mini-os: make frontends and xenbus optional

This adds compile-time logic to disable certain frontends in mini-os:
 - pcifront is disabled by default, enabled for ioemu
 - blkfront, netfront, fbfront, kbdfront, consfront are enabled by default
 - xenbus is required for any frontend, and is enabled by default

If all frontends and xenbus are disabled, mini-os will run without
needing to communicate with xenstore, making it suitable to run the
xenstore daemon. The console frontend is not required for the initial
console, only consoles opened via openpt or ptmx.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/extras/mini-os/include/lib.h b/extras/mini-os/include/lib.h
index 3d03cf40f8..1af2717c0b 100644
--- a/extras/mini-os/include/lib.h
+++ b/extras/mini-os/include/lib.h
@@ -184,11 +184,13 @@ extern struct file {
 	struct {
 	    struct consfront_dev *dev;
 	} cons;
+#ifdef CONFIG_XENBUS
         struct {
             /* To each xenbus FD is associated a queue of watch events for this
              * FD.  */
             xenbus_event_queue events;
         } xenbus;
+#endif
     };
     int read;	/* maybe available for read */
 } files[];