xref: /freebsd/lib/libc/gen/fts-compat.c (revision 1c05a6ea6b849ff95e539c31adea887c644a6a01)
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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  * $OpenBSD: fts.c,v 1.22 1999/10/03 19:22:22 millert Exp $
30  */
31 
32 #if 0
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)fts.c	8.6 (Berkeley) 8/14/94";
35 #endif /* LIBC_SCCS and not lint */
36 #endif
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #include "namespace.h"
42 #include <sys/param.h>
43 #define	_WANT_FREEBSD11_STATFS
44 #include <sys/mount.h>
45 #define	_WANT_FREEBSD11_STAT
46 #include <sys/stat.h>
47 
48 #define	_WANT_FREEBSD11_DIRENT
49 #include <dirent.h>
50 #include <errno.h>
51 #include <fcntl.h>
52 #include <stdlib.h>
53 #include <string.h>
54 #include <unistd.h>
55 #include "gen-compat.h"
56 #include "fts-compat.h"
57 #include "un-namespace.h"
58 
59 #include "gen-private.h"
60 
61 FTSENT	*__fts_children_44bsd(FTS *, int);
62 int	 __fts_close_44bsd(FTS *);
63 void	*__fts_get_clientptr_44bsd(FTS *);
64 FTS	*__fts_get_stream_44bsd(FTSENT *);
65 FTS	*__fts_open_44bsd(char * const *, int,
66 	    int (*)(const FTSENT * const *, const FTSENT * const *));
67 FTSENT	*__fts_read_44bsd(FTS *);
68 int	 __fts_set_44bsd(FTS *, FTSENT *, int);
69 void	 __fts_set_clientptr_44bsd(FTS *, void *);
70 
71 static FTSENT	*fts_alloc(FTS *, char *, int);
72 static FTSENT	*fts_build(FTS *, int);
73 static void	 fts_lfree(FTSENT *);
74 static void	 fts_load(FTS *, FTSENT *);
75 static size_t	 fts_maxarglen(char * const *);
76 static void	 fts_padjust(FTS *, FTSENT *);
77 static int	 fts_palloc(FTS *, size_t);
78 static FTSENT	*fts_sort(FTS *, FTSENT *, int);
79 static u_short	 fts_stat(FTS *, FTSENT *, int);
80 static int	 fts_safe_changedir(FTS *, FTSENT *, int, char *);
81 static int	 fts_ufslinks(FTS *, const FTSENT *);
82 
83 #define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
84 
85 #define	CLR(opt)	(sp->fts_options &= ~(opt))
86 #define	ISSET(opt)	(sp->fts_options & (opt))
87 #define	SET(opt)	(sp->fts_options |= (opt))
88 
89 #define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
90 
91 /* fts_build flags */
92 #define	BCHILD		1		/* fts_children */
93 #define	BNAMES		2		/* fts_children, names only */
94 #define	BREAD		3		/* fts_read */
95 
96 /*
97  * Internal representation of an FTS, including extra implementation
98  * details.  The FTS returned from fts_open points to this structure's
99  * ftsp_fts member (and can be cast to an _fts_private as required)
100  */
101 struct _fts_private {
102 	FTS		ftsp_fts;
103 	struct freebsd11_statfs	ftsp_statfs;
104 	uint32_t	ftsp_dev;
105 	int		ftsp_linksreliable;
106 };
107 
108 /*
109  * The "FTS_NOSTAT" option can avoid a lot of calls to stat(2) if it
110  * knows that a directory could not possibly have subdirectories.  This
111  * is decided by looking at the link count: a subdirectory would
112  * increment its parent's link count by virtue of its own ".." entry.
113  * This assumption only holds for UFS-like filesystems that implement
114  * links and directories this way, so we must punt for others.
115  */
116 
117 static const char *ufslike_filesystems[] = {
118 	"ufs",
119 	"zfs",
120 	"nfs",
121 	"ext2fs",
122 	0
123 };
124 
125 FTS *
126 __fts_open_44bsd(char * const *argv, int options,
127     int (*compar)(const FTSENT * const *, const FTSENT * const *))
128 {
129 	struct _fts_private *priv;
130 	FTS *sp;
131 	FTSENT *p, *root;
132 	int nitems;
133 	FTSENT *parent, *tmp;
134 	int len;
135 
136 	/* Options check. */
137 	if (options & ~FTS_OPTIONMASK) {
138 		errno = EINVAL;
139 		return (NULL);
140 	}
141 
142 	/* Allocate/initialize the stream. */
143 	if ((priv = calloc(1, sizeof(*priv))) == NULL)
144 		return (NULL);
145 	sp = &priv->ftsp_fts;
146 	sp->fts_compar = compar;
147 	sp->fts_options = options;
148 
149 	/* Logical walks turn on NOCHDIR; symbolic links are too hard. */
150 	if (ISSET(FTS_LOGICAL))
151 		SET(FTS_NOCHDIR);
152 
153 	/*
154 	 * Start out with 1K of path space, and enough, in any case,
155 	 * to hold the user's paths.
156 	 */
157 	if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
158 		goto mem1;
159 
160 	/* Allocate/initialize root's parent. */
161 	if ((parent = fts_alloc(sp, "", 0)) == NULL)
162 		goto mem2;
163 	parent->fts_level = FTS_ROOTPARENTLEVEL;
164 
165 	/* Shush, GCC. */
166 	tmp = NULL;
167 
168 	/* Allocate/initialize root(s). */
169 	for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
170 		/* Don't allow zero-length paths. */
171 		if ((len = strlen(*argv)) == 0) {
172 			errno = ENOENT;
173 			goto mem3;
174 		}
175 
176 		p = fts_alloc(sp, *argv, len);
177 		p->fts_level = FTS_ROOTLEVEL;
178 		p->fts_parent = parent;
179 		p->fts_accpath = p->fts_name;
180 		p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW));
181 
182 		/* Command-line "." and ".." are real directories. */
183 		if (p->fts_info == FTS_DOT)
184 			p->fts_info = FTS_D;
185 
186 		/*
187 		 * If comparison routine supplied, traverse in sorted
188 		 * order; otherwise traverse in the order specified.
189 		 */
190 		if (compar) {
191 			p->fts_link = root;
192 			root = p;
193 		} else {
194 			p->fts_link = NULL;
195 			if (root == NULL)
196 				tmp = root = p;
197 			else {
198 				tmp->fts_link = p;
199 				tmp = p;
200 			}
201 		}
202 	}
203 	if (compar && nitems > 1)
204 		root = fts_sort(sp, root, nitems);
205 
206 	/*
207 	 * Allocate a dummy pointer and make fts_read think that we've just
208 	 * finished the node before the root(s); set p->fts_info to FTS_INIT
209 	 * so that everything about the "current" node is ignored.
210 	 */
211 	if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
212 		goto mem3;
213 	sp->fts_cur->fts_link = root;
214 	sp->fts_cur->fts_info = FTS_INIT;
215 
216 	/*
217 	 * If using chdir(2), grab a file descriptor pointing to dot to ensure
218 	 * that we can get back here; this could be avoided for some paths,
219 	 * but almost certainly not worth the effort.  Slashes, symbolic links,
220 	 * and ".." are all fairly nasty problems.  Note, if we can't get the
221 	 * descriptor we run anyway, just more slowly.
222 	 */
223 	if (!ISSET(FTS_NOCHDIR) &&
224 	    (sp->fts_rfd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
225 		SET(FTS_NOCHDIR);
226 
227 	return (sp);
228 
229 mem3:	fts_lfree(root);
230 	free(parent);
231 mem2:	free(sp->fts_path);
232 mem1:	free(sp);
233 	return (NULL);
234 }
235 
236 static void
237 fts_load(FTS *sp, FTSENT *p)
238 {
239 	int len;
240 	char *cp;
241 
242 	/*
243 	 * Load the stream structure for the next traversal.  Since we don't
244 	 * actually enter the directory until after the preorder visit, set
245 	 * the fts_accpath field specially so the chdir gets done to the right
246 	 * place and the user can access the first node.  From fts_open it's
247 	 * known that the path will fit.
248 	 */
249 	len = p->fts_pathlen = p->fts_namelen;
250 	memmove(sp->fts_path, p->fts_name, len + 1);
251 	if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
252 		len = strlen(++cp);
253 		memmove(p->fts_name, cp, len + 1);
254 		p->fts_namelen = len;
255 	}
256 	p->fts_accpath = p->fts_path = sp->fts_path;
257 	sp->fts_dev = p->fts_dev;
258 }
259 
260 int
261 __fts_close_44bsd(FTS *sp)
262 {
263 	FTSENT *freep, *p;
264 	int saved_errno;
265 
266 	/*
267 	 * This still works if we haven't read anything -- the dummy structure
268 	 * points to the root list, so we step through to the end of the root
269 	 * list which has a valid parent pointer.
270 	 */
271 	if (sp->fts_cur) {
272 		for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
273 			freep = p;
274 			p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
275 			free(freep);
276 		}
277 		free(p);
278 	}
279 
280 	/* Free up child linked list, sort array, path buffer. */
281 	if (sp->fts_child)
282 		fts_lfree(sp->fts_child);
283 	if (sp->fts_array)
284 		free(sp->fts_array);
285 	free(sp->fts_path);
286 
287 	/* Return to original directory, save errno if necessary. */
288 	if (!ISSET(FTS_NOCHDIR)) {
289 		saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
290 		(void)_close(sp->fts_rfd);
291 
292 		/* Set errno and return. */
293 		if (saved_errno != 0) {
294 			/* Free up the stream pointer. */
295 			free(sp);
296 			errno = saved_errno;
297 			return (-1);
298 		}
299 	}
300 
301 	/* Free up the stream pointer. */
302 	free(sp);
303 	return (0);
304 }
305 
306 /*
307  * Special case of "/" at the end of the path so that slashes aren't
308  * appended which would cause paths to be written as "....//foo".
309  */
310 #define	NAPPEND(p)							\
311 	(p->fts_path[p->fts_pathlen - 1] == '/'				\
312 	    ? p->fts_pathlen - 1 : p->fts_pathlen)
313 
314 FTSENT *
315 __fts_read_44bsd(FTS *sp)
316 {
317 	FTSENT *p, *tmp;
318 	int instr;
319 	char *t;
320 	int saved_errno;
321 
322 	/* If finished or unrecoverable error, return NULL. */
323 	if (sp->fts_cur == NULL || ISSET(FTS_STOP))
324 		return (NULL);
325 
326 	/* Set current node pointer. */
327 	p = sp->fts_cur;
328 
329 	/* Save and zero out user instructions. */
330 	instr = p->fts_instr;
331 	p->fts_instr = FTS_NOINSTR;
332 
333 	/* Any type of file may be re-visited; re-stat and re-turn. */
334 	if (instr == FTS_AGAIN) {
335 		p->fts_info = fts_stat(sp, p, 0);
336 		return (p);
337 	}
338 
339 	/*
340 	 * Following a symlink -- SLNONE test allows application to see
341 	 * SLNONE and recover.  If indirecting through a symlink, have
342 	 * keep a pointer to current location.  If unable to get that
343 	 * pointer, follow fails.
344 	 */
345 	if (instr == FTS_FOLLOW &&
346 	    (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
347 		p->fts_info = fts_stat(sp, p, 1);
348 		if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
349 			if ((p->fts_symfd = _open(".", O_RDONLY | O_CLOEXEC,
350 			    0)) < 0) {
351 				p->fts_errno = errno;
352 				p->fts_info = FTS_ERR;
353 			} else
354 				p->fts_flags |= FTS_SYMFOLLOW;
355 		}
356 		return (p);
357 	}
358 
359 	/* Directory in pre-order. */
360 	if (p->fts_info == FTS_D) {
361 		/* If skipped or crossed mount point, do post-order visit. */
362 		if (instr == FTS_SKIP ||
363 		    (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
364 			if (p->fts_flags & FTS_SYMFOLLOW)
365 				(void)_close(p->fts_symfd);
366 			if (sp->fts_child) {
367 				fts_lfree(sp->fts_child);
368 				sp->fts_child = NULL;
369 			}
370 			p->fts_info = FTS_DP;
371 			return (p);
372 		}
373 
374 		/* Rebuild if only read the names and now traversing. */
375 		if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
376 			CLR(FTS_NAMEONLY);
377 			fts_lfree(sp->fts_child);
378 			sp->fts_child = NULL;
379 		}
380 
381 		/*
382 		 * Cd to the subdirectory.
383 		 *
384 		 * If have already read and now fail to chdir, whack the list
385 		 * to make the names come out right, and set the parent errno
386 		 * so the application will eventually get an error condition.
387 		 * Set the FTS_DONTCHDIR flag so that when we logically change
388 		 * directories back to the parent we don't do a chdir.
389 		 *
390 		 * If haven't read do so.  If the read fails, fts_build sets
391 		 * FTS_STOP or the fts_info field of the node.
392 		 */
393 		if (sp->fts_child != NULL) {
394 			if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
395 				p->fts_errno = errno;
396 				p->fts_flags |= FTS_DONTCHDIR;
397 				for (p = sp->fts_child; p != NULL;
398 				    p = p->fts_link)
399 					p->fts_accpath =
400 					    p->fts_parent->fts_accpath;
401 			}
402 		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
403 			if (ISSET(FTS_STOP))
404 				return (NULL);
405 			return (p);
406 		}
407 		p = sp->fts_child;
408 		sp->fts_child = NULL;
409 		goto name;
410 	}
411 
412 	/* Move to the next node on this level. */
413 next:	tmp = p;
414 	if ((p = p->fts_link) != NULL) {
415 		free(tmp);
416 
417 		/*
418 		 * If reached the top, return to the original directory (or
419 		 * the root of the tree), and load the paths for the next root.
420 		 */
421 		if (p->fts_level == FTS_ROOTLEVEL) {
422 			if (FCHDIR(sp, sp->fts_rfd)) {
423 				SET(FTS_STOP);
424 				return (NULL);
425 			}
426 			fts_load(sp, p);
427 			return (sp->fts_cur = p);
428 		}
429 
430 		/*
431 		 * User may have called fts_set on the node.  If skipped,
432 		 * ignore.  If followed, get a file descriptor so we can
433 		 * get back if necessary.
434 		 */
435 		if (p->fts_instr == FTS_SKIP)
436 			goto next;
437 		if (p->fts_instr == FTS_FOLLOW) {
438 			p->fts_info = fts_stat(sp, p, 1);
439 			if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
440 				if ((p->fts_symfd =
441 				    _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0) {
442 					p->fts_errno = errno;
443 					p->fts_info = FTS_ERR;
444 				} else
445 					p->fts_flags |= FTS_SYMFOLLOW;
446 			}
447 			p->fts_instr = FTS_NOINSTR;
448 		}
449 
450 name:		t = sp->fts_path + NAPPEND(p->fts_parent);
451 		*t++ = '/';
452 		memmove(t, p->fts_name, p->fts_namelen + 1);
453 		return (sp->fts_cur = p);
454 	}
455 
456 	/* Move up to the parent node. */
457 	p = tmp->fts_parent;
458 	free(tmp);
459 
460 	if (p->fts_level == FTS_ROOTPARENTLEVEL) {
461 		/*
462 		 * Done; free everything up and set errno to 0 so the user
463 		 * can distinguish between error and EOF.
464 		 */
465 		free(p);
466 		errno = 0;
467 		return (sp->fts_cur = NULL);
468 	}
469 
470 	/* NUL terminate the pathname. */
471 	sp->fts_path[p->fts_pathlen] = '\0';
472 
473 	/*
474 	 * Return to the parent directory.  If at a root node or came through
475 	 * a symlink, go back through the file descriptor.  Otherwise, cd up
476 	 * one directory.
477 	 */
478 	if (p->fts_level == FTS_ROOTLEVEL) {
479 		if (FCHDIR(sp, sp->fts_rfd)) {
480 			SET(FTS_STOP);
481 			return (NULL);
482 		}
483 	} else if (p->fts_flags & FTS_SYMFOLLOW) {
484 		if (FCHDIR(sp, p->fts_symfd)) {
485 			saved_errno = errno;
486 			(void)_close(p->fts_symfd);
487 			errno = saved_errno;
488 			SET(FTS_STOP);
489 			return (NULL);
490 		}
491 		(void)_close(p->fts_symfd);
492 	} else if (!(p->fts_flags & FTS_DONTCHDIR) &&
493 	    fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
494 		SET(FTS_STOP);
495 		return (NULL);
496 	}
497 	p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
498 	return (sp->fts_cur = p);
499 }
500 
501 /*
502  * Fts_set takes the stream as an argument although it's not used in this
503  * implementation; it would be necessary if anyone wanted to add global
504  * semantics to fts using fts_set.  An error return is allowed for similar
505  * reasons.
506  */
507 /* ARGSUSED */
508 int
509 __fts_set_44bsd(FTS *sp, FTSENT *p, int instr)
510 {
511 	if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
512 	    instr != FTS_NOINSTR && instr != FTS_SKIP) {
513 		errno = EINVAL;
514 		return (1);
515 	}
516 	p->fts_instr = instr;
517 	return (0);
518 }
519 
520 FTSENT *
521 __fts_children_44bsd(FTS *sp, int instr)
522 {
523 	FTSENT *p;
524 	int fd;
525 
526 	if (instr != 0 && instr != FTS_NAMEONLY) {
527 		errno = EINVAL;
528 		return (NULL);
529 	}
530 
531 	/* Set current node pointer. */
532 	p = sp->fts_cur;
533 
534 	/*
535 	 * Errno set to 0 so user can distinguish empty directory from
536 	 * an error.
537 	 */
538 	errno = 0;
539 
540 	/* Fatal errors stop here. */
541 	if (ISSET(FTS_STOP))
542 		return (NULL);
543 
544 	/* Return logical hierarchy of user's arguments. */
545 	if (p->fts_info == FTS_INIT)
546 		return (p->fts_link);
547 
548 	/*
549 	 * If not a directory being visited in pre-order, stop here.  Could
550 	 * allow FTS_DNR, assuming the user has fixed the problem, but the
551 	 * same effect is available with FTS_AGAIN.
552 	 */
553 	if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
554 		return (NULL);
555 
556 	/* Free up any previous child list. */
557 	if (sp->fts_child != NULL)
558 		fts_lfree(sp->fts_child);
559 
560 	if (instr == FTS_NAMEONLY) {
561 		SET(FTS_NAMEONLY);
562 		instr = BNAMES;
563 	} else
564 		instr = BCHILD;
565 
566 	/*
567 	 * If using chdir on a relative path and called BEFORE fts_read does
568 	 * its chdir to the root of a traversal, we can lose -- we need to
569 	 * chdir into the subdirectory, and we don't know where the current
570 	 * directory is, so we can't get back so that the upcoming chdir by
571 	 * fts_read will work.
572 	 */
573 	if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
574 	    ISSET(FTS_NOCHDIR))
575 		return (sp->fts_child = fts_build(sp, instr));
576 
577 	if ((fd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
578 		return (NULL);
579 	sp->fts_child = fts_build(sp, instr);
580 	if (fchdir(fd)) {
581 		(void)_close(fd);
582 		return (NULL);
583 	}
584 	(void)_close(fd);
585 	return (sp->fts_child);
586 }
587 
588 #ifndef fts_get_clientptr
589 #error "fts_get_clientptr not defined"
590 #endif
591 
592 void *
593 (__fts_get_clientptr_44bsd)(FTS *sp)
594 {
595 
596 	return (fts_get_clientptr(sp));
597 }
598 
599 #ifndef fts_get_stream
600 #error "fts_get_stream not defined"
601 #endif
602 
603 FTS *
604 (__fts_get_stream_44bsd)(FTSENT *p)
605 {
606 	return (fts_get_stream(p));
607 }
608 
609 void
610 __fts_set_clientptr_44bsd(FTS *sp, void *clientptr)
611 {
612 
613 	sp->fts_clientptr = clientptr;
614 }
615 
616 /*
617  * This is the tricky part -- do not casually change *anything* in here.  The
618  * idea is to build the linked list of entries that are used by fts_children
619  * and fts_read.  There are lots of special cases.
620  *
621  * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
622  * set and it's a physical walk (so that symbolic links can't be directories),
623  * we can do things quickly.  First, if it's a 4.4BSD file system, the type
624  * of the file is in the directory entry.  Otherwise, we assume that the number
625  * of subdirectories in a node is equal to the number of links to the parent.
626  * The former skips all stat calls.  The latter skips stat calls in any leaf
627  * directories and for any files after the subdirectories in the directory have
628  * been found, cutting the stat calls by about 2/3.
629  */
630 static FTSENT *
631 fts_build(FTS *sp, int type)
632 {
633 	struct freebsd11_dirent *dp;
634 	FTSENT *p, *head;
635 	int nitems;
636 	FTSENT *cur, *tail;
637 	DIR *dirp;
638 	void *oldaddr;
639 	size_t dnamlen;
640 	int cderrno, descend, len, level, maxlen, nlinks, oflag, saved_errno,
641 	    nostat, doadjust;
642 	char *cp;
643 
644 	/* Set current node pointer. */
645 	cur = sp->fts_cur;
646 
647 	/*
648 	 * Open the directory for reading.  If this fails, we're done.
649 	 * If being called from fts_read, set the fts_info field.
650 	 */
651 #ifdef FTS_WHITEOUT
652 	if (ISSET(FTS_WHITEOUT))
653 		oflag = DTF_NODUP | DTF_REWIND;
654 	else
655 		oflag = DTF_HIDEW | DTF_NODUP | DTF_REWIND;
656 #else
657 #define __opendir2(path, flag) opendir(path)
658 #endif
659 	if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
660 		if (type == BREAD) {
661 			cur->fts_info = FTS_DNR;
662 			cur->fts_errno = errno;
663 		}
664 		return (NULL);
665 	}
666 
667 	/*
668 	 * Nlinks is the number of possible entries of type directory in the
669 	 * directory if we're cheating on stat calls, 0 if we're not doing
670 	 * any stat calls at all, -1 if we're doing stats on everything.
671 	 */
672 	if (type == BNAMES) {
673 		nlinks = 0;
674 		/* Be quiet about nostat, GCC. */
675 		nostat = 0;
676 	} else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL)) {
677 		if (fts_ufslinks(sp, cur))
678 			nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
679 		else
680 			nlinks = -1;
681 		nostat = 1;
682 	} else {
683 		nlinks = -1;
684 		nostat = 0;
685 	}
686 
687 #ifdef notdef
688 	(void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
689 	(void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
690 	    ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
691 #endif
692 	/*
693 	 * If we're going to need to stat anything or we want to descend
694 	 * and stay in the directory, chdir.  If this fails we keep going,
695 	 * but set a flag so we don't chdir after the post-order visit.
696 	 * We won't be able to stat anything, but we can still return the
697 	 * names themselves.  Note, that since fts_read won't be able to
698 	 * chdir into the directory, it will have to return different path
699 	 * names than before, i.e. "a/b" instead of "b".  Since the node
700 	 * has already been visited in pre-order, have to wait until the
701 	 * post-order visit to return the error.  There is a special case
702 	 * here, if there was nothing to stat then it's not an error to
703 	 * not be able to stat.  This is all fairly nasty.  If a program
704 	 * needed sorted entries or stat information, they had better be
705 	 * checking FTS_NS on the returned nodes.
706 	 */
707 	cderrno = 0;
708 	if (nlinks || type == BREAD) {
709 		if (fts_safe_changedir(sp, cur, _dirfd(dirp), NULL)) {
710 			if (nlinks && type == BREAD)
711 				cur->fts_errno = errno;
712 			cur->fts_flags |= FTS_DONTCHDIR;
713 			descend = 0;
714 			cderrno = errno;
715 		} else
716 			descend = 1;
717 	} else
718 		descend = 0;
719 
720 	/*
721 	 * Figure out the max file name length that can be stored in the
722 	 * current path -- the inner loop allocates more path as necessary.
723 	 * We really wouldn't have to do the maxlen calculations here, we
724 	 * could do them in fts_read before returning the path, but it's a
725 	 * lot easier here since the length is part of the dirent structure.
726 	 *
727 	 * If not changing directories set a pointer so that can just append
728 	 * each new name into the path.
729 	 */
730 	len = NAPPEND(cur);
731 	if (ISSET(FTS_NOCHDIR)) {
732 		cp = sp->fts_path + len;
733 		*cp++ = '/';
734 	} else {
735 		/* GCC, you're too verbose. */
736 		cp = NULL;
737 	}
738 	len++;
739 	maxlen = sp->fts_pathlen - len;
740 
741 	level = cur->fts_level + 1;
742 
743 	/* Read the directory, attaching each entry to the `link' pointer. */
744 	doadjust = 0;
745 	for (head = tail = NULL, nitems = 0;
746 	    dirp && (dp = freebsd11_readdir(dirp));) {
747 		dnamlen = dp->d_namlen;
748 		if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
749 			continue;
750 
751 		if ((p = fts_alloc(sp, dp->d_name, (int)dnamlen)) == NULL)
752 			goto mem1;
753 		if (dnamlen >= maxlen) {	/* include space for NUL */
754 			oldaddr = sp->fts_path;
755 			if (fts_palloc(sp, dnamlen + len + 1)) {
756 				/*
757 				 * No more memory for path or structures.  Save
758 				 * errno, free up the current structure and the
759 				 * structures already allocated.
760 				 */
761 mem1:				saved_errno = errno;
762 				if (p)
763 					free(p);
764 				fts_lfree(head);
765 				(void)closedir(dirp);
766 				cur->fts_info = FTS_ERR;
767 				SET(FTS_STOP);
768 				errno = saved_errno;
769 				return (NULL);
770 			}
771 			/* Did realloc() change the pointer? */
772 			if (oldaddr != sp->fts_path) {
773 				doadjust = 1;
774 				if (ISSET(FTS_NOCHDIR))
775 					cp = sp->fts_path + len;
776 			}
777 			maxlen = sp->fts_pathlen - len;
778 		}
779 
780 		if (len + dnamlen >= USHRT_MAX) {
781 			/*
782 			 * In an FTSENT, fts_pathlen is a u_short so it is
783 			 * possible to wraparound here.  If we do, free up
784 			 * the current structure and the structures already
785 			 * allocated, then error out with ENAMETOOLONG.
786 			 */
787 			free(p);
788 			fts_lfree(head);
789 			(void)closedir(dirp);
790 			cur->fts_info = FTS_ERR;
791 			SET(FTS_STOP);
792 			errno = ENAMETOOLONG;
793 			return (NULL);
794 		}
795 		p->fts_level = level;
796 		p->fts_parent = sp->fts_cur;
797 		p->fts_pathlen = len + dnamlen;
798 
799 #ifdef FTS_WHITEOUT
800 		if (dp->d_type == DT_WHT)
801 			p->fts_flags |= FTS_ISW;
802 #endif
803 
804 		if (cderrno) {
805 			if (nlinks) {
806 				p->fts_info = FTS_NS;
807 				p->fts_errno = cderrno;
808 			} else
809 				p->fts_info = FTS_NSOK;
810 			p->fts_accpath = cur->fts_accpath;
811 		} else if (nlinks == 0
812 #ifdef DT_DIR
813 		    || (nostat &&
814 		    dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN)
815 #endif
816 		    ) {
817 			p->fts_accpath =
818 			    ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
819 			p->fts_info = FTS_NSOK;
820 		} else {
821 			/* Build a file name for fts_stat to stat. */
822 			if (ISSET(FTS_NOCHDIR)) {
823 				p->fts_accpath = p->fts_path;
824 				memmove(cp, p->fts_name, p->fts_namelen + 1);
825 			} else
826 				p->fts_accpath = p->fts_name;
827 			/* Stat it. */
828 			p->fts_info = fts_stat(sp, p, 0);
829 
830 			/* Decrement link count if applicable. */
831 			if (nlinks > 0 && (p->fts_info == FTS_D ||
832 			    p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
833 				--nlinks;
834 		}
835 
836 		/* We walk in directory order so "ls -f" doesn't get upset. */
837 		p->fts_link = NULL;
838 		if (head == NULL)
839 			head = tail = p;
840 		else {
841 			tail->fts_link = p;
842 			tail = p;
843 		}
844 		++nitems;
845 	}
846 	if (dirp)
847 		(void)closedir(dirp);
848 
849 	/*
850 	 * If realloc() changed the address of the path, adjust the
851 	 * addresses for the rest of the tree and the dir list.
852 	 */
853 	if (doadjust)
854 		fts_padjust(sp, head);
855 
856 	/*
857 	 * If not changing directories, reset the path back to original
858 	 * state.
859 	 */
860 	if (ISSET(FTS_NOCHDIR)) {
861 		if (len == sp->fts_pathlen || nitems == 0)
862 			--cp;
863 		*cp = '\0';
864 	}
865 
866 	/*
867 	 * If descended after called from fts_children or after called from
868 	 * fts_read and nothing found, get back.  At the root level we use
869 	 * the saved fd; if one of fts_open()'s arguments is a relative path
870 	 * to an empty directory, we wind up here with no other way back.  If
871 	 * can't get back, we're done.
872 	 */
873 	if (descend && (type == BCHILD || !nitems) &&
874 	    (cur->fts_level == FTS_ROOTLEVEL ?
875 	    FCHDIR(sp, sp->fts_rfd) :
876 	    fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
877 		cur->fts_info = FTS_ERR;
878 		SET(FTS_STOP);
879 		return (NULL);
880 	}
881 
882 	/* If didn't find anything, return NULL. */
883 	if (!nitems) {
884 		if (type == BREAD)
885 			cur->fts_info = FTS_DP;
886 		return (NULL);
887 	}
888 
889 	/* Sort the entries. */
890 	if (sp->fts_compar && nitems > 1)
891 		head = fts_sort(sp, head, nitems);
892 	return (head);
893 }
894 
895 static u_short
896 fts_stat(FTS *sp, FTSENT *p, int follow)
897 {
898 	FTSENT *t;
899 	uint32_t dev;
900 	uint32_t ino;
901 	struct freebsd11_stat *sbp, sb;
902 	int saved_errno;
903 
904 	/* If user needs stat info, stat buffer already allocated. */
905 	sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
906 
907 #ifdef FTS_WHITEOUT
908 	/* Check for whiteout. */
909 	if (p->fts_flags & FTS_ISW) {
910 		if (sbp != &sb) {
911 			memset(sbp, '\0', sizeof(*sbp));
912 			sbp->st_mode = S_IFWHT;
913 		}
914 		return (FTS_W);
915 	}
916 #endif
917 
918 	/*
919 	 * If doing a logical walk, or application requested FTS_FOLLOW, do
920 	 * a stat(2).  If that fails, check for a non-existent symlink.  If
921 	 * fail, set the errno from the stat call.
922 	 */
923 	if (ISSET(FTS_LOGICAL) || follow) {
924 		if (freebsd11_stat(p->fts_accpath, sbp)) {
925 			saved_errno = errno;
926 			if (!freebsd11_lstat(p->fts_accpath, sbp)) {
927 				errno = 0;
928 				return (FTS_SLNONE);
929 			}
930 			p->fts_errno = saved_errno;
931 			goto err;
932 		}
933 	} else if (freebsd11_lstat(p->fts_accpath, sbp)) {
934 		p->fts_errno = errno;
935 err:		memset(sbp, 0, sizeof(struct stat));
936 		return (FTS_NS);
937 	}
938 
939 	if (S_ISDIR(sbp->st_mode)) {
940 		/*
941 		 * Set the device/inode.  Used to find cycles and check for
942 		 * crossing mount points.  Also remember the link count, used
943 		 * in fts_build to limit the number of stat calls.  It is
944 		 * understood that these fields are only referenced if fts_info
945 		 * is set to FTS_D.
946 		 */
947 		dev = p->fts_dev = sbp->st_dev;
948 		ino = p->fts_ino = sbp->st_ino;
949 		p->fts_nlink = sbp->st_nlink;
950 
951 		if (ISDOT(p->fts_name))
952 			return (FTS_DOT);
953 
954 		/*
955 		 * Cycle detection is done by brute force when the directory
956 		 * is first encountered.  If the tree gets deep enough or the
957 		 * number of symbolic links to directories is high enough,
958 		 * something faster might be worthwhile.
959 		 */
960 		for (t = p->fts_parent;
961 		    t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
962 			if (ino == t->fts_ino && dev == t->fts_dev) {
963 				p->fts_cycle = t;
964 				return (FTS_DC);
965 			}
966 		return (FTS_D);
967 	}
968 	if (S_ISLNK(sbp->st_mode))
969 		return (FTS_SL);
970 	if (S_ISREG(sbp->st_mode))
971 		return (FTS_F);
972 	return (FTS_DEFAULT);
973 }
974 
975 /*
976  * The comparison function takes pointers to pointers to FTSENT structures.
977  * Qsort wants a comparison function that takes pointers to void.
978  * (Both with appropriate levels of const-poisoning, of course!)
979  * Use a trampoline function to deal with the difference.
980  */
981 static int
982 fts_compar(const void *a, const void *b)
983 {
984 	FTS *parent;
985 
986 	parent = (*(const FTSENT * const *)a)->fts_fts;
987 	return (*parent->fts_compar)(a, b);
988 }
989 
990 static FTSENT *
991 fts_sort(FTS *sp, FTSENT *head, int nitems)
992 {
993 	FTSENT **ap, *p;
994 
995 	/*
996 	 * Construct an array of pointers to the structures and call qsort(3).
997 	 * Reassemble the array in the order returned by qsort.  If unable to
998 	 * sort for memory reasons, return the directory entries in their
999 	 * current order.  Allocate enough space for the current needs plus
1000 	 * 40 so don't realloc one entry at a time.
1001 	 */
1002 	if (nitems > sp->fts_nitems) {
1003 		sp->fts_nitems = nitems + 40;
1004 		if ((sp->fts_array = reallocf(sp->fts_array,
1005 		    sp->fts_nitems * sizeof(FTSENT *))) == NULL) {
1006 			sp->fts_nitems = 0;
1007 			return (head);
1008 		}
1009 	}
1010 	for (ap = sp->fts_array, p = head; p; p = p->fts_link)
1011 		*ap++ = p;
1012 	qsort(sp->fts_array, nitems, sizeof(FTSENT *), fts_compar);
1013 	for (head = *(ap = sp->fts_array); --nitems; ++ap)
1014 		ap[0]->fts_link = ap[1];
1015 	ap[0]->fts_link = NULL;
1016 	return (head);
1017 }
1018 
1019 static FTSENT *
1020 fts_alloc(FTS *sp, char *name, int namelen)
1021 {
1022 	FTSENT *p;
1023 	size_t len;
1024 
1025 	struct ftsent_withstat {
1026 		FTSENT	ent;
1027 		struct	freebsd11_stat statbuf;
1028 	};
1029 
1030 	/*
1031 	 * The file name is a variable length array and no stat structure is
1032 	 * necessary if the user has set the nostat bit.  Allocate the FTSENT
1033 	 * structure, the file name and the stat structure in one chunk, but
1034 	 * be careful that the stat structure is reasonably aligned.
1035 	 */
1036 	if (ISSET(FTS_NOSTAT))
1037 		len = sizeof(FTSENT) + namelen + 1;
1038 	else
1039 		len = sizeof(struct ftsent_withstat) + namelen + 1;
1040 
1041 	if ((p = malloc(len)) == NULL)
1042 		return (NULL);
1043 
1044 	if (ISSET(FTS_NOSTAT)) {
1045 		p->fts_name = (char *)(p + 1);
1046 		p->fts_statp = NULL;
1047 	} else {
1048 		p->fts_name = (char *)((struct ftsent_withstat *)p + 1);
1049 		p->fts_statp = &((struct ftsent_withstat *)p)->statbuf;
1050 	}
1051 
1052 	/* Copy the name and guarantee NUL termination. */
1053 	memcpy(p->fts_name, name, namelen);
1054 	p->fts_name[namelen] = '\0';
1055 	p->fts_namelen = namelen;
1056 	p->fts_path = sp->fts_path;
1057 	p->fts_errno = 0;
1058 	p->fts_flags = 0;
1059 	p->fts_instr = FTS_NOINSTR;
1060 	p->fts_number = 0;
1061 	p->fts_pointer = NULL;
1062 	p->fts_fts = sp;
1063 	return (p);
1064 }
1065 
1066 static void
1067 fts_lfree(FTSENT *head)
1068 {
1069 	FTSENT *p;
1070 
1071 	/* Free a linked list of structures. */
1072 	while ((p = head)) {
1073 		head = head->fts_link;
1074 		free(p);
1075 	}
1076 }
1077 
1078 /*
1079  * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
1080  * Most systems will allow creation of paths much longer than MAXPATHLEN, even
1081  * though the kernel won't resolve them.  Add the size (not just what's needed)
1082  * plus 256 bytes so don't realloc the path 2 bytes at a time.
1083  */
1084 static int
1085 fts_palloc(FTS *sp, size_t more)
1086 {
1087 
1088 	sp->fts_pathlen += more + 256;
1089 	/*
1090 	 * Check for possible wraparound.  In an FTS, fts_pathlen is
1091 	 * a signed int but in an FTSENT it is an unsigned short.
1092 	 * We limit fts_pathlen to USHRT_MAX to be safe in both cases.
1093 	 */
1094 	if (sp->fts_pathlen < 0 || sp->fts_pathlen >= USHRT_MAX) {
1095 		if (sp->fts_path)
1096 			free(sp->fts_path);
1097 		sp->fts_path = NULL;
1098 		errno = ENAMETOOLONG;
1099 		return (1);
1100 	}
1101 	sp->fts_path = reallocf(sp->fts_path, sp->fts_pathlen);
1102 	return (sp->fts_path == NULL);
1103 }
1104 
1105 /*
1106  * When the path is realloc'd, have to fix all of the pointers in structures
1107  * already returned.
1108  */
1109 static void
1110 fts_padjust(FTS *sp, FTSENT *head)
1111 {
1112 	FTSENT *p;
1113 	char *addr = sp->fts_path;
1114 
1115 #define	ADJUST(p) do {							\
1116 	if ((p)->fts_accpath != (p)->fts_name) {			\
1117 		(p)->fts_accpath =					\
1118 		    (char *)addr + ((p)->fts_accpath - (p)->fts_path);	\
1119 	}								\
1120 	(p)->fts_path = addr;						\
1121 } while (0)
1122 	/* Adjust the current set of children. */
1123 	for (p = sp->fts_child; p; p = p->fts_link)
1124 		ADJUST(p);
1125 
1126 	/* Adjust the rest of the tree, including the current level. */
1127 	for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
1128 		ADJUST(p);
1129 		p = p->fts_link ? p->fts_link : p->fts_parent;
1130 	}
1131 }
1132 
1133 static size_t
1134 fts_maxarglen(char * const *argv)
1135 {
1136 	size_t len, max;
1137 
1138 	for (max = 0; *argv; ++argv)
1139 		if ((len = strlen(*argv)) > max)
1140 			max = len;
1141 	return (max + 1);
1142 }
1143 
1144 /*
1145  * Change to dir specified by fd or p->fts_accpath without getting
1146  * tricked by someone changing the world out from underneath us.
1147  * Assumes p->fts_dev and p->fts_ino are filled in.
1148  */
1149 static int
1150 fts_safe_changedir(FTS *sp, FTSENT *p, int fd, char *path)
1151 {
1152 	int ret, oerrno, newfd;
1153 	struct freebsd11_stat sb;
1154 
1155 	newfd = fd;
1156 	if (ISSET(FTS_NOCHDIR))
1157 		return (0);
1158 	if (fd < 0 && (newfd = _open(path, O_RDONLY | O_CLOEXEC, 0)) < 0)
1159 		return (-1);
1160 	if (freebsd11_fstat(newfd, &sb)) {
1161 		ret = -1;
1162 		goto bail;
1163 	}
1164 	if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
1165 		errno = ENOENT;		/* disinformation */
1166 		ret = -1;
1167 		goto bail;
1168 	}
1169 	ret = fchdir(newfd);
1170 bail:
1171 	oerrno = errno;
1172 	if (fd < 0)
1173 		(void)_close(newfd);
1174 	errno = oerrno;
1175 	return (ret);
1176 }
1177 
1178 /*
1179  * Check if the filesystem for "ent" has UFS-style links.
1180  */
1181 static int
1182 fts_ufslinks(FTS *sp, const FTSENT *ent)
1183 {
1184 	struct _fts_private *priv;
1185 	const char **cpp;
1186 
1187 	priv = (struct _fts_private *)sp;
1188 	/*
1189 	 * If this node's device is different from the previous, grab
1190 	 * the filesystem information, and decide on the reliability
1191 	 * of the link information from this filesystem for stat(2)
1192 	 * avoidance.
1193 	 */
1194 	if (priv->ftsp_dev != ent->fts_dev) {
1195 		if (freebsd11_statfs(ent->fts_path, &priv->ftsp_statfs) != -1) {
1196 			priv->ftsp_dev = ent->fts_dev;
1197 			priv->ftsp_linksreliable = 0;
1198 			for (cpp = ufslike_filesystems; *cpp; cpp++) {
1199 				if (strcmp(priv->ftsp_statfs.f_fstypename,
1200 				    *cpp) == 0) {
1201 					priv->ftsp_linksreliable = 1;
1202 					break;
1203 				}
1204 			}
1205 		} else {
1206 			priv->ftsp_linksreliable = 0;
1207 		}
1208 	}
1209 	return (priv->ftsp_linksreliable);
1210 }
1211 
1212 __sym_compat(fts_open, __fts_open_44bsd, FBSD_1.0);
1213 __sym_compat(fts_close, __fts_close_44bsd, FBSD_1.0);
1214 __sym_compat(fts_read, __fts_read_44bsd, FBSD_1.0);
1215 __sym_compat(fts_set, __fts_set_44bsd, FBSD_1.0);
1216 __sym_compat(fts_children, __fts_children_44bsd, FBSD_1.0);
1217 __sym_compat(fts_get_clientptr, __fts_get_clientptr_44bsd, FBSD_1.0);
1218 __sym_compat(fts_get_stream, __fts_get_stream_44bsd, FBSD_1.0);
1219 __sym_compat(fts_set_clientptr, __fts_set_clientptr_44bsd, FBSD_1.0);
1220