loading of modules in child process

- config file(s) are scanned for "loadmodule" directives
  to have modules loaded again in child process, so they can
  properly serialize their data

Fixes #130

src/Win32_Interop/Win32_QFork_impl.c

@@ -23,12 +23,55 @@
 #include "..\server.h"
 #include "Win32_Portability.h"
 
+/*
+* Config file parameter filter that allows only "loadmodule" directives.
+*/
+int ConfigFilterModulesOnly(sds configLine) {
+    return strcasecmp(configLine, "loadmodule") == 0 ? TRUE : FALSE;
+}
+
+/*
+* Call to "SetupRedisGlobals" copies over "server" structure from the main process, but here
+* we are initializing parts of the application to allow modules to be loaded from config file,
+* so they can take part in asynchronous saves. For that we're clearing "server.commands",
+* "server.orig_commands", and then only take "loadmodule" directives from main process' config
+* file. This function consists of parts from server.c/main() function.
+*/
+void InitRedisModulesFromConfigFile() {
+#pragma warning( suppress : 6031 )
+    pthread_mutex_init(&lazyfree_objects_mutex, NULL);
+#pragma warning( suppress : 6031 )
+    pthread_mutex_init(&moduleUnblockedClientsMutex, NULL);
+#pragma warning( suppress : 6031 )
+    pthread_mutex_init(&moduleGIL, NULL);
+    moduleInitModulesSystem();
+
+    //re-create commands as the dictionary coming from main process contains commands
+    //  registered by modules, which would prevent them from loading in this child process
+    server.commands = dictCreate(server.commands->type, NULL);
+    server.orig_commands = dictCreate(server.orig_commands->type, NULL);
+    populateCommandTable();
+
+    //read only "loadmodule" directives from config file(s)
+    loadServerConfig(server.configfile, NULL, &ConfigFilterModulesOnly);
+
+    //load modules found in config file(s)
+    moduleLoadFromQueue();
+}
+
 void SetupRedisGlobals(LPVOID redisData, size_t redisDataSize, uint8_t *dictHashSeed, LPVOID redisModules)
 {
 #ifndef NO_QFORKIMPL
     memcpy(&server, redisData, redisDataSize);
     dictSetHashFunctionSeed(dictHashSeed);
-    modules = (dict*) redisModules;
+
+    //WORKAROUND: if main process was started with a config file - it contains modules
+    // to be loaded in this child process, so load them here as well
+    if (server.configfile) {
+        InitRedisModulesFromConfigFile();
+    } else {
+        modules = (dict*)redisModules;
+    }
 #endif
 }
 

src/config.c

@@ -178,7 +178,11 @@ void queueLoadModule(sds path, sds *argv, int argc) {
     listAddNodeTail(server.loadmodule_queue,loadmod);
 }
 
-void loadServerConfigFromString(char *config) {
+#ifdef _WIN32
+void loadServerConfigFromString(char *config, configLineFilter lineFilter) {
+#else
+void loadServerConfigFromString(char* config) {
+#endif
     char *err = NULL;
     int linenum = 0, totlines, i;
     int slaveof_linenum = 0;
@@ -210,6 +214,13 @@ void loadServerConfigFromString(char *config) {
         }
         sdstolower(argv[0]);
 
+#ifdef _WIN32
+        //skip config parameter if "line filter" returns FALSE
+        if (lineFilter && lineFilter(argv[0]) == FALSE) {
+            continue;
+        }
+#endif
+
         /* Execute config directives */
         if (!strcasecmp(argv[0],"timeout") && argc == 2) {
             server.maxidletime = atoi(argv[1]);
@@ -353,7 +364,11 @@ void loadServerConfigFromString(char *config) {
                 err = "Invalid number of databases"; goto loaderr;
             }
         } else if (!strcasecmp(argv[0],"include") && argc == 2) {
+#ifdef _WIN32
+            loadServerConfig(argv[1],NULL,lineFilter);
+#else
             loadServerConfig(argv[1],NULL);
+#endif
         } else if (!strcasecmp(argv[0],"maxclients") && argc == 2) {
             server.maxclients = atoi(argv[1]);
             if (server.maxclients < 1) {
@@ -922,7 +937,11 @@ void loadServerConfigFromString(char *config) {
  * Both filename and options can be NULL, in such a case are considered
  * empty. This way loadServerConfig can be used to just load a file or
  * just load a string. */
-void loadServerConfig(char *filename, char *options) {
+#ifdef _WIN32
+void loadServerConfig(char *filename, char *options, configLineFilter lineFilter) {
+#else
+void loadServerConfig(char* filename, char* options) {
+#endif
     sds config = sdsempty();
     char buf[CONFIG_MAX_LINE+1];
 
@@ -948,7 +967,11 @@ void loadServerConfig(char *filename, char *options) {
         config = sdscat(config,"\n");
         config = sdscat(config,options);
     }
+#ifdef _WIN32
+    loadServerConfigFromString(config,lineFilter);
+#else
     loadServerConfigFromString(config);
+#endif
     sdsfree(config);
 }
 

src/server.c

@@ -4479,7 +4479,11 @@ int main(int argc, char **argv) {
             exit(1);
         }
         resetServerSaveParams();
+#ifdef _WIN32
+        loadServerConfig(configfile,options,NULL);
+#else
         loadServerConfig(configfile,options);
+#endif
         sdsfree(options);
     }
 

src/server.h

@@ -1845,7 +1845,13 @@ int keyspaceEventsStringToFlags(char *classes);
 sds keyspaceEventsFlagsToString(int flags);
 
 /* Configuration */
-void loadServerConfig(char *filename, char *options);
+#ifdef _WIN32
+//callback to include/skip given config file parameter; TRUE = include, FALSE = skip
+typedef int (*configLineFilter)(sds);
+void loadServerConfig(char *filename, char *options, configLineFilter lineFilter);
+#else
+void loadServerConfig(char* filename, char* options);
+#endif
 void appendServerSaveParams(time_t seconds, int changes);
 void resetServerSaveParams(void);
 struct rewriteConfigState; /* Forward declaration to export API. */