client.c

/*
 * Copyright 2015-2018 Rivoreo
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 */

#include "common.h"
#include "client.h"
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#define MAX(A,B) ((A)>(B)?(A):(B))
#define REMOTE_MODE_CLI 1
#define REMOTE_MODE_API 2

static int send_login(int fd, const char *orig_user_name, const char *client_address) {
	int r = 0;
	size_t user_name_len = strlen(orig_user_name);
	//char user_name[USER_NAME_MAX_LENGTH];
	if(user_name_len > USER_NAME_MAX_LENGTH - 1) user_name_len = USER_NAME_MAX_LENGTH - 1;
	//memcpy(user_name, orig_user_name, user_name_len);
	//memset(user_name + user_name_len, 0, USER_NAME_MAX_LENGTH - user_name_len);
	const char *space = strchr(client_address, ' ');
	size_t host_name_len = space ? space - client_address : strlen(client_address);
	if(host_name_len > HOST_NAME_MAX_LENGTH) host_name_len = HOST_NAME_MAX_LENGTH;
	//char host_name[host_name_len + 1];
	//memcpy(host_name, client_address, host_name_len);
	//host_name[host_name_len] = 0;
	size_t packet_len = sizeof(struct local_packet) + USER_NAME_MAX_LENGTH + host_name_len;
	struct local_packet *packet = malloc(packet_len);
	if(!packet) return -1;
	packet->length = packet_len - sizeof packet->length;
	packet->type = SSHOUT_LOCAL_LOGIN;
	memcpy(packet->data, orig_user_name, user_name_len);
	memset(packet->data + user_name_len, 0, USER_NAME_MAX_LENGTH - user_name_len);
	char *host_name = packet->data + USER_NAME_MAX_LENGTH;
	memcpy(host_name, client_address, host_name_len);
	host_name[host_name_len] = 0;
	while(write(fd, packet, packet_len) < 0) {
		if(errno == EINTR) continue;
		r = -1;
		break;
	}
	int e = errno;
	free(packet);
	errno = e;
	return r;
}

int client_send_request_get_online_users(int fd) {
	struct local_packet packet;
	packet.length = sizeof packet - sizeof packet.length;
	packet.type = SSHOUT_LOCAL_GET_ONLINE_USERS;
	while(write(fd, &packet, sizeof packet) < 0) {
		if(errno == EINTR) continue;
		return -1;
	}
	return 0;
}

// field msg_from is not needed
int client_post_message(int fd, const struct local_message *message) {
	int r = 0;
	size_t packet_len = sizeof(struct local_packet) + sizeof(struct local_message) + message->msg_length;
	struct local_packet *packet = malloc(packet_len);
	if(!packet) return -1;
	packet->length = packet_len - sizeof packet->length;
	packet->type = SSHOUT_LOCAL_POST_MESSAGE;
	memcpy(packet->data, message, sizeof(struct local_message) + message->msg_length);
	while(write(fd, packet, packet_len) < 0) {
		if(errno == EINTR) continue;
		r = -1;
		break;
	}
	int e = errno;
	free(packet);
	errno = e;
	return r;
}

int client_post_plain_text_message(int fd, const char *receiver, const char *text) {
	size_t receiver_len = strlen(receiver);
	size_t text_len = strlen(text);
	struct local_message *message = malloc(sizeof(struct local_message) + text_len);
	if(!message) return -1;
	if(receiver_len > USER_NAME_MAX_LENGTH - 1) receiver_len = USER_NAME_MAX_LENGTH - 1;
	memcpy(message->msg_to, receiver, receiver_len);
	message->msg_to[receiver_len] = 0;
	message->msg_type = SSHOUT_MSG_PLAIN;
	message->msg_length = text_len;
	memcpy(message->msg, text, text_len);
	int r = client_post_message(fd, message);
	free(message);
	return r;
}

int client_mode(const struct sockaddr_un *socket_addr, const char *user_name) {
	int remote_mode = REMOTE_MODE_CLI;
	const char *client_address = getenv("SSH_CLIENT");
	if(!client_address) {
		fputs("client mode can only be used in a SSH session\n", stderr);
		return 1;
	}
	const char *command = getenv("SSH_ORIGINAL_COMMAND");
	if(command) {
		if(strcmp(command, "api") == 0) remote_mode = REMOTE_MODE_API;
		else {
			fprintf(stderr, "Command '%s' is not recognized\n", command);
			return 1;
		}
	}
	int fd = socket(AF_UNIX, SOCK_STREAM, 0);
	if(fd == -1) {
		perror("socket");
		return 1;
	}
	while(connect(fd, (struct sockaddr *)socket_addr, sizeof(struct sockaddr_un)) < 0) {
		if(errno == EINTR) continue;
		perror("connect");
		return 1;
	}

	if(remote_mode != REMOTE_MODE_CLI) {
		fputs("This remote mode is currently not implemented\n", stderr);
		return 1;
	}

	send_login(fd, user_name, client_address);

	fd_set fdset;
	FD_ZERO(&fdset);
	FD_SET(fd, &fdset);
	FD_SET(STDIN_FILENO, &fdset);
	int maxfd = MAX(fd, STDIN_FILENO);

	void (*client_do_local_packet)(int);
	void (*client_do_stdin)(int);
	if(remote_mode == REMOTE_MODE_CLI) {
		client_cli_init_stdin();
		client_do_local_packet = client_cli_do_local_packet;
		client_do_stdin = client_cli_do_stdin;
	}

	while(1) {
		fd_set rfdset = fdset;
		if(select(maxfd + 1, &rfdset, NULL, NULL, NULL) < 0) {
			if(errno == EINTR) continue;
			perror("select");
		}
		if(FD_ISSET(fd, &rfdset)) client_do_local_packet(fd);
		if(FD_ISSET(STDIN_FILENO, &fdset)) client_do_stdin(fd);
	}
}