xref: /freebsd/bin/sh/expand.c (revision a812392203d7c4c3f0db9d8a0f3391374c49c71f)
1 /*-
2  * Copyright (c) 1991, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 1997-2005
5  *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Kenneth Almquist.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 4. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #ifndef lint
36 #if 0
37 static char sccsid[] = "@(#)expand.c	8.5 (Berkeley) 5/15/95";
38 #endif
39 #endif /* not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/types.h>
44 #include <sys/time.h>
45 #include <sys/stat.h>
46 #include <dirent.h>
47 #include <errno.h>
48 #include <inttypes.h>
49 #include <limits.h>
50 #include <pwd.h>
51 #include <stdio.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 #include <wchar.h>
56 #include <wctype.h>
57 
58 /*
59  * Routines to expand arguments to commands.  We have to deal with
60  * backquotes, shell variables, and file metacharacters.
61  */
62 
63 #include "shell.h"
64 #include "main.h"
65 #include "nodes.h"
66 #include "eval.h"
67 #include "expand.h"
68 #include "syntax.h"
69 #include "parser.h"
70 #include "jobs.h"
71 #include "options.h"
72 #include "var.h"
73 #include "input.h"
74 #include "output.h"
75 #include "memalloc.h"
76 #include "error.h"
77 #include "mystring.h"
78 #include "arith.h"
79 #include "show.h"
80 #include "builtins.h"
81 
82 /*
83  * Structure specifying which parts of the string should be searched
84  * for IFS characters.
85  */
86 
87 struct ifsregion {
88 	struct ifsregion *next;	/* next region in list */
89 	int begoff;		/* offset of start of region */
90 	int endoff;		/* offset of end of region */
91 	int inquotes;		/* search for nul bytes only */
92 };
93 
94 
95 static char *expdest;			/* output of current string */
96 static struct nodelist *argbackq;	/* list of back quote expressions */
97 static struct ifsregion ifsfirst;	/* first struct in list of ifs regions */
98 static struct ifsregion *ifslastp;	/* last struct in list */
99 static struct arglist exparg;		/* holds expanded arg list */
100 
101 static char *argstr(char *, int);
102 static char *exptilde(char *, int);
103 static char *expari(char *);
104 static void expbackq(union node *, int, int);
105 static int subevalvar(char *, char *, int, int, int, int, int);
106 static char *evalvar(char *, int);
107 static int varisset(const char *, int);
108 static void varvalue(const char *, int, int, int);
109 static void recordregion(int, int, int);
110 static void removerecordregions(int);
111 static void ifsbreakup(char *, struct arglist *);
112 static void expandmeta(struct strlist *, int);
113 static void expmeta(char *, char *);
114 static void addfname(char *);
115 static struct strlist *expsort(struct strlist *);
116 static struct strlist *msort(struct strlist *, int);
117 static int patmatch(const char *, const char *, int);
118 static char *cvtnum(int, char *);
119 static int collate_range_cmp(wchar_t, wchar_t);
120 
121 static int
122 collate_range_cmp(wchar_t c1, wchar_t c2)
123 {
124 	static wchar_t s1[2], s2[2];
125 
126 	s1[0] = c1;
127 	s2[0] = c2;
128 	return (wcscoll(s1, s2));
129 }
130 
131 static char *
132 stputs_quotes(const char *data, const char *syntax, char *p)
133 {
134 	while (*data) {
135 		CHECKSTRSPACE(2, p);
136 		if (syntax[(int)*data] == CCTL)
137 			USTPUTC(CTLESC, p);
138 		USTPUTC(*data++, p);
139 	}
140 	return (p);
141 }
142 #define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
143 
144 /*
145  * Perform expansions on an argument, placing the resulting list of arguments
146  * in arglist.  Parameter expansion, command substitution and arithmetic
147  * expansion are always performed; additional expansions can be requested
148  * via flag (EXP_*).
149  * The result is left in the stack string.
150  * When arglist is NULL, perform here document expansion.
151  *
152  * Caution: this function uses global state and is not reentrant.
153  * However, a new invocation after an interrupted invocation is safe
154  * and will reset the global state for the new call.
155  */
156 void
157 expandarg(union node *arg, struct arglist *arglist, int flag)
158 {
159 	struct strlist *sp;
160 	char *p;
161 
162 	argbackq = arg->narg.backquote;
163 	STARTSTACKSTR(expdest);
164 	ifsfirst.next = NULL;
165 	ifslastp = NULL;
166 	argstr(arg->narg.text, flag);
167 	if (arglist == NULL) {
168 		STACKSTRNUL(expdest);
169 		return;			/* here document expanded */
170 	}
171 	STPUTC('\0', expdest);
172 	p = grabstackstr(expdest);
173 	exparg.lastp = &exparg.list;
174 	if (flag & EXP_FULL) {
175 		ifsbreakup(p, &exparg);
176 		*exparg.lastp = NULL;
177 		exparg.lastp = &exparg.list;
178 		expandmeta(exparg.list, flag);
179 	} else {
180 		sp = (struct strlist *)stalloc(sizeof (struct strlist));
181 		sp->text = p;
182 		*exparg.lastp = sp;
183 		exparg.lastp = &sp->next;
184 	}
185 	while (ifsfirst.next != NULL) {
186 		struct ifsregion *ifsp;
187 		INTOFF;
188 		ifsp = ifsfirst.next->next;
189 		ckfree(ifsfirst.next);
190 		ifsfirst.next = ifsp;
191 		INTON;
192 	}
193 	*exparg.lastp = NULL;
194 	if (exparg.list) {
195 		*arglist->lastp = exparg.list;
196 		arglist->lastp = exparg.lastp;
197 	}
198 }
199 
200 
201 
202 /*
203  * Perform parameter expansion, command substitution and arithmetic
204  * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
205  * Processing ends at a CTLENDVAR or CTLENDARI character as well as '\0'.
206  * This is used to expand word in ${var+word} etc.
207  * If EXP_FULL or EXP_CASE are set, keep and/or generate CTLESC
208  * characters to allow for further processing.
209  * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
210  */
211 static char *
212 argstr(char *p, int flag)
213 {
214 	char c;
215 	int quotes = flag & (EXP_FULL | EXP_CASE);	/* do CTLESC */
216 	int firsteq = 1;
217 	int split_lit;
218 	int lit_quoted;
219 
220 	split_lit = flag & EXP_SPLIT_LIT;
221 	lit_quoted = flag & EXP_LIT_QUOTED;
222 	flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
223 	if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
224 		p = exptilde(p, flag);
225 	for (;;) {
226 		CHECKSTRSPACE(2, expdest);
227 		switch (c = *p++) {
228 		case '\0':
229 			return (p - 1);
230 		case CTLENDVAR:
231 		case CTLENDARI:
232 			return (p);
233 		case CTLQUOTEMARK:
234 			lit_quoted = 1;
235 			/* "$@" syntax adherence hack */
236 			if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
237 				break;
238 			if ((flag & EXP_FULL) != 0)
239 				USTPUTC(c, expdest);
240 			break;
241 		case CTLQUOTEEND:
242 			lit_quoted = 0;
243 			break;
244 		case CTLESC:
245 			if (quotes)
246 				USTPUTC(c, expdest);
247 			c = *p++;
248 			USTPUTC(c, expdest);
249 			if (split_lit && !lit_quoted)
250 				recordregion(expdest - stackblock() -
251 				    (quotes ? 2 : 1),
252 				    expdest - stackblock(), 0);
253 			break;
254 		case CTLVAR:
255 			p = evalvar(p, flag);
256 			break;
257 		case CTLBACKQ:
258 		case CTLBACKQ|CTLQUOTE:
259 			expbackq(argbackq->n, c & CTLQUOTE, flag);
260 			argbackq = argbackq->next;
261 			break;
262 		case CTLARI:
263 			p = expari(p);
264 			break;
265 		case ':':
266 		case '=':
267 			/*
268 			 * sort of a hack - expand tildes in variable
269 			 * assignments (after the first '=' and after ':'s).
270 			 */
271 			USTPUTC(c, expdest);
272 			if (split_lit && !lit_quoted)
273 				recordregion(expdest - stackblock() - 1,
274 				    expdest - stackblock(), 0);
275 			if (flag & EXP_VARTILDE && *p == '~' &&
276 			    (c != '=' || firsteq)) {
277 				if (c == '=')
278 					firsteq = 0;
279 				p = exptilde(p, flag);
280 			}
281 			break;
282 		default:
283 			USTPUTC(c, expdest);
284 			if (split_lit && !lit_quoted)
285 				recordregion(expdest - stackblock() - 1,
286 				    expdest - stackblock(), 0);
287 		}
288 	}
289 }
290 
291 /*
292  * Perform tilde expansion, placing the result in the stack string and
293  * returning the next position in the input string to process.
294  */
295 static char *
296 exptilde(char *p, int flag)
297 {
298 	char c, *startp = p;
299 	struct passwd *pw;
300 	char *home;
301 	int quotes = flag & (EXP_FULL | EXP_CASE);
302 
303 	while ((c = *p) != '\0') {
304 		switch(c) {
305 		case CTLESC: /* This means CTL* are always considered quoted. */
306 		case CTLVAR:
307 		case CTLBACKQ:
308 		case CTLBACKQ | CTLQUOTE:
309 		case CTLARI:
310 		case CTLENDARI:
311 		case CTLQUOTEMARK:
312 			return (startp);
313 		case ':':
314 			if (flag & EXP_VARTILDE)
315 				goto done;
316 			break;
317 		case '/':
318 		case CTLENDVAR:
319 			goto done;
320 		}
321 		p++;
322 	}
323 done:
324 	*p = '\0';
325 	if (*(startp+1) == '\0') {
326 		home = lookupvar("HOME");
327 	} else {
328 		pw = getpwnam(startp+1);
329 		home = pw != NULL ? pw->pw_dir : NULL;
330 	}
331 	*p = c;
332 	if (home == NULL || *home == '\0')
333 		return (startp);
334 	if (quotes)
335 		STPUTS_QUOTES(home, DQSYNTAX, expdest);
336 	else
337 		STPUTS(home, expdest);
338 	return (p);
339 }
340 
341 
342 static void
343 removerecordregions(int endoff)
344 {
345 	if (ifslastp == NULL)
346 		return;
347 
348 	if (ifsfirst.endoff > endoff) {
349 		while (ifsfirst.next != NULL) {
350 			struct ifsregion *ifsp;
351 			INTOFF;
352 			ifsp = ifsfirst.next->next;
353 			ckfree(ifsfirst.next);
354 			ifsfirst.next = ifsp;
355 			INTON;
356 		}
357 		if (ifsfirst.begoff > endoff)
358 			ifslastp = NULL;
359 		else {
360 			ifslastp = &ifsfirst;
361 			ifsfirst.endoff = endoff;
362 		}
363 		return;
364 	}
365 
366 	ifslastp = &ifsfirst;
367 	while (ifslastp->next && ifslastp->next->begoff < endoff)
368 		ifslastp=ifslastp->next;
369 	while (ifslastp->next != NULL) {
370 		struct ifsregion *ifsp;
371 		INTOFF;
372 		ifsp = ifslastp->next->next;
373 		ckfree(ifslastp->next);
374 		ifslastp->next = ifsp;
375 		INTON;
376 	}
377 	if (ifslastp->endoff > endoff)
378 		ifslastp->endoff = endoff;
379 }
380 
381 /*
382  * Expand arithmetic expression.
383  * Note that flag is not required as digits never require CTLESC characters.
384  */
385 static char *
386 expari(char *p)
387 {
388 	char *q, *start;
389 	arith_t result;
390 	int begoff;
391 	int quoted;
392 	int adj;
393 
394 	quoted = *p++ == '"';
395 	begoff = expdest - stackblock();
396 	p = argstr(p, 0);
397 	removerecordregions(begoff);
398 	STPUTC('\0', expdest);
399 	start = stackblock() + begoff;
400 
401 	q = grabstackstr(expdest);
402 	result = arith(start);
403 	ungrabstackstr(q, expdest);
404 
405 	start = stackblock() + begoff;
406 	adj = start - expdest;
407 	STADJUST(adj, expdest);
408 
409 	CHECKSTRSPACE((int)(DIGITS(result) + 1), expdest);
410 	fmtstr(expdest, DIGITS(result), ARITH_FORMAT_STR, result);
411 	adj = strlen(expdest);
412 	STADJUST(adj, expdest);
413 	if (!quoted)
414 		recordregion(begoff, expdest - stackblock(), 0);
415 	return p;
416 }
417 
418 
419 /*
420  * Perform command substitution.
421  */
422 static void
423 expbackq(union node *cmd, int quoted, int flag)
424 {
425 	struct backcmd in;
426 	int i;
427 	char buf[128];
428 	char *p;
429 	char *dest = expdest;
430 	struct ifsregion saveifs, *savelastp;
431 	struct nodelist *saveargbackq;
432 	char lastc;
433 	int startloc = dest - stackblock();
434 	char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
435 	int quotes = flag & (EXP_FULL | EXP_CASE);
436 	size_t nnl;
437 
438 	INTOFF;
439 	saveifs = ifsfirst;
440 	savelastp = ifslastp;
441 	saveargbackq = argbackq;
442 	p = grabstackstr(dest);
443 	evalbackcmd(cmd, &in);
444 	ungrabstackstr(p, dest);
445 	ifsfirst = saveifs;
446 	ifslastp = savelastp;
447 	argbackq = saveargbackq;
448 
449 	p = in.buf;
450 	lastc = '\0';
451 	nnl = 0;
452 	/* Don't copy trailing newlines */
453 	for (;;) {
454 		if (--in.nleft < 0) {
455 			if (in.fd < 0)
456 				break;
457 			while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
458 			TRACE(("expbackq: read returns %d\n", i));
459 			if (i <= 0)
460 				break;
461 			p = buf;
462 			in.nleft = i - 1;
463 		}
464 		lastc = *p++;
465 		if (lastc != '\0') {
466 			if (lastc == '\n') {
467 				nnl++;
468 			} else {
469 				CHECKSTRSPACE(nnl + 2, dest);
470 				while (nnl > 0) {
471 					nnl--;
472 					USTPUTC('\n', dest);
473 				}
474 				if (quotes && syntax[(int)lastc] == CCTL)
475 					USTPUTC(CTLESC, dest);
476 				USTPUTC(lastc, dest);
477 			}
478 		}
479 	}
480 
481 	if (in.fd >= 0)
482 		close(in.fd);
483 	if (in.buf)
484 		ckfree(in.buf);
485 	if (in.jp)
486 		exitstatus = waitforjob(in.jp, (int *)NULL);
487 	if (quoted == 0)
488 		recordregion(startloc, dest - stackblock(), 0);
489 	TRACE(("expbackq: size=%td: \"%.*s\"\n",
490 		((dest - stackblock()) - startloc),
491 		(int)((dest - stackblock()) - startloc),
492 		stackblock() + startloc));
493 	expdest = dest;
494 	INTON;
495 }
496 
497 
498 
499 static int
500 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
501   int varflags, int quotes)
502 {
503 	char *startp;
504 	char *loc = NULL;
505 	char *q;
506 	int c = 0;
507 	struct nodelist *saveargbackq = argbackq;
508 	int amount;
509 
510 	argstr(p, (subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
511 	    subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX ?
512 	    EXP_CASE : 0) | EXP_TILDE);
513 	STACKSTRNUL(expdest);
514 	argbackq = saveargbackq;
515 	startp = stackblock() + startloc;
516 	if (str == NULL)
517 	    str = stackblock() + strloc;
518 
519 	switch (subtype) {
520 	case VSASSIGN:
521 		setvar(str, startp, 0);
522 		amount = startp - expdest;
523 		STADJUST(amount, expdest);
524 		varflags &= ~VSNUL;
525 		return 1;
526 
527 	case VSQUESTION:
528 		if (*p != CTLENDVAR) {
529 			outfmt(out2, "%s\n", startp);
530 			error((char *)NULL);
531 		}
532 		error("%.*s: parameter %snot set", (int)(p - str - 1),
533 		      str, (varflags & VSNUL) ? "null or "
534 					      : nullstr);
535 		return 0;
536 
537 	case VSTRIMLEFT:
538 		for (loc = startp; loc < str; loc++) {
539 			c = *loc;
540 			*loc = '\0';
541 			if (patmatch(str, startp, quotes)) {
542 				*loc = c;
543 				goto recordleft;
544 			}
545 			*loc = c;
546 			if (quotes && *loc == CTLESC)
547 				loc++;
548 		}
549 		return 0;
550 
551 	case VSTRIMLEFTMAX:
552 		for (loc = str - 1; loc >= startp;) {
553 			c = *loc;
554 			*loc = '\0';
555 			if (patmatch(str, startp, quotes)) {
556 				*loc = c;
557 				goto recordleft;
558 			}
559 			*loc = c;
560 			loc--;
561 			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
562 				for (q = startp; q < loc; q++)
563 					if (*q == CTLESC)
564 						q++;
565 				if (q > loc)
566 					loc--;
567 			}
568 		}
569 		return 0;
570 
571 	case VSTRIMRIGHT:
572 		for (loc = str - 1; loc >= startp;) {
573 			if (patmatch(str, loc, quotes)) {
574 				amount = loc - expdest;
575 				STADJUST(amount, expdest);
576 				return 1;
577 			}
578 			loc--;
579 			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
580 				for (q = startp; q < loc; q++)
581 					if (*q == CTLESC)
582 						q++;
583 				if (q > loc)
584 					loc--;
585 			}
586 		}
587 		return 0;
588 
589 	case VSTRIMRIGHTMAX:
590 		for (loc = startp; loc < str - 1; loc++) {
591 			if (patmatch(str, loc, quotes)) {
592 				amount = loc - expdest;
593 				STADJUST(amount, expdest);
594 				return 1;
595 			}
596 			if (quotes && *loc == CTLESC)
597 				loc++;
598 		}
599 		return 0;
600 
601 
602 	default:
603 		abort();
604 	}
605 
606 recordleft:
607 	amount = ((str - 1) - (loc - startp)) - expdest;
608 	STADJUST(amount, expdest);
609 	while (loc != str - 1)
610 		*startp++ = *loc++;
611 	return 1;
612 }
613 
614 
615 /*
616  * Expand a variable, and return a pointer to the next character in the
617  * input string.
618  */
619 
620 static char *
621 evalvar(char *p, int flag)
622 {
623 	int subtype;
624 	int varflags;
625 	char *var;
626 	const char *val;
627 	int patloc;
628 	int c;
629 	int set;
630 	int special;
631 	int startloc;
632 	int varlen;
633 	int varlenb;
634 	int easy;
635 	int quotes = flag & (EXP_FULL | EXP_CASE);
636 
637 	varflags = (unsigned char)*p++;
638 	subtype = varflags & VSTYPE;
639 	var = p;
640 	special = 0;
641 	if (! is_name(*p))
642 		special = 1;
643 	p = strchr(p, '=') + 1;
644 again: /* jump here after setting a variable with ${var=text} */
645 	if (varflags & VSLINENO) {
646 		set = 1;
647 		special = 1;
648 		val = NULL;
649 	} else if (special) {
650 		set = varisset(var, varflags & VSNUL);
651 		val = NULL;
652 	} else {
653 		val = bltinlookup(var, 1);
654 		if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
655 			val = NULL;
656 			set = 0;
657 		} else
658 			set = 1;
659 	}
660 	varlen = 0;
661 	startloc = expdest - stackblock();
662 	if (!set && uflag && *var != '@' && *var != '*') {
663 		switch (subtype) {
664 		case VSNORMAL:
665 		case VSTRIMLEFT:
666 		case VSTRIMLEFTMAX:
667 		case VSTRIMRIGHT:
668 		case VSTRIMRIGHTMAX:
669 		case VSLENGTH:
670 			error("%.*s: parameter not set", (int)(p - var - 1),
671 			    var);
672 		}
673 	}
674 	if (set && subtype != VSPLUS) {
675 		/* insert the value of the variable */
676 		if (special) {
677 			if (varflags & VSLINENO)
678 				STPUTBIN(var, p - var - 1, expdest);
679 			else
680 				varvalue(var, varflags & VSQUOTE, subtype, flag);
681 			if (subtype == VSLENGTH) {
682 				varlenb = expdest - stackblock() - startloc;
683 				varlen = varlenb;
684 				if (localeisutf8) {
685 					val = stackblock() + startloc;
686 					for (;val != expdest; val++)
687 						if ((*val & 0xC0) == 0x80)
688 							varlen--;
689 				}
690 				STADJUST(-varlenb, expdest);
691 			}
692 		} else {
693 			char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
694 								  : BASESYNTAX;
695 
696 			if (subtype == VSLENGTH) {
697 				for (;*val; val++)
698 					if (!localeisutf8 ||
699 					    (*val & 0xC0) != 0x80)
700 						varlen++;
701 			}
702 			else {
703 				if (quotes)
704 					STPUTS_QUOTES(val, syntax, expdest);
705 				else
706 					STPUTS(val, expdest);
707 
708 			}
709 		}
710 	}
711 
712 	if (subtype == VSPLUS)
713 		set = ! set;
714 
715 	easy = ((varflags & VSQUOTE) == 0 ||
716 		(*var == '@' && shellparam.nparam != 1));
717 
718 
719 	switch (subtype) {
720 	case VSLENGTH:
721 		expdest = cvtnum(varlen, expdest);
722 		goto record;
723 
724 	case VSNORMAL:
725 		if (!easy)
726 			break;
727 record:
728 		recordregion(startloc, expdest - stackblock(),
729 		    varflags & VSQUOTE || (ifsset() && ifsval()[0] == '\0' &&
730 		    (*var == '@' || *var == '*')));
731 		break;
732 
733 	case VSPLUS:
734 	case VSMINUS:
735 		if (!set) {
736 			argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
737 			    (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
738 			break;
739 		}
740 		if (easy)
741 			goto record;
742 		break;
743 
744 	case VSTRIMLEFT:
745 	case VSTRIMLEFTMAX:
746 	case VSTRIMRIGHT:
747 	case VSTRIMRIGHTMAX:
748 		if (!set)
749 			break;
750 		/*
751 		 * Terminate the string and start recording the pattern
752 		 * right after it
753 		 */
754 		STPUTC('\0', expdest);
755 		patloc = expdest - stackblock();
756 		if (subevalvar(p, NULL, patloc, subtype,
757 		    startloc, varflags, quotes) == 0) {
758 			int amount = (expdest - stackblock() - patloc) + 1;
759 			STADJUST(-amount, expdest);
760 		}
761 		/* Remove any recorded regions beyond start of variable */
762 		removerecordregions(startloc);
763 		goto record;
764 
765 	case VSASSIGN:
766 	case VSQUESTION:
767 		if (!set) {
768 			if (subevalvar(p, var, 0, subtype, startloc, varflags,
769 			    quotes)) {
770 				varflags &= ~VSNUL;
771 				/*
772 				 * Remove any recorded regions beyond
773 				 * start of variable
774 				 */
775 				removerecordregions(startloc);
776 				goto again;
777 			}
778 			break;
779 		}
780 		if (easy)
781 			goto record;
782 		break;
783 
784 	case VSERROR:
785 		c = p - var - 1;
786 		error("${%.*s%s}: Bad substitution", c, var,
787 		    (c > 0 && *p != CTLENDVAR) ? "..." : "");
788 
789 	default:
790 		abort();
791 	}
792 
793 	if (subtype != VSNORMAL) {	/* skip to end of alternative */
794 		int nesting = 1;
795 		for (;;) {
796 			if ((c = *p++) == CTLESC)
797 				p++;
798 			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
799 				if (set)
800 					argbackq = argbackq->next;
801 			} else if (c == CTLVAR) {
802 				if ((*p++ & VSTYPE) != VSNORMAL)
803 					nesting++;
804 			} else if (c == CTLENDVAR) {
805 				if (--nesting == 0)
806 					break;
807 			}
808 		}
809 	}
810 	return p;
811 }
812 
813 
814 
815 /*
816  * Test whether a specialized variable is set.
817  */
818 
819 static int
820 varisset(const char *name, int nulok)
821 {
822 
823 	if (*name == '!')
824 		return backgndpidset();
825 	else if (*name == '@' || *name == '*') {
826 		if (*shellparam.p == NULL)
827 			return 0;
828 
829 		if (nulok) {
830 			char **av;
831 
832 			for (av = shellparam.p; *av; av++)
833 				if (**av != '\0')
834 					return 1;
835 			return 0;
836 		}
837 	} else if (is_digit(*name)) {
838 		char *ap;
839 		long num;
840 
841 		errno = 0;
842 		num = strtol(name, NULL, 10);
843 		if (errno != 0 || num > shellparam.nparam)
844 			return 0;
845 
846 		if (num == 0)
847 			ap = arg0;
848 		else
849 			ap = shellparam.p[num - 1];
850 
851 		if (nulok && (ap == NULL || *ap == '\0'))
852 			return 0;
853 	}
854 	return 1;
855 }
856 
857 static void
858 strtodest(const char *p, int flag, int subtype, int quoted)
859 {
860 	if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
861 		STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
862 	else
863 		STPUTS(p, expdest);
864 }
865 
866 /*
867  * Add the value of a specialized variable to the stack string.
868  */
869 
870 static void
871 varvalue(const char *name, int quoted, int subtype, int flag)
872 {
873 	int num;
874 	char *p;
875 	int i;
876 	char sep[2];
877 	char **ap;
878 
879 	switch (*name) {
880 	case '$':
881 		num = rootpid;
882 		break;
883 	case '?':
884 		num = oexitstatus;
885 		break;
886 	case '#':
887 		num = shellparam.nparam;
888 		break;
889 	case '!':
890 		num = backgndpidval();
891 		break;
892 	case '-':
893 		for (i = 0 ; i < NOPTS ; i++) {
894 			if (optlist[i].val)
895 				STPUTC(optlist[i].letter, expdest);
896 		}
897 		return;
898 	case '@':
899 		if (flag & EXP_FULL && quoted) {
900 			for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
901 				strtodest(p, flag, subtype, quoted);
902 				if (*ap)
903 					STPUTC('\0', expdest);
904 			}
905 			return;
906 		}
907 		/* FALLTHROUGH */
908 	case '*':
909 		if (ifsset())
910 			sep[0] = ifsval()[0];
911 		else
912 			sep[0] = ' ';
913 		sep[1] = '\0';
914 		for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
915 			strtodest(p, flag, subtype, quoted);
916 			if (!*ap)
917 				break;
918 			if (sep[0])
919 				strtodest(sep, flag, subtype, quoted);
920 			else if (flag & EXP_FULL && !quoted && **ap != '\0')
921 				STPUTC('\0', expdest);
922 		}
923 		return;
924 	default:
925 		if (is_digit(*name)) {
926 			num = atoi(name);
927 			if (num == 0)
928 				p = arg0;
929 			else if (num > 0 && num <= shellparam.nparam)
930 				p = shellparam.p[num - 1];
931 			else
932 				return;
933 			strtodest(p, flag, subtype, quoted);
934 		}
935 		return;
936 	}
937 	expdest = cvtnum(num, expdest);
938 }
939 
940 
941 
942 /*
943  * Record the fact that we have to scan this region of the
944  * string for IFS characters.
945  */
946 
947 static void
948 recordregion(int start, int end, int inquotes)
949 {
950 	struct ifsregion *ifsp;
951 
952 	INTOFF;
953 	if (ifslastp == NULL) {
954 		ifsp = &ifsfirst;
955 	} else {
956 		if (ifslastp->endoff == start
957 		    && ifslastp->inquotes == inquotes) {
958 			/* extend previous area */
959 			ifslastp->endoff = end;
960 			INTON;
961 			return;
962 		}
963 		ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
964 		ifslastp->next = ifsp;
965 	}
966 	ifslastp = ifsp;
967 	ifslastp->next = NULL;
968 	ifslastp->begoff = start;
969 	ifslastp->endoff = end;
970 	ifslastp->inquotes = inquotes;
971 	INTON;
972 }
973 
974 
975 
976 /*
977  * Break the argument string into pieces based upon IFS and add the
978  * strings to the argument list.  The regions of the string to be
979  * searched for IFS characters have been stored by recordregion.
980  * CTLESC characters are preserved but have little effect in this pass
981  * other than escaping CTL* characters.  In particular, they do not escape
982  * IFS characters: that should be done with the ifsregion mechanism.
983  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
984  * This pass treats them as a regular character, making the string non-empty.
985  * Later, they are removed along with the other CTL* characters.
986  */
987 static void
988 ifsbreakup(char *string, struct arglist *arglist)
989 {
990 	struct ifsregion *ifsp;
991 	struct strlist *sp;
992 	char *start;
993 	char *p;
994 	char *q;
995 	const char *ifs;
996 	const char *ifsspc;
997 	int had_param_ch = 0;
998 
999 	start = string;
1000 
1001 	if (ifslastp == NULL) {
1002 		/* Return entire argument, IFS doesn't apply to any of it */
1003 		sp = (struct strlist *)stalloc(sizeof *sp);
1004 		sp->text = start;
1005 		*arglist->lastp = sp;
1006 		arglist->lastp = &sp->next;
1007 		return;
1008 	}
1009 
1010 	ifs = ifsset() ? ifsval() : " \t\n";
1011 
1012 	for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1013 		p = string + ifsp->begoff;
1014 		while (p < string + ifsp->endoff) {
1015 			q = p;
1016 			if (*p == CTLESC)
1017 				p++;
1018 			if (ifsp->inquotes) {
1019 				/* Only NULs (should be from "$@") end args */
1020 				had_param_ch = 1;
1021 				if (*p != 0) {
1022 					p++;
1023 					continue;
1024 				}
1025 				ifsspc = NULL;
1026 			} else {
1027 				if (!strchr(ifs, *p)) {
1028 					had_param_ch = 1;
1029 					p++;
1030 					continue;
1031 				}
1032 				ifsspc = strchr(" \t\n", *p);
1033 
1034 				/* Ignore IFS whitespace at start */
1035 				if (q == start && ifsspc != NULL) {
1036 					p++;
1037 					start = p;
1038 					continue;
1039 				}
1040 				had_param_ch = 0;
1041 			}
1042 
1043 			/* Save this argument... */
1044 			*q = '\0';
1045 			sp = (struct strlist *)stalloc(sizeof *sp);
1046 			sp->text = start;
1047 			*arglist->lastp = sp;
1048 			arglist->lastp = &sp->next;
1049 			p++;
1050 
1051 			if (ifsspc != NULL) {
1052 				/* Ignore further trailing IFS whitespace */
1053 				for (; p < string + ifsp->endoff; p++) {
1054 					q = p;
1055 					if (*p == CTLESC)
1056 						p++;
1057 					if (strchr(ifs, *p) == NULL) {
1058 						p = q;
1059 						break;
1060 					}
1061 					if (strchr(" \t\n", *p) == NULL) {
1062 						p++;
1063 						break;
1064 					}
1065 				}
1066 			}
1067 			start = p;
1068 		}
1069 	}
1070 
1071 	/*
1072 	 * Save anything left as an argument.
1073 	 * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1074 	 * generating 2 arguments, the second of which is empty.
1075 	 * Some recent clarification of the Posix spec say that it
1076 	 * should only generate one....
1077 	 */
1078 	if (had_param_ch || *start != 0) {
1079 		sp = (struct strlist *)stalloc(sizeof *sp);
1080 		sp->text = start;
1081 		*arglist->lastp = sp;
1082 		arglist->lastp = &sp->next;
1083 	}
1084 }
1085 
1086 
1087 static char expdir[PATH_MAX];
1088 #define expdir_end (expdir + sizeof(expdir))
1089 
1090 /*
1091  * Perform pathname generation and remove control characters.
1092  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1093  * The results are stored in the list exparg.
1094  */
1095 static void
1096 expandmeta(struct strlist *str, int flag __unused)
1097 {
1098 	char *p;
1099 	struct strlist **savelastp;
1100 	struct strlist *sp;
1101 	char c;
1102 
1103 	while (str) {
1104 		savelastp = exparg.lastp;
1105 		if (!fflag) {
1106 			p = str->text;
1107 			for (; (c = *p) != '\0'; p++) {
1108 				/* fast check for meta chars */
1109 				if (c == '*' || c == '?' || c == '[') {
1110 					INTOFF;
1111 					expmeta(expdir, str->text);
1112 					INTON;
1113 					break;
1114 				}
1115 			}
1116 		}
1117 		if (exparg.lastp == savelastp) {
1118 			/*
1119 			 * no matches
1120 			 */
1121 			*exparg.lastp = str;
1122 			rmescapes(str->text);
1123 			exparg.lastp = &str->next;
1124 		} else {
1125 			*exparg.lastp = NULL;
1126 			*savelastp = sp = expsort(*savelastp);
1127 			while (sp->next != NULL)
1128 				sp = sp->next;
1129 			exparg.lastp = &sp->next;
1130 		}
1131 		str = str->next;
1132 	}
1133 }
1134 
1135 
1136 /*
1137  * Do metacharacter (i.e. *, ?, [...]) expansion.
1138  */
1139 
1140 static void
1141 expmeta(char *enddir, char *name)
1142 {
1143 	const char *p;
1144 	const char *q;
1145 	const char *start;
1146 	char *endname;
1147 	int metaflag;
1148 	struct stat statb;
1149 	DIR *dirp;
1150 	struct dirent *dp;
1151 	int atend;
1152 	int matchdot;
1153 	int esc;
1154 	int namlen;
1155 
1156 	metaflag = 0;
1157 	start = name;
1158 	for (p = name; esc = 0, *p; p += esc + 1) {
1159 		if (*p == '*' || *p == '?')
1160 			metaflag = 1;
1161 		else if (*p == '[') {
1162 			q = p + 1;
1163 			if (*q == '!' || *q == '^')
1164 				q++;
1165 			for (;;) {
1166 				while (*q == CTLQUOTEMARK)
1167 					q++;
1168 				if (*q == CTLESC)
1169 					q++;
1170 				if (*q == '/' || *q == '\0')
1171 					break;
1172 				if (*++q == ']') {
1173 					metaflag = 1;
1174 					break;
1175 				}
1176 			}
1177 		} else if (*p == '\0')
1178 			break;
1179 		else if (*p == CTLQUOTEMARK)
1180 			continue;
1181 		else {
1182 			if (*p == CTLESC)
1183 				esc++;
1184 			if (p[esc] == '/') {
1185 				if (metaflag)
1186 					break;
1187 				start = p + esc + 1;
1188 			}
1189 		}
1190 	}
1191 	if (metaflag == 0) {	/* we've reached the end of the file name */
1192 		if (enddir != expdir)
1193 			metaflag++;
1194 		for (p = name ; ; p++) {
1195 			if (*p == CTLQUOTEMARK)
1196 				continue;
1197 			if (*p == CTLESC)
1198 				p++;
1199 			*enddir++ = *p;
1200 			if (*p == '\0')
1201 				break;
1202 			if (enddir == expdir_end)
1203 				return;
1204 		}
1205 		if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1206 			addfname(expdir);
1207 		return;
1208 	}
1209 	endname = name + (p - name);
1210 	if (start != name) {
1211 		p = name;
1212 		while (p < start) {
1213 			while (*p == CTLQUOTEMARK)
1214 				p++;
1215 			if (*p == CTLESC)
1216 				p++;
1217 			*enddir++ = *p++;
1218 			if (enddir == expdir_end)
1219 				return;
1220 		}
1221 	}
1222 	if (enddir == expdir) {
1223 		p = ".";
1224 	} else if (enddir == expdir + 1 && *expdir == '/') {
1225 		p = "/";
1226 	} else {
1227 		p = expdir;
1228 		enddir[-1] = '\0';
1229 	}
1230 	if ((dirp = opendir(p)) == NULL)
1231 		return;
1232 	if (enddir != expdir)
1233 		enddir[-1] = '/';
1234 	if (*endname == 0) {
1235 		atend = 1;
1236 	} else {
1237 		atend = 0;
1238 		*endname = '\0';
1239 		endname += esc + 1;
1240 	}
1241 	matchdot = 0;
1242 	p = start;
1243 	while (*p == CTLQUOTEMARK)
1244 		p++;
1245 	if (*p == CTLESC)
1246 		p++;
1247 	if (*p == '.')
1248 		matchdot++;
1249 	while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1250 		if (dp->d_name[0] == '.' && ! matchdot)
1251 			continue;
1252 		if (patmatch(start, dp->d_name, 0)) {
1253 			namlen = dp->d_namlen;
1254 			if (enddir + namlen + 1 > expdir_end)
1255 				continue;
1256 			memcpy(enddir, dp->d_name, namlen + 1);
1257 			if (atend)
1258 				addfname(expdir);
1259 			else {
1260 				if (dp->d_type != DT_UNKNOWN &&
1261 				    dp->d_type != DT_DIR &&
1262 				    dp->d_type != DT_LNK)
1263 					continue;
1264 				if (enddir + namlen + 2 > expdir_end)
1265 					continue;
1266 				enddir[namlen] = '/';
1267 				enddir[namlen + 1] = '\0';
1268 				expmeta(enddir + namlen + 1, endname);
1269 			}
1270 		}
1271 	}
1272 	closedir(dirp);
1273 	if (! atend)
1274 		endname[-esc - 1] = esc ? CTLESC : '/';
1275 }
1276 
1277 
1278 /*
1279  * Add a file name to the list.
1280  */
1281 
1282 static void
1283 addfname(char *name)
1284 {
1285 	char *p;
1286 	struct strlist *sp;
1287 	size_t len;
1288 
1289 	len = strlen(name);
1290 	p = stalloc(len + 1);
1291 	memcpy(p, name, len + 1);
1292 	sp = (struct strlist *)stalloc(sizeof *sp);
1293 	sp->text = p;
1294 	*exparg.lastp = sp;
1295 	exparg.lastp = &sp->next;
1296 }
1297 
1298 
1299 /*
1300  * Sort the results of file name expansion.  It calculates the number of
1301  * strings to sort and then calls msort (short for merge sort) to do the
1302  * work.
1303  */
1304 
1305 static struct strlist *
1306 expsort(struct strlist *str)
1307 {
1308 	int len;
1309 	struct strlist *sp;
1310 
1311 	len = 0;
1312 	for (sp = str ; sp ; sp = sp->next)
1313 		len++;
1314 	return msort(str, len);
1315 }
1316 
1317 
1318 static struct strlist *
1319 msort(struct strlist *list, int len)
1320 {
1321 	struct strlist *p, *q = NULL;
1322 	struct strlist **lpp;
1323 	int half;
1324 	int n;
1325 
1326 	if (len <= 1)
1327 		return list;
1328 	half = len >> 1;
1329 	p = list;
1330 	for (n = half ; --n >= 0 ; ) {
1331 		q = p;
1332 		p = p->next;
1333 	}
1334 	q->next = NULL;			/* terminate first half of list */
1335 	q = msort(list, half);		/* sort first half of list */
1336 	p = msort(p, len - half);		/* sort second half */
1337 	lpp = &list;
1338 	for (;;) {
1339 		if (strcmp(p->text, q->text) < 0) {
1340 			*lpp = p;
1341 			lpp = &p->next;
1342 			if ((p = *lpp) == NULL) {
1343 				*lpp = q;
1344 				break;
1345 			}
1346 		} else {
1347 			*lpp = q;
1348 			lpp = &q->next;
1349 			if ((q = *lpp) == NULL) {
1350 				*lpp = p;
1351 				break;
1352 			}
1353 		}
1354 	}
1355 	return list;
1356 }
1357 
1358 
1359 
1360 static wchar_t
1361 get_wc(const char **p)
1362 {
1363 	wchar_t c;
1364 	int chrlen;
1365 
1366 	chrlen = mbtowc(&c, *p, 4);
1367 	if (chrlen == 0)
1368 		return 0;
1369 	else if (chrlen == -1)
1370 		c = 0;
1371 	else
1372 		*p += chrlen;
1373 	return c;
1374 }
1375 
1376 
1377 /*
1378  * See if a character matches a character class, starting at the first colon
1379  * of "[:class:]".
1380  * If a valid character class is recognized, a pointer to the next character
1381  * after the final closing bracket is stored into *end, otherwise a null
1382  * pointer is stored into *end.
1383  */
1384 static int
1385 match_charclass(const char *p, wchar_t chr, const char **end)
1386 {
1387 	char name[20];
1388 	const char *nameend;
1389 	wctype_t cclass;
1390 
1391 	*end = NULL;
1392 	p++;
1393 	nameend = strstr(p, ":]");
1394 	if (nameend == NULL || (size_t)(nameend - p) >= sizeof(name) ||
1395 	    nameend == p)
1396 		return 0;
1397 	memcpy(name, p, nameend - p);
1398 	name[nameend - p] = '\0';
1399 	*end = nameend + 2;
1400 	cclass = wctype(name);
1401 	/* An unknown class matches nothing but is valid nevertheless. */
1402 	if (cclass == 0)
1403 		return 0;
1404 	return iswctype(chr, cclass);
1405 }
1406 
1407 
1408 /*
1409  * Returns true if the pattern matches the string.
1410  */
1411 
1412 static int
1413 patmatch(const char *pattern, const char *string, int squoted)
1414 {
1415 	const char *p, *q, *end;
1416 	const char *bt_p, *bt_q;
1417 	char c;
1418 	wchar_t wc, wc2;
1419 
1420 	p = pattern;
1421 	q = string;
1422 	bt_p = NULL;
1423 	bt_q = NULL;
1424 	for (;;) {
1425 		switch (c = *p++) {
1426 		case '\0':
1427 			if (*q != '\0')
1428 				goto backtrack;
1429 			return 1;
1430 		case CTLESC:
1431 			if (squoted && *q == CTLESC)
1432 				q++;
1433 			if (*q++ != *p++)
1434 				goto backtrack;
1435 			break;
1436 		case CTLQUOTEMARK:
1437 			continue;
1438 		case '?':
1439 			if (squoted && *q == CTLESC)
1440 				q++;
1441 			if (*q == '\0')
1442 				return 0;
1443 			if (localeisutf8) {
1444 				wc = get_wc(&q);
1445 				/*
1446 				 * A '?' does not match invalid UTF-8 but a
1447 				 * '*' does, so backtrack.
1448 				 */
1449 				if (wc == 0)
1450 					goto backtrack;
1451 			} else
1452 				wc = (unsigned char)*q++;
1453 			break;
1454 		case '*':
1455 			c = *p;
1456 			while (c == CTLQUOTEMARK || c == '*')
1457 				c = *++p;
1458 			/*
1459 			 * If the pattern ends here, we know the string
1460 			 * matches without needing to look at the rest of it.
1461 			 */
1462 			if (c == '\0')
1463 				return 1;
1464 			/*
1465 			 * First try the shortest match for the '*' that
1466 			 * could work. We can forget any earlier '*' since
1467 			 * there is no way having it match more characters
1468 			 * can help us, given that we are already here.
1469 			 */
1470 			bt_p = p;
1471 			bt_q = q;
1472 			break;
1473 		case '[': {
1474 			const char *endp;
1475 			int invert, found;
1476 			wchar_t chr;
1477 
1478 			endp = p;
1479 			if (*endp == '!' || *endp == '^')
1480 				endp++;
1481 			for (;;) {
1482 				while (*endp == CTLQUOTEMARK)
1483 					endp++;
1484 				if (*endp == 0)
1485 					goto dft;		/* no matching ] */
1486 				if (*endp == CTLESC)
1487 					endp++;
1488 				if (*++endp == ']')
1489 					break;
1490 			}
1491 			invert = 0;
1492 			if (*p == '!' || *p == '^') {
1493 				invert++;
1494 				p++;
1495 			}
1496 			found = 0;
1497 			if (squoted && *q == CTLESC)
1498 				q++;
1499 			if (*q == '\0')
1500 				return 0;
1501 			if (localeisutf8) {
1502 				chr = get_wc(&q);
1503 				if (chr == 0)
1504 					goto backtrack;
1505 			} else
1506 				chr = (unsigned char)*q++;
1507 			c = *p++;
1508 			do {
1509 				if (c == CTLQUOTEMARK)
1510 					continue;
1511 				if (c == '[' && *p == ':') {
1512 					found |= match_charclass(p, chr, &end);
1513 					if (end != NULL)
1514 						p = end;
1515 				}
1516 				if (c == CTLESC)
1517 					c = *p++;
1518 				if (localeisutf8 && c & 0x80) {
1519 					p--;
1520 					wc = get_wc(&p);
1521 					if (wc == 0) /* bad utf-8 */
1522 						return 0;
1523 				} else
1524 					wc = (unsigned char)c;
1525 				if (*p == '-' && p[1] != ']') {
1526 					p++;
1527 					while (*p == CTLQUOTEMARK)
1528 						p++;
1529 					if (*p == CTLESC)
1530 						p++;
1531 					if (localeisutf8) {
1532 						wc2 = get_wc(&p);
1533 						if (wc2 == 0) /* bad utf-8 */
1534 							return 0;
1535 					} else
1536 						wc2 = (unsigned char)*p++;
1537 					if (   collate_range_cmp(chr, wc) >= 0
1538 					    && collate_range_cmp(chr, wc2) <= 0
1539 					   )
1540 						found = 1;
1541 				} else {
1542 					if (chr == wc)
1543 						found = 1;
1544 				}
1545 			} while ((c = *p++) != ']');
1546 			if (found == invert)
1547 				goto backtrack;
1548 			break;
1549 		}
1550 dft:	        default:
1551 			if (squoted && *q == CTLESC)
1552 				q++;
1553 			if (*q == '\0')
1554 				return 0;
1555 			if (*q++ == c)
1556 				break;
1557 backtrack:
1558 			/*
1559 			 * If we have a mismatch (other than hitting the end
1560 			 * of the string), go back to the last '*' seen and
1561 			 * have it match one additional character.
1562 			 */
1563 			if (bt_p == NULL)
1564 				return 0;
1565 			if (squoted && *bt_q == CTLESC)
1566 				bt_q++;
1567 			if (*bt_q == '\0')
1568 				return 0;
1569 			bt_q++;
1570 			p = bt_p;
1571 			q = bt_q;
1572 			break;
1573 		}
1574 	}
1575 }
1576 
1577 
1578 
1579 /*
1580  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1581  */
1582 
1583 void
1584 rmescapes(char *str)
1585 {
1586 	char *p, *q;
1587 
1588 	p = str;
1589 	while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
1590 		if (*p++ == '\0')
1591 			return;
1592 	}
1593 	q = p;
1594 	while (*p) {
1595 		if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
1596 			p++;
1597 			continue;
1598 		}
1599 		if (*p == CTLESC)
1600 			p++;
1601 		*q++ = *p++;
1602 	}
1603 	*q = '\0';
1604 }
1605 
1606 
1607 
1608 /*
1609  * See if a pattern matches in a case statement.
1610  */
1611 
1612 int
1613 casematch(union node *pattern, const char *val)
1614 {
1615 	struct stackmark smark;
1616 	int result;
1617 	char *p;
1618 
1619 	setstackmark(&smark);
1620 	argbackq = pattern->narg.backquote;
1621 	STARTSTACKSTR(expdest);
1622 	ifslastp = NULL;
1623 	argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1624 	STPUTC('\0', expdest);
1625 	p = grabstackstr(expdest);
1626 	result = patmatch(p, val, 0);
1627 	popstackmark(&smark);
1628 	return result;
1629 }
1630 
1631 /*
1632  * Our own itoa().
1633  */
1634 
1635 static char *
1636 cvtnum(int num, char *buf)
1637 {
1638 	char temp[32];
1639 	int neg = num < 0;
1640 	char *p = temp + 31;
1641 
1642 	temp[31] = '\0';
1643 
1644 	do {
1645 		*--p = num % 10 + '0';
1646 	} while ((num /= 10) != 0);
1647 
1648 	if (neg)
1649 		*--p = '-';
1650 
1651 	STPUTS(p, buf);
1652 	return buf;
1653 }
1654 
1655 /*
1656  * Do most of the work for wordexp(3).
1657  */
1658 
1659 int
1660 wordexpcmd(int argc, char **argv)
1661 {
1662 	size_t len;
1663 	int i;
1664 
1665 	out1fmt("%08x", argc - 1);
1666 	for (i = 1, len = 0; i < argc; i++)
1667 		len += strlen(argv[i]);
1668 	out1fmt("%08x", (int)len);
1669 	for (i = 1; i < argc; i++)
1670 		outbin(argv[i], strlen(argv[i]) + 1, out1);
1671         return (0);
1672 }
1673