DB: Make connection initialization more predictable and avoid double-initialization

Remove calls to zmDBConnect from various places to avoid possible side-effects/double initialization.
The function should be called once from the main thread of the daemon.

Also split config loading into 2 steps: static and DB config loading. Load the static config before zmDBConnect is called so it has a chance to succeed.

src/zm_config.cpp

@@ -30,8 +30,7 @@
 // set the relevant ENV vars because the logger gets it's setting from the 
 // config.
 
-void zmLoadConfig() {
-
+void zmLoadStaticConfig() {
   // Process name, value pairs from the main config file first
   process_configfile(ZM_CONFIG);
 
@@ -58,9 +57,11 @@ void zmLoadConfig() {
     globfree(&pglob);
     closedir(configSubFolder);
   }
+}
 
-  if ( !zmDbConnect() ) {
-    Fatal("Can't connect to db. Can't continue.");
+void zmLoadDBConfig() {
+  if ( !zmDbConnected ) {
+    Fatal("Not connected to the database. Can't continue.");
   }
   config.Load();
   config.Assign();

src/zm_config.h

@@ -53,7 +53,8 @@
 #define ZM_SAMPLE_RATE      int(1000000/ZM_MAX_FPS) // A general nyquist sample frequency for delays etc
 #define ZM_SUSPENDED_RATE     int(1000000/4) // A slower rate for when disabled etc
 
-extern void zmLoadConfig();
+void zmLoadStaticConfig();
+void zmLoadDBConfig();
 
 extern void process_configfile(char const *configFile);
 

src/zm_db.h

@@ -43,6 +43,8 @@ class zmDbRow {
 extern MYSQL dbconn;
 extern RecursiveMutex db_mutex;
 
+extern bool zmDbConnected;
+
 bool zmDbConnect();
 void zmDbClose();
 

src/zm_logger.cpp

@@ -342,7 +342,7 @@ Logger::Level Logger::databaseLevel(Logger::Level databaseLevel) {
     databaseLevel = limit(databaseLevel);
     if ( mDatabaseLevel != databaseLevel ) {
       if ( (databaseLevel > NOLOG) && (mDatabaseLevel <= NOLOG) ) { // <= NOLOG would be NOOPT
-        if ( !zmDbConnect() ) {
+        if ( !zmDbConnected ) {
           databaseLevel = NOLOG;
         }
       }  // end if ( databaseLevel > NOLOG && mDatabaseLevel <= NOLOG )

src/zmc.cpp

@@ -181,7 +181,9 @@ int main(int argc, char *argv[]) {
   }
 
   logInit(log_id_string);
-  zmLoadConfig();
+  zmLoadStaticConfig();
+  zmDbConnect();
+  zmLoadDBConfig();
   logInit(log_id_string);
 
   hwcaps_detect();

src/zms.cpp

@@ -81,9 +81,12 @@ int main(int argc, const char *argv[], char **envp) {
     nph = true;
   }
 
-  zmLoadConfig();
   char log_id_string[32] = "zms";
   logInit(log_id_string);
+  zmLoadStaticConfig();
+  zmDbConnect();
+  zmLoadDBConfig();
+
   for (char **env = envp; *env != 0; env++) {
     char *thisEnv = *env;
     Debug(1, "env: %s", thisEnv);

src/zmu.cpp

@@ -417,8 +417,10 @@ int main(int argc, char *argv[]) {
   }
   //printf( "Monitor %d, Function %d\n", mon_id, function );
 
-  zmLoadConfig();
-
+  logInit("zmu");
+  zmLoadStaticConfig();
+  zmDbConnect();
+  zmLoadDBConfig();
   logInit("zmu");
 
   zmSetDefaultTermHandler();