a7930e03539ae8cd6253ac28d2d73e34269935d0
[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 1.83 2011/02/21 09:01:34 brucec 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
55 /*
56  * Routines to expand arguments to commands.  We have to deal with
57  * backquotes, shell variables, and file metacharacters.
58  */
59
60 #include "shell.h"
61 #include "main.h"
62 #include "nodes.h"
63 #include "eval.h"
64 #include "expand.h"
65 #include "syntax.h"
66 #include "parser.h"
67 #include "jobs.h"
68 #include "options.h"
69 #include "var.h"
70 #include "input.h"
71 #include "output.h"
72 #include "memalloc.h"
73 #include "error.h"
74 #include "mystring.h"
75 #include "arith.h"
76 #include "show.h"
77
78 /*
79  * Structure specifying which parts of the string should be searched
80  * for IFS characters.
81  */
82
83 struct ifsregion {
84         struct ifsregion *next; /* next region in list */
85         int begoff;             /* offset of start of region */
86         int endoff;             /* offset of end of region */
87         int inquotes;           /* search for nul bytes only */
88 };
89
90
91 static char *expdest;                   /* output of current string */
92 static struct nodelist *argbackq;       /* list of back quote expressions */
93 static struct ifsregion ifsfirst;       /* first struct in list of ifs regions */
94 static struct ifsregion *ifslastp;      /* last struct in list */
95 static struct arglist exparg;           /* holds expanded arg list */
96
97 static void argstr(char *, int);
98 static char *exptilde(char *, int);
99 static void expbackq(union node *, int, int);
100 static int subevalvar(char *, char *, int, int, int, int, int);
101 static char *evalvar(char *, int);
102 static int varisset(char *, int);
103 static void varvalue(char *, int, int, int);
104 static void recordregion(int, int, int);
105 static void removerecordregions(int);
106 static void ifsbreakup(char *, struct arglist *);
107 static void expandmeta(struct strlist *, int);
108 static void expmeta(char *, char *);
109 static void addfname(char *);
110 static struct strlist *expsort(struct strlist *);
111 static struct strlist *msort(struct strlist *, int);
112 static char *cvtnum(int, char *);
113 static int collate_range_cmp(int, int);
114
115 static int
116 collate_range_cmp(int c1, int c2)
117 {
118         static char s1[2], s2[2];
119
120         s1[0] = c1;
121         s2[0] = c2;
122         return (strcoll(s1, s2));
123 }
124
125 /*
126  * Expand shell variables and backquotes inside a here document.
127  *      union node *arg         the document
128  *      int fd;                 where to write the expanded version
129  */
130
131 void
132 expandhere(union node *arg, int fd)
133 {
134         expandarg(arg, NULL, 0);
135         xwrite(fd, stackblock(), expdest - stackblock());
136 }
137
138 static char *
139 stputs_quotes(const char *data, const char *syntax, char *p)
140 {
141         while (*data) {
142                 CHECKSTRSPACE(2, p);
143                 if (syntax[(int)*data] == CCTL)
144                         USTPUTC(CTLESC, p);
145                 USTPUTC(*data++, p);
146         }
147         return (p);
148 }
149 #define STPUTS_QUOTES(data, syntax, p) p = stputs_quotes((data), syntax, p)
150
151 /*
152  * Perform expansions on an argument, placing the resulting list of arguments
153  * in arglist.  Parameter expansion, command substitution and arithmetic
154  * expansion are always performed; additional expansions can be requested
155  * via flag (EXP_*).
156  * The result is left in the stack string.
157  * When arglist is NULL, perform here document expansion.
158  *
159  * Caution: this function uses global state and is not reentrant.
160  * However, a new invocation after an interrupted invocation is safe
161  * and will reset the global state for the new call.
162  */
163 void
164 expandarg(union node *arg, struct arglist *arglist, int flag)
165 {
166         struct strlist *sp;
167         char *p;
168
169         argbackq = arg->narg.backquote;
170         STARTSTACKSTR(expdest);
171         ifsfirst.next = NULL;
172         ifslastp = NULL;
173         argstr(arg->narg.text, flag);
174         if (arglist == NULL) {
175                 return;                 /* here document expanded */
176         }
177         STPUTC('\0', expdest);
178         p = grabstackstr(expdest);
179         exparg.lastp = &exparg.list;
180         /*
181          * TODO - EXP_REDIR
182          */
183         if (flag & EXP_FULL) {
184                 ifsbreakup(p, &exparg);
185                 *exparg.lastp = NULL;
186                 exparg.lastp = &exparg.list;
187                 expandmeta(exparg.list, flag);
188         } else {
189                 if (flag & EXP_REDIR) /*XXX - for now, just remove escapes */
190                         rmescapes(p);
191                 sp = (struct strlist *)stalloc(sizeof (struct strlist));
192                 sp->text = p;
193                 *exparg.lastp = sp;
194                 exparg.lastp = &sp->next;
195         }
196         while (ifsfirst.next != NULL) {
197                 struct ifsregion *ifsp;
198                 INTOFF;
199                 ifsp = ifsfirst.next->next;
200                 ckfree(ifsfirst.next);
201                 ifsfirst.next = ifsp;
202                 INTON;
203         }
204         *exparg.lastp = NULL;
205         if (exparg.list) {
206                 *arglist->lastp = exparg.list;
207                 arglist->lastp = exparg.lastp;
208         }
209 }
210
211
212
213 /*
214  * Perform parameter expansion, command substitution and arithmetic
215  * expansion, and tilde expansion if requested via EXP_TILDE/EXP_VARTILDE.
216  * Processing ends at a CTLENDVAR character as well as '\0'.
217  * This is used to expand word in ${var+word} etc.
218  * If EXP_FULL, EXP_CASE or EXP_REDIR are set, keep and/or generate CTLESC
219  * characters to allow for further processing.
220  * If EXP_FULL is set, also preserve CTLQUOTEMARK characters.
221  */
222 static void
223 argstr(char *p, int flag)
224 {
225         char c;
226         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);  /* do CTLESC */
227         int firsteq = 1;
228         int split_lit;
229         int lit_quoted;
230
231         split_lit = flag & EXP_SPLIT_LIT;
232         lit_quoted = flag & EXP_LIT_QUOTED;
233         flag &= ~(EXP_SPLIT_LIT | EXP_LIT_QUOTED);
234         if (*p == '~' && (flag & (EXP_TILDE | EXP_VARTILDE)))
235                 p = exptilde(p, flag);
236         for (;;) {
237                 CHECKSTRSPACE(2, expdest);
238                 switch (c = *p++) {
239                 case '\0':
240                 case CTLENDVAR:
241                         goto breakloop;
242                 case CTLQUOTEMARK:
243                         lit_quoted = 1;
244                         /* "$@" syntax adherence hack */
245                         if (p[0] == CTLVAR && p[2] == '@' && p[3] == '=')
246                                 break;
247                         if ((flag & EXP_FULL) != 0)
248                                 USTPUTC(c, expdest);
249                         break;
250                 case CTLQUOTEEND:
251                         lit_quoted = 0;
252                         break;
253                 case CTLESC:
254                         if (quotes)
255                                 USTPUTC(c, expdest);
256                         c = *p++;
257                         USTPUTC(c, expdest);
258                         if (split_lit && !lit_quoted)
259                                 recordregion(expdest - stackblock() -
260                                     (quotes ? 2 : 1),
261                                     expdest - stackblock(), 0);
262                         break;
263                 case CTLVAR:
264                         p = evalvar(p, flag);
265                         break;
266                 case CTLBACKQ:
267                 case CTLBACKQ|CTLQUOTE:
268                         expbackq(argbackq->n, c & CTLQUOTE, flag);
269                         argbackq = argbackq->next;
270                         break;
271                 case CTLENDARI:
272                         expari(flag);
273                         break;
274                 case ':':
275                 case '=':
276                         /*
277                          * sort of a hack - expand tildes in variable
278                          * assignments (after the first '=' and after ':'s).
279                          */
280                         USTPUTC(c, expdest);
281                         if (split_lit && !lit_quoted)
282                                 recordregion(expdest - stackblock() - 1,
283                                     expdest - stackblock(), 0);
284                         if (flag & EXP_VARTILDE && *p == '~' &&
285                             (c != '=' || firsteq)) {
286                                 if (c == '=')
287                                         firsteq = 0;
288                                 p = exptilde(p, flag);
289                         }
290                         break;
291                 default:
292                         USTPUTC(c, expdest);
293                         if (split_lit && !lit_quoted)
294                                 recordregion(expdest - stackblock() - 1,
295                                     expdest - stackblock(), 0);
296                 }
297         }
298 breakloop:;
299 }
300
301 /*
302  * Perform tilde expansion, placing the result in the stack string and
303  * returning the next position in the input string to process.
304  */
305 static char *
306 exptilde(char *p, int flag)
307 {
308         char c, *startp = p;
309         struct passwd *pw;
310         char *home;
311         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
312
313         while ((c = *p) != '\0') {
314                 switch(c) {
315                 case CTLESC: /* This means CTL* are always considered quoted. */
316                 case CTLVAR:
317                 case CTLBACKQ:
318                 case CTLBACKQ | CTLQUOTE:
319                 case CTLARI:
320                 case CTLENDARI:
321                 case CTLQUOTEMARK:
322                         return (startp);
323                 case ':':
324                         if (flag & EXP_VARTILDE)
325                                 goto done;
326                         break;
327                 case '/':
328                 case CTLENDVAR:
329                         goto done;
330                 }
331                 p++;
332         }
333 done:
334         *p = '\0';
335         if (*(startp+1) == '\0') {
336                 if ((home = lookupvar("HOME")) == NULL)
337                         goto lose;
338         } else {
339                 if ((pw = getpwnam(startp+1)) == NULL)
340                         goto lose;
341                 home = pw->pw_dir;
342         }
343         if (*home == '\0')
344                 goto lose;
345         *p = c;
346         if (quotes)
347                 STPUTS_QUOTES(home, SQSYNTAX, expdest);
348         else
349                 STPUTS(home, expdest);
350         return (p);
351 lose:
352         *p = c;
353         return (startp);
354 }
355
356
357 static void
358 removerecordregions(int endoff)
359 {
360         if (ifslastp == NULL)
361                 return;
362
363         if (ifsfirst.endoff > endoff) {
364                 while (ifsfirst.next != NULL) {
365                         struct ifsregion *ifsp;
366                         INTOFF;
367                         ifsp = ifsfirst.next->next;
368                         ckfree(ifsfirst.next);
369                         ifsfirst.next = ifsp;
370                         INTON;
371                 }
372                 if (ifsfirst.begoff > endoff)
373                         ifslastp = NULL;
374                 else {
375                         ifslastp = &ifsfirst;
376                         ifsfirst.endoff = endoff;
377                 }
378                 return;
379         }
380
381         ifslastp = &ifsfirst;
382         while (ifslastp->next && ifslastp->next->begoff < endoff)
383                 ifslastp=ifslastp->next;
384         while (ifslastp->next != NULL) {
385                 struct ifsregion *ifsp;
386                 INTOFF;
387                 ifsp = ifslastp->next->next;
388                 ckfree(ifslastp->next);
389                 ifslastp->next = ifsp;
390                 INTON;
391         }
392         if (ifslastp->endoff > endoff)
393                 ifslastp->endoff = endoff;
394 }
395
396 /*
397  * Expand arithmetic expression.  Backup to start of expression,
398  * evaluate, place result in (backed up) result, adjust string position.
399  */
400 void
401 expari(int flag)
402 {
403         char *p, *q, *start;
404         arith_t result;
405         int begoff;
406         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
407         int quoted;
408
409         /*
410          * This routine is slightly over-complicated for
411          * efficiency.  First we make sure there is
412          * enough space for the result, which may be bigger
413          * than the expression.  Next we
414          * scan backwards looking for the start of arithmetic.  If the
415          * next previous character is a CTLESC character, then we
416          * have to rescan starting from the beginning since CTLESC
417          * characters have to be processed left to right.
418          */
419         CHECKSTRSPACE(DIGITS(result) - 2, expdest);
420         USTPUTC('\0', expdest);
421         start = stackblock();
422         p = expdest - 2;
423         while (p >= start && *p != CTLARI)
424                 --p;
425         if (p < start || *p != CTLARI)
426                 error("missing CTLARI (shouldn't happen)");
427         if (p > start && *(p - 1) == CTLESC)
428                 for (p = start; *p != CTLARI; p++)
429                         if (*p == CTLESC)
430                                 p++;
431
432         if (p[1] == '"')
433                 quoted=1;
434         else
435                 quoted=0;
436         begoff = p - start;
437         removerecordregions(begoff);
438         if (quotes)
439                 rmescapes(p+2);
440         q = grabstackstr(expdest);
441         result = arith(p+2);
442         ungrabstackstr(q, expdest);
443         fmtstr(p, DIGITS(result), ARITH_FORMAT_STR, result);
444         while (*p++)
445                 ;
446         if (quoted == 0)
447                 recordregion(begoff, p - 1 - start, 0);
448         result = expdest - p + 1;
449         STADJUST(-result, expdest);
450 }
451
452
453 /*
454  * Perform command substitution.
455  */
456 static void
457 expbackq(union node *cmd, int quoted, int flag)
458 {
459         struct backcmd in;
460         int i;
461         char buf[128];
462         char *p;
463         char *dest = expdest;
464         struct ifsregion saveifs, *savelastp;
465         struct nodelist *saveargbackq;
466         char lastc;
467         int startloc = dest - stackblock();
468         char const *syntax = quoted? DQSYNTAX : BASESYNTAX;
469         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
470         int nnl;
471
472         INTOFF;
473         saveifs = ifsfirst;
474         savelastp = ifslastp;
475         saveargbackq = argbackq;
476         p = grabstackstr(dest);
477         evalbackcmd(cmd, &in);
478         ungrabstackstr(p, dest);
479         ifsfirst = saveifs;
480         ifslastp = savelastp;
481         argbackq = saveargbackq;
482
483         p = in.buf;
484         lastc = '\0';
485         nnl = 0;
486         /* Don't copy trailing newlines */
487         for (;;) {
488                 if (--in.nleft < 0) {
489                         if (in.fd < 0)
490                                 break;
491                         while ((i = read(in.fd, buf, sizeof buf)) < 0 && errno == EINTR);
492                         TRACE(("expbackq: read returns %d\n", i));
493                         if (i <= 0)
494                                 break;
495                         p = buf;
496                         in.nleft = i - 1;
497                 }
498                 lastc = *p++;
499                 if (lastc != '\0') {
500                         if (lastc == '\n') {
501                                 nnl++;
502                         } else {
503                                 CHECKSTRSPACE(nnl + 2, dest);
504                                 while (nnl > 0) {
505                                         nnl--;
506                                         USTPUTC('\n', dest);
507                                 }
508                                 if (quotes && syntax[(int)lastc] == CCTL)
509                                         USTPUTC(CTLESC, dest);
510                                 USTPUTC(lastc, dest);
511                         }
512                 }
513         }
514
515         if (in.fd >= 0)
516                 close(in.fd);
517         if (in.buf)
518                 ckfree(in.buf);
519         if (in.jp)
520                 exitstatus = waitforjob(in.jp, NULL);
521         if (quoted == 0)
522                 recordregion(startloc, dest - stackblock(), 0);
523         TRACE(("expbackq: size=%td: \"%.*s\"\n",
524                 ((dest - stackblock()) - startloc),
525                 (int)((dest - stackblock()) - startloc),
526                 stackblock() + startloc));
527         expdest = dest;
528         INTON;
529 }
530
531
532
533 static int
534 subevalvar(char *p, char *str, int strloc, int subtype, int startloc,
535   int varflags, int quotes)
536 {
537         char *startp;
538         char *loc = NULL;
539         char *q;
540         int c = 0;
541         struct nodelist *saveargbackq = argbackq;
542         int amount;
543
544         argstr(p, (subtype == VSTRIMLEFT || subtype == VSTRIMLEFTMAX ||
545             subtype == VSTRIMRIGHT || subtype == VSTRIMRIGHTMAX ?
546             EXP_CASE : 0) | EXP_TILDE);
547         STACKSTRNUL(expdest);
548         argbackq = saveargbackq;
549         startp = stackblock() + startloc;
550         if (str == NULL)
551             str = stackblock() + strloc;
552
553         switch (subtype) {
554         case VSASSIGN:
555                 setvar(str, startp, 0);
556                 amount = startp - expdest;
557                 STADJUST(amount, expdest);
558                 varflags &= ~VSNUL;
559                 return 1;
560
561         case VSQUESTION:
562                 if (*p != CTLENDVAR) {
563                         outfmt(out2, "%s\n", startp);
564                         error(NULL);
565                 }
566                 error("%.*s: parameter %snot set", (int)(p - str - 1),
567                       str, (varflags & VSNUL) ? "null or "
568                                               : nullstr);
569                 return 0;
570
571         case VSTRIMLEFT:
572                 for (loc = startp; loc < str; loc++) {
573                         c = *loc;
574                         *loc = '\0';
575                         if (patmatch(str, startp, quotes)) {
576                                 *loc = c;
577                                 goto recordleft;
578                         }
579                         *loc = c;
580                         if (quotes && *loc == CTLESC)
581                                 loc++;
582                 }
583                 return 0;
584
585         case VSTRIMLEFTMAX:
586                 for (loc = str - 1; loc >= startp;) {
587                         c = *loc;
588                         *loc = '\0';
589                         if (patmatch(str, startp, quotes)) {
590                                 *loc = c;
591                                 goto recordleft;
592                         }
593                         *loc = c;
594                         loc--;
595                         if (quotes && loc > startp && *(loc - 1) == CTLESC) {
596                                 for (q = startp; q < loc; q++)
597                                         if (*q == CTLESC)
598                                                 q++;
599                                 if (q > loc)
600                                         loc--;
601                         }
602                 }
603                 return 0;
604
605         case VSTRIMRIGHT:
606                 for (loc = str - 1; loc >= startp;) {
607                         if (patmatch(str, loc, quotes)) {
608                                 amount = loc - expdest;
609                                 STADJUST(amount, expdest);
610                                 return 1;
611                         }
612                         loc--;
613                         if (quotes && loc > startp && *(loc - 1) == CTLESC) {
614                                 for (q = startp; q < loc; q++)
615                                         if (*q == CTLESC)
616                                                 q++;
617                                 if (q > loc)
618                                         loc--;
619                         }
620                 }
621                 return 0;
622
623         case VSTRIMRIGHTMAX:
624                 for (loc = startp; loc < str - 1; loc++) {
625                         if (patmatch(str, loc, quotes)) {
626                                 amount = loc - expdest;
627                                 STADJUST(amount, expdest);
628                                 return 1;
629                         }
630                         if (quotes && *loc == CTLESC)
631                                 loc++;
632                 }
633                 return 0;
634
635
636         default:
637                 abort();
638         }
639
640 recordleft:
641         amount = ((str - 1) - (loc - startp)) - expdest;
642         STADJUST(amount, expdest);
643         while (loc != str - 1)
644                 *startp++ = *loc++;
645         return 1;
646 }
647
648
649 /*
650  * Expand a variable, and return a pointer to the next character in the
651  * input string.
652  */
653
654 static char *
655 evalvar(char *p, int flag)
656 {
657         int subtype;
658         int varflags;
659         char *var;
660         char *val;
661         int patloc;
662         int c;
663         int set;
664         int special;
665         int startloc;
666         int varlen;
667         int easy;
668         int quotes = flag & (EXP_FULL | EXP_CASE | EXP_REDIR);
669
670         varflags = (unsigned char)*p++;
671         subtype = varflags & VSTYPE;
672         var = p;
673         special = 0;
674         if (! is_name(*p))
675                 special = 1;
676         p = strchr(p, '=') + 1;
677 again: /* jump here after setting a variable with ${var=text} */
678         if (varflags & VSLINENO) {
679                 set = 1;
680                 special = 0;
681                 val = var;
682                 p[-1] = '\0';   /* temporarily overwrite '=' to have \0
683                                    terminated string */
684         } else if (special) {
685                 set = varisset(var, varflags & VSNUL);
686                 val = NULL;
687         } else {
688                 val = bltinlookup(var, 1);
689                 if (val == NULL || ((varflags & VSNUL) && val[0] == '\0')) {
690                         val = NULL;
691                         set = 0;
692                 } else
693                         set = 1;
694         }
695         varlen = 0;
696         startloc = expdest - stackblock();
697         if (!set && uflag && *var != '@' && *var != '*') {
698                 switch (subtype) {
699                 case VSNORMAL:
700                 case VSTRIMLEFT:
701                 case VSTRIMLEFTMAX:
702                 case VSTRIMRIGHT:
703                 case VSTRIMRIGHTMAX:
704                 case VSLENGTH:
705                         error("%.*s: parameter not set", (int)(p - var - 1),
706                             var);
707                 }
708         }
709         if (set && subtype != VSPLUS) {
710                 /* insert the value of the variable */
711                 if (special) {
712                         varvalue(var, varflags & VSQUOTE, subtype, flag);
713                         if (subtype == VSLENGTH) {
714                                 varlen = expdest - stackblock() - startloc;
715                                 STADJUST(-varlen, expdest);
716                         }
717                 } else {
718                         char const *syntax = (varflags & VSQUOTE) ? DQSYNTAX
719                                                                   : BASESYNTAX;
720
721                         if (subtype == VSLENGTH) {
722                                 for (;*val; val++)
723                                         varlen++;
724                         }
725                         else {
726                                 if (quotes)
727                                         STPUTS_QUOTES(val, syntax, expdest);
728                                 else
729                                         STPUTS(val, expdest);
730
731                         }
732                 }
733         }
734
735         if (subtype == VSPLUS)
736                 set = ! set;
737
738         easy = ((varflags & VSQUOTE) == 0 ||
739                 (*var == '@' && shellparam.nparam != 1));
740
741
742         switch (subtype) {
743         case VSLENGTH:
744                 expdest = cvtnum(varlen, expdest);
745                 goto record;
746
747         case VSNORMAL:
748                 if (!easy)
749                         break;
750 record:
751                 recordregion(startloc, expdest - stackblock(),
752                              varflags & VSQUOTE);
753                 break;
754
755         case VSPLUS:
756         case VSMINUS:
757                 if (!set) {
758                         argstr(p, flag | (flag & EXP_FULL ? EXP_SPLIT_LIT : 0) |
759                             (varflags & VSQUOTE ? EXP_LIT_QUOTED : 0));
760                         break;
761                 }
762                 if (easy)
763                         goto record;
764                 break;
765
766         case VSTRIMLEFT:
767         case VSTRIMLEFTMAX:
768         case VSTRIMRIGHT:
769         case VSTRIMRIGHTMAX:
770                 if (!set)
771                         break;
772                 /*
773                  * Terminate the string and start recording the pattern
774                  * right after it
775                  */
776                 STPUTC('\0', expdest);
777                 patloc = expdest - stackblock();
778                 if (subevalvar(p, NULL, patloc, subtype,
779                     startloc, varflags, quotes) == 0) {
780                         int amount = (expdest - stackblock() - patloc) + 1;
781                         STADJUST(-amount, expdest);
782                 }
783                 /* Remove any recorded regions beyond start of variable */
784                 removerecordregions(startloc);
785                 goto record;
786
787         case VSASSIGN:
788         case VSQUESTION:
789                 if (!set) {
790                         if (subevalvar(p, var, 0, subtype, startloc, varflags,
791                             quotes)) {
792                                 varflags &= ~VSNUL;
793                                 /*
794                                  * Remove any recorded regions beyond
795                                  * start of variable
796                                  */
797                                 removerecordregions(startloc);
798                                 goto again;
799                         }
800                         break;
801                 }
802                 if (easy)
803                         goto record;
804                 break;
805
806         case VSERROR:
807                 c = p - var - 1;
808                 error("${%.*s%s}: Bad substitution", c, var,
809                     (c > 0 && *p != CTLENDVAR) ? "..." : "");
810
811         default:
812                 abort();
813         }
814         p[-1] = '=';    /* recover overwritten '=' */
815
816         if (subtype != VSNORMAL) {      /* skip to end of alternative */
817                 int nesting = 1;
818                 for (;;) {
819                         if ((c = *p++) == CTLESC)
820                                 p++;
821                         else if (c == CTLBACKQ || c == (CTLBACKQ|CTLQUOTE)) {
822                                 if (set)
823                                         argbackq = argbackq->next;
824                         } else if (c == CTLVAR) {
825                                 if ((*p++ & VSTYPE) != VSNORMAL)
826                                         nesting++;
827                         } else if (c == CTLENDVAR) {
828                                 if (--nesting == 0)
829                                         break;
830                         }
831                 }
832         }
833         return p;
834 }
835
836
837
838 /*
839  * Test whether a specialized variable is set.
840  */
841
842 static int
843 varisset(char *name, int nulok)
844 {
845
846         if (*name == '!')
847                 return backgndpidset();
848         else if (*name == '@' || *name == '*') {
849                 if (*shellparam.p == NULL)
850                         return 0;
851
852                 if (nulok) {
853                         char **av;
854
855                         for (av = shellparam.p; *av; av++)
856                                 if (**av != '\0')
857                                         return 1;
858                         return 0;
859                 }
860         } else if (is_digit(*name)) {
861                 char *ap;
862                 int num = atoi(name);
863
864                 if (num > shellparam.nparam)
865                         return 0;
866
867                 if (num == 0)
868                         ap = arg0;
869                 else
870                         ap = shellparam.p[num - 1];
871
872                 if (nulok && (ap == NULL || *ap == '\0'))
873                         return 0;
874         }
875         return 1;
876 }
877
878 static void
879 strtodest(const char *p, int flag, int subtype, int quoted)
880 {
881         if (flag & (EXP_FULL | EXP_CASE) && subtype != VSLENGTH)
882                 STPUTS_QUOTES(p, quoted ? DQSYNTAX : BASESYNTAX, expdest);
883         else
884                 STPUTS(p, expdest);
885 }
886
887 /*
888  * Add the value of a specialized variable to the stack string.
889  */
890
891 static void
892 varvalue(char *name, int quoted, int subtype, int flag)
893 {
894         int num;
895         char *p;
896         int i;
897         char sep;
898         char **ap;
899
900         switch (*name) {
901         case '$':
902                 num = rootpid;
903                 goto numvar;
904         case '?':
905                 num = oexitstatus;
906                 goto numvar;
907         case '#':
908                 num = shellparam.nparam;
909                 goto numvar;
910         case '!':
911                 num = backgndpidval();
912 numvar:
913                 expdest = cvtnum(num, expdest);
914                 break;
915         case '-':
916                 for (i = 0 ; i < NOPTS ; i++) {
917                         if (optlist[i].val)
918                                 STPUTC(optlist[i].letter, expdest);
919                 }
920                 break;
921         case '@':
922                 if (flag & EXP_FULL && quoted) {
923                         for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
924                                 strtodest(p, flag, subtype, quoted);
925                                 if (*ap)
926                                         STPUTC('\0', expdest);
927                         }
928                         break;
929                 }
930                 /* FALLTHROUGH */
931         case '*':
932                 if (ifsset())
933                         sep = ifsval()[0];
934                 else
935                         sep = ' ';
936                 for (ap = shellparam.p ; (p = *ap++) != NULL ; ) {
937                         strtodest(p, flag, subtype, quoted);
938                         if (*ap && sep)
939                                 STPUTC(sep, expdest);
940                 }
941                 break;
942         case '0':
943                 p = arg0;
944                 strtodest(p, flag, subtype, quoted);
945                 break;
946         default:
947                 if (is_digit(*name)) {
948                         num = atoi(name);
949                         if (num > 0 && num <= shellparam.nparam) {
950                                 p = shellparam.p[num - 1];
951                                 strtodest(p, flag, subtype, quoted);
952                         }
953                 }
954                 break;
955         }
956 }
957
958
959
960 /*
961  * Record the fact that we have to scan this region of the
962  * string for IFS characters.
963  */
964
965 static void
966 recordregion(int start, int end, int inquotes)
967 {
968         struct ifsregion *ifsp;
969
970         if (ifslastp == NULL) {
971                 ifsp = &ifsfirst;
972         } else {
973                 if (ifslastp->endoff == start
974                     && ifslastp->inquotes == inquotes) {
975                         /* extend previous area */
976                         ifslastp->endoff = end;
977                         return;
978                 }
979                 ifsp = (struct ifsregion *)ckmalloc(sizeof (struct ifsregion));
980                 ifslastp->next = ifsp;
981         }
982         ifslastp = ifsp;
983         ifslastp->next = NULL;
984         ifslastp->begoff = start;
985         ifslastp->endoff = end;
986         ifslastp->inquotes = inquotes;
987 }
988
989
990
991 /*
992  * Break the argument string into pieces based upon IFS and add the
993  * strings to the argument list.  The regions of the string to be
994  * searched for IFS characters have been stored by recordregion.
995  * CTLESC characters are preserved but have little effect in this pass
996  * other than escaping CTL* characters.  In particular, they do not escape
997  * IFS characters: that should be done with the ifsregion mechanism.
998  * CTLQUOTEMARK characters are used to preserve empty quoted strings.
999  * This pass treats them as a regular character, making the string non-empty.
1000  * Later, they are removed along with the other CTL* characters.
1001  */
1002 static void
1003 ifsbreakup(char *string, struct arglist *arglist)
1004 {
1005         struct ifsregion *ifsp;
1006         struct strlist *sp;
1007         char *start;
1008         char *p;
1009         char *q;
1010         const char *ifs;
1011         const char *ifsspc;
1012         int had_param_ch = 0;
1013
1014         start = string;
1015
1016         if (ifslastp == NULL) {
1017                 /* Return entire argument, IFS doesn't apply to any of it */
1018                 sp = (struct strlist *)stalloc(sizeof *sp);
1019                 sp->text = start;
1020                 *arglist->lastp = sp;
1021                 arglist->lastp = &sp->next;
1022                 return;
1023         }
1024
1025         ifs = ifsset() ? ifsval() : " \t\n";
1026
1027         for (ifsp = &ifsfirst; ifsp != NULL; ifsp = ifsp->next) {
1028                 p = string + ifsp->begoff;
1029                 while (p < string + ifsp->endoff) {
1030                         q = p;
1031                         if (*p == CTLESC)
1032                                 p++;
1033                         if (ifsp->inquotes) {
1034                                 /* Only NULs (should be from "$@") end args */
1035                                 had_param_ch = 1;
1036                                 if (*p != 0) {
1037                                         p++;
1038                                         continue;
1039                                 }
1040                                 ifsspc = NULL;
1041                         } else {
1042                                 if (!strchr(ifs, *p)) {
1043                                         had_param_ch = 1;
1044                                         p++;
1045                                         continue;
1046                                 }
1047                                 ifsspc = strchr(" \t\n", *p);
1048
1049                                 /* Ignore IFS whitespace at start */
1050                                 if (q == start && ifsspc != NULL) {
1051                                         p++;
1052                                         start = p;
1053                                         continue;
1054                                 }
1055                                 had_param_ch = 0;
1056                         }
1057
1058                         /* Save this argument... */
1059                         *q = '\0';
1060                         sp = (struct strlist *)stalloc(sizeof *sp);
1061                         sp->text = start;
1062                         *arglist->lastp = sp;
1063                         arglist->lastp = &sp->next;
1064                         p++;
1065
1066                         if (ifsspc != NULL) {
1067                                 /* Ignore further trailing IFS whitespace */
1068                                 for (; p < string + ifsp->endoff; p++) {
1069                                         q = p;
1070                                         if (*p == CTLESC)
1071                                                 p++;
1072                                         if (strchr(ifs, *p) == NULL) {
1073                                                 p = q;
1074                                                 break;
1075                                         }
1076                                         if (strchr(" \t\n", *p) == NULL) {
1077                                                 p++;
1078                                                 break;
1079                                         }
1080                                 }
1081                         }
1082                         start = p;
1083                 }
1084         }
1085
1086         /*
1087          * Save anything left as an argument.
1088          * Traditionally we have treated 'IFS=':'; set -- x$IFS' as
1089          * generating 2 arguments, the second of which is empty.
1090          * Some recent clarification of the Posix spec say that it
1091          * should only generate one....
1092          */
1093         if (had_param_ch || *start != 0) {
1094                 sp = (struct strlist *)stalloc(sizeof *sp);
1095                 sp->text = start;
1096                 *arglist->lastp = sp;
1097                 arglist->lastp = &sp->next;
1098         }
1099 }
1100
1101
1102 static char expdir[PATH_MAX];
1103 #define expdir_end (expdir + sizeof(expdir))
1104
1105 /*
1106  * Perform pathname generation and remove control characters.
1107  * At this point, the only control characters should be CTLESC and CTLQUOTEMARK.
1108  * The results are stored in the list exparg.
1109  */
1110 static void
1111 expandmeta(struct strlist *str, int flag __unused)
1112 {
1113         char *p;
1114         struct strlist **savelastp;
1115         struct strlist *sp;
1116         char c;
1117         /* TODO - EXP_REDIR */
1118
1119         while (str) {
1120                 if (fflag)
1121                         goto nometa;
1122                 p = str->text;
1123                 for (;;) {                      /* fast check for meta chars */
1124                         if ((c = *p++) == '\0')
1125                                 goto nometa;
1126                         if (c == '*' || c == '?' || c == '[')
1127                                 break;
1128                 }
1129                 savelastp = exparg.lastp;
1130                 INTOFF;
1131                 expmeta(expdir, str->text);
1132                 INTON;
1133                 if (exparg.lastp == savelastp) {
1134                         /*
1135                          * no matches
1136                          */
1137 nometa:
1138                         *exparg.lastp = str;
1139                         rmescapes(str->text);
1140                         exparg.lastp = &str->next;
1141                 } else {
1142                         *exparg.lastp = NULL;
1143                         *savelastp = sp = expsort(*savelastp);
1144                         while (sp->next != NULL)
1145                                 sp = sp->next;
1146                         exparg.lastp = &sp->next;
1147                 }
1148                 str = str->next;
1149         }
1150 }
1151
1152
1153 /*
1154  * Do metacharacter (i.e. *, ?, [...]) expansion.
1155  */
1156
1157 static void
1158 expmeta(char *enddir, char *name)
1159 {
1160         char *p;
1161         char *q;
1162         char *start;
1163         char *endname;
1164         int metaflag;
1165         struct stat statb;
1166         DIR *dirp;
1167         struct dirent *dp;
1168         int atend;
1169         int matchdot;
1170         int esc;
1171
1172         metaflag = 0;
1173         start = name;
1174         for (p = name; esc = 0, *p; p += esc + 1) {
1175                 if (*p == '*' || *p == '?')
1176                         metaflag = 1;
1177                 else if (*p == '[') {
1178                         q = p + 1;
1179                         if (*q == '!' || *q == '^')
1180                                 q++;
1181                         for (;;) {
1182                                 while (*q == CTLQUOTEMARK)
1183                                         q++;
1184                                 if (*q == CTLESC)
1185                                         q++;
1186                                 if (*q == '/' || *q == '\0')
1187                                         break;
1188                                 if (*++q == ']') {
1189                                         metaflag = 1;
1190                                         break;
1191                                 }
1192                         }
1193                 } else if (*p == '\0')
1194                         break;
1195                 else if (*p == CTLQUOTEMARK)
1196                         continue;
1197                 else {
1198                         if (*p == CTLESC)
1199                                 esc++;
1200                         if (p[esc] == '/') {
1201                                 if (metaflag)
1202                                         break;
1203                                 start = p + esc + 1;
1204                         }
1205                 }
1206         }
1207         if (metaflag == 0) {    /* we've reached the end of the file name */
1208                 if (enddir != expdir)
1209                         metaflag++;
1210                 for (p = name ; ; p++) {
1211                         if (*p == CTLQUOTEMARK)
1212                                 continue;
1213                         if (*p == CTLESC)
1214                                 p++;
1215                         *enddir++ = *p;
1216                         if (*p == '\0')
1217                                 break;
1218                         if (enddir == expdir_end)
1219                                 return;
1220                 }
1221                 if (metaflag == 0 || lstat(expdir, &statb) >= 0)
1222                         addfname(expdir);
1223                 return;
1224         }
1225         endname = p;
1226         if (start != name) {
1227                 p = name;
1228                 while (p < start) {
1229                         while (*p == CTLQUOTEMARK)
1230                                 p++;
1231                         if (*p == CTLESC)
1232                                 p++;
1233                         *enddir++ = *p++;
1234                         if (enddir == expdir_end)
1235                                 return;
1236                 }
1237         }
1238         if (enddir == expdir) {
1239                 p = __DECONST(char *, ".");
1240         } else if (enddir == expdir + 1 && *expdir == '/') {
1241                 p = __DECONST(char *, "/");
1242         } else {
1243                 p = expdir;
1244                 enddir[-1] = '\0';
1245         }
1246         if ((dirp = opendir(p)) == NULL)
1247                 return;
1248         if (enddir != expdir)
1249                 enddir[-1] = '/';
1250         if (*endname == 0) {
1251                 atend = 1;
1252         } else {
1253                 atend = 0;
1254                 *endname = '\0';
1255                 endname += esc + 1;
1256         }
1257         matchdot = 0;
1258         p = start;
1259         while (*p == CTLQUOTEMARK)
1260                 p++;
1261         if (*p == CTLESC)
1262                 p++;
1263         if (*p == '.')
1264                 matchdot++;
1265         while (! int_pending() && (dp = readdir(dirp)) != NULL) {
1266                 if (dp->d_name[0] == '.' && ! matchdot)
1267                         continue;
1268                 if (patmatch(start, dp->d_name, 0)) {
1269                         if (enddir + dp->d_namlen + 1 > expdir_end)
1270                                 continue;
1271                         memcpy(enddir, dp->d_name, dp->d_namlen + 1);
1272                         if (atend)
1273                                 addfname(expdir);
1274                         else {
1275                                 if (enddir + dp->d_namlen + 2 > expdir_end)
1276                                         continue;
1277                                 enddir[dp->d_namlen] = '/';
1278                                 enddir[dp->d_namlen + 1] = '\0';
1279                                 expmeta(enddir + dp->d_namlen + 1, endname);
1280                         }
1281                 }
1282         }
1283         closedir(dirp);
1284         if (! atend)
1285                 endname[-esc - 1] = esc ? CTLESC : '/';
1286 }
1287
1288
1289 /*
1290  * Add a file name to the list.
1291  */
1292
1293 static void
1294 addfname(char *name)
1295 {
1296         char *p;
1297         struct strlist *sp;
1298
1299         p = stalloc(strlen(name) + 1);
1300         scopy(name, p);
1301         sp = (struct strlist *)stalloc(sizeof *sp);
1302         sp->text = p;
1303         *exparg.lastp = sp;
1304         exparg.lastp = &sp->next;
1305 }
1306
1307
1308 /*
1309  * Sort the results of file name expansion.  It calculates the number of
1310  * strings to sort and then calls msort (short for merge sort) to do the
1311  * work.
1312  */
1313
1314 static struct strlist *
1315 expsort(struct strlist *str)
1316 {
1317         int len;
1318         struct strlist *sp;
1319
1320         len = 0;
1321         for (sp = str ; sp ; sp = sp->next)
1322                 len++;
1323         return msort(str, len);
1324 }
1325
1326
1327 static struct strlist *
1328 msort(struct strlist *list, int len)
1329 {
1330         struct strlist *p, *q = NULL;
1331         struct strlist **lpp;
1332         int half;
1333         int n;
1334
1335         if (len <= 1)
1336                 return list;
1337         half = len >> 1;
1338         p = list;
1339         for (n = half ; --n >= 0 ; ) {
1340                 q = p;
1341                 p = p->next;
1342         }
1343         q->next = NULL;                 /* terminate first half of list */
1344         q = msort(list, half);          /* sort first half of list */
1345         p = msort(p, len - half);               /* sort second half */
1346         lpp = &list;
1347         for (;;) {
1348                 if (strcmp(p->text, q->text) < 0) {
1349                         *lpp = p;
1350                         lpp = &p->next;
1351                         if ((p = *lpp) == NULL) {
1352                                 *lpp = q;
1353                                 break;
1354                         }
1355                 } else {
1356                         *lpp = q;
1357                         lpp = &q->next;
1358                         if ((q = *lpp) == NULL) {
1359                                 *lpp = p;
1360                                 break;
1361                         }
1362                 }
1363         }
1364         return list;
1365 }
1366
1367
1368
1369 /*
1370  * Returns true if the pattern matches the string.
1371  */
1372
1373 int
1374 patmatch(const char *pattern, const char *string, int squoted)
1375 {
1376         const char *p, *q;
1377         char c;
1378
1379         p = pattern;
1380         q = string;
1381         for (;;) {
1382                 switch (c = *p++) {
1383                 case '\0':
1384                         goto breakloop;
1385                 case CTLESC:
1386                         if (squoted && *q == CTLESC)
1387                                 q++;
1388                         if (*q++ != *p++)
1389                                 return 0;
1390                         break;
1391                 case CTLQUOTEMARK:
1392                         continue;
1393                 case '?':
1394                         if (squoted && *q == CTLESC)
1395                                 q++;
1396                         if (*q++ == '\0')
1397                                 return 0;
1398                         break;
1399                 case '*':
1400                         c = *p;
1401                         while (c == CTLQUOTEMARK || c == '*')
1402                                 c = *++p;
1403                         if (c != CTLESC &&  c != CTLQUOTEMARK &&
1404                             c != '?' && c != '*' && c != '[') {
1405                                 while (*q != c) {
1406                                         if (squoted && *q == CTLESC &&
1407                                             q[1] == c)
1408                                                 break;
1409                                         if (*q == '\0')
1410                                                 return 0;
1411                                         if (squoted && *q == CTLESC)
1412                                                 q++;
1413                                         q++;
1414                                 }
1415                         }
1416                         do {
1417                                 if (patmatch(p, q, squoted))
1418                                         return 1;
1419                                 if (squoted && *q == CTLESC)
1420                                         q++;
1421                         } while (*q++ != '\0');
1422                         return 0;
1423                 case '[': {
1424                         const char *endp;
1425                         int invert, found;
1426                         char chr;
1427
1428                         endp = p;
1429                         if (*endp == '!' || *endp == '^')
1430                                 endp++;
1431                         for (;;) {
1432                                 while (*endp == CTLQUOTEMARK)
1433                                         endp++;
1434                                 if (*endp == '\0')
1435                                         goto dft;               /* no matching ] */
1436                                 if (*endp == CTLESC)
1437                                         endp++;
1438                                 if (*++endp == ']')
1439                                         break;
1440                         }
1441                         invert = 0;
1442                         if (*p == '!' || *p == '^') {
1443                                 invert++;
1444                                 p++;
1445                         }
1446                         found = 0;
1447                         chr = *q++;
1448                         if (squoted && chr == CTLESC)
1449                                 chr = *q++;
1450                         if (chr == '\0')
1451                                 return 0;
1452                         c = *p++;
1453                         do {
1454                                 if (c == CTLQUOTEMARK)
1455                                         continue;
1456                                 if (c == CTLESC)
1457                                         c = *p++;
1458                                 if (*p == '-' && p[1] != ']') {
1459                                         p++;
1460                                         while (*p == CTLQUOTEMARK)
1461                                                 p++;
1462                                         if (*p == CTLESC)
1463                                                 p++;
1464                                         if (   collate_range_cmp(chr, c) >= 0
1465                                             && collate_range_cmp(chr, *p) <= 0
1466                                            )
1467                                                 found = 1;
1468                                         p++;
1469                                 } else {
1470                                         if (chr == c)
1471                                                 found = 1;
1472                                 }
1473                         } while ((c = *p++) != ']');
1474                         if (found == invert)
1475                                 return 0;
1476                         break;
1477                 }
1478 dft:            default:
1479                         if (squoted && *q == CTLESC)
1480                                 q++;
1481                         if (*q++ != c)
1482                                 return 0;
1483                         break;
1484                 }
1485         }
1486 breakloop:
1487         if (*q != '\0')
1488                 return 0;
1489         return 1;
1490 }
1491
1492
1493
1494 /*
1495  * Remove any CTLESC and CTLQUOTEMARK characters from a string.
1496  */
1497
1498 void
1499 rmescapes(char *str)
1500 {
1501         char *p, *q;
1502
1503         p = str;
1504         while (*p != CTLESC && *p != CTLQUOTEMARK && *p != CTLQUOTEEND) {
1505                 if (*p++ == '\0')
1506                         return;
1507         }
1508         q = p;
1509         while (*p) {
1510                 if (*p == CTLQUOTEMARK || *p == CTLQUOTEEND) {
1511                         p++;
1512                         continue;
1513                 }
1514                 if (*p == CTLESC)
1515                         p++;
1516                 *q++ = *p++;
1517         }
1518         *q = '\0';
1519 }
1520
1521
1522
1523 /*
1524  * See if a pattern matches in a case statement.
1525  */
1526
1527 int
1528 casematch(union node *pattern, const char *val)
1529 {
1530         struct stackmark smark;
1531         int result;
1532         char *p;
1533
1534         setstackmark(&smark);
1535         argbackq = pattern->narg.backquote;
1536         STARTSTACKSTR(expdest);
1537         ifslastp = NULL;
1538         argstr(pattern->narg.text, EXP_TILDE | EXP_CASE);
1539         STPUTC('\0', expdest);
1540         p = grabstackstr(expdest);
1541         result = patmatch(p, val, 0);
1542         popstackmark(&smark);
1543         return result;
1544 }
1545
1546 /*
1547  * Our own itoa().
1548  */
1549
1550 static char *
1551 cvtnum(int num, char *buf)
1552 {
1553         char temp[32];
1554         int neg = num < 0;
1555         char *p = temp + 31;
1556
1557         temp[31] = '\0';
1558
1559         do {
1560                 *--p = num % 10 + '0';
1561         } while ((num /= 10) != 0);
1562
1563         if (neg)
1564                 *--p = '-';
1565
1566         STPUTS(p, buf);
1567         return buf;
1568 }
1569
1570 /*
1571  * Check statically if expanding a string may have side effects.
1572  */
1573 int
1574 expandhassideeffects(const char *p)
1575 {
1576         int c;
1577         int arinest;
1578
1579         arinest = 0;
1580         while ((c = *p++) != '\0') {
1581                 switch (c) {
1582                 case CTLESC:
1583                         p++;
1584                         break;
1585                 case CTLVAR:
1586                         c = *p++;
1587                         /* Expanding $! sets the job to remembered. */
1588                         if (*p == '!')
1589                                 return 1;
1590                         if ((c & VSTYPE) == VSASSIGN)
1591                                 return 1;
1592                         /*
1593                          * If we are in arithmetic, the parameter may contain
1594                          * '=' which may cause side effects. Exceptions are
1595                          * the length of a parameter and $$, $# and $? which
1596                          * are always numeric.
1597                          */
1598                         if ((c & VSTYPE) == VSLENGTH) {
1599                                 while (*p != '=')
1600                                         p++;
1601                                 p++;
1602                                 break;
1603                         }
1604                         if ((*p == '$' || *p == '#' || *p == '?') &&
1605                             p[1] == '=') {
1606                                 p += 2;
1607                                 break;
1608                         }
1609                         if (arinest > 0)
1610                                 return 1;
1611                         break;
1612                 case CTLBACKQ:
1613                 case CTLBACKQ | CTLQUOTE:
1614                         if (arinest > 0)
1615                                 return 1;
1616                         break;
1617                 case CTLARI:
1618                         arinest++;
1619                         break;
1620                 case CTLENDARI:
1621                         arinest--;
1622                         break;
1623                 case '=':
1624                         if (*p == '=') {
1625                                 /* Allow '==' operator. */
1626                                 p++;
1627                                 continue;
1628                         }
1629                         if (arinest > 0)
1630                                 return 1;
1631                         break;
1632                 case '!': case '<': case '>':
1633                         /* Allow '!=', '<=', '>=' operators. */
1634                         if (*p == '=')
1635                                 p++;
1636                         break;
1637                 }
1638         }
1639         return 0;
1640 }
1641
1642 /*
1643  * Do most of the work for wordexp(3).
1644  */
1645
1646 int
1647 wordexpcmd(int argc, char **argv)
1648 {
1649         size_t len;
1650         int i;
1651
1652         out1fmt("%08x", argc - 1);
1653         for (i = 1, len = 0; i < argc; i++)
1654                 len += strlen(argv[i]);
1655         out1fmt("%08x", (int)len);
1656         for (i = 1; i < argc; i++)
1657                 outbin(argv[i], strlen(argv[i]) + 1, out1);
1658         return (0);
1659 }