问题

代码

开了一个子进程来发送文件，发送完毕之后就 close 了 client_data_socket (数据 socket )

// 非阻塞

set_flag(client_data_socket, O_NONBLOCK);

pid_t pid;

if ((pid = fork()) < 0) {

printf("fork error");

continue;

} else if (pid == 0) {

FILE *fp;

if ((fp = fopen(filename, "rb")) == NULL)

{

close(client_data_socket);

printf("open file failed\n");

exit(1);

}

size_t char_size = sizeof(char);

char data_buffer[FILE_READ_BUFFER_SIZE];

int numread;

for (;;)

{

bzero(data_buffer, FILE_READ_BUFFER_SIZE);

numread = fread(data_buffer, char_size, FILE_READ_BUFFER_SIZE, fp);

if (numread < 0)

{

printf("read file failed\n");

break;

}

else if (numread > 0)

{

int length = send(client_data_socket, data_buffer, numread, 0);

if (length == 0)

{

break;

}

else if (length < 0)

{

if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)

{

continue;

}

printf("[PUT] command send data failed\n");

exit(1);

}

}

if (numread == FILE_READ_BUFFER_SIZE) continue;

else {

break;

}

}

close(client_data_socket);

fclose(fp);

exit(0);

} else {

int status = 0;

waitpid(pid, &status, 0);

if (status == 0)

printf("send file %s complete.\n", filename);

else

printf("send file %s failed.\n", filename);

}

然后，发送别的命令在 recv 的时候，命令端 socket 就阻塞了

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