ftpd.c

伯克利大学的一个ftp协议的实现源代码,包括客户端和服务器端.

}

/* ARGSUSED */
void
yyerror(char *s)
{
	char *cp;
        
	(void)s; /* ignore argument */

	if ((cp = strchr(cbuf,'\n'))!=NULL)
		*cp = '\0';
	reply(500, "'%s': command not understood.", cbuf);
}

void
delete(name)
	char *name;
{
	struct stat st;

	LOGCMD("delete", name);
	if (stat(name, &st) < 0) {
		perror_reply(550, name);
		return;
	}
	if ((st.st_mode&S_IFMT) == S_IFDIR) {
		if (rmdir(name) < 0) {
			perror_reply(550, name);
			return;
		}
		goto done;
	}
	if (unlink(name) < 0) {
		perror_reply(550, name);
		return;
	}
done:
	ack("DELE");
}

void
cwd(path)
	const char *path;
{
	FILE *message;

	if (chdir(path) < 0)
		perror_reply(550, path);
	else {
		if ((message = fopen(_PATH_CWDMESG, "r")) != NULL) {
			char *cp, line[LINE_MAX];

			while (fgets(line, sizeof(line), message) != NULL) {
				if ((cp = strchr(line, '\n')) != NULL)
					*cp = '\0';
				lreply(250, "%s", line);
			}
			(void) fflush(stdout);
			(void) fclose(message);
		}
		ack("CWD");
	}
}

void
makedir(name)
	char *name;
{

	LOGCMD("mkdir", name);
	if (mkdir(name, 0777) < 0)
		perror_reply(550, name);
	else
		reply(257, "MKD command successful.");
}

void
removedir(name)
	char *name;
{

	LOGCMD("rmdir", name);
	if (rmdir(name) < 0)
		perror_reply(550, name);
	else
		ack("RMD");
}

void
pwd()
{
	char path[MAXPATHLEN + 1];

	if (getwd(path) == (char *)NULL)
		reply(550, "%s.", path);
	else
		reply(257, "\"%s\" is current directory.", path);
}

char *
renamefrom(name)
	char *name;
{
	struct stat st;

	if (stat(name, &st) < 0) {
		perror_reply(550, name);
		return ((char *)0);
	}
	reply(350, "File exists, ready for destination name");
	return (name);
}

void
renamecmd(from, to)
	char *from, *to;
{

	LOGCMD2("rename", from, to);
	if (rename(from, to) < 0)
		perror_reply(550, "rename");
	else
		ack("RNTO");
}

static void
dolog(sn)
	struct sockaddr_in *sn;
{
	struct hostent *hp = gethostbyaddr((char *)&sn->sin_addr,
		sizeof(struct in_addr), AF_INET);

	if (hp)
		(void) strncpy(remotehost, hp->h_name, sizeof(remotehost)-1);
	else
		(void) strncpy(remotehost, inet_ntoa(sn->sin_addr),
		    sizeof(remotehost)-1);
	remotehost[sizeof(remotehost)-1] = '\0';
#ifdef HASSETPROCTITLE
	snprintf(proctitle, sizeof(proctitle), "%s: connected", remotehost);
	setproctitle(proctitle);
#endif /* HASSETPROCTITLE */

	if (logging)
		syslog(LOG_INFO, "connection from %s", remotehost);
}

/*
 * Record logout in wtmp file
 * and exit with supplied status.
 */
void
dologout(status)
	int status;
{
	sigset_t allsigs;

	transflag = 0;

	if (logged_in) {
		sigfillset(&allsigs);
		sigprocmask(SIG_BLOCK, &allsigs, NULL);
		(void) seteuid((uid_t)0);
		logwtmp(ttyline, "", "");
		if (doutmp)
			logout(utmp.ut_line);
#if defined(KERBEROS)
		if (!notickets && krbtkfile_env)
			unlink(krbtkfile_env);
#endif
	}
	/* beware of flushing buffers after a SIGPIPE */
	_exit(status);
}

static void
myoob(int signo)
{
	char *cp;

	(void)signo;

	/* only process if transfer occurring */
	if (!transflag)
		return;
	cp = tmpline;
	if (getline(cp, 7, stdin) == NULL) {
		reply(221, "You could at least say goodbye.");
		dologout(0);
	}
	upper(cp);
	if (strcmp(cp, "ABOR\r\n") == 0) {
		tmpline[0] = '\0';
		reply(426, "Transfer aborted. Data connection closed.");
		reply(226, "Abort successful");
		longjmp(urgcatch, 1);
	}
	if (strcmp(cp, "STAT\r\n") == 0) {
		if (file_size != (off_t) -1)
			reply(213, "Status: %qd of %qd bytes transferred",
			    (quad_t) byte_count, (quad_t) file_size);
		else
			reply(213, "Status: %qd bytes transferred", 
			    (quad_t)byte_count);
	}
}

/*
 * Note: a response of 425 is not mentioned as a possible response to
 *	the PASV command in RFC959. However, it has been blessed as
 *	a legitimate response by Jon Postel in a telephone conversation
 *	with Rick Adams on 25 Jan 89.
 */
void
passive()
{
	int len;
#ifdef IP_PORTRANGE
	int on;
#else
	u_short port;
#endif

	char *p, *a;

	if (pw == NULL) {
		reply(530, "Please login with USER and PASS");
		return;
	}
	if (pdata >= 0)
		close(pdata);
	pdata = socket(AF_INET, SOCK_STREAM, 0);
	if (pdata < 0) {
		perror_reply(425, "Can't open passive connection");
		return;
	}

#ifdef IP_PORTRANGE
	on = high_data_ports ? IP_PORTRANGE_HIGH : IP_PORTRANGE_DEFAULT;
	if (setsockopt(pdata, IPPROTO_IP, IP_PORTRANGE,
		       (char *)&on, sizeof(on)) < 0)
		goto pasv_error;
#else
#define FTP_DATA_BOTTOM 40000
#define FTP_DATA_TOP    44999
	if (high_data_ports) {
		for (port = FTP_DATA_BOTTOM; port <= FTP_DATA_TOP; port++) {
			pasv_addr = ctrl_addr;
			pasv_addr.sin_port = htons(port);
			if (bind(pdata, (struct sockaddr *) &pasv_addr,
				 sizeof(pasv_addr)) == 0)
				break;
			if (errno != EADDRINUSE)
				goto pasv_error;
		}
		if (port > FTP_DATA_TOP)
			goto pasv_error;
	}
	else
#endif
	{
		pasv_addr = ctrl_addr;
		pasv_addr.sin_port = 0;
		if (bind(pdata, (struct sockaddr *)&pasv_addr,
			 sizeof(pasv_addr)) < 0)
			goto pasv_error;
	}

	len = sizeof(pasv_addr);
	if (getsockname(pdata, (struct sockaddr *) &pasv_addr, &len) < 0)
		goto pasv_error;
	if (listen(pdata, 1) < 0)
		goto pasv_error;
	a = (char *) &pasv_addr.sin_addr;
	p = (char *) &pasv_addr.sin_port;

#define UC(b) (((int) b) & 0xff)

	reply(227, "Entering Passive Mode (%d,%d,%d,%d,%d,%d)", UC(a[0]),
		UC(a[1]), UC(a[2]), UC(a[3]), UC(p[0]), UC(p[1]));
	return;

pasv_error:
	(void) close(pdata);
	pdata = -1;
	perror_reply(425, "Can't open passive connection");
	return;
}

/*
 * Generate unique name for file with basename "local".
 * The file named "local" is already known to exist.
 * Generates failure reply on error.
 */
static int
guniquefd(local, nam)
	const char *local;
	char **nam;
{
	static char new[MAXPATHLEN];
	struct stat st;
	int count, len, fd;
	char *cp;

	cp = strrchr(local, '/');
	if (cp)
		*cp = '\0';
	if (stat(cp ? local : ".", &st) < 0) {
		perror_reply(553, cp ? local : ".");
		return (-1);
	}
	if (cp)
		*cp = '/';
	(void) strncpy(new, local, sizeof(new)-1);
	new[sizeof(new)-1] = '\0';
	len = strlen(new);
	if (len+2+1 >= (int)sizeof(new)-1)
		return (-1);
	cp = new + len;
	*cp++ = '.';
	for (count = 1; count < 100; count++) {
		(void)snprintf(cp, sizeof(new) - (cp - new), "%d", count);
		fd = open(new, O_RDWR|O_CREAT|O_EXCL, 0666);
		if (fd == -1)
			continue;
		if (nam)
			*nam = new;
		return (fd);
	}
	reply(452, "Unique file name cannot be created.");
	return (-1);
}

/*
 * Format and send reply containing system error number.
 */
void
perror_reply(code, string)
	int code;
	const char *string;
{

	reply(code, "%s: %s.", string, strerror(errno));
}

static const char *onefile[] = {
	"",
	0
};

void
send_file_list(whichf)
	const char *whichf;
{
	struct stat st;
	DIR *dirp = NULL;
	struct dirent *dir;
	FILE *volatile dout = NULL;
	char const *const *volatile dirlist;
	const char *dirname;
	volatile int simple = 0;
	volatile int freeglob = 0;
	glob_t gl;

	/* XXX: should the { go away if __linux__? */
	if (strpbrk(whichf, "~{[*?") != NULL) {
#ifdef __linux__
	        /* see popen.c */
		int flags = GLOB_NOCHECK;
#else
		int flags = GLOB_BRACE|GLOB_NOCHECK|GLOB_QUOTE|GLOB_TILDE;
#endif

		memset(&gl, 0, sizeof(gl));
		freeglob = 1;
		if (glob(whichf, flags, 0, &gl)) {
			reply(550, "not found");
			goto out;
		} else if (gl.gl_pathc == 0) {
			errno = ENOENT;
			perror_reply(550, whichf);
			goto out;
		}
		/* The cast is necessary because of bugs in C's type system */
		dirlist = (char const *const *) gl.gl_pathv;
	} else {
		onefile[0] = whichf;
		dirlist = onefile;
		simple = 1;
	}

	if (setjmp(urgcatch)) {
		transflag = 0;
		goto out;
	}
	while ((dirname = *dirlist++)!=NULL) {
		if (stat(dirname, &st) < 0) {
			/*
			 * If user typed "ls -l", etc, and the client
			 * used NLST, do what the user meant.
			 */
			if (dirname[0] == '-' && *dirlist == NULL &&
			    transflag == 0) {
				retrieve("/bin/ls %s", dirname);
				goto out;
			}
			perror_reply(550, whichf);
			if (dout != NULL) {
				(void) fclose(dout);
				transflag = 0;
				data = -1;
				pdata = -1;
			}
			goto out;
		}

		if (S_ISREG(st.st_mode)) {
			if (dout == NULL) {
				dout = dataconn("file list", (off_t)-1, "w");
				if (dout == NULL)
					goto out;
				transflag++;
			}
			fprintf(dout, "%s%s\n", dirname,
				type == TYPE_A ? "\r" : "");
			byte_count += strlen(dirname) + 1;
			continue;
		} else if (!S_ISDIR(st.st_mode))
			continue;

		if ((dirp = opendir(dirname)) == NULL)
			continue;

		while ((dir = readdir(dirp)) != NULL) {
			char nbuf[MAXPATHLEN];

#ifdef __linux__
			if (!strcmp(dir->d_name, "."))
				continue;
			if (!strcmp(dir->d_name, ".."))
				continue;
#else
			if (dir->d_name[0] == '.' && dir->d_namlen == 1)
				continue;
			if (dir->d_name[0] == '.' && dir->d_name[1] == '.' &&
			    dir->d_namlen == 2)
				continue;
#endif

			snprintf(nbuf, sizeof(nbuf), "%s/%s", dirname,
				 dir->d_name);

			/*
			 * We have to do a stat to insure it's
			 * not a directory or special file.
			 */
			if (simple || (stat(nbuf, &st) == 0 &&
			    S_ISREG(st.st_mode))) {
				if (dout == NULL) {
					dout = dataconn("file list", (off_t)-1,
						"w");
					if (dout == NULL)
						goto out;
					transflag++;
				}
				if (nbuf[0] == '.' && nbuf[1] == '/')
					fprintf(dout, "%s%s\n", &nbuf[2],
						type == TYPE_A ? "\r" : "");
				else
					fprintf(dout, "%s%s\n", nbuf,
						type == TYPE_A ? "\r" : "");
				byte_count += strlen(nbuf) + 1;
			}
		}
		(void) closedir(dirp);
	}

	if (dout == NULL)
		reply(550, "No files found.");
	else if (ferror(dout) != 0)
		perror_reply(550, "Data connection");
	else
		reply(226, "Transfer complete.");

	transflag = 0;
	if (dout != NULL)
		(void) fclose(dout);
	data = -1;
	pdata = -1;
out:
	if (freeglob) {
		freeglob = 0;
		globfree(&gl);
	}
}

static void
reapchild(int signo)
{
	(void)signo;
	while (wait3(NULL, WNOHANG, NULL) > 0);
}

void
logxfer(name, size, start)
	const char *name;
	off_t size;
	time_t start;
{
	char buf[2048];
	char path[MAXPATHLEN];
	char vremotehost[MAXHOSTNAMELEN*4], vpath[MAXPATHLEN*4];
	char *vname, *vpw;
	time_t now;

	if ((statfd >= 0) && (getcwd(path, sizeof(path)) != NULL)) {
		time(&now);

		vname = (char *)malloc(strlen(name)*4+1);
		if (vname == NULL)
			return;
		vpw = (char *)malloc(strlen((guest) ? guestpw : pw->pw_name)*4+1);
		if (vpw == NULL) {
			free(vname);
			return;
		}

		strvis(vremotehost, remotehost, VIS_SAFE|VIS_NOSLASH);
		strvis(vpath, path, VIS_SAFE|VIS_NOSLASH);
		strvis(vname, name, VIS_SAFE|VIS_NOSLASH);
		strvis(vpw, (guest) ? guestpw : pw->pw_name, VIS_SAFE|VIS_NOSLASH);

		snprintf(buf, sizeof(buf),
			 "%.24s %d %s %qd %s/%s %c %s %c %c %s ftp %d %s %s\n",
			 ctime(&now), now - start + (now == start),
			 vremotehost, (quad_t)size, vpath, vname,
			 ((type == TYPE_A) ? 'a' : 'b'), "*" /* none yet */,
			 'o', ((guest) ? 'a' : 'r'),
			 vpw, 0 /* none yet */,
			 ((guest) ? "*" : pw->pw_name), dhostname);
		write(statfd, buf, strlen(buf));
		free(vname);
		free(vpw);
	}
}