From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:60880) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTy2k-0000Mk-7L for qemu-devel@nongnu.org; Thu, 01 Nov 2012 12:54:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TTy2i-0008Re-T4 for qemu-devel@nongnu.org; Thu, 01 Nov 2012 12:54:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24214) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTy2i-0008RZ-Kh for qemu-devel@nongnu.org; Thu, 01 Nov 2012 12:54:56 -0400 Date: Thu, 1 Nov 2012 14:55:20 -0200 From: Luiz Capitulino Message-ID: <20121101145520.333245b7@doriath.home> In-Reply-To: <20121101163105.GK16157@illuin> References: <1351705520-24589-1-git-send-email-lcapitulino@redhat.com> <1351705520-24589-6-git-send-email-lcapitulino@redhat.com> <20121101163105.GK16157@illuin> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/5] qemu-ga: win32: add isa-serial support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Michael Roth Cc: qemu-devel@nongnu.org On Thu, 1 Nov 2012 11:31:05 -0500 Michael Roth wrote: > On Wed, Oct 31, 2012 at 03:45:20PM -0200, Luiz Capitulino wrote: > > It's implemented by opening the serial port in "non-blocking" mode > > and using the GSourceFuncs API in the following way: > > > > o prepare(): issue a read request. If something has been read, it's > > stored in rs->buf and rs->pending will store the number > > of bytes read. If there wasn't any bytes available, we > > set the timeout to 500 ms and return > > > > o check(): returns true if prepare() was able to read anything, > > otherwise return false > > > > o finalize(): does nothing > > > > At dispatch() time we simply copy the bytes read to the buffer passed > > to ga_channel_read(). > > > > Signed-off-by: Luiz Capitulino > > --- > > qga/channel-win32.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > > 1 file changed, 87 insertions(+) > > > > diff --git a/qga/channel-win32.c b/qga/channel-win32.c > > index c173270..887fe5f 100644 > > --- a/qga/channel-win32.c > > +++ b/qga/channel-win32.c > > @@ -179,6 +179,46 @@ static gboolean ga_channel_dispatch_ov(GSource *source, GSourceFunc unused, > > return success; > > } > > > > +static gboolean ga_channel_prepare(GSource *source, gint *timeout_ms) > > +{ > > + GAWatch *watch = (GAWatch *)source; > > + GAChannel *c = (GAChannel *)watch->channel; > > + GAChannelReadState *rs = &c->rstate; > > + DWORD count_read = 0; > > + bool success; > > + > > + success = ReadFile(c->handle, rs->buf, rs->buf_size, &count_read, NULL); > > + if (success) { > > + if (count_read == 0) { > > + *timeout_ms = 500; > > + return false; > > + } > > + rs->pending = count_read; > > + return true; > > + } > > + > > + return false; > > +} > > + > > +static gboolean ga_channel_check(GSource *source) > > +{ > > + GAWatch *watch = (GAWatch *)source; > > + GAChannel *c = (GAChannel *)watch->channel; > > + GAChannelReadState *rs = &c->rstate; > > + > > + return !!rs->pending; > > +} > > + > > +static gboolean ga_channel_dispatch(GSource *source, GSourceFunc unused, > > + gpointer user_data) > > +{ > > + GAWatch *watch = (GAWatch *)source; > > + GAChannel *c = (GAChannel *)watch->channel; > > + > > + g_assert(c->cb); > > + return c->cb(0, c->user_data); > > +} > > + > > static void ga_channel_finalize_ov(GSource *source) > > { > > g_debug("finalize"); > > @@ -203,6 +243,30 @@ static GSource *ga_channel_create_watch_ov(GAChannel *c) > > return source; > > } > > > > +static void ga_channel_finalize(GSource *source) > > +{ > > + g_debug("finalize"); > > +} > > + > > +GSourceFuncs ga_channel_watch_funcs = { > > + ga_channel_prepare, > > + ga_channel_check, > > + ga_channel_dispatch, > > + ga_channel_finalize > > +}; > > + > > +static GSource *ga_channel_create_watch(GAChannel *c) > > +{ > > + GSource *source = g_source_new(&ga_channel_watch_funcs, sizeof(GAWatch)); > > + GAWatch *watch = (GAWatch *)source; > > + > > + watch->channel = c; > > + watch->pollfd.fd = -1; > > + g_source_add_poll(source, &watch->pollfd); > > + > > + return source; > > +} > > + > > GIOStatus ga_channel_read(GAChannel *c, char *buf, size_t size, gsize *count) > > { > > GAChannelReadState *rs = &c->rstate; > > @@ -225,6 +289,12 @@ GIOStatus ga_channel_read(GAChannel *c, char *buf, size_t size, gsize *count) > > status = G_IO_STATUS_AGAIN; > > } > > break; > > + case GA_CHANNEL_ISA_SERIAL: > > + memcpy(buf, rs->buf, rs->pending); > > Do we really want to ignore size? Seems like we can overrun their buffer > if it's smaller than ours. You can use rs->start to track the number of > bytes theyve read so far and offset from that in prepare() size == rs->buf_size, so we're ok. Although this is sensible, as both buffers are not tied... I think that the intermediate buffer handling complicate things, and for isa-serial this is not needed. What about returning the buffer from ga_channel_read()? I mean, instead of: gchar buf[QGA_READ_COUNT_DEFAULT+1]; gsize count; ... ga_channel_read(s->channel, buf, QGA_READ_COUNT_DEFAULT, &count); We could have: gchar *buf; gsize count; ... ga_channel_read(s->channel, &buf, &count); > > > + *count = rs->pending; > > + rs->pending = 0; > > + status = G_IO_STATUS_NORMAL; > > + break; > > default: > > abort(); /* impossible */ > > } > > @@ -303,6 +373,7 @@ GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path, > > { > > GAChannel *c = g_malloc0(sizeof(GAChannel)); > > SECURITY_ATTRIBUTES sec_attrs; > > + COMMTIMEOUTS timeouts; > > > > switch (method) { > > case GA_CHANNEL_VIRTIO_SERIAL: > > @@ -322,6 +393,22 @@ GAChannel *ga_channel_new(GAChannelMethod method, const gchar *path, > > > > c->source = ga_channel_create_watch_ov(c); > > break; > > + case GA_CHANNEL_ISA_SERIAL: > > + if (!ga_channel_open(c, path, 0)) { > > + g_critical("error opening channel (path: %s)", path); > > + goto out_err; > > + } > > + > > + /* non-blocking I/O */ > > + memset(&timeouts, 0, sizeof(timeouts)); > > + timeouts.ReadIntervalTimeout = MAXDWORD; > > + if (!SetCommTimeouts(c->handle, &timeouts)) { > > + CloseHandle(c->handle); > > + goto out_err; > > + } > > + > > + c->source = ga_channel_create_watch(c); > > + break; > > default: > > g_critical("unsupported communication method"); > > goto out_err; > > -- > > 1.7.12.315.g682ce8b > > > > >