recv() - doesn't block?

[TheDarkAvenger]

Hi,
Consider the following code:

#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>


int main(int argc, char *argv[])
{
	struct addrinfo *res, hints;
	int cnt;
	char buffer[] = "GET /intl/en/ HTTP/1.1\r\nHost: www.google.com\r\nX-Header: test\r\n\r\n";
	char buffer_in[1024];

	memset(&hints, 0, sizeof hints);
	hints.ai_family = AF_INET;
	hints.ai_socktype = SOCK_STREAM;

	getaddrinfo("www.google.com", "80", &hints, &res);
	cnt= socket(res->ai_family, res->ai_socktype, res->ai_protocol);
	connect(cnt, res->ai_addr, res->ai_addrlen);

	send(cnt, buffer, 2048, 0);
	while (1){
		if (recv(cnt, buffer_in, 1024, 0) == 0)
			printf("error :P ");
		else
			printf("%s\n", buffer_in);
	}
	close(cnt);
	exit(EXIT_SUCCESS);
}

As far as I can see, socket wasn't set to be non-blocking. However, after receiving data from host, recv() starts returning 0 without waiting for any data. Why is that? In fact, it would be great if this function could wait for some data...
Thanks in advance for your answers.

[Cactus_Hugger]

1) The size you're passing to send() is crap. Pass the size of the data you want to send, not an arbitrary number. Additionally, this is a buffer overflow.

2) The server is probably closing the connection from the invalid data that you're sending. Also, recv() returns <0 on error, 0 on socket close.

3) You risk a buffer overflow by printf()'ing buffer_in without null-terminating it. If you actually get 1024 bytes of data that contains no nulls (not unlikely from a website), then it'll overflow. recv() one less than your buffer size, and write a null at buffer[recv_return_value].

4) Memory leak in *res.

5) Check your return codes on send(), connect() and getaddrinfo() - do they succeed?