sock.h
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sock.h
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	#include <sys/socket.h>
	#include <netdb.h>

	/*
	* Find and return the port number of a host:port pair, shortening
	* the original string to include only the hostname.
	*/
	static inline int parse_port(char s, unsigned len)
	{
	char p = memchr(s, ':', len);
	if (!p \|\| p == s \|\| p - s == *len)
	return -1;
	*len = p - s;
	return atoi(p + 1);
	}

	/*
	* Dumbed down interface for opening an IPv4 connection.
	*/
	static inline int open_socket(char *name, unsigned port)
	{
	struct sockaddr_in addr = { .sin_family = AF_INET, .sin_port = htons(port) };
	struct hostent *host;
	int sock;

	if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
	error("Can't get socket");
	if (!(host = gethostbyname(name)))
	-h_errno;
	memcpy(&addr.sin_addr.s_addr, host->h_addr, host->h_length);
	if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0)
	return -errno;
	return sock;
	}

	/*
	* Pass a fd over a local socket connection. You have to send some stream
	* data as well, just to make an ugly interface even more irritating.
	*/
	int send_fd(int sock, int fd, char *bogus, unsigned len)
	{
	char payload[CMSG_SPACE(sizeof(int))];
	struct msghdr msg = {
	.msg_control = payload,
	.msg_controllen = sizeof(payload),
	.msg_iov = &(struct iovec){ .iov_base = bogus, .iov_len = len },
	.msg_iovlen = 1,
	};
	struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);

	*cmsg = (struct cmsghdr){ CMSG_LEN(sizeof(int)), SOL_SOCKET, SCM_RIGHTS };
	((int )CMSG_DATA(cmsg)) = fd; // this is really an array, .cmsg_len gives count (??)

	return sendmsg(sock, &msg, 0) != len? -EIO: len;
	}