xref: /freebsd/lib/libc/gen/fts-compat11.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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  * From: $OpenBSD: fts.c,v 1.22 1999/10/03 19:22:22 millert Exp $
29  */
30 
31 #include "namespace.h"
32 #include <sys/param.h>
33 #define	_WANT_FREEBSD11_STATFS
34 #include <sys/mount.h>
35 #define	_WANT_FREEBSD11_STAT
36 #include <sys/stat.h>
37 
38 #define	_WANT_FREEBSD11_DIRENT
39 #include <dirent.h>
40 #include <errno.h>
41 #include <fcntl.h>
42 #include <fts.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include "gen-compat.h"
47 #include "fts-compat11.h"
48 #include "un-namespace.h"
49 
50 #include "gen-private.h"
51 
52 static FTSENT11	*fts_alloc(FTS11 *, char *, size_t);
53 static FTSENT11	*fts_build(FTS11 *, int);
54 static void	 fts_lfree(FTSENT11 *);
55 static void	 fts_load(FTS11 *, FTSENT11 *);
56 static size_t	 fts_maxarglen(char * const *);
57 static void	 fts_padjust(FTS11 *, FTSENT11 *);
58 static int	 fts_palloc(FTS11 *, size_t);
59 static FTSENT11	*fts_sort(FTS11 *, FTSENT11 *, size_t);
60 static int	 fts_stat(FTS11 *, FTSENT11 *, int, int);
61 static int	 fts_safe_changedir(FTS11 *, FTSENT11 *, int, char *);
62 static int	 fts_ufslinks(FTS11 *, const FTSENT11 *);
63 
64 #define	ISDOT(a)	(a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
65 
66 #define	CLR(opt)	(sp->fts_options &= ~(opt))
67 #define	ISSET(opt)	(sp->fts_options & (opt))
68 #define	SET(opt)	(sp->fts_options |= (opt))
69 
70 #define	FCHDIR(sp, fd)	(!ISSET(FTS_NOCHDIR) && fchdir(fd))
71 
72 /* fts_build flags */
73 #define	BCHILD		1		/* fts_children */
74 #define	BNAMES		2		/* fts_children, names only */
75 #define	BREAD		3		/* fts_read */
76 
77 /*
78  * Internal representation of an FTS, including extra implementation
79  * details.  The FTS returned from fts_open points to this structure's
80  * ftsp_fts member (and can be cast to an _fts_private as required)
81  */
82 struct _fts_private11 {
83 	FTS11		ftsp_fts;
84 	struct freebsd11_statfs	ftsp_statfs;
85 	uint32_t	ftsp_dev;
86 	int		ftsp_linksreliable;
87 };
88 
89 /*
90  * The "FTS_NOSTAT" option can avoid a lot of calls to stat(2) if it
91  * knows that a directory could not possibly have subdirectories.  This
92  * is decided by looking at the link count: a subdirectory would
93  * increment its parent's link count by virtue of its own ".." entry.
94  * This assumption only holds for UFS-like filesystems that implement
95  * links and directories this way, so we must punt for others.
96  */
97 
98 static const char *ufslike_filesystems[] = {
99 	"ufs",
100 	"zfs",
101 	"nfs",
102 	"ext2fs",
103 	0
104 };
105 
106 FTS11 *
107 freebsd11_fts_open(char * const *argv, int options,
108     int (*compar)(const FTSENT11 * const *, const FTSENT11 * const *))
109 {
110 	struct _fts_private11 *priv;
111 	FTS11 *sp;
112 	FTSENT11 *p, *root;
113 	FTSENT11 *parent, *tmp;
114 	size_t len, nitems;
115 
116 	/* Options check. */
117 	if (options & ~FTS_OPTIONMASK) {
118 		errno = EINVAL;
119 		return (NULL);
120 	}
121 
122 	/* fts_open() requires at least one path */
123 	if (*argv == NULL) {
124 		errno = EINVAL;
125 		return (NULL);
126 	}
127 
128 	/* Allocate/initialize the stream. */
129 	if ((priv = calloc(1, sizeof(*priv))) == NULL)
130 		return (NULL);
131 	sp = &priv->ftsp_fts;
132 	sp->fts_compar = compar;
133 	sp->fts_options = options;
134 
135 	/* Logical walks turn on NOCHDIR; symbolic links are too hard. */
136 	if (ISSET(FTS_LOGICAL))
137 		SET(FTS_NOCHDIR);
138 
139 	/*
140 	 * Start out with 1K of path space, and enough, in any case,
141 	 * to hold the user's paths.
142 	 */
143 	if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
144 		goto mem1;
145 
146 	/* Allocate/initialize root's parent. */
147 	if ((parent = fts_alloc(sp, "", 0)) == NULL)
148 		goto mem2;
149 	parent->fts_level = FTS_ROOTPARENTLEVEL;
150 
151 	/* Shush, GCC. */
152 	tmp = NULL;
153 
154 	/* Allocate/initialize root(s). */
155 	for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
156 		len = strlen(*argv);
157 
158 		p = fts_alloc(sp, *argv, len);
159 		p->fts_level = FTS_ROOTLEVEL;
160 		p->fts_parent = parent;
161 		p->fts_accpath = p->fts_name;
162 		p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW), -1);
163 
164 		/* Command-line "." and ".." are real directories. */
165 		if (p->fts_info == FTS_DOT)
166 			p->fts_info = FTS_D;
167 
168 		/*
169 		 * If comparison routine supplied, traverse in sorted
170 		 * order; otherwise traverse in the order specified.
171 		 */
172 		if (compar) {
173 			p->fts_link = root;
174 			root = p;
175 		} else {
176 			p->fts_link = NULL;
177 			if (root == NULL)
178 				tmp = root = p;
179 			else {
180 				tmp->fts_link = p;
181 				tmp = p;
182 			}
183 		}
184 	}
185 	if (compar && nitems > 1)
186 		root = fts_sort(sp, root, nitems);
187 
188 	/*
189 	 * Allocate a dummy pointer and make fts_read think that we've just
190 	 * finished the node before the root(s); set p->fts_info to FTS_INIT
191 	 * so that everything about the "current" node is ignored.
192 	 */
193 	if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
194 		goto mem3;
195 	sp->fts_cur->fts_link = root;
196 	sp->fts_cur->fts_info = FTS_INIT;
197 
198 	/*
199 	 * If using chdir(2), grab a file descriptor pointing to dot to ensure
200 	 * that we can get back here; this could be avoided for some paths,
201 	 * but almost certainly not worth the effort.  Slashes, symbolic links,
202 	 * and ".." are all fairly nasty problems.  Note, if we can't get the
203 	 * descriptor we run anyway, just more slowly.
204 	 */
205 	if (!ISSET(FTS_NOCHDIR) &&
206 	    (sp->fts_rfd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
207 		SET(FTS_NOCHDIR);
208 
209 	return (sp);
210 
211 mem3:	fts_lfree(root);
212 	free(parent);
213 mem2:	free(sp->fts_path);
214 mem1:	free(sp);
215 	return (NULL);
216 }
217 
218 static void
219 fts_load(FTS11 *sp, FTSENT11 *p)
220 {
221 	size_t len;
222 	char *cp;
223 
224 	/*
225 	 * Load the stream structure for the next traversal.  Since we don't
226 	 * actually enter the directory until after the preorder visit, set
227 	 * the fts_accpath field specially so the chdir gets done to the right
228 	 * place and the user can access the first node.  From fts_open it's
229 	 * known that the path will fit.
230 	 */
231 	len = p->fts_pathlen = p->fts_namelen;
232 	memmove(sp->fts_path, p->fts_name, len + 1);
233 	if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
234 		len = strlen(++cp);
235 		memmove(p->fts_name, cp, len + 1);
236 		p->fts_namelen = len;
237 	}
238 	p->fts_accpath = p->fts_path = sp->fts_path;
239 	sp->fts_dev = p->fts_dev;
240 }
241 
242 int
243 freebsd11_fts_close(FTS11 *sp)
244 {
245 	FTSENT11 *freep, *p;
246 	int saved_errno;
247 
248 	/*
249 	 * This still works if we haven't read anything -- the dummy structure
250 	 * points to the root list, so we step through to the end of the root
251 	 * list which has a valid parent pointer.
252 	 */
253 	if (sp->fts_cur) {
254 		for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
255 			freep = p;
256 			p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
257 			free(freep);
258 		}
259 		free(p);
260 	}
261 
262 	/* Free up child linked list, sort array, path buffer. */
263 	if (sp->fts_child)
264 		fts_lfree(sp->fts_child);
265 	if (sp->fts_array)
266 		free(sp->fts_array);
267 	free(sp->fts_path);
268 
269 	/* Return to original directory, save errno if necessary. */
270 	if (!ISSET(FTS_NOCHDIR)) {
271 		saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
272 		(void)_close(sp->fts_rfd);
273 
274 		/* Set errno and return. */
275 		if (saved_errno != 0) {
276 			/* Free up the stream pointer. */
277 			free(sp);
278 			errno = saved_errno;
279 			return (-1);
280 		}
281 	}
282 
283 	/* Free up the stream pointer. */
284 	free(sp);
285 	return (0);
286 }
287 
288 /*
289  * Special case of "/" at the end of the path so that slashes aren't
290  * appended which would cause paths to be written as "....//foo".
291  */
292 #define	NAPPEND(p)							\
293 	(p->fts_path[p->fts_pathlen - 1] == '/'				\
294 	    ? p->fts_pathlen - 1 : p->fts_pathlen)
295 
296 FTSENT11 *
297 freebsd11_fts_read(FTS11 *sp)
298 {
299 	FTSENT11 *p, *tmp;
300 	int instr;
301 	char *t;
302 	int saved_errno;
303 
304 	/* If finished or unrecoverable error, return NULL. */
305 	if (sp->fts_cur == NULL || ISSET(FTS_STOP))
306 		return (NULL);
307 
308 	/* Set current node pointer. */
309 	p = sp->fts_cur;
310 
311 	/* Save and zero out user instructions. */
312 	instr = p->fts_instr;
313 	p->fts_instr = FTS_NOINSTR;
314 
315 	/* Any type of file may be re-visited; re-stat and re-turn. */
316 	if (instr == FTS_AGAIN) {
317 		p->fts_info = fts_stat(sp, p, 0, -1);
318 		return (p);
319 	}
320 
321 	/*
322 	 * Following a symlink -- SLNONE test allows application to see
323 	 * SLNONE and recover.  If indirecting through a symlink, have
324 	 * keep a pointer to current location.  If unable to get that
325 	 * pointer, follow fails.
326 	 */
327 	if (instr == FTS_FOLLOW &&
328 	    (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
329 		p->fts_info = fts_stat(sp, p, 1, -1);
330 		if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
331 			if ((p->fts_symfd = _open(".", O_RDONLY | O_CLOEXEC,
332 			    0)) < 0) {
333 				p->fts_errno = errno;
334 				p->fts_info = FTS_ERR;
335 			} else
336 				p->fts_flags |= FTS_SYMFOLLOW;
337 		}
338 		return (p);
339 	}
340 
341 	/* Directory in pre-order. */
342 	if (p->fts_info == FTS_D) {
343 		/* If skipped or crossed mount point, do post-order visit. */
344 		if (instr == FTS_SKIP ||
345 		    (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
346 			if (p->fts_flags & FTS_SYMFOLLOW)
347 				(void)_close(p->fts_symfd);
348 			if (sp->fts_child) {
349 				fts_lfree(sp->fts_child);
350 				sp->fts_child = NULL;
351 			}
352 			p->fts_info = FTS_DP;
353 			return (p);
354 		}
355 
356 		/* Rebuild if only read the names and now traversing. */
357 		if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
358 			CLR(FTS_NAMEONLY);
359 			fts_lfree(sp->fts_child);
360 			sp->fts_child = NULL;
361 		}
362 
363 		/*
364 		 * Cd to the subdirectory.
365 		 *
366 		 * If have already read and now fail to chdir, whack the list
367 		 * to make the names come out right, and set the parent errno
368 		 * so the application will eventually get an error condition.
369 		 * Set the FTS_DONTCHDIR flag so that when we logically change
370 		 * directories back to the parent we don't do a chdir.
371 		 *
372 		 * If haven't read do so.  If the read fails, fts_build sets
373 		 * FTS_STOP or the fts_info field of the node.
374 		 */
375 		if (sp->fts_child != NULL) {
376 			if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
377 				p->fts_errno = errno;
378 				p->fts_flags |= FTS_DONTCHDIR;
379 				for (p = sp->fts_child; p != NULL;
380 				    p = p->fts_link)
381 					p->fts_accpath =
382 					    p->fts_parent->fts_accpath;
383 			}
384 		} else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
385 			if (ISSET(FTS_STOP))
386 				return (NULL);
387 			return (p);
388 		}
389 		p = sp->fts_child;
390 		sp->fts_child = NULL;
391 		goto name;
392 	}
393 
394 	/* Move to the next node on this level. */
395 next:	tmp = p;
396 	if ((p = p->fts_link) != NULL) {
397 		/*
398 		 * If reached the top, return to the original directory (or
399 		 * the root of the tree), and load the paths for the next root.
400 		 */
401 		if (p->fts_level == FTS_ROOTLEVEL) {
402 			if (FCHDIR(sp, sp->fts_rfd)) {
403 				SET(FTS_STOP);
404 				return (NULL);
405 			}
406 			free(tmp);
407 			fts_load(sp, p);
408 			return (sp->fts_cur = p);
409 		}
410 
411 		/*
412 		 * User may have called fts_set on the node.  If skipped,
413 		 * ignore.  If followed, get a file descriptor so we can
414 		 * get back if necessary.
415 		 */
416 		if (p->fts_instr == FTS_SKIP) {
417 			free(tmp);
418 			goto next;
419 		}
420 		if (p->fts_instr == FTS_FOLLOW) {
421 			p->fts_info = fts_stat(sp, p, 1, -1);
422 			if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
423 				if ((p->fts_symfd =
424 				    _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0) {
425 					p->fts_errno = errno;
426 					p->fts_info = FTS_ERR;
427 				} else
428 					p->fts_flags |= FTS_SYMFOLLOW;
429 			}
430 			p->fts_instr = FTS_NOINSTR;
431 		}
432 
433 		free(tmp);
434 
435 name:		t = sp->fts_path + NAPPEND(p->fts_parent);
436 		*t++ = '/';
437 		memmove(t, p->fts_name, p->fts_namelen + 1);
438 		return (sp->fts_cur = p);
439 	}
440 
441 	/* Move up to the parent node. */
442 	p = tmp->fts_parent;
443 
444 	if (p->fts_level == FTS_ROOTPARENTLEVEL) {
445 		/*
446 		 * Done; free everything up and set errno to 0 so the user
447 		 * can distinguish between error and EOF.
448 		 */
449 		free(tmp);
450 		free(p);
451 		errno = 0;
452 		return (sp->fts_cur = NULL);
453 	}
454 
455 	/* NUL terminate the pathname. */
456 	sp->fts_path[p->fts_pathlen] = '\0';
457 
458 	/*
459 	 * Return to the parent directory.  If at a root node or came through
460 	 * a symlink, go back through the file descriptor.  Otherwise, cd up
461 	 * one directory.
462 	 */
463 	if (p->fts_level == FTS_ROOTLEVEL) {
464 		if (FCHDIR(sp, sp->fts_rfd)) {
465 			SET(FTS_STOP);
466 			return (NULL);
467 		}
468 	} else if (p->fts_flags & FTS_SYMFOLLOW) {
469 		if (FCHDIR(sp, p->fts_symfd)) {
470 			saved_errno = errno;
471 			(void)_close(p->fts_symfd);
472 			errno = saved_errno;
473 			SET(FTS_STOP);
474 			return (NULL);
475 		}
476 		(void)_close(p->fts_symfd);
477 	} else if (!(p->fts_flags & FTS_DONTCHDIR) &&
478 	    fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
479 		SET(FTS_STOP);
480 		return (NULL);
481 	}
482 	free(tmp);
483 	p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
484 	return (sp->fts_cur = p);
485 }
486 
487 /*
488  * Fts_set takes the stream as an argument although it's not used in this
489  * implementation; it would be necessary if anyone wanted to add global
490  * semantics to fts using fts_set.  An error return is allowed for similar
491  * reasons.
492  */
493 /* ARGSUSED */
494 int
495 freebsd11_fts_set(FTS11 *sp, FTSENT11 *p, int instr)
496 {
497 	if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
498 	    instr != FTS_NOINSTR && instr != FTS_SKIP) {
499 		errno = EINVAL;
500 		return (1);
501 	}
502 	p->fts_instr = instr;
503 	return (0);
504 }
505 
506 FTSENT11 *
507 freebsd11_fts_children(FTS11 *sp, int instr)
508 {
509 	FTSENT11 *p;
510 	int fd, rc, serrno;
511 
512 	if (instr != 0 && instr != FTS_NAMEONLY) {
513 		errno = EINVAL;
514 		return (NULL);
515 	}
516 
517 	/* Set current node pointer. */
518 	p = sp->fts_cur;
519 
520 	/*
521 	 * Errno set to 0 so user can distinguish empty directory from
522 	 * an error.
523 	 */
524 	errno = 0;
525 
526 	/* Fatal errors stop here. */
527 	if (ISSET(FTS_STOP))
528 		return (NULL);
529 
530 	/* Return logical hierarchy of user's arguments. */
531 	if (p->fts_info == FTS_INIT)
532 		return (p->fts_link);
533 
534 	/*
535 	 * If not a directory being visited in pre-order, stop here.  Could
536 	 * allow FTS_DNR, assuming the user has fixed the problem, but the
537 	 * same effect is available with FTS_AGAIN.
538 	 */
539 	if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
540 		return (NULL);
541 
542 	/* Free up any previous child list. */
543 	if (sp->fts_child != NULL)
544 		fts_lfree(sp->fts_child);
545 
546 	if (instr == FTS_NAMEONLY) {
547 		SET(FTS_NAMEONLY);
548 		instr = BNAMES;
549 	} else
550 		instr = BCHILD;
551 
552 	/*
553 	 * If using chdir on a relative path and called BEFORE fts_read does
554 	 * its chdir to the root of a traversal, we can lose -- we need to
555 	 * chdir into the subdirectory, and we don't know where the current
556 	 * directory is, so we can't get back so that the upcoming chdir by
557 	 * fts_read will work.
558 	 */
559 	if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
560 	    ISSET(FTS_NOCHDIR))
561 		return (sp->fts_child = fts_build(sp, instr));
562 
563 	if ((fd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
564 		return (NULL);
565 	sp->fts_child = fts_build(sp, instr);
566 	serrno = (sp->fts_child == NULL) ? errno : 0;
567 	rc = fchdir(fd);
568 	if (rc < 0 && serrno == 0)
569 		serrno = errno;
570 	(void)_close(fd);
571 	errno = serrno;
572 	if (rc < 0)
573 		return (NULL);
574 	return (sp->fts_child);
575 }
576 
577 #ifndef freebsd11_fts_get_clientptr
578 #error "freebsd11_fts_get_clientptr not defined"
579 #endif
580 
581 void *
582 (freebsd11_fts_get_clientptr)(FTS11 *sp)
583 {
584 
585 	return (freebsd11_fts_get_clientptr(sp));
586 }
587 
588 #ifndef freebsd11_fts_get_stream
589 #error "freebsd11_fts_get_stream not defined"
590 #endif
591 
592 FTS11 *
593 (freebsd11_fts_get_stream)(FTSENT11 *p)
594 {
595 	return (freebsd11_fts_get_stream(p));
596 }
597 
598 void
599 freebsd11_fts_set_clientptr(FTS11 *sp, void *clientptr)
600 {
601 
602 	sp->fts_clientptr = clientptr;
603 }
604 
605 static struct freebsd11_dirent *
606 fts_safe_readdir(DIR *dirp, int *readdir_errno)
607 {
608 	struct freebsd11_dirent *ret;
609 
610 	errno = 0;
611 	if (!dirp)
612 		return (NULL);
613 	ret = freebsd11_readdir(dirp);
614 	*readdir_errno = errno;
615 	return (ret);
616 }
617 
618 /*
619  * This is the tricky part -- do not casually change *anything* in here.  The
620  * idea is to build the linked list of entries that are used by fts_children
621  * and fts_read.  There are lots of special cases.
622  *
623  * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
624  * set and it's a physical walk (so that symbolic links can't be directories),
625  * we can do things quickly.  First, if it's a 4.4BSD file system, the type
626  * of the file is in the directory entry.  Otherwise, we assume that the number
627  * of subdirectories in a node is equal to the number of links to the parent.
628  * The former skips all stat calls.  The latter skips stat calls in any leaf
629  * directories and for any files after the subdirectories in the directory have
630  * been found, cutting the stat calls by about 2/3.
631  */
632 static FTSENT11 *
633 fts_build(FTS11 *sp, int type)
634 {
635 	struct freebsd11_dirent *dp;
636 	FTSENT11 *p, *head;
637 	FTSENT11 *cur, *tail;
638 	DIR *dirp;
639 	void *oldaddr;
640 	char *cp;
641 	int cderrno, descend, oflag, saved_errno, nostat, doadjust,
642 	    readdir_errno;
643 	long level;
644 	long nlinks;	/* has to be signed because -1 is a magic value */
645 	size_t dnamlen, len, maxlen, nitems;
646 
647 	/* Set current node pointer. */
648 	cur = sp->fts_cur;
649 
650 	/*
651 	 * Open the directory for reading.  If this fails, we're done.
652 	 * If being called from fts_read, set the fts_info field.
653 	 */
654 #ifdef FTS_WHITEOUT
655 	if (ISSET(FTS_WHITEOUT))
656 		oflag = DTF_NODUP;
657 	else
658 		oflag = DTF_HIDEW | DTF_NODUP;
659 #else
660 #define __opendir2(path, flag) opendir(path)
661 #endif
662 	if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
663 		if (type == BREAD) {
664 			cur->fts_info = FTS_DNR;
665 			cur->fts_errno = errno;
666 		}
667 		return (NULL);
668 	}
669 
670 	/*
671 	 * Nlinks is the number of possible entries of type directory in the
672 	 * directory if we're cheating on stat calls, 0 if we're not doing
673 	 * any stat calls at all, -1 if we're doing stats on everything.
674 	 */
675 	if (type == BNAMES) {
676 		nlinks = 0;
677 		/* Be quiet about nostat, GCC. */
678 		nostat = 0;
679 	} else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL)) {
680 		if (fts_ufslinks(sp, cur))
681 			nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
682 		else
683 			nlinks = -1;
684 		nostat = 1;
685 	} else {
686 		nlinks = -1;
687 		nostat = 0;
688 	}
689 
690 #ifdef notdef
691 	(void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
692 	(void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
693 	    ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
694 #endif
695 	/*
696 	 * If we're going to need to stat anything or we want to descend
697 	 * and stay in the directory, chdir.  If this fails we keep going,
698 	 * but set a flag so we don't chdir after the post-order visit.
699 	 * We won't be able to stat anything, but we can still return the
700 	 * names themselves.  Note, that since fts_read won't be able to
701 	 * chdir into the directory, it will have to return different path
702 	 * names than before, i.e. "a/b" instead of "b".  Since the node
703 	 * has already been visited in pre-order, have to wait until the
704 	 * post-order visit to return the error.  There is a special case
705 	 * here, if there was nothing to stat then it's not an error to
706 	 * not be able to stat.  This is all fairly nasty.  If a program
707 	 * needed sorted entries or stat information, they had better be
708 	 * checking FTS_NS on the returned nodes.
709 	 */
710 	cderrno = 0;
711 	if (nlinks || type == BREAD) {
712 		if (fts_safe_changedir(sp, cur, _dirfd(dirp), NULL)) {
713 			if (nlinks && type == BREAD)
714 				cur->fts_errno = errno;
715 			cur->fts_flags |= FTS_DONTCHDIR;
716 			descend = 0;
717 			cderrno = errno;
718 		} else
719 			descend = 1;
720 	} else
721 		descend = 0;
722 
723 	/*
724 	 * Figure out the max file name length that can be stored in the
725 	 * current path -- the inner loop allocates more path as necessary.
726 	 * We really wouldn't have to do the maxlen calculations here, we
727 	 * could do them in fts_read before returning the path, but it's a
728 	 * lot easier here since the length is part of the dirent structure.
729 	 *
730 	 * If not changing directories set a pointer so that can just append
731 	 * each new name into the path.
732 	 */
733 	len = NAPPEND(cur);
734 	if (ISSET(FTS_NOCHDIR)) {
735 		cp = sp->fts_path + len;
736 		*cp++ = '/';
737 	} else {
738 		/* GCC, you're too verbose. */
739 		cp = NULL;
740 	}
741 	len++;
742 	maxlen = sp->fts_pathlen - len;
743 
744 	level = cur->fts_level + 1;
745 
746 	/* Read the directory, attaching each entry to the `link' pointer. */
747 	doadjust = 0;
748 	readdir_errno = 0;
749 	for (head = tail = NULL, nitems = 0;
750 	    (dp = fts_safe_readdir(dirp, &readdir_errno));) {
751 		dnamlen = dp->d_namlen;
752 		if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
753 			continue;
754 
755 		if ((p = fts_alloc(sp, dp->d_name, dnamlen)) == NULL)
756 			goto mem1;
757 		if (dnamlen >= maxlen) {	/* include space for NUL */
758 			oldaddr = sp->fts_path;
759 			if (fts_palloc(sp, dnamlen + len + 1)) {
760 				/*
761 				 * No more memory for path or structures.  Save
762 				 * errno, free up the current structure and the
763 				 * structures already allocated.
764 				 */
765 mem1:				saved_errno = errno;
766 				if (p)
767 					free(p);
768 				fts_lfree(head);
769 				(void)closedir(dirp);
770 				cur->fts_info = FTS_ERR;
771 				SET(FTS_STOP);
772 				errno = saved_errno;
773 				return (NULL);
774 			}
775 			/* Did realloc() change the pointer? */
776 			if (oldaddr != sp->fts_path) {
777 				doadjust = 1;
778 				if (ISSET(FTS_NOCHDIR))
779 					cp = sp->fts_path + len;
780 			}
781 			maxlen = sp->fts_pathlen - len;
782 		}
783 
784 		p->fts_level = level;
785 		p->fts_parent = sp->fts_cur;
786 		p->fts_pathlen = len + dnamlen;
787 
788 #ifdef FTS_WHITEOUT
789 		if (dp->d_type == DT_WHT)
790 			p->fts_flags |= FTS_ISW;
791 #endif
792 
793 		if (cderrno) {
794 			if (nlinks) {
795 				p->fts_info = FTS_NS;
796 				p->fts_errno = cderrno;
797 			} else
798 				p->fts_info = FTS_NSOK;
799 			p->fts_accpath = cur->fts_accpath;
800 		} else if (nlinks == 0
801 #ifdef DT_DIR
802 		    || (nostat &&
803 		    dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN)
804 #endif
805 		    ) {
806 			p->fts_accpath =
807 			    ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
808 			p->fts_info = FTS_NSOK;
809 		} else {
810 			/* Build a file name for fts_stat to stat. */
811 			if (ISSET(FTS_NOCHDIR)) {
812 				p->fts_accpath = p->fts_path;
813 				memmove(cp, p->fts_name, p->fts_namelen + 1);
814 				p->fts_info = fts_stat(sp, p, 0, _dirfd(dirp));
815 			} else {
816 				p->fts_accpath = p->fts_name;
817 				p->fts_info = fts_stat(sp, p, 0, -1);
818 			}
819 
820 			/* Decrement link count if applicable. */
821 			if (nlinks > 0 && (p->fts_info == FTS_D ||
822 			    p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
823 				--nlinks;
824 		}
825 
826 		/* We walk in directory order so "ls -f" doesn't get upset. */
827 		p->fts_link = NULL;
828 		if (head == NULL)
829 			head = tail = p;
830 		else {
831 			tail->fts_link = p;
832 			tail = p;
833 		}
834 		++nitems;
835 	}
836 
837 	if (readdir_errno) {
838 		cur->fts_errno = readdir_errno;
839 		/*
840 		 * If we've not read any items yet, treat
841 		 * the error as if we can't access the dir.
842 		 */
843 		cur->fts_info = nitems ? FTS_ERR : FTS_DNR;
844 	}
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 		sp->fts_path[cur->fts_pathlen] = '\0';
862 
863 	/*
864 	 * If descended after called from fts_children or after called from
865 	 * fts_read and nothing found, get back.  At the root level we use
866 	 * the saved fd; if one of fts_open()'s arguments is a relative path
867 	 * to an empty directory, we wind up here with no other way back.  If
868 	 * can't get back, we're done.
869 	 */
870 	if (descend && (type == BCHILD || !nitems) &&
871 	    (cur->fts_level == FTS_ROOTLEVEL ?
872 	    FCHDIR(sp, sp->fts_rfd) :
873 	    fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
874 		fts_lfree(head);
875 		cur->fts_info = FTS_ERR;
876 		SET(FTS_STOP);
877 		return (NULL);
878 	}
879 
880 	/* If didn't find anything, return NULL. */
881 	if (!nitems) {
882 		if (type == BREAD &&
883 		    cur->fts_info != FTS_DNR && cur->fts_info != FTS_ERR)
884 			cur->fts_info = FTS_DP;
885 		return (NULL);
886 	}
887 
888 	/* Sort the entries. */
889 	if (sp->fts_compar && nitems > 1)
890 		head = fts_sort(sp, head, nitems);
891 	return (head);
892 }
893 
894 static int
895 fts_stat(FTS11 *sp, FTSENT11 *p, int follow, int dfd)
896 {
897 	FTSENT11 *t;
898 	uint32_t dev;
899 	uint32_t ino;
900 	struct freebsd11_stat *sbp, sb;
901 	int saved_errno;
902 	const char *path;
903 
904 	if (dfd == -1)
905 		path = p->fts_accpath, dfd = AT_FDCWD;
906 	else
907 		path = p->fts_name;
908 
909 	/* If user needs stat info, stat buffer already allocated. */
910 	sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
911 
912 #ifdef FTS_WHITEOUT
913 	/* Check for whiteout. */
914 	if (p->fts_flags & FTS_ISW) {
915 		if (sbp != &sb) {
916 			memset(sbp, '\0', sizeof(*sbp));
917 			sbp->st_mode = S_IFWHT;
918 		}
919 		return (FTS_W);
920 	}
921 #endif
922 
923 	/*
924 	 * If doing a logical walk, or application requested FTS_FOLLOW, do
925 	 * a stat(2).  If that fails, check for a non-existent symlink.  If
926 	 * fail, set the errno from the stat call.
927 	 */
928 	if (ISSET(FTS_LOGICAL) || follow) {
929 		if (freebsd11_fstatat(dfd, path, sbp, 0)) {
930 			saved_errno = errno;
931 			if (freebsd11_fstatat(dfd, path, sbp,
932 			    AT_SYMLINK_NOFOLLOW)) {
933 				p->fts_errno = saved_errno;
934 				goto err;
935 			}
936 			errno = 0;
937 			if (S_ISLNK(sbp->st_mode))
938 				return (FTS_SLNONE);
939 		}
940 	} else if (freebsd11_fstatat(dfd, path, sbp, AT_SYMLINK_NOFOLLOW)) {
941 		p->fts_errno = errno;
942 err:		memset(sbp, 0, sizeof(*sbp));
943 		return (FTS_NS);
944 	}
945 
946 	if (S_ISDIR(sbp->st_mode)) {
947 		/*
948 		 * Set the device/inode.  Used to find cycles and check for
949 		 * crossing mount points.  Also remember the link count, used
950 		 * in fts_build to limit the number of stat calls.  It is
951 		 * understood that these fields are only referenced if fts_info
952 		 * is set to FTS_D.
953 		 */
954 		dev = p->fts_dev = sbp->st_dev;
955 		ino = p->fts_ino = sbp->st_ino;
956 		p->fts_nlink = sbp->st_nlink;
957 
958 		if (ISDOT(p->fts_name))
959 			return (FTS_DOT);
960 
961 		/*
962 		 * Cycle detection is done by brute force when the directory
963 		 * is first encountered.  If the tree gets deep enough or the
964 		 * number of symbolic links to directories is high enough,
965 		 * something faster might be worthwhile.
966 		 */
967 		for (t = p->fts_parent;
968 		    t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
969 			if (ino == t->fts_ino && dev == t->fts_dev) {
970 				p->fts_cycle = t;
971 				return (FTS_DC);
972 			}
973 		return (FTS_D);
974 	}
975 	if (S_ISLNK(sbp->st_mode))
976 		return (FTS_SL);
977 	if (S_ISREG(sbp->st_mode))
978 		return (FTS_F);
979 	return (FTS_DEFAULT);
980 }
981 
982 /*
983  * The comparison function takes pointers to pointers to FTSENT structures.
984  * Qsort wants a comparison function that takes pointers to void.
985  * (Both with appropriate levels of const-poisoning, of course!)
986  * Use a trampoline function to deal with the difference.
987  */
988 static int
989 fts_compar(const void *a, const void *b)
990 {
991 	FTS11 *parent;
992 
993 	parent = (*(const FTSENT11 * const *)a)->fts_fts;
994 	return (*parent->fts_compar)(a, b);
995 }
996 
997 static FTSENT11 *
998 fts_sort(FTS11 *sp, FTSENT11 *head, size_t nitems)
999 {
1000 	FTSENT11 **ap, *p;
1001 
1002 	/*
1003 	 * Construct an array of pointers to the structures and call qsort(3).
1004 	 * Reassemble the array in the order returned by qsort.  If unable to
1005 	 * sort for memory reasons, return the directory entries in their
1006 	 * current order.  Allocate enough space for the current needs plus
1007 	 * 40 so don't realloc one entry at a time.
1008 	 */
1009 	if (nitems > sp->fts_nitems) {
1010 		sp->fts_nitems = nitems + 40;
1011 		if ((sp->fts_array = reallocf(sp->fts_array,
1012 		    sp->fts_nitems * sizeof(FTSENT11 *))) == NULL) {
1013 			sp->fts_nitems = 0;
1014 			return (head);
1015 		}
1016 	}
1017 	for (ap = sp->fts_array, p = head; p; p = p->fts_link)
1018 		*ap++ = p;
1019 	qsort(sp->fts_array, nitems, sizeof(FTSENT11 *), fts_compar);
1020 	for (head = *(ap = sp->fts_array); --nitems; ++ap)
1021 		ap[0]->fts_link = ap[1];
1022 	ap[0]->fts_link = NULL;
1023 	return (head);
1024 }
1025 
1026 static FTSENT11 *
1027 fts_alloc(FTS11 *sp, char *name, size_t namelen)
1028 {
1029 	FTSENT11 *p;
1030 	size_t len;
1031 
1032 	struct ftsent11_withstat {
1033 		FTSENT11	ent;
1034 		struct	freebsd11_stat statbuf;
1035 	};
1036 
1037 	/*
1038 	 * The file name is a variable length array and no stat structure is
1039 	 * necessary if the user has set the nostat bit.  Allocate the FTSENT
1040 	 * structure, the file name and the stat structure in one chunk, but
1041 	 * be careful that the stat structure is reasonably aligned.
1042 	 */
1043 	if (ISSET(FTS_NOSTAT))
1044 		len = sizeof(FTSENT11) + namelen + 1;
1045 	else
1046 		len = sizeof(struct ftsent11_withstat) + namelen + 1;
1047 
1048 	if ((p = malloc(len)) == NULL)
1049 		return (NULL);
1050 
1051 	if (ISSET(FTS_NOSTAT)) {
1052 		p->fts_name = (char *)(p + 1);
1053 		p->fts_statp = NULL;
1054 	} else {
1055 		p->fts_name = (char *)((struct ftsent11_withstat *)p + 1);
1056 		p->fts_statp = &((struct ftsent11_withstat *)p)->statbuf;
1057 	}
1058 
1059 	/* Copy the name and guarantee NUL termination. */
1060 	memcpy(p->fts_name, name, namelen);
1061 	p->fts_name[namelen] = '\0';
1062 	p->fts_namelen = namelen;
1063 	p->fts_path = sp->fts_path;
1064 	p->fts_errno = 0;
1065 	p->fts_flags = 0;
1066 	p->fts_instr = FTS_NOINSTR;
1067 	p->fts_number = 0;
1068 	p->fts_pointer = NULL;
1069 	p->fts_fts = sp;
1070 	return (p);
1071 }
1072 
1073 static void
1074 fts_lfree(FTSENT11 *head)
1075 {
1076 	FTSENT11 *p;
1077 
1078 	/* Free a linked list of structures. */
1079 	while ((p = head)) {
1080 		head = head->fts_link;
1081 		free(p);
1082 	}
1083 }
1084 
1085 /*
1086  * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
1087  * Most systems will allow creation of paths much longer than MAXPATHLEN, even
1088  * though the kernel won't resolve them.  Add the size (not just what's needed)
1089  * plus 256 bytes so don't realloc the path 2 bytes at a time.
1090  */
1091 static int
1092 fts_palloc(FTS11 *sp, size_t more)
1093 {
1094 
1095 	sp->fts_pathlen += more + 256;
1096 	sp->fts_path = reallocf(sp->fts_path, sp->fts_pathlen);
1097 	return (sp->fts_path == NULL);
1098 }
1099 
1100 /*
1101  * When the path is realloc'd, have to fix all of the pointers in structures
1102  * already returned.
1103  */
1104 static void
1105 fts_padjust(FTS11 *sp, FTSENT11 *head)
1106 {
1107 	FTSENT11 *p;
1108 	char *addr = sp->fts_path;
1109 
1110 #define	ADJUST(p) do {							\
1111 	if ((p)->fts_accpath != (p)->fts_name) {			\
1112 		(p)->fts_accpath =					\
1113 		    (char *)addr + ((p)->fts_accpath - (p)->fts_path);	\
1114 	}								\
1115 	(p)->fts_path = addr;						\
1116 } while (0)
1117 	/* Adjust the current set of children. */
1118 	for (p = sp->fts_child; p; p = p->fts_link)
1119 		ADJUST(p);
1120 
1121 	/* Adjust the rest of the tree, including the current level. */
1122 	for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
1123 		ADJUST(p);
1124 		p = p->fts_link ? p->fts_link : p->fts_parent;
1125 	}
1126 }
1127 
1128 static size_t
1129 fts_maxarglen(char * const *argv)
1130 {
1131 	size_t len, max;
1132 
1133 	for (max = 0; *argv; ++argv)
1134 		if ((len = strlen(*argv)) > max)
1135 			max = len;
1136 	return (max + 1);
1137 }
1138 
1139 /*
1140  * Change to dir specified by fd or p->fts_accpath without getting
1141  * tricked by someone changing the world out from underneath us.
1142  * Assumes p->fts_dev and p->fts_ino are filled in.
1143  */
1144 static int
1145 fts_safe_changedir(FTS11 *sp, FTSENT11 *p, int fd, char *path)
1146 {
1147 	int ret, oerrno, newfd;
1148 	struct freebsd11_stat sb;
1149 
1150 	newfd = fd;
1151 	if (ISSET(FTS_NOCHDIR))
1152 		return (0);
1153 	if (fd < 0 && (newfd = _open(path, O_RDONLY | O_DIRECTORY |
1154 	    O_CLOEXEC, 0)) < 0)
1155 		return (-1);
1156 	if (freebsd11_fstat(newfd, &sb)) {
1157 		ret = -1;
1158 		goto bail;
1159 	}
1160 	if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
1161 		errno = ENOENT;		/* disinformation */
1162 		ret = -1;
1163 		goto bail;
1164 	}
1165 	ret = fchdir(newfd);
1166 bail:
1167 	oerrno = errno;
1168 	if (fd < 0)
1169 		(void)_close(newfd);
1170 	errno = oerrno;
1171 	return (ret);
1172 }
1173 
1174 /*
1175  * Check if the filesystem for "ent" has UFS-style links.
1176  */
1177 static int
1178 fts_ufslinks(FTS11 *sp, const FTSENT11 *ent)
1179 {
1180 	struct _fts_private11 *priv;
1181 	const char **cpp;
1182 
1183 	priv = (struct _fts_private11 *)sp;
1184 	/*
1185 	 * If this node's device is different from the previous, grab
1186 	 * the filesystem information, and decide on the reliability
1187 	 * of the link information from this filesystem for stat(2)
1188 	 * avoidance.
1189 	 */
1190 	if (priv->ftsp_dev != ent->fts_dev) {
1191 		if (freebsd11_statfs(ent->fts_path, &priv->ftsp_statfs) != -1) {
1192 			priv->ftsp_dev = ent->fts_dev;
1193 			priv->ftsp_linksreliable = 0;
1194 			for (cpp = ufslike_filesystems; *cpp; cpp++) {
1195 				if (strcmp(priv->ftsp_statfs.f_fstypename,
1196 				    *cpp) == 0) {
1197 					priv->ftsp_linksreliable = 1;
1198 					break;
1199 				}
1200 			}
1201 		} else {
1202 			priv->ftsp_linksreliable = 0;
1203 		}
1204 	}
1205 	return (priv->ftsp_linksreliable);
1206 }
1207 
1208 __sym_compat(fts_open, freebsd11_fts_open, FBSD_1.1);
1209 __sym_compat(fts_close, freebsd11_fts_close, FBSD_1.1);
1210 __sym_compat(fts_read, freebsd11_fts_read, FBSD_1.1);
1211 __sym_compat(fts_set, freebsd11_fts_set, FBSD_1.1);
1212 __sym_compat(fts_children, freebsd11_fts_children, FBSD_1.1);
1213 __sym_compat(fts_get_clientptr, freebsd11_fts_get_clientptr, FBSD_1.1);
1214 __sym_compat(fts_get_stream, freebsd11_fts_get_stream, FBSD_1.1);
1215 __sym_compat(fts_set_clientptr, freebsd11_fts_set_clientptr, FBSD_1.1);
1216