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, 2 insertions, 0 deletions

diff --git a/tools/libxl/libxlu_disk.c b/tools/libxl/libxlu_disk.c
index 3d51defe1e..18fe386dbe 100644
--- a/tools/libxl/libxlu_disk.c
+++ b/tools/libxl/libxlu_disk.c
@@ -76,6 +76,8 @@ int xlu_disk_parse(XLU_Config *cfg,
     if (disk->is_cdrom) {
         disk->removable = 1;
         disk->readwrite = 0;
+        if (!disk->pdev_path || !strcmp(disk->pdev_path, ""))
+            disk->format = LIBXL_DISK_FORMAT_EMPTY;
     }
 
     if (!disk->vdev) {