fix: fix mbs2ucs4 crash issue in taosd

include/os/osString.h

@@ -62,7 +62,6 @@ typedef int32_t TdUcs4;
 int32_t taosUcs4len(TdUcs4 *ucs4);
 int64_t taosStr2int64(const char *str);
 
-int32_t taosConvInit(int32_t maxNum);
 void    taosConvDestroy();
 int32_t taosUcs4ToMbs(TdUcs4 *ucs4, int32_t ucs4_max_len, char *mbs);
 bool    taosMbsToUcs4(const char *mbs, size_t mbs_len, TdUcs4 *ucs4, int32_t ucs4_max_len, int32_t *len);

source/client/src/clientEnv.c

@@ -361,8 +361,6 @@ void taos_init_imp(void) {
 
   initQueryModuleMsgHandle();
 
-  taosConvInit(256);
-  
   rpcInit();
 
   SCatalogCfg cfg = {.maxDBCacheNum = 100, .maxTblCacheNum = 100};

source/dnode/mgmt/node_mgmt/src/dmMgmt.c

@@ -215,6 +215,7 @@ void dmCleanupDnode(SDnode *pDnode) {
   dmClearVars(pDnode);
   rpcCleanup();
   indexCleanup();
+  taosConvDestroy();
   dDebug("dnode is closed, ptr:%p", pDnode);
 }
 

source/os/src/osString.c

@@ -143,14 +143,17 @@ SConv *gConv = NULL;
 int32_t convUsed = 0;
 int32_t gConvMaxNum = 0;
 
-int32_t taosConvInit(int32_t maxNum) {
-  gConvMaxNum = maxNum * 2;
+void taosConvInitImpl(void) {
+  gConvMaxNum = 512;
   gConv = taosMemoryCalloc(gConvMaxNum, sizeof(SConv));
   for (int32_t i = 0; i < gConvMaxNum; ++i) {
     gConv[i].conv = iconv_open(DEFAULT_UNICODE_ENCODEC, tsCharset);
   }
+}
 
-  return 0;
+static TdThreadOnce convInit = PTHREAD_ONCE_INIT;
+void taosConvInit() {
+  taosThreadOnce(&convInit, taosConvInitImpl);
 }
 
 void taosConvDestroy() {
@@ -162,10 +165,7 @@ void taosConvDestroy() {
 
 void taosAcquireConv(int32_t *idx) {
   if (0 == gConvMaxNum) {
-    gConv = taosMemoryCalloc(1, sizeof(SConv));
-    gConv[0].conv = iconv_open(DEFAULT_UNICODE_ENCODEC, tsCharset);
-    *idx = 0;
-    return;
+    taosConvInit();
   }
   
   while (true) {