xref: /freebsd/bin/sh/expand.c (revision 59c7ad52aaa5b26e503871334672af0f58f9c2e8)
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);
765 		break;
766 
767 	case VSPLUS:
768 	case VSMINUS:
769 		if (!set) {
770 			argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
771 			    (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
772 			break;
773 		}
774 		if (easy)
775 			goto record;
776 		break;
777 
778 	case VSTRIMLEFT:
779 	case VSTRIMLEFTMAX:
780 	case VSTRIMRIGHT:
781 	case VSTRIMRIGHTMAX:
782 		if (!set)
783 			break;
784 		/*
785 		 * Terminate the string and start recording the pattern
786 		 * right after it
787 		 */
788 		STPUTC('\0', expdest);
789 		patloc = expdest - stackblock();
790 		if (subevalvar(p, NULL, patloc, subtype,
791 		    startloc, varflags, quotes) == 0) {
792 			int amount = (expdest - stackblock() - patloc) + 1;
793 			STADJUST(-amount, expdest);
794 		}
795 		/* Remove any recorded regions beyond start of variable */
796 		removerecordregions(startloc);
797 		goto record;
798 
799 	case VSASSIGN:
800 	case VSQUESTION:
801 		if (!set) {
802 			if (subevalvar(p, var, 0, subtype, startloc, varflags,
803 			    quotes)) {
804 				varflags &= ~VSNUL;
805 				/*
806 				 * Remove any recorded regions beyond
807 				 * start of variable
808 				 */
809 				removerecordregions(startloc);
810 				goto again;
811 			}
812 			break;
813 		}
814 		if (easy)
815 			goto record;
816 		break;
817 
818 	case VSERROR:
819 		c = p - var - 1;
820 		error("${%.*s%s}: Bad substitution", c, var,
821 		    (c > 0 && *p != CTLENDVAR) ? "..." : "");
822 
823 	default:
824 		abort();
825 	}
826 	p[-1] = '=';	/* recover overwritten '=' */
827 
828 	if (subtype != VSNORMAL) {	/* skip to end of alternative */
829 		int nesting = 1;
830 		for (;;) {
831 			if ((c = *p++) == CTLESC)
832 				p++;
833 			else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
834 				if (set)
835 					argbackq = argbackq->next;
836 			} else if (c == CTLVAR) {
837 				if ((*p++ & VSTYPE) != VSNORMAL)
838 					nesting++;
839 			} else if (c == CTLENDVAR) {
840 				if (--nesting == 0)
841 					break;
842 			}
843 		}
844 	}
845 	return p;
846 }
847 
848 
849 
850 /*
851  * Test whether a specialized variable is set.
852  */
853 
854 static int
855 varisset(char *name, int nulok)
856 {
857 
858 	if (*name == '!')
859 		return backgndpidset();
860 	else if (*name == '@' || *name == '*') {
861 		if (*shellparam.p == NULL)
862 			return 0;
863 
864 		if (nulok) {
865 			char **av;
866 
867 			for (av = shellparam.p; *av; av++)
868 				if (**av != '\0')
869 					return 1;
870 			return 0;
871 		}
872 	} else if (is_digit(*name)) {
873 		char *ap;
874 		int num = atoi(name);
875 
876 		if (num > shellparam.nparam)
877 			return 0;
878 
879 		if (num == 0)
880 			ap = arg0;
881 		else
882 			ap = shellparam.p[num - 1];
883 
884 		if (nulok && (ap == NULL || *ap == '\0'))
885 			return 0;
886 	}
887 	return 1;
888 }
889 
890 static void
891 strtodest(const char *p, int flag, int subtype, int quoted)
892 {
893 	if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
894 		STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
895 	else
896 		STPUTS(p, expdest);
897 }
898 
899 /*
900  * Add the value of a specialized variable to the stack string.
901  */
902 
903 static void
904 varvalue(char *name, int quoted, int subtype, int flag)
905 {
906 	int num;
907 	char *p;
908 	int i;
909 	char sep;
910 	char **ap;
911 
912 	switch (*name) {
913 	case '$':
914 		num = rootpid;
915 		goto numvar;
916 	case '?':
917 		num = oexitstatus;
918 		goto numvar;
919 	case '#':
920 		num = shellparam.nparam;
921 		goto numvar;
922 	case '!':
923 		num = backgndpidval();
924 numvar:
925 		expdest = cvtnum(num, expdest);
926 		break;
927 	case '-':
928 		for (i = 0 ; i < NOPTS ; i++) {
929 			if (optlist[i].val)
930 				STPUTC(optlist[i].letter, expdest);
931 		}
932 		break;
933 	case '@':
934 		if (flag & EXP_FULL && quoted) {
935 			for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
936 				strtodest(p, flag, subtype, quoted);
937 				if (*ap)
938 					STPUTC('\0', expdest);
939 			}
940 			break;
941 		}
942 		/* FALLTHROUGH */
943 	case '*':
944 		if (ifsset())
945 			sep = ifsval()[0];
946 		else
947 			sep = ' ';
948 		for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
949 			strtodest(p, flag, subtype, quoted);
950 			if (*ap && sep)
951 				STPUTC(sep, expdest);
952 		}
953 		break;
954 	case '0':
955 		p = arg0;
956 		strtodest(p, flag, subtype, quoted);
957 		break;
958 	default:
959 		if (is_digit(*name)) {
960 			num = atoi(name);
961 			if (num > 0 && num <= shellparam.nparam) {
962 				p = shellparam.p[num - 1];
963 				strtodest(p, flag, subtype, quoted);
964 			}
965 		}
966 		break;
967 	}
968 }
969 
970 
971 
972 /*
973  * Record the fact that we have to scan this region of the
974  * string for IFS characters.
975  */
976 
977 static void
978 recordregion(int start, int end, int inquotes)
979 {
980 	struct ifsregion *ifsp;
981 
982 	if (ifslastp == NULL) {
983 		ifsp = &ifsfirst;
984 	} else {
985 		if (ifslastp->endoff == start
986 		    && ifslastp->inquotes == inquotes) {
987 			/* extend previous area */
988 			ifslastp->endoff = end;
989 			return;
990 		}
991 		ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
992 		ifslastp->next = ifsp;
993 	}
994 	ifslastp = ifsp;
995 	ifslastp->next = NULL;
996 	ifslastp->begoff = start;
997 	ifslastp->endoff = end;
998 	ifslastp->inquotes = inquotes;
999 }
1000 
1001 
1002 
1003 /*
1004  * Break the argument string into pieces based upon IFS and add the
1005  * strings to the argument list.  The regions of the string to be
1006  * searched for IFS characters have been stored by recordregion.
1007  * CTLESC characters are preserved but have little effect in this pass
1008  * other than escaping CTL* characters.  In particular, they do not escape
1009  * IFS characters: that should be done with the ifsregion mechanism.
1010  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
1011  * This pass treats them as a regular character, making the string non-empty.
1012  * Later, they are removed along with the other CTL* characters.
1013  */
1014 static void
1015 ifsbreakup(char *string, struct arglist *arglist)
1016 {
1017 	struct ifsregion *ifsp;
1018 	struct strlist *sp;
1019 	char *start;
1020 	char *p;
1021 	char *q;
1022 	const char *ifs;
1023 	const char *ifsspc;
1024 	int had_param_ch = 0;
1025 
1026 	start = string;
1027 
1028 	if (ifslastp == NULL) {
1029 		/* Return entire argument, IFS doesn't apply to any of it */
1030 		sp = (struct strlist *)stalloc(sizeof *sp);
1031 		sp->text = start;
1032 		*arglist->lastp = sp;
1033 		arglist->lastp = &sp->next;
1034 		return;
1035 	}
1036 
1037 	ifs = ifsset() ? ifsval() : " \t\n";
1038 
1039 	for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1040 		p = string + ifsp->begoff;
1041 		while (p < string + ifsp->endoff) {
1042 			q = p;
1043 			if (*p == CTLESC)
1044 				p++;
1045 			if (ifsp->inquotes) {
1046 				/* Only NULs (should be from "$@") end args */
1047 				had_param_ch = 1;
1048 				if (*p != 0) {
1049 					p++;
1050 					continue;
1051 				}
1052 				ifsspc = NULL;
1053 			} else {
1054 				if (!strchr(ifs, *p)) {
1055 					had_param_ch = 1;
1056 					p++;
1057 					continue;
1058 				}
1059 				ifsspc = strchr(" \t\n", *p);
1060 
1061 				/* Ignore IFS whitespace at start */
1062 				if (q == start && ifsspc != NULL) {
1063 					p++;
1064 					start = p;
1065 					continue;
1066 				}
1067 				had_param_ch = 0;
1068 			}
1069 
1070 			/* Save this argument... */
1071 			*q = '\0';
1072 			sp = (struct strlist *)stalloc(sizeof *sp);
1073 			sp->text = start;
1074 			*arglist->lastp = sp;
1075 			arglist->lastp = &sp->next;
1076 			p++;
1077 
1078 			if (ifsspc != NULL) {
1079 				/* Ignore further trailing IFS whitespace */
1080 				for (; p < string + ifsp->endoff; p++) {
1081 					q = p;
1082 					if (*p == CTLESC)
1083 						p++;
1084 					if (strchr(ifs, *p) == NULL) {
1085 						p = q;
1086 						break;
1087 					}
1088 					if (strchr(" \t\n", *p) == NULL) {
1089 						p++;
1090 						break;
1091 					}
1092 				}
1093 			}
1094 			start = p;
1095 		}
1096 	}
1097 
1098 	/*
1099 	 * Save anything left as an argument.
1100 	 * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1101 	 * generating 2 arguments, the second of which is empty.
1102 	 * Some recent clarification of the Posix spec say that it
1103 	 * should only generate one....
1104 	 */
1105 	if (had_param_ch || *start != 0) {
1106 		sp = (struct strlist *)stalloc(sizeof *sp);
1107 		sp->text = start;
1108 		*arglist->lastp = sp;
1109 		arglist->lastp = &sp->next;
1110 	}
1111 }
1112 
1113 
1114 static char expdir[PATH_MAX];
1115 #define expdir_end (expdir + sizeof(expdir))
1116 
1117 /*
1118  * Perform pathname generation and remove control characters.
1119  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1120  * The results are stored in the list exparg.
1121  */
1122 static void
1123 expandmeta(struct strlist *str, int flag __unused)
1124 {
1125 	char *p;
1126 	struct strlist **savelastp;
1127 	struct strlist *sp;
1128 	char c;
1129 	/* TODO - EXP_REDIR */
1130 
1131 	while (str) {
1132 		if (fflag)
1133 			goto nometa;
1134 		p = str->text;
1135 		for (;;) {			/* fast check for meta chars */
1136 			if ((c = *p++) == '\0')
1137 				goto nometa;
1138 			if (c == '*' || c == '?' || c == '[')
1139 				break;
1140 		}
1141 		savelastp = exparg.lastp;
1142 		INTOFF;
1143 		expmeta(expdir, str->text);
1144 		INTON;
1145 		if (exparg.lastp == savelastp) {
1146 			/*
1147 			 * no matches
1148 			 */
1149 nometa:
1150 			*exparg.lastp = str;
1151 			rmescapes(str->text);
1152 			exparg.lastp = &str->next;
1153 		} else {
1154 			*exparg.lastp = NULL;
1155 			*savelastp = sp = expsort(*savelastp);
1156 			while (sp->next != NULL)
1157 				sp = sp->next;
1158 			exparg.lastp = &sp->next;
1159 		}
1160 		str = str->next;
1161 	}
1162 }
1163 
1164 
1165 /*
1166  * Do metacharacter (i.e. *, ?, [...]) expansion.
1167  */
1168 
1169 static void
1170 expmeta(char *enddir, char *name)
1171 {
1172 	char *p;
1173 	char *q;
1174 	char *start;
1175 	char *endname;
1176 	int metaflag;
1177 	struct stat statb;
1178 	DIR *dirp;
1179 	struct dirent *dp;
1180 	int atend;
1181 	int matchdot;
1182 	int esc;
1183 
1184 	metaflag = 0;
1185 	start = name;
1186 	for (p = name; esc = 0, *p; p += esc + 1) {
1187 		if (*p == '*' || *p == '?')
1188 			metaflag = 1;
1189 		else if (*p == '[') {
1190 			q = p + 1;
1191 			if (*q == '!' || *q == '^')
1192 				q++;
1193 			for (;;) {
1194 				while (*q == CTLQUOTEMARK)
1195 					q++;
1196 				if (*q == CTLESC)
1197 					q++;
1198 				if (*q == '/' || *q == '\0')
1199 					break;
1200 				if (*++q == ']') {
1201 					metaflag = 1;
1202 					break;
1203 				}
1204 			}
1205 		} else if (*p == '\0')
1206 			break;
1207 		else if (*p == CTLQUOTEMARK)
1208 			continue;
1209 		else {
1210 			if (*p == CTLESC)
1211 				esc++;
1212 			if (p[esc] == '/') {
1213 				if (metaflag)
1214 					break;
1215 				start = p + esc + 1;
1216 			}
1217 		}
1218 	}
1219 	if (metaflag == 0) {	/* we've reached the end of the file name */
1220 		if (enddir != expdir)
1221 			metaflag++;
1222 		for (p = name ; ; p++) {
1223 			if (*p == CTLQUOTEMARK)
1224 				continue;
1225 			if (*p == CTLESC)
1226 				p++;
1227 			*enddir++ = *p;
1228 			if (*p == '\0')
1229 				break;
1230 			if (enddir == expdir_end)
1231 				return;
1232 		}
1233 		if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1234 			addfname(expdir);
1235 		return;
1236 	}
1237 	endname = p;
1238 	if (start != name) {
1239 		p = name;
1240 		while (p < start) {
1241 			while (*p == CTLQUOTEMARK)
1242 				p++;
1243 			if (*p == CTLESC)
1244 				p++;
1245 			*enddir++ = *p++;
1246 			if (enddir == expdir_end)
1247 				return;
1248 		}
1249 	}
1250 	if (enddir == expdir) {
1251 		p = ".";
1252 	} else if (enddir == expdir + 1 && *expdir == '/') {
1253 		p = "/";
1254 	} else {
1255 		p = expdir;
1256 		enddir[-1] = '\0';
1257 	}
1258 	if ((dirp = opendir(p)) == NULL)
1259 		return;
1260 	if (enddir != expdir)
1261 		enddir[-1] = '/';
1262 	if (*endname == 0) {
1263 		atend = 1;
1264 	} else {
1265 		atend = 0;
1266 		*endname = '\0';
1267 		endname += esc + 1;
1268 	}
1269 	matchdot = 0;
1270 	p = start;
1271 	while (*p == CTLQUOTEMARK)
1272 		p++;
1273 	if (*p == CTLESC)
1274 		p++;
1275 	if (*p == '.')
1276 		matchdot++;
1277 	while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1278 		if (dp->d_name[0] == '.' && ! matchdot)
1279 			continue;
1280 		if (patmatch(start, dp->d_name, 0)) {
1281 			if (enddir + dp->d_namlen + 1 > expdir_end)
1282 				continue;
1283 			memcpy(enddir, dp->d_name, dp->d_namlen + 1);
1284 			if (atend)
1285 				addfname(expdir);
1286 			else {
1287 				if (enddir + dp->d_namlen + 2 > expdir_end)
1288 					continue;
1289 				enddir[dp->d_namlen] = '/';
1290 				enddir[dp->d_namlen + 1] = '\0';
1291 				expmeta(enddir + dp->d_namlen + 1, endname);
1292 			}
1293 		}
1294 	}
1295 	closedir(dirp);
1296 	if (! atend)
1297 		endname[-esc - 1] = esc ? CTLESC : '/';
1298 }
1299 
1300 
1301 /*
1302  * Add a file name to the list.
1303  */
1304 
1305 static void
1306 addfname(char *name)
1307 {
1308 	char *p;
1309 	struct strlist *sp;
1310 
1311 	p = stalloc(strlen(name) + 1);
1312 	scopy(name, p);
1313 	sp = (struct strlist *)stalloc(sizeof *sp);
1314 	sp->text = p;
1315 	*exparg.lastp = sp;
1316 	exparg.lastp = &sp->next;
1317 }
1318 
1319 
1320 /*
1321  * Sort the results of file name expansion.  It calculates the number of
1322  * strings to sort and then calls msort (short for merge sort) to do the
1323  * work.
1324  */
1325 
1326 static struct strlist *
1327 expsort(struct strlist *str)
1328 {
1329 	int len;
1330 	struct strlist *sp;
1331 
1332 	len = 0;
1333 	for (sp = str ; sp ; sp = sp->next)
1334 		len++;
1335 	return msort(str, len);
1336 }
1337 
1338 
1339 static struct strlist *
1340 msort(struct strlist *list, int len)
1341 {
1342 	struct strlist *p, *q = NULL;
1343 	struct strlist **lpp;
1344 	int half;
1345 	int n;
1346 
1347 	if (len <= 1)
1348 		return list;
1349 	half = len >> 1;
1350 	p = list;
1351 	for (n = half ; --n >= 0 ; ) {
1352 		q = p;
1353 		p = p->next;
1354 	}
1355 	q->next = NULL;			/* terminate first half of list */
1356 	q = msort(list, half);		/* sort first half of list */
1357 	p = msort(p, len - half);		/* sort second half */
1358 	lpp = &list;
1359 	for (;;) {
1360 		if (strcmp(p->text, q->text) < 0) {
1361 			*lpp = p;
1362 			lpp = &p->next;
1363 			if ((p = *lpp) == NULL) {
1364 				*lpp = q;
1365 				break;
1366 			}
1367 		} else {
1368 			*lpp = q;
1369 			lpp = &q->next;
1370 			if ((q = *lpp) == NULL) {
1371 				*lpp = p;
1372 				break;
1373 			}
1374 		}
1375 	}
1376 	return list;
1377 }
1378 
1379 
1380 
1381 static wchar_t
1382 get_wc(const char **p)
1383 {
1384 	wchar_t c;
1385 	int chrlen;
1386 
1387 	chrlen = mbtowc(&c, *p, 4);
1388 	if (chrlen == 0)
1389 		return 0;
1390 	else if (chrlen == -1)
1391 		c = 0;
1392 	else
1393 		*p += chrlen;
1394 	return c;
1395 }
1396 
1397 
1398 /*
1399  * Returns true if the pattern matches the string.
1400  */
1401 
1402 int
1403 patmatch(const char *pattern, const char *string, int squoted)
1404 {
1405 	const char *p, *q;
1406 	char c;
1407 	wchar_t wc, wc2;
1408 
1409 	p = pattern;
1410 	q = string;
1411 	for (;;) {
1412 		switch (c = *p++) {
1413 		case '\0':
1414 			goto breakloop;
1415 		case CTLESC:
1416 			if (squoted && *q == CTLESC)
1417 				q++;
1418 			if (*q++ != *p++)
1419 				return 0;
1420 			break;
1421 		case CTLQUOTEMARK:
1422 			continue;
1423 		case '?':
1424 			if (squoted && *q == CTLESC)
1425 				q++;
1426 			if (localeisutf8)
1427 				wc = get_wc(&q);
1428 			else
1429 				wc = *q++;
1430 			if (wc == '\0')
1431 				return 0;
1432 			break;
1433 		case '*':
1434 			c = *p;
1435 			while (c == CTLQUOTEMARK || c == '*')
1436 				c = *++p;
1437 			if (c != CTLESC &&  c != CTLQUOTEMARK &&
1438 			    c != '?' && c != '*' && c != '[') {
1439 				while (*q != c) {
1440 					if (squoted && *q == CTLESC &&
1441 					    q[1] == c)
1442 						break;
1443 					if (*q == '\0')
1444 						return 0;
1445 					if (squoted && *q == CTLESC)
1446 						q++;
1447 					q++;
1448 				}
1449 			}
1450 			do {
1451 				if (patmatch(p, q, squoted))
1452 					return 1;
1453 				if (squoted && *q == CTLESC)
1454 					q++;
1455 			} while (*q++ != '\0');
1456 			return 0;
1457 		case '[': {
1458 			const char *endp;
1459 			int invert, found;
1460 			wchar_t chr;
1461 
1462 			endp = p;
1463 			if (*endp == '!' || *endp == '^')
1464 				endp++;
1465 			for (;;) {
1466 				while (*endp == CTLQUOTEMARK)
1467 					endp++;
1468 				if (*endp == '\0')
1469 					goto dft;		/* no matching ] */
1470 				if (*endp == CTLESC)
1471 					endp++;
1472 				if (*++endp == ']')
1473 					break;
1474 			}
1475 			invert = 0;
1476 			if (*p == '!' || *p == '^') {
1477 				invert++;
1478 				p++;
1479 			}
1480 			found = 0;
1481 			if (squoted && *q == CTLESC)
1482 				q++;
1483 			if (localeisutf8)
1484 				chr = get_wc(&q);
1485 			else
1486 				chr = *q++;
1487 			if (chr == '\0')
1488 				return 0;
1489 			c = *p++;
1490 			do {
1491 				if (c == CTLQUOTEMARK)
1492 					continue;
1493 				if (c == CTLESC)
1494 					c = *p++;
1495 				if (localeisutf8 && c & 0x80) {
1496 					p--;
1497 					wc = get_wc(&p);
1498 					if (wc == 0) /* bad utf-8 */
1499 						return 0;
1500 				} else
1501 					wc = c;
1502 				if (*p == '-' && p[1] != ']') {
1503 					p++;
1504 					while (*p == CTLQUOTEMARK)
1505 						p++;
1506 					if (*p == CTLESC)
1507 						p++;
1508 					if (localeisutf8) {
1509 						wc2 = get_wc(&p);
1510 						if (wc2 == 0) /* bad utf-8 */
1511 							return 0;
1512 					} else
1513 						wc2 = *p++;
1514 					if (   collate_range_cmp(chr, wc) >= 0
1515 					    && collate_range_cmp(chr, wc2) <= 0
1516 					   )
1517 						found = 1;
1518 				} else {
1519 					if (chr == wc)
1520 						found = 1;
1521 				}
1522 			} while ((c = *p++) != ']');
1523 			if (found == invert)
1524 				return 0;
1525 			break;
1526 		}
1527 dft:	        default:
1528 			if (squoted && *q == CTLESC)
1529 				q++;
1530 			if (*q++ != c)
1531 				return 0;
1532 			break;
1533 		}
1534 	}
1535 breakloop:
1536 	if (*q != '\0')
1537 		return 0;
1538 	return 1;
1539 }
1540 
1541 
1542 
1543 /*
1544  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1545  */
1546 
1547 void
1548 rmescapes(char *str)
1549 {
1550 	char *p, *q;
1551 
1552 	p = str;
1553 	while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
1554 		if (*p++ == '\0')
1555 			return;
1556 	}
1557 	q = p;
1558 	while (*p) {
1559 		if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
1560 			p++;
1561 			continue;
1562 		}
1563 		if (*p == CTLESC)
1564 			p++;
1565 		*q++ = *p++;
1566 	}
1567 	*q = '\0';
1568 }
1569 
1570 
1571 
1572 /*
1573  * See if a pattern matches in a case statement.
1574  */
1575 
1576 int
1577 casematch(union node *pattern, const char *val)
1578 {
1579 	struct stackmark smark;
1580 	int result;
1581 	char *p;
1582 
1583 	setstackmark(&smark);
1584 	argbackq = pattern->narg.backquote;
1585 	STARTSTACKSTR(expdest);
1586 	ifslastp = NULL;
1587 	argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1588 	STPUTC('\0', expdest);
1589 	p = grabstackstr(expdest);
1590 	result = patmatch(p, val, 0);
1591 	popstackmark(&smark);
1592 	return result;
1593 }
1594 
1595 /*
1596  * Our own itoa().
1597  */
1598 
1599 static char *
1600 cvtnum(int num, char *buf)
1601 {
1602 	char temp[32];
1603 	int neg = num < 0;
1604 	char *p = temp + 31;
1605 
1606 	temp[31] = '\0';
1607 
1608 	do {
1609 		*--p = num % 10 + '0';
1610 	} while ((num /= 10) != 0);
1611 
1612 	if (neg)
1613 		*--p = '-';
1614 
1615 	STPUTS(p, buf);
1616 	return buf;
1617 }
1618 
1619 /*
1620  * Check statically if expanding a string may have side effects.
1621  */
1622 int
1623 expandhassideeffects(const char *p)
1624 {
1625 	int c;
1626 	int arinest;
1627 
1628 	arinest = 0;
1629 	while ((c = *p++) != '\0') {
1630 		switch (c) {
1631 		case CTLESC:
1632 			p++;
1633 			break;
1634 		case CTLVAR:
1635 			c = *p++;
1636 			/* Expanding $! sets the job to remembered. */
1637 			if (*p == '!')
1638 				return 1;
1639 			if ((c & VSTYPE) == VSASSIGN)
1640 				return 1;
1641 			/*
1642 			 * If we are in arithmetic, the parameter may contain
1643 			 * '=' which may cause side effects. Exceptions are
1644 			 * the length of a parameter and $$, $# and $? which
1645 			 * are always numeric.
1646 			 */
1647 			if ((c & VSTYPE) == VSLENGTH) {
1648 				while (*p != '=')
1649 					p++;
1650 				p++;
1651 				break;
1652 			}
1653 			if ((*p == '$' || *p == '#' || *p == '?') &&
1654 			    p[1] == '=') {
1655 				p += 2;
1656 				break;
1657 			}
1658 			if (arinest > 0)
1659 				return 1;
1660 			break;
1661 		case CTLBACKQ:
1662 		case CTLBACKQ | CTLQUOTE:
1663 			if (arinest > 0)
1664 				return 1;
1665 			break;
1666 		case CTLARI:
1667 			arinest++;
1668 			break;
1669 		case CTLENDARI:
1670 			arinest--;
1671 			break;
1672 		case '=':
1673 			if (*p == '=') {
1674 				/* Allow '==' operator. */
1675 				p++;
1676 				continue;
1677 			}
1678 			if (arinest > 0)
1679 				return 1;
1680 			break;
1681 		case '!': case '<': case '>':
1682 			/* Allow '!=', '<=', '>=' operators. */
1683 			if (*p == '=')
1684 				p++;
1685 			break;
1686 		}
1687 	}
1688 	return 0;
1689 }
1690 
1691 /*
1692  * Do most of the work for wordexp(3).
1693  */
1694 
1695 int
1696 wordexpcmd(int argc, char **argv)
1697 {
1698 	size_t len;
1699 	int i;
1700 
1701 	out1fmt("%08x", argc - 1);
1702 	for (i = 1, len = 0; i < argc; i++)
1703 		len += strlen(argv[i]);
1704 	out1fmt("%08x", (int)len);
1705 	for (i = 1; i < argc; i++)
1706 		outbin(argv[i], strlen(argv[i]) + 1, out1);
1707         return (0);
1708 }
1709