[fix]修正死循环。网络层收不到数据时，ReceiveCommand可能进入无限死循环

NewLifeX · Apr 26, 2024 · 78ee7e4 · 78ee7e4
1 parent 48044f4
commit 78ee7e4
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Showing 3 changed files with 16 additions and 9 deletions.
diff --git a/NewLife.Modbus/Protocols/ModbusIp.cs b/NewLife.Modbus/Protocols/ModbusIp.cs
@@ -89,19 +89,22 @@ protected virtual Packet ReceiveCommand()
     {
         // 设置协议最短长度，避免读取指令不完整。由于请求响应机制，不存在粘包返回。
         var dataLength = 8; // 2+2+2+1+1
-        var count = 0;
         Packet pk = null;
-        while (count < dataLength)
+        for (var i = 0; i < 8; i++)
         {
+            // 阻塞读取
             var pk2 = _client.Receive();
+            if (pk2 == null || pk2.Total == 0) continue;
+
             if (pk == null)
                 pk = pk2;
             else
                 pk.Append(pk2);
 
             // 已取得请求头，计算真实长度
-            count = pk.Total;
+            var count = pk.Total;
             if (count >= 6) dataLength = pk.ReadBytes(4, 2).ToUInt16(0, false);
+            if (count >= dataLength) break;
         }
 
         return pk;

diff --git a/NewLife.Modbus/Protocols/ModbusRtuOverTcp.cs b/NewLife.Modbus/Protocols/ModbusRtuOverTcp.cs
@@ -25,17 +25,19 @@ protected override Packet ReceiveCommand()
     {
         // 设置协议最短长度，避免读取指令不完整。由于请求响应机制，不存在粘包返回。
         var dataLength = 4; // 1+1+2
-        var count = 0;
         Packet pk = null;
-        while (count < dataLength)
+        for (var i = 0; i < 3; i++)
         {
+            // 阻塞读取
             var pk2 = _client.Receive();
+            if (pk2 == null || pk2.Total == 0) continue;
+
             if (pk == null)
                 pk = pk2;
             else
                 pk.Append(pk2);
 
-            count = pk.Total;
+            if (pk.Total >= dataLength) break;
         }
 
         return pk;

diff --git a/NewLife.Modbus/Protocols/ModbusRtuOverUdp.cs b/NewLife.Modbus/Protocols/ModbusRtuOverUdp.cs
@@ -25,17 +25,19 @@ protected override Packet ReceiveCommand()
     {
         // 设置协议最短长度，避免读取指令不完整。由于请求响应机制，不存在粘包返回。
         var dataLength = 4; // 1+1+2
-        var count = 0;
         Packet pk = null;
-        while (count < dataLength)
+        for (var i = 0; i < 3; i++)
         {
+            // 阻塞读取
             var pk2 = _client.Receive();
+            if (pk2 == null || pk2.Total == 0) continue;
+
             if (pk == null)
                 pk = pk2;
             else
                 pk.Append(pk2);
 
-            count = pk.Total;
+            if (pk.Total >= dataLength) break;
         }
 
         return pk;