xref: /freebsd/contrib/tcsh/sh.exp.c (revision 3f0164abf32b9b761e0a2cb4bdca3a8b84f156d4)
1 /* $Header: /p/tcsh/cvsroot/tcsh/sh.exp.c,v 3.58 2011/12/25 15:21:50 christos Exp $ */
2 /*
3  * sh.exp.c: Expression evaluations
4  */
5 /*-
6  * Copyright (c) 1980, 1991 The Regents of the University of California.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 #include "sh.h"
34 
35 RCSID("$tcsh: sh.exp.c,v 3.58 2011/12/25 15:21:50 christos Exp $")
36 
37 #include "tw.h"
38 
39 /*
40  * C shell
41  */
42 
43 #define TEXP_IGNORE 1	/* in ignore, it means to ignore value, just parse */
44 #define TEXP_NOGLOB 2	/* in ignore, it means not to globone */
45 
46 #define	ADDOP	1
47 #define	MULOP	2
48 #define	EQOP	4
49 #define	RELOP	8
50 #define	RESTOP	16
51 #define	ANYOP	31
52 
53 #define	EQEQ	1
54 #define	GTR	2
55 #define	LSS	4
56 #define	NOTEQ	6
57 #define EQMATCH 7
58 #define NOTEQMATCH 8
59 
60 static	int	   sh_access	(const Char *, int);
61 static	tcsh_number_t  exp1		(Char ***, int);
62 static	tcsh_number_t  exp2x	(Char ***, int);
63 static	tcsh_number_t  exp2a	(Char ***, int);
64 static	tcsh_number_t  exp2b	(Char ***, int);
65 static	tcsh_number_t  exp2c	(Char ***, int);
66 static	Char 	  *exp3		(Char ***, int);
67 static	Char 	  *exp3a	(Char ***, int);
68 static	Char 	  *exp4		(Char ***, int);
69 static	Char 	  *exp5		(Char ***, int);
70 static	Char 	  *exp6		(Char ***, int);
71 static	void	   evalav	(Char **);
72 static	int	   isa		(Char *, int);
73 static	tcsh_number_t  egetn	(const Char *);
74 
75 #ifdef EDEBUG
76 static	void	   etracc	(const char *, const Char *, Char ***);
77 static	void	   etraci	(const char *, tcsh_number_t, Char ***);
78 #else /* !EDEBUG */
79 #define etracc(A, B, C) ((void)0)
80 #define etraci(A, B, C) ((void)0)
81 #endif /* !EDEBUG */
82 
83 /*
84  * shell access function according to POSIX and non POSIX
85  * From Beto Appleton (beto@aixwiz.aix.ibm.com)
86  */
87 static int
88 sh_access(const Char *fname, int mode)
89 {
90 #if defined(POSIX) && !defined(USE_ACCESS)
91     struct stat     statb;
92 #endif /* POSIX */
93     char *name = short2str(fname);
94 
95     if (*name == '\0')
96 	return 1;
97 
98 #if !defined(POSIX) || defined(USE_ACCESS)
99     return access(name, mode);
100 #else /* POSIX */
101 
102     /*
103      * POSIX 1003.2-d11.2
104      *	-r file		True if file exists and is readable.
105      *	-w file		True if file exists and is writable.
106      *			True shall indicate only that the write flag is on.
107      *			The file shall not be writable on a read-only file
108      *			system even if this test indicates true.
109      *	-x file		True if file exists and is executable.
110      *			True shall indicate only that the execute flag is on.
111      *			If file is a directory, true indicates that the file
112      *			can be searched.
113      */
114     if (mode != W_OK && mode != X_OK)
115 	return access(name, mode);
116 
117     if (stat(name, &statb) == -1)
118 	return 1;
119 
120     if (access(name, mode) == 0) {
121 #ifdef S_ISDIR
122 	if (S_ISDIR(statb.st_mode) && mode == X_OK)
123 	    return 0;
124 #endif /* S_ISDIR */
125 
126 	/* root needs permission for someone */
127 	switch (mode) {
128 	case W_OK:
129 	    mode = S_IWUSR | S_IWGRP | S_IWOTH;
130 	    break;
131 	case X_OK:
132 	    mode = S_IXUSR | S_IXGRP | S_IXOTH;
133 	    break;
134 	default:
135 	    abort();
136 	    break;
137 	}
138 
139     }
140 
141     else if (euid == statb.st_uid)
142 	mode <<= 6;
143 
144     else if (egid == statb.st_gid)
145 	mode <<= 3;
146 
147 # ifdef NGROUPS_MAX
148     else {
149 	/* you can be in several groups */
150 	long	n;
151 	GETGROUPS_T *groups;
152 
153 	/*
154 	 * Try these things to find a positive maximum groups value:
155 	 *   1) sysconf(_SC_NGROUPS_MAX)
156 	 *   2) NGROUPS_MAX
157 	 *   3) getgroups(0, unused)
158 	 * Then allocate and scan the groups array if one of these worked.
159 	 */
160 #  if defined (HAVE_SYSCONF) && defined (_SC_NGROUPS_MAX)
161 	if ((n = sysconf(_SC_NGROUPS_MAX)) == -1)
162 #  endif /* _SC_NGROUPS_MAX */
163 	    n = NGROUPS_MAX;
164 	if (n <= 0)
165 	    n = getgroups(0, (GETGROUPS_T *) NULL);
166 
167 	if (n > 0) {
168 	    groups = xmalloc(n * sizeof(*groups));
169 	    n = getgroups((int) n, groups);
170 	    while (--n >= 0)
171 		if (groups[n] == statb.st_gid) {
172 		    mode <<= 3;
173 		    break;
174 		}
175 	}
176     }
177 # endif /* NGROUPS_MAX */
178 
179     if (statb.st_mode & mode)
180 	return 0;
181     else
182 	return 1;
183 #endif /* !POSIX */
184 }
185 
186 tcsh_number_t
187 expr(Char ***vp)
188 {
189     return (exp0(vp, 0));
190 }
191 
192 tcsh_number_t
193 exp0(Char ***vp, int ignore)
194 {
195     tcsh_number_t p1 = exp1(vp, ignore);
196 
197     etraci("exp0 p1", p1, vp);
198     while (**vp && eq(**vp, STRor2)) {
199 	int p2;
200 
201 	(*vp)++;
202 
203 	p2 = compat_expr ?
204 	    exp0(vp, (ignore & TEXP_IGNORE) || p1) :
205 	    exp1(vp, (ignore & TEXP_IGNORE) || p1);
206 	if (compat_expr || !(ignore & TEXP_IGNORE))
207 	    p1 = (p1 || p2);
208 	etraci("exp0 p1", p1, vp);
209 	if (compat_expr)
210 	    break;
211     }
212     return (p1);
213 }
214 
215 static tcsh_number_t
216 exp1(Char ***vp, int ignore)
217 {
218     tcsh_number_t p1 = exp2x(vp, ignore);
219 
220     etraci("exp1 p1", p1, vp);
221     while (**vp && eq(**vp, STRand2)) {
222 	tcsh_number_t p2;
223 
224 	(*vp)++;
225 	p2 = compat_expr ?
226 	    exp1(vp, (ignore & TEXP_IGNORE) || !p1) :
227 	    exp2x(vp, (ignore & TEXP_IGNORE) || !p1);
228 
229 	etraci("exp1 p2", p2, vp);
230 	if (compat_expr || !(ignore & TEXP_IGNORE))
231 	    p1 = (p1 && p2);
232 	etraci("exp1 p1", p1, vp);
233 	if (compat_expr)
234 	    break;
235     }
236     return (p1);
237 }
238 
239 static tcsh_number_t
240 exp2x(Char ***vp, int ignore)
241 {
242     tcsh_number_t p1 = exp2a(vp, ignore);
243 
244     etraci("exp2x p1", p1, vp);
245     while (**vp && eq(**vp, STRor)) {
246 	tcsh_number_t p2;
247 
248 	(*vp)++;
249 	p2 = compat_expr ?
250 	    exp2x(vp, ignore) :
251 	    exp2a(vp, ignore);
252 	etraci("exp2x p2", p2, vp);
253 	if (compat_expr || !(ignore & TEXP_IGNORE))
254 		p1 = (p1 | p2);
255 	etraci("exp2x p1", p1, vp);
256 	if (compat_expr)
257 	    break;
258     }
259     return (p1);
260 }
261 
262 static tcsh_number_t
263 exp2a(Char ***vp, int ignore)
264 {
265     tcsh_number_t p1 = exp2b(vp, ignore);
266 
267     etraci("exp2a p1", p1, vp);
268     while (**vp && eq(**vp, STRcaret)) {
269 	tcsh_number_t p2;
270 
271 	(*vp)++;
272 	p2 = compat_expr ?
273 	    exp2a(vp, ignore) :
274 	    exp2b(vp, ignore);
275 	etraci("exp2a p2", p2, vp);
276 	if (compat_expr || !(ignore & TEXP_IGNORE))
277 	    p1 = (p1 ^ p2);
278 	etraci("exp2a p1", p1, vp);
279 	if (compat_expr)
280 	    break;
281     }
282     return (p1);
283 }
284 
285 static tcsh_number_t
286 exp2b(Char ***vp, int ignore)
287 {
288     tcsh_number_t p1 = exp2c(vp, ignore);
289 
290     etraci("exp2b p1", p1, vp);
291     while (**vp && eq(**vp, STRand)) {
292 	tcsh_number_t p2;
293 
294 	(*vp)++;
295 	p2 = compat_expr ?
296 	    exp2b(vp, ignore) :
297 	    exp2c(vp, ignore);
298 	etraci("exp2b p2", p2, vp);
299 	if (compat_expr || !(ignore & TEXP_IGNORE))
300 	    p1 = (p1 & p2);
301 	etraci("exp2b p1", p1, vp);
302 	if (compat_expr)
303 	    break;
304     }
305     return (p1);
306 }
307 
308 static tcsh_number_t
309 exp2c(Char ***vp, int ignore)
310 {
311     Char *p1 = exp3(vp, ignore);
312     Char *p2;
313     tcsh_number_t i;
314 
315     cleanup_push(p1, xfree);
316     etracc("exp2c p1", p1, vp);
317     if ((i = isa(**vp, EQOP)) != 0) {
318 	(*vp)++;
319 	if (i == EQMATCH || i == NOTEQMATCH)
320 	    ignore |= TEXP_NOGLOB;
321 	p2 = exp3(vp, ignore);
322 	cleanup_push(p2, xfree);
323 	etracc("exp2c p2", p2, vp);
324 	if (!(ignore & TEXP_IGNORE))
325 	    switch (i) {
326 
327 	    case EQEQ:
328 		i = eq(p1, p2);
329 		break;
330 
331 	    case NOTEQ:
332 		i = !eq(p1, p2);
333 		break;
334 
335 	    case EQMATCH:
336 		i = Gmatch(p1, p2);
337 		break;
338 
339 	    case NOTEQMATCH:
340 		i = !Gmatch(p1, p2);
341 		break;
342 	    }
343 	cleanup_until(p1);
344 	return (i);
345     }
346     i = egetn(p1);
347     cleanup_until(p1);
348     return (i);
349 }
350 
351 static Char *
352 exp3(Char ***vp, int ignore)
353 {
354     Char *p1, *p2;
355     tcsh_number_t i;
356 
357     p1 = exp3a(vp, ignore);
358     etracc("exp3 p1", p1, vp);
359     while ((i = isa(**vp, RELOP)) != 0) {
360 	(*vp)++;
361 	if (**vp && eq(**vp, STRequal))
362 	    i |= 1, (*vp)++;
363 	cleanup_push(p1, xfree);
364 	p2 = compat_expr ?
365 	    exp3(vp, ignore) :
366 	    exp3a(vp, ignore);
367 	cleanup_push(p2, xfree);
368 	etracc("exp3 p2", p2, vp);
369 	if (!(ignore & TEXP_IGNORE))
370 	    switch (i) {
371 
372 	    case GTR:
373 		i = egetn(p1) > egetn(p2);
374 		break;
375 
376 	    case GTR | 1:
377 		i = egetn(p1) >= egetn(p2);
378 		break;
379 
380 	    case LSS:
381 		i = egetn(p1) < egetn(p2);
382 		break;
383 
384 	    case LSS | 1:
385 		i = egetn(p1) <= egetn(p2);
386 		break;
387 	    }
388 	cleanup_until(p1);
389 	p1 = putn(i);
390 	etracc("exp3 p1", p1, vp);
391 	if (compat_expr)
392 	    break;
393     }
394     return (p1);
395 }
396 
397 static Char *
398 exp3a(Char ***vp, int ignore)
399 {
400     Char *p1, *p2;
401     const Char *op;
402     tcsh_number_t i;
403 
404     p1 = exp4(vp, ignore);
405     etracc("exp3a p1", p1, vp);
406     op = **vp;
407     if (op && any("<>", op[0]) && op[0] == op[1]) {
408 	(*vp)++;
409 	cleanup_push(p1, xfree);
410 	p2 = compat_expr ?
411 	    exp3a(vp, ignore) :
412 	    exp4(vp, ignore);
413 	cleanup_push(p2, xfree);
414 	etracc("exp3a p2", p2, vp);
415 	if (op[0] == '<')
416 	    i = egetn(p1) << egetn(p2);
417 	else
418 	    i = egetn(p1) >> egetn(p2);
419 	cleanup_until(p1);
420 	p1 = putn(i);
421 	etracc("exp3a p1", p1, vp);
422     }
423     return (p1);
424 }
425 
426 static Char *
427 exp4(Char ***vp, int ignore)
428 {
429     Char *p1, *p2;
430     tcsh_number_t i = 0;
431 
432     p1 = exp5(vp, ignore);
433     etracc("exp4 p1", p1, vp);
434     while (isa(**vp, ADDOP)) {
435 	const Char *op = *(*vp)++;
436 
437 	cleanup_push(p1, xfree);
438 	p2 = compat_expr ?
439 	    exp4(vp, ignore) :
440 	    exp5(vp, ignore);
441 	cleanup_push(p2, xfree);
442 	etracc("exp4 p2", p2, vp);
443 	if (!(ignore & TEXP_IGNORE))
444 	    switch (op[0]) {
445 
446 	    case '+':
447 		i = egetn(p1) + egetn(p2);
448 		break;
449 
450 	    case '-':
451 		i = egetn(p1) - egetn(p2);
452 		break;
453 	    }
454 	cleanup_until(p1);
455 	p1 = putn(i);
456 	etracc("exp4 p1", p1, vp);
457 	if (compat_expr)
458 	    break;
459     }
460     return (p1);
461 }
462 
463 static Char *
464 exp5(Char ***vp, int ignore)
465 {
466     Char *p1, *p2;
467     tcsh_number_t i = 0;
468 
469     p1 = exp6(vp, ignore);
470     etracc("exp5 p1", p1, vp);
471 
472     while (isa(**vp, MULOP)) {
473 	const Char *op = *(*vp)++;
474 	if ((ignore & TEXP_NOGLOB) != 0) {
475 	    /*
476 	     * We are just trying to get the right side of
477 	     * a =~ or !~ operator
478 	     */
479 	    xfree(p1);
480 	    return Strsave(op);
481 	}
482 
483 	cleanup_push(p1, xfree);
484 	p2 = compat_expr ?
485 	    exp5(vp, ignore) :
486 	    exp6(vp, ignore);
487 	cleanup_push(p2, xfree);
488 	etracc("exp5 p2", p2, vp);
489 	if (!(ignore & TEXP_IGNORE))
490 	    switch (op[0]) {
491 
492 	    case '*':
493 		i = egetn(p1) * egetn(p2);
494 		break;
495 
496 	    case '/':
497 		i = egetn(p2);
498 		if (i == 0)
499 		    stderror(ERR_DIV0);
500 		i = egetn(p1) / i;
501 		break;
502 
503 	    case '%':
504 		i = egetn(p2);
505 		if (i == 0)
506 		    stderror(ERR_MOD0);
507 		i = egetn(p1) % i;
508 		break;
509 	    }
510 	cleanup_until(p1);
511 	p1 = putn(i);
512 	etracc("exp5 p1", p1, vp);
513 	if (compat_expr)
514 	    break;
515     }
516     return (p1);
517 }
518 
519 static Char *
520 exp6(Char ***vp, int ignore)
521 {
522     tcsh_number_t ccode;
523     tcsh_number_t i = 0;
524     Char *cp;
525 
526     if (**vp == 0)
527 	stderror(ERR_NAME | ERR_EXPRESSION);
528     if (eq(**vp, STRbang)) {
529 	(*vp)++;
530 	cp = exp6(vp, ignore);
531 	cleanup_push(cp, xfree);
532 	etracc("exp6 ! cp", cp, vp);
533 	i = egetn(cp);
534 	cleanup_until(cp);
535 	return (putn(!i));
536     }
537     if (eq(**vp, STRtilde)) {
538 	(*vp)++;
539 	cp = exp6(vp, ignore);
540 	cleanup_push(cp, xfree);
541 	etracc("exp6 ~ cp", cp, vp);
542 	i = egetn(cp);
543 	cleanup_until(cp);
544 	return (putn(~i));
545     }
546     if (eq(**vp, STRLparen)) {
547 	(*vp)++;
548 	ccode = exp0(vp, ignore);
549 	etraci("exp6 () ccode", ccode, vp);
550 	if (**vp == 0 || ***vp != ')')
551 	    stderror(ERR_NAME | ERR_EXPRESSION);
552 	(*vp)++;
553 	return (putn(ccode));
554     }
555     if (eq(**vp, STRLbrace)) {
556 	Char **v;
557 	struct command faket;
558 	Char   *fakecom[2];
559 
560 	faket.t_dtyp = NODE_COMMAND;
561 	faket.t_dflg = F_BACKQ;
562 	faket.t_dcar = faket.t_dcdr = faket.t_dspr = NULL;
563 	faket.t_dcom = fakecom;
564 	fakecom[0] = STRfakecom;
565 	fakecom[1] = NULL;
566 	(*vp)++;
567 	v = *vp;
568 	for (;;) {
569 	    if (!**vp)
570 		stderror(ERR_NAME | ERR_MISSING, '}');
571 	    if (eq(*(*vp)++, STRRbrace))
572 		break;
573 	}
574 	if (ignore & TEXP_IGNORE)
575 	    return (Strsave(STRNULL));
576 	psavejob();
577 	cleanup_push(&faket, psavejob_cleanup); /* faket is only a marker */
578 	if (pfork(&faket, -1) == 0) {
579 	    *--(*vp) = 0;
580 	    evalav(v);
581 	    exitstat();
582 	}
583 	pwait();
584 	cleanup_until(&faket);
585 	etraci("exp6 {} status", egetn(varval(STRstatus)), vp);
586 	return (putn(egetn(varval(STRstatus)) == 0));
587     }
588     if (isa(**vp, ANYOP))
589 	return (Strsave(STRNULL));
590     cp = *(*vp)++;
591 #ifdef convex
592 # define FILETESTS "erwxfdzoplstSXLbcugkmKR"
593 #else
594 # define FILETESTS "erwxfdzoplstSXLbcugkmK"
595 #endif /* convex */
596 #define FILEVALS  "ZAMCDIUGNFPL"
597     if (*cp == '-' && (any(FILETESTS, cp[1]) || any(FILEVALS, cp[1])))
598         return(filetest(cp, vp, ignore));
599     etracc("exp6 default", cp, vp);
600     return (ignore & TEXP_NOGLOB ? Strsave(cp) : globone(cp, G_APPEND));
601 }
602 
603 
604 /*
605  * Extended file tests
606  * From: John Rowe <rowe@excc.exeter.ac.uk>
607  */
608 Char *
609 filetest(Char *cp, Char ***vp, int ignore)
610 {
611 #ifdef convex
612     struct cvxstat stb, *st = NULL;
613 # define TCSH_STAT	stat64
614 #else
615 # define TCSH_STAT	stat
616     struct stat stb, *st = NULL;
617 #endif /* convex */
618 
619 #ifdef S_IFLNK
620 # ifdef convex
621     struct cvxstat lstb, *lst = NULL;
622 #  define TCSH_LSTAT lstat64
623 # else
624 #  define TCSH_LSTAT lstat
625     struct stat lstb, *lst = NULL;
626 # endif /* convex */
627     char *filnam;
628 #endif /* S_IFLNK */
629 
630     tcsh_number_t i = 0;
631     unsigned pmask = 0xffff;
632     int altout = 0;
633     Char *ft = cp, *dp, *ep, *strdev, *strino, *strF, *str, valtest = '\0',
634     *errval = STR0;
635     char *string, string0[22 + MB_LEN_MAX + 1];	// space for 64 bit octal
636     time_t footime;
637     struct passwd *pw;
638     struct group *gr;
639 
640     while(any(FILETESTS, *++ft))
641 	continue;
642 
643     if (!*ft && *(ft - 1) == 'L')
644 	--ft;
645 
646     if (any(FILEVALS, *ft)) {
647 	valtest = *ft++;
648 	/*
649 	 * Value tests return '-1' on failure as 0 is
650 	 * a legitimate value for many of them.
651 	 * 'F' returns ':' for compatibility.
652 	 */
653 	errval = valtest == 'F' ? STRcolon : STRminus1;
654 
655 	if (valtest == 'P' && *ft >= '0' && *ft <= '7') {
656 	    pmask = (char) *ft - '0';
657 	    while ( *++ft >= '0' && *ft <= '7' )
658 		pmask = 8 * pmask + ((char) *ft - '0');
659 	}
660 	if (Strcmp(ft, STRcolon) == 0 && any("AMCUGP", valtest)) {
661 	    altout = 1;
662 	    ++ft;
663 	}
664     }
665 
666     if (*ft || ft == cp + 1)
667 	stderror(ERR_NAME | ERR_FILEINQ);
668 
669     /*
670      * Detect missing file names by checking for operator in the file name
671      * position.  However, if an operator name appears there, we must make
672      * sure that there's no file by that name (e.g., "/") before announcing
673      * an error.  Even this check isn't quite right, since it doesn't take
674      * globbing into account.
675      */
676 
677     if (isa(**vp, ANYOP) && TCSH_STAT(short2str(**vp), &stb))
678 	stderror(ERR_NAME | ERR_FILENAME);
679 
680     dp = *(*vp)++;
681     if (ignore & TEXP_IGNORE)
682 	return (Strsave(STRNULL));
683     ep = globone(dp, G_APPEND);
684     cleanup_push(ep, xfree);
685     ft = &cp[1];
686     do
687 	switch (*ft) {
688 
689 	case 'r':
690 	    i = !sh_access(ep, R_OK);
691 	    break;
692 
693 	case 'w':
694 	    i = !sh_access(ep, W_OK);
695 	    break;
696 
697 	case 'x':
698 	    i = !sh_access(ep, X_OK);
699 	    break;
700 
701 	case 'X':	/* tcsh extension, name is an executable in the path
702 			 * or a tcsh builtin command
703 			 */
704 	    i = find_cmd(ep, 0);
705 	    break;
706 
707 	case 't':	/* SGI extension, true when file is a tty */
708 	    i = isatty(atoi(short2str(ep)));
709 	    break;
710 
711 	default:
712 
713 #ifdef S_IFLNK
714 	    if (tolower(*ft) == 'l') {
715 		/*
716 		 * avoid convex compiler bug.
717 		 */
718 		if (!lst) {
719 		    lst = &lstb;
720 		    if (TCSH_LSTAT(short2str(ep), lst) == -1) {
721 			cleanup_until(ep);
722 			return (Strsave(errval));
723 		    }
724 		}
725 		if (*ft == 'L')
726 		    st = lst;
727 	    }
728 	    else
729 #endif /* S_IFLNK */
730 		/*
731 		 * avoid convex compiler bug.
732 		 */
733 		if (!st) {
734 		    st = &stb;
735 		    if (TCSH_STAT(short2str(ep), st) == -1) {
736 			cleanup_until(ep);
737 			return (Strsave(errval));
738 		    }
739 		}
740 
741 	    switch (*ft) {
742 
743 	    case 'f':
744 #ifdef S_ISREG
745 		i = S_ISREG(st->st_mode);
746 #else /* !S_ISREG */
747 		i = 0;
748 #endif /* S_ISREG */
749 		break;
750 
751 	    case 'd':
752 #ifdef S_ISDIR
753 		i = S_ISDIR(st->st_mode);
754 #else /* !S_ISDIR */
755 		i = 0;
756 #endif /* S_ISDIR */
757 		break;
758 
759 	    case 'p':
760 #ifdef S_ISFIFO
761 		i = S_ISFIFO(st->st_mode);
762 #else /* !S_ISFIFO */
763 		i = 0;
764 #endif /* S_ISFIFO */
765 		break;
766 
767 	    case 'm' :
768 #ifdef S_ISOFL
769 	      i = S_ISOFL(st->st_dm_mode);
770 #else /* !S_ISOFL */
771 	      i = 0;
772 #endif /* S_ISOFL */
773 	      break ;
774 
775 	    case 'K' :
776 #ifdef S_ISOFL
777 	      i = stb.st_dm_key;
778 #else /* !S_ISOFL */
779 	      i = 0;
780 #endif /* S_ISOFL */
781 	      break ;
782 
783 
784 	    case 'l':
785 #ifdef S_ISLNK
786 		i = S_ISLNK(lst->st_mode);
787 #else /* !S_ISLNK */
788 		i = 0;
789 #endif /* S_ISLNK */
790 		break;
791 
792 	    case 'S':
793 # ifdef S_ISSOCK
794 		i = S_ISSOCK(st->st_mode);
795 # else /* !S_ISSOCK */
796 		i = 0;
797 # endif /* S_ISSOCK */
798 		break;
799 
800 	    case 'b':
801 #ifdef S_ISBLK
802 		i = S_ISBLK(st->st_mode);
803 #else /* !S_ISBLK */
804 		i = 0;
805 #endif /* S_ISBLK */
806 		break;
807 
808 	    case 'c':
809 #ifdef S_ISCHR
810 		i = S_ISCHR(st->st_mode);
811 #else /* !S_ISCHR */
812 		i = 0;
813 #endif /* S_ISCHR */
814 		break;
815 
816 	    case 'u':
817 		i = (S_ISUID & st->st_mode) != 0;
818 		break;
819 
820 	    case 'g':
821 		i = (S_ISGID & st->st_mode) != 0;
822 		break;
823 
824 	    case 'k':
825 		i = (S_ISVTX & st->st_mode) != 0;
826 		break;
827 
828 	    case 'z':
829 		i = st->st_size == 0;
830 		break;
831 
832 #ifdef convex
833 	    case 'R':
834 		i = (stb.st_dmonflags & IMIGRATED) == IMIGRATED;
835 		break;
836 #endif /* convex */
837 
838 	    case 's':
839 		i = stb.st_size != 0;
840 		break;
841 
842 	    case 'e':
843 		i = 1;
844 		break;
845 
846 	    case 'o':
847 		i = st->st_uid == uid;
848 		break;
849 
850 		/*
851 		 * Value operators are a tcsh extension.
852 		 */
853 
854 	    case 'D':
855 		i = (tcsh_number_t) st->st_dev;
856 		break;
857 
858 	    case 'I':
859 		i = (tcsh_number_t) st->st_ino;
860 		break;
861 
862 	    case 'F':
863 		strdev = putn( (int) st->st_dev);
864 		strino = putn( (int) st->st_ino);
865 		strF = xmalloc((2 + Strlen(strdev) + Strlen(strino))
866 			       * sizeof(Char));
867 		(void) Strcat(Strcat(Strcpy(strF, strdev), STRcolon), strino);
868 		xfree(strdev);
869 		xfree(strino);
870 		cleanup_until(ep);
871 		return(strF);
872 
873 	    case 'L':
874 		if ( *(ft + 1) ) {
875 		    i = 1;
876 		    break;
877 		}
878 #ifdef S_ISLNK
879 		filnam = short2str(ep);
880 		string = areadlink(filnam);
881 		strF = string == NULL ? errval : str2short(string);
882 		xfree(string);
883 		cleanup_until(ep);
884 		return(Strsave(strF));
885 
886 #else /* !S_ISLNK */
887 		i = 0;
888 		break;
889 #endif /* S_ISLNK */
890 
891 
892 	    case 'N':
893 		i = (tcsh_number_t) st->st_nlink;
894 		break;
895 
896 	    case 'P':
897 		string = string0 + 1;
898 		(void) xsnprintf(string, sizeof(string0) - 1, "%o",
899 		    pmask & (unsigned int)
900 		    ((S_IRWXU|S_IRWXG|S_IRWXO|S_ISUID|S_ISGID) & st->st_mode));
901 		if (altout && *string != '0')
902 		    *--string = '0';
903 		cleanup_until(ep);
904 		return(Strsave(str2short(string)));
905 
906 	    case 'U':
907 		if (altout && (pw = xgetpwuid(st->st_uid))) {
908 		    cleanup_until(ep);
909 		    return(Strsave(str2short(pw->pw_name)));
910 		}
911 		i = (tcsh_number_t) st->st_uid;
912 		break;
913 
914 	    case 'G':
915 		if (altout && (gr = xgetgrgid(st->st_gid))) {
916 		    cleanup_until(ep);
917 		    return(Strsave(str2short(gr->gr_name)));
918 		}
919 		i = (tcsh_number_t) st->st_gid;
920 		break;
921 
922 	    case 'Z':
923 		i = (tcsh_number_t) st->st_size;
924 		break;
925 
926 	    case 'A': case 'M': case 'C':
927 		footime = *ft == 'A' ? st->st_atime :
928 		    *ft == 'M' ? st->st_mtime : st->st_ctime;
929 		if (altout) {
930 		    strF = str2short(ctime(&footime));
931 		    if ((str = Strchr(strF, '\n')) != NULL)
932 			*str = (Char) '\0';
933 		    cleanup_until(ep);
934 		    return(Strsave(strF));
935 		}
936 		i = (tcsh_number_t) footime;
937 		break;
938 
939 	    }
940 	}
941     while (*++ft && i);
942     etraci("exp6 -? i", i, vp);
943     cleanup_until(ep);
944     return (putn(i));
945 }
946 
947 
948 static void
949 evalav(Char **v)
950 {
951     struct wordent paraml1;
952     struct wordent *hp = &paraml1;
953     struct command *t;
954     struct wordent *wdp = hp;
955 
956     setcopy(STRstatus, STR0, VAR_READWRITE);
957     hp->prev = hp->next = hp;
958     hp->word = STRNULL;
959     while (*v) {
960 	struct wordent *new = xcalloc(1, sizeof *wdp);
961 
962 	new->prev = wdp;
963 	new->next = hp;
964 	wdp->next = new;
965 	wdp = new;
966 	wdp->word = Strsave(*v++);
967     }
968     hp->prev = wdp;
969     cleanup_push(&paraml1, lex_cleanup);
970     alias(&paraml1);
971     t = syntax(paraml1.next, &paraml1, 0);
972     cleanup_push(t, syntax_cleanup);
973     if (seterr)
974 	stderror(ERR_OLD);
975     execute(t, -1, NULL, NULL, TRUE);
976     cleanup_until(&paraml1);
977 }
978 
979 static int
980 isa(Char *cp, int what)
981 {
982     if (cp == 0)
983 	return ((what & RESTOP) != 0);
984     if (*cp == '\0')
985     	return 0;
986     if (cp[1] == 0) {
987 	if (what & ADDOP && (*cp == '+' || *cp == '-'))
988 	    return (1);
989 	if (what & MULOP && (*cp == '*' || *cp == '/' || *cp == '%'))
990 	    return (1);
991 	if (what & RESTOP && (*cp == '(' || *cp == ')' || *cp == '!' ||
992 			      *cp == '~' || *cp == '^' || *cp == '"'))
993 	    return (1);
994     }
995     else if (cp[2] == 0) {
996 	if (what & RESTOP) {
997 	    if (cp[0] == '|' && cp[1] == '&')
998 		return (1);
999 	    if (cp[0] == '<' && cp[1] == '<')
1000 		return (1);
1001 	    if (cp[0] == '>' && cp[1] == '>')
1002 		return (1);
1003 	}
1004 	if (what & EQOP) {
1005 	    if (cp[0] == '=') {
1006 		if (cp[1] == '=')
1007 		    return (EQEQ);
1008 		if (cp[1] == '~')
1009 		    return (EQMATCH);
1010 	    }
1011 	    else if (cp[0] == '!') {
1012 		if (cp[1] == '=')
1013 		    return (NOTEQ);
1014 		if (cp[1] == '~')
1015 		    return (NOTEQMATCH);
1016 	    }
1017 	}
1018     }
1019     if (what & RELOP) {
1020 	if (*cp == '<')
1021 	    return (LSS);
1022 	if (*cp == '>')
1023 	    return (GTR);
1024     }
1025     return (0);
1026 }
1027 
1028 static tcsh_number_t
1029 egetn(const Char *cp)
1030 {
1031     if (*cp && *cp != '-' && !Isdigit(*cp))
1032 	stderror(ERR_NAME | ERR_EXPRESSION);
1033     return (getn(cp));
1034 }
1035 
1036 /* Phew! */
1037 
1038 #ifdef EDEBUG
1039 static void
1040 etraci(const char *str, tcsh_number_t i, Char ***vp)
1041 {
1042 #ifdef HAVE_LONG_LONG
1043     xprintf("%s=%lld\t", str, i);
1044 #else
1045     xprintf("%s=%ld\t", str, i);
1046 #endif
1047     blkpr(*vp);
1048     xputchar('\n');
1049 }
1050 static void
1051 etracc(const char *str, const Char *cp, Char ***vp)
1052 {
1053     xprintf("%s=%S\t", str, cp);
1054     blkpr(*vp);
1055     xputchar('\n');
1056 }
1057 #endif /* EDEBUG */
1058