xref: /freebsd/contrib/less/filename.c (revision 2b743a9e9ddc6736208dc8ca1ce06ce64ad20a19)
1 /*
2  * Copyright (C) 1984-2005  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 		SNPRINTF3(newstr, len, "%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 len;
230 	int f;
231 
232 	if (dirname == NULL || *dirname == '\0')
233 		return (NULL);
234 	/*
235 	 * Construct the full pathname.
236 	 */
237 	len= strlen(dirname) + strlen(filename) + 2;
238 	pathname = (char *) calloc(len, sizeof(char));
239 	if (pathname == NULL)
240 		return (NULL);
241 	SNPRINTF3(pathname, len, "%s%s%s", dirname, PATHNAME_SEP, filename);
242 	/*
243 	 * Make sure the file exists.
244 	 */
245 	qpathname = shell_unquote(pathname);
246 	f = open(qpathname, OPEN_READ);
247 	if (f < 0)
248 	{
249 		free(pathname);
250 		pathname = NULL;
251 	} else
252 	{
253 		close(f);
254 	}
255 	free(qpathname);
256 	return (pathname);
257 }
258 
259 /*
260  * Return the full pathname of the given file in the "home directory".
261  */
262 	public char *
263 homefile(filename)
264 	char *filename;
265 {
266 	register char *pathname;
267 
268 	/*
269 	 * Try $HOME/filename.
270 	 */
271 	pathname = dirfile(lgetenv("HOME"), filename);
272 	if (pathname != NULL)
273 		return (pathname);
274 #if OS2
275 	/*
276 	 * Try $INIT/filename.
277 	 */
278 	pathname = dirfile(lgetenv("INIT"), filename);
279 	if (pathname != NULL)
280 		return (pathname);
281 #endif
282 #if MSDOS_COMPILER || OS2
283 	/*
284 	 * Look for the file anywhere on search path.
285 	 */
286 	pathname = (char *) calloc(_MAX_PATH, sizeof(char));
287 #if MSDOS_COMPILER==DJGPPC
288 	{
289 		char *res = searchpath(filename);
290 		if (res == 0)
291 			*pathname = '\0';
292 		else
293 			strcpy(pathname, res);
294 	}
295 #else
296 	_searchenv(filename, "PATH", pathname);
297 #endif
298 	if (*pathname != '\0')
299 		return (pathname);
300 	free(pathname);
301 #endif
302 	return (NULL);
303 }
304 
305 /*
306  * Expand a string, substituting any "%" with the current filename,
307  * and any "#" with the previous filename.
308  * But a string of N "%"s is just replaced with N-1 "%"s.
309  * Likewise for a string of N "#"s.
310  * {{ This is a lot of work just to support % and #. }}
311  */
312 	public char *
313 fexpand(s)
314 	char *s;
315 {
316 	register char *fr, *to;
317 	register int n;
318 	register char *e;
319 	IFILE ifile;
320 
321 #define	fchar_ifile(c) \
322 	((c) == '%' ? curr_ifile : \
323 	 (c) == '#' ? old_ifile : NULL_IFILE)
324 
325 	/*
326 	 * Make one pass to see how big a buffer we
327 	 * need to allocate for the expanded string.
328 	 */
329 	n = 0;
330 	for (fr = s;  *fr != '\0';  fr++)
331 	{
332 		switch (*fr)
333 		{
334 		case '%':
335 		case '#':
336 			if (fr > s && fr[-1] == *fr)
337 			{
338 				/*
339 				 * Second (or later) char in a string
340 				 * of identical chars.  Treat as normal.
341 				 */
342 				n++;
343 			} else if (fr[1] != *fr)
344 			{
345 				/*
346 				 * Single char (not repeated).  Treat specially.
347 				 */
348 				ifile = fchar_ifile(*fr);
349 				if (ifile == NULL_IFILE)
350 					n++;
351 				else
352 					n += strlen(get_filename(ifile));
353 			}
354 			/*
355 			 * Else it is the first char in a string of
356 			 * identical chars.  Just discard it.
357 			 */
358 			break;
359 		default:
360 			n++;
361 			break;
362 		}
363 	}
364 
365 	e = (char *) ecalloc(n+1, sizeof(char));
366 
367 	/*
368 	 * Now copy the string, expanding any "%" or "#".
369 	 */
370 	to = e;
371 	for (fr = s;  *fr != '\0';  fr++)
372 	{
373 		switch (*fr)
374 		{
375 		case '%':
376 		case '#':
377 			if (fr > s && fr[-1] == *fr)
378 			{
379 				*to++ = *fr;
380 			} else if (fr[1] != *fr)
381 			{
382 				ifile = fchar_ifile(*fr);
383 				if (ifile == NULL_IFILE)
384 					*to++ = *fr;
385 				else
386 				{
387 					strcpy(to, get_filename(ifile));
388 					to += strlen(to);
389 				}
390 			}
391 			break;
392 		default:
393 			*to++ = *fr;
394 			break;
395 		}
396 	}
397 	*to = '\0';
398 	return (e);
399 }
400 
401 #if TAB_COMPLETE_FILENAME
402 
403 /*
404  * Return a blank-separated list of filenames which "complete"
405  * the given string.
406  */
407 	public char *
408 fcomplete(s)
409 	char *s;
410 {
411 	char *fpat;
412 	char *qs;
413 
414 	if (secure)
415 		return (NULL);
416 	/*
417 	 * Complete the filename "s" by globbing "s*".
418 	 */
419 #if MSDOS_COMPILER && (MSDOS_COMPILER == MSOFTC || MSDOS_COMPILER == BORLANDC)
420 	/*
421 	 * But in DOS, we have to glob "s*.*".
422 	 * But if the final component of the filename already has
423 	 * a dot in it, just do "s*".
424 	 * (Thus, "FILE" is globbed as "FILE*.*",
425 	 *  but "FILE.A" is globbed as "FILE.A*").
426 	 */
427 	{
428 		char *slash;
429 		int len;
430 		for (slash = s+strlen(s)-1;  slash > s;  slash--)
431 			if (*slash == *PATHNAME_SEP || *slash == '/')
432 				break;
433 		len = strlen(s) + 4;
434 		fpat = (char *) ecalloc(len, sizeof(char));
435 		if (strchr(slash, '.') == NULL)
436 			SNPRINTF1(fpat, len, "%s*.*", s);
437 		else
438 			SNPRINTF1(fpat, len, "%s*", s);
439 	}
440 #else
441 	{
442 	int len = strlen(s) + 2;
443 	fpat = (char *) ecalloc(len, sizeof(char));
444 	SNPRINTF1(fpat, len, "%s*", s);
445 	}
446 #endif
447 	qs = lglob(fpat);
448 	s = shell_unquote(qs);
449 	if (strcmp(s,fpat) == 0)
450 	{
451 		/*
452 		 * The filename didn't expand.
453 		 */
454 		free(qs);
455 		qs = NULL;
456 	}
457 	free(s);
458 	free(fpat);
459 	return (qs);
460 }
461 #endif
462 
463 /*
464  * Try to determine if a file is "binary".
465  * This is just a guess, and we need not try too hard to make it accurate.
466  */
467 	public int
468 bin_file(f)
469 	int f;
470 {
471 	int i;
472 	int n;
473 	unsigned char data[64];
474 
475 	if (!seekable(f))
476 		return (0);
477 	if (lseek(f, (off_t)0, 0) == BAD_LSEEK)
478 		return (0);
479 	n = read(f, data, sizeof(data));
480 	for (i = 0;  i < n;  i++)
481 		if (binary_char(data[i]))
482 			return (1);
483 	return (0);
484 }
485 
486 /*
487  * Try to determine the size of a file by seeking to the end.
488  */
489 	static POSITION
490 seek_filesize(f)
491 	int f;
492 {
493 	off_t spos;
494 
495 	spos = lseek(f, (off_t)0, 2);
496 	if (spos == BAD_LSEEK)
497 		return (NULL_POSITION);
498 	return ((POSITION) spos);
499 }
500 
501 /*
502  * Read a string from a file.
503  * Return a pointer to the string in memory.
504  */
505 	static char *
506 readfd(fd)
507 	FILE *fd;
508 {
509 	int len;
510 	int ch;
511 	char *buf;
512 	char *p;
513 
514 	/*
515 	 * Make a guess about how many chars in the string
516 	 * and allocate a buffer to hold it.
517 	 */
518 	len = 100;
519 	buf = (char *) ecalloc(len, sizeof(char));
520 	for (p = buf;  ;  p++)
521 	{
522 		if ((ch = getc(fd)) == '\n' || ch == EOF)
523 			break;
524 		if (p - buf >= len-1)
525 		{
526 			/*
527 			 * The string is too big to fit in the buffer we have.
528 			 * Allocate a new buffer, twice as big.
529 			 */
530 			len *= 2;
531 			*p = '\0';
532 			p = (char *) ecalloc(len, sizeof(char));
533 			strcpy(p, buf);
534 			free(buf);
535 			buf = p;
536 			p = buf + strlen(buf);
537 		}
538 		*p = ch;
539 	}
540 	*p = '\0';
541 	return (buf);
542 }
543 
544 
545 
546 #if HAVE_POPEN
547 
548 FILE *popen();
549 
550 /*
551  * Execute a shell command.
552  * Return a pointer to a pipe connected to the shell command's standard output.
553  */
554 	static FILE *
555 shellcmd(cmd)
556 	char *cmd;
557 {
558 	FILE *fd;
559 
560 #if HAVE_SHELL
561 	char *shell;
562 
563 	shell = lgetenv("SHELL");
564 	if (shell != NULL && *shell != '\0')
565 	{
566 		char *scmd;
567 		char *esccmd;
568 
569 		/*
570 		 * Read the output of <$SHELL -c cmd>.
571 		 * Escape any metacharacters in the command.
572 		 */
573 		esccmd = shell_quote(cmd);
574 		if (esccmd == NULL)
575 		{
576 			fd = popen(cmd, "r");
577 		} else
578 		{
579 			int len = strlen(shell) + strlen(esccmd) + 5;
580 			scmd = (char *) ecalloc(len, sizeof(char));
581 			SNPRINTF3(scmd, len, "%s %s %s", shell, shell_coption(), esccmd);
582 			free(esccmd);
583 			fd = popen(scmd, "r");
584 			free(scmd);
585 		}
586 	} else
587 #endif
588 	{
589 		fd = popen(cmd, "r");
590 	}
591 	/*
592 	 * Redirection in `popen' might have messed with the
593 	 * standard devices.  Restore binary input mode.
594 	 */
595 	SET_BINARY(0);
596 	return (fd);
597 }
598 
599 #endif /* HAVE_POPEN */
600 
601 
602 /*
603  * Expand a filename, doing any system-specific metacharacter substitutions.
604  */
605 	public char *
606 lglob(filename)
607 	char *filename;
608 {
609 	char *gfilename;
610 	char *ofilename;
611 
612 	ofilename = fexpand(filename);
613 	if (secure)
614 		return (ofilename);
615 	filename = shell_unquote(ofilename);
616 
617 #ifdef DECL_GLOB_LIST
618 {
619 	/*
620 	 * The globbing function returns a list of names.
621 	 */
622 	int length;
623 	char *p;
624 	char *qfilename;
625 	DECL_GLOB_LIST(list)
626 
627 	GLOB_LIST(filename, list);
628 	if (GLOB_LIST_FAILED(list))
629 	{
630 		free(filename);
631 		return (ofilename);
632 	}
633 	length = 1; /* Room for trailing null byte */
634 	for (SCAN_GLOB_LIST(list, p))
635 	{
636 		INIT_GLOB_LIST(list, p);
637 		qfilename = shell_quote(p);
638 		if (qfilename != NULL)
639 		{
640 	  		length += strlen(qfilename) + 1;
641 			free(qfilename);
642 		}
643 	}
644 	gfilename = (char *) ecalloc(length, sizeof(char));
645 	for (SCAN_GLOB_LIST(list, p))
646 	{
647 		INIT_GLOB_LIST(list, p);
648 		qfilename = shell_quote(p);
649 		if (qfilename != NULL)
650 		{
651 			sprintf(gfilename + strlen(gfilename), "%s ", qfilename);
652 			free(qfilename);
653 		}
654 	}
655 	/*
656 	 * Overwrite the final trailing space with a null terminator.
657 	 */
658 	*--p = '\0';
659 	GLOB_LIST_DONE(list);
660 }
661 #else
662 #ifdef DECL_GLOB_NAME
663 {
664 	/*
665 	 * The globbing function returns a single name, and
666 	 * is called multiple times to walk thru all names.
667 	 */
668 	register char *p;
669 	register int len;
670 	register int n;
671 	char *pathname;
672 	char *qpathname;
673 	DECL_GLOB_NAME(fnd,drive,dir,fname,ext,handle)
674 
675 	GLOB_FIRST_NAME(filename, &fnd, handle);
676 	if (GLOB_FIRST_FAILED(handle))
677 	{
678 		free(filename);
679 		return (ofilename);
680 	}
681 
682 	_splitpath(filename, drive, dir, fname, ext);
683 	len = 100;
684 	gfilename = (char *) ecalloc(len, sizeof(char));
685 	p = gfilename;
686 	do {
687 		n = strlen(drive) + strlen(dir) + strlen(fnd.GLOB_NAME) + 1;
688 		pathname = (char *) ecalloc(n, sizeof(char));
689 		SNPRINTF3(pathname, n, "%s%s%s", drive, dir, fnd.GLOB_NAME);
690 		qpathname = shell_quote(pathname);
691 		free(pathname);
692 		if (qpathname != NULL)
693 		{
694 			n = strlen(qpathname);
695 			while (p - gfilename + n + 2 >= len)
696 			{
697 				/*
698 				 * No room in current buffer.
699 				 * Allocate a bigger one.
700 				 */
701 				len *= 2;
702 				*p = '\0';
703 				p = (char *) ecalloc(len, sizeof(char));
704 				strcpy(p, gfilename);
705 				free(gfilename);
706 				gfilename = p;
707 				p = gfilename + strlen(gfilename);
708 			}
709 			strcpy(p, qpathname);
710 			free(qpathname);
711 			p += n;
712 			*p++ = ' ';
713 		}
714 	} while (GLOB_NEXT_NAME(handle, &fnd) == 0);
715 
716 	/*
717 	 * Overwrite the final trailing space with a null terminator.
718 	 */
719 	*--p = '\0';
720 	GLOB_NAME_DONE(handle);
721 }
722 #else
723 #if HAVE_POPEN
724 {
725 	/*
726 	 * We get the shell to glob the filename for us by passing
727 	 * an "echo" command to the shell and reading its output.
728 	 */
729 	FILE *fd;
730 	char *s;
731 	char *lessecho;
732 	char *cmd;
733 	char *esc;
734 	int len;
735 
736 	esc = get_meta_escape();
737 	if (strlen(esc) == 0)
738 		esc = "-";
739 	esc = shell_quote(esc);
740 	if (esc == NULL)
741 	{
742 		free(filename);
743 		return (ofilename);
744 	}
745 	lessecho = lgetenv("LESSECHO");
746 	if (lessecho == NULL || *lessecho == '\0')
747 		lessecho = "lessecho";
748 	/*
749 	 * Invoke lessecho, and read its output (a globbed list of filenames).
750 	 */
751 	len = strlen(lessecho) + strlen(ofilename) + (7*strlen(metachars())) + 24;
752 	cmd = (char *) ecalloc(len, sizeof(char));
753 	SNPRINTF4(cmd, len, "%s -p0x%x -d0x%x -e%s ", lessecho, openquote, closequote, esc);
754 	free(esc);
755 	for (s = metachars();  *s != '\0';  s++)
756 		sprintf(cmd + strlen(cmd), "-n0x%x ", *s);
757 	sprintf(cmd + strlen(cmd), "-- %s", ofilename);
758 	fd = shellcmd(cmd);
759 	free(cmd);
760 	if (fd == NULL)
761 	{
762 		/*
763 		 * Cannot create the pipe.
764 		 * Just return the original (fexpanded) filename.
765 		 */
766 		free(filename);
767 		return (ofilename);
768 	}
769 	gfilename = readfd(fd);
770 	pclose(fd);
771 	if (*gfilename == '\0')
772 	{
773 		free(gfilename);
774 		free(filename);
775 		return (ofilename);
776 	}
777 }
778 #else
779 	/*
780 	 * No globbing functions at all.  Just use the fexpanded filename.
781 	 */
782 	gfilename = save(filename);
783 #endif
784 #endif
785 #endif
786 	free(filename);
787 	free(ofilename);
788 	return (gfilename);
789 }
790 
791 /*
792  * See if we should open a "replacement file"
793  * instead of the file we're about to open.
794  */
795 	public char *
796 open_altfile(filename, pf, pfd)
797 	char *filename;
798 	int *pf;
799 	void **pfd;
800 {
801 #if !HAVE_POPEN
802 	return (NULL);
803 #else
804 	char *lessopen;
805 	char *cmd;
806 	int len;
807 	FILE *fd;
808 #if HAVE_FILENO
809 	int returnfd = 0;
810 #endif
811 
812 	if (!use_lessopen || secure)
813 		return (NULL);
814 	ch_ungetchar(-1);
815 	if ((lessopen = lgetenv("LESSOPEN")) == NULL)
816 		return (NULL);
817 	if (strcmp(filename, "-") == 0)
818 		return (NULL);
819 	if (*lessopen == '|')
820 	{
821 		/*
822 		 * If LESSOPEN starts with a |, it indicates
823 		 * a "pipe preprocessor".
824 		 */
825 #if HAVE_FILENO
826 		lessopen++;
827 		returnfd = 1;
828 #else
829 		error("LESSOPEN pipe is not supported", NULL_PARG);
830 		return (NULL);
831 #endif
832 	}
833 
834 	len = strlen(lessopen) + strlen(filename) + 2;
835 	cmd = (char *) ecalloc(len, sizeof(char));
836 	SNPRINTF1(cmd, len, lessopen, filename);
837 	fd = shellcmd(cmd);
838 	free(cmd);
839 	if (fd == NULL)
840 	{
841 		/*
842 		 * Cannot create the pipe.
843 		 */
844 		return (NULL);
845 	}
846 #if HAVE_FILENO
847 	if (returnfd)
848 	{
849 		int f;
850 		char c;
851 
852 		/*
853 		 * Read one char to see if the pipe will produce any data.
854 		 * If it does, push the char back on the pipe.
855 		 */
856 		f = fileno(fd);
857 		SET_BINARY(f);
858 		if (read(f, &c, 1) != 1)
859 		{
860 			/*
861 			 * Pipe is empty.  This means there is no alt file.
862 			 */
863 			pclose(fd);
864 			return (NULL);
865 		}
866 		ch_ungetchar(c);
867 		*pfd = (void *) fd;
868 		*pf = f;
869 		return (save("-"));
870 	}
871 #endif
872 	cmd = readfd(fd);
873 	pclose(fd);
874 	if (*cmd == '\0')
875 		/*
876 		 * Pipe is empty.  This means there is no alt file.
877 		 */
878 		return (NULL);
879 	return (cmd);
880 #endif /* HAVE_POPEN */
881 }
882 
883 /*
884  * Close a replacement file.
885  */
886 	public void
887 close_altfile(altfilename, filename, pipefd)
888 	char *altfilename;
889 	char *filename;
890 	void *pipefd;
891 {
892 #if HAVE_POPEN
893 	char *lessclose;
894 	FILE *fd;
895 	char *cmd;
896 	int len;
897 
898 	if (secure)
899 		return;
900 	if (pipefd != NULL)
901 	{
902 #if OS2
903 		/*
904 		 * The pclose function of OS/2 emx sometimes fails.
905 		 * Send SIGINT to the piped process before closing it.
906 		 */
907 		kill(((FILE*)pipefd)->_pid, SIGINT);
908 #endif
909 		pclose((FILE*) pipefd);
910 	}
911 	if ((lessclose = lgetenv("LESSCLOSE")) == NULL)
912 	     	return;
913 	len = strlen(lessclose) + strlen(filename) + strlen(altfilename) + 2;
914 	cmd = (char *) ecalloc(len, sizeof(char));
915 	SNPRINTF2(cmd, len, lessclose, filename, altfilename);
916 	fd = shellcmd(cmd);
917 	free(cmd);
918 	if (fd != NULL)
919 		pclose(fd);
920 #endif
921 }
922 
923 /*
924  * Is the specified file a directory?
925  */
926 	public int
927 is_dir(filename)
928 	char *filename;
929 {
930 	int isdir = 0;
931 
932 	filename = shell_unquote(filename);
933 #if HAVE_STAT
934 {
935 	int r;
936 	struct stat statbuf;
937 
938 	r = stat(filename, &statbuf);
939 	isdir = (r >= 0 && S_ISDIR(statbuf.st_mode));
940 }
941 #else
942 #ifdef _OSK
943 {
944 	register int f;
945 
946 	f = open(filename, S_IREAD | S_IFDIR);
947 	if (f >= 0)
948 		close(f);
949 	isdir = (f >= 0);
950 }
951 #endif
952 #endif
953 	free(filename);
954 	return (isdir);
955 }
956 
957 /*
958  * Returns NULL if the file can be opened and
959  * is an ordinary file, otherwise an error message
960  * (if it cannot be opened or is a directory, etc.)
961  */
962 	public char *
963 bad_file(filename)
964 	char *filename;
965 {
966 	register char *m = NULL;
967 
968 	filename = shell_unquote(filename);
969 	if (is_dir(filename))
970 	{
971 		static char is_a_dir[] = " is a directory";
972 
973 		m = (char *) ecalloc(strlen(filename) + sizeof(is_a_dir),
974 			sizeof(char));
975 		strcpy(m, filename);
976 		strcat(m, is_a_dir);
977 	} else
978 	{
979 #if HAVE_STAT
980 		int r;
981 		struct stat statbuf;
982 
983 		r = stat(filename, &statbuf);
984 		if (r < 0)
985 		{
986 			m = errno_message(filename);
987 		} else if (force_open)
988 		{
989 			m = NULL;
990 		} else if (!S_ISREG(statbuf.st_mode))
991 		{
992 			static char not_reg[] = " is not a regular file (use -f to see it)";
993 			m = (char *) ecalloc(strlen(filename) + sizeof(not_reg),
994 				sizeof(char));
995 			strcpy(m, filename);
996 			strcat(m, not_reg);
997 		}
998 #endif
999 	}
1000 	free(filename);
1001 	return (m);
1002 }
1003 
1004 /*
1005  * Return the size of a file, as cheaply as possible.
1006  * In Unix, we can stat the file.
1007  */
1008 	public POSITION
1009 filesize(f)
1010 	int f;
1011 {
1012 #if HAVE_STAT
1013 	struct stat statbuf;
1014 
1015 	if (fstat(f, &statbuf) >= 0)
1016 		return ((POSITION) statbuf.st_size);
1017 #else
1018 #ifdef _OSK
1019 	long size;
1020 
1021 	if ((size = (long) _gs_size(f)) >= 0)
1022 		return ((POSITION) size);
1023 #endif
1024 #endif
1025 	return (seek_filesize(f));
1026 }
1027 
1028 /*
1029  *
1030  */
1031 	public char *
1032 shell_coption()
1033 {
1034 	return ("-c");
1035 }
1036