xref: /freebsd/bin/sh/expand.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a)
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 
57 /*
58  * Routines to expand arguments to commands.  We have to deal with
59  * backquotes, shell variables, and file metacharacters.
60  */
61 
62 #include "shell.h"
63 #include "main.h"
64 #include "nodes.h"
65 #include "eval.h"
66 #include "expand.h"
67 #include "syntax.h"
68 #include "parser.h"
69 #include "jobs.h"
70 #include "options.h"
71 #include "var.h"
72 #include "input.h"
73 #include "output.h"
74 #include "memalloc.h"
75 #include "error.h"
76 #include "mystring.h"
77 #include "arith.h"
78 #include "show.h"
79 
80 /*
81  * Structure specifying which parts of the string should be searched
82  * for IFS characters.
83  */
84 
85 struct ifsregion {
86 	struct ifsregion *next;	/* next region in list */
87 	int begoff;		/* offset of start of region */
88 	int endoff;		/* offset of end of region */
89 	int inquotes;		/* search for nul bytes only */
90 };
91 
92 
93 static char *expdest;			/* output of current string */
94 static struct nodelist *argbackq;	/* list of back quote expressions */
95 static struct ifsregion ifsfirst;	/* first struct in list of ifs regions */
96 static struct ifsregion *ifslastp;	/* last struct in list */
97 static struct arglist exparg;		/* holds expanded arg list */
98 
99 static void argstr(char *, int);
100 static char *exptilde(char *, int);
101 static void expbackq(union node *, int, int);
102 static int subevalvar(char *, char *, int, int, int, int, int);
103 static char *evalvar(char *, int);
104 static int varisset(char *, int);
105 static void varvalue(char *, int, int, int);
106 static void recordregion(int, int, int);
107 static void removerecordregions(int);
108 static void ifsbreakup(char *, struct arglist *);
109 static void expandmeta(struct strlist *, int);
110 static void expmeta(char *, char *);
111 static void addfname(char *);
112 static struct strlist *expsort(struct strlist *);
113 static struct strlist *msort(struct strlist *, int);
114 static char *cvtnum(int, char *);
115 static int collate_range_cmp(wchar_t, wchar_t);
116 
117 static int
118 collate_range_cmp(wchar_t c1, wchar_t c2)
119 {
120 	static wchar_t s1[2], s2[2];
121 
122 	s1[0] = c1;
123 	s2[0] = c2;
124 	return (wcscoll(s1, s2));
125 }
126 
127 /*
128  * Expand shell variables and backquotes inside a here document.
129  *	union node *arg		the document
130  *	int fd;			where to write the expanded version
131  */
132 
133 void
134 expandhere(union node *arg, int fd)
135 {
136 	expandarg(arg, (struct arglist *)NULL, 0);
137 	xwrite(fd, stackblock(), expdest - stackblock());
138 }
139 
140 static char *
141 stputs_quotes(const char *data, const char *syntax, char *p)
142 {
143 	while (*data) {
144 		CHECKSTRSPACE(2, p);
145 		if (syntax[(int)*data] == CCTL)
146 			USTPUTC(CTLESC, p);
147 		USTPUTC(*data++, p);
148 	}
149 	return (p);
150 }
151 #define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
152 
153 /*
154  * Perform expansions on an argument, placing the resulting list of arguments
155  * in arglist.  Parameter expansion, command substitution and arithmetic
156  * expansion are always performed; additional expansions can be requested
157  * via flag (EXP_*).
158  * The result is left in the stack string.
159  * When arglist is NULL, perform here document expansion.
160  *
161  * Caution: this function uses global state and is not reentrant.
162  * However, a new invocation after an interrupted invocation is safe
163  * and will reset the global state for the new call.
164  */
165 void
166 expandarg(union node *arg, struct arglist *arglist, int flag)
167 {
168 	struct strlist *sp;
169 	char *p;
170 
171 	argbackq = arg->narg.backquote;
172 	STARTSTACKSTR(expdest);
173 	ifsfirst.next = NULL;
174 	ifslastp = NULL;
175 	argstr(arg->narg.text, flag);
176 	if (arglist == NULL) {
177 		return;			/* here document expanded */
178 	}
179 	STPUTC('\0', expdest);
180 	p = grabstackstr(expdest);
181 	exparg.lastp = &exparg.list;
182 	/*
183 	 * TODO - EXP_REDIR
184 	 */
185 	if (flag & EXP_FULL) {
186 		ifsbreakup(p, &exparg);
187 		*exparg.lastp = NULL;
188 		exparg.lastp = &exparg.list;
189 		expandmeta(exparg.list, flag);
190 	} else {
191 		if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
192 			rmescapes(p);
193 		sp = (struct strlist *)stalloc(sizeof (struct strlist));
194 		sp->text = p;
195 		*exparg.lastp = sp;
196 		exparg.lastp = &sp->next;
197 	}
198 	while (ifsfirst.next != NULL) {
199 		struct ifsregion *ifsp;
200 		INTOFF;
201 		ifsp = ifsfirst.next->next;
202 		ckfree(ifsfirst.next);
203 		ifsfirst.next = ifsp;
204 		INTON;
205 	}
206 	*exparg.lastp = NULL;
207 	if (exparg.list) {
208 		*arglist->lastp = exparg.list;
209 		arglist->lastp = exparg.lastp;
210 	}
211 }
212 
213 
214 
215 /*
216  * Perform parameter expansion, command substitution and arithmetic
217  * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
218  * Processing ends at a CTLENDVAR character as well as '\0'.
219  * This is used to expand word in ${var+word} etc.
220  * If EXP_FULL, EXP_CASE or EXP_REDIR are set, keep and/or generate CTLESC
221  * characters to allow for further processing.
222  * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
223  */
224 static void
225 argstr(char *p, int flag)
226 {
227 	char c;
228 	int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);	/* do CTLESC */
229 	int firsteq = 1;
230 	int split_lit;
231 	int lit_quoted;
232 
233 	split_lit = flag & EXP_SPLIT_LIT;
234 	lit_quoted = flag & EXP_LIT_QUOTED;
235 	flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
236 	if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
237 		p = exptilde(p, flag);
238 	for (;;) {
239 		CHECKSTRSPACE(2, expdest);
240 		switch (c = *p++) {
241 		case '\0':
242 		case CTLENDVAR:
243 			goto breakloop;
244 		case CTLQUOTEMARK:
245 			lit_quoted = 1;
246 			/* "$@" syntax adherence hack */
247 			if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
248 				break;
249 			if ((flag & EXP_FULL) != 0)
250 				USTPUTC(c, expdest);
251 			break;
252 		case CTLQUOTEEND:
253 			lit_quoted = 0;
254 			break;
255 		case CTLESC:
256 			if (quotes)
257 				USTPUTC(c, expdest);
258 			c = *p++;
259 			USTPUTC(c, expdest);
260 			if (split_lit && !lit_quoted)
261 				recordregion(expdest - stackblock() -
262 				    (quotes ? 2 : 1),
263 				    expdest - stackblock(), 0);
264 			break;
265 		case CTLVAR:
266 			p = evalvar(p, flag);
267 			break;
268 		case CTLBACKQ:
269 		case CTLBACKQ|CTLQUOTE:
270 			expbackq(argbackq->n, c & CTLQUOTE, flag);
271 			argbackq = argbackq->next;
272 			break;
273 		case CTLENDARI:
274 			expari(flag);
275 			break;
276 		case ':':
277 		case '=':
278 			/*
279 			 * sort of a hack - expand tildes in variable
280 			 * assignments (after the first '=' and after ':'s).
281 			 */
282 			USTPUTC(c, expdest);
283 			if (split_lit && !lit_quoted)
284 				recordregion(expdest - stackblock() - 1,
285 				    expdest - stackblock(), 0);
286 			if (flag & EXP_VARTILDE && *p == '~' &&
287 			    (c != '=' || firsteq)) {
288 				if (c == '=')
289 					firsteq = 0;
290 				p = exptilde(p, flag);
291 			}
292 			break;
293 		default:
294 			USTPUTC(c, expdest);
295 			if (split_lit && !lit_quoted)
296 				recordregion(expdest - stackblock() - 1,
297 				    expdest - stackblock(), 0);
298 		}
299 	}
300 breakloop:;
301 }
302 
303 /*
304  * Perform tilde expansion, placing the result in the stack string and
305  * returning the next position in the input string to process.
306  */
307 static char *
308 exptilde(char *p, int flag)
309 {
310 	char c, *startp = p;
311 	struct passwd *pw;
312 	char *home;
313 	int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
314 
315 	while ((c = *p) != '\0') {
316 		switch(c) {
317 		case CTLESC: /* This means CTL* are always considered quoted. */
318 		case CTLVAR:
319 		case CTLBACKQ:
320 		case CTLBACKQ | CTLQUOTE:
321 		case CTLARI:
322 		case CTLENDARI:
323 		case CTLQUOTEMARK:
324 			return (startp);
325 		case ':':
326 			if (flag & EXP_VARTILDE)
327 				goto done;
328 			break;
329 		case '/':
330 		case CTLENDVAR:
331 			goto done;
332 		}
333 		p++;
334 	}
335 done:
336 	*p = '\0';
337 	if (*(startp+1) == '\0') {
338 		if ((home = lookupvar("HOME")) == NULL)
339 			goto lose;
340 	} else {
341 		if ((pw = getpwnam(startp+1)) == NULL)
342 			goto lose;
343 		home = pw->pw_dir;
344 	}
345 	if (*home == '\0')
346 		goto lose;
347 	*p = c;
348 	if (quotes)
349 		STPUTS_QUOTES(home, SQSYNTAX, expdest);
350 	else
351 		STPUTS(home, expdest);
352 	return (p);
353 lose:
354 	*p = c;
355 	return (startp);
356 }
357 
358 
359 static void
360 removerecordregions(int endoff)
361 {
362 	if (ifslastp == NULL)
363 		return;
364 
365 	if (ifsfirst.endoff > endoff) {
366 		while (ifsfirst.next != NULL) {
367 			struct ifsregion *ifsp;
368 			INTOFF;
369 			ifsp = ifsfirst.next->next;
370 			ckfree(ifsfirst.next);
371 			ifsfirst.next = ifsp;
372 			INTON;
373 		}
374 		if (ifsfirst.begoff > endoff)
375 			ifslastp = NULL;
376 		else {
377 			ifslastp = &ifsfirst;
378 			ifsfirst.endoff = endoff;
379 		}
380 		return;
381 	}
382 
383 	ifslastp = &ifsfirst;
384 	while (ifslastp->next && ifslastp->next->begoff < endoff)
385 		ifslastp=ifslastp->next;
386 	while (ifslastp->next != NULL) {
387 		struct ifsregion *ifsp;
388 		INTOFF;
389 		ifsp = ifslastp->next->next;
390 		ckfree(ifslastp->next);
391 		ifslastp->next = ifsp;
392 		INTON;
393 	}
394 	if (ifslastp->endoff > endoff)
395 		ifslastp->endoff = endoff;
396 }
397 
398 /*
399  * Expand arithmetic expression.  Backup to start of expression,
400  * evaluate, place result in (backed up) result, adjust string position.
401  */
402 void
403 expari(int flag)
404 {
405 	char *p, *q, *start;
406 	arith_t result;
407 	int begoff;
408 	int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
409 	int quoted;
410 
411 	/*
412 	 * This routine is slightly over-complicated for
413 	 * efficiency.  First we make sure there is
414 	 * enough space for the result, which may be bigger
415 	 * than the expression.  Next we
416 	 * scan backwards looking for the start of arithmetic.  If the
417 	 * next previous character is a CTLESC character, then we
418 	 * have to rescan starting from the beginning since CTLESC
419 	 * characters have to be processed left to right.
420 	 */
421 	CHECKSTRSPACE(DIGITS(result) - 2, expdest);
422 	USTPUTC('\0', expdest);
423 	start = stackblock();
424 	p = expdest - 2;
425 	while (p >= start && *p != CTLARI)
426 		--p;
427 	if (p < start || *p != CTLARI)
428 		error("missing CTLARI (shouldn't happen)");
429 	if (p > start && *(p - 1) == CTLESC)
430 		for (p = start; *p != CTLARI; p++)
431 			if (*p == CTLESC)
432 				p++;
433 
434 	if (p[1] == '"')
435 		quoted=1;
436 	else
437 		quoted=0;
438 	begoff = p - start;
439 	removerecordregions(begoff);
440 	if (quotes)
441 		rmescapes(p+2);
442 	q = grabstackstr(expdest);
443 	result = arith(p+2);
444 	ungrabstackstr(q, expdest);
445 	fmtstr(p, DIGITS(result), ARITH_FORMAT_STR, result);
446 	while (*p++)
447 		;
448 	if (quoted == 0)
449 		recordregion(begoff, p - 1 - start, 0);
450 	result = expdest - p + 1;
451 	STADJUST(-result, expdest);
452 }
453 
454 
455 /*
456  * Perform command substitution.
457  */
458 static void
459 expbackq(union node *cmd, int quoted, int flag)
460 {
461 	struct backcmd in;
462 	int i;
463 	char buf[128];
464 	char *p;
465 	char *dest = expdest;
466 	struct ifsregion saveifs, *savelastp;
467 	struct nodelist *saveargbackq;
468 	char lastc;
469 	int startloc = dest - stackblock();
470 	char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
471 	int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
472 	int nnl;
473 
474 	INTOFF;
475 	saveifs = ifsfirst;
476 	savelastp = ifslastp;
477 	saveargbackq = argbackq;
478 	p = grabstackstr(dest);
479 	evalbackcmd(cmd, &in);
480 	ungrabstackstr(p, dest);
481 	ifsfirst = saveifs;
482 	ifslastp = savelastp;
483 	argbackq = saveargbackq;
484 
485 	p = in.buf;
486 	lastc = '\0';
487 	nnl = 0;
488 	/* Don't copy trailing newlines */
489 	for (;;) {
490 		if (--in.nleft < 0) {
491 			if (in.fd < 0)
492 				break;
493 			while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
494 			TRACE(("expbackq: read returns %d\n", i));
495 			if (i <= 0)
496 				break;
497 			p = buf;
498 			in.nleft = i - 1;
499 		}
500 		lastc = *p++;
501 		if (lastc != '\0') {
502 			if (lastc == '\n') {
503 				nnl++;
504 			} else {
505 				CHECKSTRSPACE(nnl + 2, dest);
506 				while (nnl > 0) {
507 					nnl--;
508 					USTPUTC('\n', dest);
509 				}
510 				if (quotes && syntax[(int)lastc] == CCTL)
511 					USTPUTC(CTLESC, dest);
512 				USTPUTC(lastc, dest);
513 			}
514 		}
515 	}
516 
517 	if (in.fd >= 0)
518 		close(in.fd);
519 	if (in.buf)
520 		ckfree(in.buf);
521 	if (in.jp)
522 		exitstatus = waitforjob(in.jp, (int *)NULL);
523 	if (quoted == 0)
524 		recordregion(startloc, dest - stackblock(), 0);
525 	TRACE(("expbackq: size=%td: \"%.*s\"\n",
526 		((dest - stackblock()) - startloc),
527 		(int)((dest - stackblock()) - startloc),
528 		stackblock() + startloc));
529 	expdest = dest;
530 	INTON;
531 }
532 
533 
534 
535 static int
536 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
537   int varflags, int quotes)
538 {
539 	char *startp;
540 	char *loc = NULL;
541 	char *q;
542 	int c = 0;
543 	struct nodelist *saveargbackq = argbackq;
544 	int amount;
545 
546 	argstr(p, (subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
547 	    subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX ?
548 	    EXP_CASE : 0) | EXP_TILDE);
549 	STACKSTRNUL(expdest);
550 	argbackq = saveargbackq;
551 	startp = stackblock() + startloc;
552 	if (str == NULL)
553 	    str = stackblock() + strloc;
554 
555 	switch (subtype) {
556 	case VSASSIGN:
557 		setvar(str, startp, 0);
558 		amount = startp - expdest;
559 		STADJUST(amount, expdest);
560 		varflags &= ~VSNUL;
561 		return 1;
562 
563 	case VSQUESTION:
564 		if (*p != CTLENDVAR) {
565 			outfmt(out2, "%s\n", startp);
566 			error((char *)NULL);
567 		}
568 		error("%.*s: parameter %snot set", (int)(p - str - 1),
569 		      str, (varflags & VSNUL) ? "null or "
570 					      : nullstr);
571 		return 0;
572 
573 	case VSTRIMLEFT:
574 		for (loc = startp; loc < str; loc++) {
575 			c = *loc;
576 			*loc = '\0';
577 			if (patmatch(str, startp, quotes)) {
578 				*loc = c;
579 				goto recordleft;
580 			}
581 			*loc = c;
582 			if (quotes && *loc == CTLESC)
583 				loc++;
584 		}
585 		return 0;
586 
587 	case VSTRIMLEFTMAX:
588 		for (loc = str - 1; loc >= startp;) {
589 			c = *loc;
590 			*loc = '\0';
591 			if (patmatch(str, startp, quotes)) {
592 				*loc = c;
593 				goto recordleft;
594 			}
595 			*loc = c;
596 			loc--;
597 			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
598 				for (q = startp; q < loc; q++)
599 					if (*q == CTLESC)
600 						q++;
601 				if (q > loc)
602 					loc--;
603 			}
604 		}
605 		return 0;
606 
607 	case VSTRIMRIGHT:
608 		for (loc = str - 1; loc >= startp;) {
609 			if (patmatch(str, loc, quotes)) {
610 				amount = loc - expdest;
611 				STADJUST(amount, expdest);
612 				return 1;
613 			}
614 			loc--;
615 			if (quotes && loc > startp && *(loc - 1) == CTLESC) {
616 				for (q = startp; q < loc; q++)
617 					if (*q == CTLESC)
618 						q++;
619 				if (q > loc)
620 					loc--;
621 			}
622 		}
623 		return 0;
624 
625 	case VSTRIMRIGHTMAX:
626 		for (loc = startp; loc < str - 1; loc++) {
627 			if (patmatch(str, loc, quotes)) {
628 				amount = loc - expdest;
629 				STADJUST(amount, expdest);
630 				return 1;
631 			}
632 			if (quotes && *loc == CTLESC)
633 				loc++;
634 		}
635 		return 0;
636 
637 
638 	default:
639 		abort();
640 	}
641 
642 recordleft:
643 	amount = ((str - 1) - (loc - startp)) - expdest;
644 	STADJUST(amount, expdest);
645 	while (loc != str - 1)
646 		*startp++ = *loc++;
647 	return 1;
648 }
649 
650 
651 /*
652  * Expand a variable, and return a pointer to the next character in the
653  * input string.
654  */
655 
656 static char *
657 evalvar(char *p, int flag)
658 {
659 	int subtype;
660 	int varflags;
661 	char *var;
662 	char *val;
663 	int patloc;
664 	int c;
665 	int set;
666 	int special;
667 	int startloc;
668 	int varlen;
669 	int varlenb;
670 	int easy;
671 	int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
672 
673 	varflags = (unsigned char)*p++;
674 	subtype = varflags & VSTYPE;
675 	var = p;
676 	special = 0;
677 	if (! is_name(*p))
678 		special = 1;
679 	p = strchr(p, '=') + 1;
680 again: /* jump here after setting a variable with ${var=text} */
681 	if (varflags & VSLINENO) {
682 		set = 1;
683 		special = 0;
684 		val = var;
685 		p[-1] = '\0';	/* temporarily overwrite '=' to have \0
686 				   terminated string */
687 	} else if (special) {
688 		set = varisset(var, varflags & VSNUL);
689 		val = NULL;
690 	} else {
691 		val = bltinlookup(var, 1);
692 		if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
693 			val = NULL;
694 			set = 0;
695 		} else
696 			set = 1;
697 	}
698 	varlen = 0;
699 	startloc = expdest - stackblock();
700 	if (!set && uflag && *var != '@' && *var != '*') {
701 		switch (subtype) {
702 		case VSNORMAL:
703 		case VSTRIMLEFT:
704 		case VSTRIMLEFTMAX:
705 		case VSTRIMRIGHT:
706 		case VSTRIMRIGHTMAX:
707 		case VSLENGTH:
708 			error("%.*s: parameter not set", (int)(p - var - 1),
709 			    var);
710 		}
711 	}
712 	if (set && subtype != VSPLUS) {
713 		/* insert the value of the variable */
714 		if (special) {
715 			varvalue(var, varflags & VSQUOTE, subtype, flag);
716 			if (subtype == VSLENGTH) {
717 				varlenb = expdest - stackblock() - startloc;
718 				varlen = varlenb;
719 				if (localeisutf8) {
720 					val = stackblock() + startloc;
721 					for (;val != expdest; val++)
722 						if ((*val & 0xC0) == 0x80)
723 							varlen--;
724 				}
725 				STADJUST(-varlenb, expdest);
726 			}
727 		} else {
728 			char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
729 								  : BASESYNTAX;
730 
731 			if (subtype == VSLENGTH) {
732 				for (;*val; val++)
733 					if (!localeisutf8 ||
734 					    (*val & 0xC0) != 0x80)
735 						varlen++;
736 			}
737 			else {
738 				if (quotes)
739 					STPUTS_QUOTES(val, syntax, expdest);
740 				else
741 					STPUTS(val, expdest);
742 
743 			}
744 		}
745 	}
746 
747 	if (subtype == VSPLUS)
748 		set = ! set;
749 
750 	easy = ((varflags & VSQUOTE) == 0 ||
751 		(*var == '@' && shellparam.nparam != 1));
752 
753 
754 	switch (subtype) {
755 	case VSLENGTH:
756 		expdest = cvtnum(varlen, expdest);
757 		goto record;
758 
759 	case VSNORMAL:
760 		if (!easy)
761 			break;
762 record:
763 		recordregion(startloc, expdest - stackblock(),
764 		    varflags & VSQUOTE || (ifsset() && ifsval()[0] == '\0' &&
765 		    (*var == '@' || *var == '*')));
766 		break;
767 
768 	case VSPLUS:
769 	case VSMINUS:
770 		if (!set) {
771 			argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
772 			    (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
773 			break;
774 		}
775 		if (easy)
776 			goto record;
777 		break;
778 
779 	case VSTRIMLEFT:
780 	case VSTRIMLEFTMAX:
781 	case VSTRIMRIGHT:
782 	case VSTRIMRIGHTMAX:
783 		if (!set)
784 			break;
785 		/*
786 		 * Terminate the string and start recording the pattern
787 		 * right after it
788 		 */
789 		STPUTC('\0', expdest);
790 		patloc = expdest - stackblock();
791 		if (subevalvar(p, NULL, patloc, subtype,
792 		    startloc, varflags, quotes) == 0) {
793 			int amount = (expdest - stackblock() - patloc) + 1;
794 			STADJUST(-amount, expdest);
795 		}
796 		/* Remove any recorded regions beyond start of variable */
797 		removerecordregions(startloc);
798 		goto record;
799 
800 	case VSASSIGN:
801 	case VSQUESTION:
802 		if (!set) {
803 			if (subevalvar(p, var, 0, subtype, startloc, varflags,
804 			    quotes)) {
805 				varflags &= ~VSNUL;
806 				/*
807 				 * Remove any recorded regions beyond
808 				 * start of variable
809 				 */
810 				removerecordregions(startloc);
811 				goto again;
812 			}
813 			break;
814 		}
815 		if (easy)
816 			goto record;
817 		break;
818 
819 	case VSERROR:
820 		c = p - var - 1;
821 		error("${%.*s%s}: Bad substitution", c, var,
822 		    (c > 0 && *p != CTLENDVAR) ? "..." : "");
823 
824 	default:
825 		abort();
826 	}
827 	p[-1] = '=';	/* recover overwritten '=' */
828 
829 	if (subtype != VSNORMAL) {	/* skip to end of alternative */
830 		int nesting = 1;
831 		for (;;) {
832 			if ((c = *p++) == CTLESC)
833 				p++;
834 			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
835 				if (set)
836 					argbackq = argbackq->next;
837 			} else if (c == CTLVAR) {
838 				if ((*p++ & VSTYPE) != VSNORMAL)
839 					nesting++;
840 			} else if (c == CTLENDVAR) {
841 				if (--nesting == 0)
842 					break;
843 			}
844 		}
845 	}
846 	return p;
847 }
848 
849 
850 
851 /*
852  * Test whether a specialized variable is set.
853  */
854 
855 static int
856 varisset(char *name, int nulok)
857 {
858 
859 	if (*name == '!')
860 		return backgndpidset();
861 	else if (*name == '@' || *name == '*') {
862 		if (*shellparam.p == NULL)
863 			return 0;
864 
865 		if (nulok) {
866 			char **av;
867 
868 			for (av = shellparam.p; *av; av++)
869 				if (**av != '\0')
870 					return 1;
871 			return 0;
872 		}
873 	} else if (is_digit(*name)) {
874 		char *ap;
875 		int num = atoi(name);
876 
877 		if (num > shellparam.nparam)
878 			return 0;
879 
880 		if (num == 0)
881 			ap = arg0;
882 		else
883 			ap = shellparam.p[num - 1];
884 
885 		if (nulok && (ap == NULL || *ap == '\0'))
886 			return 0;
887 	}
888 	return 1;
889 }
890 
891 static void
892 strtodest(const char *p, int flag, int subtype, int quoted)
893 {
894 	if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
895 		STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
896 	else
897 		STPUTS(p, expdest);
898 }
899 
900 /*
901  * Add the value of a specialized variable to the stack string.
902  */
903 
904 static void
905 varvalue(char *name, int quoted, int subtype, int flag)
906 {
907 	int num;
908 	char *p;
909 	int i;
910 	char sep;
911 	char **ap;
912 
913 	switch (*name) {
914 	case '$':
915 		num = rootpid;
916 		goto numvar;
917 	case '?':
918 		num = oexitstatus;
919 		goto numvar;
920 	case '#':
921 		num = shellparam.nparam;
922 		goto numvar;
923 	case '!':
924 		num = backgndpidval();
925 numvar:
926 		expdest = cvtnum(num, expdest);
927 		break;
928 	case '-':
929 		for (i = 0 ; i < NOPTS ; i++) {
930 			if (optlist[i].val)
931 				STPUTC(optlist[i].letter, expdest);
932 		}
933 		break;
934 	case '@':
935 		if (flag & EXP_FULL && quoted) {
936 			for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
937 				strtodest(p, flag, subtype, quoted);
938 				if (*ap)
939 					STPUTC('\0', expdest);
940 			}
941 			break;
942 		}
943 		/* FALLTHROUGH */
944 	case '*':
945 		if (ifsset())
946 			sep = ifsval()[0];
947 		else
948 			sep = ' ';
949 		for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
950 			strtodest(p, flag, subtype, quoted);
951 			if (!*ap)
952 				break;
953 			if (sep || (flag & EXP_FULL && !quoted && **ap != '\0'))
954 				STPUTC(sep, expdest);
955 		}
956 		break;
957 	case '0':
958 		p = arg0;
959 		strtodest(p, flag, subtype, quoted);
960 		break;
961 	default:
962 		if (is_digit(*name)) {
963 			num = atoi(name);
964 			if (num > 0 && num <= shellparam.nparam) {
965 				p = shellparam.p[num - 1];
966 				strtodest(p, flag, subtype, quoted);
967 			}
968 		}
969 		break;
970 	}
971 }
972 
973 
974 
975 /*
976  * Record the fact that we have to scan this region of the
977  * string for IFS characters.
978  */
979 
980 static void
981 recordregion(int start, int end, int inquotes)
982 {
983 	struct ifsregion *ifsp;
984 
985 	if (ifslastp == NULL) {
986 		ifsp = &ifsfirst;
987 	} else {
988 		if (ifslastp->endoff == start
989 		    && ifslastp->inquotes == inquotes) {
990 			/* extend previous area */
991 			ifslastp->endoff = end;
992 			return;
993 		}
994 		ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
995 		ifslastp->next = ifsp;
996 	}
997 	ifslastp = ifsp;
998 	ifslastp->next = NULL;
999 	ifslastp->begoff = start;
1000 	ifslastp->endoff = end;
1001 	ifslastp->inquotes = inquotes;
1002 }
1003 
1004 
1005 
1006 /*
1007  * Break the argument string into pieces based upon IFS and add the
1008  * strings to the argument list.  The regions of the string to be
1009  * searched for IFS characters have been stored by recordregion.
1010  * CTLESC characters are preserved but have little effect in this pass
1011  * other than escaping CTL* characters.  In particular, they do not escape
1012  * IFS characters: that should be done with the ifsregion mechanism.
1013  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
1014  * This pass treats them as a regular character, making the string non-empty.
1015  * Later, they are removed along with the other CTL* characters.
1016  */
1017 static void
1018 ifsbreakup(char *string, struct arglist *arglist)
1019 {
1020 	struct ifsregion *ifsp;
1021 	struct strlist *sp;
1022 	char *start;
1023 	char *p;
1024 	char *q;
1025 	const char *ifs;
1026 	const char *ifsspc;
1027 	int had_param_ch = 0;
1028 
1029 	start = string;
1030 
1031 	if (ifslastp == NULL) {
1032 		/* Return entire argument, IFS doesn't apply to any of it */
1033 		sp = (struct strlist *)stalloc(sizeof *sp);
1034 		sp->text = start;
1035 		*arglist->lastp = sp;
1036 		arglist->lastp = &sp->next;
1037 		return;
1038 	}
1039 
1040 	ifs = ifsset() ? ifsval() : " \t\n";
1041 
1042 	for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1043 		p = string + ifsp->begoff;
1044 		while (p < string + ifsp->endoff) {
1045 			q = p;
1046 			if (*p == CTLESC)
1047 				p++;
1048 			if (ifsp->inquotes) {
1049 				/* Only NULs (should be from "$@") end args */
1050 				had_param_ch = 1;
1051 				if (*p != 0) {
1052 					p++;
1053 					continue;
1054 				}
1055 				ifsspc = NULL;
1056 			} else {
1057 				if (!strchr(ifs, *p)) {
1058 					had_param_ch = 1;
1059 					p++;
1060 					continue;
1061 				}
1062 				ifsspc = strchr(" \t\n", *p);
1063 
1064 				/* Ignore IFS whitespace at start */
1065 				if (q == start && ifsspc != NULL) {
1066 					p++;
1067 					start = p;
1068 					continue;
1069 				}
1070 				had_param_ch = 0;
1071 			}
1072 
1073 			/* Save this argument... */
1074 			*q = '\0';
1075 			sp = (struct strlist *)stalloc(sizeof *sp);
1076 			sp->text = start;
1077 			*arglist->lastp = sp;
1078 			arglist->lastp = &sp->next;
1079 			p++;
1080 
1081 			if (ifsspc != NULL) {
1082 				/* Ignore further trailing IFS whitespace */
1083 				for (; p < string + ifsp->endoff; p++) {
1084 					q = p;
1085 					if (*p == CTLESC)
1086 						p++;
1087 					if (strchr(ifs, *p) == NULL) {
1088 						p = q;
1089 						break;
1090 					}
1091 					if (strchr(" \t\n", *p) == NULL) {
1092 						p++;
1093 						break;
1094 					}
1095 				}
1096 			}
1097 			start = p;
1098 		}
1099 	}
1100 
1101 	/*
1102 	 * Save anything left as an argument.
1103 	 * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1104 	 * generating 2 arguments, the second of which is empty.
1105 	 * Some recent clarification of the Posix spec say that it
1106 	 * should only generate one....
1107 	 */
1108 	if (had_param_ch || *start != 0) {
1109 		sp = (struct strlist *)stalloc(sizeof *sp);
1110 		sp->text = start;
1111 		*arglist->lastp = sp;
1112 		arglist->lastp = &sp->next;
1113 	}
1114 }
1115 
1116 
1117 static char expdir[PATH_MAX];
1118 #define expdir_end (expdir + sizeof(expdir))
1119 
1120 /*
1121  * Perform pathname generation and remove control characters.
1122  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1123  * The results are stored in the list exparg.
1124  */
1125 static void
1126 expandmeta(struct strlist *str, int flag __unused)
1127 {
1128 	char *p;
1129 	struct strlist **savelastp;
1130 	struct strlist *sp;
1131 	char c;
1132 	/* TODO - EXP_REDIR */
1133 
1134 	while (str) {
1135 		if (fflag)
1136 			goto nometa;
1137 		p = str->text;
1138 		for (;;) {			/* fast check for meta chars */
1139 			if ((c = *p++) == '\0')
1140 				goto nometa;
1141 			if (c == '*' || c == '?' || c == '[')
1142 				break;
1143 		}
1144 		savelastp = exparg.lastp;
1145 		INTOFF;
1146 		expmeta(expdir, str->text);
1147 		INTON;
1148 		if (exparg.lastp == savelastp) {
1149 			/*
1150 			 * no matches
1151 			 */
1152 nometa:
1153 			*exparg.lastp = str;
1154 			rmescapes(str->text);
1155 			exparg.lastp = &str->next;
1156 		} else {
1157 			*exparg.lastp = NULL;
1158 			*savelastp = sp = expsort(*savelastp);
1159 			while (sp->next != NULL)
1160 				sp = sp->next;
1161 			exparg.lastp = &sp->next;
1162 		}
1163 		str = str->next;
1164 	}
1165 }
1166 
1167 
1168 /*
1169  * Do metacharacter (i.e. *, ?, [...]) expansion.
1170  */
1171 
1172 static void
1173 expmeta(char *enddir, char *name)
1174 {
1175 	char *p;
1176 	char *q;
1177 	char *start;
1178 	char *endname;
1179 	int metaflag;
1180 	struct stat statb;
1181 	DIR *dirp;
1182 	struct dirent *dp;
1183 	int atend;
1184 	int matchdot;
1185 	int esc;
1186 
1187 	metaflag = 0;
1188 	start = name;
1189 	for (p = name; esc = 0, *p; p += esc + 1) {
1190 		if (*p == '*' || *p == '?')
1191 			metaflag = 1;
1192 		else if (*p == '[') {
1193 			q = p + 1;
1194 			if (*q == '!' || *q == '^')
1195 				q++;
1196 			for (;;) {
1197 				while (*q == CTLQUOTEMARK)
1198 					q++;
1199 				if (*q == CTLESC)
1200 					q++;
1201 				if (*q == '/' || *q == '\0')
1202 					break;
1203 				if (*++q == ']') {
1204 					metaflag = 1;
1205 					break;
1206 				}
1207 			}
1208 		} else if (*p == '\0')
1209 			break;
1210 		else if (*p == CTLQUOTEMARK)
1211 			continue;
1212 		else {
1213 			if (*p == CTLESC)
1214 				esc++;
1215 			if (p[esc] == '/') {
1216 				if (metaflag)
1217 					break;
1218 				start = p + esc + 1;
1219 			}
1220 		}
1221 	}
1222 	if (metaflag == 0) {	/* we've reached the end of the file name */
1223 		if (enddir != expdir)
1224 			metaflag++;
1225 		for (p = name ; ; p++) {
1226 			if (*p == CTLQUOTEMARK)
1227 				continue;
1228 			if (*p == CTLESC)
1229 				p++;
1230 			*enddir++ = *p;
1231 			if (*p == '\0')
1232 				break;
1233 			if (enddir == expdir_end)
1234 				return;
1235 		}
1236 		if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1237 			addfname(expdir);
1238 		return;
1239 	}
1240 	endname = p;
1241 	if (start != name) {
1242 		p = name;
1243 		while (p < start) {
1244 			while (*p == CTLQUOTEMARK)
1245 				p++;
1246 			if (*p == CTLESC)
1247 				p++;
1248 			*enddir++ = *p++;
1249 			if (enddir == expdir_end)
1250 				return;
1251 		}
1252 	}
1253 	if (enddir == expdir) {
1254 		p = ".";
1255 	} else if (enddir == expdir + 1 && *expdir == '/') {
1256 		p = "/";
1257 	} else {
1258 		p = expdir;
1259 		enddir[-1] = '\0';
1260 	}
1261 	if ((dirp = opendir(p)) == NULL)
1262 		return;
1263 	if (enddir != expdir)
1264 		enddir[-1] = '/';
1265 	if (*endname == 0) {
1266 		atend = 1;
1267 	} else {
1268 		atend = 0;
1269 		*endname = '\0';
1270 		endname += esc + 1;
1271 	}
1272 	matchdot = 0;
1273 	p = start;
1274 	while (*p == CTLQUOTEMARK)
1275 		p++;
1276 	if (*p == CTLESC)
1277 		p++;
1278 	if (*p == '.')
1279 		matchdot++;
1280 	while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1281 		if (dp->d_name[0] == '.' && ! matchdot)
1282 			continue;
1283 		if (patmatch(start, dp->d_name, 0)) {
1284 			if (enddir + dp->d_namlen + 1 > expdir_end)
1285 				continue;
1286 			memcpy(enddir, dp->d_name, dp->d_namlen + 1);
1287 			if (atend)
1288 				addfname(expdir);
1289 			else {
1290 				if (enddir + dp->d_namlen + 2 > expdir_end)
1291 					continue;
1292 				enddir[dp->d_namlen] = '/';
1293 				enddir[dp->d_namlen + 1] = '\0';
1294 				expmeta(enddir + dp->d_namlen + 1, endname);
1295 			}
1296 		}
1297 	}
1298 	closedir(dirp);
1299 	if (! atend)
1300 		endname[-esc - 1] = esc ? CTLESC : '/';
1301 }
1302 
1303 
1304 /*
1305  * Add a file name to the list.
1306  */
1307 
1308 static void
1309 addfname(char *name)
1310 {
1311 	char *p;
1312 	struct strlist *sp;
1313 
1314 	p = stalloc(strlen(name) + 1);
1315 	scopy(name, p);
1316 	sp = (struct strlist *)stalloc(sizeof *sp);
1317 	sp->text = p;
1318 	*exparg.lastp = sp;
1319 	exparg.lastp = &sp->next;
1320 }
1321 
1322 
1323 /*
1324  * Sort the results of file name expansion.  It calculates the number of
1325  * strings to sort and then calls msort (short for merge sort) to do the
1326  * work.
1327  */
1328 
1329 static struct strlist *
1330 expsort(struct strlist *str)
1331 {
1332 	int len;
1333 	struct strlist *sp;
1334 
1335 	len = 0;
1336 	for (sp = str ; sp ; sp = sp->next)
1337 		len++;
1338 	return msort(str, len);
1339 }
1340 
1341 
1342 static struct strlist *
1343 msort(struct strlist *list, int len)
1344 {
1345 	struct strlist *p, *q = NULL;
1346 	struct strlist **lpp;
1347 	int half;
1348 	int n;
1349 
1350 	if (len <= 1)
1351 		return list;
1352 	half = len >> 1;
1353 	p = list;
1354 	for (n = half ; --n >= 0 ; ) {
1355 		q = p;
1356 		p = p->next;
1357 	}
1358 	q->next = NULL;			/* terminate first half of list */
1359 	q = msort(list, half);		/* sort first half of list */
1360 	p = msort(p, len - half);		/* sort second half */
1361 	lpp = &list;
1362 	for (;;) {
1363 		if (strcmp(p->text, q->text) < 0) {
1364 			*lpp = p;
1365 			lpp = &p->next;
1366 			if ((p = *lpp) == NULL) {
1367 				*lpp = q;
1368 				break;
1369 			}
1370 		} else {
1371 			*lpp = q;
1372 			lpp = &q->next;
1373 			if ((q = *lpp) == NULL) {
1374 				*lpp = p;
1375 				break;
1376 			}
1377 		}
1378 	}
1379 	return list;
1380 }
1381 
1382 
1383 
1384 static wchar_t
1385 get_wc(const char **p)
1386 {
1387 	wchar_t c;
1388 	int chrlen;
1389 
1390 	chrlen = mbtowc(&c, *p, 4);
1391 	if (chrlen == 0)
1392 		return 0;
1393 	else if (chrlen == -1)
1394 		c = 0;
1395 	else
1396 		*p += chrlen;
1397 	return c;
1398 }
1399 
1400 
1401 /*
1402  * Returns true if the pattern matches the string.
1403  */
1404 
1405 int
1406 patmatch(const char *pattern, const char *string, int squoted)
1407 {
1408 	const char *p, *q;
1409 	char c;
1410 	wchar_t wc, wc2;
1411 
1412 	p = pattern;
1413 	q = string;
1414 	for (;;) {
1415 		switch (c = *p++) {
1416 		case '\0':
1417 			goto breakloop;
1418 		case CTLESC:
1419 			if (squoted && *q == CTLESC)
1420 				q++;
1421 			if (*q++ != *p++)
1422 				return 0;
1423 			break;
1424 		case CTLQUOTEMARK:
1425 			continue;
1426 		case '?':
1427 			if (squoted && *q == CTLESC)
1428 				q++;
1429 			if (localeisutf8)
1430 				wc = get_wc(&q);
1431 			else
1432 				wc = *q++;
1433 			if (wc == '\0')
1434 				return 0;
1435 			break;
1436 		case '*':
1437 			c = *p;
1438 			while (c == CTLQUOTEMARK || c == '*')
1439 				c = *++p;
1440 			if (c != CTLESC &&  c != CTLQUOTEMARK &&
1441 			    c != '?' && c != '*' && c != '[') {
1442 				while (*q != c) {
1443 					if (squoted && *q == CTLESC &&
1444 					    q[1] == c)
1445 						break;
1446 					if (*q == '\0')
1447 						return 0;
1448 					if (squoted && *q == CTLESC)
1449 						q++;
1450 					q++;
1451 				}
1452 			}
1453 			do {
1454 				if (patmatch(p, q, squoted))
1455 					return 1;
1456 				if (squoted && *q == CTLESC)
1457 					q++;
1458 			} while (*q++ != '\0');
1459 			return 0;
1460 		case '[': {
1461 			const char *endp;
1462 			int invert, found;
1463 			wchar_t chr;
1464 
1465 			endp = p;
1466 			if (*endp == '!' || *endp == '^')
1467 				endp++;
1468 			for (;;) {
1469 				while (*endp == CTLQUOTEMARK)
1470 					endp++;
1471 				if (*endp == '\0')
1472 					goto dft;		/* no matching ] */
1473 				if (*endp == CTLESC)
1474 					endp++;
1475 				if (*++endp == ']')
1476 					break;
1477 			}
1478 			invert = 0;
1479 			if (*p == '!' || *p == '^') {
1480 				invert++;
1481 				p++;
1482 			}
1483 			found = 0;
1484 			if (squoted && *q == CTLESC)
1485 				q++;
1486 			if (localeisutf8)
1487 				chr = get_wc(&q);
1488 			else
1489 				chr = *q++;
1490 			if (chr == '\0')
1491 				return 0;
1492 			c = *p++;
1493 			do {
1494 				if (c == CTLQUOTEMARK)
1495 					continue;
1496 				if (c == CTLESC)
1497 					c = *p++;
1498 				if (localeisutf8 && c & 0x80) {
1499 					p--;
1500 					wc = get_wc(&p);
1501 					if (wc == 0) /* bad utf-8 */
1502 						return 0;
1503 				} else
1504 					wc = c;
1505 				if (*p == '-' && p[1] != ']') {
1506 					p++;
1507 					while (*p == CTLQUOTEMARK)
1508 						p++;
1509 					if (*p == CTLESC)
1510 						p++;
1511 					if (localeisutf8) {
1512 						wc2 = get_wc(&p);
1513 						if (wc2 == 0) /* bad utf-8 */
1514 							return 0;
1515 					} else
1516 						wc2 = *p++;
1517 					if (   collate_range_cmp(chr, wc) >= 0
1518 					    && collate_range_cmp(chr, wc2) <= 0
1519 					   )
1520 						found = 1;
1521 				} else {
1522 					if (chr == wc)
1523 						found = 1;
1524 				}
1525 			} while ((c = *p++) != ']');
1526 			if (found == invert)
1527 				return 0;
1528 			break;
1529 		}
1530 dft:	        default:
1531 			if (squoted && *q == CTLESC)
1532 				q++;
1533 			if (*q++ != c)
1534 				return 0;
1535 			break;
1536 		}
1537 	}
1538 breakloop:
1539 	if (*q != '\0')
1540 		return 0;
1541 	return 1;
1542 }
1543 
1544 
1545 
1546 /*
1547  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1548  */
1549 
1550 void
1551 rmescapes(char *str)
1552 {
1553 	char *p, *q;
1554 
1555 	p = str;
1556 	while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
1557 		if (*p++ == '\0')
1558 			return;
1559 	}
1560 	q = p;
1561 	while (*p) {
1562 		if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
1563 			p++;
1564 			continue;
1565 		}
1566 		if (*p == CTLESC)
1567 			p++;
1568 		*q++ = *p++;
1569 	}
1570 	*q = '\0';
1571 }
1572 
1573 
1574 
1575 /*
1576  * See if a pattern matches in a case statement.
1577  */
1578 
1579 int
1580 casematch(union node *pattern, const char *val)
1581 {
1582 	struct stackmark smark;
1583 	int result;
1584 	char *p;
1585 
1586 	setstackmark(&smark);
1587 	argbackq = pattern->narg.backquote;
1588 	STARTSTACKSTR(expdest);
1589 	ifslastp = NULL;
1590 	argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1591 	STPUTC('\0', expdest);
1592 	p = grabstackstr(expdest);
1593 	result = patmatch(p, val, 0);
1594 	popstackmark(&smark);
1595 	return result;
1596 }
1597 
1598 /*
1599  * Our own itoa().
1600  */
1601 
1602 static char *
1603 cvtnum(int num, char *buf)
1604 {
1605 	char temp[32];
1606 	int neg = num < 0;
1607 	char *p = temp + 31;
1608 
1609 	temp[31] = '\0';
1610 
1611 	do {
1612 		*--p = num % 10 + '0';
1613 	} while ((num /= 10) != 0);
1614 
1615 	if (neg)
1616 		*--p = '-';
1617 
1618 	STPUTS(p, buf);
1619 	return buf;
1620 }
1621 
1622 /*
1623  * Check statically if expanding a string may have side effects.
1624  */
1625 int
1626 expandhassideeffects(const char *p)
1627 {
1628 	int c;
1629 	int arinest;
1630 
1631 	arinest = 0;
1632 	while ((c = *p++) != '\0') {
1633 		switch (c) {
1634 		case CTLESC:
1635 			p++;
1636 			break;
1637 		case CTLVAR:
1638 			c = *p++;
1639 			/* Expanding $! sets the job to remembered. */
1640 			if (*p == '!')
1641 				return 1;
1642 			if ((c & VSTYPE) == VSASSIGN)
1643 				return 1;
1644 			/*
1645 			 * If we are in arithmetic, the parameter may contain
1646 			 * '=' which may cause side effects. Exceptions are
1647 			 * the length of a parameter and $$, $# and $? which
1648 			 * are always numeric.
1649 			 */
1650 			if ((c & VSTYPE) == VSLENGTH) {
1651 				while (*p != '=')
1652 					p++;
1653 				p++;
1654 				break;
1655 			}
1656 			if ((*p == '$' || *p == '#' || *p == '?') &&
1657 			    p[1] == '=') {
1658 				p += 2;
1659 				break;
1660 			}
1661 			if (arinest > 0)
1662 				return 1;
1663 			break;
1664 		case CTLBACKQ:
1665 		case CTLBACKQ | CTLQUOTE:
1666 			if (arinest > 0)
1667 				return 1;
1668 			break;
1669 		case CTLARI:
1670 			arinest++;
1671 			break;
1672 		case CTLENDARI:
1673 			arinest--;
1674 			break;
1675 		case '=':
1676 			if (*p == '=') {
1677 				/* Allow '==' operator. */
1678 				p++;
1679 				continue;
1680 			}
1681 			if (arinest > 0)
1682 				return 1;
1683 			break;
1684 		case '!': case '<': case '>':
1685 			/* Allow '!=', '<=', '>=' operators. */
1686 			if (*p == '=')
1687 				p++;
1688 			break;
1689 		}
1690 	}
1691 	return 0;
1692 }
1693 
1694 /*
1695  * Do most of the work for wordexp(3).
1696  */
1697 
1698 int
1699 wordexpcmd(int argc, char **argv)
1700 {
1701 	size_t len;
1702 	int i;
1703 
1704 	out1fmt("%08x", argc - 1);
1705 	for (i = 1, len = 0; i < argc; i++)
1706 		len += strlen(argv[i]);
1707 	out1fmt("%08x", (int)len);
1708 	for (i = 1; i < argc; i++)
1709 		outbin(argv[i], strlen(argv[i]) + 1, out1);
1710         return (0);
1711 }
1712