io/ftw.c

   1 /* File tree walker functions.
   2    Copyright (C) 1996-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <https://www.gnu.org/licenses/>.  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #if __GNUC__
  25 # define alloca __builtin_alloca
  26 #else
  27 # if HAVE_ALLOCA_H
  28 #  include <alloca.h>
  29 # else
  30 #  ifdef _AIX
  31  #  pragma alloca
  32 #  else
  33 char *alloca ();
  34 #  endif
  35 # endif
  36 #endif
  37
  38 #ifdef _LIBC
  39 # include <dirent.h>
  40 # define NAMLEN(dirent) _D_EXACT_NAMLEN (dirent)
  41 #else
  42 # if HAVE_DIRENT_H
  43 #  include <dirent.h>
  44 #  define NAMLEN(dirent) strlen ((dirent)->d_name)
  45 # else
  46 #  define dirent direct
  47 #  define NAMLEN(dirent) (dirent)->d_namlen
  48 #  if HAVE_SYS_NDIR_H
  49 #   include <sys/ndir.h>
  50 #  endif
  51 #  if HAVE_SYS_DIR_H
  52 #   include <sys/dir.h>
  53 #  endif
  54 #  if HAVE_NDIR_H
  55 #   include <ndir.h>
  56 #  endif
  57 # endif
  58 #endif
  59
  60 #include <errno.h>
  61 #include <fcntl.h>
  62 #include <ftw.h>
  63 #include <limits.h>
  64 #include <search.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67 #include <unistd.h>
  68 #include <not-cancel.h>
  69 #include <sys/param.h>
  70 #ifdef _LIBC
  71 # include <include/sys/stat.h>
  72 #else
  73 # include <sys/stat.h>
  74 #endif
  75
  76 #if ! _LIBC && !HAVE_DECL_STPCPY && !defined stpcpy
  77 char *stpcpy ();
  78 #endif
  79
  80 #if ! _LIBC && ! defined HAVE_MEMPCPY && ! defined mempcpy
  81 /* Be CAREFUL that there are no side effects in N.  */
  82 # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
  83 #endif
  84
  85 /* #define NDEBUG 1 */
  86 #include <assert.h>
  87
  88 #ifndef _LIBC
  89 # undef __chdir
  90 # define __chdir chdir
  91 # undef __closedir
  92 # define __closedir closedir
  93 # undef __fchdir
  94 # define __fchdir fchdir
  95 # undef __getcwd
  96 # define __getcwd(P, N) xgetcwd ()
  97 extern char *xgetcwd (void);
  98 # undef __mempcpy
  99 # define __mempcpy mempcpy
 100 # undef __opendir
 101 # define __opendir opendir
 102 # undef __readdir64
 103 # define __readdir64 readdir
 104 # undef __stpcpy
 105 # define __stpcpy stpcpy
 106 # undef __tdestroy
 107 # define __tdestroy tdestroy
 108 # undef __tfind
 109 # define __tfind tfind
 110 # undef __tsearch
 111 # define __tsearch tsearch
 112 # undef dirent64
 113 # define dirent64 dirent
 114 # undef MAX
 115 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 116 #endif
 117
 118 /* Arrange to make lstat calls go through the wrapper function
 119    on systems with an lstat function that does not dereference symlinks
 120    that are specified with a trailing slash.  */
 121 #if ! _LIBC && ! LSTAT_FOLLOWS_SLASHED_SYMLINK
 122 int rpl_lstat (const char *, struct stat *);
 123 # undef lstat
 124 # define lstat(Name, Stat_buf) rpl_lstat(Name, Stat_buf)
 125 #endif
 126
 127 #ifndef __set_errno
 128 # define __set_errno(Val) errno = (Val)
 129 #endif
 130
 131 /* Support for the LFS API version.  */
 132 #ifndef FTW_NAME
 133 # define FTW_NAME ftw
 134 # define NFTW_NAME nftw
 135 # define NFTW_OLD_NAME __old_nftw
 136 # define NFTW_NEW_NAME __new_nftw
 137 # define INO_T ino_t
 138 # define STRUCT_STAT stat
 139 # ifdef _LIBC
 140 #  define LSTAT __lstat
 141 #  define STAT __stat
 142 #  define FSTATAT __fstatat
 143 # else
 144 #  define LSTAT lstat
 145 #  define XTAT stat
 146 #  define FSTATAT fstatat
 147 # endif
 148 # define FTW_FUNC_T __ftw_func_t
 149 # define NFTW_FUNC_T __nftw_func_t
 150 #endif
 151
 152 /* We define PATH_MAX if the system does not provide a definition.
 153    This does not artificially limit any operation.  PATH_MAX is simply
 154    used as a guesstimate for the expected maximal path length.
 155    Buffers will be enlarged if necessary.  */
 156 #ifndef PATH_MAX
 157 # define PATH_MAX 1024
 158 #endif
 159
 160 struct dir_data
 161 {
 162   DIR *stream;
 163   int streamfd;
 164   char *content;
 165 };
 166
 167 struct known_object
 168 {
 169   dev_t dev;
 170   INO_T ino;
 171 };
 172
 173 struct ftw_data
 174 {
 175   /* Array with pointers to open directory streams.  */
 176   struct dir_data **dirstreams;
 177   size_t actdir;
 178   size_t maxdir;
 179
 180   /* Buffer containing name of currently processed object.  */
 181   char *dirbuf;
 182   size_t dirbufsize;
 183
 184   /* Passed as fourth argument to `nftw' callback.  The `base' member
 185      tracks the content of the `dirbuf'.  */
 186   struct FTW ftw;
 187
 188   /* Flags passed to `nftw' function.  0 for `ftw'.  */
 189   int flags;
 190
 191   /* Conversion array for flag values.  It is the identity mapping for
 192      `nftw' calls, otherwise it maps the values to those known by
 193      `ftw'.  */
 194   const int *cvt_arr;
 195
 196   /* Callback function.  We always use the `nftw' form.  */
 197   NFTW_FUNC_T func;
 198
 199   /* Device of starting point.  Needed for FTW_MOUNT.  */
 200   dev_t dev;
 201
 202   /* Data structure for keeping fingerprints of already processed
 203      object.  This is needed when not using FTW_PHYS.  */
 204   void *known_objects;
 205 };
 206
 207
 208 /* Internally we use the FTW_* constants used for `nftw'.  When invoked
 209    as `ftw', map each flag to the subset of values used by `ftw'.  */
 210 static const int nftw_arr[] =
 211 {
 212   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_SL, FTW_DP, FTW_SLN
 213 };
 214
 215 static const int ftw_arr[] =
 216 {
 217   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_F, FTW_D, FTW_NS
 218 };
 219
 220
 221 /* Forward declarations of local functions.  */
 222 static int ftw_dir (struct ftw_data *data, struct STRUCT_STAT *st,
 223                     struct dir_data *old_dir);
 224
 225
 226 static int
 227 object_compare (const void *p1, const void *p2)
 228 {
 229   /* We don't need a sophisticated and useful comparison.  We are only
 230      interested in equality.  However, we must be careful not to
 231      accidentally compare `holes' in the structure.  */
 232   const struct known_object *kp1 = p1, *kp2 = p2;
 233   int cmp1;
 234   cmp1 = (kp1->ino > kp2->ino) - (kp1->ino < kp2->ino);
 235   if (cmp1 != 0)
 236     return cmp1;
 237   return (kp1->dev > kp2->dev) - (kp1->dev < kp2->dev);
 238 }
 239
 240
 241 static int
 242 add_object (struct ftw_data *data, struct STRUCT_STAT *st)
 243 {
 244   struct known_object *newp = malloc (sizeof (struct known_object));
 245   if (newp == NULL)
 246     return -1;
 247   newp->dev = st->st_dev;
 248   newp->ino = st->st_ino;
 249   return __tsearch (newp, &data->known_objects, object_compare) ? 0 : -1;
 250 }
 251
 252
 253 static inline int
 254 find_object (struct ftw_data *data, struct STRUCT_STAT *st)
 255 {
 256   struct known_object obj;
 257   obj.dev = st->st_dev;
 258   obj.ino = st->st_ino;
 259   return __tfind (&obj, &data->known_objects, object_compare) != NULL;
 260 }
 261
 262
 263 static inline int
 264 __attribute ((always_inline))
 265 open_dir_stream (int *dfdp, struct ftw_data *data, struct dir_data *dirp)
 266 {
 267   int result = 0;
 268
 269   if (data->dirstreams[data->actdir] != NULL)
 270     {
 271       /* Oh, oh.  We must close this stream.  Get all remaining
 272          entries and store them as a list in the `content' member of
 273          the `struct dir_data' variable.  */
 274       size_t bufsize = 1024;
 275       char *buf = malloc (bufsize);
 276
 277       if (buf == NULL)
 278         result = -1;
 279       else
 280         {
 281           DIR *st = data->dirstreams[data->actdir]->stream;
 282           struct dirent64 *d;
 283           size_t actsize = 0;
 284
 285           while ((d = __readdir64 (st)) != NULL)
 286             {
 287               size_t this_len = NAMLEN (d);
 288               if (actsize + this_len + 2 >= bufsize)
 289                 {
 290                   char *newp;
 291                   bufsize += MAX (1024, 2 * this_len);
 292                   newp = (char *) realloc (buf, bufsize);
 293                   if (newp == NULL)
 294                     {
 295                       /* No more memory.  */
 296                       int save_err = errno;
 297                       free (buf);
 298                       __set_errno (save_err);
 299                       return -1;
 300                     }
 301                   buf = newp;
 302                 }
 303
 304               *((char *) __mempcpy (buf + actsize, d->d_name, this_len))
 305                 = '\0';
 306               actsize += this_len + 1;
 307             }
 308
 309           /* Terminate the list with an additional NUL byte.  */
 310           buf[actsize++] = '\0';
 311
 312           /* Shrink the buffer to what we actually need.  */
 313           data->dirstreams[data->actdir]->content = realloc (buf, actsize);
 314           if (data->dirstreams[data->actdir]->content == NULL)
 315             {
 316               int save_err = errno;
 317               free (buf);
 318               __set_errno (save_err);
 319               result = -1;
 320             }
 321           else
 322             {
 323               __closedir (st);
 324               data->dirstreams[data->actdir]->stream = NULL;
 325               data->dirstreams[data->actdir]->streamfd = -1;
 326               data->dirstreams[data->actdir] = NULL;
 327             }
 328         }
 329     }
 330
 331   /* Open the new stream.  */
 332   if (result == 0)
 333     {
 334       assert (data->dirstreams[data->actdir] == NULL);
 335
 336       if (dfdp != NULL && *dfdp != -1)
 337         {
 338           int fd = __openat64_nocancel (*dfdp, data->dirbuf + data->ftw.base,
 339                                         O_RDONLY | O_DIRECTORY | O_NDELAY);
 340           dirp->stream = NULL;
 341           if (fd != -1 && (dirp->stream = __fdopendir (fd)) == NULL)
 342             __close_nocancel_nostatus (fd);
 343         }
 344       else
 345         {
 346           const char *name;
 347
 348           if (data->flags & FTW_CHDIR)
 349             {
 350               name = data->dirbuf + data->ftw.base;
 351               if (name[0] == '\0')
 352                 name = ".";
 353             }
 354           else
 355             name = data->dirbuf;
 356
 357           dirp->stream = __opendir (name);
 358         }
 359
 360       if (dirp->stream == NULL)
 361         result = -1;
 362       else
 363         {
 364           dirp->streamfd = __dirfd (dirp->stream);
 365           dirp->content = NULL;
 366           data->dirstreams[data->actdir] = dirp;
 367
 368           if (++data->actdir == data->maxdir)
 369             data->actdir = 0;
 370         }
 371     }
 372
 373   return result;
 374 }
 375
 376
 377 static int
 378 process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
 379                size_t namlen, int d_type)
 380 {
 381   struct STRUCT_STAT st;
 382   int result = 0;
 383   int flag = 0;
 384   size_t new_buflen;
 385
 386   if (name[0] == '.' && (name[1] == '\0'
 387                          || (name[1] == '.' && name[2] == '\0')))
 388     /* Don't process the "." and ".." entries.  */
 389     return 0;
 390
 391   new_buflen = data->ftw.base + namlen + 2;
 392   if (data->dirbufsize < new_buflen)
 393     {
 394       /* Enlarge the buffer.  */
 395       char *newp;
 396
 397       data->dirbufsize = 2 * new_buflen;
 398       newp = (char *) realloc (data->dirbuf, data->dirbufsize);
 399       if (newp == NULL)
 400         return -1;
 401       data->dirbuf = newp;
 402     }
 403
 404   *((char *) __mempcpy (data->dirbuf + data->ftw.base, name, namlen)) = '\0';
 405
 406   int statres;
 407   if (dir->streamfd != -1)
 408     statres = FSTATAT (dir->streamfd, name, &st,
 409                        (data->flags & FTW_PHYS) ? AT_SYMLINK_NOFOLLOW : 0);
 410   else
 411     {
 412       if ((data->flags & FTW_CHDIR) == 0)
 413         name = data->dirbuf;
 414
 415       statres = ((data->flags & FTW_PHYS)
 416                  ? LSTAT (name, &st)
 417                  : STAT (name, &st));
 418     }
 419
 420   if (statres < 0)
 421     {
 422       if (errno != EACCES && errno != ENOENT)
 423         result = -1;
 424       else if (data->flags & FTW_PHYS)
 425         flag = FTW_NS;
 426       else
 427         {
 428           /* Old code left ST undefined for dangling DT_LNK without
 429              FTW_PHYS set; a clarification at the POSIX level suggests
 430              it should contain information about the link (ala lstat).
 431              We do our best to fill in what data we can.  */
 432           if (dir->streamfd != -1)
 433             statres = FSTATAT (dir->streamfd, name, &st,
 434                                AT_SYMLINK_NOFOLLOW);
 435           else
 436             statres = LSTAT (name, &st);
 437           if (statres == 0 && S_ISLNK (st.st_mode))
 438             flag = FTW_SLN;
 439           else
 440             flag = FTW_NS;
 441         }
 442     }
 443   else
 444     {
 445       if (S_ISDIR (st.st_mode))
 446         flag = FTW_D;
 447       else if (S_ISLNK (st.st_mode))
 448         flag = FTW_SL;
 449       else
 450         flag = FTW_F;
 451     }
 452
 453   if (result == 0
 454       && (flag == FTW_NS
 455           || !(data->flags & FTW_MOUNT) || st.st_dev == data->dev))
 456     {
 457       if (flag == FTW_D)
 458         {
 459           if ((data->flags & FTW_PHYS)
 460               || (!find_object (data, &st)
 461                   /* Remember the object.  */
 462                   && (result = add_object (data, &st)) == 0))
 463             result = ftw_dir (data, &st, dir);
 464         }
 465       else
 466         result = (*data->func) (data->dirbuf, &st, data->cvt_arr[flag],
 467                                 &data->ftw);
 468     }
 469
 470   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SUBTREE)
 471     result = 0;
 472
 473   return result;
 474 }
 475
 476
 477 static int
 478 __attribute ((noinline))
 479 ftw_dir (struct ftw_data *data, struct STRUCT_STAT *st, struct dir_data *old_dir)
 480 {
 481   struct dir_data dir;
 482   struct dirent64 *d;
 483   int previous_base = data->ftw.base;
 484   int result;
 485   char *startp;
 486
 487   /* Open the stream for this directory.  This might require that
 488      another stream has to be closed.  */
 489   result = open_dir_stream (old_dir == NULL ? NULL : &old_dir->streamfd,
 490                             data, &dir);
 491   if (result != 0)
 492     {
 493       if (errno == EACCES)
 494         /* We cannot read the directory.  Signal this with a special flag.  */
 495         result = (*data->func) (data->dirbuf, st, FTW_DNR, &data->ftw);
 496
 497       return result;
 498     }
 499
 500   /* First, report the directory (if not depth-first).  */
 501   if (!(data->flags & FTW_DEPTH))
 502     {
 503       result = (*data->func) (data->dirbuf, st, FTW_D, &data->ftw);
 504       if (result != 0)
 505         {
 506           int save_err;
 507 fail:
 508           save_err = errno;
 509           __closedir (dir.stream);
 510           dir.streamfd = -1;
 511           __set_errno (save_err);
 512
 513           if (data->actdir-- == 0)
 514             data->actdir = data->maxdir - 1;
 515           data->dirstreams[data->actdir] = NULL;
 516           return result;
 517         }
 518     }
 519
 520   /* If necessary, change to this directory.  */
 521   if (data->flags & FTW_CHDIR)
 522     {
 523       if (__fchdir (__dirfd (dir.stream)) < 0)
 524         {
 525           result = -1;
 526           goto fail;
 527         }
 528     }
 529
 530   /* Next, update the `struct FTW' information.  */
 531   ++data->ftw.level;
 532   startp = __rawmemchr (data->dirbuf, '\0');
 533   /* There always must be a directory name.  */
 534   assert (startp != data->dirbuf);
 535   if (startp[-1] != '/')
 536     *startp++ = '/';
 537   data->ftw.base = startp - data->dirbuf;
 538
 539   while (dir.stream != NULL && (d = __readdir64 (dir.stream)) != NULL)
 540     {
 541       int d_type = DT_UNKNOWN;
 542 #ifdef _DIRENT_HAVE_D_TYPE
 543       d_type = d->d_type;
 544 #endif
 545       result = process_entry (data, &dir, d->d_name, NAMLEN (d), d_type);
 546       if (result != 0)
 547         break;
 548     }
 549
 550   if (dir.stream != NULL)
 551     {
 552       /* The stream is still open.  I.e., we did not need more
 553          descriptors.  Simply close the stream now.  */
 554       int save_err = errno;
 555
 556       assert (dir.content == NULL);
 557
 558       __closedir (dir.stream);
 559       dir.streamfd = -1;
 560       __set_errno (save_err);
 561
 562       if (data->actdir-- == 0)
 563         data->actdir = data->maxdir - 1;
 564       data->dirstreams[data->actdir] = NULL;
 565     }
 566   else
 567     {
 568       int save_err;
 569       char *runp = dir.content;
 570
 571       while (result == 0 && *runp != '\0')
 572         {
 573           char *endp = strchr (runp, '\0');
 574
 575           // XXX Should store the d_type values as well?!
 576           result = process_entry (data, &dir, runp, endp - runp, DT_UNKNOWN);
 577
 578           runp = endp + 1;
 579         }
 580
 581       save_err = errno;
 582       free (dir.content);
 583       __set_errno (save_err);
 584     }
 585
 586   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SIBLINGS)
 587     result = 0;
 588
 589   /* Prepare the return, revert the `struct FTW' information.  */
 590   data->dirbuf[data->ftw.base - 1] = '\0';
 591   --data->ftw.level;
 592   data->ftw.base = previous_base;
 593
 594   /* Finally, if we process depth-first report the directory.  */
 595   if (result == 0 && (data->flags & FTW_DEPTH))
 596     result = (*data->func) (data->dirbuf, st, FTW_DP, &data->ftw);
 597
 598   if (old_dir
 599       && (data->flags & FTW_CHDIR)
 600       && (result == 0
 601           || ((data->flags & FTW_ACTIONRETVAL)
 602               && (result != -1 && result != FTW_STOP))))
 603     {
 604       /* Change back to the parent directory.  */
 605       int done = 0;
 606       if (old_dir->stream != NULL)
 607         if (__fchdir (__dirfd (old_dir->stream)) == 0)
 608           done = 1;
 609
 610       if (!done)
 611         {
 612           if (data->ftw.base == 1)
 613             {
 614               if (__chdir ("/") < 0)
 615                 result = -1;
 616             }
 617           else
 618             if (__chdir ("..") < 0)
 619               result = -1;
 620         }
 621     }
 622
 623   return result;
 624 }
 625
 626
 627 static int
 628 __attribute ((noinline))
 629 ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 630              int flags)
 631 {
 632   struct ftw_data data;
 633   struct STRUCT_STAT st;
 634   int result = 0;
 635   int save_err;
 636   int cwdfd = -1;
 637   char *cwd = NULL;
 638   char *cp;
 639
 640   /* First make sure the parameters are reasonable.  */
 641   if (dir[0] == '\0')
 642     {
 643       __set_errno (ENOENT);
 644       return -1;
 645     }
 646
 647   data.maxdir = descriptors < 1 ? 1 : descriptors;
 648   data.actdir = 0;
 649   /* PATH_MAX is always defined when we get here.  */
 650   data.dirbufsize = MAX (2 * strlen (dir), PATH_MAX);
 651   data.dirstreams = malloc (data.maxdir * sizeof (struct dir_data *)
 652                             + data.dirbufsize);
 653   if (data.dirstreams == NULL)
 654     return -1;
 655
 656   memset (data.dirstreams, '\0', data.maxdir * sizeof (struct dir_data *));
 657
 658   data.dirbuf = (char *) data.dirstreams
 659                 + data.maxdir * sizeof (struct dir_data *);
 660   cp = __stpcpy (data.dirbuf, dir);
 661   /* Strip trailing slashes.  */
 662   while (cp > data.dirbuf + 1 && cp[-1] == '/')
 663     --cp;
 664   *cp = '\0';
 665
 666   data.ftw.level = 0;
 667
 668   /* Find basename.  */
 669   while (cp > data.dirbuf && cp[-1] != '/')
 670     --cp;
 671   data.ftw.base = cp - data.dirbuf;
 672
 673   data.flags = flags;
 674
 675   /* This assignment might seem to be strange but it is what we want.
 676      The trick is that the first three arguments to the `ftw' and
 677      `nftw' callback functions are equal.  Therefore we can call in
 678      every case the callback using the format of the `nftw' version
 679      and get the correct result since the stack layout for a function
 680      call in C allows this.  */
 681   data.func = (NFTW_FUNC_T) func;
 682
 683   /* Since we internally use the complete set of FTW_* values we need
 684      to reduce the value range before calling a `ftw' callback.  */
 685   data.cvt_arr = is_nftw ? nftw_arr : ftw_arr;
 686
 687   /* No object known so far.  */
 688   data.known_objects = NULL;
 689
 690   /* Now go to the directory containing the initial file/directory.  */
 691   if (flags & FTW_CHDIR)
 692     {
 693       /* We have to be able to go back to the current working
 694          directory.  The best way to do this is to use a file
 695          descriptor.  */
 696       cwdfd = __open (".", O_RDONLY | O_DIRECTORY);
 697       if (cwdfd == -1)
 698         {
 699           /* Try getting the directory name.  This can be needed if
 700              the current directory is executable but not readable.  */
 701           if (errno == EACCES)
 702             /* GNU extension ahead.  */
 703             cwd =  __getcwd (NULL, 0);
 704
 705           if (cwd == NULL)
 706             goto out_fail;
 707         }
 708       else if (data.maxdir > 1)
 709         /* Account for the file descriptor we use here.  */
 710         --data.maxdir;
 711
 712       if (data.ftw.base > 0)
 713         {
 714           /* Change to the directory the file is in.  In data.dirbuf
 715              we have a writable copy of the file name.  Just NUL
 716              terminate it for now and change the directory.  */
 717           if (data.ftw.base == 1)
 718             /* I.e., the file is in the root directory.  */
 719             result = __chdir ("/");
 720           else
 721             {
 722               char ch = data.dirbuf[data.ftw.base - 1];
 723               data.dirbuf[data.ftw.base - 1] = '\0';
 724               result = __chdir (data.dirbuf);
 725               data.dirbuf[data.ftw.base - 1] = ch;
 726             }
 727         }
 728     }
 729
 730   /* Get stat info for start directory.  */
 731   if (result == 0)
 732     {
 733       const char *name;
 734
 735       if (data.flags & FTW_CHDIR)
 736         {
 737           name = data.dirbuf + data.ftw.base;
 738           if (name[0] == '\0')
 739             name = ".";
 740         }
 741       else
 742         name = data.dirbuf;
 743
 744       if (((flags & FTW_PHYS)
 745            ? LSTAT (name, &st)
 746            : STAT (name, &st)) < 0)
 747         {
 748           if (!(flags & FTW_PHYS)
 749               && errno == ENOENT
 750               && LSTAT (name, &st) == 0
 751               && S_ISLNK (st.st_mode))
 752             result = (*data.func) (data.dirbuf, &st, data.cvt_arr[FTW_SLN],
 753                                    &data.ftw);
 754           else
 755             /* No need to call the callback since we cannot say anything
 756                about the object.  */
 757             result = -1;
 758         }
 759       else
 760         {
 761           if (S_ISDIR (st.st_mode))
 762             {
 763               /* Remember the device of the initial directory in case
 764                  FTW_MOUNT is given.  */
 765               data.dev = st.st_dev;
 766
 767               /* We know this directory now.  */
 768               if (!(flags & FTW_PHYS))
 769                 result = add_object (&data, &st);
 770
 771               if (result == 0)
 772                 result = ftw_dir (&data, &st, NULL);
 773             }
 774           else
 775             {
 776               int flag = S_ISLNK (st.st_mode) ? FTW_SL : FTW_F;
 777
 778               result = (*data.func) (data.dirbuf, &st, data.cvt_arr[flag],
 779                                      &data.ftw);
 780             }
 781         }
 782
 783       if ((flags & FTW_ACTIONRETVAL)
 784           && (result == FTW_SKIP_SUBTREE || result == FTW_SKIP_SIBLINGS))
 785         result = 0;
 786     }
 787
 788   /* Return to the start directory (if necessary).  */
 789   if (cwdfd != -1)
 790     {
 791       int save_err = errno;
 792       __fchdir (cwdfd);
 793       __close_nocancel_nostatus (cwdfd);
 794       __set_errno (save_err);
 795     }
 796   else if (cwd != NULL)
 797     {
 798       int save_err = errno;
 799       __chdir (cwd);
 800       free (cwd);
 801       __set_errno (save_err);
 802     }
 803
 804   /* Free all memory.  */
 805  out_fail:
 806   save_err = errno;
 807   __tdestroy (data.known_objects, free);
 808   free (data.dirstreams);
 809   __set_errno (save_err);
 810
 811   return result;
 812 }
 813
 814
 815
 816 /* Entry points.  */
 817
 818 int
 819 FTW_NAME (const char *path, FTW_FUNC_T func, int descriptors)
 820 {
 821   return ftw_startup (path, 0, func, descriptors, 0);
 822 }
 823
 824 #ifndef NFTW_OLD_NAME
 825 int
 826 NFTW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 827 {
 828   return ftw_startup (path, 1, func, descriptors, flags);
 829 }
 830 #else
 831
 832 # include <shlib-compat.h>
 833
 834 int NFTW_NEW_NAME (const char *, NFTW_FUNC_T, int, int);
 835
 836 int
 837 NFTW_NEW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 838 {
 839   if (flags
 840       & ~(FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH | FTW_ACTIONRETVAL))
 841     {
 842       __set_errno (EINVAL);
 843       return -1;
 844     }
 845   return ftw_startup (path, 1, func, descriptors, flags);
 846 }
 847 versioned_symbol (libc, NFTW_NEW_NAME, NFTW_NAME, GLIBC_2_3_3);
 848
 849 # if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_3_3)
 850
 851 /* Older nftw* version just ignored all unknown flags.  */
 852
 853 int NFTW_OLD_NAME (const char *, NFTW_FUNC_T, int, int);
 854
 855 int
 856 attribute_compat_text_section
 857 NFTW_OLD_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 858 {
 859   flags &= (FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH);
 860   return ftw_startup (path, 1, func, descriptors, flags);
 861 }
 862
 863 compat_symbol (libc, NFTW_OLD_NAME, NFTW_NAME, GLIBC_2_1);
 864 # endif
 865 #endif /* NFTW_OLD_NAME  */