handlers.c

/*
 * handlers.c
 *
 *  Created on: Nov 23, 2012
 *      Author: ivo
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <poll.h>
#include "handlers.h"
#include "serve.h"
#include "kftp.h"

int create_data_sock(client * this_client) {
	socklen_t addrlen = sizeof(struct sockaddr);
	serv_conf * data_conf = malloc(sizeof(serv_conf));
	int clientsock;
	data_conf->backlog = 1;
	data_conf->maxconn = 1;
	data_conf->port = 0;
	this_client->session.data_sock = create_serv_socket(data_conf);
	if (this_client->session.data_sock == -1)
		return -1;
	getsockname(this_client->session.data_sock, (struct sockaddr *) &(this_client->session.data_addr), &addrlen);
	free(data_conf);
	return 0;
}

void handler_fun_user(client * this_client, char * args) {
	LOG("Client %d user %s\n", this_client->id, args);
	strncpy(this_client->session.user, args, 63);
	send(((client *) this_client)->sock,"331 OK\n",7,0);
}

void handler_fun_pass(client * this_client, char * args) {
	LOG("Client %d pass %s\n", this_client->id, args);
	strncpy(this_client->session.pass, args, 63);
	send(((client *) this_client)->sock,"230 OK\n",7,0);
	this_client->session.auth = 1;
}

void handler_fun_pwd(client * this_client, char * args) {
	char msg[260];
	sprintf(msg, "257 \"%s\"\n", this_client->session.pwd);
	send(((client *) this_client)->sock, msg, strlen(msg), 0);
}

void handler_fun_type(client * this_client, char * args) {
	send(((client *) this_client)->sock, "200 TYPE\n", 9, 0);
}

void handler_fun_acct(client * this_client, char * args) {
	send(this_client->sock, "230 OK\n",7,0);
}

void handler_fun_syst(client * this_client, char * args) {
	send(this_client->sock, "215 UNIX Type: L8\n", 18, 0);
}

void bg_accept(client * this_client) {
	struct sockaddr tempaddr;
	socklen_t addrlen;
	struct pollfd interesting;
	interesting.fd = this_client->session.data_sock;
	interesting.events = POLLIN;
	int oldport = this_client->session.data_sock;
	if (poll(&interesting, (nfds_t) 1, 5000)>0) {
		this_client->session.data_sock = accept(this_client->session.data_sock, &tempaddr, &addrlen);
		close(oldport);
	} else {
		close(this_client->session.data_sock);
		this_client->session.data_sock = -1;
	}
//	this_client->session.data_sock = accept(this_client->session.data_sock, &tempaddr, &addrlen);
//	close(oldport);
}

char * parse_local_addr(){
	char parsed[16], *p;
	struct sockaddr_in * addr = (struct sockaddr_in *) local_addr("");
	strncpy(parsed, inet_ntoa(addr->sin_addr), 16);
	for (p=parsed; *p; p++){
		if (*p == '.'){
			*p = ',';
		}
	}
	strncpy(pasv_addr, parsed, 16);
	return pasv_addr;
}

void handler_fun_pasv(client * this_client, char * args) {
	char buf[64];
	memset(buf, 0, 64);
	int port;
	int clientsock;
	int oldport = this_client->session.data_sock;
	struct sockaddr tempaddr;
	pthread_t current_thread;
	socklen_t addrlen;
	clientsock = create_data_sock(this_client);
	port = (int) this_client->session.data_addr.sin_port;
	sprintf(buf, "227 Entering Passive Mode (%s,%d,%d)\n", parse_local_addr(), port%256, port/256);
	LOG("Socket is on port %d\n", port);
	pthread_create(&current_thread, NULL, bg_accept, this_client);
	send(this_client->sock, buf, strlen(buf),0);
	pthread_join(current_thread, NULL);
	if (this_client->session.data_sock == -1) {
		send(this_client->sock, "426 Broken\n", 11, 0);
	} else {
//		send(this_client->sock, "150 Accepted\n", 13, 0);
	}
}

void handler_fun_list(client * this_client, char * args) {
	int status;
	if (this_client->session.data_sock == -1){
		send(this_client->sock, "425 No socket\n", 14, 0);
	} else {
		if (fork() == 0) {
			send(this_client->sock, "150 Read\n", 9, 0);
			LOG("Sending content of %s", args);
			dup2(this_client->session.data_sock, 1);
			dup2(this_client->session.data_sock, 2);
			if (args[0]) {
				execl("/bin/ls", "ls", "-l", args, NULL);
			} else {
				execl("/bin/ls", "ls", "-l", this_client->session.pwd, NULL);
			}
		} else {
			wait(&status);
			close(this_client->session.data_sock);
			this_client->session.data_sock = -1;
			send(this_client->sock, "226 Sent\n", 9, 0);
			LOG("Listing sent\n");
		}
	}
}

void handler_fun_quit(client * this_client, char * args) {
	send(this_client->sock, "221 Tsau\n", 9, 0);
	close(this_client->sock);
}

void handler_fun_cwd(client * this_client, char * args) {
	char * cp;
	char * delim;
	char oldpath[512];
	strncpy(oldpath, this_client->session.pwd, 511);
	if (strncmp("..", args, 2) == 0) {
		for (cp = this_client->session.pwd; *(cp+2); cp++){
			if (*cp == '/')
				delim = cp;
		}
		delim[1] = 0;
		send(this_client->sock, "250 OK\n", 7, 0);
	} else {
		if (args[0] == '/') {
			strncpy(this_client->session.pwd, args, 254);
		} else {
			strncat(this_client->session.pwd, args, 254);
		}
		for (cp = this_client->session.pwd; *(cp+1); cp++);
		if (*cp != '/') {
			cp++;
			*cp = '/';
		}
		if (access(this_client->session.pwd, F_OK|R_OK)) {
			strncpy(this_client->session.pwd, oldpath, 511);
			send(this_client->sock, "550 NA\n", 7, 0);
		} else {
			send(this_client->sock, "250 OK\n", 7, 0);
		}
	}
}

void handler_fun_retr(client * this_client, char * args) {
	FILE * stream;
	char buf[8064];
	int read;
	char path[512];
	if (args[0] == '/') {
		strncpy(path, args, 511);
	} else {
		strncpy(path, this_client->session.pwd, 256);
		strncat(path, args, 255);
	}
	if (this_client->session.data_sock == -1) {
		send(this_client->sock, "426 Broken\n", 11, 0);
	} else {
		if ((stream = fopen(path, "r")) != NULL) {
			send(this_client->sock, "150 Read\n", 9, 0);
			while ((read = fread(buf, sizeof(char), 8064, stream)) > 0) {
				send(this_client->session.data_sock, buf, read, 0);
				memset(buf, 0, 8064);
			}
			close(this_client->session.data_sock);
			this_client->session.data_sock = -1;
			if (ferror(stream)) {
				send(this_client->sock, "451 Read error\n", 15, 0);
			} else {
				send(this_client->sock, "226 Read ok\n", 12, 0);
			}
			fclose(stream);
		} else {
			close(this_client->session.data_sock);
			send(this_client->sock, "550 Read error\n", 15, 0);
		}
	}
}

void handler_fun_stor(client * this_client, char * args) {
	FILE * stream;
	char buf[8064];
	int read;
	char path[512];
	if (args[0] == '/'){
		strncpy(path,args,511);
	} else {
		strncpy(path, this_client->session.pwd, 256);
		strncat(path, args, 255);
	}
	if (this_client->session.data_sock == -1) {
		send(this_client->sock, "450 Broken\n", 11, 0);
	} else {
		if ((stream = fopen(path, "w")) != NULL) {
			send(this_client->sock, "150 Send\n", 9, 0);
			while ((read = recv(this_client->session.data_sock, buf, 8064, 0)) > 0) {
				fwrite(buf, sizeof(char), read, stream);
			}
			close(this_client->session.data_sock);
			this_client->session.data_sock = -1;
			if (ferror(stream)) {
				send(this_client->sock, "451 Write error\n", 16, 0);
			} else {
				send(this_client->sock, "226 Write ok\n", 13, 0);
			}
			fclose(stream);
		} else {
			send(this_client->sock, "450 Stream open error\n", 22, 0);
		}
	}
}

void handler_fun_cdup(client * this_client, char * args) {
	handler_fun_cwd(this_client, "..");
}

void build_handler(void (*fun)(client *, char *), char * CMD) {
	handler_entry_t * handler_name = malloc(sizeof(handler_entry_t));
	handler_entry_t * hp;
	if (handlers == NULL){
		handlers = handler_name;
	} else {
		for (hp = handlers; hp->next != NULL; hp = hp->next);
		hp->next = handler_name;
	}
	strcpy(handler_name->cmd, CMD);
	handler_name->fun = fun;
	handler_name->next = NULL;
	LOG("Built %s handler\n", CMD);
}



void build_handlers() {
	build_handler(handler_fun_user, "USER");
	build_handler(handler_fun_pass, "PASS");
	build_handler(handler_fun_pwd, "PWD");
	build_handler(handler_fun_type, "TYPE");
	build_handler(handler_fun_acct, "ACCT");
	build_handler(handler_fun_syst, "SYST");
	build_handler(handler_fun_pasv, "PASV");
	build_handler(handler_fun_list, "LIST");
	build_handler(handler_fun_quit, "QUIT");
	build_handler(handler_fun_cwd, "CWD");
	build_handler(handler_fun_retr, "RETR");
	build_handler(handler_fun_stor, "STOR");
	build_handler(handler_fun_cdup, "CDUP");
}