xref: /freebsd/contrib/less/filename.c (revision d056fa046c6a91b90cd98165face0e42a33a5173)
1 /*
2  * Copyright (C) 1984-2002  Mark Nudelman
3  *
4  * You may distribute under the terms of either the GNU General Public
5  * License or the Less License, as specified in the README file.
6  *
7  * For more information about less, or for information on how to
8  * contact the author, see the README file.
9  */
10 
11 
12 /*
13  * Routines to mess around with filenames (and files).
14  * Much of this is very OS dependent.
15  */
16 
17 #include "less.h"
18 #include "lglob.h"
19 #if MSDOS_COMPILER
20 #include <dos.h>
21 #if MSDOS_COMPILER==WIN32C && !defined(_MSC_VER)
22 #include <dir.h>
23 #endif
24 #if MSDOS_COMPILER==DJGPPC
25 #include <glob.h>
26 #include <dir.h>
27 #define _MAX_PATH	PATH_MAX
28 #endif
29 #endif
30 #ifdef _OSK
31 #include <rbf.h>
32 #ifndef _OSK_MWC32
33 #include <modes.h>
34 #endif
35 #endif
36 #if OS2
37 #include <signal.h>
38 #endif
39 
40 #if HAVE_STAT
41 #include <sys/stat.h>
42 #ifndef S_ISDIR
43 #define	S_ISDIR(m)	(((m) & S_IFMT) == S_IFDIR)
44 #endif
45 #ifndef S_ISREG
46 #define	S_ISREG(m)	(((m) & S_IFMT) == S_IFREG)
47 #endif
48 #endif
49 
50 
51 extern int force_open;
52 extern int secure;
53 extern int use_lessopen;
54 extern IFILE curr_ifile;
55 extern IFILE old_ifile;
56 #if SPACES_IN_FILENAMES
57 extern char openquote;
58 extern char closequote;
59 #endif
60 
61 /*
62  * Remove quotes around a filename.
63  */
64 	public char *
65 shell_unquote(str)
66 	char *str;
67 {
68 	char *name;
69 	char *p;
70 
71 	name = p = (char *) ecalloc(strlen(str)+1, sizeof(char));
72 	if (*str == openquote)
73 	{
74 		str++;
75 		while (*str != '\0')
76 		{
77 			if (*str == closequote)
78 			{
79 				if (str[1] != closequote)
80 					break;
81 				str++;
82 			}
83 			*p++ = *str++;
84 		}
85 	} else
86 	{
87 		char *esc = get_meta_escape();
88 		int esclen = strlen(esc);
89 		while (*str != '\0')
90 		{
91 			if (esclen > 0 && strncmp(str, esc, esclen) == 0)
92 				str += esclen;
93 			*p++ = *str++;
94 		}
95 	}
96 	*p = '\0';
97 	return (name);
98 }
99 
100 /*
101  * Get the shell's escape character.
102  */
103 	public char *
104 get_meta_escape()
105 {
106 	char *s;
107 
108 	s = lgetenv("LESSMETAESCAPE");
109 	if (s == NULL)
110 		s = DEF_METAESCAPE;
111 	return (s);
112 }
113 
114 /*
115  * Get the characters which the shell considers to be "metacharacters".
116  */
117 	static char *
118 metachars()
119 {
120 	static char *mchars = NULL;
121 
122 	if (mchars == NULL)
123 	{
124 		mchars = lgetenv("LESSMETACHARS");
125 		if (mchars == NULL)
126 			mchars = DEF_METACHARS;
127 	}
128 	return (mchars);
129 }
130 
131 /*
132  * Is this a shell metacharacter?
133  */
134 	static int
135 metachar(c)
136 	char c;
137 {
138 	return (strchr(metachars(), c) != NULL);
139 }
140 
141 /*
142  * Insert a backslash before each metacharacter in a string.
143  */
144 	public char *
145 shell_quote(s)
146 	char *s;
147 {
148 	char *p;
149 	char *newstr;
150 	int len;
151 	char *esc = get_meta_escape();
152 	int esclen = strlen(esc);
153 	int use_quotes = 0;
154 	int have_quotes = 0;
155 
156 	/*
157 	 * Determine how big a string we need to allocate.
158 	 */
159 	len = 1; /* Trailing null byte */
160 	for (p = s;  *p != '\0';  p++)
161 	{
162 		len++;
163 		if (*p == openquote || *p == closequote)
164 			have_quotes = 1;
165 		if (metachar(*p))
166 		{
167 			if (esclen == 0)
168 			{
169 				/*
170 				 * We've got a metachar, but this shell
171 				 * doesn't support escape chars.  Use quotes.
172 				 */
173 				use_quotes = 1;
174 			} else
175 			{
176 				/*
177 				 * Allow space for the escape char.
178 				 */
179 				len += esclen;
180 			}
181 		}
182 	}
183 	if (use_quotes)
184 	{
185 		if (have_quotes)
186 			/*
187 			 * We can't quote a string that contains quotes.
188 			 */
189 			return (NULL);
190 		len = strlen(s) + 3;
191 	}
192 	/*
193 	 * Allocate and construct the new string.
194 	 */
195 	newstr = p = (char *) ecalloc(len, sizeof(char));
196 	if (use_quotes)
197 	{
198 		sprintf(newstr, "%c%s%c", openquote, s, closequote);
199 	} else
200 	{
201 		while (*s != '\0')
202 		{
203 			if (metachar(*s))
204 			{
205 				/*
206 				 * Add the escape char.
207 				 */
208 				strcpy(p, esc);
209 				p += esclen;
210 			}
211 			*p++ = *s++;
212 		}
213 		*p = '\0';
214 	}
215 	return (newstr);
216 }
217 
218 /*
219  * Return a pathname that points to a specified file in a specified directory.
220  * Return NULL if the file does not exist in the directory.
221  */
222 	static char *
223 dirfile(dirname, filename)
224 	char *dirname;
225 	char *filename;
226 {
227 	char *pathname;
228 	char *qpathname;
229 	int f;
230 
231 	if (dirname == NULL || *dirname == '\0')
232 		return (NULL);
233 	/*
234 	 * Construct the full pathname.
235 	 */
236 	pathname = (char *) calloc(strlen(dirname) + strlen(filename) + 2,
237 					sizeof(char));
238 	if (pathname == NULL)
239 		return (NULL);
240 	sprintf(pathname, "%s%s%s", dirname, PATHNAME_SEP, filename);
241 	/*
242 	 * Make sure the file exists.
243 	 */
244 	qpathname = shell_unquote(pathname);
245 	f = open(qpathname, OPEN_READ);
246 	if (f < 0)
247 	{
248 		free(pathname);
249 		pathname = NULL;
250 	} else
251 	{
252 		close(f);
253 	}
254 	free(qpathname);
255 	return (pathname);
256 }
257 
258 /*
259  * Return the full pathname of the given file in the "home directory".
260  */
261 	public char *
262 homefile(filename)
263 	char *filename;
264 {
265 	register char *pathname;
266 
267 	/*
268 	 * Try $HOME/filename.
269 	 */
270 	pathname = dirfile(lgetenv("HOME"), filename);
271 	if (pathname != NULL)
272 		return (pathname);
273 #if OS2
274 	/*
275 	 * Try $INIT/filename.
276 	 */
277 	pathname = dirfile(lgetenv("INIT"), filename);
278 	if (pathname != NULL)
279 		return (pathname);
280 #endif
281 #if MSDOS_COMPILER || OS2
282 	/*
283 	 * Look for the file anywhere on search path.
284 	 */
285 	pathname = (char *) calloc(_MAX_PATH, sizeof(char));
286 #if MSDOS_COMPILER==DJGPPC
287 	{
288 		char *res = searchpath(filename);
289 		if (res == 0)
290 			*pathname = '\0';
291 		else
292 			strcpy(pathname, res);
293 	}
294 #else
295 	_searchenv(filename, "PATH", pathname);
296 #endif
297 	if (*pathname != '\0')
298 		return (pathname);
299 	free(pathname);
300 #endif
301 	return (NULL);
302 }
303 
304 /*
305  * Expand a string, substituting any "%" with the current filename,
306  * and any "#" with the previous filename.
307  * But a string of N "%"s is just replaced with N-1 "%"s.
308  * Likewise for a string of N "#"s.
309  * {{ This is a lot of work just to support % and #. }}
310  */
311 	public char *
312 fexpand(s)
313 	char *s;
314 {
315 	register char *fr, *to;
316 	register int n;
317 	register char *e;
318 	IFILE ifile;
319 
320 #define	fchar_ifile(c) \
321 	((c) == '%' ? curr_ifile : \
322 	 (c) == '#' ? old_ifile : NULL_IFILE)
323 
324 	/*
325 	 * Make one pass to see how big a buffer we
326 	 * need to allocate for the expanded string.
327 	 */
328 	n = 0;
329 	for (fr = s;  *fr != '\0';  fr++)
330 	{
331 		switch (*fr)
332 		{
333 		case '%':
334 		case '#':
335 			if (fr > s && fr[-1] == *fr)
336 			{
337 				/*
338 				 * Second (or later) char in a string
339 				 * of identical chars.  Treat as normal.
340 				 */
341 				n++;
342 			} else if (fr[1] != *fr)
343 			{
344 				/*
345 				 * Single char (not repeated).  Treat specially.
346 				 */
347 				ifile = fchar_ifile(*fr);
348 				if (ifile == NULL_IFILE)
349 					n++;
350 				else
351 					n += strlen(get_filename(ifile));
352 			}
353 			/*
354 			 * Else it is the first char in a string of
355 			 * identical chars.  Just discard it.
356 			 */
357 			break;
358 		default:
359 			n++;
360 			break;
361 		}
362 	}
363 
364 	e = (char *) ecalloc(n+1, sizeof(char));
365 
366 	/*
367 	 * Now copy the string, expanding any "%" or "#".
368 	 */
369 	to = e;
370 	for (fr = s;  *fr != '\0';  fr++)
371 	{
372 		switch (*fr)
373 		{
374 		case '%':
375 		case '#':
376 			if (fr > s && fr[-1] == *fr)
377 			{
378 				*to++ = *fr;
379 			} else if (fr[1] != *fr)
380 			{
381 				ifile = fchar_ifile(*fr);
382 				if (ifile == NULL_IFILE)
383 					*to++ = *fr;
384 				else
385 				{
386 					strcpy(to, get_filename(ifile));
387 					to += strlen(to);
388 				}
389 			}
390 			break;
391 		default:
392 			*to++ = *fr;
393 			break;
394 		}
395 	}
396 	*to = '\0';
397 	return (e);
398 }
399 
400 #if TAB_COMPLETE_FILENAME
401 
402 /*
403  * Return a blank-separated list of filenames which "complete"
404  * the given string.
405  */
406 	public char *
407 fcomplete(s)
408 	char *s;
409 {
410 	char *fpat;
411 	char *qs;
412 
413 	if (secure)
414 		return (NULL);
415 	/*
416 	 * Complete the filename "s" by globbing "s*".
417 	 */
418 #if MSDOS_COMPILER && (MSDOS_COMPILER == MSOFTC || MSDOS_COMPILER == BORLANDC)
419 	/*
420 	 * But in DOS, we have to glob "s*.*".
421 	 * But if the final component of the filename already has
422 	 * a dot in it, just do "s*".
423 	 * (Thus, "FILE" is globbed as "FILE*.*",
424 	 *  but "FILE.A" is globbed as "FILE.A*").
425 	 */
426 	{
427 		char *slash;
428 		for (slash = s+strlen(s)-1;  slash > s;  slash--)
429 			if (*slash == *PATHNAME_SEP || *slash == '/')
430 				break;
431 		fpat = (char *) ecalloc(strlen(s)+4, sizeof(char));
432 		if (strchr(slash, '.') == NULL)
433 			sprintf(fpat, "%s*.*", s);
434 		else
435 			sprintf(fpat, "%s*", s);
436 	}
437 #else
438 	fpat = (char *) ecalloc(strlen(s)+2, sizeof(char));
439 	sprintf(fpat, "%s*", s);
440 #endif
441 	qs = lglob(fpat);
442 	s = shell_unquote(qs);
443 	if (strcmp(s,fpat) == 0)
444 	{
445 		/*
446 		 * The filename didn't expand.
447 		 */
448 		free(qs);
449 		qs = NULL;
450 	}
451 	free(s);
452 	free(fpat);
453 	return (qs);
454 }
455 #endif
456 
457 /*
458  * Try to determine if a file is "binary".
459  * This is just a guess, and we need not try too hard to make it accurate.
460  */
461 	public int
462 bin_file(f)
463 	int f;
464 {
465 	int i;
466 	int n;
467 	unsigned char data[64];
468 
469 	if (!seekable(f))
470 		return (0);
471 	if (lseek(f, (off_t)0, 0) == BAD_LSEEK)
472 		return (0);
473 	n = read(f, data, sizeof(data));
474 	for (i = 0;  i < n;  i++)
475 		if (binary_char(data[i]))
476 			return (1);
477 	return (0);
478 }
479 
480 /*
481  * Try to determine the size of a file by seeking to the end.
482  */
483 	static POSITION
484 seek_filesize(f)
485 	int f;
486 {
487 	off_t spos;
488 
489 	spos = lseek(f, (off_t)0, 2);
490 	if (spos == BAD_LSEEK)
491 		return (NULL_POSITION);
492 	return ((POSITION) spos);
493 }
494 
495 /*
496  * Read a string from a file.
497  * Return a pointer to the string in memory.
498  */
499 	static char *
500 readfd(fd)
501 	FILE *fd;
502 {
503 	int len;
504 	int ch;
505 	char *buf;
506 	char *p;
507 
508 	/*
509 	 * Make a guess about how many chars in the string
510 	 * and allocate a buffer to hold it.
511 	 */
512 	len = 100;
513 	buf = (char *) ecalloc(len, sizeof(char));
514 	for (p = buf;  ;  p++)
515 	{
516 		if ((ch = getc(fd)) == '\n' || ch == EOF)
517 			break;
518 		if (p - buf >= len-1)
519 		{
520 			/*
521 			 * The string is too big to fit in the buffer we have.
522 			 * Allocate a new buffer, twice as big.
523 			 */
524 			len *= 2;
525 			*p = '\0';
526 			p = (char *) ecalloc(len, sizeof(char));
527 			strcpy(p, buf);
528 			free(buf);
529 			buf = p;
530 			p = buf + strlen(buf);
531 		}
532 		*p = ch;
533 	}
534 	*p = '\0';
535 	return (buf);
536 }
537 
538 
539 
540 #if HAVE_POPEN
541 
542 FILE *popen();
543 
544 /*
545  * Execute a shell command.
546  * Return a pointer to a pipe connected to the shell command's standard output.
547  */
548 	static FILE *
549 shellcmd(cmd)
550 	char *cmd;
551 {
552 	FILE *fd;
553 
554 #if HAVE_SHELL
555 	char *shell;
556 
557 	shell = lgetenv("SHELL");
558 	if (shell != NULL && *shell != '\0')
559 	{
560 		char *scmd;
561 		char *esccmd;
562 
563 		/*
564 		 * Read the output of <$SHELL -c cmd>.
565 		 * Escape any metacharacters in the command.
566 		 */
567 		esccmd = shell_quote(cmd);
568 		if (esccmd == NULL)
569 		{
570 			fd = popen(cmd, "r");
571 		} else
572 		{
573 			scmd = (char *) ecalloc(strlen(shell) + strlen(esccmd) + 5,
574 						sizeof(char));
575 			sprintf(scmd, "%s %s %s", shell, shell_coption(), esccmd);
576 			free(esccmd);
577 			fd = popen(scmd, "r");
578 			free(scmd);
579 		}
580 	} else
581 #endif
582 	{
583 		fd = popen(cmd, "r");
584 	}
585 	/*
586 	 * Redirection in `popen' might have messed with the
587 	 * standard devices.  Restore binary input mode.
588 	 */
589 	SET_BINARY(0);
590 	return (fd);
591 }
592 
593 #endif /* HAVE_POPEN */
594 
595 
596 /*
597  * Expand a filename, doing any system-specific metacharacter substitutions.
598  */
599 	public char *
600 lglob(filename)
601 	char *filename;
602 {
603 	char *gfilename;
604 	char *ofilename;
605 
606 	ofilename = fexpand(filename);
607 	if (secure)
608 		return (ofilename);
609 	filename = shell_unquote(ofilename);
610 
611 #ifdef DECL_GLOB_LIST
612 {
613 	/*
614 	 * The globbing function returns a list of names.
615 	 */
616 	int length;
617 	char *p;
618 	char *qfilename;
619 	DECL_GLOB_LIST(list)
620 
621 	GLOB_LIST(filename, list);
622 	if (GLOB_LIST_FAILED(list))
623 	{
624 		free(filename);
625 		return (ofilename);
626 	}
627 	length = 1; /* Room for trailing null byte */
628 	for (SCAN_GLOB_LIST(list, p))
629 	{
630 		INIT_GLOB_LIST(list, p);
631 		qfilename = shell_quote(p);
632 		if (qfilename != NULL)
633 		{
634 	  		length += strlen(qfilename) + 1;
635 			free(qfilename);
636 		}
637 	}
638 	gfilename = (char *) ecalloc(length, sizeof(char));
639 	for (SCAN_GLOB_LIST(list, p))
640 	{
641 		INIT_GLOB_LIST(list, p);
642 		qfilename = shell_quote(p);
643 		if (qfilename != NULL)
644 		{
645 			sprintf(gfilename + strlen(gfilename), "%s ", qfilename);
646 			free(qfilename);
647 		}
648 	}
649 	/*
650 	 * Overwrite the final trailing space with a null terminator.
651 	 */
652 	*--p = '\0';
653 	GLOB_LIST_DONE(list);
654 }
655 #else
656 #ifdef DECL_GLOB_NAME
657 {
658 	/*
659 	 * The globbing function returns a single name, and
660 	 * is called multiple times to walk thru all names.
661 	 */
662 	register char *p;
663 	register int len;
664 	register int n;
665 	char *pathname;
666 	char *qpathname;
667 	DECL_GLOB_NAME(fnd,drive,dir,fname,ext,handle)
668 
669 	GLOB_FIRST_NAME(filename, &fnd, handle);
670 	if (GLOB_FIRST_FAILED(handle))
671 	{
672 		free(filename);
673 		return (ofilename);
674 	}
675 
676 	_splitpath(filename, drive, dir, fname, ext);
677 	len = 100;
678 	gfilename = (char *) ecalloc(len, sizeof(char));
679 	p = gfilename;
680 	do {
681 		n = strlen(drive) + strlen(dir) + strlen(fnd.GLOB_NAME) + 1;
682 		pathname = (char *) ecalloc(n, sizeof(char));
683 		sprintf(pathname, "%s%s%s", drive, dir, fnd.GLOB_NAME);
684 		qpathname = shell_quote(pathname);
685 		free(pathname);
686 		if (qpathname != NULL)
687 		{
688 			n = strlen(qpathname);
689 			while (p - gfilename + n + 2 >= len)
690 			{
691 				/*
692 				 * No room in current buffer.
693 				 * Allocate a bigger one.
694 				 */
695 				len *= 2;
696 				*p = '\0';
697 				p = (char *) ecalloc(len, sizeof(char));
698 				strcpy(p, gfilename);
699 				free(gfilename);
700 				gfilename = p;
701 				p = gfilename + strlen(gfilename);
702 			}
703 			strcpy(p, qpathname);
704 			free(qpathname);
705 			p += n;
706 			*p++ = ' ';
707 		}
708 	} while (GLOB_NEXT_NAME(handle, &fnd) == 0);
709 
710 	/*
711 	 * Overwrite the final trailing space with a null terminator.
712 	 */
713 	*--p = '\0';
714 	GLOB_NAME_DONE(handle);
715 }
716 #else
717 #if HAVE_POPEN
718 {
719 	/*
720 	 * We get the shell to glob the filename for us by passing
721 	 * an "echo" command to the shell and reading its output.
722 	 */
723 	FILE *fd;
724 	char *s;
725 	char *lessecho;
726 	char *cmd;
727 	char *esc;
728 
729 	esc = get_meta_escape();
730 	if (strlen(esc) == 0)
731 		esc = "-";
732 	esc = shell_quote(esc);
733 	if (esc == NULL)
734 	{
735 		free(filename);
736 		return (ofilename);
737 	}
738 	lessecho = lgetenv("LESSECHO");
739 	if (lessecho == NULL || *lessecho == '\0')
740 		lessecho = "lessecho";
741 	/*
742 	 * Invoke lessecho, and read its output (a globbed list of filenames).
743 	 */
744 	cmd = (char *) ecalloc(strlen(lessecho) + strlen(ofilename) + (7*strlen(metachars())) + 24, sizeof(char));
745 	sprintf(cmd, "%s -p0x%x -d0x%x -e%s ", lessecho, openquote, closequote, esc);
746 	free(esc);
747 	for (s = metachars();  *s != '\0';  s++)
748 		sprintf(cmd + strlen(cmd), "-n0x%x ", *s);
749 	sprintf(cmd + strlen(cmd), "-- %s", ofilename);
750 	fd = shellcmd(cmd);
751 	free(cmd);
752 	if (fd == NULL)
753 	{
754 		/*
755 		 * Cannot create the pipe.
756 		 * Just return the original (fexpanded) filename.
757 		 */
758 		free(filename);
759 		return (ofilename);
760 	}
761 	gfilename = readfd(fd);
762 	pclose(fd);
763 	if (*gfilename == '\0')
764 	{
765 		free(gfilename);
766 		free(filename);
767 		return (ofilename);
768 	}
769 }
770 #else
771 	/*
772 	 * No globbing functions at all.  Just use the fexpanded filename.
773 	 */
774 	gfilename = save(filename);
775 #endif
776 #endif
777 #endif
778 	free(filename);
779 	free(ofilename);
780 	return (gfilename);
781 }
782 
783 /*
784  * See if we should open a "replacement file"
785  * instead of the file we're about to open.
786  */
787 	public char *
788 open_altfile(filename, pf, pfd)
789 	char *filename;
790 	int *pf;
791 	void **pfd;
792 {
793 #if !HAVE_POPEN
794 	return (NULL);
795 #else
796 	char *lessopen;
797 	char *cmd;
798 	FILE *fd;
799 #if HAVE_FILENO
800 	int returnfd = 0;
801 #endif
802 
803 	if (!use_lessopen || secure)
804 		return (NULL);
805 	ch_ungetchar(-1);
806 	if ((lessopen = lgetenv("LESSOPEN")) == NULL)
807 		return (NULL);
808 	if (strcmp(filename, "-") == 0)
809 		return (NULL);
810 	if (*lessopen == '|')
811 	{
812 		/*
813 		 * If LESSOPEN starts with a |, it indicates
814 		 * a "pipe preprocessor".
815 		 */
816 #if HAVE_FILENO
817 		lessopen++;
818 		returnfd = 1;
819 #else
820 		error("LESSOPEN pipe is not supported", NULL_PARG);
821 		return (NULL);
822 #endif
823 	}
824 
825 	cmd = (char *) ecalloc(strlen(lessopen) + strlen(filename) + 2,
826 			sizeof(char));
827 	sprintf(cmd, lessopen, filename);
828 	fd = shellcmd(cmd);
829 	free(cmd);
830 	if (fd == NULL)
831 	{
832 		/*
833 		 * Cannot create the pipe.
834 		 */
835 		return (NULL);
836 	}
837 #if HAVE_FILENO
838 	if (returnfd)
839 	{
840 		int f;
841 		char c;
842 
843 		/*
844 		 * Read one char to see if the pipe will produce any data.
845 		 * If it does, push the char back on the pipe.
846 		 */
847 		f = fileno(fd);
848 		SET_BINARY(f);
849 		if (read(f, &c, 1) != 1)
850 		{
851 			/*
852 			 * Pipe is empty.  This means there is no alt file.
853 			 */
854 			pclose(fd);
855 			return (NULL);
856 		}
857 		ch_ungetchar(c);
858 		*pfd = (void *) fd;
859 		*pf = f;
860 		return (save("-"));
861 	}
862 #endif
863 	cmd = readfd(fd);
864 	pclose(fd);
865 	if (*cmd == '\0')
866 		/*
867 		 * Pipe is empty.  This means there is no alt file.
868 		 */
869 		return (NULL);
870 	return (cmd);
871 #endif /* HAVE_POPEN */
872 }
873 
874 /*
875  * Close a replacement file.
876  */
877 	public void
878 close_altfile(altfilename, filename, pipefd)
879 	char *altfilename;
880 	char *filename;
881 	void *pipefd;
882 {
883 #if HAVE_POPEN
884 	char *lessclose;
885 	FILE *fd;
886 	char *cmd;
887 
888 	if (secure)
889 		return;
890 	if (pipefd != NULL)
891 	{
892 #if OS2
893 		/*
894 		 * The pclose function of OS/2 emx sometimes fails.
895 		 * Send SIGINT to the piped process before closing it.
896 		 */
897 		kill(((FILE*)pipefd)->_pid, SIGINT);
898 #endif
899 		pclose((FILE*) pipefd);
900 	}
901 	if ((lessclose = lgetenv("LESSCLOSE")) == NULL)
902 	     	return;
903 	cmd = (char *) ecalloc(strlen(lessclose) + strlen(filename) +
904 			strlen(altfilename) + 2, sizeof(char));
905 	sprintf(cmd, lessclose, filename, altfilename);
906 	fd = shellcmd(cmd);
907 	free(cmd);
908 	if (fd != NULL)
909 		pclose(fd);
910 #endif
911 }
912 
913 /*
914  * Is the specified file a directory?
915  */
916 	public int
917 is_dir(filename)
918 	char *filename;
919 {
920 	int isdir = 0;
921 
922 	filename = shell_unquote(filename);
923 #if HAVE_STAT
924 {
925 	int r;
926 	struct stat statbuf;
927 
928 	r = stat(filename, &statbuf);
929 	isdir = (r >= 0 && S_ISDIR(statbuf.st_mode));
930 }
931 #else
932 #ifdef _OSK
933 {
934 	register int f;
935 
936 	f = open(filename, S_IREAD | S_IFDIR);
937 	if (f >= 0)
938 		close(f);
939 	isdir = (f >= 0);
940 }
941 #endif
942 #endif
943 	free(filename);
944 	return (isdir);
945 }
946 
947 /*
948  * Returns NULL if the file can be opened and
949  * is an ordinary file, otherwise an error message
950  * (if it cannot be opened or is a directory, etc.)
951  */
952 	public char *
953 bad_file(filename)
954 	char *filename;
955 {
956 	register char *m = NULL;
957 
958 	filename = shell_unquote(filename);
959 	if (is_dir(filename))
960 	{
961 		static char is_a_dir[] = " is a directory";
962 
963 		m = (char *) ecalloc(strlen(filename) + sizeof(is_a_dir),
964 			sizeof(char));
965 		strcpy(m, filename);
966 		strcat(m, is_a_dir);
967 	} else
968 	{
969 #if HAVE_STAT
970 		int r;
971 		struct stat statbuf;
972 
973 		r = stat(filename, &statbuf);
974 		if (r < 0)
975 		{
976 			m = errno_message(filename);
977 		} else if (force_open)
978 		{
979 			m = NULL;
980 		} else if (!S_ISREG(statbuf.st_mode))
981 		{
982 			static char not_reg[] = " is not a regular file (use -f to see it)";
983 			m = (char *) ecalloc(strlen(filename) + sizeof(not_reg),
984 				sizeof(char));
985 			strcpy(m, filename);
986 			strcat(m, not_reg);
987 		}
988 #endif
989 	}
990 	free(filename);
991 	return (m);
992 }
993 
994 /*
995  * Return the size of a file, as cheaply as possible.
996  * In Unix, we can stat the file.
997  */
998 	public POSITION
999 filesize(f)
1000 	int f;
1001 {
1002 #if HAVE_STAT
1003 	struct stat statbuf;
1004 
1005 	if (fstat(f, &statbuf) >= 0)
1006 		return ((POSITION) statbuf.st_size);
1007 #else
1008 #ifdef _OSK
1009 	long size;
1010 
1011 	if ((size = (long) _gs_size(f)) >= 0)
1012 		return ((POSITION) size);
1013 #endif
1014 #endif
1015 	return (seek_filesize(f));
1016 }
1017 
1018 /*
1019  *
1020  */
1021 	public char *
1022 shell_coption()
1023 {
1024 	return ("-c");
1025 }
1026