Unix域套接字(C++）-客户端使服务器守护进程崩溃

我遇到了一个很大的问题
我最近开始了守护进程和套接字编程。我当前的设置由一个创建套接字的守护进程和一个写入消息并读取处理后的答案的客户端组成
嗯，应该阅读答案。

守护进程对自己进行守护，创建套接字，甚至处理消息(我可以通过我创建的日志条目进行验证)，但一旦我试图向客户端发送答案，守护进程就会被阻止；客户端从未接收到应答，并且如果Ictrl-c客户端，则守护进程也将关闭
这对我来说完全是一种奇怪的行为，我无法解释发生了什么，这就是为什么我问你任何暗示。

简要总结：
-套接字类型为AF_UNIX，因此是本地的，不涉及网络
-守护进程成功接收到消息，但无法写回
–客户端无法读取(因为服务器的send()正在阻塞)和如果我ctrl-c客户端，守护进程也会退出(但该信号不会发送给守护进程)

下面是我的代码，精简到有趣且不起作用的部分
非常感谢您的提示、帮助和建议！

更新：

还添加了客户端代码！

int main()
{
//those two work just fine
createSocket();
daemonize();
//declare some variables needed in the big loop
FILE *client_fd;
int fd;
socklen_t len;
string tmp;
char *buf = new char[1024];
while(1)
{
struct sockaddr_un saun;
len = sizeof(saun);
//receive an fd for the incoming connection
if((fd = accept(m_socket, (sockaddr*)&saun, &len)) < 0)
{
writeLog("Accepting connection failed!");
continue;
}
//i wanted to use fgets, therefore obtain a FILE object here
client_fd = fdopen(fd, "r");
if(client_fd == NULL)
{
writeLog("fdopen() failed!");
continue;
}
while(fgets(buf, bufferSize, client_fd) != NULL)
{
//message read succeeds (verified)
writeLog(buf);
tmp = evaluateMsg(buf);
//tmp is not empty (verified)
writeLog(tmp);
//send seems to block, nothing happens from now on
//I don't even get in one of the if-else branches
if(send(fd, (tmp + "n").c_str(), tmp.size() + 1, 0) < 0)
{
writeLog("Could not write message back!");
continue;
}
else
writeLog("bytes written!");
}
close(fd);
}
}

以下是客户端代码：

int main()
{
int sockfd;
sockaddr_un addr;
sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
addr.sun_family = AF_UNIX;
strcpy(addr.sun_path, SOCKET_PATH);
//the connection is successfull
if(connect(sockfd, (sockaddr*)&addr, sizeof(addr)) < 0)
{
cerr<<"Connection failed!"<<endl;
exit(1);
}
//message is written successfully
write(sockfd, "hello", 5);
char *buf = new char[1024];
//same as for the server, I wanted to use fgets
//therefore need to obtain a FILE object
FILE *fd = fdopen(sockfd, "r");
fgets(buf, 1024, fd);
cout<<buf<<endl;
close(sockfd);
}