修复导致cpu使用率高的bug

net_uart.cpp

@@ -70,6 +70,10 @@ void *netclient_thread(void *arg) {
   char buff[4096];
   int n = 0;
   while ((n = read(client->fd, buff, 4096)) >= 0) {
+    if (n == 0) {
+      //返回零意味着对方关闭socket,超时返回的是负数
+      break;
+    }
     printf("net->uart: %d\n", n);
     printf_buf(buff, n);
     uartSend(&g_uart_device, buff, n);

uart.cpp

@@ -84,7 +84,7 @@ int uartStart(struct UartDevice* dev, unsigned char canonic) {
     /* set input mode (non-canonical, no echo,...) */
     tty->c_lflag = 0;
     /* Do not wait for data */
-    tty->c_cc[VTIME] = 0; /* inter-character timer unused */
+    tty->c_cc[VTIME] = 10; /* inter-character timer unused */
     tty->c_cc[VMIN] = 0;  /* blocking read until 5 chars received */
   }