rpc: add spdk_rpc_verify_methods()

This returns true if all registered methods and aliases
are correct.  False means that an error like one of the
following occurred:

- duplicate method with same name
- alias specified for non-existant method
- alias specified for another alias

Also plumb this so that incorrect RPCs cause an SPDK
application to exit.

Note: there are cases where this would have been helpful
during the recent RPC renaming.

Fixes issue #940.

Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I235a433c9b8c01e82f16288a8d295e96c54e4eb1

Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/472441
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>

include/spdk/rpc.h

@@ -42,6 +42,18 @@
 extern "C" {
 #endif
 
+/**
+ * Verify correctness of registered RPC methods and aliases.
+ *
+ * Incorrect registrations include:
+ * - multiple RPC methods registered with the same name
+ * - RPC alias registered with a method that does not exist
+ * - RPC alias registered that points to another alias
+ *
+ * \return true if registrations are all correct, false otherwise
+ */
+bool spdk_rpc_verify_methods(void);
+
 /**
  * Start listening for RPC connections.
  *

lib/event/rpc.c

@@ -61,6 +61,11 @@ spdk_rpc_initialize(const char *listen_addr)
 		return;
 	}
 
+	if (!spdk_rpc_verify_methods()) {
+		spdk_app_stop(-EINVAL);
+		return;
+	}
+
 	/* Listen on the requested address */
 	rc = spdk_rpc_listen(listen_addr);
 	if (rc != 0) {

lib/rpc/rpc.c

@@ -51,6 +51,7 @@ static int g_rpc_lock_fd = -1;
 
 static struct spdk_jsonrpc_server *g_jsonrpc_server = NULL;
 static uint32_t g_rpc_state;
+static bool g_rpcs_correct = true;
 
 struct spdk_rpc_method {
 	const char *name;
@@ -249,7 +250,8 @@ spdk_rpc_register_method(const char *method, spdk_rpc_method_handler func, uint3
 
 	m = _get_rpc_method_raw(method);
 	if (m != NULL) {
-		SPDK_ERRLOG("duplicate RPC %s registered - ignoring...\n", method);
+		SPDK_ERRLOG("duplicate RPC %s registered...\n", method);
+		g_rpcs_correct = false;
 		return;
 	}
 
@@ -275,11 +277,13 @@ spdk_rpc_register_alias_deprecated(const char *method, const char *alias)
 	if (base == NULL) {
 		SPDK_ERRLOG("cannot create alias %s - method %s does not exist\n",
 			    alias, method);
+		g_rpcs_correct = false;
 		return;
 	}
 
 	if (base->is_alias_of != NULL) {
 		SPDK_ERRLOG("cannot create alias %s of alias %s\n", alias, method);
+		g_rpcs_correct = false;
 		return;
 	}
 
@@ -297,6 +301,12 @@ spdk_rpc_register_alias_deprecated(const char *method, const char *alias)
 	SLIST_INSERT_HEAD(&g_rpc_methods, m, slist);
 }
 
+bool
+spdk_rpc_verify_methods(void)
+{
+	return g_rpcs_correct;
+}
+
 int
 spdk_rpc_is_method_allowed(const char *method, uint32_t state_mask)
 {