From a697835d0fc31297014e997b250aa8a28a013ad7 Mon Sep 17 00:00:00 2001
From: Hang Zhou <hang.zhou@agile-robots.com>
Date: Thu, 12 Sep 2024 18:15:24 +0800
Subject: [PATCH] resolve segment fault and Error on modbus connection

---
 examples/linux/platform.h   | 3 ++-
 examples/linux/server-tcp.c | 2 ++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/examples/linux/platform.h b/examples/linux/platform.h
index 20f037b..f315bfe 100644
--- a/examples/linux/platform.h
+++ b/examples/linux/platform.h
@@ -167,6 +167,7 @@ void disconnect(void* conn) {
 // Read/write/sleep platform functions
 
 int32_t read_fd_linux(uint8_t* buf, uint16_t count, int32_t timeout_ms, void* arg) {
+    if(!arg) return -1;
     int fd = *(int*) arg;
 
     uint16_t total = 0;
@@ -192,7 +193,7 @@ int32_t read_fd_linux(uint8_t* buf, uint16_t count, int32_t timeout_ms, void* ar
             ssize_t r = read(fd, buf + total, 1);
             if (r == 0) {
                 disconnect(arg);
-                return -1;
+                return 0;
             }
 
             if (r < 0)
diff --git a/examples/linux/server-tcp.c b/examples/linux/server-tcp.c
index 89862d2..849a770 100644
--- a/examples/linux/server-tcp.c
+++ b/examples/linux/server-tcp.c
@@ -218,6 +218,8 @@ int main(int argc, char* argv[]) {
         if (conn) {
             // Set the next connection handler used by the read/write platform functions
             nmbs_set_platform_arg(&nmbs, conn);
+        }else{
+            continue;
         }
 
         err = nmbs_server_poll(&nmbs);