Recovering IP/Port from Socket Descriptor

Question

I\'m writing a clone of inetd in which I must run a server that prints the IP and port of the client connecting to it.

As I overwrite STDIN and S

Answer 1

Use getpeername. I suspect your problem is that getsockname is returning the information for your own (local) side of the socket, which is probably bound to 0.0.0.0 (meaning it can accept connections from any interface).

Edit: I think I found your actual bug reading the code. This line is wrong:

getsockname(stdin, &addr, sizeof(addr));

The getsockname and getpeername functions take a socklen_t * (a pointer) as their third argument, not a size_t. The compiler should be telling you about this mistake unless you forgot to include a header with the prototype for getsockname. Also, as has already been said, stdin is incorrect. Try:

socklen_t len = sizeof addr;
getpeername(0, &addr, &len);

or (C99 only):

getpeername(0, &addr, (socklen_t[1]){sizeof addr});

You should also be checking the return value; if you did, you'd see that it's returning errors.