sock.c

//License: Apache License 2.0
//See LICENSE for details
//Authors (in alphabet order of last name):
// - Qijiang Fan <fqj1994@gmail.com>
// - Bin He <binhe22@gmail.com>
// - Cheng Zhang <chengzhang@hustunique.com>
// - Shiwei Zhou <shwzhou@hustunique.com>
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include "sock.h"

/*****************************************
* Function: sock_daemon_connect
*****************************************/
int sock_daemon_connect(int port)
{
	struct addrinfo *res, *t;
	struct addrinfo hints = {
		.ai_flags = AI_PASSIVE,
		.ai_family = AF_UNSPEC,
		.ai_socktype = SOCK_STREAM
	};
	char *service;
	int n;
	int sockfd = -1, connfd;

	if (asprintf(&service, "%d", port) < 0) {
		fprintf(stderr, "asprintf failed\n");
		return -1;
	}

	n = getaddrinfo(NULL, service, &hints, &res);
	if (n < 0) {
		fprintf(stderr, "%s for port %d\n", gai_strerror(n), port);
		free(service);
		return -1;
	}

	for (t = res; t; t = t->ai_next) {
		sockfd = socket(t->ai_family, t->ai_socktype, t->ai_protocol);
		if (sockfd >= 0) {
			n = 1;

			setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &n,
				   sizeof n);

			if (!bind(sockfd, t->ai_addr, t->ai_addrlen))
				break;
			close(sockfd);
			sockfd = -1;
		}
	}

	freeaddrinfo(res);
	free(service);

	if (sockfd < 0) {
		fprintf(stderr, "couldn't listen to port %d\n", port);
		return -1;
	}

	listen(sockfd, 1);
	connfd = accept(sockfd, NULL, 0);
	close(sockfd);
	if (connfd < 0) {
		fprintf(stderr, "accept() failed\n");
		return -1;
	}

	return connfd;
}

/*****************************************
* Function: sock_client_connect
*****************************************/
int sock_client_connect(const char *server_name, int port)
{
	struct addrinfo *res, *t;
	struct addrinfo hints = {
		.ai_family = AF_UNSPEC,
		.ai_socktype = SOCK_STREAM
	};
	char *service;
	int n;
	int sockfd = -1;

	if (asprintf(&service, "%d", port) < 0) {
		fprintf(stderr, "asprintf failed\n");
		return -1;
	}

	n = getaddrinfo(server_name, service, &hints, &res);
	if (n < 0) {
		fprintf(stderr, "%s for %s:%d\n", gai_strerror(n), server_name,
			port);
		free(service);
		return -1;
	}

	for (t = res; t; t = t->ai_next) {
		sockfd = socket(t->ai_family, t->ai_socktype, t->ai_protocol);
		if (sockfd >= 0) {
			if (!connect(sockfd, t->ai_addr, t->ai_addrlen))
				break;
			close(sockfd);
			sockfd = -1;
		}
	}
	freeaddrinfo(res);
	free(service);

	if (sockfd < 0) {
		//fprintf(stderr, "couldn't connect to %s:%d\n", server_name,
	//		port);
		return -1;
	}

	return sockfd;
}

/*****************************************
* Function: sock_recv
*****************************************/
static int sock_recv(int sock_fd, size_t size, void *buf)
{
	int rc;

      retry_after_signal:
	rc = recv(sock_fd, buf, size, MSG_WAITALL);
	if (rc != size) {
		fprintf(stderr, "recv failed: %s, rc=%d\n", strerror(errno),
			rc);

		if ((errno == EINTR) && (rc != 0))
			goto retry_after_signal;	/* Interrupted system call */
		if (rc)
			return rc;
		else
			return -1;
	}

	return 0;
}

/*****************************************
* Function: sock_send
*****************************************/
static int sock_send(int sock_fd, size_t size, const void *buf)
{
	int rc;

      retry_after_signal:
	rc = send(sock_fd, buf, size, 0);

	if (rc != size) {
		fprintf(stderr, "send failed: %s, rc=%d\n", strerror(errno),
			rc);

		if ((errno == EINTR) && (rc != 0))
			goto retry_after_signal;	/* Interrupted system call */
		if (rc)
			return rc;
		else
			return -1;
	}

	return 0;
}

/*****************************************
* Function: sock_sync_data
*****************************************/
int sock_sync_data(int sock_fd,
		   int is_daemon,
		   size_t size, const void *out_buf, void *in_buf)
{
	int rc;

	if (!is_daemon) {
		rc = sock_send(sock_fd, size, out_buf);
		if (rc)
			return rc;

		rc = sock_recv(sock_fd, size, in_buf);
		if (rc)
			return rc;
	} else {
		rc = sock_recv(sock_fd, size, in_buf);
		if (rc)
			return rc;

		rc = sock_send(sock_fd, size, out_buf);
		if (rc)
			return rc;
	}

	return 0;
}

/*****************************************
* Function: sock_sync_ready
*****************************************/
int sock_sync_ready(int sock_fd, int is_daemon)
{
	char cm_buf = 'a';

	return sock_sync_data(sock_fd, is_daemon, sizeof(cm_buf), &cm_buf,
			      &cm_buf);
}