xref: /netbsd-src/bin/csh/lex.c (revision ce0bb6e8d2e560ecacbe865a848624f94498063b)
1 /*	$NetBSD: lex.c,v 1.7 1995/03/21 09:03:07 cgd Exp $	*/
2 
3 /*-
4  * Copyright (c) 1980, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)lex.c	8.1 (Berkeley) 5/31/93";
39 #else
40 static char rcsid[] = "$NetBSD: lex.c,v 1.7 1995/03/21 09:03:07 cgd Exp $";
41 #endif
42 #endif /* not lint */
43 
44 #include <sys/types.h>
45 #include <sys/ioctl.h>
46 #include <termios.h>
47 #include <errno.h>
48 #include <stdlib.h>
49 #include <string.h>
50 #include <unistd.h>
51 #if __STDC__
52 # include <stdarg.h>
53 #else
54 # include <varargs.h>
55 #endif
56 
57 #include "csh.h"
58 #include "extern.h"
59 
60 /*
61  * These lexical routines read input and form lists of words.
62  * There is some involved processing here, because of the complications
63  * of input buffering, and especially because of history substitution.
64  */
65 
66 static Char	*word __P((void));
67 static int	 getC1 __P((int));
68 static void	 getdol __P((void));
69 static void	 getexcl __P((int));
70 static struct Hist
71 		*findev __P((Char *, bool));
72 static void	 setexclp __P((Char *));
73 static int	 bgetc __P((void));
74 static void	 bfree __P((void));
75 static struct wordent
76 		*gethent __P((int));
77 static int	 matchs __P((Char *, Char *));
78 static int	 getsel __P((int *, int *, int));
79 static struct wordent
80 		*getsub __P((struct wordent *));
81 static Char	*subword __P((Char *, int, bool *));
82 static struct wordent
83 		*dosub __P((int, struct wordent *, bool));
84 
85 /*
86  * Peekc is a peek character for getC, peekread for readc.
87  * There is a subtlety here in many places... history routines
88  * will read ahead and then insert stuff into the input stream.
89  * If they push back a character then they must push it behind
90  * the text substituted by the history substitution.  On the other
91  * hand in several places we need 2 peek characters.  To make this
92  * all work, the history routines read with getC, and make use both
93  * of ungetC and unreadc.  The key observation is that the state
94  * of getC at the call of a history reference is such that calls
95  * to getC from the history routines will always yield calls of
96  * readc, unless this peeking is involved.  That is to say that during
97  * getexcl the variables lap, exclp, and exclnxt are all zero.
98  *
99  * Getdol invokes history substitution, hence the extra peek, peekd,
100  * which it can ungetD to be before history substitutions.
101  */
102 static Char peekc = 0, peekd = 0;
103 static Char peekread = 0;
104 
105 /* (Tail of) current word from ! subst */
106 static Char *exclp = NULL;
107 
108 /* The rest of the ! subst words */
109 static struct wordent *exclnxt = NULL;
110 
111 /* Count of remaining words in ! subst */
112 static int exclc = 0;
113 
114 /* "Globp" for alias resubstitution */
115 Char *alvecp = NULL;
116 int aret = F_SEEK;
117 
118 /*
119  * Labuf implements a general buffer for lookahead during lexical operations.
120  * Text which is to be placed in the input stream can be stuck here.
121  * We stick parsed ahead $ constructs during initial input,
122  * process id's from `$$', and modified variable values (from qualifiers
123  * during expansion in sh.dol.c) here.
124  */
125 static Char labuf[BUFSIZ];
126 
127 /*
128  * Lex returns to its caller not only a wordlist (as a "var" parameter)
129  * but also whether a history substitution occurred.  This is used in
130  * the main (process) routine to determine whether to echo, and also
131  * when called by the alias routine to determine whether to keep the
132  * argument list.
133  */
134 static bool hadhist = 0;
135 
136 /*
137  * Avoid alias expansion recursion via \!#
138  */
139 int     hleft;
140 
141 static Char getCtmp;
142 
143 #define getC(f)		((getCtmp = peekc) ? (peekc = 0, getCtmp) : getC1(f))
144 #define	ungetC(c)	peekc = c
145 #define	ungetD(c)	peekd = c
146 
147 int
148 lex(hp)
149     register struct wordent *hp;
150 {
151     register struct wordent *wdp;
152     int     c;
153 
154     btell(&lineloc);
155     hp->next = hp->prev = hp;
156     hp->word = STRNULL;
157     hadhist = 0;
158     do
159 	c = readc(0);
160     while (c == ' ' || c == '\t');
161     if (c == HISTSUB && intty)
162 	/* ^lef^rit	from tty is short !:s^lef^rit */
163 	getexcl(c);
164     else
165 	unreadc(c);
166     wdp = hp;
167     /*
168      * The following loop is written so that the links needed by freelex will
169      * be ready and rarin to go even if it is interrupted.
170      */
171     do {
172 	register struct wordent *new;
173 
174 	new = (struct wordent *) xmalloc((size_t) sizeof(*wdp));
175 	new->word = 0;
176 	new->prev = wdp;
177 	new->next = hp;
178 	wdp->next = new;
179 	wdp = new;
180 	wdp->word = word();
181     } while (wdp->word[0] != '\n');
182     hp->prev = wdp;
183     return (hadhist);
184 }
185 
186 void
187 prlex(fp, sp0)
188     FILE *fp;
189     struct wordent *sp0;
190 {
191     register struct wordent *sp = sp0->next;
192 
193     for (;;) {
194 	(void) fprintf(fp, "%s", vis_str(sp->word));
195 	sp = sp->next;
196 	if (sp == sp0)
197 	    break;
198 	if (sp->word[0] != '\n')
199 	    (void) fputc(' ', fp);
200     }
201 }
202 
203 void
204 copylex(hp, fp)
205     register struct wordent *hp;
206     register struct wordent *fp;
207 {
208     register struct wordent *wdp;
209 
210     wdp = hp;
211     fp = fp->next;
212     do {
213 	register struct wordent *new;
214 
215 	new = (struct wordent *) xmalloc((size_t) sizeof(*wdp));
216 	new->prev = wdp;
217 	new->next = hp;
218 	wdp->next = new;
219 	wdp = new;
220 	wdp->word = Strsave(fp->word);
221 	fp = fp->next;
222     } while (wdp->word[0] != '\n');
223     hp->prev = wdp;
224 }
225 
226 void
227 freelex(vp)
228     register struct wordent *vp;
229 {
230     register struct wordent *fp;
231 
232     while (vp->next != vp) {
233 	fp = vp->next;
234 	vp->next = fp->next;
235 	xfree((ptr_t) fp->word);
236 	xfree((ptr_t) fp);
237     }
238     vp->prev = vp;
239 }
240 
241 static Char *
242 word()
243 {
244     register Char c, c1;
245     register Char *wp;
246     Char    wbuf[BUFSIZ];
247     register bool dolflg;
248     register int i;
249 
250     wp = wbuf;
251     i = BUFSIZ - 4;
252 loop:
253     while ((c = getC(DOALL)) == ' ' || c == '\t')
254 	continue;
255     if (cmap(c, _META | _ESC))
256 	switch (c) {
257 	case '&':
258 	case '|':
259 	case '<':
260 	case '>':
261 	    *wp++ = c;
262 	    c1 = getC(DOALL);
263 	    if (c1 == c)
264 		*wp++ = c1;
265 	    else
266 		ungetC(c1);
267 	    goto ret;
268 
269 	case '#':
270 	    if (intty)
271 		break;
272 	    c = 0;
273 	    do {
274 		c1 = c;
275 		c = getC(0);
276 	    } while (c != '\n');
277 	    if (c1 == '\\')
278 		goto loop;
279 	    /* fall into ... */
280 
281 	case ';':
282 	case '(':
283 	case ')':
284 	case '\n':
285 	    *wp++ = c;
286 	    goto ret;
287 
288 	case '\\':
289 	    c = getC(0);
290 	    if (c == '\n') {
291 		if (onelflg == 1)
292 		    onelflg = 2;
293 		goto loop;
294 	    }
295 	    if (c != HIST)
296 		*wp++ = '\\', --i;
297 	    c |= QUOTE;
298 	}
299     c1 = 0;
300     dolflg = DOALL;
301     for (;;) {
302 	if (c1) {
303 	    if (c == c1) {
304 		c1 = 0;
305 		dolflg = DOALL;
306 	    }
307 	    else if (c == '\\') {
308 		c = getC(0);
309 		if (c == HIST)
310 		    c |= QUOTE;
311 		else {
312 		    if (c == '\n')
313 			/*
314 			 * if (c1 == '`') c = ' '; else
315 			 */
316 			c |= QUOTE;
317 		    ungetC(c);
318 		    c = '\\';
319 		}
320 	    }
321 	    else if (c == '\n') {
322 		seterror(ERR_UNMATCHED, c1);
323 		ungetC(c);
324 		break;
325 	    }
326 	}
327 	else if (cmap(c, _META | _QF | _QB | _ESC)) {
328 	    if (c == '\\') {
329 		c = getC(0);
330 		if (c == '\n') {
331 		    if (onelflg == 1)
332 			onelflg = 2;
333 		    break;
334 		}
335 		if (c != HIST)
336 		    *wp++ = '\\', --i;
337 		c |= QUOTE;
338 	    }
339 	    else if (cmap(c, _QF | _QB)) {	/* '"` */
340 		c1 = c;
341 		dolflg = c == '"' ? DOALL : DOEXCL;
342 	    }
343 	    else if (c != '#' || !intty) {
344 		ungetC(c);
345 		break;
346 	    }
347 	}
348 	if (--i > 0) {
349 	    *wp++ = c;
350 	    c = getC(dolflg);
351 	}
352 	else {
353 	    seterror(ERR_WTOOLONG);
354 	    wp = &wbuf[1];
355 	    break;
356 	}
357     }
358 ret:
359     *wp = 0;
360     return (Strsave(wbuf));
361 }
362 
363 static int
364 getC1(flag)
365     register int flag;
366 {
367     register Char c;
368 
369     while (1) {
370 	if ((c = peekc) != '\0') {
371 	    peekc = 0;
372 	    return (c);
373 	}
374 	if (lap) {
375 	    if ((c = *lap++) == 0)
376 		lap = 0;
377 	    else {
378 		if (cmap(c, _META | _QF | _QB))
379 		    c |= QUOTE;
380 		return (c);
381 	    }
382 	}
383 	if ((c = peekd) != '\0') {
384 	    peekd = 0;
385 	    return (c);
386 	}
387 	if (exclp) {
388 	    if ((c = *exclp++) != '\0')
389 		return (c);
390 	    if (exclnxt && --exclc >= 0) {
391 		exclnxt = exclnxt->next;
392 		setexclp(exclnxt->word);
393 		return (' ');
394 	    }
395 	    exclp = 0;
396 	    exclnxt = 0;
397 	}
398 	if (exclnxt) {
399 	    exclnxt = exclnxt->next;
400 	    if (--exclc < 0)
401 		exclnxt = 0;
402 	    else
403 		setexclp(exclnxt->word);
404 	    continue;
405 	}
406 	c = readc(0);
407 	if (c == '$' && (flag & DODOL)) {
408 	    getdol();
409 	    continue;
410 	}
411 	if (c == HIST && (flag & DOEXCL)) {
412 	    getexcl(0);
413 	    continue;
414 	}
415 	break;
416     }
417     return (c);
418 }
419 
420 static void
421 getdol()
422 {
423     register Char *np, *ep;
424     Char    name[4 * MAXVARLEN + 1];
425     register int c;
426     int     sc;
427     bool    special = 0, toolong;
428 
429     np = name, *np++ = '$';
430     c = sc = getC(DOEXCL);
431     if (any("\t \n", c)) {
432 	ungetD(c);
433 	ungetC('$' | QUOTE);
434 	return;
435     }
436     if (c == '{')
437 	*np++ = c, c = getC(DOEXCL);
438     if (c == '#' || c == '?')
439 	special++, *np++ = c, c = getC(DOEXCL);
440     *np++ = c;
441     switch (c) {
442 
443     case '<':
444     case '$':
445     case '!':
446 	if (special)
447 	    seterror(ERR_SPDOLLT);
448 	*np = 0;
449 	addla(name);
450 	return;
451 
452     case '\n':
453 	ungetD(c);
454 	np--;
455 	seterror(ERR_NEWLINE);
456 	*np = 0;
457 	addla(name);
458 	return;
459 
460     case '*':
461 	if (special)
462 	    seterror(ERR_SPSTAR);
463 	*np = 0;
464 	addla(name);
465 	return;
466 
467     default:
468 	toolong = 0;
469 	if (Isdigit(c)) {
470 #ifdef notdef
471 	    /* let $?0 pass for now */
472 	    if (special) {
473 		seterror(ERR_DIGIT);
474 		*np = 0;
475 		addla(name);
476 		return;
477 	    }
478 #endif
479 	    /* we know that np < &name[4] */
480 	    ep = &np[MAXVARLEN];
481 	    while ((c = getC(DOEXCL)) != '\0'){
482 		if (!Isdigit(c))
483 		    break;
484 		if (np < ep)
485 		    *np++ = c;
486 		else
487 		    toolong = 1;
488 	    }
489 	}
490 	else if (letter(c)) {
491 	    /* we know that np < &name[4] */
492 	    ep = &np[MAXVARLEN];
493 	    toolong = 0;
494 	    while ((c = getC(DOEXCL)) != '\0') {
495 		/* Bugfix for ${v123x} from Chris Torek, DAS DEC-90. */
496 		if (!letter(c) && !Isdigit(c))
497 		    break;
498 		if (np < ep)
499 		    *np++ = c;
500 		else
501 		    toolong = 1;
502 	    }
503 	}
504 	else {
505 	    *np = 0;
506 	    seterror(ERR_VARILL);
507 	    addla(name);
508 	    return;
509 	}
510 	if (toolong) {
511 	    seterror(ERR_VARTOOLONG);
512 	    *np = 0;
513 	    addla(name);
514 	    return;
515 	}
516 	break;
517     }
518     if (c == '[') {
519 	*np++ = c;
520 	/*
521 	 * Name up to here is a max of MAXVARLEN + 8.
522 	 */
523 	ep = &np[2 * MAXVARLEN + 8];
524 	do {
525 	    /*
526 	     * Michael Greim: Allow $ expansion to take place in selector
527 	     * expressions. (limits the number of characters returned)
528 	     */
529 	    c = getC(DOEXCL | DODOL);
530 	    if (c == '\n') {
531 		ungetD(c);
532 		np--;
533 		seterror(ERR_NLINDEX);
534 		*np = 0;
535 		addla(name);
536 		return;
537 	    }
538 	    if (np < ep)
539 		*np++ = c;
540 	} while (c != ']');
541 	*np = '\0';
542 	if (np >= ep) {
543 	    seterror(ERR_SELOVFL);
544 	    addla(name);
545 	    return;
546 	}
547 	c = getC(DOEXCL);
548     }
549     /*
550      * Name up to here is a max of 2 * MAXVARLEN + 8.
551      */
552     if (c == ':') {
553 	/*
554 	 * if the :g modifier is followed by a newline, then error right away!
555 	 * -strike
556 	 */
557 
558 	int     gmodflag = 0, amodflag = 0;
559 
560 	do {
561 	    *np++ = c, c = getC(DOEXCL);
562 	    if (c == 'g' || c == 'a') {
563 		if (c == 'g')
564 		    gmodflag++;
565 		else
566 		    amodflag++;
567 		*np++ = c; c = getC(DOEXCL);
568 	    }
569 	    if ((c == 'g' && !gmodflag) || (c == 'a' && !amodflag)) {
570 		if (c == 'g')
571 		    gmodflag++;
572 		else
573 		    amodflag++;
574 		*np++ = c; c = getC(DOEXCL);
575 	    }
576 	    *np++ = c;
577 	    /* scan s// [eichin:19910926.0512EST] */
578 	    if (c == 's') {
579 		int delimcnt = 2;
580 		int delim = getC(0);
581 		*np++ = delim;
582 
583 		if (!delim || letter(delim)
584 		    || Isdigit(delim) || any(" \t\n", delim)) {
585 		    seterror(ERR_BADSUBST);
586 		    break;
587 		}
588 		while ((c = getC(0)) != (-1)) {
589 		    *np++ = c;
590 		    if(c == delim) delimcnt--;
591 		    if(!delimcnt) break;
592 		}
593 		if(delimcnt) {
594 		    seterror(ERR_BADSUBST);
595 		    break;
596 		}
597 		c = 's';
598 	    }
599 	    if (!any("htrqxes", c)) {
600 		if ((amodflag || gmodflag) && c == '\n')
601 		    stderror(ERR_VARSYN);	/* strike */
602 		seterror(ERR_VARMOD, c);
603 		*np = 0;
604 		addla(name);
605 		return;
606 	    }
607 	}
608 	while ((c = getC(DOEXCL)) == ':');
609 	ungetD(c);
610     }
611     else
612 	ungetD(c);
613     if (sc == '{') {
614 	c = getC(DOEXCL);
615 	if (c != '}') {
616 	    ungetD(c);
617 	    seterror(ERR_MISSING, '}');
618 	    *np = 0;
619 	    addla(name);
620 	    return;
621 	}
622 	*np++ = c;
623     }
624     *np = 0;
625     addla(name);
626     return;
627 }
628 
629 void
630 addla(cp)
631     Char   *cp;
632 {
633     Char    buf[BUFSIZ];
634 
635     if (Strlen(cp) + (lap ? Strlen(lap) : 0) >=
636 	(sizeof(labuf) - 4) / sizeof(Char)) {
637 	seterror(ERR_EXPOVFL);
638 	return;
639     }
640     if (lap)
641 	(void) Strcpy(buf, lap);
642     (void) Strcpy(labuf, cp);
643     if (lap)
644 	(void) Strcat(labuf, buf);
645     lap = labuf;
646 }
647 
648 static Char lhsb[32];
649 static Char slhs[32];
650 static Char rhsb[64];
651 static int quesarg;
652 
653 static void
654 getexcl(sc)
655     int    sc;
656 {
657     register struct wordent *hp, *ip;
658     int     left, right, dol;
659     register int c;
660 
661     if (sc == 0) {
662 	sc = getC(0);
663 	if (sc != '{') {
664 	    ungetC(sc);
665 	    sc = 0;
666 	}
667     }
668     quesarg = -1;
669     lastev = eventno;
670     hp = gethent(sc);
671     if (hp == 0)
672 	return;
673     hadhist = 1;
674     dol = 0;
675     if (hp == alhistp)
676 	for (ip = hp->next->next; ip != alhistt; ip = ip->next)
677 	    dol++;
678     else
679 	for (ip = hp->next->next; ip != hp->prev; ip = ip->next)
680 	    dol++;
681     left = 0, right = dol;
682     if (sc == HISTSUB) {
683 	ungetC('s'), unreadc(HISTSUB), c = ':';
684 	goto subst;
685     }
686     c = getC(0);
687     if (!any(":^$*-%", c))
688 	goto subst;
689     left = right = -1;
690     if (c == ':') {
691 	c = getC(0);
692 	unreadc(c);
693 	if (letter(c) || c == '&') {
694 	    c = ':';
695 	    left = 0, right = dol;
696 	    goto subst;
697 	}
698     }
699     else
700 	ungetC(c);
701     if (!getsel(&left, &right, dol))
702 	return;
703     c = getC(0);
704     if (c == '*')
705 	ungetC(c), c = '-';
706     if (c == '-') {
707 	if (!getsel(&left, &right, dol))
708 	    return;
709 	c = getC(0);
710     }
711 subst:
712     exclc = right - left + 1;
713     while (--left >= 0)
714 	hp = hp->next;
715     if (sc == HISTSUB || c == ':') {
716 	do {
717 	    hp = getsub(hp);
718 	    c = getC(0);
719 	} while (c == ':');
720     }
721     unreadc(c);
722     if (sc == '{') {
723 	c = getC(0);
724 	if (c != '}')
725 	    seterror(ERR_BADBANG);
726     }
727     exclnxt = hp;
728 }
729 
730 static struct wordent *
731 getsub(en)
732     struct wordent *en;
733 {
734     register Char *cp;
735     int     delim;
736     register int c;
737     int     sc;
738     bool global;
739     Char    orhsb[sizeof(rhsb) / sizeof(Char)];
740 
741     do {
742 	exclnxt = 0;
743 	global = 0;
744 	sc = c = getC(0);
745 	if (c == 'g' || c == 'a') {
746 	    global |= (c == 'g') ? 1 : 2;
747 	    sc = c = getC(0);
748 	}
749 	if (((c =='g') && !(global & 1)) || ((c == 'a') && !(global & 2))) {
750 	    global |= (c == 'g') ? 1 : 2;
751 	    sc = c = getC(0);
752 	}
753 
754 	switch (c) {
755 	case 'p':
756 	    justpr++;
757 	    return (en);
758 
759 	case 'x':
760 	case 'q':
761 	    global |= 1;
762 
763 	    /* fall into ... */
764 
765 	case 'h':
766 	case 'r':
767 	case 't':
768 	case 'e':
769 	    break;
770 
771 	case '&':
772 	    if (slhs[0] == 0) {
773 		seterror(ERR_NOSUBST);
774 		return (en);
775 	    }
776 	    (void) Strcpy(lhsb, slhs);
777 	    break;
778 
779 #ifdef notdef
780 	case '~':
781 	    if (lhsb[0] == 0)
782 		goto badlhs;
783 	    break;
784 #endif
785 
786 	case 's':
787 	    delim = getC(0);
788 	    if (letter(delim) || Isdigit(delim) || any(" \t\n", delim)) {
789 		unreadc(delim);
790 		lhsb[0] = 0;
791 		seterror(ERR_BADSUBST);
792 		return (en);
793 	    }
794 	    cp = lhsb;
795 	    for (;;) {
796 		c = getC(0);
797 		if (c == '\n') {
798 		    unreadc(c);
799 		    break;
800 		}
801 		if (c == delim)
802 		    break;
803 		if (cp > &lhsb[sizeof(lhsb) / sizeof(Char) - 2]) {
804 		    lhsb[0] = 0;
805 		    seterror(ERR_BADSUBST);
806 		    return (en);
807 		}
808 		if (c == '\\') {
809 		    c = getC(0);
810 		    if (c != delim && c != '\\')
811 			*cp++ = '\\';
812 		}
813 		*cp++ = c;
814 	    }
815 	    if (cp != lhsb)
816 		*cp++ = 0;
817 	    else if (lhsb[0] == 0) {
818 		seterror(ERR_LHS);
819 		return (en);
820 	    }
821 	    cp = rhsb;
822 	    (void) Strcpy(orhsb, cp);
823 	    for (;;) {
824 		c = getC(0);
825 		if (c == '\n') {
826 		    unreadc(c);
827 		    break;
828 		}
829 		if (c == delim)
830 		    break;
831 #ifdef notdef
832 		if (c == '~') {
833 		    if (&cp[Strlen(orhsb)] > &rhsb[sizeof(rhsb) /
834 						   sizeof(Char) - 2])
835 			goto toorhs;
836 		    (void) Strcpy(cp, orhsb);
837 		    cp = Strend(cp);
838 		    continue;
839 		}
840 #endif
841 		if (cp > &rhsb[sizeof(rhsb) / sizeof(Char) - 2]) {
842 		    seterror(ERR_RHSLONG);
843 		    return (en);
844 		}
845 		if (c == '\\') {
846 		    c = getC(0);
847 		    if (c != delim /* && c != '~' */ )
848 			*cp++ = '\\';
849 		}
850 		*cp++ = c;
851 	    }
852 	    *cp++ = 0;
853 	    break;
854 
855 	default:
856 	    if (c == '\n')
857 		unreadc(c);
858 	    seterror(ERR_BADBANGMOD, c);
859 	    return (en);
860 	}
861 	(void) Strcpy(slhs, lhsb);
862 	if (exclc)
863 	    en = dosub(sc, en, global);
864     }
865     while ((c = getC(0)) == ':');
866     unreadc(c);
867     return (en);
868 }
869 
870 static struct wordent *
871 dosub(sc, en, global)
872     int     sc;
873     struct wordent *en;
874     bool global;
875 {
876     struct wordent lexi;
877     bool    didsub = 0, didone = 0;
878     struct wordent *hp = &lexi;
879     register struct wordent *wdp;
880     register int i = exclc;
881 
882     wdp = hp;
883     while (--i >= 0) {
884 	register struct wordent *new =
885 		(struct wordent *) xcalloc(1, sizeof *wdp);
886 
887 	new->word = 0;
888 	new->prev = wdp;
889 	new->next = hp;
890 	wdp->next = new;
891 	wdp = new;
892 	en = en->next;
893 	if (en->word) {
894 	    Char *tword, *otword;
895 
896 	    if ((global & 1) || didsub == 0) {
897 		tword = subword(en->word, sc, &didone);
898 		if (didone)
899 		    didsub = 1;
900 		if (global & 2) {
901 		    while (didone && tword != STRNULL) {
902 			otword = tword;
903 			tword = subword(otword, sc, &didone);
904 			if (Strcmp(tword, otword) == 0) {
905 			    xfree((ptr_t) otword);
906 			    break;
907 			}
908 			else
909 			    xfree((ptr_t) otword);
910 		    }
911 		}
912 	    }
913 	    else
914 		tword = Strsave(en->word);
915 	    wdp->word = tword;
916 	}
917     }
918     if (didsub == 0)
919 	seterror(ERR_MODFAIL);
920     hp->prev = wdp;
921     return (&enthist(-1000, &lexi, 0)->Hlex);
922 }
923 
924 static Char *
925 subword(cp, type, adid)
926     Char   *cp;
927     int     type;
928     bool   *adid;
929 {
930     Char    wbuf[BUFSIZ];
931     register Char *wp, *mp, *np;
932     register int i;
933 
934     *adid = 0;
935     switch (type) {
936 
937     case 'r':
938     case 'e':
939     case 'h':
940     case 't':
941     case 'q':
942     case 'x':
943 	wp = domod(cp, type);
944 	if (wp == 0)
945 	    return (Strsave(cp));
946 	*adid = 1;
947 	return (wp);
948 
949     default:
950 	wp = wbuf;
951 	i = BUFSIZ - 4;
952 	for (mp = cp; *mp; mp++)
953 	    if (matchs(mp, lhsb)) {
954 		for (np = cp; np < mp;)
955 		    *wp++ = *np++, --i;
956 		for (np = rhsb; *np; np++)
957 		    switch (*np) {
958 
959 		    case '\\':
960 			if (np[1] == '&')
961 			    np++;
962 			/* fall into ... */
963 
964 		    default:
965 			if (--i < 0) {
966 			    seterror(ERR_SUBOVFL);
967 			    return (STRNULL);
968 			}
969 			*wp++ = *np;
970 			continue;
971 
972 		    case '&':
973 			i -= Strlen(lhsb);
974 			if (i < 0) {
975 			    seterror(ERR_SUBOVFL);
976 			    return (STRNULL);
977 			}
978 			*wp = 0;
979 			(void) Strcat(wp, lhsb);
980 			wp = Strend(wp);
981 			continue;
982 		    }
983 		mp += Strlen(lhsb);
984 		i -= Strlen(mp);
985 		if (i < 0) {
986 		    seterror(ERR_SUBOVFL);
987 		    return (STRNULL);
988 		}
989 		*wp = 0;
990 		(void) Strcat(wp, mp);
991 		*adid = 1;
992 		return (Strsave(wbuf));
993 	    }
994 	return (Strsave(cp));
995     }
996 }
997 
998 Char   *
999 domod(cp, type)
1000     Char   *cp;
1001     int     type;
1002 {
1003     register Char *wp, *xp;
1004     register int c;
1005 
1006     switch (type) {
1007 
1008     case 'x':
1009     case 'q':
1010 	wp = Strsave(cp);
1011 	for (xp = wp; (c = *xp) != '\0'; xp++)
1012 	    if ((c != ' ' && c != '\t') || type == 'q')
1013 		*xp |= QUOTE;
1014 	return (wp);
1015 
1016     case 'h':
1017     case 't':
1018 	if (!any(short2str(cp), '/'))
1019 	    return (type == 't' ? Strsave(cp) : 0);
1020 	wp = Strend(cp);
1021 	while (*--wp != '/')
1022 	    continue;
1023 	if (type == 'h')
1024 	    xp = Strsave(cp), xp[wp - cp] = 0;
1025 	else
1026 	    xp = Strsave(wp + 1);
1027 	return (xp);
1028 
1029     case 'e':
1030     case 'r':
1031 	wp = Strend(cp);
1032 	for (wp--; wp >= cp && *wp != '/'; wp--)
1033 	    if (*wp == '.') {
1034 		if (type == 'e')
1035 		    xp = Strsave(wp + 1);
1036 		else
1037 		    xp = Strsave(cp), xp[wp - cp] = 0;
1038 		return (xp);
1039 	    }
1040 	return (Strsave(type == 'e' ? STRNULL : cp));
1041     default:
1042 	break;
1043     }
1044     return (0);
1045 }
1046 
1047 static int
1048 matchs(str, pat)
1049     register Char *str, *pat;
1050 {
1051     while (*str && *pat && *str == *pat)
1052 	str++, pat++;
1053     return (*pat == 0);
1054 }
1055 
1056 static int
1057 getsel(al, ar, dol)
1058     register int *al, *ar;
1059     int     dol;
1060 {
1061     register int c = getC(0);
1062     register int i;
1063     bool    first = *al < 0;
1064 
1065     switch (c) {
1066 
1067     case '%':
1068 	if (quesarg == -1) {
1069 	    seterror(ERR_BADBANGARG);
1070 	    return (0);
1071 	}
1072 	if (*al < 0)
1073 	    *al = quesarg;
1074 	*ar = quesarg;
1075 	break;
1076 
1077     case '-':
1078 	if (*al < 0) {
1079 	    *al = 0;
1080 	    *ar = dol - 1;
1081 	    unreadc(c);
1082 	}
1083 	return (1);
1084 
1085     case '^':
1086 	if (*al < 0)
1087 	    *al = 1;
1088 	*ar = 1;
1089 	break;
1090 
1091     case '$':
1092 	if (*al < 0)
1093 	    *al = dol;
1094 	*ar = dol;
1095 	break;
1096 
1097     case '*':
1098 	if (*al < 0)
1099 	    *al = 1;
1100 	*ar = dol;
1101 	if (*ar < *al) {
1102 	    *ar = 0;
1103 	    *al = 1;
1104 	    return (1);
1105 	}
1106 	break;
1107 
1108     default:
1109 	if (Isdigit(c)) {
1110 	    i = 0;
1111 	    while (Isdigit(c)) {
1112 		i = i * 10 + c - '0';
1113 		c = getC(0);
1114 	    }
1115 	    if (i < 0)
1116 		i = dol + 1;
1117 	    if (*al < 0)
1118 		*al = i;
1119 	    *ar = i;
1120 	}
1121 	else if (*al < 0)
1122 	    *al = 0, *ar = dol;
1123 	else
1124 	    *ar = dol - 1;
1125 	unreadc(c);
1126 	break;
1127     }
1128     if (first) {
1129 	c = getC(0);
1130 	unreadc(c);
1131 	if (any("-$*", c))
1132 	    return (1);
1133     }
1134     if (*al > *ar || *ar > dol) {
1135 	seterror(ERR_BADBANGARG);
1136 	return (0);
1137     }
1138     return (1);
1139 
1140 }
1141 
1142 static struct wordent *
1143 gethent(sc)
1144     int     sc;
1145 {
1146     register struct Hist *hp;
1147     register Char *np;
1148     register int c;
1149     int     event;
1150     bool    back = 0;
1151 
1152     c = sc == HISTSUB ? HIST : getC(0);
1153     if (c == HIST) {
1154 	if (alhistp)
1155 	    return (alhistp);
1156 	event = eventno;
1157     }
1158     else
1159 	switch (c) {
1160 
1161 	case ':':
1162 	case '^':
1163 	case '$':
1164 	case '*':
1165 	case '%':
1166 	    ungetC(c);
1167 	    if (lastev == eventno && alhistp)
1168 		return (alhistp);
1169 	    event = lastev;
1170 	    break;
1171 
1172 	case '#':		/* !# is command being typed in (mrh) */
1173 	    if (--hleft == 0) {
1174 		seterror(ERR_HISTLOOP);
1175 		return (0);
1176 	    }
1177 	    else
1178 		return (&paraml);
1179 	    /* NOTREACHED */
1180 
1181 	case '-':
1182 	    back = 1;
1183 	    c = getC(0);
1184 	    /* FALLSTHROUGH */
1185 
1186 	default:
1187 	    if (any("(=~", c)) {
1188 		unreadc(c);
1189 		ungetC(HIST);
1190 		return (0);
1191 	    }
1192 	    np = lhsb;
1193 	    event = 0;
1194 	    while (!cmap(c, _ESC | _META | _QF | _QB) && !any("${}:", c)) {
1195 		if (event != -1 && Isdigit(c))
1196 		    event = event * 10 + c - '0';
1197 		else
1198 		    event = -1;
1199 		if (np < &lhsb[sizeof(lhsb) / sizeof(Char) - 2])
1200 		    *np++ = c;
1201 		c = getC(0);
1202 	    }
1203 	    unreadc(c);
1204 	    if (np == lhsb) {
1205 		ungetC(HIST);
1206 		return (0);
1207 	    }
1208 	    *np++ = 0;
1209 	    if (event != -1) {
1210 		/*
1211 		 * History had only digits
1212 		 */
1213 		if (back)
1214 		    event = eventno + (alhistp == 0) - (event ? event : 0);
1215 		break;
1216 	    }
1217 	    hp = findev(lhsb, 0);
1218 	    if (hp)
1219 		lastev = hp->Hnum;
1220 	    return (&hp->Hlex);
1221 
1222 	case '?':
1223 	    np = lhsb;
1224 	    for (;;) {
1225 		c = getC(0);
1226 		if (c == '\n') {
1227 		    unreadc(c);
1228 		    break;
1229 		}
1230 		if (c == '?')
1231 		    break;
1232 		if (np < &lhsb[sizeof(lhsb) / sizeof(Char) - 2])
1233 		    *np++ = c;
1234 	    }
1235 	    if (np == lhsb) {
1236 		if (lhsb[0] == 0) {
1237 		    seterror(ERR_NOSEARCH);
1238 		    return (0);
1239 		}
1240 	    }
1241 	    else
1242 		*np++ = 0;
1243 	    hp = findev(lhsb, 1);
1244 	    if (hp)
1245 		lastev = hp->Hnum;
1246 	    return (&hp->Hlex);
1247 	}
1248 
1249     for (hp = Histlist.Hnext; hp; hp = hp->Hnext)
1250 	if (hp->Hnum == event) {
1251 	    hp->Href = eventno;
1252 	    lastev = hp->Hnum;
1253 	    return (&hp->Hlex);
1254 	}
1255     np = putn(event);
1256     seterror(ERR_NOEVENT, vis_str(np));
1257     return (0);
1258 }
1259 
1260 static struct Hist *
1261 findev(cp, anyarg)
1262     Char   *cp;
1263     bool    anyarg;
1264 {
1265     register struct Hist *hp;
1266 
1267     for (hp = Histlist.Hnext; hp; hp = hp->Hnext) {
1268 	Char   *dp;
1269 	register Char *p, *q;
1270 	register struct wordent *lp = hp->Hlex.next;
1271 	int     argno = 0;
1272 
1273 	/*
1274 	 * The entries added by alias substitution don't have a newline but do
1275 	 * have a negative event number. Savehist() trims off these entries,
1276 	 * but it happens before alias expansion, too early to delete those
1277 	 * from the previous command.
1278 	 */
1279 	if (hp->Hnum < 0)
1280 	    continue;
1281 	if (lp->word[0] == '\n')
1282 	    continue;
1283 	if (!anyarg) {
1284 	    p = cp;
1285 	    q = lp->word;
1286 	    do
1287 		if (!*p)
1288 		    return (hp);
1289 	    while (*p++ == *q++);
1290 	    continue;
1291 	}
1292 	do {
1293 	    for (dp = lp->word; *dp; dp++) {
1294 		p = cp;
1295 		q = dp;
1296 		do
1297 		    if (!*p) {
1298 			quesarg = argno;
1299 			return (hp);
1300 		    }
1301 		while (*p++ == *q++);
1302 	    }
1303 	    lp = lp->next;
1304 	    argno++;
1305 	} while (lp->word[0] != '\n');
1306     }
1307     seterror(ERR_NOEVENT, vis_str(cp));
1308     return (0);
1309 }
1310 
1311 
1312 static void
1313 setexclp(cp)
1314     register Char *cp;
1315 {
1316     if (cp && cp[0] == '\n')
1317 	return;
1318     exclp = cp;
1319 }
1320 
1321 void
1322 unreadc(c)
1323     int    c;
1324 {
1325     peekread = c;
1326 }
1327 
1328 int
1329 readc(wanteof)
1330     bool    wanteof;
1331 {
1332     register int c;
1333     static  sincereal;
1334 
1335     aret = F_SEEK;
1336     if ((c = peekread) != '\0') {
1337 	peekread = 0;
1338 	return (c);
1339     }
1340 top:
1341     aret = F_SEEK;
1342     if (alvecp) {
1343 	aret = A_SEEK;
1344 	if ((c = *alvecp++) != '\0')
1345 	    return (c);
1346 	if (alvec && *alvec) {
1347 		alvecp = *alvec++;
1348 		return (' ');
1349 	}
1350 	else {
1351 	    aret = F_SEEK;
1352 	    alvecp = NULL;
1353 	    return('\n');
1354 	}
1355     }
1356     if (alvec) {
1357 	if ((alvecp = *alvec) != '\0') {
1358 	    alvec++;
1359 	    goto top;
1360 	}
1361 	/* Infinite source! */
1362 	return ('\n');
1363     }
1364     if (evalp) {
1365 	aret = E_SEEK;
1366 	if ((c = *evalp++) != '\0')
1367 	    return (c);
1368 	if (evalvec && *evalvec) {
1369 	    evalp = *evalvec++;
1370 	    return (' ');
1371 	}
1372 	aret = F_SEEK;
1373 	evalp = 0;
1374     }
1375     if (evalvec) {
1376 	if (evalvec == (Char **) 1) {
1377 	    doneinp = 1;
1378 	    reset();
1379 	}
1380 	if ((evalp = *evalvec) != '\0') {
1381 	    evalvec++;
1382 	    goto top;
1383 	}
1384 	evalvec = (Char **) 1;
1385 	return ('\n');
1386     }
1387     do {
1388 	if (arginp == (Char *) 1 || onelflg == 1) {
1389 	    if (wanteof)
1390 		return (-1);
1391 	    exitstat();
1392 	}
1393 	if (arginp) {
1394 	    if ((c = *arginp++) == 0) {
1395 		arginp = (Char *) 1;
1396 		return ('\n');
1397 	    }
1398 	    return (c);
1399 	}
1400 reread:
1401 	c = bgetc();
1402 	if (c < 0) {
1403 	    struct termios tty;
1404 	    if (wanteof)
1405 		return (-1);
1406 	    /* was isatty but raw with ignoreeof yields problems */
1407 	    if (tcgetattr(SHIN, &tty) == 0 && (tty.c_lflag & ICANON))
1408 	    {
1409 		/* was 'short' for FILEC */
1410 		int     ctpgrp;
1411 
1412 		if (++sincereal > 25)
1413 		    goto oops;
1414 		if (tpgrp != -1 &&
1415 		    (ctpgrp = tcgetpgrp(FSHTTY)) != -1 &&
1416 		    tpgrp != ctpgrp) {
1417 		    (void) tcsetpgrp(FSHTTY, tpgrp);
1418 		    (void) killpg((pid_t) ctpgrp, SIGHUP);
1419 		    (void) fprintf(csherr, "Reset tty pgrp from %d to %d\n",
1420 				   ctpgrp, tpgrp);
1421 		    goto reread;
1422 		}
1423 		if (adrof(STRignoreeof)) {
1424 		    if (loginsh)
1425 			(void) fprintf(csherr,"\nUse \"logout\" to logout.\n");
1426 		    else
1427 			(void) fprintf(csherr,"\nUse \"exit\" to leave csh.\n");
1428 		    reset();
1429 		}
1430 		if (chkstop == 0)
1431 		    panystop(1);
1432 	    }
1433     oops:
1434 	    doneinp = 1;
1435 	    reset();
1436 	}
1437 	sincereal = 0;
1438 	if (c == '\n' && onelflg)
1439 	    onelflg--;
1440     } while (c == 0);
1441     return (c);
1442 }
1443 
1444 static int
1445 bgetc()
1446 {
1447     register int buf, off, c;
1448 
1449 #ifdef FILEC
1450     register int numleft = 0, roomleft;
1451     Char    ttyline[BUFSIZ];
1452 #endif
1453     char    tbuf[BUFSIZ + 1];
1454 
1455     if (cantell) {
1456 	if (fseekp < fbobp || fseekp > feobp) {
1457 	    fbobp = feobp = fseekp;
1458 	    (void) lseek(SHIN, fseekp, L_SET);
1459 	}
1460 	if (fseekp == feobp) {
1461 	    int     i;
1462 
1463 	    fbobp = feobp;
1464 	    do
1465 		c = read(SHIN, tbuf, BUFSIZ);
1466 	    while (c < 0 && errno == EINTR);
1467 	    if (c <= 0)
1468 		return (-1);
1469 	    for (i = 0; i < c; i++)
1470 		fbuf[0][i] = (unsigned char) tbuf[i];
1471 	    feobp += c;
1472 	}
1473 	c = fbuf[0][fseekp - fbobp];
1474 	fseekp++;
1475 	return (c);
1476     }
1477 
1478 again:
1479     buf = (int) fseekp / BUFSIZ;
1480     if (buf >= fblocks) {
1481 	register Char **nfbuf =
1482 	(Char **) xcalloc((size_t) (fblocks + 2),
1483 			  sizeof(Char **));
1484 
1485 	if (fbuf) {
1486 	    (void) blkcpy(nfbuf, fbuf);
1487 	    xfree((ptr_t) fbuf);
1488 	}
1489 	fbuf = nfbuf;
1490 	fbuf[fblocks] = (Char *) xcalloc(BUFSIZ, sizeof(Char));
1491 	fblocks++;
1492 	if (!intty)
1493 	    goto again;
1494     }
1495     if (fseekp >= feobp) {
1496 	buf = (int) feobp / BUFSIZ;
1497 	off = (int) feobp % BUFSIZ;
1498 	roomleft = BUFSIZ - off;
1499 
1500 #ifdef FILEC
1501 	roomleft = BUFSIZ - off;
1502 	for (;;) {
1503 	    if (filec && intty) {
1504 		c = numleft ? numleft : tenex(ttyline, BUFSIZ);
1505 		if (c > roomleft) {
1506 		    /* start with fresh buffer */
1507 		    feobp = fseekp = fblocks * BUFSIZ;
1508 		    numleft = c;
1509 		    goto again;
1510 		}
1511 		if (c > 0)
1512 		    memcpy(fbuf[buf] + off, ttyline, c * sizeof(Char));
1513 		numleft = 0;
1514 	    }
1515 	    else {
1516 #endif
1517 		c = read(SHIN, tbuf, roomleft);
1518 		if (c > 0) {
1519 		    int     i;
1520 		    Char   *ptr = fbuf[buf] + off;
1521 
1522 		    for (i = 0; i < c; i++)
1523 			ptr[i] = (unsigned char) tbuf[i];
1524 		}
1525 #ifdef FILEC
1526 	    }
1527 #endif
1528 	    if (c >= 0)
1529 		break;
1530 	    if (errno == EWOULDBLOCK) {
1531 		int     off = 0;
1532 
1533 		(void) ioctl(SHIN, FIONBIO, (ioctl_t) & off);
1534 	    }
1535 	    else if (errno != EINTR)
1536 		break;
1537 	}
1538 	if (c <= 0)
1539 	    return (-1);
1540 	feobp += c;
1541 #ifndef FILEC
1542 	goto again;
1543 #else
1544 	if (filec && !intty)
1545 	    goto again;
1546 #endif
1547     }
1548     c = fbuf[buf][(int) fseekp % BUFSIZ];
1549     fseekp++;
1550     return (c);
1551 }
1552 
1553 static void
1554 bfree()
1555 {
1556     register int sb, i;
1557 
1558     if (cantell)
1559 	return;
1560     if (whyles)
1561 	return;
1562     sb = (int) (fseekp - 1) / BUFSIZ;
1563     if (sb > 0) {
1564 	for (i = 0; i < sb; i++)
1565 	    xfree((ptr_t) fbuf[i]);
1566 	(void) blkcpy(fbuf, &fbuf[sb]);
1567 	fseekp -= BUFSIZ * sb;
1568 	feobp -= BUFSIZ * sb;
1569 	fblocks -= sb;
1570     }
1571 }
1572 
1573 void
1574 bseek(l)
1575     struct Ain   *l;
1576 {
1577     switch (aret = l->type) {
1578     case E_SEEK:
1579 	evalvec = l->a_seek;
1580 	evalp = l->c_seek;
1581 	return;
1582     case A_SEEK:
1583 	alvec = l->a_seek;
1584 	alvecp = l->c_seek;
1585 	return;
1586     case F_SEEK:
1587 	fseekp = l->f_seek;
1588 	return;
1589     default:
1590 	(void) fprintf(csherr, "Bad seek type %d\n", aret);
1591 	abort();
1592     }
1593 }
1594 
1595 void
1596 btell(l)
1597     struct Ain *l;
1598 {
1599     switch (l->type = aret) {
1600     case E_SEEK:
1601 	l->a_seek = evalvec;
1602 	l->c_seek = evalp;
1603 	return;
1604     case A_SEEK:
1605 	l->a_seek = alvec;
1606 	l->c_seek = alvecp;
1607 	return;
1608     case F_SEEK:
1609 	l->f_seek = fseekp;
1610 	l->a_seek = NULL;
1611 	return;
1612     default:
1613 	(void) fprintf(csherr, "Bad seek type %d\n", aret);
1614 	abort();
1615     }
1616 }
1617 
1618 void
1619 btoeof()
1620 {
1621     (void) lseek(SHIN, (off_t) 0, L_XTND);
1622     aret = F_SEEK;
1623     fseekp = feobp;
1624     alvec = NULL;
1625     alvecp = NULL;
1626     evalvec = NULL;
1627     evalp = NULL;
1628     wfree();
1629     bfree();
1630 }
1631 
1632 void
1633 settell()
1634 {
1635     cantell = 0;
1636     if (arginp || onelflg || intty)
1637 	return;
1638     if (lseek(SHIN, (off_t) 0, L_INCR) < 0 || errno == ESPIPE)
1639 	return;
1640     fbuf = (Char **) xcalloc(2, sizeof(Char **));
1641     fblocks = 1;
1642     fbuf[0] = (Char *) xcalloc(BUFSIZ, sizeof(Char));
1643     fseekp = fbobp = feobp = lseek(SHIN, (off_t) 0, L_INCR);
1644     cantell = 1;
1645 }
1646