How to call a function in a C server from a client - c

Question

I made an application in C that adds structs to a file and now I want to make it work trough sockets, making the client ask the user to submit the fields of the struct and then the server saves it in the file saving a log file for each action made by the client (add,delete,search,etc). How can I do this? also is it possible to call a function residing in the server from the client?
Thanks in advance.

Answer 1

Create socket listener at server and wait for client connection.
When client sends you something, parse it and make the appropriate action.
for example:
/* Create the socket and listen to cennections */
sock = create_socket(port);
if (listen(sock, 1) < 0)
{
perror("listen");
exit(EXIT_FAILURE);
}
/* Never end loop for socket listen */
while(1)
{
/* Accept socket */
newsock = accept(sock, (struct sockaddr *) &peer, &len);
/* dump_sockaddr (peer, len); */
if (newsock >= 0)
{
/* Null-terminate socket buffer */
bzero(buf, MAXMSG);
/* Read from socket */
ret = read(newsock, buf, sizeof(buf));
if (ret > 0)
{
printf("Recieved command: %s\n", buf);
/* Parse command from buffer */
if (strstr(buf, "deletesomethig") != NULL)
{
/* Make the appropriate action */
delete_something();
}
else if (strstr(buf, "stopsomething") != NULL)
{
/* Make the appropriate action */
stop_something();
}
else
printf("Recieved unsupported command: %s\n", buf);
/* Close socket */
close(newsock);
}
}
}
/* Close socket */
close(sock);
Just be sure that strstr() has no trouble with memory. This is simple example, you can use sscanf() for parsing commands from socket buffer.