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 __RCSID("$MirOS: src/usr.bin/less/filename.c,v 1.4 2010/12/27 17:08:38 tg Exp $");
41 
42 #if HAVE_STAT
43 #include <sys/stat.h>
44 #ifndef S_ISDIR
45 #define	S_ISDIR(m)	(((m) & S_IFMT) == S_IFDIR)
46 #endif
47 #ifndef S_ISREG
48 #define	S_ISREG(m)	(((m) & S_IFMT) == S_IFREG)
49 #endif
50 #endif
51 
52 
53 extern int force_open;
54 extern int secure;
55 extern int use_lessopen;
56 extern IFILE curr_ifile;
57 extern IFILE old_ifile;
58 #if SPACES_IN_FILENAMES
59 extern char openquote;
60 extern char closequote;
61 #endif
62 
63 /*
64  * Remove quotes around a filename.
65  */
66 	public char *
shell_unquote(str)67 shell_unquote(str)
68 	char *str;
69 {
70 	char *name;
71 	char *p;
72 
73 	name = p = (char *) ecalloc(strlen(str)+1, sizeof(char));
74 	if (*str == openquote)
75 	{
76 		str++;
77 		while (*str != '\0')
78 		{
79 			if (*str == closequote)
80 			{
81 				if (str[1] != closequote)
82 					break;
83 				str++;
84 			}
85 			*p++ = *str++;
86 		}
87 	} else
88 	{
89 		char *esc = get_meta_escape();
90 		int esclen = strlen(esc);
91 		while (*str != '\0')
92 		{
93 			if (esclen > 0 && strncmp(str, esc, esclen) == 0)
94 				str += esclen;
95 			*p++ = *str++;
96 		}
97 	}
98 	*p = '\0';
99 	return (name);
100 }
101 
102 /*
103  * Get the shell's escape character.
104  */
105 	public char *
get_meta_escape()106 get_meta_escape()
107 {
108 	char *s;
109 
110 	s = lgetenv("LESSMETAESCAPE");
111 	if (s == NULL)
112 		s = DEF_METAESCAPE;
113 	return (s);
114 }
115 
116 /*
117  * Get the characters which the shell considers to be "metacharacters".
118  */
119 	static char *
metachars()120 metachars()
121 {
122 	static char *mchars = NULL;
123 
124 	if (mchars == NULL)
125 	{
126 		mchars = lgetenv("LESSMETACHARS");
127 		if (mchars == NULL)
128 			mchars = DEF_METACHARS;
129 	}
130 	return (mchars);
131 }
132 
133 /*
134  * Is this a shell metacharacter?
135  */
136 	static int
metachar(c)137 metachar(c)
138 	char c;
139 {
140 	return (strchr(metachars(), c) != NULL);
141 }
142 
143 /*
144  * Insert a backslash before each metacharacter in a string.
145  */
146 	public char *
shell_quote(s)147 shell_quote(s)
148 	char *s;
149 {
150 	char *p;
151 	char *newstr;
152 	int len;
153 	char *esc = get_meta_escape();
154 	int esclen = strlen(esc);
155 	int use_quotes = 0;
156 	int have_quotes = 0;
157 
158 	/*
159 	 * Determine how big a string we need to allocate.
160 	 */
161 	len = 1; /* Trailing null byte */
162 	for (p = s;  *p != '\0';  p++)
163 	{
164 		len++;
165 		if (*p == openquote || *p == closequote)
166 			have_quotes = 1;
167 		if (metachar(*p))
168 		{
169 			if (esclen == 0)
170 			{
171 				/*
172 				 * We've got a metachar, but this shell
173 				 * doesn't support escape chars.  Use quotes.
174 				 */
175 				use_quotes = 1;
176 			} else
177 			{
178 				/*
179 				 * Allow space for the escape char.
180 				 */
181 				len += esclen;
182 			}
183 		}
184 	}
185 	if (use_quotes)
186 	{
187 		if (have_quotes)
188 			/*
189 			 * We can't quote a string that contains quotes.
190 			 */
191 			return (NULL);
192 		len = strlen(s) + 3;
193 	}
194 	/*
195 	 * Allocate and construct the new string.
196 	 */
197 	newstr = p = (char *) ecalloc(len, sizeof(char));
198 	if (use_quotes)
199 	{
200 		snprintf(newstr, len, "%c%s%c", openquote, s, closequote);
201 	} else
202 	{
203 		while (*s != '\0')
204 		{
205 			if (metachar(*s))
206 			{
207 				/*
208 				 * Add the escape char.
209 				 */
210 				strlcpy(p, esc, newstr + len - p);
211 				p += esclen;
212 			}
213 			*p++ = *s++;
214 		}
215 		*p = '\0';
216 	}
217 	return (newstr);
218 }
219 
220 /*
221  * Return a pathname that points to a specified file in a specified directory.
222  * Return NULL if the file does not exist in the directory.
223  */
224 	static char *
dirfile(dirname,filename)225 dirfile(dirname, filename)
226 	char *dirname;
227 	char *filename;
228 {
229 	char *pathname;
230 	char *qpathname;
231 	int f;
232 	size_t len;
233 
234 	if (dirname == NULL || *dirname == '\0')
235 		return (NULL);
236 	/*
237 	 * Construct the full pathname.
238 	 */
239 	len = strlen(dirname) + strlen(filename) + 2;
240 	pathname = (char *) calloc(len, sizeof(char));
241 	if (pathname == NULL)
242 		return (NULL);
243 	snprintf(pathname, len, "%s%s%s", dirname, PATHNAME_SEP, filename);
244 	/*
245 	 * Make sure the file exists.
246 	 */
247 	qpathname = shell_unquote(pathname);
248 	f = open(qpathname, OPEN_READ);
249 	if (f < 0)
250 	{
251 		free(pathname);
252 		pathname = NULL;
253 	} else
254 	{
255 		close(f);
256 	}
257 	free(qpathname);
258 	return (pathname);
259 }
260 
261 /*
262  * Return the full pathname of the given file in the "home directory".
263  */
264 	public char *
homefile(filename)265 homefile(filename)
266 	char *filename;
267 {
268 	register char *pathname;
269 
270 	/*
271 	 * Try $HOME/filename.
272 	 */
273 	pathname = dirfile(lgetenv("HOME"), filename);
274 	if (pathname != NULL)
275 		return (pathname);
276 #if OS2
277 	/*
278 	 * Try $INIT/filename.
279 	 */
280 	pathname = dirfile(lgetenv("INIT"), filename);
281 	if (pathname != NULL)
282 		return (pathname);
283 #endif
284 #if MSDOS_COMPILER || OS2
285 	/*
286 	 * Look for the file anywhere on search path.
287 	 */
288 	pathname = (char *) calloc(_MAX_PATH, sizeof(char));
289 #if MSDOS_COMPILER==DJGPPC
290 	{
291 		char *res = searchpath(filename);
292 		if (res == 0)
293 			*pathname = '\0';
294 		else
295 			strlcpy(pathname, res, _MAX_PATH);
296 	}
297 #else
298 	_searchenv(filename, "PATH", pathname);
299 #endif
300 	if (*pathname != '\0')
301 		return (pathname);
302 	free(pathname);
303 #endif
304 	return (NULL);
305 }
306 
307 #ifdef HELPFILE
308 /*
309  * Find out where the help file is.
310  */
311 	public char *
find_helpfile()312 find_helpfile()
313 {
314 	char *helpfile;
315 
316 	if ((helpfile = getenv("LESSHELP")) != NULL && *helpfile != '\0')
317 		return (save(helpfile));
318 #if MSDOS_COMPILER || OS2
319 	return (homefile(HELPFILE));
320 #else
321 	return (save(HELPFILE));
322 #endif
323 }
324 #endif
325 
326 /*
327  * Expand a string, substituting any "%" with the current filename,
328  * and any "#" with the previous filename.
329  * But a string of N "%"s is just replaced with N-1 "%"s.
330  * Likewise for a string of N "#"s.
331  * {{ This is a lot of work just to support % and #. }}
332  */
333 	public char *
fexpand(s)334 fexpand(s)
335 	char *s;
336 {
337 	register char *fr, *to;
338 	register int n;
339 	register char *e;
340 	IFILE ifile;
341 
342 #define	fchar_ifile(c) \
343 	((c) == '%' ? curr_ifile : \
344 	 (c) == '#' ? old_ifile : NULL_IFILE)
345 
346 	/*
347 	 * Make one pass to see how big a buffer we
348 	 * need to allocate for the expanded string.
349 	 */
350 	n = 0;
351 	for (fr = s;  *fr != '\0';  fr++)
352 	{
353 		switch (*fr)
354 		{
355 		case '%':
356 		case '#':
357 			if (fr > s && fr[-1] == *fr)
358 			{
359 				/*
360 				 * Second (or later) char in a string
361 				 * of identical chars.  Treat as normal.
362 				 */
363 				n++;
364 			} else if (fr[1] != *fr)
365 			{
366 				/*
367 				 * Single char (not repeated).  Treat specially.
368 				 */
369 				ifile = fchar_ifile(*fr);
370 				if (ifile == NULL_IFILE)
371 					n++;
372 				else
373 					n += strlen(get_filename(ifile));
374 			}
375 			/*
376 			 * Else it is the first char in a string of
377 			 * identical chars.  Just discard it.
378 			 */
379 			break;
380 		default:
381 			n++;
382 			break;
383 		}
384 	}
385 
386 	e = (char *) ecalloc(n+1, sizeof(char));
387 
388 	/*
389 	 * Now copy the string, expanding any "%" or "#".
390 	 */
391 	to = e;
392 	for (fr = s;  *fr != '\0';  fr++)
393 	{
394 		switch (*fr)
395 		{
396 		case '%':
397 		case '#':
398 			if (fr > s && fr[-1] == *fr)
399 			{
400 				*to++ = *fr;
401 			} else if (fr[1] != *fr)
402 			{
403 				ifile = fchar_ifile(*fr);
404 				if (ifile == NULL_IFILE)
405 					*to++ = *fr;
406 				else
407 				{
408 					strlcpy(to, get_filename(ifile),
409 					    e + n + 1 - to);
410 					to += strlen(to);
411 				}
412 			}
413 			break;
414 		default:
415 			*to++ = *fr;
416 			break;
417 		}
418 	}
419 	*to = '\0';
420 	return (e);
421 }
422 
423 #if TAB_COMPLETE_FILENAME
424 
425 /*
426  * Return a blank-separated list of filenames which "complete"
427  * the given string.
428  */
429 	public char *
fcomplete(s)430 fcomplete(s)
431 	char *s;
432 {
433 	char *fpat;
434 	char *qs;
435 	size_t len;
436 
437 	if (secure)
438 		return (NULL);
439 	/*
440 	 * Complete the filename "s" by globbing "s*".
441 	 */
442 #if MSDOS_COMPILER && (MSDOS_COMPILER == MSOFTC || MSDOS_COMPILER == BORLANDC)
443 	/*
444 	 * But in DOS, we have to glob "s*.*".
445 	 * But if the final component of the filename already has
446 	 * a dot in it, just do "s*".
447 	 * (Thus, "FILE" is globbed as "FILE*.*",
448 	 *  but "FILE.A" is globbed as "FILE.A*").
449 	 */
450 	{
451 		char *slash;
452 		for (slash = s+strlen(s)-1;  slash > s;  slash--)
453 			if (*slash == *PATHNAME_SEP || *slash == '/')
454 				break;
455 		len = strlen(s) + 4;
456 		fpat = (char *) ecalloc(len, sizeof(char));
457 		if (strchr(slash, '.') == NULL)
458 			snprintf(fpat, len, "%s*.*", s);
459 		else
460 			snprintf(fpat, len, "%s*", s);
461 	}
462 #else
463 	len = strlen(s) + 2;
464 	fpat = (char *) ecalloc(len, sizeof(char));
465 	snprintf(fpat, len, "%s*", s);
466 #endif
467 	qs = lglob(fpat);
468 	s = shell_unquote(qs);
469 	if (strcmp(s,fpat) == 0)
470 	{
471 		/*
472 		 * The filename didn't expand.
473 		 */
474 		free(qs);
475 		qs = NULL;
476 	}
477 	free(s);
478 	free(fpat);
479 	return (qs);
480 }
481 #endif
482 
483 /*
484  * Try to determine if a file is "binary".
485  * This is just a guess, and we need not try too hard to make it accurate.
486  */
487 	public int
bin_file(f)488 bin_file(f)
489 	int f;
490 {
491 	int i;
492 	int n;
493 	unsigned char data[64];
494 
495 	if (!seekable(f))
496 		return (0);
497 	if (lseek(f, (off_t)0, 0) == BAD_LSEEK)
498 		return (0);
499 	n = read(f, data, sizeof(data));
500 	for (i = 0;  i < n;  i++)
501 		if (binary_char(data[i]))
502 			return (1);
503 	return (0);
504 }
505 
506 /*
507  * Try to determine the size of a file by seeking to the end.
508  */
509 	static POSITION
seek_filesize(f)510 seek_filesize(f)
511 	int f;
512 {
513 	off_t spos;
514 
515 	spos = lseek(f, (off_t)0, 2);
516 	if (spos == BAD_LSEEK)
517 		return (NULL_POSITION);
518 	return ((POSITION) spos);
519 }
520 
521 /*
522  * Read a string from a file.
523  * Return a pointer to the string in memory.
524  */
525 	static char *
readfd(fd)526 readfd(fd)
527 	FILE *fd;
528 {
529 	int len;
530 	int ch;
531 	char *buf;
532 	char *p;
533 
534 	/*
535 	 * Make a guess about how many chars in the string
536 	 * and allocate a buffer to hold it.
537 	 */
538 	len = 100;
539 	buf = (char *) ecalloc(len, sizeof(char));
540 	for (p = buf;  ;  p++)
541 	{
542 		if ((ch = getc(fd)) == '\n' || ch == EOF)
543 			break;
544 		if (p - buf >= len-1)
545 		{
546 			/*
547 			 * The string is too big to fit in the buffer we have.
548 			 * Allocate a new buffer, twice as big.
549 			 */
550 			len *= 2;
551 			*p = '\0';
552 			p = (char *) ecalloc(len, sizeof(char));
553 			strlcpy(p, buf, len);
554 			free(buf);
555 			buf = p;
556 			p = buf + strlen(buf);
557 		}
558 		*p = ch;
559 	}
560 	*p = '\0';
561 	return (buf);
562 }
563 
564 
565 
566 #if HAVE_POPEN
567 
568 FILE *popen();
569 
570 /*
571  * Execute a shell command.
572  * Return a pointer to a pipe connected to the shell command's standard output.
573  */
574 	static FILE *
shellcmd(cmd)575 shellcmd(cmd)
576 	char *cmd;
577 {
578 	FILE *fd;
579 	size_t len;
580 
581 #if HAVE_SHELL
582 	char *shell;
583 
584 	shell = lgetenv("SHELL");
585 	if (shell != NULL && *shell != '\0')
586 	{
587 		char *scmd;
588 		char *esccmd;
589 
590 		/*
591 		 * Read the output of <$SHELL -c cmd>.
592 		 * Escape any metacharacters in the command.
593 		 */
594 		esccmd = shell_quote(cmd);
595 		if (esccmd == NULL)
596 		{
597 			fd = popen(cmd, "r");
598 		} else
599 		{
600 			len = strlen(shell) + strlen(esccmd) + 5;
601 			scmd = (char *) ecalloc(len, sizeof(char));
602 			snprintf(scmd, len, "%s %s %s", shell, shell_coption(),
603 			    esccmd);
604 			free(esccmd);
605 			fd = popen(scmd, "r");
606 			free(scmd);
607 		}
608 	} else
609 #endif
610 	{
611 		fd = popen(cmd, "r");
612 	}
613 	/*
614 	 * Redirection in `popen' might have messed with the
615 	 * standard devices.  Restore binary input mode.
616 	 */
617 	SET_BINARY(0);
618 	return (fd);
619 }
620 
621 #endif /* HAVE_POPEN */
622 
623 
624 /*
625  * Expand a filename, doing any system-specific metacharacter substitutions.
626  */
627 	public char *
lglob(filename)628 lglob(filename)
629 	char *filename;
630 {
631 	char *gfilename;
632 	char *ofilename;
633 
634 	ofilename = fexpand(filename);
635 	if (secure)
636 		return (ofilename);
637 	filename = shell_unquote(ofilename);
638 
639 #ifdef DECL_GLOB_LIST
640 {
641 	/*
642 	 * The globbing function returns a list of names.
643 	 */
644 	int length;
645 	char *p = NULL;
646 	char *qfilename;
647 	DECL_GLOB_LIST(list)
648 
649 	GLOB_LIST(filename, list);
650 	if (GLOB_LIST_FAILED(list))
651 	{
652 		free(filename);
653 		return (ofilename);
654 	}
655 	length = 1; /* Room for trailing null byte */
656 	for (SCAN_GLOB_LIST(list, p))
657 	{
658 		INIT_GLOB_LIST(list, p);
659 		qfilename = shell_quote(p);
660 		if (qfilename != NULL)
661 		{
662 	  		length += strlen(qfilename) + 1;
663 			free(qfilename);
664 		}
665 	}
666 	gfilename = (char *) ecalloc(length, sizeof(char));
667 	for (SCAN_GLOB_LIST(list, p))
668 	{
669 		INIT_GLOB_LIST(list, p);
670 		qfilename = shell_quote(p);
671 		if (qfilename != NULL)
672 		{
673 			snprintf(gfilename + strlen(gfilename),
674 			    length - strlen(gfilename), "%s ", qfilename);
675 			free(qfilename);
676 		}
677 	}
678 	/*
679 	 * Overwrite the final trailing space with a null terminator.
680 	 */
681 	if (gfilename[0] != '\0' && gfilename[strlen(gfilename) - 1] == ' ')
682 		gfilename[strlen(gfilename) - 1] = '\0';
683 	GLOB_LIST_DONE(list);
684 }
685 #else
686 #ifdef DECL_GLOB_NAME
687 {
688 	/*
689 	 * The globbing function returns a single name, and
690 	 * is called multiple times to walk thru all names.
691 	 */
692 	register char *p;
693 	register int len;
694 	register int n;
695 	char *pathname;
696 	char *qpathname;
697 	DECL_GLOB_NAME(fnd,drive,dir,fname,ext,handle)
698 
699 	GLOB_FIRST_NAME(filename, &fnd, handle);
700 	if (GLOB_FIRST_FAILED(handle))
701 	{
702 		free(filename);
703 		return (ofilename);
704 	}
705 
706 	_splitpath(filename, drive, dir, fname, ext);
707 	len = 100;
708 	gfilename = (char *) ecalloc(len, sizeof(char));
709 	p = gfilename;
710 	do {
711 		n = strlen(drive) + strlen(dir) + strlen(fnd.GLOB_NAME) + 1;
712 		pathname = (char *) ecalloc(n, sizeof(char));
713 		snprintf(pathname, n, "%s%s%s", drive, dir, fnd.GLOB_NAME);
714 		qpathname = shell_quote(pathname);
715 		free(pathname);
716 		if (qpathname != NULL)
717 		{
718 			n = strlen(qpathname);
719 			while (p - gfilename + n + 2 >= len)
720 			{
721 				/*
722 				 * No room in current buffer.
723 				 * Allocate a bigger one.
724 				 */
725 				len *= 2;
726 				*p = '\0';
727 				p = (char *) ecalloc(len, sizeof(char));
728 				strlcpy(p, gfilename, len);
729 				free(gfilename);
730 				gfilename = p;
731 				p = gfilename + strlen(gfilename);
732 			}
733 			strlcpy(p, qpathname, gfilename + len - p);
734 			free(qpathname);
735 			p += n;
736 			*p++ = ' ';
737 		}
738 	} while (GLOB_NEXT_NAME(handle, &fnd) == 0);
739 
740 	/*
741 	 * Overwrite the final trailing space with a null terminator.
742 	 */
743 	*--p = '\0';
744 	GLOB_NAME_DONE(handle);
745 }
746 #else
747 #if HAVE_POPEN
748 {
749 	/*
750 	 * We get the shell to glob the filename for us by passing
751 	 * an "echo" command to the shell and reading its output.
752 	 */
753 	FILE *fd;
754 	char *s;
755 	char *lessecho;
756 	char *cmd;
757 	char *esc;
758 	size_t len;
759 
760 	esc = get_meta_escape();
761 	if (strlen(esc) == 0)
762 		esc = "-";
763 	esc = shell_quote(esc);
764 	if (esc == NULL)
765 	{
766 		free(filename);
767 		return (ofilename);
768 	}
769 	lessecho = lgetenv("LESSECHO");
770 	if (lessecho == NULL || *lessecho == '\0')
771 		lessecho = "lessecho";
772 	/*
773 	 * Invoke lessecho, and read its output (a globbed list of filenames).
774 	 */
775 	len = strlen(lessecho) + strlen(ofilename) + (7*strlen(metachars())) + 24;
776 	cmd = (char *) ecalloc(len, sizeof(char));
777 	snprintf(cmd, len, "%s -p0x%x -d0x%x -e%s ", lessecho, openquote,
778 	    closequote, esc);
779 	free(esc);
780 	for (s = metachars();  *s != '\0';  s++)
781 		snprintf(cmd + strlen(cmd), len - strlen(cmd), "-n0x%x ", *s);
782 	snprintf(cmd + strlen(cmd), len - strlen(cmd), "-- %s", ofilename);
783 	fd = shellcmd(cmd);
784 	free(cmd);
785 	if (fd == NULL)
786 	{
787 		/*
788 		 * Cannot create the pipe.
789 		 * Just return the original (fexpanded) filename.
790 		 */
791 		free(filename);
792 		return (ofilename);
793 	}
794 	gfilename = readfd(fd);
795 	pclose(fd);
796 	if (*gfilename == '\0')
797 	{
798 		free(gfilename);
799 		free(filename);
800 		return (ofilename);
801 	}
802 }
803 #else
804 	/*
805 	 * No globbing functions at all.  Just use the fexpanded filename.
806 	 */
807 	gfilename = save(filename);
808 #endif
809 #endif
810 #endif
811 	free(filename);
812 	free(ofilename);
813 	return (gfilename);
814 }
815 
816 /*
817  * See if we should open a "replacement file"
818  * instead of the file we're about to open.
819  */
820 	public char *
open_altfile(filename,pf,pfd)821 open_altfile(filename, pf, pfd)
822 	char *filename;
823 	int *pf;
824 	void **pfd;
825 {
826 #if !HAVE_POPEN
827 	return (NULL);
828 #else
829 	char *lessopen;
830 	char *cmd, *cp;
831 	FILE *fd;
832 	size_t i, len;
833 	int found;
834 #if HAVE_FILENO
835 	int returnfd = 0;
836 #endif
837 
838 	if (!use_lessopen || secure)
839 		return (NULL);
840 	ch_ungetchar(-1);
841 	if ((lessopen = lgetenv("LESSOPEN")) == NULL)
842 		return (NULL);
843 	if (strcmp(filename, "-") == 0)
844 		return (NULL);
845 	if (*lessopen == '|')
846 	{
847 		/*
848 		 * If LESSOPEN starts with a |, it indicates
849 		 * a "pipe preprocessor".
850 		 */
851 #if HAVE_FILENO
852 		lessopen++;
853 		returnfd = 1;
854 #else
855 		error("LESSOPEN pipe is not supported", NULL_PARG);
856 		return (NULL);
857 #endif
858 	}
859 
860 	/* strlen(filename) is guaranteed to be > 0 */
861 	len = strlen(lessopen) + strlen(filename);
862 	cmd = (char *) ecalloc(len, sizeof(char));
863 	for (cp = cmd, i = 0, found = 0; i < strlen(lessopen); i++) {
864 		if (!found && lessopen[i] == '%' && lessopen[i + 1] == 's') {
865 			found = 1;
866 			strlcat(cmd, filename, len);
867 			cp += strlen(filename);
868 			i++;
869 		} else
870 			*cp++ = lessopen[i];
871 	}
872 	fd = shellcmd(cmd);
873 	free(cmd);
874 	if (fd == NULL)
875 	{
876 		/*
877 		 * Cannot create the pipe.
878 		 */
879 		return (NULL);
880 	}
881 #if HAVE_FILENO
882 	if (returnfd)
883 	{
884 		int f;
885 		char c;
886 
887 		/*
888 		 * Read one char to see if the pipe will produce any data.
889 		 * If it does, push the char back on the pipe.
890 		 */
891 		f = fileno(fd);
892 		SET_BINARY(f);
893 		if (read(f, &c, 1) != 1)
894 		{
895 			/*
896 			 * Pipe is empty.  This means there is no alt file.
897 			 */
898 			pclose(fd);
899 			return (NULL);
900 		}
901 		ch_ungetchar(c);
902 		*pfd = (void *) fd;
903 		*pf = f;
904 		return (save("-"));
905 	}
906 #endif
907 	cmd = readfd(fd);
908 	pclose(fd);
909 	if (*cmd == '\0')
910 		/*
911 		 * Pipe is empty.  This means there is no alt file.
912 		 */
913 		return (NULL);
914 	return (cmd);
915 #endif /* HAVE_POPEN */
916 }
917 
918 /*
919  * Close a replacement file.
920  */
921 	public void
close_altfile(altfilename,filename,pipefd)922 close_altfile(altfilename, filename, pipefd)
923 	char *altfilename;
924 	char *filename;
925 	void *pipefd;
926 {
927 #if HAVE_POPEN
928 	char *lessclose;
929 	FILE *fd;
930 	char *cmd, *cp;
931 	size_t i, len;
932 	int found;
933 
934 	if (secure)
935 		return;
936 	if (pipefd != NULL)
937 	{
938 #if OS2
939 		/*
940 		 * The pclose function of OS/2 emx sometimes fails.
941 		 * Send SIGINT to the piped process before closing it.
942 		 */
943 		kill(((FILE*)pipefd)->_pid, SIGINT);
944 #endif
945 		pclose((FILE*) pipefd);
946 	}
947 	if ((lessclose = lgetenv("LESSCLOSE")) == NULL)
948 	     	return;
949 	/* strlen(filename) is guaranteed to be > 0 */
950 	len = strlen(lessclose) + strlen(filename) + strlen(altfilename);
951 	cmd = (char *) ecalloc(len, sizeof(char));
952 	for (cp = cmd, i = 0, found = 0; i < strlen(lessclose); i++) {
953 		if (found < 2 && lessclose[i] == '%' && lessclose[i + 1] == 's') {
954 			if (++found == 1) {
955 				strlcat(cmd, filename, len);
956 				cp += strlen(filename);
957 			} else {
958 				strlcat(cmd, altfilename, len);
959 				cp += strlen(altfilename);
960 			}
961 			i++;
962 		} else
963 			*cp++ = lessclose[i];
964 	}
965 	fd = shellcmd(cmd);
966 	free(cmd);
967 	if (fd != NULL)
968 		pclose(fd);
969 #endif
970 }
971 
972 /*
973  * Is the specified file a directory?
974  */
975 	public int
is_dir(filename)976 is_dir(filename)
977 	char *filename;
978 {
979 	int isdir = 0;
980 
981 	filename = shell_unquote(filename);
982 #if HAVE_STAT
983 {
984 	int r;
985 	struct stat statbuf;
986 
987 	r = stat(filename, &statbuf);
988 	isdir = (r >= 0 && S_ISDIR(statbuf.st_mode));
989 }
990 #else
991 #ifdef _OSK
992 {
993 	register int f;
994 
995 	f = open(filename, S_IREAD | S_IFDIR);
996 	if (f >= 0)
997 		close(f);
998 	isdir = (f >= 0);
999 }
1000 #endif
1001 #endif
1002 	free(filename);
1003 	return (isdir);
1004 }
1005 
1006 /*
1007  * Returns NULL if the file can be opened and
1008  * is an ordinary file, otherwise an error message
1009  * (if it cannot be opened or is a directory, etc.)
1010  */
1011 	public char *
bad_file(filename)1012 bad_file(filename)
1013 	char *filename;
1014 {
1015 	register char *m = NULL;
1016 	size_t len;
1017 
1018 	filename = shell_unquote(filename);
1019 	if (is_dir(filename))
1020 	{
1021 		static char is_a_dir[] = " is a directory";
1022 
1023 		len = strlen(filename) + sizeof(is_a_dir);
1024 		m = (char *) ecalloc(len, sizeof(char));
1025 		strlcpy(m, filename, len);
1026 		strlcat(m, is_a_dir, len);
1027 	} else
1028 	{
1029 #if HAVE_STAT
1030 		int r;
1031 		struct stat statbuf;
1032 
1033 		r = stat(filename, &statbuf);
1034 		if (r < 0)
1035 		{
1036 			m = errno_message(filename);
1037 		} else if (force_open)
1038 		{
1039 			m = NULL;
1040 		} else if (!S_ISREG(statbuf.st_mode))
1041 		{
1042 			static char not_reg[] = " is not a regular file (use -f to see it)";
1043 			len = strlen(filename) + sizeof(not_reg);
1044 			m = (char *) ecalloc(len, sizeof(char));
1045 			strlcpy(m, filename, len);
1046 			strlcat(m, not_reg, len);
1047 		}
1048 #endif
1049 	}
1050 	free(filename);
1051 	return (m);
1052 }
1053 
1054 /*
1055  * Return the size of a file, as cheaply as possible.
1056  * In Unix, we can stat the file.
1057  */
1058 	public POSITION
filesize(f)1059 filesize(f)
1060 	int f;
1061 {
1062 #if HAVE_STAT
1063 	struct stat statbuf;
1064 
1065 	if (fstat(f, &statbuf) >= 0)
1066 		return ((POSITION) statbuf.st_size);
1067 #else
1068 #ifdef _OSK
1069 	long size;
1070 
1071 	if ((size = (long) _gs_size(f)) >= 0)
1072 		return ((POSITION) size);
1073 #endif
1074 #endif
1075 	return (seek_filesize(f));
1076 }
1077 
1078 /*
1079  *
1080  */
1081 	public char *
shell_coption()1082 shell_coption()
1083 {
1084 	return ("-c");
1085 }
1086