not supported now.
> >>>>            -b for 'block' option. None for 'drop' option.
> >>>> +ETEXI
> >>>> +
> >>>> +    {
> >>>> +        .name       = "console",
> >>>> +        .args_type  = "chardev:s",
> >>>> +        .params     = "chardev",
> >>>> +        .help       = "Connect to the serial console from within the"
> >>>> +                      "monitor, allow to write data to memchardev"
> >>>> +                      "'chardev'. Exit from the console and return back"
> >>>> +                      "to monitor by typing 'ctrl-]'",
> >>>> +        .mhandler.cmd = hmp_console,
> >>>> +    },
> >>>>    
> >>>> +STEXI
> >>>> +@item console @var{device}
> >>>> +@findex console
> >>>> +
> >>>> +Connect to the serial console from within the monitor, allow to write data
> >>>> +to memchardev @var{chardev}. Exit from the console and return back to
> >>>> +monitor by typing 'ctrl-]'.
> >>>> +@example
> >>>> +(qemu) console foo
> >>>> +foo: data string...
> >>>> +@end example
> >>>>    ETEXI
> >>>>    
> >>>>        {
> >>>> diff --git a/hmp.c b/hmp.c
> >>>> index fa858c4..bc245f4 100644
> >>>> --- a/hmp.c
> >>>> +++ b/hmp.c
> >>>> @@ -1245,3 +1245,56 @@ void hmp_screen_dump(Monitor *mon, const QDict *qdict)
> >>>>        qmp_screendump(filename, &err);
> >>>>        hmp_handle_error(mon, &err);
> >>>>    }
> >>>> +
> >>>> +enum escape_char
> >>>> +{
> >>>> +    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
> >>>> +};
> >>>> +
> >>>> +static void hmp_read_console(Monitor *mon, const char *data,
> >>>> +                             void *opaque)
> >>>> +{
> >>>> +    CharDriverState *chr = opaque;
> >>>> +    uint32_t size = strlen(data);
> >>>> +    enum DataFormat format = DATA_FORMAT_UTF8;
> >>>> +    enum CongestionControl control = CONGESTION_CONTROL_DROP;
> >>>> +    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
> >>>> +
> >>>> +    Error *err = NULL;
> >>>> +
> >>>> +    if (*data == console_escape) {
> >>>> +        monitor_resume(mon);
> >>>> +        return;
> >>>> +    }
> >>>> +
> >>>> +    qmp_memchar_write(chr->label, size, data, 0, format,
> >>>> +                      0, control, &err);
> >>>> +    if (err) {
> >>>> +        monitor_printf(mon, "%s\n", error_get_pretty(err));
> >>>> +        error_free(err);
> >>>> +        return;
> >>>> +    }
> >>> Shouldn't you also read from the device?
> >> The use-case for this console command is just allow the user to
> >> write data to each memchar device as in a signal terminal. Then
> >> type escape sequences to take you back to the monitor. So I don't
> >> think it is also need to read from the device in this command.
> >>
> >> BTW, we can read from the device by hmp_memchar_read. :)
> > And how is the console command better than the hmp_memchar_write one?
> >
> > Could you please give examples?
> 
> Sure. The "console" command behaves like:
> 
> (qemu) console foo
> foo: hello world
> (qemu)
> 
> you can input data, then put enter or ctrl-] to return back to
> the monitor. The data input from console would be written to the
> CirMemCharDriver backend, which provide a more friendly and nice
> HMP command as Anthony suggested.

Maybe I'm missing something, but I don't understand how this is
better than the hmp_memchar_write command.

> >>>> +
> >>>> +    monitor_read_command(mon, 1);
> >>>> +}
> >>>> +
> >>>> +void hmp_console(Monitor *mon, const QDict *qdict)
> >>>> +{
> >>>> +    const char *device = qdict_get_str(qdict, "chardev");
> >>>> +    CharDriverState *chr;
> >>>> +    Error *err = NULL;
> >>>> +
> >>>> +    chr = qemu_chr_find(device);
> >>>> +
> >>>> +    if (!chr) {
> >>>> +        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
> >>>> +        goto out;
> >>>> +    }
> >>> No need to do this here as the QMP command will do it too.
> >>>
> >> I think we should do this check here, otherwise would
> >> cause core dump when 'console' to a chardev that does not
> >> exist. Wepass parameterchr->label by qmp_memchar_write()
> >> in the handler hmp_read_console.
> > Do you need the chr object? Why don't you just pass 'device' to
> > monitor_read_console()?
> 
> Yes, we need 'device' and 'chr' both here. 'device' pass to monitor_read_console
> for the friendly prompt. 'chr' pass to handler hmp_read_console, the reason did not
> pass 'device' directly to it is the limitation of argument for the handler
> hmp_read_console.

What limitation? It takes 'data' and 'opaque' (which is a bit weird).

> Also it's better to give the prompt before the user enter the input
> console if the device not found, the use-case as I post above.

Why?

> 
> >>>> +
> >>>> +    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
> >>>> +        monitor_printf(mon, "Connect to console %s failed\n", device);
> >>>> +    }
> >>>> +
> >>>> +out:
> >>>> +    hmp_handle_error(mon, &err);
> >>>> +}
> >>>> diff --git a/hmp.h b/hmp.h
> >>>> index a5a0cfe..5b54a79 100644
> >>>> --- a/hmp.h
> >>>> +++ b/hmp.h
> >>>> @@ -77,5 +77,6 @@ void hmp_getfd(Monitor *mon, const QDict *qdict);
> >>>>    void hmp_closefd(Monitor *mon, const QDict *qdict);
> >>>>    void hmp_send_key(Monitor *mon, const QDict *qdict);
> >>>>    void hmp_screen_dump(Monitor *mon, const QDict *qdict);
> >>>> +void hmp_console(Monitor *mon, const QDict *qdict);
> >>>>    
> >>>>    #endif
> >>>> diff --git a/monitor.c b/monitor.c
> >>>> index 131b325..453c084 100644
> >>>> --- a/monitor.c
> >>>> +++ b/monitor.c
> >>>> @@ -256,6 +256,21 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
> >>>>        }
> >>>>    }
> >>>>    
> >>>> +int monitor_read_console(Monitor *mon, const char *device,
> >>>> +                         ReadLineFunc *readline_func, void *opaque)
> >>>> +{
> >>>> +    char prompt[60];
> >>>> +
> >>>> +    if (!mon->rs) {
> >>>> +        return -1;
> >>>> +    }
> >>>> +
> >>>> +    snprintf(prompt, sizeof(prompt), "%s: ", device);
> >>>> +    readline_start(mon->rs, prompt, 0, readline_func, opaque);
> >>>> +
> >>>> +    return 0;
> >>>> +}
> >>>> +
> >>>>    void monitor_flush(Monitor *mon)
> >>>>    {
> >>>>        if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
> >>>> diff --git a/monitor.h b/monitor.h
> >>>> index b6e7d95..735bd1b 100644
> >>>> --- a/monitor.h
> >>>> +++ b/monitor.h
> >>>> @@ -86,6 +86,9 @@ ReadLineState *monitor_get_rs(Monitor *mon);
> >>>>    int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
> >>>>                              void *opaque);
> >>>>    
> >>>> +int monitor_read_console(Monitor *mon, const char *device,
> >>>> +                         ReadLineFunc *readline_func, void *opaque);
> >>>> +
> >>>>    int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
> >>>>    
> >>>>    int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);
> >>
> >
> 
>

Patch

diff --git a/hmp-commands.hx b/hmp-commands.hx
index 5f91428..f862a53 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -868,7 +868,30 @@  char device and return @var{size} of the data.
 that specifies behavior when the queue is full/empty. By default is
 'drop'. Note that the 'block' option is not supported now.
         -b for 'block' option. None for 'drop' option.
+ETEXI
+
+    {
+        .name       = "console",
+        .args_type  = "chardev:s",
+        .params     = "chardev",
+        .help       = "Connect to the serial console from within the"
+                      "monitor, allow to write data to memchardev"
+                      "'chardev'. Exit from the console and return back"
+                      "to monitor by typing 'ctrl-]'",
+        .mhandler.cmd = hmp_console,
+    },
 
+STEXI
+@item console @var{device}
+@findex console
+
+Connect to the serial console from within the monitor, allow to write data
+to memchardev @var{chardev}. Exit from the console and return back to
+monitor by typing 'ctrl-]'.
+@example
+(qemu) console foo
+foo: data string...
+@end example
 ETEXI
 
     {
diff --git a/hmp.c b/hmp.c
index fa858c4..bc245f4 100644
--- a/hmp.c
+++ b/hmp.c
@@ -1245,3 +1245,56 @@  void hmp_screen_dump(Monitor *mon, const QDict *qdict)
     qmp_screendump(filename, &err);
     hmp_handle_error(mon, &err);
 }
+
+enum escape_char
+{
+    ESCAPE_CHAR_CTRL_GS = 0x1d  /* ctrl-] used for escape */
+};
+
+static void hmp_read_console(Monitor *mon, const char *data,
+                             void *opaque)
+{
+    CharDriverState *chr = opaque;
+    uint32_t size = strlen(data);
+    enum DataFormat format = DATA_FORMAT_UTF8;
+    enum CongestionControl control = CONGESTION_CONTROL_DROP;
+    enum escape_char console_escape = ESCAPE_CHAR_CTRL_GS;
+
+    Error *err = NULL;
+
+    if (*data == console_escape) {
+        monitor_resume(mon);
+        return;
+    }
+
+    qmp_memchar_write(chr->label, size, data, 0, format,
+                      0, control, &err);
+    if (err) {
+        monitor_printf(mon, "%s\n", error_get_pretty(err));
+        error_free(err);
+        return;
+    }
+
+    monitor_read_command(mon, 1);
+}
+
+void hmp_console(Monitor *mon, const QDict *qdict)
+{
+    const char *device = qdict_get_str(qdict, "chardev");
+    CharDriverState *chr;
+    Error *err = NULL;
+
+    chr = qemu_chr_find(device);
+
+    if (!chr) {
+        error_set(&err, QERR_DEVICE_NOT_FOUND, device);
+        goto out;
+    }
+
+    if (monitor_read_console(mon, device, hmp_read_console, chr) < 0) {
+        monitor_printf(mon, "Connect to console %s failed\n", device);
+    }
+
+out:
+    hmp_handle_error(mon, &err);
+}
diff --git a/hmp.h b/hmp.h
index a5a0cfe..5b54a79 100644
--- a/hmp.h
+++ b/hmp.h
@@ -77,5 +77,6 @@  void hmp_getfd(Monitor *mon, const QDict *qdict);
 void hmp_closefd(Monitor *mon, const QDict *qdict);
 void hmp_send_key(Monitor *mon, const QDict *qdict);
 void hmp_screen_dump(Monitor *mon, const QDict *qdict);
+void hmp_console(Monitor *mon, const QDict *qdict);
 
 #endif
diff --git a/monitor.c b/monitor.c
index 131b325..453c084 100644
--- a/monitor.c
+++ b/monitor.c
@@ -256,6 +256,21 @@  int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
     }
 }
 
+int monitor_read_console(Monitor *mon, const char *device,
+                         ReadLineFunc *readline_func, void *opaque)
+{
+    char prompt[60];
+
+    if (!mon->rs) {
+        return -1;
+    }
+
+    snprintf(prompt, sizeof(prompt), "%s: ", device);
+    readline_start(mon->rs, prompt, 0, readline_func, opaque);
+
+    return 0;
+}
+
 void monitor_flush(Monitor *mon)
 {
     if (mon && mon->outbuf_index != 0 && !mon->mux_out) {
diff --git a/monitor.h b/monitor.h
index b6e7d95..735bd1b 100644
--- a/monitor.h
+++ b/monitor.h
@@ -86,6 +86,9 @@  ReadLineState *monitor_get_rs(Monitor *mon);
 int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
                           void *opaque);
 
+int monitor_read_console(Monitor *mon, const char *device,
+                         ReadLineFunc *readline_func, void *opaque);
+
 int qmp_qom_set(Monitor *mon, const QDict *qdict, QObject **ret);
 
 int qmp_qom_get(Monitor *mon, const QDict *qdict, QObject **ret);