xenstore: new XS_OPEN_SOCKETONLY flag; honour "-s" on tools' cmdline

The "-s" option to xenstore-ls is used by the xencommons startup
script to check whether xenstored is already running, before starting
it.

Since 22498:a40455ae9ad3, "-s" has been a no-op, and libxenstore will
always fall back to using xenbus.  The combined effect is that the
xencommons script deadlocks: xenstore-ls hangs waiting for xenstored,
which isn't started by xencommons because xencommons is waiting for
xenstore-ls.

In this patch, we:
 * Introduce a new XS_OPEN_SOCKETONLY flag which disables the
   fallback behaviour;
 * Make the xenstore command line tools use the new xs_open call
   rather than the old, deprecated xs_open_* calls (which are
   now identical).
 * Plumb the xenstore command line tools "-s" option to set the
   XS_OPEN_SOCKETONLY flag.
 * Change the type of the XS_OPEN_* flags so that they naturally have
   type unsigned long.

The "-s" option to xenstore-ls et al, and the XS_OPEN_SOCKETONLY flag,
are intended for use by toolstack infrastructure and should not
normally be used by higher-level code.

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

1 files changed, 2 insertions, 3 deletions

diff --git a/tools/xenstore/xenstore_client.c b/tools/xenstore/xenstore_client.c
index fe63b6b0c8..94b82b99af 100644
--- a/tools/xenstore/xenstore_client.c
+++ b/tools/xenstore/xenstore_client.c
@@ -633,9 +633,8 @@ main(int argc, char **argv)
 	    max_width = ws.ws_col - 2;
     }
 
-    xsh = socket ? xs_daemon_open() : xs_domain_open();
-    if (xsh == NULL)
-	err(1, socket ? "xs_daemon_open" : "xs_domain_open");
+    xsh = xs_open(socket ? XS_OPEN_SOCKETONLY : 0);
+    if (xsh == NULL) err(1, "xs_open");
 
 again:
     if (transaction) {