rpc-transport/socket: fix the state machine for XDATA reading

The socket state machine was broken for reading XDATA on the server.
This code was structured such that when there was a partial read in
a particular state, some variables would remain uninitialized in the
next 'run' of the state machine. Also did some re-org of the state
machine with two more states to make the code more readable and similar
in state-breakup pattern to the other states.

Change-Id: Ia32c78d4b9567bb08c6df8dc9fd6f05749d312a4
BUG: 829062
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.com/3524
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

2 files changed, 40 insertions, 11 deletions

diff --git a/rpc/rpc-transport/socket/src/socket.c b/rpc/rpc-transport/socket/src/socket.c
index cf30e7d7d..0fee6cb41 100644
--- a/rpc/rpc-transport/socket/src/socket.c
+++ b/rpc/rpc-transport/socket/src/socket.c
@@ -815,7 +815,6 @@ __socket_read_vectored_request (rpc_transport_t *this, rpcsvc_vector_sizer vecto
         uint32_t          remaining_size         = 0;
         ssize_t           readsize               = 0;
         size_t            size = 0;
-        char             *proghdr_buf = NULL;
 
         GF_VALIDATE_OR_GOTO ("socket", this, out);
         GF_VALIDATE_OR_GOTO ("socket", this->private, out);
@@ -872,10 +871,13 @@ __socket_read_vectored_request (rpc_transport_t *this, rpcsvc_vector_sizer vecto
 
         case SP_STATE_READ_VERFBYTES:
 sp_state_read_verfbytes:
-                proghdr_buf = priv->incoming.frag.fragcurrent;
+		/* set the base_addr 'persistently' across multiple calls
+		   into the state machine */
+                priv->incoming.proghdr_base_addr = priv->incoming.frag.fragcurrent;
+
                 priv->incoming.frag.call_body.request.vector_sizer_state =
                         vector_sizer (priv->incoming.frag.call_body.request.vector_sizer_state,
-                                      &readsize, proghdr_buf,
+                                      &readsize, priv->incoming.proghdr_base_addr,
                                       priv->incoming.frag.fragcurrent);
                 __socket_proto_init_pending (priv, readsize);
                 priv->incoming.frag.call_body.request.vector_state
@@ -885,21 +887,41 @@ sp_state_read_verfbytes:
 
         case SP_STATE_READING_PROGHDR:
                 __socket_proto_read (priv, ret);
-sp_state_reading_proghdr:
+		priv->incoming.frag.call_body.request.vector_state =
+			SP_STATE_READ_PROGHDR;
+
+		/* fall through */
+
+	case SP_STATE_READ_PROGHDR:
+sp_state_read_proghdr:
                 priv->incoming.frag.call_body.request.vector_sizer_state =
                         vector_sizer (priv->incoming.frag.call_body.request.vector_sizer_state,
-                                      &readsize, proghdr_buf,
+                                      &readsize,
+				      priv->incoming.proghdr_base_addr,
                                       priv->incoming.frag.fragcurrent);
                 if (readsize == 0) {
                         priv->incoming.frag.call_body.request.vector_state =
-                                SP_STATE_READ_PROGHDR;
-                } else {
-                        __socket_proto_init_pending (priv, readsize);
-                        __socket_proto_read (priv, ret);
-                        goto sp_state_reading_proghdr;
+                                SP_STATE_READ_PROGHDR_XDATA;
+			goto sp_state_read_proghdr_xdata;
                 }
 
-        case SP_STATE_READ_PROGHDR:
+		__socket_proto_init_pending (priv, readsize);
+
+                priv->incoming.frag.call_body.request.vector_state =
+			SP_STATE_READING_PROGHDR_XDATA;
+
+		/* fall through */
+
+	case SP_STATE_READING_PROGHDR_XDATA:
+		__socket_proto_read (priv, ret);
+
+		priv->incoming.frag.call_body.request.vector_state =
+			SP_STATE_READ_PROGHDR;
+		/* check if the vector_sizer() has more to say */
+		goto sp_state_read_proghdr;
+
+        case SP_STATE_READ_PROGHDR_XDATA:
+sp_state_read_proghdr_xdata:
                 if (priv->incoming.payload_vector.iov_base == NULL) {
 
                         size = RPC_FRAGSIZE (priv->incoming.fraghdr) -
diff --git a/rpc/rpc-transport/socket/src/socket.h b/rpc/rpc-transport/socket/src/socket.h
index 6d6802a54..0304f1db1 100644
--- a/rpc/rpc-transport/socket/src/socket.h
+++ b/rpc/rpc-transport/socket/src/socket.h
@@ -72,6 +72,12 @@ typedef enum {
         SP_STATE_READ_VERFBYTES,        /* read verifier data */
         SP_STATE_READING_PROGHDR,
         SP_STATE_READ_PROGHDR,
+        SP_STATE_READING_PROGHDR_XDATA,
+        SP_STATE_READ_PROGHDR_XDATA,    /* It's a bad "name" in the generic
+					   RPC state machine, but greatly
+					   aids code review (and xdata is
+					   the only "consumer" of this state)
+					*/
         SP_STATE_READING_PROG,
 } sp_rpcfrag_vectored_request_state_t;
 
@@ -165,6 +171,7 @@ typedef struct {
                         sp_rpcfrag_simple_msg_state_t     simple_state;
                         sp_rpcfrag_state_t state;
                 } frag;
+		char                *proghdr_base_addr;
                 struct iobuf        *iobuf;
                 size_t               iobuf_size;
                 struct iovec         vector[2];