fts.c revision 1.9
1/*-
2 * Copyright (c) 1990, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. 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
34#if defined(LIBC_SCCS) && !defined(lint)
35/* from: static char sccsid[] = "@(#)fts.c	8.4 (Berkeley) 4/16/94"; */
36static char *rcsid = "$Id: fts.c,v 1.9 1994/04/17 02:21:02 cgd Exp $";
37#endif /* LIBC_SCCS and not lint */
38
39#include <sys/param.h>
40#include <sys/stat.h>
41
42#include <dirent.h>
43#include <errno.h>
44#include <fcntl.h>
45#include <fts.h>
46#include <stdlib.h>
47#include <string.h>
48#include <unistd.h>
49
50static FTSENT	*fts_alloc __P((FTS *, char *, int));
51static FTSENT	*fts_build __P((FTS *, int));
52static void	 fts_lfree __P((FTSENT *));
53static void	 fts_load __P((FTS *, FTSENT *));
54static size_t	 fts_maxarglen __P((char * const *));
55static void	 fts_padjust __P((FTS *, void *));
56static int	 fts_palloc __P((FTS *, size_t));
57static FTSENT	*fts_sort __P((FTS *, FTSENT *, int));
58static u_short	 fts_stat __P((FTS *, FTSENT *, int));
59
60#define	ISDOT(a)	(a[0] == '.' && (!a[1] || a[1] == '.' && !a[2]))
61
62#define	ISSET(opt)	(sp->fts_options & opt)
63#define	SET(opt)	(sp->fts_options |= opt)
64
65#define	CHDIR(sp, path)	(!ISSET(FTS_NOCHDIR) && chdir(path))
66#define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
67
68/* fts_build flags */
69#define	BCHILD		1		/* fts_children */
70#define	BNAMES		2		/* fts_children, names only */
71#define	BREAD		3		/* fts_read */
72
73FTS *
74fts_open(argv, options, compar)
75	char * const *argv;
76	register int options;
77	int (*compar)();
78{
79	register FTS *sp;
80	register FTSENT *p, *root;
81	register int nitems;
82	FTSENT *parent, *tmp;
83	int len;
84
85	/* Options check. */
86	if (options & ~FTS_OPTIONMASK) {
87		errno = EINVAL;
88		return (NULL);
89	}
90
91	/* Allocate/initialize the stream */
92	if ((sp = malloc((u_int)sizeof(FTS))) == NULL)
93		return (NULL);
94	memset(sp, 0, sizeof(FTS));
95	sp->fts_compar = compar;
96	sp->fts_options = options;
97
98	/* Logical walks turn on NOCHDIR; symbolic links are too hard. */
99	if (ISSET(FTS_LOGICAL))
100		SET(FTS_NOCHDIR);
101
102	/*
103	 * Start out with 1K of path space, and enough, in any case,
104	 * to hold the user's paths.
105	 */
106	if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
107		goto mem1;
108
109	/* Allocate/initialize root's parent. */
110	if ((parent = fts_alloc(sp, "", 0)) == NULL)
111		goto mem2;
112	parent->fts_level = FTS_ROOTPARENTLEVEL;
113
114	/* Allocate/initialize root(s). */
115	for (root = NULL, nitems = 0; *argv; ++argv, ++nitems) {
116		/* Don't allow zero-length paths. */
117		if ((len = strlen(*argv)) == 0) {
118			errno = ENOENT;
119			goto mem3;
120		}
121
122		p = fts_alloc(sp, *argv, len);
123		p->fts_level = FTS_ROOTLEVEL;
124		p->fts_parent = parent;
125		p->fts_accpath = p->fts_name;
126		p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW));
127
128		/* Command-line "." and ".." are real directories. */
129		if (p->fts_info == FTS_DOT)
130			p->fts_info = FTS_D;
131
132		/*
133		 * If comparison routine supplied, traverse in sorted
134		 * order; otherwise traverse in the order specified.
135		 */
136		if (compar) {
137			p->fts_link = root;
138			root = p;
139		} else {
140			p->fts_link = NULL;
141			if (root == NULL)
142				tmp = root = p;
143			else {
144				tmp->fts_link = p;
145				tmp = p;
146			}
147		}
148	}
149	if (compar && nitems > 1)
150		root = fts_sort(sp, root, nitems);
151
152	/*
153	 * Allocate a dummy pointer and make fts_read think that we've just
154	 * finished the node before the root(s); set p->fts_info to FTS_INIT
155	 * so that everything about the "current" node is ignored.
156	 */
157	if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
158		goto mem3;
159	sp->fts_cur->fts_link = root;
160	sp->fts_cur->fts_info = FTS_INIT;
161
162	/*
163	 * If using chdir(2), grab a file descriptor pointing to dot to insure
164	 * that we can get back here; this could be avoided for some paths,
165	 * but almost certainly not worth the effort.  Slashes, symbolic links,
166	 * and ".." are all fairly nasty problems.  Note, if we can't get the
167	 * descriptor we run anyway, just more slowly.
168	 */
169	if (!ISSET(FTS_NOCHDIR) && (sp->fts_rfd = open(".", O_RDONLY, 0)) < 0)
170		SET(FTS_NOCHDIR);
171
172	return (sp);
173
174mem3:	fts_lfree(root);
175	free(parent);
176mem2:	free(sp->fts_path);
177mem1:	free(sp);
178	return (NULL);
179}
180
181static void
182fts_load(sp, p)
183	FTS *sp;
184	register FTSENT *p;
185{
186	register int len;
187	register char *cp;
188
189	/*
190	 * Load the stream structure for the next traversal.  Since we don't
191	 * actually enter the directory until after the preorder visit, set
192	 * the fts_accpath field specially so the chdir gets done to the right
193	 * place and the user can access the first node.  From fts_open it's
194	 * known that the path will fit.
195	 */
196	len = p->fts_pathlen = p->fts_namelen;
197	memmove(sp->fts_path, p->fts_name, len + 1);
198	if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
199		len = strlen(++cp);
200		memmove(p->fts_name, cp, len + 1);
201		p->fts_namelen = len;
202	}
203	p->fts_accpath = p->fts_path = sp->fts_path;
204	sp->fts_dev = p->fts_dev;
205}
206
207int
208fts_close(sp)
209	FTS *sp;
210{
211	register FTSENT *freep, *p;
212	int saved_errno;
213
214	/*
215	 * This still works if we haven't read anything -- the dummy structure
216	 * points to the root list, so we step through to the end of the root
217	 * list which has a valid parent pointer.
218	 */
219	if (sp->fts_cur) {
220		for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
221			freep = p;
222			p = p->fts_link ? p->fts_link : p->fts_parent;
223			free(freep);
224		}
225		free(p);
226	}
227
228	/* Free up child linked list, sort array, path buffer. */
229	if (sp->fts_child)
230		fts_lfree(sp->fts_child);
231	if (sp->fts_array)
232		free(sp->fts_array);
233	free(sp->fts_path);
234
235	/* Return to original directory, save errno if necessary. */
236	if (!ISSET(FTS_NOCHDIR)) {
237		saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
238		(void)close(sp->fts_rfd);
239	}
240
241	/* Free up the stream pointer. */
242	free(sp);
243
244	/* Set errno and return. */
245	if (!ISSET(FTS_NOCHDIR) && saved_errno) {
246		errno = saved_errno;
247		return (-1);
248	}
249	return (0);
250}
251
252/*
253 * Special case a root of "/" so that slashes aren't appended which would
254 * cause paths to be written as "//foo".
255 */
256#define	NAPPEND(p)							\
257	(p->fts_level == FTS_ROOTLEVEL && p->fts_pathlen == 1 &&	\
258	    p->fts_path[0] == '/' ? 0 : p->fts_pathlen)
259
260FTSENT *
261fts_read(sp)
262	register FTS *sp;
263{
264	register FTSENT *p, *tmp;
265	register int instr;
266	register char *t;
267	int saved_errno;
268
269	/* If finished or unrecoverable error, return NULL. */
270	if (sp->fts_cur == NULL || ISSET(FTS_STOP))
271		return (NULL);
272
273	/* Set current node pointer. */
274	p = sp->fts_cur;
275
276	/* Save and zero out user instructions. */
277	instr = p->fts_instr;
278	p->fts_instr = FTS_NOINSTR;
279
280	/* Any type of file may be re-visited; re-stat and re-turn. */
281	if (instr == FTS_AGAIN) {
282		p->fts_info = fts_stat(sp, p, 0);
283		return (p);
284	}
285
286	/*
287	 * Following a symlink -- SLNONE test allows application to see
288	 * SLNONE and recover.  If indirecting through a symlink, have
289	 * keep a pointer to current location.  If unable to get that
290	 * pointer, follow fails.
291	 */
292	if (instr == FTS_FOLLOW &&
293	    (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
294		p->fts_info = fts_stat(sp, p, 1);
295		if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR))
296			if ((p->fts_symfd = open(".", O_RDONLY, 0)) < 0) {
297				p->fts_errno = errno;
298				p->fts_info = FTS_ERR;
299			} else
300				p->fts_flags |= FTS_SYMFOLLOW;
301		return (p);
302	}
303
304	/* Directory in pre-order. */
305	if (p->fts_info == FTS_D) {
306		/* If skipped or crossed mount point, do post-order visit. */
307		if (instr == FTS_SKIP ||
308		    ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev) {
309			if (p->fts_flags & FTS_SYMFOLLOW)
310				(void)close(p->fts_symfd);
311			if (sp->fts_child) {
312				fts_lfree(sp->fts_child);
313				sp->fts_child = NULL;
314			}
315			p->fts_info = FTS_DP;
316			return (p);
317		}
318
319		/* Rebuild if only read the names and now traversing. */
320		if (sp->fts_child && sp->fts_options & FTS_NAMEONLY) {
321			sp->fts_options &= ~FTS_NAMEONLY;
322			fts_lfree(sp->fts_child);
323			sp->fts_child = NULL;
324		}
325
326		/*
327		 * Cd to the subdirectory.
328		 *
329		 * If have already read and now fail to chdir, whack the list
330		 * to make the names come out right, and set the parent errno
331		 * so the application will eventually get an error condition.
332		 * Set the FTS_DONTCHDIR flag so that when we logically change
333		 * directories back to the parent we don't do a chdir.
334		 *
335		 * If haven't read do so.  If the read fails, fts_build sets
336		 * FTS_STOP or the fts_info field of the node.
337		 */
338		if (sp->fts_child) {
339			if (CHDIR(sp, p->fts_accpath)) {
340				p->fts_errno = errno;
341				p->fts_flags |= FTS_DONTCHDIR;
342				for (p = sp->fts_child; p; p = p->fts_link)
343					p->fts_accpath =
344					    p->fts_parent->fts_accpath;
345			}
346		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
347			if (ISSET(FTS_STOP))
348				return (NULL);
349			return (p);
350		}
351		p = sp->fts_child;
352		sp->fts_child = NULL;
353		goto name;
354	}
355
356	/* Move to the next node on this level. */
357next:	tmp = p;
358	if (p = p->fts_link) {
359		free(tmp);
360
361		/*
362		 * If reached the top, return to the original directory, and
363		 * load the paths for the next root.
364		 */
365		if (p->fts_level == FTS_ROOTLEVEL) {
366			if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
367				SET(FTS_STOP);
368				return (NULL);
369			}
370			fts_load(sp, p);
371			return (sp->fts_cur = p);
372		}
373
374		/*
375		 * User may have called fts_set on the node.  If skipped,
376		 * ignore.  If followed, get a file descriptor so we can
377		 * get back if necessary.
378		 */
379		if (p->fts_instr == FTS_SKIP)
380			goto next;
381		if (p->fts_instr == FTS_FOLLOW) {
382			p->fts_info = fts_stat(sp, p, 1);
383			if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR))
384				if ((p->fts_symfd =
385				    open(".", O_RDONLY, 0)) < 0) {
386					p->fts_errno = errno;
387					p->fts_info = FTS_ERR;
388				} else
389					p->fts_flags |= FTS_SYMFOLLOW;
390			p->fts_instr = FTS_NOINSTR;
391		}
392
393name:		t = sp->fts_path + NAPPEND(p->fts_parent);
394		*t++ = '/';
395		memmove(t, p->fts_name, p->fts_namelen + 1);
396		return (sp->fts_cur = p);
397	}
398
399	/* Move up to the parent node. */
400	p = tmp->fts_parent;
401	free(tmp);
402
403	if (p->fts_level == FTS_ROOTPARENTLEVEL) {
404		/*
405		 * Done; free everything up and set errno to 0 so the user
406		 * can distinguish between error and EOF.
407		 */
408		free(p);
409		errno = 0;
410		return (sp->fts_cur = NULL);
411	}
412
413	/* Nul terminate the pathname. */
414	sp->fts_path[p->fts_pathlen] = '\0';
415
416	/*
417	 * Return to the parent directory.  If at a root node or came through
418	 * a symlink, go back through the file descriptor.  Otherwise, cd up
419	 * one directory.
420	 */
421	if (p->fts_level == FTS_ROOTLEVEL) {
422		if (!ISSET(FTS_NOCHDIR) && FCHDIR(sp, sp->fts_rfd)) {
423			SET(FTS_STOP);
424			return (NULL);
425		}
426	} else if (p->fts_flags & FTS_SYMFOLLOW) {
427		if (FCHDIR(sp, p->fts_symfd)) {
428			saved_errno = errno;
429			(void)close(p->fts_symfd);
430			errno = saved_errno;
431			SET(FTS_STOP);
432			return (NULL);
433		}
434		(void)close(p->fts_symfd);
435	} else if (!(p->fts_flags & FTS_DONTCHDIR)) {
436		if (CHDIR(sp, "..")) {
437			SET(FTS_STOP);
438			return (NULL);
439		}
440	}
441	p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
442	return (sp->fts_cur = p);
443}
444
445/*
446 * Fts_set takes the stream as an argument although it's not used in this
447 * implementation; it would be necessary if anyone wanted to add global
448 * semantics to fts using fts_set.  An error return is allowed for similar
449 * reasons.
450 */
451/* ARGSUSED */
452int
453fts_set(sp, p, instr)
454	FTS *sp;
455	FTSENT *p;
456	int instr;
457{
458	if (instr && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
459	    instr != FTS_NOINSTR && instr != FTS_SKIP) {
460		errno = EINVAL;
461		return (1);
462	}
463	p->fts_instr = instr;
464	return (0);
465}
466
467FTSENT *
468fts_children(sp, instr)
469	register FTS *sp;
470	int instr;
471{
472	register FTSENT *p;
473	int fd;
474
475	if (instr && instr != FTS_NAMEONLY) {
476		errno = EINVAL;
477		return (NULL);
478	}
479
480	/* Set current node pointer. */
481	p = sp->fts_cur;
482
483	/*
484	 * Errno set to 0 so user can distinguish empty directory from
485	 * an error.
486	 */
487	errno = 0;
488
489	/* Fatal errors stop here. */
490	if (ISSET(FTS_STOP))
491		return (NULL);
492
493	/* Return logical hierarchy of user's arguments. */
494	if (p->fts_info == FTS_INIT)
495		return (p->fts_link);
496
497	/*
498	 * If not a directory being visited in pre-order, stop here.  Could
499	 * allow FTS_DNR, assuming the user has fixed the problem, but the
500	 * same effect is available with FTS_AGAIN.
501	 */
502	if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
503		return (NULL);
504
505	/* Free up any previous child list. */
506	if (sp->fts_child)
507		fts_lfree(sp->fts_child);
508
509	if (instr == FTS_NAMEONLY) {
510		sp->fts_options |= FTS_NAMEONLY;
511		instr = BNAMES;
512	} else
513		instr = BCHILD;
514
515	/*
516	 * If using chdir on a relative path and called BEFORE fts_read does
517	 * its chdir to the root of a traversal, we can lose -- we need to
518	 * chdir into the subdirectory, and we don't know where the current
519	 * directory is, so we can't get back so that the upcoming chdir by
520	 * fts_read will work.
521	 */
522	if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
523	    ISSET(FTS_NOCHDIR))
524		return (sp->fts_child = fts_build(sp, instr));
525
526	if ((fd = open(".", O_RDONLY, 0)) < 0)
527		return (NULL);
528	sp->fts_child = fts_build(sp, instr);
529	if (fchdir(fd))
530		return (NULL);
531	(void)close(fd);
532	return (sp->fts_child);
533}
534
535/*
536 * This is the tricky part -- do not casually change *anything* in here.  The
537 * idea is to build the linked list of entries that are used by fts_children
538 * and fts_read.  There are lots of special cases.
539 *
540 * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
541 * set and it's a physical walk (so that symbolic links can't be directories),
542 * we can do things quickly.  First, if it's a 4.4BSD file system, the type
543 * of the file is in the directory entry.  Otherwise, we assume that the number
544 * of subdirectories in a node is equal to the number of links to the parent.
545 * The former skips all stat calls.  The latter skips stat calls in any leaf
546 * directories and for any files after the subdirectories in the directory have
547 * been found, cutting the stat calls by about 2/3.
548 */
549static FTSENT *
550fts_build(sp, type)
551	register FTS *sp;
552	int type;
553{
554	register struct dirent *dp;
555	register FTSENT *p, *head;
556	register int nitems;
557	FTSENT *cur, *tail;
558	DIR *dirp;
559	void *adjaddr;
560	int cderrno, descend, len, level, maxlen, nlinks, saved_errno;
561	char *cp;
562
563	/* Set current node pointer. */
564	cur = sp->fts_cur;
565
566	/*
567	 * Open the directory for reading.  If this fails, we're done.
568	 * If being called from fts_read, set the fts_info field.
569	 */
570	if ((dirp = opendir(cur->fts_accpath)) == NULL) {
571		if (type == BREAD) {
572			cur->fts_info = FTS_DNR;
573			cur->fts_errno = errno;
574		}
575		return (NULL);
576	}
577
578	/*
579	 * Nlinks is the number of possible entries of type directory in the
580	 * directory if we're cheating on stat calls, 0 if we're not doing
581	 * any stat calls at all, -1 if we're doing stats on everything.
582	 */
583	if (type == BNAMES)
584		nlinks = 0;
585	else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL))
586		nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
587	else
588		nlinks = -1;
589
590#ifdef notdef
591	(void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
592	(void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
593	    ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
594#endif
595	/*
596	 * If we're going to need to stat anything or we want to descend
597	 * and stay in the directory, chdir.  If this fails we keep going,
598	 * but set a flag so we don't chdir after the post-order visit.
599	 * We won't be able to stat anything, but we can still return the
600	 * names themselves.  Note, that since fts_read won't be able to
601	 * chdir into the directory, it will have to return different path
602	 * names than before, i.e. "a/b" instead of "b".  Since the node
603	 * has already been visited in pre-order, have to wait until the
604	 * post-order visit to return the error.  There is a special case
605	 * here, if there was nothing to stat then it's not an error to
606	 * not be able to stat.  This is all fairly nasty.  If a program
607	 * needed sorted entries or stat information, they had better be
608	 * checking FTS_NS on the returned nodes.
609	 */
610	cderrno = 0;
611	if (nlinks || type == BREAD)
612		if (FCHDIR(sp, dirfd(dirp))) {
613			if (nlinks && type == BREAD)
614				cur->fts_errno = errno;
615			cur->fts_flags |= FTS_DONTCHDIR;
616			descend = 0;
617			cderrno = errno;
618		} else
619			descend = 1;
620	else
621		descend = 0;
622
623	/*
624	 * Figure out the max file name length that can be stored in the
625	 * current path -- the inner loop allocates more path as necessary.
626	 * We really wouldn't have to do the maxlen calculations here, we
627	 * could do them in fts_read before returning the path, but it's a
628	 * lot easier here since the length is part of the dirent structure.
629	 *
630	 * If not changing directories set a pointer so that can just append
631	 * each new name into the path.
632	 */
633	maxlen = sp->fts_pathlen - cur->fts_pathlen - 1;
634	len = NAPPEND(cur);
635	if (ISSET(FTS_NOCHDIR)) {
636		cp = sp->fts_path + len;
637		*cp++ = '/';
638	}
639
640	level = cur->fts_level + 1;
641
642	/* Read the directory, attaching each entry to the `link' pointer. */
643	adjaddr = NULL;
644	for (head = tail = NULL, nitems = 0; dp = readdir(dirp);) {
645		if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
646			continue;
647
648		if ((p = fts_alloc(sp, dp->d_name, (int)dp->d_namlen)) == NULL)
649			goto mem1;
650		if (dp->d_namlen > maxlen) {
651			if (fts_palloc(sp, (size_t)dp->d_namlen)) {
652				/*
653				 * No more memory for path or structures.  Save
654				 * errno, free up the current structure and the
655				 * structures already allocated.
656				 */
657mem1:				saved_errno = errno;
658				if (p)
659					free(p);
660				fts_lfree(head);
661				(void)closedir(dirp);
662				errno = saved_errno;
663				cur->fts_info = FTS_ERR;
664				SET(FTS_STOP);
665				return (NULL);
666			}
667			adjaddr = sp->fts_path;
668			maxlen = sp->fts_pathlen - sp->fts_cur->fts_pathlen - 1;
669		}
670
671		p->fts_pathlen = len + dp->d_namlen + 1;
672		p->fts_parent = sp->fts_cur;
673		p->fts_level = level;
674
675		if (cderrno) {
676			if (nlinks) {
677				p->fts_info = FTS_NS;
678				p->fts_errno = cderrno;
679			} else
680				p->fts_info = FTS_NSOK;
681			p->fts_accpath = cur->fts_accpath;
682		} else if (nlinks == 0
683#ifdef DT_DIR
684		    || nlinks > 0 &&
685		    dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN
686#endif
687		    ) {
688			p->fts_accpath =
689			    ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
690			p->fts_info = FTS_NSOK;
691		} else {
692			/* Build a file name for fts_stat to stat. */
693			if (ISSET(FTS_NOCHDIR)) {
694				p->fts_accpath = p->fts_path;
695				memmove(cp, p->fts_name, p->fts_namelen + 1);
696			} else
697				p->fts_accpath = p->fts_name;
698			/* Stat it. */
699			p->fts_info = fts_stat(sp, p, 0);
700
701			/* Decrement link count if applicable. */
702			if (nlinks > 0 && (p->fts_info == FTS_D ||
703			    p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
704				--nlinks;
705		}
706
707		/* We walk in directory order so "ls -f" doesn't get upset. */
708		p->fts_link = NULL;
709		if (head == NULL)
710			head = tail = p;
711		else {
712			tail->fts_link = p;
713			tail = p;
714		}
715		++nitems;
716	}
717	(void)closedir(dirp);
718
719	/*
720	 * If had to realloc the path, adjust the addresses for the rest
721	 * of the tree.
722	 */
723	if (adjaddr)
724		fts_padjust(sp, adjaddr);
725
726	/*
727	 * If not changing directories, reset the path back to original
728	 * state.
729	 */
730	if (ISSET(FTS_NOCHDIR)) {
731		if (cp - 1 > sp->fts_path)
732			--cp;
733		*cp = '\0';
734	}
735
736	/*
737	 * If descended after called from fts_children or after called from
738	 * fts_read and nothing found, get back.  At the root level we use
739	 * the saved fd; if one of fts_open()'s arguments is a relative path
740	 * to an empty directory, we wind up here with no other way back.  If
741	 * can't get back, we're done.
742	 */
743	if (descend && (type == BCHILD || !nitems) &&
744	    (cur->fts_level == FTS_ROOTLEVEL ?
745	    FCHDIR(sp, sp->fts_rfd) : CHDIR(sp, ".."))) {
746		cur->fts_info = FTS_ERR;
747		SET(FTS_STOP);
748		return (NULL);
749	}
750
751	/* If didn't find anything, return NULL. */
752	if (!nitems) {
753		if (type == BREAD)
754			cur->fts_info = FTS_DP;
755		return (NULL);
756	}
757
758	/* Sort the entries. */
759	if (sp->fts_compar && nitems > 1)
760		head = fts_sort(sp, head, nitems);
761	return (head);
762}
763
764static u_short
765fts_stat(sp, p, follow)
766	FTS *sp;
767	register FTSENT *p;
768	int follow;
769{
770	register FTSENT *t;
771	register dev_t dev;
772	register ino_t ino;
773	struct stat *sbp, sb;
774	int saved_errno;
775
776	/* If user needs stat info, stat buffer already allocated. */
777	sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
778
779	/*
780	 * If doing a logical walk, or application requested FTS_FOLLOW, do
781	 * a stat(2).  If that fails, check for a non-existent symlink.  If
782	 * fail, set the errno from the stat call.
783	 */
784	if (ISSET(FTS_LOGICAL) || follow) {
785		if (stat(p->fts_accpath, sbp)) {
786			saved_errno = errno;
787			if (!lstat(p->fts_accpath, sbp)) {
788				errno = 0;
789				return (FTS_SLNONE);
790			}
791			p->fts_errno = saved_errno;
792			goto err;
793		}
794	} else if (lstat(p->fts_accpath, sbp)) {
795		p->fts_errno = errno;
796err:		memset(sbp, 0, sizeof(struct stat));
797		return (FTS_NS);
798	}
799
800	if (S_ISDIR(sbp->st_mode)) {
801		/*
802		 * Set the device/inode.  Used to find cycles and check for
803		 * crossing mount points.  Also remember the link count, used
804		 * in fts_build to limit the number of stat calls.  It is
805		 * understood that these fields are only referenced if fts_info
806		 * is set to FTS_D.
807		 */
808		dev = p->fts_dev = sbp->st_dev;
809		ino = p->fts_ino = sbp->st_ino;
810		p->fts_nlink = sbp->st_nlink;
811
812		if (ISDOT(p->fts_name))
813			return (FTS_DOT);
814
815		/*
816		 * Cycle detection is done by brute force when the directory
817		 * is first encountered.  If the tree gets deep enough or the
818		 * number of symbolic links to directories is high enough,
819		 * something faster might be worthwhile.
820		 */
821		for (t = p->fts_parent;
822		    t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
823			if (ino == t->fts_ino && dev == t->fts_dev) {
824				p->fts_cycle = t;
825				return (FTS_DC);
826			}
827		return (FTS_D);
828	}
829	if (S_ISLNK(sbp->st_mode))
830		return (FTS_SL);
831	if (S_ISREG(sbp->st_mode))
832		return (FTS_F);
833	return (FTS_DEFAULT);
834}
835
836static FTSENT *
837fts_sort(sp, head, nitems)
838	FTS *sp;
839	FTSENT *head;
840	register int nitems;
841{
842	register FTSENT **ap, *p;
843
844	/*
845	 * Construct an array of pointers to the structures and call qsort(3).
846	 * Reassemble the array in the order returned by qsort.  If unable to
847	 * sort for memory reasons, return the directory entries in their
848	 * current order.  Allocate enough space for the current needs plus
849	 * 40 so don't realloc one entry at a time.
850	 */
851	if (nitems > sp->fts_nitems) {
852		sp->fts_nitems = nitems + 40;
853		if ((sp->fts_array = realloc(sp->fts_array,
854		    (size_t)(sp->fts_nitems * sizeof(FTSENT *)))) == NULL) {
855			sp->fts_nitems = 0;
856			return (head);
857		}
858	}
859	for (ap = sp->fts_array, p = head; p; p = p->fts_link)
860		*ap++ = p;
861	qsort((void *)sp->fts_array, nitems, sizeof(FTSENT *), sp->fts_compar);
862	for (head = *(ap = sp->fts_array); --nitems; ++ap)
863		ap[0]->fts_link = ap[1];
864	ap[0]->fts_link = NULL;
865	return (head);
866}
867
868static FTSENT *
869fts_alloc(sp, name, namelen)
870	FTS *sp;
871	char *name;
872	register int namelen;
873{
874	register FTSENT *p;
875	size_t len;
876
877	/*
878	 * The file name is a variable length array and no stat structure is
879	 * necessary if the user has set the nostat bit.  Allocate the FTSENT
880	 * structure, the file name and the stat structure in one chunk, but
881	 * be careful that the stat structure is reasonably aligned.  Since the
882	 * fts_name field is declared to be of size 1, the fts_name pointer is
883	 * namelen + 2 before the first possible address of the stat structure.
884	 */
885	len = sizeof(FTSENT) + namelen;
886	if (!ISSET(FTS_NOSTAT))
887		len += sizeof(struct stat) + ALIGNBYTES;
888	if ((p = malloc(len)) == NULL)
889		return (NULL);
890
891	/* Copy the name plus the trailing NULL. */
892	memmove(p->fts_name, name, namelen + 1);
893
894	if (!ISSET(FTS_NOSTAT))
895		p->fts_statp = (struct stat *)ALIGN(p->fts_name + namelen + 2);
896	p->fts_namelen = namelen;
897	p->fts_path = sp->fts_path;
898	p->fts_errno = 0;
899	p->fts_flags = 0;
900	p->fts_instr = FTS_NOINSTR;
901	p->fts_number = 0;
902	p->fts_pointer = NULL;
903	return (p);
904}
905
906static void
907fts_lfree(head)
908	register FTSENT *head;
909{
910	register FTSENT *p;
911
912	/* Free a linked list of structures. */
913	while (p = head) {
914		head = head->fts_link;
915		free(p);
916	}
917}
918
919/*
920 * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
921 * Most systems will allow creation of paths much longer than MAXPATHLEN, even
922 * though the kernel won't resolve them.  Add the size (not just what's needed)
923 * plus 256 bytes so don't realloc the path 2 bytes at a time.
924 */
925static int
926fts_palloc(sp, more)
927	FTS *sp;
928	size_t more;
929{
930	sp->fts_pathlen += more + 256;
931	sp->fts_path = realloc(sp->fts_path, (size_t)sp->fts_pathlen);
932	return (sp->fts_path == NULL);
933}
934
935/*
936 * When the path is realloc'd, have to fix all of the pointers in structures
937 * already returned.
938 */
939static void
940fts_padjust(sp, addr)
941	FTS *sp;
942	void *addr;
943{
944	FTSENT *p;
945
946#define	ADJUST(p) {							\
947	(p)->fts_accpath =						\
948	    (char *)addr + ((p)->fts_accpath - (p)->fts_path);		\
949	(p)->fts_path = addr;						\
950}
951	/* Adjust the current set of children. */
952	for (p = sp->fts_child; p; p = p->fts_link)
953		ADJUST(p);
954
955	/* Adjust the rest of the tree. */
956	for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
957		ADJUST(p);
958		p = p->fts_link ? p->fts_link : p->fts_parent;
959	}
960}
961
962static size_t
963fts_maxarglen(argv)
964	char * const *argv;
965{
966	size_t len, max;
967
968	for (max = 0; *argv; ++argv)
969		if ((len = strlen(*argv)) > max)
970			max = len;
971	return (max);
972}
973