fix defect found in coverity scan

src/mnode/src/mnodeDb.c

@@ -67,8 +67,11 @@ static int32_t mnodeDbActionInsert(SSdbOper *pOper) {
   SAcctObj *pAcct = mnodeGetAcct(pDb->acct);
 
   pthread_mutex_init(&pDb->mutex, NULL);
+  pthread_mutex_lock(&pDb->mutex);
   pDb->vgListSize = VG_LIST_SIZE;
   pDb->vgList = calloc(pDb->vgListSize, sizeof(SVgObj *));
+  pthread_mutex_unlock(&pDb->mutex);
+
   pDb->numOfVgroups = 0;
   pDb->numOfTables = 0;
   pDb->numOfSuperTables = 0;
@@ -395,8 +398,8 @@ static int32_t mnodeCreateDb(SAcctObj *pAcct, SCMCreateDbMsg *pCreate, void *pMs
 
   code = sdbInsertRow(&oper);
   if (code != TSDB_CODE_SUCCESS) {
-    mnodeDestroyDb(pDb);
     mLInfo("db:%s, failed to create, reason:%s", pDb->name, tstrerror(code));
+    mnodeDestroyDb(pDb);
     return code;
   } else {
     return TSDB_CODE_MND_ACTION_IN_PROGRESS;
@@ -605,7 +608,9 @@ static int32_t mnodeGetDbMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn
 
 static char *mnodeGetDbStr(char *src) {
   char *pos = strstr(src, TS_PATH_DELIMITER);
-  return ++pos;
+  if (pos != NULL) ++pos;
+
+  return pos;
 }
 
 static int32_t mnodeRetrieveDbs(SShowObj *pShow, char *data, int32_t rows, void *pConn) {
@@ -622,10 +627,13 @@ static int32_t mnodeRetrieveDbs(SShowObj *pShow, char *data, int32_t rows, void
 
     cols = 0;
 
-    pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;
-    
+    pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;  
     char* name = mnodeGetDbStr(pDb->name);
-    STR_WITH_MAXSIZE_TO_VARSTR(pWrite, name, pShow->bytes[cols]);
+    if (name != NULL) {
+      STR_WITH_MAXSIZE_TO_VARSTR(pWrite, name, pShow->bytes[cols]);
+    } else {
+      STR_TO_VARSTR(pWrite, "NULL");
+    }
     cols++;
 
     pWrite = data + pShow->offset[cols] * rows + pShow->bytes[cols] * numOfRows;

src/mnode/src/mnodeSdb.c

@@ -453,7 +453,7 @@ static int32_t sdbInsertHash(SSdbTable *pTable, SSdbOper *pOper) {
     keySize = strlen((char *)key);
   }
 
-  taosHashPut(pTable->iHandle, key, keySize, &pOper->pObj, sizeof(void **));
+  taosHashPut(pTable->iHandle, key, keySize, &pOper->pObj, sizeof(int64_t));
 
   sdbIncRef(pTable, pOper->pObj);
   atomic_add_fetch_32(&pTable->numOfRows, 1);

src/mnode/src/mnodeVgroup.c

@@ -434,15 +434,22 @@ int32_t mnodeGetAvailableVgroup(SMnodeMsg *pMsg, SVgObj **ppVgroup, int32_t *pSi
   }
 
   if (pDb->numOfVgroups < maxVgroupsPerDb) {
-    mDebug("app:%p:%p, db:%s, try to create a new vgroup, numOfVgroups:%d maxVgroupsPerDb:%d", pMsg->rpcMsg.ahandle, pMsg,
-           pDb->name, pDb->numOfVgroups, maxVgroupsPerDb);
+    mDebug("app:%p:%p, db:%s, try to create a new vgroup, numOfVgroups:%d maxVgroupsPerDb:%d", pMsg->rpcMsg.ahandle,
+           pMsg, pDb->name, pDb->numOfVgroups, maxVgroupsPerDb);
     pthread_mutex_unlock(&pDb->mutex);
     int32_t code = mnodeCreateVgroup(pMsg);
-    if (code == TSDB_CODE_MND_ACTION_IN_PROGRESS) return code;
+    if (code == TSDB_CODE_MND_ACTION_IN_PROGRESS) {
+      return code;
+    } else {
+      pthread_mutex_lock(&pDb->mutex);
+    }
   }
 
   SVgObj *pVgroup = pDb->vgList[0];
-  if (pVgroup == NULL) return TSDB_CODE_MND_NO_ENOUGH_DNODES;
+  if (pVgroup == NULL) {
+    pthread_mutex_unlock(&pDb->mutex);
+    return TSDB_CODE_MND_NO_ENOUGH_DNODES;
+  }
 
   int32_t code = mnodeAllocVgroupIdPool(pVgroup);
   if (code != TSDB_CODE_SUCCESS) {
@@ -483,7 +490,7 @@ static int32_t mnodeCreateVgroupCb(SMnodeMsg *pMsg, int32_t code) {
   } else {
     pVgroup->status = TAOS_VG_STATUS_READY;
     SSdbOper desc = {.type = SDB_OPER_GLOBAL, .pObj = pVgroup, .table = tsVgroupSdb};
-    sdbUpdateRow(&desc);
+    (void)sdbUpdateRow(&desc);
   }
 
   mInfo("app:%p:%p, vgId:%d, is created in mnode, db:%s replica:%d", pMsg->rpcMsg.ahandle, pMsg, pVgroup->vgId,

src/plugins/http/src/gcJson.c

@@ -121,6 +121,10 @@ bool gcBuildQueryJson(HttpContext *pContext, HttpSqlCmd *cmd, TAOS_RES *result,
 
   for (int k = 0; k < numOfRows; ++k) {
     TAOS_ROW row = taos_fetch_row(result);
+    if (row == NULL) {
+      cmd->numOfRows--;
+      continue;
+    }
     int32_t* length = taos_fetch_lengths(result);
 
     // for group by

src/plugins/http/src/httpContext.c

@@ -108,7 +108,7 @@ HttpContext *httpCreateContext(int32_t fd) {
   pContext->lastAccessTime = taosGetTimestampSec();
   pContext->state = HTTP_CONTEXT_STATE_READY;
 
-  HttpContext **ppContext = taosCachePut(tsHttpServer.contextCache, &pContext, sizeof(void *), &pContext, sizeof(void *), 3);
+  HttpContext **ppContext = taosCachePut(tsHttpServer.contextCache, &pContext, sizeof(int64_t), &pContext, sizeof(int64_t), 3);
   pContext->ppContext = ppContext;
   httpDebug("context:%p, fd:%d, is created, data:%p", pContext, fd, ppContext);
 

src/plugins/http/src/restJson.c

@@ -94,6 +94,10 @@ bool restBuildSqlJson(HttpContext *pContext, HttpSqlCmd *cmd, TAOS_RES *result,
 
   for (int k = 0; k < numOfRows; ++k) {
     TAOS_ROW row = taos_fetch_row(result);
+    if (row == NULL) {
+      cmd->numOfRows--;
+      continue;
+    }
     int32_t* length = taos_fetch_lengths(result);
 
     // data row array begin

src/plugins/mqtt/src/mqttSystem.c

@@ -64,7 +64,7 @@ int32_t mqttInitSystem() {
   }
 
   char* _begin_hostname = strstr(url, recntStatus.hostname);
-  if (strstr(_begin_hostname, ":") != NULL) {
+  if (_begin_hostname != NULL && strstr(_begin_hostname, ":") != NULL) {
     recntStatus.port = strbetween(_begin_hostname, ":", "/");
   } else {
     recntStatus.port = strbetween("'1883'", "'", "'");