1f8298548c04b32bb51f3990b01a68cbd3298f38
[dragonfly.git] / bin / sh / expand.c
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  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *      This product includes software developed by the University of
21  *      California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  * @(#)expand.c 8.5 (Berkeley) 5/15/95
39  * $FreeBSD: src/bin/sh/expand.c,v 1.87 2011/06/09 23:12:23 jilles Exp $
40  */
41
42 #include <sys/types.h>
43 #include <sys/time.h>
44 #include <sys/stat.h>
45 #include <dirent.h>
46 #include <errno.h>
47 #include <inttypes.h>
48 #include <limits.h>
49 #include <pwd.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <wchar.h>
55
56 /*
57  * Routines to expand arguments to commands.  We have to deal with
58  * backquotes, shell variables, and file metacharacters.
59  */
60
61 #include "shell.h"
62 #include "main.h"
63 #include "nodes.h"
64 #include "eval.h"
65 #include "expand.h"
66 #include "syntax.h"
67 #include "parser.h"
68 #include "jobs.h"
69 #include "options.h"
70 #include "var.h"
71 #include "input.h"
72 #include "output.h"
73 #include "memalloc.h"
74 #include "error.h"
75 #include "mystring.h"
76 #include "arith.h"
77 #include "show.h"
78
79 /*
80  * Structure specifying which parts of the string should be searched
81  * for IFS characters.
82  */
83
84 struct ifsregion {
85         struct ifsregion *next; /* next region in list */
86         int begoff;             /* offset of start of region */
87         int endoff;             /* offset of end of region */
88         int inquotes;           /* search for nul bytes only */
89 };
90
91
92 static char *expdest;                   /* output of current string */
93 static struct nodelist *argbackq;       /* list of back quote expressions */
94 static struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
95 static struct ifsregion *ifslastp;      /* last struct in list */
96 static struct arglist exparg;           /* holds expanded arg list */
97
98 static void argstr(char *, int);
99 static char *exptilde(char *, int);
100 static void expbackq(union node *, int, int);
101 static int subevalvar(char *, char *, int, int, int, int, int);
102 static char *evalvar(char *, int);
103 static int varisset(char *, int);
104 static void varvalue(char *, int, int, int);
105 static void recordregion(int, int, int);
106 static void removerecordregions(int);
107 static void ifsbreakup(char *, struct arglist *);
108 static void expandmeta(struct strlist *, int);
109 static void expmeta(char *, char *);
110 static void addfname(char *);
111 static struct strlist *expsort(struct strlist *);
112 static struct strlist *msort(struct strlist *, int);
113 static char *cvtnum(int, char *);
114 static int collate_range_cmp(wchar_t, wchar_t);
115
116 static int
117 collate_range_cmp(wchar_t c1, wchar_t c2)
118 {
119         static wchar_t s1[2], s2[2];
120
121         s1[0] = c1;
122         s2[0] = c2;
123         return (wcscoll(s1, s2));
124 }
125
126 /*
127  * Expand shell variables and backquotes inside a here document.
128  *      union node *arg         the document
129  *      int fd;                 where to write the expanded version
130  */
131
132 void
133 expandhere(union node *arg, int fd)
134 {
135         expandarg(arg, NULL, 0);
136         xwrite(fd, stackblock(), expdest - stackblock());
137 }
138
139 static char *
140 stputs_quotes(const char *data, const char *syntax, char *p)
141 {
142         while (*data) {
143                 CHECKSTRSPACE(2, p);
144                 if (syntax[(int)*data] == CCTL)
145                         USTPUTC(CTLESC, p);
146                 USTPUTC(*data++, p);
147         }
148         return (p);
149 }
150 #define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
151
152 /*
153  * Perform expansions on an argument, placing the resulting list of arguments
154  * in arglist.  Parameter expansion, command substitution and arithmetic
155  * expansion are always performed; additional expansions can be requested
156  * via flag (EXP_*).
157  * The result is left in the stack string.
158  * When arglist is NULL, perform here document expansion.
159  *
160  * Caution: this function uses global state and is not reentrant.
161  * However, a new invocation after an interrupted invocation is safe
162  * and will reset the global state for the new call.
163  */
164 void
165 expandarg(union node *arg, struct arglist *arglist, int flag)
166 {
167         struct strlist *sp;
168         char *p;
169
170         argbackq = arg->narg.backquote;
171         STARTSTACKSTR(expdest);
172         ifsfirst.next = NULL;
173         ifslastp = NULL;
174         argstr(arg->narg.text, flag);
175         if (arglist == NULL) {
176                 STACKSTRNUL(expdest);
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, 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(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 = __DECONST(char *, ".");
1255         } else if (enddir == expdir + 1 && *expdir == '/') {
1256                 p = __DECONST(char *, "/");
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 = (unsigned char)*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 = (unsigned char)*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 = (unsigned char)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 = (unsigned char)*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 }