rpc: Maintain separate xlator pointer in 'rpcsvc_state'

The structure 'rpcsvc_state', which maintains rpc server
state had no separate pointer to track the translator.
It was using the mydata pointer itself. So callers were
forced to send xlator pointer as mydata which is opaque
(void pointer) by function prototype.

'rpcsvc_register_init' is setting svc->mydata with xlator
pointer. 'rpcsvc_register_notify' is overwriting svc->mydata
with mydata pointer. And rpc interprets svc->mydata as
xlator pointer internally. If someone passes non xlator
structure pointer to rpcsvc_register_notify as libgfchangelog
currently does, it might corrupt mydata. So interpreting opaque
mydata as xlator pointer is incorrect as it is caller's choice
to send mydata as any type of data to 'rpcsvc_register_notify'.

Maintaining two different pointers in 'rpcsvc_state' for xlator
and mydata solves the issue.

BUG: 1218381
Change-Id: I4c28937a30845e3f41b6fc7a09036149c816659b
Signed-off-by: Kotresh HR <khiremat@redhat.com>
Reviewed-on: http://review.gluster.org/10366
Reviewed-on: http://review.gluster.org/10534
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Tested-by: NetBSD Build System
Reviewed-by: Aravinda VK <avishwan@redhat.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

2 files changed, 7 insertions, 5 deletions

diff --git a/rpc/rpc-lib/src/rpcsvc-common.h b/rpc/rpc-lib/src/rpcsvc-common.h
index 832645bd12a..dd958032336 100644
--- a/rpc/rpc-lib/src/rpcsvc-common.h
+++ b/rpc/rpc-lib/src/rpcsvc-common.h
@@ -16,6 +16,7 @@
 #include "compat.h"
 #include "glusterfs.h"
 #include "dict.h"
+#include "xlator.h"
 
 typedef enum {
         RPCSVC_EVENT_ACCEPT,
@@ -69,7 +70,8 @@ typedef struct rpcsvc_state {
         struct list_head        notify;
         int                     notify_count;
 
-        void                    *mydata; /* This is xlator */
+        xlator_t                *xl;      /* xlator */
+        void                    *mydata;
         rpcsvc_notify_t         notifyfn;
         struct mem_pool         *rxpool;
         rpcsvc_drc_globals_t    *drc;
diff --git a/rpc/rpc-lib/src/rpcsvc.c b/rpc/rpc-lib/src/rpcsvc.c
index b395149e032..be95d25b1b1 100644
--- a/rpc/rpc-lib/src/rpcsvc.c
+++ b/rpc/rpc-lib/src/rpcsvc.c
@@ -677,7 +677,7 @@ rpcsvc_handle_rpc_call (rpcsvc_t *svc, rpc_transport_t *trans,
 
         if (req->rpc_err == SUCCESS) {
                 /* Before going to xlator code, set the THIS properly */
-                THIS = svc->mydata;
+                THIS = svc->xl;
 
                 actor_fn = actor->actor;
 
@@ -1802,7 +1802,7 @@ rpcsvc_register_notify (rpcsvc_t *svc, rpcsvc_notify_t notify, void *mydata)
         if (!wrapper) {
                 goto out;
         }
-        svc->mydata   = mydata;  /* this_xlator */
+        svc->mydata   = mydata;
         wrapper->data = mydata;
         wrapper->notify = notify;
 
@@ -2045,7 +2045,7 @@ rpcsvc_reconfigure_options (rpcsvc_t *svc, dict_t *options)
                 return (-1);
 
         /* Fetch the xlator from svc */
-        xlator = (xlator_t *) svc->mydata;
+        xlator = svc->xl;
         if (!xlator)
                 return (-1);
 
@@ -2311,7 +2311,7 @@ rpcsvc_init (xlator_t *xl, glusterfs_ctx_t *ctx, dict_t *options,
         ret = -1;
         svc->options = options;
         svc->ctx = ctx;
-        svc->mydata = xl;
+        svc->xl = xl;
         gf_log (GF_RPCSVC, GF_LOG_DEBUG, "RPC service inited.");
 
         gluster_dump_prog.options = options;