server.cpp

c++编写的FTP服务器和客户端程序

#include <fstream>
#include <sstream>
#include <unistd.h>
#include "server.h"
using namespace std;

const string Server::FTP_ROOT = ".";
TcpFactory* Server::listenTcp = new Tcpfactory;
map<string, string> Server::users;

Server::Server(Tcp* ctrl) {
	pi = ctrl;
	logon = false;
	passive = false;
	dataType = Tcp::ASCII;
}

Server::~Server() {
	delete pi;
	delete data;
}

Server* Server::listen(int port) {
	listenTcp->setLocalPort(port);
	return new Server(listenTcp->listen());
}

void Server::addUser(const string& username, const string& password) {
	users.insert(make_pair(username, password));
}

void Server::start() {
	delete listenTcp;
	pi->write("220 FTP Server ready.");

	while(true) {
		string command = pi->read();

		try {
			if(command.substr(0, 5)=="USER ") {
				map<string, string>::iterator user = users.find(command.substr(5));
				if(user==users.end()) {
					pi->write("530 Not logged in.");
					logon = false;
					continue;
				}

				if(user->second.length()) {
					pi->write("331 User name okay, need password.");
					if(pi->read()!="PASS "+user->second) {
						pi->write("530 Not logged in.");
						logon = false;
						continue;
					}
				}

				pi->write("230 User logged in, proceed.");
				logon = true;

			} else if(command.substr(0, 4)=="CWD ") {
				if(checkPermission())
					if(access(dir.buildFullname(FTP_ROOT, command.substr(4)).c_str(), X_OK))
						pi->write("550 No such file or directory.");
					else {
						dir.cd(command.substr(4));
						pi->write("250 CWD command successful.");
					}

			} else if(command=="CDUP") {
				if(checkPermission()) {
					dir.cd("..");
					pi->write("200 CDUP command successful.");
				}

			} else if(command=="QUIT") {
				pi->write("221 Goodbye.");
				logon = false;
				return;

			} else if(command.substr(0, 5)=="PORT ") {
				if(checkPermission()) {
					int addr = 0;
					int port;
					int i = 5;
					for(int j=0; j<5; j++) {
						int comma = command.find(',', i);
						if(j<4)
							addr = (addr<<8)+atoi(command.substr(i, comma-i).c_str());
						else
							port = atoi(command.substr(i, comma-i).c_str());
						i = comma+1;
					}
					port = (port<<8)+atoi(command.substr(i).c_str());

					dtp.setDest(addr, port);
					passive = false;

					pi->write("200 PORT command successful.");
				}

			} else if(command=="PASV") {
				if(checkPermission()) {
					int addr = pi->getLocalAddr();
					int port = rand();
					stringstream ss;
					ss << "227 Entering Passive Mode (" << (addr>>24) << ',';
					ss << ((addr>>16)&0xff) << ',' << ((addr>>8)&0xff) << ',';
					ss << (addr&0xff) << ',' << ((port>>8)&0xff) << ',';
					ss << (port&0xff) << ").";
					pi->write(ss.str());

					passive = true;
					dtp.setLocalPort(port);
					data = dtp.listen();
				}

			} else if(command.substr(0, 5)=="TYPE ") {
				if(checkPermission()) {
					switch(command[5]) {
					case 'A':
						dataType = Tcp::ASCII;
						break;
					case 'I':
						dataType = Tcp::IMAGE;
						break;
					default:
						pi->write("504 Command not implemented for that parameter.");
						continue;
					}

					pi->write(string("200 Type set to ") + command[5] + ".");
				}

			} else if(command.substr(0, 5)=="STOR " || command.substr(0, 5)=="APPE ") {
				if(checkPermission()) {
					string filename = dir.buildFullname(FTP_ROOT, command.substr(5));

					ofstream os(filename.c_str(), command[0]=='S' ?
						(dataType==Tcp::ASCII ? ios::out : ios::binary) :
						(dataType==Tcp::ASCII ? ios::app : ios::app|ios::binary));
					if(!os) {
						pi->write("553 Requested action not taken.");
						continue;
					}

					pi->write(string("150 Opening ") + (dataType==Tcp::ASCII ? "ASCII" : "Binary") +
						" mode data connection for " + command.substr(5) + ".");
					openDataConnection();

					data->setDataType(dataType);
					data->readToStream(os);

					delete data;
					pi->write("226 Transfer complete.");
				}

			} else if(command.substr(0, 5)=="RETR " || command.substr(0, 4)=="LIST") {
				if(checkPermission()) {
					string filename;
					if(command[0]=='L')
						if(command.length()==4) {
							char tmp[] = "/tmp/ftpd.XXXXXX";
							mkstemp(tmp);
							filename = tmp;
							system(string("ls -l " + dir.buildFullname(FTP_ROOT, "") + " > " +
								filename).c_str());
						} else if(command.length()>5 && command[4]==' ') {
							char tmp[] = "/tmp/ftpd.XXXXXX";
							mkstemp(tmp);
							filename = tmp;
							system(string("ls -l " + dir.buildFullname(FTP_ROOT, command[5]=='-' ?
								" "+command.substr(5) : command.substr(5)) + " > " + filename).c_str());
						} else {
							pi->write("502 Command not implemented.");
							continue;
						}
					else
						filename = dir.buildFullname(FTP_ROOT, command.substr(5));

					ifstream is(filename.c_str(), dataType==Tcp::ASCII?ios::in:ios::binary);
					if(!is) {
						pi->write("550 No such file or directory.");
						continue;
					}

					pi->write(string("150 Opening ") + (dataType==Tcp::ASCII ? "ASCII" : "Binary") +
						" mode data connection for " + (command[0]=='L' ? "file list" :
						command.substr(5)) + ".");
					openDataConnection();

					if(command[0]!='L') data->setDataType(dataType);
					data->writeFromStream(is);

					delete data;
					pi->write("226 Transfer complete.");

					if(command[0]=='L') remove(filename.c_str());
				}

			} else if(command=="PWD") {
				pi->write("257 \"" + string(dir) + "\" is current directory.");

			} else if(command=="ABOR") {
				pi->write("226 Closing data connection.");

			} else if(command=="SYST") {
				pi->write("215 UNIX Type: L8");

			} else if(command.substr(0, 4)=="HELP") {
				if(command.length()==4) {
					pi->write("214-The following commands are recognized:");
					pi->write(" CWD     CDUP    QUIT    PORT    PASV    PWD     SYST    HELP");
					pi->write(" NOOP    TYPE    MODE    RETR    STOR    APPE    ABOR    USER");
					pi->write(" PASS    LIST");
					pi->write("214 FTP daemon implemented by Meng Xiangliang");
				} else if(command.length()>5 && command[4]==' ')
					pi->write("214 Help message.");
				else
					pi->write("502 Command not implemented.");

			} else if(command.substr(0, 5)=="MODE ") {
				pi->write("504 Command not implemented for that parameter.");

			} else if(command=="NOOP") {
				pi->write("200 Command okay.");

			} else
				pi->write("502 Command not implemented.");

		} catch(const char* message) {
			cerr << "ERROR: " << message << endl;
		}
	}
}

bool Server::checkPermission() {
	if(logon)
		return true;
	else {
		pi->write("530 Not logged in.");
		return false;
	}
}

void Server::openDataConnection() {
	if(passive)
		passive = false;
	else
		data = dtp.connect();
}

int main(int argc, char* argv[]) {
	Server::addUser("anonymous", "");
	Server::addUser("mxl", "mxl");

	while(true) {
		Server* server = Server::listen(argc>1 ? atoi(argv[1]) : 2382);
		if(fork()>0) {
			server->start();
			delete server;
			return 0;
		} else
			delete server;
	}
}