Re: [Qemu-devel] [PATCH 2/3] qmp: qmp_send_key(): accept key codes in hex

[Luiz Capitulino]

On Thu, 27 Sep 2012 13:42:57 +0200
Markus Armbruster <address@hidden> wrote:

> Luiz Capitulino <address@hidden> writes:
> 
> > Before the qapi conversion, the sendkey command could be used to
> > send key codes in hex directly to the guest. In HMP, this would
> > be like:
> >
> >  (qemu) sendkey 0xdc
> >
> > However, the qapi conversion broke this, as it only supports sending
> > QKeyCode values to the guest. That's a regression.
> 
> Let me elaborate, to make sure I got it.
> 
> Before the QAPI conversion, sendkey used get_keycode() to convert key
> substrings to integer key codes.  Source code:
> 
>     static int get_keycode(const char *key)
>     {
>         const KeyDef *p;
>         char *endp;
>         int ret;
> 
>         for(p = key_defs; p->name != NULL; p++) {
>             if (!strcmp(key, p->name))
>                 return p->keycode;
>         }
>         if (strstart(key, "0x", NULL)) {
>             ret = strtoul(key, &endp, 0);
>             if (*endp == '\0' && ret >= 0x01 && ret <= 0xff)
>                 return ret;
>         }
>         return -1;
>     }
> 
> If @key is a recognized key name, return its (positive) code.
> Else, if @key is a hexadecimal number between 1 and 0xff, return the
> number.
> Else, return -1.
> 
> Since the QAPI conversion, it uses index_from_key():
> 
>     int index_from_key(const char *key)
>     {
>         int i, keycode;
>         char *endp;
> 
>         for (i = 0; QKeyCode_lookup[i] != NULL; i++) {
>             if (!strcmp(key, QKeyCode_lookup[i])) {
>                 break;
>             }
>         }
> 
>         if (strstart(key, "0x", NULL)) {
>             keycode = strtoul(key, &endp, 0);
>             if (*endp == '\0' && keycode >= 0x01 && keycode <= 0xff) {
>                 for (i = 0; i < Q_KEY_CODE_MAX; i++) {
>                     if (keycode == key_defs[i]) {
>                         break;
>                     }
>                 }
>             }
>         }
> 
>         /* Return Q_KEY_CODE_MAX if the key is invalid */
>         return i;
>     }
> 
> If @key is a recognized key name, return its (positive) code.
> Else, if @key is a hexadecimal number between 1 and 0xff, and a
> recognized key with that code exists, return the number.
> Else, return -1.
> 
> The regression is *not* that the hexadecimal format isn't recognized
> anymore, it's that numbers that don't have a key definition are now
> rejected.

Yes.

> > This commit fixes the problem by adding hex value support down
> > the QMP interface, qmp_send_key().
> >
> > In more detail, this commit:
> >
> >  1. Adds the KeyValue union. This can represent an hex value or
> >     a QKeyCode value
> >
> >  2. *Changes* the QMP send-key command to take an KeyValue argument
> >     instead of a QKeyCode one
> >
> >  3. Adapt hmp_send_key() to the QMP interface changes
> >
> > Item 2 is an incompatible change, but as we're in development phase
> > (and this command has been merged a few weeks ago) this shouldn't be
> > a problem.
> >
> > Finally, it's not possible to split this commit without breaking the
> > build.
> >
> > Reported-by: Avi Kivity <address@hidden>
> > Signed-off-by: Luiz Capitulino <address@hidden>
> > ---
> >  hmp.c            | 43 +++++++++++++++++++++++++++++--------------
> >  input.c          | 33 +++++++++++++++++++++++++++------
> >  qapi-schema.json | 20 +++++++++++++++++---
> >  3 files changed, 73 insertions(+), 23 deletions(-)
> >
> > diff --git a/hmp.c b/hmp.c
> > index ba6fbd3..8738dc5 100644
> > --- a/hmp.c
> > +++ b/hmp.c
> > @@ -1109,13 +1109,13 @@ void hmp_closefd(Monitor *mon, const QDict *qdict)
> >  void hmp_send_key(Monitor *mon, const QDict *qdict)
> >  {
> >      const char *keys = qdict_get_str(qdict, "keys");
> > -    QKeyCodeList *keylist, *head = NULL, *tmp = NULL;
> > +    KeyValueList *keylist, *head = NULL, *tmp = NULL;
> >      int has_hold_time = qdict_haskey(qdict, "hold-time");
> >      int hold_time = qdict_get_try_int(qdict, "hold-time", -1);
> >      Error *err = NULL;
> >      char keyname_buf[16];
> >      char *separator;
> > -    int keyname_len, idx;
> > +    int keyname_len;
> >  
> >      while (1) {
> >          separator = strchr(keys, '-');
> > @@ -1129,15 +1129,8 @@ void hmp_send_key(Monitor *mon, const QDict *qdict)
> >          }
> >          keyname_buf[keyname_len] = 0;
> >  
> > -        idx = index_from_key(keyname_buf);
> > -        if (idx == Q_KEY_CODE_MAX) {
> > -            monitor_printf(mon, "invalid parameter: %s\n", keyname_buf);
> > -            break;
> > -        }
> > -
> >          keylist = g_malloc0(sizeof(*keylist));
> > -        keylist->value = idx;
> > -        keylist->next = NULL;
> > +        keylist->value = g_malloc0(sizeof(*keylist->value));
> >  
> >          if (!head) {
> >              head = keylist;
> > @@ -1147,17 +1140,39 @@ void hmp_send_key(Monitor *mon, const QDict *qdict)
> >          }
> >          tmp = keylist;
> >  
> > +        if (strstart(keyname_buf, "0x", NULL)) {
> > +            char *endp;
> > +            int value = strtoul(keyname_buf, &endp, 0);
> > +            if (*endp != '\0') {
> > +                goto err_out;
> > +            }
> > +            keylist->value->kind = KEY_VALUE_KIND_NUMBER;
> > +            keylist->value->number = value;
> > +        } else {
> > +            int idx = index_from_key(keyname_buf);
> > +            if (idx == Q_KEY_CODE_MAX) {
> > +                goto err_out;
> > +            }
> > +            keylist->value->kind = KEY_VALUE_KIND_QCODE;
> > +            keylist->value->qcode = idx;
> > +        }
> > +
> 
> TL;DR: this differs unnecessarily from the pre-QAPI code, which makes
> the fix less obvious than it could be.  But I think it should work, and
> unbreaking autotest quickly is more important than making this patch
> perfect, so I'm *not* asking for a respin because of that.
> 
> Strings starting with "0x" are interpreted differently than before the
> QAPI conversion.
> 
> Before:
> 
>     If @key is a recognized key name, use its (positive) code.
>     Else, if @key is a hexadecimal number between 1 and 0xff, use the
>     number.
>     Else, error.
> 
> After:
> 
>     If @key starts with "0x"
>         If @key is a number, use it (range check is done later)
>         Else, error
>     Else
>         If it's a recognized key name, use its (positive) code
>         Else, error.
> 
> Makes a difference only if key names starting with "0x" exist.  None
> exist now, and such names aren't likely to appear in the future.
> 
> Aside: codes starting with a digit do exist, and that's why we can do
> only hexadecimal numeric keys.
> 
> The use of strtoul() here is sloppy, but it's no worse as before, in
> index_from_key():
> 
> * Numbers overflowing int are silently truncated, as before.
> 
> * Numbers outside 0x01..0xff (possibly after truncation) are still
>   flagged as error, in qmp_send_key() below.
> 
> >          if (!separator) {
> >              break;
> >          }
> >          keys = separator + 1;
> >      }
> >  
> > -    if (idx != Q_KEY_CODE_MAX) {
> > -        qmp_send_key(head, has_hold_time, hold_time, &err);
> > -    }
> > +    qmp_send_key(head, has_hold_time, hold_time, &err);
> >      hmp_handle_error(mon, &err);
> > -    qapi_free_QKeyCodeList(head);
> > +
> > +out:
> > +    qapi_free_KeyValueList(head);
> > +    return;
> > +
> > +err_out:
> > +    monitor_printf(mon, "invalid parameter: %s\n", keyname_buf);
> > +    goto out;
> 
> Jumping forward and backward like that is a bit ugly, but let's unbreak
> autotest.
> 
> >  }
> >  
> >  void hmp_screen_dump(Monitor *mon, const QDict *qdict)
> > diff --git a/input.c b/input.c
> > index 32c6057..76ade64 100644
> > --- a/input.c
> > +++ b/input.c
> > @@ -228,6 +228,23 @@ static int *keycodes;
> >  static int keycodes_size;
> >  static QEMUTimer *key_timer;
> >  
> > +static int keycode_from_keyvalue(const KeyValue *value)
> > +{
> > +    if (value->kind == KEY_VALUE_KIND_QCODE) {
> > +        return key_defs[value->qcode];
> > +    } else {
> > +        assert(value->kind == KEY_VALUE_KIND_NUMBER);
> > +        return value->number;
> > +    }
> > +}
> > +
> > +static void free_keycodes(void)
> > +{
> > +    g_free(keycodes);
> > +    keycodes = NULL;
> > +    keycodes_size = 0;
> > +}
> > +
> >  static void release_keys(void *opaque)
> >  {
> >      int i;
> > @@ -239,16 +256,14 @@ static void release_keys(void *opaque)
> >          kbd_put_keycode(keycodes[i]| 0x80);
> >      }
> >  
> > -    g_free(keycodes);
> > -    keycodes = NULL;
> > -    keycodes_size = 0;
> > +    free_keycodes();
> >  }
> >  
> > -void qmp_send_key(QKeyCodeList *keys, bool has_hold_time, int64_t 
> > hold_time,
> > +void qmp_send_key(KeyValueList *keys, bool has_hold_time, int64_t 
> > hold_time,
> >                    Error **errp)
> >  {
> >      int keycode;
> > -    QKeyCodeList *p;
> > +    KeyValueList *p;
> >  
> >      if (!key_timer) {
> >          key_timer = qemu_new_timer_ns(vm_clock, release_keys, NULL);
> > @@ -265,7 +280,13 @@ void qmp_send_key(QKeyCodeList *keys, bool 
> > has_hold_time, int64_t hold_time,
> >  
> >      for (p = keys; p != NULL; p = p->next) {
> >          /* key down events */
> > -        keycode = key_defs[p->value];
> > +        keycode = keycode_from_keyvalue(p->value);
> > +        if (keycode < 0x01 || keycode > 0xff) {
> > +            error_setg(errp, "invalid hex keycode 0x%x\n", keycode);
> > +            free_keycodes();
> > +            return;
> > +        }
> > +
> >          if (keycode & 0x80) {
> >              kbd_put_keycode(0xe0);
> >          }
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 14e4419..02135cc 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -2588,12 +2588,26 @@
> >               'lf', 'help', 'meta_l', 'meta_r', 'compose' ] }
> >  
> >  ##
> > +# @KeyValue
> > +#
> > +# Represents a keyboard key.
> > +# 
> 
> Trailing whitespace, could be fixed up on merge if we care.

Fixed in my queue.

> 
> > +# Since: 1.3.0
> > +##
> > +{ 'union': 'KeyValue',
> > +  'data': {
> > +    'number': 'int',
> > +    'qcode': 'QKeyCode' } }
> > +
> > +##
> >  # @send-key:
> >  #
> >  # Send keys to guest.
> >  #
> > -# @keys: key sequence. 'keys' is the name of the key. Use a JSON array to
> > -#        press several keys simultaneously.
> > +# @keys: An array of @KeyValue elements. All @KeyValues in this array are
> > +#        simultaneously sent to the guest. A @KeyValue.number value is sent
> > +#        directly to the guest, while @KeyValue.qcode must be a valid
> > +#        @QKeyCode value
> >  #
> >  # @hold-time: #optional time to delay key up events, milliseconds. Defaults
> >  #             to 100
> > @@ -2605,7 +2619,7 @@
> >  #
> >  ##
> >  { 'command': 'send-key',
> > -  'data': { 'keys': ['QKeyCode'], '*hold-time': 'int' } }
> > +  'data': { 'keys': ['KeyValue'], '*hold-time': 'int' } }
> >  
> >  ##
> >  # @screendump:
>