在Linux下，你可以使用TCP连接的超时机制来判断文件传输是否结束。当客户端发送文件后，服务端需要在一定时间内接收并确认客户端的连接，如果超过这个时间，服务端可以认为文件传输已经结束。

以下是一个简单的示例：

```c

include

include

include

include

include

include

include

define MAX_CONNECTIONS 100

int main(int argc, char *argv[]) { int server_sock, client_sock; struct sockaddr_in server_addr, client_addr; struct sockaddr_in server_addr_in, client_addr_in_in; struct sockaddr_in serv_addr_in, serv_addr_in_in_in; struct iovec iovec_data;

if (argc != 2) {
    printf("Usage: %s <server_ip>\n", argv[0]);
    return 1;
}

server_sock = socket(AF_INET, SOCK_STREAM, 0);
if (server_sock == -1) {
    perror("socket failed");
    return 1;
}

server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(8080);
server_addr.sin_addr.s_addr = INADDR_ANY;

if (bind(server_sock, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
    perror("bind failed");
    return 1;
}

if (listen(server_sock, MAX_CONNECTIONS) == -1) {
    perror("listen failed");
    return 1;
}

while (true) {
    client_sock = accept(server_sock, (struct sockaddr *)&client_addr, sizeof(client_addr));
    if (client_sock == -1) {
        perror("accept failed");
        continue;
    }

    memset(&iov_data, 0, sizeof(iov_data));
   iov_data.iov_size = strlen(argv[1]);

    send(client_sock, argv[1], iov_data.iov_size, 0);
    char buf[1024];
    recv(client_sock, buf, sizeof(buf), 0);
    if (recv(client_sock, "\n", sizeof("\n"), 0) == -1) {
        perror("recv failed");
        continue;
    }
    printf("Received: %s\n", buf);

    // Check for file transfer结束
    iovec_data.iov_base = buf;
    iovec_data.iov_size =iov_data.iov_size - 1;
    if (send(client_sock, &iov_data, sizeof(iov_data), 0) == -1) {
        perror("send failed");
        continue;
    }

    if (recv(client_sock, "\n", sizeof("\n"), 0) == -1) {
        perror("recv failed");
        continue;
    }
    printf("Received: %s\n", buf);

    if (strcmp(server_addr.sin_addr.s_addr, INADDR_ANY) != 0) {
        close(client_sock);
        break;
    }
}

close(server_sock);

return 0;

} ```

在这个示例中，服务端监听8080端口，当有客户端连接时，它会读取客户端发送的文件内容，然后检查客户端发送的文件结束符，如果与服务端的地址不匹配，服务端会关闭客户端连接，然后结束整个文件传输。