ftp.y

含有BACKTARACKING的編譯軟體

	}
	|	C
	= {
		$$ = MODE_C;
	}
	;

pathname:	pathstring
	= {
		/*
		 * Problem: this production is used for all pathname
		 * processing, but only gives a 550 error reply.
		 * This is a valid reply in some cases but not in others.
		 */
		if (logged_in && $1 && strncmp((char *) $1, "~", 1) == 0) {
			*(char **)&($$) = *glob((char *) $1);
			if (globerr != NULL) {
				reply(550, globerr);
				$$ = NULL;
			}
			free((char *) $1);
		} else
			$$ = $1;
	}
	;

pathstring:	STRING
	;

octal_number:	NUMBER
	= {
		register int ret, dec, multby, digit;

		/*
		 * Convert a number that was read as decimal number
		 * to what it would be if it had been read as octal.
		 */
		dec = $1;
		multby = 1;
		ret = 0;
		while (dec) {
			digit = dec%10;
			if (digit > 7) {
				ret = -1;
				break;
			}
			ret += digit * multby;
			multby *= 8;
			dec /= 10;
		}
		$$ = ret;
	}
	;

check_login:	/* empty */
	= {
		if (logged_in)
			$$ = 1;
		else {
			reply(530, "Please login with USER and PASS.");
			$$ = 0;
		}
	}
	;

%%

extern jmp_buf errcatch;

#define	CMD	0	/* beginning of command */
#define	ARGS	1	/* expect miscellaneous arguments */
#define	STR1	2	/* expect SP followed by STRING */
#define	STR2	3	/* expect STRING */
#define	OSTR	4	/* optional SP then STRING */
#define	ZSTR1	5	/* SP then optional STRING */
#define	ZSTR2	6	/* optional STRING after SP */
#define	SITECMD	7	/* SITE command */
#define	NSTR	8	/* Number followed by a string */

struct tab {
	char	*name;
	short	token;
	short	state;
	short	implemented;	/* 1 if command is implemented */
	char	*help;
};

struct tab cmdtab[] = {		/* In order defined in RFC 765 */
	{ "USER", USER, STR1, 1,	"<sp> username" },
	{ "PASS", PASS, ZSTR1, 1,	"<sp> password" },
	{ "ACCT", ACCT, STR1, 0,	"(specify account)" },
	{ "SMNT", SMNT, ARGS, 0,	"(structure mount)" },
	{ "REIN", REIN, ARGS, 0,	"(reinitialize server state)" },
	{ "QUIT", QUIT, ARGS, 1,	"(terminate service)", },
	{ "PORT", PORT, ARGS, 1,	"<sp> b0, b1, b2, b3, b4" },
	{ "PASV", PASV, ARGS, 1,	"(set server in passive mode)" },
	{ "TYPE", TYPE, ARGS, 1,	"<sp> [ A | E | I | L ]" },
	{ "STRU", STRU, ARGS, 1,	"(specify file structure)" },
	{ "MODE", MODE, ARGS, 1,	"(specify transfer mode)" },
	{ "RETR", RETR, STR1, 1,	"<sp> file-name" },
	{ "STOR", STOR, STR1, 1,	"<sp> file-name" },
	{ "APPE", APPE, STR1, 1,	"<sp> file-name" },
	{ "MLFL", MLFL, OSTR, 0,	"(mail file)" },
	{ "MAIL", MAIL, OSTR, 0,	"(mail to user)" },
	{ "MSND", MSND, OSTR, 0,	"(mail send to terminal)" },
	{ "MSOM", MSOM, OSTR, 0,	"(mail send to terminal or mailbox)" },
	{ "MSAM", MSAM, OSTR, 0,	"(mail send to terminal and mailbox)" },
	{ "MRSQ", MRSQ, OSTR, 0,	"(mail recipient scheme question)" },
	{ "MRCP", MRCP, STR1, 0,	"(mail recipient)" },
	{ "ALLO", ALLO, ARGS, 1,	"allocate storage (vacuously)" },
	{ "REST", REST, ARGS, 0,	"(restart command)" },
	{ "RNFR", RNFR, STR1, 1,	"<sp> file-name" },
	{ "RNTO", RNTO, STR1, 1,	"<sp> file-name" },
	{ "ABOR", ABOR, ARGS, 1,	"(abort operation)" },
	{ "DELE", DELE, STR1, 1,	"<sp> file-name" },
	{ "CWD",  CWD,  OSTR, 1,	"[ <sp> directory-name ]" },
	{ "XCWD", CWD,	OSTR, 1,	"[ <sp> directory-name ]" },
	{ "LIST", LIST, OSTR, 1,	"[ <sp> path-name ]" },
	{ "NLST", NLST, OSTR, 1,	"[ <sp> path-name ]" },
	{ "SITE", SITE, SITECMD, 1,	"site-cmd [ <sp> arguments ]" },
	{ "SYST", SYST, ARGS, 1,	"(get type of operating system)" },
	{ "STAT", STAT, OSTR, 1,	"[ <sp> path-name ]" },
	{ "HELP", HELP, OSTR, 1,	"[ <sp> <string> ]" },
	{ "NOOP", NOOP, ARGS, 1,	"" },
	{ "MKD",  MKD,  STR1, 1,	"<sp> path-name" },
	{ "XMKD", MKD,  STR1, 1,	"<sp> path-name" },
	{ "RMD",  RMD,  STR1, 1,	"<sp> path-name" },
	{ "XRMD", RMD,  STR1, 1,	"<sp> path-name" },
	{ "PWD",  PWD,  ARGS, 1,	"(return current directory)" },
	{ "XPWD", PWD,  ARGS, 1,	"(return current directory)" },
	{ "CDUP", CDUP, ARGS, 1,	"(change to parent directory)" },
	{ "XCUP", CDUP, ARGS, 1,	"(change to parent directory)" },
	{ "STOU", STOU, STR1, 1,	"<sp> file-name" },
	{ "SIZE", SIZE, OSTR, 1,	"<sp> path-name" },
	{ "MDTM", MDTM, OSTR, 1,	"<sp> path-name" },
	{ NULL,   0,    0,    0,	0 }
};

struct tab sitetab[] = {
	{ "UMASK", UMASK, ARGS, 1,	"[ <sp> umask ]" },
	{ "IDLE", IDLE, ARGS, 1,	"[ <sp> maximum-idle-time ]" },
	{ "CHMOD", CHMOD, NSTR, 1,	"<sp> mode <sp> file-name" },
	{ "HELP", HELP, OSTR, 1,	"[ <sp> <string> ]" },
	{ NULL,   0,    0,    0,	0 }
};

struct tab *
lookup(p, cmd)
	register struct tab *p;
	char *cmd;
{

	for (; p->name != NULL; p++)
		if (strcmp(cmd, p->name) == 0)
			return (p);
	return (0);
}

#include <arpa/telnet.h>

/*
 * getline - a hacked up version of fgets to ignore TELNET escape codes.
 */
char *
getline(s, n, iop)
	char *s;
	register FILE *iop;
{
	register c;
	register char *cs;

	cs = s;
/* tmpline may contain saved command from urgent mode interruption */
	for (c = 0; tmpline[c] != '\0' && --n > 0; ++c) {
		*cs++ = tmpline[c];
		if (tmpline[c] == '\n') {
			*cs++ = '\0';
			if (debug)
				syslog(LOG_DEBUG, "command: %s", s);
			tmpline[0] = '\0';
			return(s);
		}
		if (c == 0)
			tmpline[0] = '\0';
	}
	while ((c = getc(iop)) != EOF) {
		c &= 0377;
		if (c == IAC) {
		    if ((c = getc(iop)) != EOF) {
			c &= 0377;
			switch (c) {
			case WILL:
			case WONT:
				c = getc(iop);
				printf("%c%c%c", IAC, DONT, 0377&c);
				(void) fflush(stdout);
				continue;
			case DO:
			case DONT:
				c = getc(iop);
				printf("%c%c%c", IAC, WONT, 0377&c);
				(void) fflush(stdout);
				continue;
			case IAC:
				break;
			default:
				continue;	/* ignore command */
			}
		    }
		}
		*cs++ = c;
		if (--n <= 0 || c == '\n')
			break;
	}
	if (c == EOF && cs == s)
		return (NULL);
	*cs++ = '\0';
	if (debug)
		syslog(LOG_DEBUG, "command: %s", s);
	return (s);
}

static int
toolong()
{
	time_t now;
	extern char *ctime();
	extern time_t time();

	reply(421,
	  "Timeout (%d seconds): closing control connection.", timeout);
	(void) time(&now);
	if (logging) {
		syslog(LOG_INFO,
			"User %s timed out after %d seconds at %s",
			(pw ? pw -> pw_name : "unknown"), timeout, ctime(&now));
	}
	dologout(1);
}

yylex()
{
	static int cpos, state;
	register char *cp, *cp2;
	register struct tab *p;
	int n;
	char c, *strpbrk();
	char *copy();

	for (;;) {
		switch (state) {

		case CMD:
			(void) signal(SIGALRM, toolong);
			(void) alarm((unsigned) timeout);
			if (getline(cbuf, sizeof(cbuf)-1, stdin) == NULL) {
				reply(221, "You could at least say goodbye.");
				dologout(0);
			}
			(void) alarm(0);
#ifdef SETPROCTITLE
			if (strncasecmp(cbuf, "PASS", 4) != NULL)
				setproctitle("%s: %s", proctitle, cbuf);
#endif /* SETPROCTITLE */
			if ((cp = index(cbuf, '\r'))) {
				*cp++ = '\n';
				*cp = '\0';
			}
			if ((cp = strpbrk(cbuf, " \n")))
				cpos = cp - cbuf;
			if (cpos == 0)
				cpos = 4;
			c = cbuf[cpos];
			cbuf[cpos] = '\0';
			upper(cbuf);
			p = lookup(cmdtab, cbuf);
			cbuf[cpos] = c;
			if (p != 0) {
				if (p->implemented == 0) {
					nack(p->name);
					longjmp(errcatch,0);
					/* NOTREACHED */
				}
				state = p->state;
				*(char **)&yylval = p->name;
				return (p->token);
			}
			break;

		case SITECMD:
			if (cbuf[cpos] == ' ') {
				cpos++;
				return (SP);
			}
			cp = &cbuf[cpos];
			if ((cp2 = strpbrk(cp, " \n")))
				cpos = cp2 - cbuf;
			c = cbuf[cpos];
			cbuf[cpos] = '\0';
			upper(cp);
			p = lookup(sitetab, cp);
			cbuf[cpos] = c;
			if (p != 0) {
				if (p->implemented == 0) {
					state = CMD;
					nack(p->name);
					longjmp(errcatch,0);
					/* NOTREACHED */
				}
				state = p->state;
				*(char **)&yylval = p->name;
				return (p->token);
			}
			state = CMD;
			break;

		case OSTR:
			if (cbuf[cpos] == '\n') {
				state = CMD;
				return (CRLF);
			}
			/* FALLTHROUGH */

		case STR1:
		case ZSTR1:
		dostr1:
			if (cbuf[cpos] == ' ') {
				cpos++;
				state = state == OSTR ? STR2 : ++state;
				return (SP);
			}
			break;

		case ZSTR2:
			if (cbuf[cpos] == '\n') {
				state = CMD;
				return (CRLF);
			}
			/* FALLTHROUGH */

		case STR2:
			cp = &cbuf[cpos];
			n = strlen(cp);
			cpos += n - 1;
			/*
			 * Make sure the string is nonempty and \n terminated.
			 */
			if (n > 1 && cbuf[cpos] == '\n') {
				cbuf[cpos] = '\0';
				*(char **)&yylval = copy(cp);
				cbuf[cpos] = '\n';
				state = ARGS;
				return (STRING);
			}
			break;

		case NSTR:
			if (cbuf[cpos] == ' ') {
				cpos++;
				return (SP);
			}
			if (isdigit(cbuf[cpos])) {
				cp = &cbuf[cpos];
				while (isdigit(cbuf[++cpos]))
					;
				c = cbuf[cpos];
				cbuf[cpos] = '\0';
				yylval = atoi(cp);
				cbuf[cpos] = c;
				state = STR1;
				return (NUMBER);
			}
			state = STR1;
			goto dostr1;

		case ARGS:
			if (isdigit(cbuf[cpos])) {
				cp = &cbuf[cpos];
				while (isdigit(cbuf[++cpos]))
					;
				c = cbuf[cpos];
				cbuf[cpos] = '\0';
				yylval = atoi(cp);
				cbuf[cpos] = c;
				return (NUMBER);
			}
			switch (cbuf[cpos++]) {

			case '\n':
				state = CMD;
				return (CRLF);

			case ' ':
				return (SP);

			case ',':
				return (COMMA);

			case 'A':
			case 'a':
				return (A);

			case 'B':
			case 'b':
				return (B);

			case 'C':
			case 'c':
				return (C);

			case 'E':
			case 'e':
				return (E);

			case 'F':
			case 'f':
				return (F);

			case 'I':
			case 'i':
				return (I);

			case 'L':
			case 'l':
				return (L);

			case 'N':
			case 'n':
				return (N);

			case 'P':
			case 'p':
				return (P);

			case 'R':
			case 'r':
				return (R);

			case 'S':
			case 's':
				return (S);

			case 'T':
			case 't':
				return (T);

			}
			break;

		default:
			fatal("Unknown state in scanner.");
		}
		yyerror((char *) 0);
		state = CMD;
		longjmp(errcatch,0);
	}
}

upper(s)
	register char *s;
{
	while (*s != '\0') {
		if (islower(*s))
			*s = toupper(*s);
		s++;
	}
}

char *
copy(s)
	char *s;
{
	char *p;
	extern char *malloc(), *strcpy();

	p = malloc((unsigned) strlen(s) + 1);
	if (p == NULL)
		fatal("Ran out of memory.");
	(void) strcpy(p, s);
	return (p);
}

help(ctab, s)
	struct tab *ctab;
	char *s;
{
	register struct tab *c;
	register int width, NCMDS;
	char *type;

	if (ctab == sitetab)
		type = "SITE ";
	else
		type = "";
	width = 0, NCMDS = 0;
	for (c = ctab; c->name != NULL; c++) {
		int len = strlen(c->name);

		if (len > width)
			width = len;
		NCMDS++;
	}
	width = (width + 8) &~ 7;
	if (s == 0) {
		register int i, j, w;
		int columns, lines;

		lreply(214, "The following %scommands are recognized %s.",
		    type, "(* =>'s unimplemented)");
		columns = 76 / width;
		if (columns == 0)
			columns = 1;
		lines = (NCMDS + columns - 1) / columns;
		for (i = 0; i < lines; i++) {
			printf("   ");
			for (j = 0; j < columns; j++) {
				c = ctab + j * lines + i;
				printf("%s%c", c->name,
					c->implemented ? ' ' : '*');
				if (c + lines >= &ctab[NCMDS])
					break;
				w = strlen(c->name) + 1;
				while (w < width) {
					putchar(' ');
					w++;
				}
			}
			printf("\r\n");
		}
		(void) fflush(stdout);
		reply(214, "Direct comments to ftp-bugs@%s.", hostname);
		return;
	}
	upper(s);
	c = lookup(ctab, s);
	if (c == (struct tab *)0) {
		reply(502, "Unknown command %s.", s);
		return;
	}
	if (c->implemented)
		reply(214, "Syntax: %s%s %s", type, c->name, c->help);
	else
		reply(214, "%s%-*s\t%s; unimplemented.", type, width,
		    c->name, c->help);
}

sizecmd(filename)
char *filename;
{
	switch (type) {
	case TYPE_L:
	case TYPE_I: {
		struct stat stbuf;
		if (stat(filename, &stbuf) < 0 ||
		    (stbuf.st_mode&S_IFMT) != S_IFREG)
			reply(550, "%s: not a plain file.", filename);
		else
			reply(213, "%lu", stbuf.st_size);
		break;}
	case TYPE_A: {
		FILE *fin;
		register int c, count;
		struct stat stbuf;
		fin = fopen(filename, "r");
		if (fin == NULL) {
			perror_reply(550, filename);
			return;
		}
		if (fstat(fileno(fin), &stbuf) < 0 ||
		    (stbuf.st_mode&S_IFMT) != S_IFREG) {
			reply(550, "%s: not a plain file.", filename);
			(void) fclose(fin);
			return;
		}

		count = 0;
		while((c=getc(fin)) != EOF) {
			if (c == '\n')	/* will get expanded to \r\n */
				count++;
			count++;
		}
		(void) fclose(fin);

		reply(213, "%ld", count);
		break;}
	default:
		reply(504, "SIZE not implemented for Type %c.", "?AEIL"[type]);
	}
}