compat_fts.c

   1 #include "config.h"
   2
   3 #if HAVE_FTS
   4
   5 int dummy;
   6
   7 #else
   8
   9 /*      $Id: compat_fts.c,v 1.4 2014/08/17 20:45:59 schwarze Exp $      */
  10 /*      $OpenBSD: fts.c,v 1.46 2014/05/25 17:47:04 tedu Exp $   */
  11
  12 /*-
  13  * Copyright (c) 1990, 1993, 1994
  14  *      The Regents of the University of California.  All rights reserved.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  * 3. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 #include <sys/param.h>
  42 #include <sys/stat.h>
  43 #include <sys/types.h>
  44
  45 #include <dirent.h>
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <limits.h>
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #include <unistd.h>
  52 #include "compat_fts.h"
  53
  54 static FTSENT   *fts_alloc(FTS *, const char *, size_t);
  55 static FTSENT   *fts_build(FTS *);
  56 static void      fts_lfree(FTSENT *);
  57 static void      fts_load(FTS *, FTSENT *);
  58 static size_t    fts_maxarglen(char * const *);
  59 static void      fts_padjust(FTS *, FTSENT *);
  60 static int       fts_palloc(FTS *, size_t);
  61 static unsigned short    fts_stat(FTS *, FTSENT *);
  62 static int       fts_safe_changedir(FTS *, FTSENT *, int, const char *);
  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 *
  73 fts_open(char * const *argv, int options, void *dummy)
  74 {
  75         FTS *sp;
  76         FTSENT *p, *root;
  77         int nitems;
  78         FTSENT *parent, *tmp;
  79         size_t len;
  80
  81         /* Options check. */
  82         if (options & ~FTS_OPTIONMASK) {
  83                 errno = EINVAL;
  84                 return (NULL);
  85         }
  86
  87         /* Allocate/initialize the stream */
  88         if ((sp = calloc(1, sizeof(FTS))) == NULL)
  89                 return (NULL);
  90         sp->fts_options = options;
  91
  92         /*
  93          * Start out with 1K of path space, and enough, in any case,
  94          * to hold the user's paths.
  95          */
  96         if (fts_palloc(sp, MAX(fts_maxarglen(argv), PATH_MAX)))
  97                 goto mem1;
  98
  99         /* Allocate/initialize root's parent. */
 100         if ((parent = fts_alloc(sp, "", 0)) == NULL)
 101                 goto mem2;
 102         parent->fts_level = FTS_ROOTPARENTLEVEL;
 103
 104         /* Allocate/initialize root(s). */
 105         for (root = NULL, nitems = 0; *argv; ++argv, ++nitems) {
 106                 /* Don't allow zero-length paths. */
 107                 if ((len = strlen(*argv)) == 0) {
 108                         errno = ENOENT;
 109                         goto mem3;
 110                 }
 111
 112                 if ((p = fts_alloc(sp, *argv, len)) == NULL)
 113                         goto mem3;
 114                 p->fts_level = FTS_ROOTLEVEL;
 115                 p->fts_parent = parent;
 116                 p->fts_accpath = p->fts_name;
 117                 p->fts_info = fts_stat(sp, p);
 118
 119                 /* Command-line "." and ".." are real directories. */
 120                 if (p->fts_info == FTS_DOT)
 121                         p->fts_info = FTS_D;
 122
 123                 p->fts_link = NULL;
 124                 if (root == NULL)
 125                         tmp = root = p;
 126                 else {
 127                         tmp->fts_link = p;
 128                         tmp = p;
 129                 }
 130         }
 131
 132         /*
 133          * Allocate a dummy pointer and make fts_read think that we've just
 134          * finished the node before the root(s); set p->fts_info to FTS_INIT
 135          * so that everything about the "current" node is ignored.
 136          */
 137         if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
 138                 goto mem3;
 139         sp->fts_cur->fts_link = root;
 140         sp->fts_cur->fts_info = FTS_INIT;
 141
 142         /*
 143          * If using chdir(2), grab a file descriptor pointing to dot to ensure
 144          * that we can get back here; this could be avoided for some paths,
 145          * but almost certainly not worth the effort.  Slashes, symbolic links,
 146          * and ".." are all fairly nasty problems.  Note, if we can't get the
 147          * descriptor we run anyway, just more slowly.
 148          */
 149         if (!ISSET(FTS_NOCHDIR) && (sp->fts_rfd = open(".", O_RDONLY, 0)) < 0)
 150                 SET(FTS_NOCHDIR);
 151
 152         if (nitems == 0)
 153                 free(parent);
 154
 155         return (sp);
 156
 157 mem3:   fts_lfree(root);
 158         free(parent);
 159 mem2:   free(sp->fts_path);
 160 mem1:   free(sp);
 161         return (NULL);
 162 }
 163
 164 static void
 165 fts_load(FTS *sp, FTSENT *p)
 166 {
 167         size_t len;
 168         char *cp;
 169
 170         /*
 171          * Load the stream structure for the next traversal.  Since we don't
 172          * actually enter the directory until after the preorder visit, set
 173          * the fts_accpath field specially so the chdir gets done to the right
 174          * place and the user can access the first node.  From fts_open it's
 175          * known that the path will fit.
 176          */
 177         len = p->fts_pathlen = p->fts_namelen;
 178         memmove(sp->fts_path, p->fts_name, len + 1);
 179         if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
 180                 len = strlen(++cp);
 181                 memmove(p->fts_name, cp, len + 1);
 182                 p->fts_namelen = len;
 183         }
 184         p->fts_accpath = p->fts_path = sp->fts_path;
 185         sp->fts_dev = p->fts_dev;
 186 }
 187
 188 int
 189 fts_close(FTS *sp)
 190 {
 191         FTSENT *freep, *p;
 192         int rfd, error = 0;
 193
 194         /*
 195          * This still works if we haven't read anything -- the dummy structure
 196          * points to the root list, so we step through to the end of the root
 197          * list which has a valid parent pointer.
 198          */
 199         if (sp->fts_cur) {
 200                 for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
 201                         freep = p;
 202                         p = p->fts_link ? p->fts_link : p->fts_parent;
 203                         free(freep);
 204                 }
 205                 free(p);
 206         }
 207
 208         /* Stash the original directory fd if needed. */
 209         rfd = ISSET(FTS_NOCHDIR) ? -1 : sp->fts_rfd;
 210
 211         /* Free up child linked list, sort array, path buffer, stream ptr.*/
 212         if (sp->fts_child)
 213                 fts_lfree(sp->fts_child);
 214         free(sp->fts_path);
 215         free(sp);
 216
 217         /* Return to original directory, checking for error. */
 218         if (rfd != -1) {
 219                 int saved_errno;
 220                 error = fchdir(rfd);
 221                 saved_errno = errno;
 222                 (void)close(rfd);
 223                 errno = saved_errno;
 224         }
 225
 226         return (error);
 227 }
 228
 229 /*
 230  * Special case of "/" at the end of the path so that slashes aren't
 231  * appended which would cause paths to be written as "....//foo".
 232  */
 233 #define NAPPEND(p)                                                      \
 234         (p->fts_path[p->fts_pathlen - 1] == '/'                         \
 235             ? p->fts_pathlen - 1 : p->fts_pathlen)
 236
 237 FTSENT *
 238 fts_read(FTS *sp)
 239 {
 240         FTSENT *p, *tmp;
 241         int instr;
 242         char *t;
 243
 244         /* If finished or unrecoverable error, return NULL. */
 245         if (sp->fts_cur == NULL || ISSET(FTS_STOP))
 246                 return (NULL);
 247
 248         /* Set current node pointer. */
 249         p = sp->fts_cur;
 250
 251         /* Save and zero out user instructions. */
 252         instr = p->fts_instr;
 253         p->fts_instr = FTS_NOINSTR;
 254
 255         /* Directory in pre-order. */
 256         if (p->fts_info == FTS_D) {
 257                 /* If skipped or crossed mount point, do post-order visit. */
 258                 if (instr == FTS_SKIP ||
 259                     (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
 260                         if (sp->fts_child) {
 261                                 fts_lfree(sp->fts_child);
 262                                 sp->fts_child = NULL;
 263                         }
 264                         p->fts_info = FTS_DP;
 265                         return (p);
 266                 }
 267
 268                 /*
 269                  * Cd to the subdirectory.
 270                  *
 271                  * If have already read and now fail to chdir, whack the list
 272                  * to make the names come out right, and set the parent errno
 273                  * so the application will eventually get an error condition.
 274                  * Set the FTS_DONTCHDIR flag so that when we logically change
 275                  * directories back to the parent we don't do a chdir.
 276                  *
 277                  * If haven't read do so.  If the read fails, fts_build sets
 278                  * FTS_STOP or the fts_info field of the node.
 279                  */
 280                 if (sp->fts_child) {
 281                         if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
 282                                 p->fts_errno = errno;
 283                                 p->fts_flags |= FTS_DONTCHDIR;
 284                                 for (p = sp->fts_child; p; p = p->fts_link)
 285                                         p->fts_accpath =
 286                                             p->fts_parent->fts_accpath;
 287                         }
 288                 } else if ((sp->fts_child = fts_build(sp)) == NULL) {
 289                         if (ISSET(FTS_STOP))
 290                                 return (NULL);
 291                         return (p);
 292                 }
 293                 p = sp->fts_child;
 294                 sp->fts_child = NULL;
 295                 goto name;
 296         }
 297
 298         /* Move to the next node on this level. */
 299 next:   tmp = p;
 300         if ((p = p->fts_link)) {
 301                 free(tmp);
 302
 303                 /*
 304                  * If reached the top, return to the original directory (or
 305                  * the root of the tree), and load the paths for the next root.
 306                  */
 307                 if (p->fts_level == FTS_ROOTLEVEL) {
 308                         if (FCHDIR(sp, sp->fts_rfd)) {
 309                                 SET(FTS_STOP);
 310                                 return (NULL);
 311                         }
 312                         fts_load(sp, p);
 313                         return (sp->fts_cur = p);
 314                 }
 315
 316                 /*
 317                  * User may have called fts_set on the node.  If skipped,
 318                  * ignore.  If followed, get a file descriptor so we can
 319                  * get back if necessary.
 320                  */
 321                 if (p->fts_instr == FTS_SKIP)
 322                         goto next;
 323
 324 name:           t = sp->fts_path + NAPPEND(p->fts_parent);
 325                 *t++ = '/';
 326                 memmove(t, p->fts_name, p->fts_namelen + 1);
 327                 return (sp->fts_cur = p);
 328         }
 329
 330         /* Move up to the parent node. */
 331         p = tmp->fts_parent;
 332         free(tmp);
 333
 334         if (p->fts_level == FTS_ROOTPARENTLEVEL) {
 335                 /*
 336                  * Done; free everything up and set errno to 0 so the user
 337                  * can distinguish between error and EOF.
 338                  */
 339                 free(p);
 340                 errno = 0;
 341                 return (sp->fts_cur = NULL);
 342         }
 343
 344         /* NUL terminate the pathname. */
 345         sp->fts_path[p->fts_pathlen] = '\0';
 346
 347         /*
 348          * Return to the parent directory.  If at a root node or came through
 349          * a symlink, go back through the file descriptor.  Otherwise, cd up
 350          * one directory.
 351          */
 352         if (p->fts_level == FTS_ROOTLEVEL) {
 353                 if (FCHDIR(sp, sp->fts_rfd)) {
 354                         SET(FTS_STOP);
 355                         sp->fts_cur = p;
 356                         return (NULL);
 357                 }
 358         } else if (!(p->fts_flags & FTS_DONTCHDIR) &&
 359             fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
 360                 SET(FTS_STOP);
 361                 sp->fts_cur = p;
 362                 return (NULL);
 363         }
 364         p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
 365         return (sp->fts_cur = p);
 366 }
 367
 368 /*
 369  * Fts_set takes the stream as an argument although it's not used in this
 370  * implementation; it would be necessary if anyone wanted to add global
 371  * semantics to fts using fts_set.  An error return is allowed for similar
 372  * reasons.
 373  */
 374 /* ARGSUSED */
 375 int
 376 fts_set(FTS *sp, FTSENT *p, int instr)
 377 {
 378         if (instr && instr != FTS_NOINSTR && instr != FTS_SKIP) {
 379                 errno = EINVAL;
 380                 return (1);
 381         }
 382         p->fts_instr = instr;
 383         return (0);
 384 }
 385
 386 /*
 387  * This is the tricky part -- do not casually change *anything* in here.  The
 388  * idea is to build the linked list of entries that are used by fts_children
 389  * and fts_read.  There are lots of special cases.
 390  *
 391  * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
 392  * set and it's a physical walk (so that symbolic links can't be directories),
 393  * we can do things quickly.  First, if it's a 4.4BSD file system, the type
 394  * of the file is in the directory entry.  Otherwise, we assume that the number
 395  * of subdirectories in a node is equal to the number of links to the parent.
 396  * The former skips all stat calls.  The latter skips stat calls in any leaf
 397  * directories and for any files after the subdirectories in the directory have
 398  * been found, cutting the stat calls by about 2/3.
 399  */
 400 static FTSENT *
 401 fts_build(FTS *sp)
 402 {
 403         struct dirent *dp;
 404         FTSENT *p, *head;
 405         FTSENT *cur, *tail;
 406         DIR *dirp;
 407         void *oldaddr;
 408         size_t dlen, len, maxlen;
 409         int nitems, cderrno, descend, level, nlinks, nostat, doadjust;
 410         int saved_errno;
 411         char *cp;
 412
 413         /* Set current node pointer. */
 414         cur = sp->fts_cur;
 415
 416         /*
 417          * Open the directory for reading.  If this fails, we're done.
 418          * If being called from fts_read, set the fts_info field.
 419          */
 420         if ((dirp = opendir(cur->fts_accpath)) == NULL) {
 421                 cur->fts_info = FTS_DNR;
 422                 cur->fts_errno = errno;
 423                 return (NULL);
 424         }
 425
 426         /*
 427          * Nlinks is the number of possible entries of type directory in the
 428          * directory if we're cheating on stat calls, 0 if we're not doing
 429          * any stat calls at all, -1 if we're doing stats on everything.
 430          */
 431         nlinks = -1;
 432         nostat = 0;
 433
 434         /*
 435          * If we're going to need to stat anything or we want to descend
 436          * and stay in the directory, chdir.  If this fails we keep going,
 437          * but set a flag so we don't chdir after the post-order visit.
 438          * We won't be able to stat anything, but we can still return the
 439          * names themselves.  Note, that since fts_read won't be able to
 440          * chdir into the directory, it will have to return different path
 441          * names than before, i.e. "a/b" instead of "b".  Since the node
 442          * has already been visited in pre-order, have to wait until the
 443          * post-order visit to return the error.  There is a special case
 444          * here, if there was nothing to stat then it's not an error to
 445          * not be able to stat.  This is all fairly nasty.  If a program
 446          * needed sorted entries or stat information, they had better be
 447          * checking FTS_NS on the returned nodes.
 448          */
 449         cderrno = 0;
 450         if (fts_safe_changedir(sp, cur, dirfd(dirp), NULL)) {
 451                 if (nlinks)
 452                         cur->fts_errno = errno;
 453                 cur->fts_flags |= FTS_DONTCHDIR;
 454                 descend = 0;
 455                 cderrno = errno;
 456                 (void)closedir(dirp);
 457                 dirp = NULL;
 458         } else
 459                 descend = 1;
 460
 461         /*
 462          * Figure out the max file name length that can be stored in the
 463          * current path -- the inner loop allocates more path as necessary.
 464          * We really wouldn't have to do the maxlen calculations here, we
 465          * could do them in fts_read before returning the path, but it's a
 466          * lot easier here since the length is part of the dirent structure.
 467          *
 468          * If not changing directories set a pointer so that can just append
 469          * each new name into the path.
 470          */
 471         len = NAPPEND(cur);
 472         if (ISSET(FTS_NOCHDIR)) {
 473                 cp = sp->fts_path + len;
 474                 *cp++ = '/';
 475         }
 476         len++;
 477         maxlen = sp->fts_pathlen - len;
 478
 479         /*
 480          * fts_level is signed so we must prevent it from wrapping
 481          * around to FTS_ROOTLEVEL and FTS_ROOTPARENTLEVEL.
 482          */
 483         level = cur->fts_level;
 484         if (level < FTS_MAXLEVEL)
 485             level++;
 486
 487         /* Read the directory, attaching each entry to the `link' pointer. */
 488         doadjust = 0;
 489         for (head = tail = NULL, nitems = 0; dirp && (dp = readdir(dirp));) {
 490                 if (ISDOT(dp->d_name))
 491                         continue;
 492
 493 #if HAVE_DIRENT_NAMLEN
 494                 dlen = dp->d_namlen;
 495 #else
 496                 dlen = strlen(dp->d_name);
 497 #endif
 498
 499                 if (!(p = fts_alloc(sp, dp->d_name, dlen)))
 500                         goto mem1;
 501                 if (dlen >= maxlen) {   /* include space for NUL */
 502                         oldaddr = sp->fts_path;
 503                         if (fts_palloc(sp, dlen + len + 1)) {
 504                                 /*
 505                                  * No more memory for path or structures.  Save
 506                                  * errno, free up the current structure and the
 507                                  * structures already allocated.
 508                                  */
 509 mem1:                           saved_errno = errno;
 510                                 if (p)
 511                                         free(p);
 512                                 fts_lfree(head);
 513                                 (void)closedir(dirp);
 514                                 cur->fts_info = FTS_ERR;
 515                                 SET(FTS_STOP);
 516                                 errno = saved_errno;
 517                                 return (NULL);
 518                         }
 519                         /* Did realloc() change the pointer? */
 520                         if (oldaddr != sp->fts_path) {
 521                                 doadjust = 1;
 522                                 if (ISSET(FTS_NOCHDIR))
 523                                         cp = sp->fts_path + len;
 524                         }
 525                         maxlen = sp->fts_pathlen - len;
 526                 }
 527
 528                 p->fts_level = level;
 529                 p->fts_parent = sp->fts_cur;
 530                 p->fts_pathlen = len + dlen;
 531                 if (p->fts_pathlen < len) {
 532                         /*
 533                          * If we wrap, free up the current structure and
 534                          * the structures already allocated, then error
 535                          * out with ENAMETOOLONG.
 536                          */
 537                         free(p);
 538                         fts_lfree(head);
 539                         (void)closedir(dirp);
 540                         cur->fts_info = FTS_ERR;
 541                         SET(FTS_STOP);
 542                         errno = ENAMETOOLONG;
 543                         return (NULL);
 544                 }
 545
 546                 if (cderrno) {
 547                         if (nlinks) {
 548                                 p->fts_info = FTS_NS;
 549                                 p->fts_errno = cderrno;
 550                         } else
 551                                 p->fts_info = FTS_NSOK;
 552                         p->fts_accpath = cur->fts_accpath;
 553                 } else if (nlinks == 0
 554 #ifdef DT_DIR
 555                     || (nostat &&
 556                     dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN)
 557 #endif
 558                     ) {
 559                         p->fts_accpath =
 560                             ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
 561                         p->fts_info = FTS_NSOK;
 562                 } else {
 563                         /* Build a file name for fts_stat to stat. */
 564                         if (ISSET(FTS_NOCHDIR)) {
 565                                 p->fts_accpath = p->fts_path;
 566                                 memmove(cp, p->fts_name, p->fts_namelen + 1);
 567                         } else
 568                                 p->fts_accpath = p->fts_name;
 569                         /* Stat it. */
 570                         p->fts_info = fts_stat(sp, p);
 571
 572                         /* Decrement link count if applicable. */
 573                         if (nlinks > 0 && (p->fts_info == FTS_D ||
 574                             p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
 575                                 --nlinks;
 576                 }
 577
 578                 /* We walk in directory order so "ls -f" doesn't get upset. */
 579                 p->fts_link = NULL;
 580                 if (head == NULL)
 581                         head = tail = p;
 582                 else {
 583                         tail->fts_link = p;
 584                         tail = p;
 585                 }
 586                 ++nitems;
 587         }
 588         if (dirp)
 589                 (void)closedir(dirp);
 590
 591         /*
 592          * If realloc() changed the address of the path, adjust the
 593          * addresses for the rest of the tree and the dir list.
 594          */
 595         if (doadjust)
 596                 fts_padjust(sp, head);
 597
 598         /*
 599          * If not changing directories, reset the path back to original
 600          * state.
 601          */
 602         if (ISSET(FTS_NOCHDIR)) {
 603                 if (len == sp->fts_pathlen || nitems == 0)
 604                         --cp;
 605                 *cp = '\0';
 606         }
 607
 608         /*
 609          * If descended after called from fts_children or after called from
 610          * fts_read and nothing found, get back.  At the root level we use
 611          * the saved fd; if one of fts_open()'s arguments is a relative path
 612          * to an empty directory, we wind up here with no other way back.  If
 613          * can't get back, we're done.
 614          */
 615         if (descend && !nitems &&
 616             (cur->fts_level == FTS_ROOTLEVEL ? FCHDIR(sp, sp->fts_rfd) :
 617             fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
 618                 cur->fts_info = FTS_ERR;
 619                 SET(FTS_STOP);
 620                 return (NULL);
 621         }
 622
 623         /* If didn't find anything, return NULL. */
 624         if (!nitems) {
 625                 cur->fts_info = FTS_DP;
 626                 return (NULL);
 627         }
 628         return (head);
 629 }
 630
 631 static unsigned short
 632 fts_stat(FTS *sp, FTSENT *p)
 633 {
 634         FTSENT *t;
 635         dev_t dev;
 636         ino_t ino;
 637         struct stat *sbp;
 638
 639         /* If user needs stat info, stat buffer already allocated. */
 640         sbp = p->fts_statp;
 641
 642         if (lstat(p->fts_accpath, sbp)) {
 643                 p->fts_errno = errno;
 644                 memset(sbp, 0, sizeof(struct stat));
 645                 return (FTS_NS);
 646         }
 647
 648         if (S_ISDIR(sbp->st_mode)) {
 649                 /*
 650                  * Set the device/inode.  Used to find cycles and check for
 651                  * crossing mount points.  Also remember the link count, used
 652                  * in fts_build to limit the number of stat calls.  It is
 653                  * understood that these fields are only referenced if fts_info
 654                  * is set to FTS_D.
 655                  */
 656                 dev = p->fts_dev = sbp->st_dev;
 657                 ino = p->fts_ino = sbp->st_ino;
 658                 p->fts_nlink = sbp->st_nlink;
 659
 660                 if (ISDOT(p->fts_name))
 661                         return (FTS_DOT);
 662
 663                 /*
 664                  * Cycle detection is done by brute force when the directory
 665                  * is first encountered.  If the tree gets deep enough or the
 666                  * number of symbolic links to directories is high enough,
 667                  * something faster might be worthwhile.
 668                  */
 669                 for (t = p->fts_parent;
 670                     t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
 671                         if (ino == t->fts_ino && dev == t->fts_dev) {
 672                                 p->fts_cycle = t;
 673                                 return (FTS_DC);
 674                         }
 675                 return (FTS_D);
 676         }
 677         if (S_ISLNK(sbp->st_mode))
 678                 return (FTS_SL);
 679         if (S_ISREG(sbp->st_mode))
 680                 return (FTS_F);
 681         return (FTS_DEFAULT);
 682 }
 683
 684 static FTSENT *
 685 fts_alloc(FTS *sp, const char *name, size_t namelen)
 686 {
 687         FTSENT *p;
 688         size_t len;
 689
 690         len = sizeof(FTSENT) + namelen;
 691         if ((p = calloc(1, len)) == NULL)
 692                 return (NULL);
 693
 694         p->fts_path = sp->fts_path;
 695         p->fts_namelen = namelen;
 696         p->fts_instr = FTS_NOINSTR;
 697         p->fts_statp = malloc(sizeof(struct stat));
 698         if (p->fts_statp == NULL) {
 699                 free(p);
 700                 return (NULL);
 701         }
 702         memcpy(p->fts_name, name, namelen);
 703
 704         return (p);
 705 }
 706
 707 static void
 708 fts_lfree(FTSENT *head)
 709 {
 710         FTSENT *p;
 711
 712         /* Free a linked list of structures. */
 713         while ((p = head)) {
 714                 head = head->fts_link;
 715                 free(p);
 716         }
 717 }
 718
 719 /*
 720  * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
 721  * Most systems will allow creation of paths much longer than PATH_MAX, even
 722  * though the kernel won't resolve them.  Add the size (not just what's needed)
 723  * plus 256 bytes so don't realloc the path 2 bytes at a time.
 724  */
 725 static int
 726 fts_palloc(FTS *sp, size_t more)
 727 {
 728         char *p;
 729
 730         /*
 731          * Check for possible wraparound.
 732          */
 733         more += 256;
 734         if (sp->fts_pathlen + more < sp->fts_pathlen) {
 735                 if (sp->fts_path)
 736                         free(sp->fts_path);
 737                 sp->fts_path = NULL;
 738                 errno = ENAMETOOLONG;
 739                 return (1);
 740         }
 741         sp->fts_pathlen += more;
 742         p = realloc(sp->fts_path, sp->fts_pathlen);
 743         if (p == NULL) {
 744                 if (sp->fts_path)
 745                         free(sp->fts_path);
 746                 sp->fts_path = NULL;
 747                 return (1);
 748         }
 749         sp->fts_path = p;
 750         return (0);
 751 }
 752
 753 /*
 754  * When the path is realloc'd, have to fix all of the pointers in structures
 755  * already returned.
 756  */
 757 static void
 758 fts_padjust(FTS *sp, FTSENT *head)
 759 {
 760         FTSENT *p;
 761         char *addr = sp->fts_path;
 762
 763 #define ADJUST(p) {                                                     \
 764         if ((p)->fts_accpath != (p)->fts_name) {                        \
 765                 (p)->fts_accpath =                                      \
 766                     (char *)addr + ((p)->fts_accpath - (p)->fts_path);  \
 767         }                                                               \
 768         (p)->fts_path = addr;                                           \
 769 }
 770         /* Adjust the current set of children. */
 771         for (p = sp->fts_child; p; p = p->fts_link)
 772                 ADJUST(p);
 773
 774         /* Adjust the rest of the tree, including the current level. */
 775         for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
 776                 ADJUST(p);
 777                 p = p->fts_link ? p->fts_link : p->fts_parent;
 778         }
 779 }
 780
 781 static size_t
 782 fts_maxarglen(char * const *argv)
 783 {
 784         size_t len, max;
 785
 786         for (max = 0; *argv; ++argv)
 787                 if ((len = strlen(*argv)) > max)
 788                         max = len;
 789         return (max + 1);
 790 }
 791
 792 /*
 793  * Change to dir specified by fd or p->fts_accpath without getting
 794  * tricked by someone changing the world out from underneath us.
 795  * Assumes p->fts_dev and p->fts_ino are filled in.
 796  */
 797 static int
 798 fts_safe_changedir(FTS *sp, FTSENT *p, int fd, const char *path)
 799 {
 800         int ret, oerrno, newfd;
 801         struct stat sb;
 802
 803         newfd = fd;
 804         if (ISSET(FTS_NOCHDIR))
 805                 return (0);
 806         if (fd < 0 && (newfd = open(path, O_RDONLY, 0)) < 0)
 807                 return (-1);
 808         if (fstat(newfd, &sb)) {
 809                 ret = -1;
 810                 goto bail;
 811         }
 812         if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
 813                 errno = ENOENT;         /* disinformation */
 814                 ret = -1;
 815                 goto bail;
 816         }
 817         ret = fchdir(newfd);
 818 bail:
 819         oerrno = errno;
 820         if (fd < 0)
 821                 (void)close(newfd);
 822         errno = oerrno;
 823         return (ret);
 824 }
 825
 826 #endif