[Libvir] [PATCH] Fix strange error message in virsh attach-device

[Daniel Veillard]

On Fri, May 25, 2007 at 07:42:12PM +0900, Masayuki Sunou wrote:
> Hi
> 
> Now, virsh attach-device displays the following messages when "device"
> attribute of "disk" element is "floppy" in XML.
> 
> # virsh attach-device HVM_RH4_file floppy.xml
> libvir: Xen Daemon error : POST operation failed: (xend.err 'Invalid Configuration: XendConfig: @\x14\xce not a valid device type')
> error: Failed to attach device from floppy.xml

  can you provide floppy.xml content too to test the problem ?

> This patch fixes this strange error message displaying "@\x14\xce".

  okay, buffer problem.

> Description of this patch 
>   VirDomainParseXMLDiskDesc() returns 0 without putting data in virBuffer,
>   when "floppy" is set.
>   Therefore, virParseXMLDevice() returns no initialized data, and
>   xenDaemonAttachDevice() passes Xen this data. 
>   Because virDomainParseXMLDesc() works wrong when this patch changes
>   return value of VirDomainParseXMLDiskDesc(),this patch fixes
>   virParseXMLDevice() as follows.
>     - Initialize data
>     - Return error if data does not change.
>   As a result, xenDaemonAttachDevice() doesn't pass strange data to Xen,
>   and Xen doesn't return strange error message.
> 
> 
> Signed-off-by: Masayuki Sunou <fj1826dm at aa.jp.fujitsu.com>
> 
> Thanks,
> Masayuki Sunou.
> 
> ----------------------------------------------------------------------
> Index: src/xml.c
> ===================================================================
> RCS file: /data/cvs/libvirt/src/xml.c,v
> retrieving revision 1.73
> diff -u -p -r1.73 xml.c
> --- src/xml.c   23 Apr 2007 07:41:23 -0000      1.73
> +++ src/xml.c   25 May 2007 09:46:56 -0000
> @@ -1481,6 +1481,7 @@ virParseXMLDevice(virConnectPtr conn, ch
>          return (NULL);
>      buf.size = 1000;
>      buf.use = 0;
> +    memset(buf.content, 0, (size_t)buf.size);

 buf.use = 0 means we are using 0 bytes of the buffer. That's the semantic
of buffer usage, if you really want to make it zero terminated, just use
       buf.content[0] = 0;

>      xml = xmlReadDoc((const xmlChar *) xmldesc, "domain.xml", NULL,
>                       XML_PARSE_NOENT | XML_PARSE_NONET |
>                       XML_PARSE_NOERROR | XML_PARSE_NOWARNING);
> @@ -1492,6 +1493,9 @@ virParseXMLDevice(virConnectPtr conn, ch
>      if (xmlStrEqual(node->name, BAD_CAST "disk")) {
>          if (virDomainParseXMLDiskDesc(conn, node, &buf, hvm, xendConfigVersion) != 0)
>              goto error;
> +         /* SXP is not created when device is "floppy". */
> +        else if (!strlen(buf.content))
> +            goto error;

  use buf->use instead of strlen(buf.content)

If you provide the XML to reproduce it I could double-check this, 

  thanks,

Daniel

-- 
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Daniel Veillard      | virtualization library  http://libvirt.org/
veillard at redhat.com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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