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 * 4. 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)
34static 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: head/lib/libc/gen/fts.c 199844 2009-11-26 19:11:44Z jh $");
40
41#include "namespace.h"
42#include <sys/param.h>
43#include <sys/mount.h>
44#include <sys/stat.h>
45
46#include <dirent.h>
47#include <errno.h>
48#include <fcntl.h>
49#include <fts.h>
50#include <stdlib.h>
51#include <string.h>
52#include <unistd.h>
53#include "un-namespace.h"
54
55static FTSENT *fts_alloc(FTS *, char *, size_t);
56static FTSENT *fts_build(FTS *, int);
57static void fts_lfree(FTSENT *);
58static void fts_load(FTS *, FTSENT *);
59static size_t fts_maxarglen(char * const *);
60static void fts_padjust(FTS *, FTSENT *);
61static int fts_palloc(FTS *, size_t);
62static FTSENT *fts_sort(FTS *, FTSENT *, size_t);
63static int fts_stat(FTS *, FTSENT *, int);
64static int fts_safe_changedir(FTS *, FTSENT *, int, char *);
65static int fts_ufslinks(FTS *, const FTSENT *);
66
67#define ISDOT(a) (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
68
69#define CLR(opt) (sp->fts_options &= ~(opt))
70#define ISSET(opt) (sp->fts_options & (opt))
71#define SET(opt) (sp->fts_options |= (opt))
72
73#define FCHDIR(sp, fd) (!ISSET(FTS_NOCHDIR) && fchdir(fd))
74
75/* fts_build flags */
76#define BCHILD 1 /* fts_children */
77#define BNAMES 2 /* fts_children, names only */
78#define BREAD 3 /* fts_read */
79
80/*
81 * Internal representation of an FTS, including extra implementation
82 * details. The FTS returned from fts_open points to this structure's
83 * ftsp_fts member (and can be cast to an _fts_private as required)
84 */
85struct _fts_private {
86 FTS ftsp_fts;
87 struct statfs ftsp_statfs;
88 dev_t ftsp_dev;
89 int ftsp_linksreliable;
90};
91
92/*
93 * The "FTS_NOSTAT" option can avoid a lot of calls to stat(2) if it
94 * knows that a directory could not possibly have subdirectories. This
95 * is decided by looking at the link count: a subdirectory would
96 * increment its parent's link count by virtue of its own ".." entry.
97 * This assumption only holds for UFS-like filesystems that implement
98 * links and directories this way, so we must punt for others.
99 */
100
101static const char *ufslike_filesystems[] = {
102 "ufs",
103 "nfs",
104 "nfs4",
105 "ext2fs",
106 0
107};
108
109FTS *
110fts_open(argv, options, compar)
111 char * const *argv;
112 int options;
113 int (*compar)(const FTSENT * const *, const FTSENT * const *);
114{
115 struct _fts_private *priv;
116 FTS *sp;
117 FTSENT *p, *root;
118 FTSENT *parent, *tmp;
119 size_t len, nitems;
120
121 /* Options check. */
122 if (options & ~FTS_OPTIONMASK) {
123 errno = EINVAL;
124 return (NULL);
125 }
126
127 /* fts_open() requires at least one path */
128 if (*argv == NULL) {
129 errno = EINVAL;
130 return (NULL);
131 }
132
133 /* Allocate/initialize the stream. */
134 if ((priv = malloc(sizeof(*priv))) == NULL)
135 return (NULL);
136 memset(priv, 0, sizeof(*priv));
137 sp = &priv->ftsp_fts;
138 sp->fts_compar = compar;
139 sp->fts_options = options;
140
141 /* Shush, GCC. */
142 tmp = NULL;
143
144 /* Logical walks turn on NOCHDIR; symbolic links are too hard. */
145 if (ISSET(FTS_LOGICAL))
146 SET(FTS_NOCHDIR);
147
148 /*
149 * Start out with 1K of path space, and enough, in any case,
150 * to hold the user's paths.
151 */
152 if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
153 goto mem1;
154
155 /* Allocate/initialize root's parent. */
156 if ((parent = fts_alloc(sp, "", 0)) == NULL)
157 goto mem2;
158 parent->fts_level = FTS_ROOTPARENTLEVEL;
159
160 /* Allocate/initialize root(s). */
161 for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
162 /* Don't allow zero-length paths. */
163 if ((len = strlen(*argv)) == 0) {
164 errno = ENOENT;
165 goto mem3;
166 }
167
168 p = fts_alloc(sp, *argv, len);
169 p->fts_level = FTS_ROOTLEVEL;
170 p->fts_parent = parent;
171 p->fts_accpath = p->fts_name;
172 p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW));
173
174 /* Command-line "." and ".." are real directories. */
175 if (p->fts_info == FTS_DOT)
176 p->fts_info = FTS_D;
177
178 /*
179 * If comparison routine supplied, traverse in sorted
180 * order; otherwise traverse in the order specified.
181 */
182 if (compar) {
183 p->fts_link = root;
184 root = p;
185 } else {
186 p->fts_link = NULL;
187 if (root == NULL)
188 tmp = root = p;
189 else {
190 tmp->fts_link = p;
191 tmp = p;
192 }
193 }
194 }
195 if (compar && nitems > 1)
196 root = fts_sort(sp, root, nitems);
197
198 /*
199 * Allocate a dummy pointer and make fts_read think that we've just
200 * finished the node before the root(s); set p->fts_info to FTS_INIT
201 * so that everything about the "current" node is ignored.
202 */
203 if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
204 goto mem3;
205 sp->fts_cur->fts_link = root;
206 sp->fts_cur->fts_info = FTS_INIT;
207
208 /*
209 * If using chdir(2), grab a file descriptor pointing to dot to ensure
210 * that we can get back here; this could be avoided for some paths,
211 * but almost certainly not worth the effort. Slashes, symbolic links,
212 * and ".." are all fairly nasty problems. Note, if we can't get the
213 * descriptor we run anyway, just more slowly.
214 */
215 if (!ISSET(FTS_NOCHDIR) && (sp->fts_rfd = _open(".", O_RDONLY, 0)) < 0)
216 SET(FTS_NOCHDIR);
217
218 return (sp);
219
220mem3: fts_lfree(root);
221 free(parent);
222mem2: free(sp->fts_path);
223mem1: free(sp);
224 return (NULL);
225}
226
227static void
228fts_load(sp, p)
229 FTS *sp;
230 FTSENT *p;
231{
232 size_t len;
233 char *cp;
234
235 /*
236 * Load the stream structure for the next traversal. Since we don't
237 * actually enter the directory until after the preorder visit, set
238 * the fts_accpath field specially so the chdir gets done to the right
239 * place and the user can access the first node. From fts_open it's
240 * known that the path will fit.
241 */
242 len = p->fts_pathlen = p->fts_namelen;
243 memmove(sp->fts_path, p->fts_name, len + 1);
244 if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
245 len = strlen(++cp);
246 memmove(p->fts_name, cp, len + 1);
247 p->fts_namelen = len;
248 }
249 p->fts_accpath = p->fts_path = sp->fts_path;
250 sp->fts_dev = p->fts_dev;
251}
252
253int
254fts_close(sp)
255 FTS *sp;
256{
257 FTSENT *freep, *p;
258 int saved_errno;
259
260 /*
261 * This still works if we haven't read anything -- the dummy structure
262 * points to the root list, so we step through to the end of the root
263 * list which has a valid parent pointer.
264 */
265 if (sp->fts_cur) {
266 for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
267 freep = p;
268 p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
269 free(freep);
270 }
271 free(p);
272 }
273
274 /* Free up child linked list, sort array, path buffer. */
275 if (sp->fts_child)
276 fts_lfree(sp->fts_child);
277 if (sp->fts_array)
278 free(sp->fts_array);
279 free(sp->fts_path);
280
281 /* Return to original directory, save errno if necessary. */
282 if (!ISSET(FTS_NOCHDIR)) {
283 saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
284 (void)_close(sp->fts_rfd);
285
286 /* Set errno and return. */
287 if (saved_errno != 0) {
288 /* Free up the stream pointer. */
289 free(sp);
290 errno = saved_errno;
291 return (-1);
292 }
293 }
294
295 /* Free up the stream pointer. */
296 free(sp);
297 return (0);
298}
299
300/*
301 * Special case of "/" at the end of the path so that slashes aren't
302 * appended which would cause paths to be written as "....//foo".
303 */
304#define NAPPEND(p) \
305 (p->fts_path[p->fts_pathlen - 1] == '/' \
306 ? p->fts_pathlen - 1 : p->fts_pathlen)
307
308FTSENT *
309fts_read(sp)
310 FTS *sp;
311{
312 FTSENT *p, *tmp;
313 int instr;
314 char *t;
315 int saved_errno;
316
317 /* If finished or unrecoverable error, return NULL. */
318 if (sp->fts_cur == NULL || ISSET(FTS_STOP))
319 return (NULL);
320
321 /* Set current node pointer. */
322 p = sp->fts_cur;
323
324 /* Save and zero out user instructions. */
325 instr = p->fts_instr;
326 p->fts_instr = FTS_NOINSTR;
327
328 /* Any type of file may be re-visited; re-stat and re-turn. */
329 if (instr == FTS_AGAIN) {
330 p->fts_info = fts_stat(sp, p, 0);
331 return (p);
332 }
333
334 /*
335 * Following a symlink -- SLNONE test allows application to see
336 * SLNONE and recover. If indirecting through a symlink, have
337 * keep a pointer to current location. If unable to get that
338 * pointer, follow fails.
339 */
340 if (instr == FTS_FOLLOW &&
341 (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
342 p->fts_info = fts_stat(sp, p, 1);
343 if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
344 if ((p->fts_symfd = _open(".", O_RDONLY, 0)) < 0) {
345 p->fts_errno = errno;
346 p->fts_info = FTS_ERR;
347 } else
348 p->fts_flags |= FTS_SYMFOLLOW;
349 }
350 return (p);
351 }
352
353 /* Directory in pre-order. */
354 if (p->fts_info == FTS_D) {
355 /* If skipped or crossed mount point, do post-order visit. */
356 if (instr == FTS_SKIP ||
357 (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
358 if (p->fts_flags & FTS_SYMFOLLOW)
359 (void)_close(p->fts_symfd);
360 if (sp->fts_child) {
361 fts_lfree(sp->fts_child);
362 sp->fts_child = NULL;
363 }
364 p->fts_info = FTS_DP;
365 return (p);
366 }
367
368 /* Rebuild if only read the names and now traversing. */
369 if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
370 CLR(FTS_NAMEONLY);
371 fts_lfree(sp->fts_child);
372 sp->fts_child = NULL;
373 }
374
375 /*
376 * Cd to the subdirectory.
377 *
378 * If have already read and now fail to chdir, whack the list
379 * to make the names come out right, and set the parent errno
380 * so the application will eventually get an error condition.
381 * Set the FTS_DONTCHDIR flag so that when we logically change
382 * directories back to the parent we don't do a chdir.
383 *
384 * If haven't read do so. If the read fails, fts_build sets
385 * FTS_STOP or the fts_info field of the node.
386 */
387 if (sp->fts_child != NULL) {
388 if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
389 p->fts_errno = errno;
390 p->fts_flags |= FTS_DONTCHDIR;
391 for (p = sp->fts_child; p != NULL;
392 p = p->fts_link)
393 p->fts_accpath =
394 p->fts_parent->fts_accpath;
395 }
396 } else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
397 if (ISSET(FTS_STOP))
398 return (NULL);
399 return (p);
400 }
401 p = sp->fts_child;
402 sp->fts_child = NULL;
403 goto name;
404 }
405
406 /* Move to the next node on this level. */
407next: tmp = p;
408 if ((p = p->fts_link) != NULL) {
409 free(tmp);
410
411 /*
412 * If reached the top, return to the original directory (or
413 * the root of the tree), and load the paths for the next root.
414 */
415 if (p->fts_level == FTS_ROOTLEVEL) {
416 if (FCHDIR(sp, sp->fts_rfd)) {
417 SET(FTS_STOP);
418 return (NULL);
419 }
420 fts_load(sp, p);
421 return (sp->fts_cur = p);
422 }
423
424 /*
425 * User may have called fts_set on the node. If skipped,
426 * ignore. If followed, get a file descriptor so we can
427 * get back if necessary.
428 */
429 if (p->fts_instr == FTS_SKIP)
430 goto next;
431 if (p->fts_instr == FTS_FOLLOW) {
432 p->fts_info = fts_stat(sp, p, 1);
433 if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
434 if ((p->fts_symfd =
435 _open(".", O_RDONLY, 0)) < 0) {
436 p->fts_errno = errno;
437 p->fts_info = FTS_ERR;
438 } else
439 p->fts_flags |= FTS_SYMFOLLOW;
440 }
441 p->fts_instr = FTS_NOINSTR;
442 }
443
444name: t = sp->fts_path + NAPPEND(p->fts_parent);
445 *t++ = '/';
446 memmove(t, p->fts_name, p->fts_namelen + 1);
447 return (sp->fts_cur = p);
448 }
449
450 /* Move up to the parent node. */
451 p = tmp->fts_parent;
452 free(tmp);
453
454 if (p->fts_level == FTS_ROOTPARENTLEVEL) {
455 /*
456 * Done; free everything up and set errno to 0 so the user
457 * can distinguish between error and EOF.
458 */
459 free(p);
460 errno = 0;
461 return (sp->fts_cur = NULL);
462 }
463
464 /* NUL terminate the pathname. */
465 sp->fts_path[p->fts_pathlen] = '\0';
466
467 /*
468 * Return to the parent directory. If at a root node or came through
469 * a symlink, go back through the file descriptor. Otherwise, cd up
470 * one directory.
471 */
472 if (p->fts_level == FTS_ROOTLEVEL) {
473 if (FCHDIR(sp, sp->fts_rfd)) {
474 SET(FTS_STOP);
475 return (NULL);
476 }
477 } else if (p->fts_flags & FTS_SYMFOLLOW) {
478 if (FCHDIR(sp, p->fts_symfd)) {
479 saved_errno = errno;
480 (void)_close(p->fts_symfd);
481 errno = saved_errno;
482 SET(FTS_STOP);
483 return (NULL);
484 }
485 (void)_close(p->fts_symfd);
486 } else if (!(p->fts_flags & FTS_DONTCHDIR) &&
487 fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
488 SET(FTS_STOP);
489 return (NULL);
490 }
491 p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
492 return (sp->fts_cur = p);
493}
494
495/*
496 * Fts_set takes the stream as an argument although it's not used in this
497 * implementation; it would be necessary if anyone wanted to add global
498 * semantics to fts using fts_set. An error return is allowed for similar
499 * reasons.
500 */
501/* ARGSUSED */
502int
503fts_set(sp, p, instr)
504 FTS *sp;
505 FTSENT *p;
506 int instr;
507{
508 if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
509 instr != FTS_NOINSTR && instr != FTS_SKIP) {
510 errno = EINVAL;
511 return (1);
512 }
513 p->fts_instr = instr;
514 return (0);
515}
516
517FTSENT *
518fts_children(sp, instr)
519 FTS *sp;
520 int instr;
521{
522 FTSENT *p;
523 int fd;
524
525 if (instr != 0 && instr != FTS_NAMEONLY) {
526 errno = EINVAL;
527 return (NULL);
528 }
529
530 /* Set current node pointer. */
531 p = sp->fts_cur;
532
533 /*
534 * Errno set to 0 so user can distinguish empty directory from
535 * an error.
536 */
537 errno = 0;
538
539 /* Fatal errors stop here. */
540 if (ISSET(FTS_STOP))
541 return (NULL);
542
543 /* Return logical hierarchy of user's arguments. */
544 if (p->fts_info == FTS_INIT)
545 return (p->fts_link);
546
547 /*
548 * If not a directory being visited in pre-order, stop here. Could
549 * allow FTS_DNR, assuming the user has fixed the problem, but the
550 * same effect is available with FTS_AGAIN.
551 */
552 if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
553 return (NULL);
554
555 /* Free up any previous child list. */
556 if (sp->fts_child != NULL)
557 fts_lfree(sp->fts_child);
558
559 if (instr == FTS_NAMEONLY) {
560 SET(FTS_NAMEONLY);
561 instr = BNAMES;
562 } else
563 instr = BCHILD;
564
565 /*
566 * If using chdir on a relative path and called BEFORE fts_read does
567 * its chdir to the root of a traversal, we can lose -- we need to
568 * chdir into the subdirectory, and we don't know where the current
569 * directory is, so we can't get back so that the upcoming chdir by
570 * fts_read will work.
571 */
572 if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
573 ISSET(FTS_NOCHDIR))
574 return (sp->fts_child = fts_build(sp, instr));
575
576 if ((fd = _open(".", O_RDONLY, 0)) < 0)
577 return (NULL);
578 sp->fts_child = fts_build(sp, instr);
579 if (fchdir(fd)) {
580 (void)_close(fd);
581 return (NULL);
582 }
583 (void)_close(fd);
584 return (sp->fts_child);
585}
586
587#ifndef fts_get_clientptr
588#error "fts_get_clientptr not defined"
589#endif
590
591void *
592(fts_get_clientptr)(FTS *sp)
593{
594
595 return (fts_get_clientptr(sp));
596}
597
598#ifndef fts_get_stream
599#error "fts_get_stream not defined"
600#endif
601
602FTS *
603(fts_get_stream)(FTSENT *p)
604{
605 return (fts_get_stream(p));
606}
607
608void
609fts_set_clientptr(FTS *sp, void *clientptr)
610{
611
612 sp->fts_clientptr = clientptr;
613}
614
615/*
616 * This is the tricky part -- do not casually change *anything* in here. The
617 * idea is to build the linked list of entries that are used by fts_children
618 * and fts_read. There are lots of special cases.
619 *
620 * The real slowdown in walking the tree is the stat calls. If FTS_NOSTAT is
621 * set and it's a physical walk (so that symbolic links can't be directories),
622 * we can do things quickly. First, if it's a 4.4BSD file system, the type
623 * of the file is in the directory entry. Otherwise, we assume that the number
624 * of subdirectories in a node is equal to the number of links to the parent.
625 * The former skips all stat calls. The latter skips stat calls in any leaf
626 * directories and for any files after the subdirectories in the directory have
627 * been found, cutting the stat calls by about 2/3.
628 */
629static FTSENT *
630fts_build(sp, type)
631 FTS *sp;
632 int type;
633{
634 struct dirent *dp;
635 FTSENT *p, *head;
636 FTSENT *cur, *tail;
637 DIR *dirp;
638 void *oldaddr;
639 char *cp;
640 int cderrno, descend, oflag, saved_errno, nostat, doadjust;
641 long level;
642 long nlinks; /* has to be signed because -1 is a magic value */
643 size_t dnamlen, len, maxlen, nitems;
644
645 /* Set current node pointer. */
646 cur = sp->fts_cur;
647
648 /*
649 * Open the directory for reading. If this fails, we're done.
650 * If being called from fts_read, set the fts_info field.
651 */
652#ifdef FTS_WHITEOUT
653 if (ISSET(FTS_WHITEOUT))
654 oflag = DTF_NODUP | DTF_REWIND;
655 else
656 oflag = DTF_HIDEW | DTF_NODUP | DTF_REWIND;
657#else
658#define __opendir2(path, flag) opendir(path)
659#endif
660 if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
661 if (type == BREAD) {
662 cur->fts_info = FTS_DNR;
663 cur->fts_errno = errno;
664 }
665 return (NULL);
666 }
667
668 /*
669 * Nlinks is the number of possible entries of type directory in the
670 * directory if we're cheating on stat calls, 0 if we're not doing
671 * any stat calls at all, -1 if we're doing stats on everything.
672 */
673 if (type == BNAMES) {
674 nlinks = 0;
675 /* Be quiet about nostat, GCC. */
676 nostat = 0;
677 } else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL)) {
678 if (fts_ufslinks(sp, cur))
679 nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
680 else
681 nlinks = -1;
682 nostat = 1;
683 } else {
684 nlinks = -1;
685 nostat = 0;
686 }
687
688#ifdef notdef
689 (void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
690 (void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
691 ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
692#endif
693 /*
694 * If we're going to need to stat anything or we want to descend
695 * and stay in the directory, chdir. If this fails we keep going,
696 * but set a flag so we don't chdir after the post-order visit.
697 * We won't be able to stat anything, but we can still return the
698 * names themselves. Note, that since fts_read won't be able to
699 * chdir into the directory, it will have to return different path
700 * names than before, i.e. "a/b" instead of "b". Since the node
701 * has already been visited in pre-order, have to wait until the
702 * post-order visit to return the error. There is a special case
703 * here, if there was nothing to stat then it's not an error to
704 * not be able to stat. This is all fairly nasty. If a program
705 * needed sorted entries or stat information, they had better be
706 * checking FTS_NS on the returned nodes.
707 */
708 cderrno = 0;
709 if (nlinks || type == BREAD) {
710 if (fts_safe_changedir(sp, cur, dirfd(dirp), NULL)) {
711 if (nlinks && type == BREAD)
712 cur->fts_errno = errno;
713 cur->fts_flags |= FTS_DONTCHDIR;
714 descend = 0;
715 cderrno = errno;
716 } else
717 descend = 1;
718 } else
719 descend = 0;
720
721 /*
722 * Figure out the max file name length that can be stored in the
723 * current path -- the inner loop allocates more path as necessary.
724 * We really wouldn't have to do the maxlen calculations here, we
725 * could do them in fts_read before returning the path, but it's a
726 * lot easier here since the length is part of the dirent structure.
727 *
728 * If not changing directories set a pointer so that can just append
729 * each new name into the path.
730 */
731 len = NAPPEND(cur);
732 if (ISSET(FTS_NOCHDIR)) {
733 cp = sp->fts_path + len;
734 *cp++ = '/';
735 } else {
736 /* GCC, you're too verbose. */
737 cp = NULL;
738 }
739 len++;
740 maxlen = sp->fts_pathlen - len;
741
742 level = cur->fts_level + 1;
743
744 /* Read the directory, attaching each entry to the `link' pointer. */
745 doadjust = 0;
746 for (head = tail = NULL, nitems = 0; dirp && (dp = 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, 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 */
761mem1: 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 p->fts_level = level;
781 p->fts_parent = sp->fts_cur;
782 p->fts_pathlen = len + dnamlen;
783
784#ifdef FTS_WHITEOUT
785 if (dp->d_type == DT_WHT)
786 p->fts_flags |= FTS_ISW;
787#endif
788
789 if (cderrno) {
790 if (nlinks) {
791 p->fts_info = FTS_NS;
792 p->fts_errno = cderrno;
793 } else
794 p->fts_info = FTS_NSOK;
795 p->fts_accpath = cur->fts_accpath;
796 } else if (nlinks == 0
797#ifdef DT_DIR
798 || (nostat &&
799 dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN)
800#endif
801 ) {
802 p->fts_accpath =
803 ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
804 p->fts_info = FTS_NSOK;
805 } else {
806 /* Build a file name for fts_stat to stat. */
807 if (ISSET(FTS_NOCHDIR)) {
808 p->fts_accpath = p->fts_path;
809 memmove(cp, p->fts_name, p->fts_namelen + 1);
810 } else
811 p->fts_accpath = p->fts_name;
812 /* Stat it. */
813 p->fts_info = fts_stat(sp, p, 0);
814
815 /* Decrement link count if applicable. */
816 if (nlinks > 0 && (p->fts_info == FTS_D ||
817 p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
818 --nlinks;
819 }
820
821 /* We walk in directory order so "ls -f" doesn't get upset. */
822 p->fts_link = NULL;
823 if (head == NULL)
824 head = tail = p;
825 else {
826 tail->fts_link = p;
827 tail = p;
828 }
829 ++nitems;
830 }
831 if (dirp)
832 (void)closedir(dirp);
833
834 /*
835 * If realloc() changed the address of the path, adjust the
836 * addresses for the rest of the tree and the dir list.
837 */
838 if (doadjust)
839 fts_padjust(sp, head);
840
841 /*
842 * If not changing directories, reset the path back to original
843 * state.
844 */
845 if (ISSET(FTS_NOCHDIR))
846 sp->fts_path[cur->fts_pathlen] = '\0';
847
848 /*
849 * If descended after called from fts_children or after called from
850 * fts_read and nothing found, get back. At the root level we use
851 * the saved fd; if one of fts_open()'s arguments is a relative path
852 * to an empty directory, we wind up here with no other way back. If
853 * can't get back, we're done.
854 */
855 if (descend && (type == BCHILD || !nitems) &&
856 (cur->fts_level == FTS_ROOTLEVEL ?
857 FCHDIR(sp, sp->fts_rfd) :
858 fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
859 cur->fts_info = FTS_ERR;
860 SET(FTS_STOP);
861 return (NULL);
862 }
863
864 /* If didn't find anything, return NULL. */
865 if (!nitems) {
866 if (type == BREAD)
867 cur->fts_info = FTS_DP;
868 return (NULL);
869 }
870
871 /* Sort the entries. */
872 if (sp->fts_compar && nitems > 1)
873 head = fts_sort(sp, head, nitems);
874 return (head);
875}
876
877static int
878fts_stat(sp, p, follow)
879 FTS *sp;
880 FTSENT *p;
881 int follow;
882{
883 FTSENT *t;
884 dev_t dev;
885 ino_t ino;
886 struct stat *sbp, sb;
887 int saved_errno;
888
889 /* If user needs stat info, stat buffer already allocated. */
890 sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
891
892#ifdef FTS_WHITEOUT
893 /* Check for whiteout. */
894 if (p->fts_flags & FTS_ISW) {
895 if (sbp != &sb) {
896 memset(sbp, '\0', sizeof(*sbp));
897 sbp->st_mode = S_IFWHT;
898 }
899 return (FTS_W);
900 }
901#endif
902
903 /*
904 * If doing a logical walk, or application requested FTS_FOLLOW, do
905 * a stat(2). If that fails, check for a non-existent symlink. If
906 * fail, set the errno from the stat call.
907 */
908 if (ISSET(FTS_LOGICAL) || follow) {
909 if (stat(p->fts_accpath, sbp)) {
910 saved_errno = errno;
911 if (!lstat(p->fts_accpath, sbp)) {
912 errno = 0;
913 return (FTS_SLNONE);
914 }
915 p->fts_errno = saved_errno;
916 goto err;
917 }
918 } else if (lstat(p->fts_accpath, sbp)) {
919 p->fts_errno = errno;
920err: memset(sbp, 0, sizeof(struct stat));
921 return (FTS_NS);
922 }
923
924 if (S_ISDIR(sbp->st_mode)) {
925 /*
926 * Set the device/inode. Used to find cycles and check for
927 * crossing mount points. Also remember the link count, used
928 * in fts_build to limit the number of stat calls. It is
929 * understood that these fields are only referenced if fts_info
930 * is set to FTS_D.
931 */
932 dev = p->fts_dev = sbp->st_dev;
933 ino = p->fts_ino = sbp->st_ino;
934 p->fts_nlink = sbp->st_nlink;
935
936 if (ISDOT(p->fts_name))
937 return (FTS_DOT);
938
939 /*
940 * Cycle detection is done by brute force when the directory
941 * is first encountered. If the tree gets deep enough or the
942 * number of symbolic links to directories is high enough,
943 * something faster might be worthwhile.
944 */
945 for (t = p->fts_parent;
946 t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
947 if (ino == t->fts_ino && dev == t->fts_dev) {
948 p->fts_cycle = t;
949 return (FTS_DC);
950 }
951 return (FTS_D);
952 }
953 if (S_ISLNK(sbp->st_mode))
954 return (FTS_SL);
955 if (S_ISREG(sbp->st_mode))
956 return (FTS_F);
957 return (FTS_DEFAULT);
958}
959
960/*
961 * The comparison function takes pointers to pointers to FTSENT structures.
962 * Qsort wants a comparison function that takes pointers to void.
963 * (Both with appropriate levels of const-poisoning, of course!)
964 * Use a trampoline function to deal with the difference.
965 */
966static int
967fts_compar(const void *a, const void *b)
968{
969 FTS *parent;
970
971 parent = (*(const FTSENT * const *)a)->fts_fts;
972 return (*parent->fts_compar)(a, b);
973}
974
975static FTSENT *
976fts_sort(sp, head, nitems)
977 FTS *sp;
978 FTSENT *head;
979 size_t nitems;
980{
981 FTSENT **ap, *p;
982
983 /*
984 * Construct an array of pointers to the structures and call qsort(3).
985 * Reassemble the array in the order returned by qsort. If unable to
986 * sort for memory reasons, return the directory entries in their
987 * current order. Allocate enough space for the current needs plus
988 * 40 so don't realloc one entry at a time.
989 */
990 if (nitems > sp->fts_nitems) {
991 sp->fts_nitems = nitems + 40;
992 if ((sp->fts_array = reallocf(sp->fts_array,
993 sp->fts_nitems * sizeof(FTSENT *))) == NULL) {
994 sp->fts_nitems = 0;
995 return (head);
996 }
997 }
998 for (ap = sp->fts_array, p = head; p; p = p->fts_link)
999 *ap++ = p;
1000 qsort(sp->fts_array, nitems, sizeof(FTSENT *), fts_compar);
1001 for (head = *(ap = sp->fts_array); --nitems; ++ap)
1002 ap[0]->fts_link = ap[1];
1003 ap[0]->fts_link = NULL;
1004 return (head);
1005}
1006
1007static FTSENT *
1008fts_alloc(sp, name, namelen)
1009 FTS *sp;
1010 char *name;
1011 size_t namelen;
1012{
1013 FTSENT *p;
1014 size_t len;
1015
1016 struct ftsent_withstat {
1017 FTSENT ent;
1018 struct stat statbuf;
1019 };
1020
1021 /*
1022 * The file name is a variable length array and no stat structure is
1023 * necessary if the user has set the nostat bit. Allocate the FTSENT
1024 * structure, the file name and the stat structure in one chunk, but
1025 * be careful that the stat structure is reasonably aligned.
1026 */
1027 if (ISSET(FTS_NOSTAT))
1028 len = sizeof(FTSENT) + namelen + 1;
1029 else
1030 len = sizeof(struct ftsent_withstat) + namelen + 1;
1031
1032 if ((p = malloc(len)) == NULL)
1033 return (NULL);
1034
1035 if (ISSET(FTS_NOSTAT)) {
1036 p->fts_name = (char *)(p + 1);
1037 p->fts_statp = NULL;
1038 } else {
1039 p->fts_name = (char *)((struct ftsent_withstat *)p + 1);
1040 p->fts_statp = &((struct ftsent_withstat *)p)->statbuf;
1041 }
1042
1043 /* Copy the name and guarantee NUL termination. */
1044 memcpy(p->fts_name, name, namelen);
1045 p->fts_name[namelen] = '\0';
1046 p->fts_namelen = namelen;
1047 p->fts_path = sp->fts_path;
1048 p->fts_errno = 0;
1049 p->fts_flags = 0;
1050 p->fts_instr = FTS_NOINSTR;
1051 p->fts_number = 0;
1052 p->fts_pointer = NULL;
1053 p->fts_fts = sp;
1054 return (p);
1055}
1056
1057static void
1058fts_lfree(head)
1059 FTSENT *head;
1060{
1061 FTSENT *p;
1062
1063 /* Free a linked list of structures. */
1064 while ((p = head)) {
1065 head = head->fts_link;
1066 free(p);
1067 }
1068}
1069
1070/*
1071 * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
1072 * Most systems will allow creation of paths much longer than MAXPATHLEN, even
1073 * though the kernel won't resolve them. Add the size (not just what's needed)
1074 * plus 256 bytes so don't realloc the path 2 bytes at a time.
1075 */
1076static int
1077fts_palloc(sp, more)
1078 FTS *sp;
1079 size_t more;
1080{
1081
1082 sp->fts_pathlen += more + 256;
1083 sp->fts_path = reallocf(sp->fts_path, sp->fts_pathlen);
1084 return (sp->fts_path == NULL);
1085}
1086
1087/*
1088 * When the path is realloc'd, have to fix all of the pointers in structures
1089 * already returned.
1090 */
1091static void
1092fts_padjust(sp, head)
1093 FTS *sp;
1094 FTSENT *head;
1095{
1096 FTSENT *p;
1097 char *addr = sp->fts_path;
1098
1099#define ADJUST(p) do { \
1100 if ((p)->fts_accpath != (p)->fts_name) { \
1101 (p)->fts_accpath = \
1102 (char *)addr + ((p)->fts_accpath - (p)->fts_path); \
1103 } \
1104 (p)->fts_path = addr; \
1105} while (0)
1106 /* Adjust the current set of children. */
1107 for (p = sp->fts_child; p; p = p->fts_link)
1108 ADJUST(p);
1109
1110 /* Adjust the rest of the tree, including the current level. */
1111 for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
1112 ADJUST(p);
1113 p = p->fts_link ? p->fts_link : p->fts_parent;
1114 }
1115}
1116
1117static size_t
1118fts_maxarglen(argv)
1119 char * const *argv;
1120{
1121 size_t len, max;
1122
1123 for (max = 0; *argv; ++argv)
1124 if ((len = strlen(*argv)) > max)
1125 max = len;
1126 return (max + 1);
1127}
1128
1129/*
1130 * Change to dir specified by fd or p->fts_accpath without getting
1131 * tricked by someone changing the world out from underneath us.
1132 * Assumes p->fts_dev and p->fts_ino are filled in.
1133 */
1134static int
1135fts_safe_changedir(sp, p, fd, path)
1136 FTS *sp;
1137 FTSENT *p;
1138 int fd;
1139 char *path;
1140{
1141 int ret, oerrno, newfd;
1142 struct stat sb;
1143
1144 newfd = fd;
1145 if (ISSET(FTS_NOCHDIR))
1146 return (0);
1147 if (fd < 0 && (newfd = _open(path, O_RDONLY, 0)) < 0)
1148 return (-1);
1149 if (_fstat(newfd, &sb)) {
1150 ret = -1;
1151 goto bail;
1152 }
1153 if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
1154 errno = ENOENT; /* disinformation */
1155 ret = -1;
1156 goto bail;
1157 }
1158 ret = fchdir(newfd);
1159bail:
1160 oerrno = errno;
1161 if (fd < 0)
1162 (void)_close(newfd);
1163 errno = oerrno;
1164 return (ret);
1165}
1166
1167/*
1168 * Check if the filesystem for "ent" has UFS-style links.
1169 */
1170static int
1171fts_ufslinks(FTS *sp, const FTSENT *ent)
1172{
1173 struct _fts_private *priv;
1174 const char **cpp;
1175
1176 priv = (struct _fts_private *)sp;
1177 /*
1178 * If this node's device is different from the previous, grab
1179 * the filesystem information, and decide on the reliability
1180 * of the link information from this filesystem for stat(2)
1181 * avoidance.
1182 */
1183 if (priv->ftsp_dev != ent->fts_dev) {
1184 if (statfs(ent->fts_path, &priv->ftsp_statfs) != -1) {
1185 priv->ftsp_dev = ent->fts_dev;
1186 priv->ftsp_linksreliable = 0;
1187 for (cpp = ufslike_filesystems; *cpp; cpp++) {
1188 if (strcmp(priv->ftsp_statfs.f_fstypename,
1189 *cpp) == 0) {
1190 priv->ftsp_linksreliable = 1;
1191 break;
1192 }
1193 }
1194 } else {
1195 priv->ftsp_linksreliable = 0;
1196 }
1197 }
1198 return (priv->ftsp_linksreliable);
1199}