Re: [Qemu-devel] [PATCH 4/5] qemu-ga: win32: isolate virtio-serial specific code

[Michael Roth <mdroth@linux.vnet.ibm.com>]

On Thu, Nov 01, 2012 at 02:33:29PM -0200, Luiz Capitulino wrote:
> On Thu, 1 Nov 2012 11:22:13 -0500
> Michael Roth <mdroth@linux.vnet.ibm.com> wrote:
> 
> > On Wed, Oct 31, 2012 at 03:45:19PM -0200, Luiz Capitulino wrote:
> > > This commit prepares ga_channel_new(), ga_channel_read() and
> > > ga_channel_open() for isa-serial support.
> > > 
> > > Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> > 
> > Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> > 
> > Though I'm wondering if it'd be nicer to:
> > 
> >  1) Add a GAChannelOps struct with pointers for init/read/write/write_all
> >  2) Move all the method-specific init stuff from ga_channel_new() into
> >     method-specific init functions (which all use ga_channel_open() as
> >     a general helper function, or maybe roll the CreateFile() into the 
> >     init routines with the proper flags hard-coded
> >  3) Have ga_channel_new() simply hang the proper GAChannelOps* off of
> >     the GAChannel it create and then call GAChannel->ops->init(self)
> >  4) Make ga_channel_read/write/write_all(self) wrappers around
> >     GAChannel->ops->read/write/write_all(self)
> 
> Can this be a future improvement? I was also wondering if it would be good
> to have GAOps instead of having global functions for win32 & posix.

Sure, I wouldn't hold up the series for it. I agree it seems like a good
future improvement.

> 
> > 
> > > ---
> > >  qga/channel-win32.c | 75 ++++++++++++++++++++++++++++++-----------------------
> > >  1 file changed, 42 insertions(+), 33 deletions(-)
> > > 
> > > diff --git a/qga/channel-win32.c b/qga/channel-win32.c
> > > index 8e259c3..c173270 100644
> > > --- a/qga/channel-win32.c
> > > +++ b/qga/channel-win32.c
> > > @@ -213,14 +213,20 @@ GIOStatus ga_channel_read(GAChannel *c, char *buf, size_t size, gsize *count)
> > >          return G_IO_STATUS_ERROR;
> > >      }
> > > 
> > > -    *count = to_read = MIN(size, rs->pending);
> > > -    if (to_read) {
> > > -        memcpy(buf, rs->buf + rs->cur, to_read);
> > > -        rs->cur += to_read;
> > > -        rs->pending -= to_read;
> > > -        status = G_IO_STATUS_NORMAL;
> > > -    } else {
> > > -        status = G_IO_STATUS_AGAIN;
> > > +    switch (c->method) {
> > > +    case GA_CHANNEL_VIRTIO_SERIAL:
> > > +        *count = to_read = MIN(size, rs->pending);
> > > +        if (to_read) {
> > > +            memcpy(buf, rs->buf + rs->cur, to_read);
> > > +            rs->cur += to_read;
> > > +            rs->pending -= to_read;
> > > +            status = G_IO_STATUS_NORMAL;
> > > +        } else {
> > > +            status = G_IO_STATUS_AGAIN;
> > > +        }
> > > +        break;
> > > +    default:
> > > +        abort(); /* impossible */
> > >      }
> > > 
> > >      return status;
> > > @@ -285,23 +291,11 @@ GIOStatus ga_channel_write_all(GAChannel *c, const char *buf, size_t size)
> > >      return status;
> > >  }
> > > 
> > > -static gboolean ga_channel_open(GAChannel *c, GAChannelMethod method,
> > > -                                const gchar *path)
> > > +static gboolean ga_channel_open(GAChannel *c, const gchar *path, int flags)
> > >  {
> > > -    if (!method == GA_CHANNEL_VIRTIO_SERIAL) {
> > > -        g_critical("unsupported communication method");
> > > -        return false;
> > > -    }
> > > -
> > >      c->handle = CreateFile(path, GENERIC_READ | GENERIC_WRITE, 0, NULL,
> > > -                           OPEN_EXISTING,
> > > -                           FILE_FLAG_NO_BUFFERING | FILE_FLAG_OVERLAPPED, NULL);
> > > -    if (c->handle == INVALID_HANDLE_VALUE) {
> > > -        g_critical("error opening path");
> > > -        return false;
> > > -    }
> > > -
> > > -    return true;
> > > +                           OPEN_EXISTING, FILE_FLAG_NO_BUFFERING | flags, NULL);
> > > +    return (c->handle == INVALID_HANDLE_VALUE) ? false : true;
> > >  }
> > > 
> > >  GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
> > > @@ -310,27 +304,42 @@ GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path,
> > >      GAChannel *c = g_malloc0(sizeof(GAChannel));
> > >      SECURITY_ATTRIBUTES sec_attrs;
> > > 
> > > -    if (!ga_channel_open(c, method, path)) {
> > > -        g_critical("error opening channel");
> > > -        g_free(c);
> > > -        return NULL;
> > > +    switch (method) {
> > > +    case GA_CHANNEL_VIRTIO_SERIAL:
> > > +        if (!ga_channel_open(c, path, FILE_FLAG_OVERLAPPED)) {
> > > +            g_critical("error opening channel (path: %s)", path);
> > > +            goto out_err;
> > > +        }
> > > +
> > > +        sec_attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
> > > +        sec_attrs.lpSecurityDescriptor = NULL;
> > > +        sec_attrs.bInheritHandle = false;
> > > +        c->rstate.ov.hEvent = CreateEvent(&sec_attrs, FALSE, FALSE, NULL);
> > > +        if (!c->rstate.ov.hEvent) {
> > > +            g_critical("can't create event");
> > > +            goto out_err;
> > > +        }
> > > +
> > > +        c->source = ga_channel_create_watch_ov(c);
> > > +        break;
> > > +    default:
> > > +        g_critical("unsupported communication method");
> > > +        goto out_err;
> > >      }
> > > 
> > >      c->cb = cb;
> > >      c->user_data = opaque;
> > >      c->method = method;
> > > 
> > > -    sec_attrs.nLength = sizeof(SECURITY_ATTRIBUTES);
> > > -    sec_attrs.lpSecurityDescriptor = NULL;
> > > -    sec_attrs.bInheritHandle = false;
> > > -
> > >      c->rstate.buf_size = QGA_READ_COUNT_DEFAULT;
> > >      c->rstate.buf = g_malloc(QGA_READ_COUNT_DEFAULT);
> > > -    c->rstate.ov.hEvent = CreateEvent(&sec_attrs, FALSE, FALSE, NULL);
> > > 
> > > -    c->source = ga_channel_create_watch_ov(c);
> > >      g_source_attach(c->source, NULL);
> > >      return c;
> > > +
> > > +out_err:
> > > +    g_free(c);
> > > +    return NULL;
> > >  }
> > > 
> > >  void ga_channel_free(GAChannel *c)
> > > -- 
> > > 1.7.12.315.g682ce8b
> > > 
> > 
>