ftpd.c

早期freebsd实现

	(void) initgroups(pw->pw_name, pw->pw_gid);

	/* open wtmp before chroot */
	(void)sprintf(ttyline, "ftp%d", getpid());
	logwtmp(ttyline, pw->pw_name, remotehost);
	logged_in = 1;

	if (guest) {
		/*
		 * We MUST do a chdir() after the chroot. Otherwise
		 * the old current directory will be accessible as "."
		 * outside the new root!
		 */
		if (chroot(pw->pw_dir) < 0 || chdir("/") < 0) {
			reply(550, "Can't set guest privileges.");
			goto bad;
		}
	} else if (chdir(pw->pw_dir) < 0) {
		if (chdir("/") < 0) {
			reply(530, "User %s: can't change directory to %s.",
			    pw->pw_name, pw->pw_dir);
			goto bad;
		} else
			lreply(230, "No directory! Logging in with home=/");
	}
	if (seteuid((uid_t)pw->pw_uid) < 0) {
		reply(550, "Can't set uid.");
		goto bad;
	}
	/*
	 * Display a login message, if it exists.
	 * N.B. reply(230,) must follow the message.
	 */
	if ((fd = fopen(_PATH_FTPLOGINMESG, "r")) != NULL) {
		char *cp, line[LINE_MAX];

		while (fgets(line, sizeof(line), fd) != NULL) {
			if ((cp = strchr(line, '\n')) != NULL)
				*cp = '\0';
			lreply(230, "%s", line);
		}
		(void) fflush(stdout);
		(void) fclose(fd);
	}
	if (guest) {
		reply(230, "Guest login ok, access restrictions apply.");
#ifdef SETPROCTITLE
		snprintf(proctitle, sizeof(proctitle),
		    "%s: anonymous/%.*s", remotehost,
		    sizeof(proctitle) - sizeof(remotehost) -
		    sizeof(": anonymous/"), passwd);
		setproctitle(proctitle);
#endif /* SETPROCTITLE */
		if (logging)
			syslog(LOG_INFO, "ANONYMOUS FTP LOGIN FROM %s, %s",
			    remotehost, passwd);
	} else {
		reply(230, "User %s logged in.", pw->pw_name);
#ifdef SETPROCTITLE
		snprintf(proctitle, sizeof(proctitle),
		    "%s: %s", remotehost, pw->pw_name);
		setproctitle(proctitle);
#endif /* SETPROCTITLE */
		if (logging)
			syslog(LOG_INFO, "FTP LOGIN FROM %s as %s",
			    remotehost, pw->pw_name);
	}
	(void) umask(defumask);
	return;
bad:
	/* Forget all about it... */
	end_login();
}

void
retrieve(cmd, name)
	char *cmd, *name;
{
	FILE *fin, *dout;
	struct stat st;
	int (*closefunc) __P((FILE *));

	if (cmd == 0) {
		fin = fopen(name, "r"), closefunc = fclose;
		st.st_size = 0;
	} else {
		char line[BUFSIZ];

		(void) sprintf(line, cmd, name), name = line;
		fin = ftpd_popen(line, "r"), closefunc = ftpd_pclose;
		st.st_size = -1;
		st.st_blksize = BUFSIZ;
	}
	if (fin == NULL) {
		if (errno != 0) {
			perror_reply(550, name);
			if (cmd == 0) {
				LOGCMD("get", name);
			}
		}
		return;
	}
	byte_count = -1;
	if (cmd == 0 && (fstat(fileno(fin), &st) < 0 || !S_ISREG(st.st_mode))) {
		reply(550, "%s: not a plain file.", name);
		goto done;
	}
	if (restart_point) {
		if (type == TYPE_A) {
			off_t i, n;
			int c;

			n = restart_point;
			i = 0;
			while (i++ < n) {
				if ((c=getc(fin)) == EOF) {
					perror_reply(550, name);
					goto done;
				}
				if (c == '\n')
					i++;
			}
		} else if (lseek(fileno(fin), restart_point, L_SET) < 0) {
			perror_reply(550, name);
			goto done;
		}
	}
	dout = dataconn(name, st.st_size, "w");
	if (dout == NULL)
		goto done;
	send_data(fin, dout, st.st_blksize);
	(void) fclose(dout);
	data = -1;
	pdata = -1;
done:
	if (cmd == 0)
		LOGBYTES("get", name, byte_count);
	(*closefunc)(fin);
}

void
store(name, mode, unique)
	char *name, *mode;
	int unique;
{
	FILE *fout, *din;
	struct stat st;
	int (*closefunc) __P((FILE *));

	if (unique && stat(name, &st) == 0 &&
	    (name = gunique(name)) == NULL) {
		LOGCMD(*mode == 'w' ? "put" : "append", name);
		return;
	}

	if (restart_point)
		mode = "r+";
	fout = fopen(name, mode);
	closefunc = fclose;
	if (fout == NULL) {
		perror_reply(553, name);
		LOGCMD(*mode == 'w' ? "put" : "append", name);
		return;
	}
	byte_count = -1;
	if (restart_point) {
		if (type == TYPE_A) {
			off_t i, n;
			int c;

			n = restart_point;
			i = 0;
			while (i++ < n) {
				if ((c=getc(fout)) == EOF) {
					perror_reply(550, name);
					goto done;
				}
				if (c == '\n')
					i++;
			}
			/*
			 * We must do this seek to "current" position
			 * because we are changing from reading to
			 * writing.
			 */
			if (fseek(fout, 0L, L_INCR) < 0) {
				perror_reply(550, name);
				goto done;
			}
		} else if (lseek(fileno(fout), restart_point, L_SET) < 0) {
			perror_reply(550, name);
			goto done;
		}
	}
	din = dataconn(name, (off_t)-1, "r");
	if (din == NULL)
		goto done;
	if (receive_data(din, fout) == 0) {
		if (unique)
			reply(226, "Transfer complete (unique file name:%s).",
			    name);
		else
			reply(226, "Transfer complete.");
	}
	(void) fclose(din);
	data = -1;
	pdata = -1;
done:
	LOGBYTES(*mode == 'w' ? "put" : "append", name, byte_count);
	(*closefunc)(fout);
}

static FILE *
getdatasock(mode)
	char *mode;
{
	int on = 1, s, t, tries;

	if (data >= 0)
		return (fdopen(data, mode));
	(void) seteuid((uid_t)0);
	s = socket(AF_INET, SOCK_STREAM, 0);
	if (s < 0)
		goto bad;
	if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR,
	    (char *) &on, sizeof(on)) < 0)
		goto bad;
	/* anchor socket to avoid multi-homing problems */
	data_source.sin_family = AF_INET;
	data_source.sin_addr = ctrl_addr.sin_addr;
	for (tries = 1; ; tries++) {
		if (bind(s, (struct sockaddr *)&data_source,
		    sizeof(data_source)) >= 0)
			break;
		if (errno != EADDRINUSE || tries > 10)
			goto bad;
		sleep(tries);
	}
	(void) seteuid((uid_t)pw->pw_uid);
#ifdef IP_TOS
	on = IPTOS_THROUGHPUT;
	if (setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&on, sizeof(int)) < 0)
		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
#endif
	return (fdopen(s, mode));
bad:
	/* Return the real value of errno (close may change it) */
	t = errno;
	(void) seteuid((uid_t)pw->pw_uid);
	(void) close(s);
	errno = t;
	return (NULL);
}

static FILE *
dataconn(name, size, mode)
	char *name;
	off_t size;
	char *mode;
{
	char sizebuf[32];
	FILE *file;
	int retry = 0, tos;

	file_size = size;
	byte_count = 0;
	if (size != (off_t) -1)
		(void) sprintf(sizebuf, " (%qd bytes)", size);
	else
		(void) strcpy(sizebuf, "");
	if (pdata >= 0) {
		struct sockaddr_in from;
		int s, fromlen = sizeof(from);

		s = accept(pdata, (struct sockaddr *)&from, &fromlen);
		if (s < 0) {
			reply(425, "Can't open data connection.");
			(void) close(pdata);
			pdata = -1;
			return (NULL);
		}
		(void) close(pdata);
		pdata = s;
#ifdef IP_TOS
		tos = IPTOS_LOWDELAY;
		(void) setsockopt(s, IPPROTO_IP, IP_TOS, (char *)&tos,
		    sizeof(int));
#endif
		reply(150, "Opening %s mode data connection for '%s'%s.",
		     type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
		return (fdopen(pdata, mode));
	}
	if (data >= 0) {
		reply(125, "Using existing data connection for '%s'%s.",
		    name, sizebuf);
		usedefault = 1;
		return (fdopen(data, mode));
	}
	if (usedefault)
		data_dest = his_addr;
	usedefault = 1;
	file = getdatasock(mode);
	if (file == NULL) {
		reply(425, "Can't create data socket (%s,%d): %s.",
		    inet_ntoa(data_source.sin_addr),
		    ntohs(data_source.sin_port), strerror(errno));
		return (NULL);
	}
	data = fileno(file);
	while (connect(data, (struct sockaddr *)&data_dest,
	    sizeof(data_dest)) < 0) {
		if (errno == EADDRINUSE && retry < swaitmax) {
			sleep((unsigned) swaitint);
			retry += swaitint;
			continue;
		}
		perror_reply(425, "Can't build data connection");
		(void) fclose(file);
		data = -1;
		return (NULL);
	}
	reply(150, "Opening %s mode data connection for '%s'%s.",
	     type == TYPE_A ? "ASCII" : "BINARY", name, sizebuf);
	return (file);
}

/*
 * Tranfer the contents of "instr" to "outstr" peer using the appropriate
 * encapsulation of the data subject * to Mode, Structure, and Type.
 *
 * NB: Form isn't handled.
 */
static void
send_data(instr, outstr, blksize)
	FILE *instr, *outstr;
	off_t blksize;
{
	int c, cnt, filefd, netfd;
	char *buf;

	transflag++;
	if (setjmp(urgcatch)) {
		transflag = 0;
		return;
	}
	switch (type) {

	case TYPE_A:
		while ((c = getc(instr)) != EOF) {
			byte_count++;
			if (c == '\n') {
				if (ferror(outstr))
					goto data_err;
				(void) putc('\r', outstr);
			}
			(void) putc(c, outstr);
		}
		fflush(outstr);
		transflag = 0;
		if (ferror(instr))
			goto file_err;
		if (ferror(outstr))
			goto data_err;
		reply(226, "Transfer complete.");
		return;

	case TYPE_I:
	case TYPE_L:
		if ((buf = malloc((u_int)blksize)) == NULL) {
			transflag = 0;
			perror_reply(451, "Local resource failure: malloc");
			return;
		}
		netfd = fileno(outstr);
		filefd = fileno(instr);
		while ((cnt = read(filefd, buf, (u_int)blksize)) > 0 &&
		    write(netfd, buf, cnt) == cnt)
			byte_count += cnt;
		transflag = 0;
		(void)free(buf);
		if (cnt != 0) {
			if (cnt < 0)
				goto file_err;
			goto data_err;
		}
		reply(226, "Transfer complete.");
		return;
	default:
		transflag = 0;
		reply(550, "Unimplemented TYPE %d in send_data", type);
		return;
	}

data_err:
	transflag = 0;
	perror_reply(426, "Data connection");
	return;

file_err:
	transflag = 0;
	perror_reply(551, "Error on input file");
}

/*
 * Transfer data from peer to "outstr" using the appropriate encapulation of
 * the data subject to Mode, Structure, and Type.
 *
 * N.B.: Form isn't handled.
 */
static int
receive_data(instr, outstr)
	FILE *instr, *outstr;
{
	int c;
	int cnt, bare_lfs = 0;
	char buf[BUFSIZ];

	transflag++;
	if (setjmp(urgcatch)) {
		transflag = 0;
		return (-1);
	}
	switch (type) {

	case TYPE_I:
	case TYPE_L:
		while ((cnt = read(fileno(instr), buf, sizeof(buf))) > 0) {
			if (write(fileno(outstr), buf, cnt) != cnt)
				goto file_err;
			byte_count += cnt;
		}
		if (cnt < 0)
			goto data_err;
		transflag = 0;
		return (0);

	case TYPE_E:
		reply(553, "TYPE E not implemented.");
		transflag = 0;
		return (-1);

	case TYPE_A:
		while ((c = getc(instr)) != EOF) {
			byte_count++;
			if (c == '\n')
				bare_lfs++;
			while (c == '\r') {
				if (ferror(outstr))
					goto data_err;
				if ((c = getc(instr)) != '\n') {
					(void) putc ('\r', outstr);
					if (c == '\0' || c == EOF)
						goto contin2;
				}
			}
			(void) putc(c, outstr);
	contin2:	;
		}
		fflush(outstr);
		if (ferror(instr))
			goto data_err;
		if (ferror(outstr))
			goto file_err;
		transflag = 0;
		if (bare_lfs) {
			lreply(226,
		"WARNING! %d bare linefeeds received in ASCII mode",
			    bare_lfs);
		(void)printf("   File may not have transferred correctly.\r\n");
		}
		return (0);
	default:
		reply(550, "Unimplemented TYPE %d in receive_data", type);
		transflag = 0;
		return (-1);
	}

data_err:
	transflag = 0;
	perror_reply(426, "Data Connection");
	return (-1);

file_err:
	transflag = 0;
	perror_reply(452, "Error writing file");
	return (-1);
}

void
statfilecmd(filename)
	char *filename;
{
	FILE *fin;
	int c;
	char line[LINE_MAX];

	(void)snprintf(line, sizeof(line), "/bin/ls -lgA %s", filename);
	fin = ftpd_popen(line, "r");
	lreply(211, "status of %s:", filename);
	while ((c = getc(fin)) != EOF) {
		if (c == '\n') {
			if (ferror(stdout)){
				perror_reply(421, "control connection");
				(void) ftpd_pclose(fin);
				dologout(1);
				/* NOTREACHED */
			}
			if (ferror(fin)) {
				perror_reply(551, filename);
				(void) ftpd_pclose(fin);
				return;
			}
			(void) putc('\r', stdout);
		}
		(void) putc(c, stdout);
	}
	(void) ftpd_pclose(fin);
	reply(211, "End of Status");
}

void
statcmd()
{
	struct sockaddr_in *sin;
	u_char *a, *p;

	lreply(211, "%s FTP server status:", hostname, version);
	printf("     %s\r\n", version);
	printf("     Connected to %s", remotehost);
	if (!isdigit(remotehost[0]))
		printf(" (%s)", inet_ntoa(his_addr.sin_addr));
	printf("\r\n");
	if (logged_in) {
		if (guest)
			printf("     Logged in anonymously\r\n");
		else
			printf("     Logged in as %s\r\n", pw->pw_name);
	} else if (askpasswd)
		printf("     Waiting for password\r\n");
	else
		printf("     Waiting for user name\r\n");
	printf("     TYPE: %s", typenames[type]);
	if (type == TYPE_A || type == TYPE_E)
		printf(", FORM: %s", formnames[form]);
	if (type == TYPE_L)
#if NBBY == 8
		printf(" %d", NBBY);
#else
		printf(" %d", bytesize);	/* need definition! */
#endif
	printf("; STRUcture: %s; transfer MODE: %s\r\n",
	    strunames[stru], modenames[mode]);