xl: support empty CDROM devices

The important change here is to xlu_disk_parse to correctly set format == EMPTY
for CDROM devices which are empty. Test cases are added which check for
correctness here.

xend accepts ',hdc:cdrom,r'[0] as an empty CDROM drive however this is not
consistent with the xl syntax in docs/misc/xl-disk-configuration.txt which
requires ',,hdc:cdrom,r' (the additional positional paramter is the format).
I'm not sure if/how this can be fixed. Note that xend does not accept
',,hdc:cdrom,r'

There are several incidental cleanups included the the cdrom-{insert,eject}
commands:
  - add a dry-run mode
  - use the non-deprecated disk specification syntax
  - check for and report errors from libxl_cdrom_insert

[0] http://wiki.xen.org/wiki/CD_Rom_Support_in_Xen

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>

1 files changed, 21 insertions, 9 deletions

diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
index cbd760874e..25ce77737f 100644
--- a/docs/man/xl.pod.1
+++ b/docs/man/xl.pod.1
@@ -1037,9 +1037,12 @@ in the domain.
 
 List virtual block devices for a domain.
 
-=item B<cd-insert> I<domain-id> I<VirtualDevice> I<be-dev>
+=item B<cd-insert> I<domain-id> I<VirtualDevice> I<target>
 
-Insert a cdrom into a guest domain's cd drive. Only works with HVM domains.
+Insert a cdrom into a guest domain's existing virtial cd drive. The
+virtual drive must already exist but can be current empty.
+
+Only works with HVM domains.
 
 B<OPTIONS>
 
@@ -1047,20 +1050,29 @@ B<OPTIONS>
 
 =item I<VirtualDevice>
 
-How the device should be presented to the guest domain; for example /dev/hdc.
+How the device should be presented to the guest domain; for example "hdc".
 
-=item I<be-dev>
+=item I<target>
 
-the device in the backend domain (usually domain 0) to be exported; it
-can be a path to a file (file://path/to/file.iso). See B<disk> in
-L<xl.cfg(5)> for the details.
+the target path in the backend domain (usually domain 0) to be
+exported; Can be a block device or a file etc. See B<target> in
+F<docs/misc/xl-disk-configuration.txt>.
 
 =back
 
 =item B<cd-eject> I<domain-id> I<VirtualDevice>
 
-Eject a cdrom from a guest's cd drive. Only works with HVM domains.
-I<VirtualDevice> is the cdrom device in the guest to eject.
+Eject a cdrom from a guest's virtual cd drive. Only works with HVM domains.
+
+B<OPTIONS>
+
+=over 4
+
+=item I<VirtualDevice>
+
+How the device should be presented to the guest domain; for example "hdc".
+
+=back
 
 =back