Modules: handle the busy module name

src/module.c

@@ -650,7 +650,7 @@ int RM_CreateCommand(RedisModuleCtx *ctx, const char *name, RedisModuleCmdFunc c
  *
  * This is an internal function, Redis modules developers don't need
  * to use it. */
-void RM_SetModuleAttribs(RedisModuleCtx *ctx, const char *name, int ver, int apiver){
+void RM_SetModuleAttribs(RedisModuleCtx *ctx, const char *name, int ver, int apiver) {
     RedisModule *module;
 
     if (ctx->module != NULL) return;
@@ -662,6 +662,19 @@ void RM_SetModuleAttribs(RedisModuleCtx *ctx, const char *name, int ver, int api
     ctx->module = module;
 }
 
+/* Return non-zero if the module name is busy.
+ * Otherwise zero is returned. */
+int RM_IsModuleNameBusy(const char *name) {
+    sds modulename = sdsnew(name);
+
+    /* Check if the module name is busy. */
+    if (dictFind(modules,modulename) != NULL) {
+        sdsfree(modulename);
+        return 1;
+    }
+    return 0;
+}
+
 /* Return the current UNIX time in milliseconds. */
 long long RM_Milliseconds(void) {
     return mstime();
@@ -3835,6 +3848,7 @@ void moduleRegisterCoreAPI(void) {
     REGISTER_API(Strdup);
     REGISTER_API(CreateCommand);
     REGISTER_API(SetModuleAttribs);
+    REGISTER_API(IsModuleNameBusy);
     REGISTER_API(WrongArity);
     REGISTER_API(ReplyWithLongLong);
     REGISTER_API(ReplyWithError);

src/redismodule.h

@@ -119,7 +119,8 @@ void *REDISMODULE_API_FUNC(RedisModule_Calloc)(size_t nmemb, size_t size);
 char *REDISMODULE_API_FUNC(RedisModule_Strdup)(const char *str);
 int REDISMODULE_API_FUNC(RedisModule_GetApi)(const char *, void *);
 int REDISMODULE_API_FUNC(RedisModule_CreateCommand)(RedisModuleCtx *ctx, const char *name, RedisModuleCmdFunc cmdfunc, const char *strflags, int firstkey, int lastkey, int keystep);
-int REDISMODULE_API_FUNC(RedisModule_SetModuleAttribs)(RedisModuleCtx *ctx, const char *name, int ver, int apiver);
+void REDISMODULE_API_FUNC(RedisModule_SetModuleAttribs)(RedisModuleCtx *ctx, const char *name, int ver, int apiver);
+int REDISMODULE_API_FUNC(RedisModule_IsModuleNameBusy)(const char *name);
 int REDISMODULE_API_FUNC(RedisModule_WrongArity)(RedisModuleCtx *ctx);
 int REDISMODULE_API_FUNC(RedisModule_ReplyWithLongLong)(RedisModuleCtx *ctx, long long ll);
 int REDISMODULE_API_FUNC(RedisModule_GetSelectedDb)(RedisModuleCtx *ctx);
@@ -238,6 +239,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(Strdup);
     REDISMODULE_GET_API(CreateCommand);
     REDISMODULE_GET_API(SetModuleAttribs);
+    REDISMODULE_GET_API(IsModuleNameBusy);
     REDISMODULE_GET_API(WrongArity);
     REDISMODULE_GET_API(ReplyWithLongLong);
     REDISMODULE_GET_API(ReplyWithError);
@@ -344,6 +346,7 @@ static int RedisModule_Init(RedisModuleCtx *ctx, const char *name, int ver, int
     REDISMODULE_GET_API(AbortBlock);
 #endif
 
+    if (RedisModule_IsModuleNameBusy(name)) return REDISMODULE_ERR;
     RedisModule_SetModuleAttribs(ctx,name,ver,apiver);
     return REDISMODULE_OK;
 }