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, 3 insertions, 2 deletions

diff --git a/tools/libxl/libxlu_disk_l.l b/tools/libxl/libxlu_disk_l.l
index a3e71808fa..6e53928664 100644
--- a/tools/libxl/libxlu_disk_l.l
+++ b/tools/libxl/libxlu_disk_l.l
@@ -92,11 +92,12 @@ static void setaccess(DiskParseContext *dpc, const char *str) {
 
 /* Sets ->format from the string.  IDL should provide something for this. */
 static void setformat(DiskParseContext *dpc, const char *str) {
-    if (!strcmp(str,"") ||
-             !strcmp(str,"raw"))    DSET(dpc,format,FORMAT,str,RAW);
+    if      (!strcmp(str,""))       DSET(dpc,format,FORMAT,str,RAW);
+    else if (!strcmp(str,"raw"))    DSET(dpc,format,FORMAT,str,RAW);
     else if (!strcmp(str,"qcow"))   DSET(dpc,format,FORMAT,str,QCOW);
     else if (!strcmp(str,"qcow2"))  DSET(dpc,format,FORMAT,str,QCOW2);
     else if (!strcmp(str,"vhd"))    DSET(dpc,format,FORMAT,str,VHD);
+    else if (!strcmp(str,"empty"))  DSET(dpc,format,FORMAT,str,EMPTY);
     else xlu__disk_err(dpc,str,"unknown value for format");
 }