[Spice-devel] [PATCH] [vd_agent] close the file handler if file_size = 0

[Cody Chan]

After dragging a zero-size file, then I open it in guest,
I get a warning message box which says:
 "the process cannot access the file because it is being used by another
process".
And I get to know the file is occupied by vdagent. Now we look back the
process:

a) When dragging a zero-size file, spice-gtk gets the name and size, then
sends
the message to vd_agent with VD_AGENT_FILE_XFER_START
b) vd_agent receives and parsers the message, then gets file name and size,
creates(open)
the file and gets the handler, at last, sends
VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA
c) spice-gtk receives the VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA message,
the sends data with VD_AGENT_FILE_XFER_DATA
d) vd_agent receives and writes data to the file opened
e) After finishing the writing, vd_agent closes the handler

But in step c, we take a look the code:
//spice-channel.c
>static void file_xfer_read_cb(...)
>{
>    //...
>    count = g_input_stream_read_finish(G_INPUT_STREAM(task->file_stream),
res, &error);
>    if (count > 0) {
>        task->read_bytes += count;
>        file_xfer_queue(task, count);
>        file_xfer_flush_async(channel, task->cancellable,
>                              file_xfer_data_flushed_cb, task);
>        task->pending = TRUE;
>    } else if (error) {
>        VDAgentFileXferStatusMessage msg = {
>            .id = task->id,
>            .result = VD_AGENT_FILE_XFER_STATUS_ERROR,
>        };
>        agent_msg_queue_many(task->channel, VD_AGENT_FILE_XFER_STATUS,
>                             &msg, sizeof(msg), NULL);
>        spice_channel_wakeup(SPICE_CHANNEL(task->channel), FALSE);
>        file_xfer_completed(task, error);
>    }
>}

If count == 0, then it does nothing!
Then vd_agent will receive nothing after opening a file, and always occupy
the file.
Here we close the file if file_size = 0, even though it doesn't make sense
to send
a zero-size file.

​
---
 vdagent/file_xfer.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/vdagent/file_xfer.cpp b/vdagent/file_xfer.cpp
index 34a9ee6..17d842e 100644
--- a/vdagent/file_xfer.cpp
+++ b/vdagent/file_xfer.cpp
@@ -89,6 +89,10 @@ void FileXfer::handle_start(VDAgentFileXferStartMessage*
start,
         vd_printf("failed creating %s %lu", file_path, GetLastError());
         return;
     }
+    if (file_size == 0){
+        CloseHandle(handle);
+        return;
+    }
     task = new FileXferTask(handle, file_size, file_path);
     _tasks[start->id] = task;
     status->result = VD_AGENT_FILE_XFER_STATUS_CAN_SEND_DATA;
--
1.9.3

-- 
QSBDT0RFUiBGUk9NIFJJRVNUIE9GIENUU0VV
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