[PATCH 2/3] tools/libxl: Simplfy the out path in libxl__domain_get_device_model_uid()

[Andrew Cooper <andrew.cooper3@citrix.com>]

All paths heading towards `out` have rc = 0.  Assert this property.

The intended_uid check is an error path.  Use the err label rather than
falling into subsequent success logic.

With the above two changes, the two `if (!rc)` checks can be dropped.

Now, both remaining tests start with `if (user ...)`.  Combine the two blocks.

No functional change, but far simpler logic to follow.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Ian Jackson <iwj@xenproject.org>
CC: Wei Liu <wl@xen.org>
CC: Anthony PERARD <anthony.perard@citrix.com>
---
 tools/libs/light/libxl_dm.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c
index 30b3242e57..7843c283ca 100644
--- a/tools/libs/light/libxl_dm.c
+++ b/tools/libs/light/libxl_dm.c
@@ -243,16 +243,17 @@ static int libxl__domain_get_device_model_uid(libxl__gc *gc,
     goto err;
 
 out:
-    /* First, do a root check if appropriate */
-    if (!rc) {
-        if (user && intended_uid == 0) {
+    assert(rc == 0);
+
+    if (user) {
+        /* First, do a root check if appropriate */
+        if (intended_uid == 0) {
             LOGD(ERROR, guest_domid, "intended_uid is 0 (root)!");
             rc = ERROR_INVAL;
+            goto err;
         }
-    }
 
-    /* Then do the final set, if still appropriate */
-    if (!rc && user) {
+        /* Then do the final set. */
         state->dm_runas = user;
         if (kill_by_uid)
             state->dm_kill_uid = GCSPRINTF("%ld", (long)intended_uid);
-- 
2.11.0