io/ftw.c

   1 /* File tree walker functions.
   2    Copyright (C) 1996-2017 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    <http://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 internal_function
 113 # define internal_function /* empty */
 114 # undef dirent64
 115 # define dirent64 dirent
 116 # undef MAX
 117 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 118 #endif
 119
 120 /* Arrange to make lstat calls go through the wrapper function
 121    on systems with an lstat function that does not dereference symlinks
 122    that are specified with a trailing slash.  */
 123 #if ! _LIBC && ! LSTAT_FOLLOWS_SLASHED_SYMLINK
 124 int rpl_lstat (const char *, struct stat *);
 125 # undef lstat
 126 # define lstat(Name, Stat_buf) rpl_lstat(Name, Stat_buf)
 127 #endif
 128
 129 #ifndef __set_errno
 130 # define __set_errno(Val) errno = (Val)
 131 #endif
 132
 133 /* Support for the LFS API version.  */
 134 #ifndef FTW_NAME
 135 # define FTW_NAME ftw
 136 # define NFTW_NAME nftw
 137 # define NFTW_OLD_NAME __old_nftw
 138 # define NFTW_NEW_NAME __new_nftw
 139 # define INO_T ino_t
 140 # define STAT stat
 141 # ifdef _LIBC
 142 #  define LXSTAT __lxstat
 143 #  define XSTAT __xstat
 144 #  define FXSTATAT __fxstatat
 145 # else
 146 #  define LXSTAT(V,f,sb) lstat (f,sb)
 147 #  define XSTAT(V,f,sb) stat (f,sb)
 148 #  define FXSTATAT(V,d,f,sb,m) fstatat (d, f, sb, m)
 149 # endif
 150 # define FTW_FUNC_T __ftw_func_t
 151 # define NFTW_FUNC_T __nftw_func_t
 152 #endif
 153
 154 /* We define PATH_MAX if the system does not provide a definition.
 155    This does not artificially limit any operation.  PATH_MAX is simply
 156    used as a guesstimate for the expected maximal path length.
 157    Buffers will be enlarged if necessary.  */
 158 #ifndef PATH_MAX
 159 # define PATH_MAX 1024
 160 #endif
 161
 162 struct dir_data
 163 {
 164   DIR *stream;
 165   int streamfd;
 166   char *content;
 167 };
 168
 169 struct known_object
 170 {
 171   dev_t dev;
 172   INO_T ino;
 173 };
 174
 175 struct ftw_data
 176 {
 177   /* Array with pointers to open directory streams.  */
 178   struct dir_data **dirstreams;
 179   size_t actdir;
 180   size_t maxdir;
 181
 182   /* Buffer containing name of currently processed object.  */
 183   char *dirbuf;
 184   size_t dirbufsize;
 185
 186   /* Passed as fourth argument to `nftw' callback.  The `base' member
 187      tracks the content of the `dirbuf'.  */
 188   struct FTW ftw;
 189
 190   /* Flags passed to `nftw' function.  0 for `ftw'.  */
 191   int flags;
 192
 193   /* Conversion array for flag values.  It is the identity mapping for
 194      `nftw' calls, otherwise it maps the values to those known by
 195      `ftw'.  */
 196   const int *cvt_arr;
 197
 198   /* Callback function.  We always use the `nftw' form.  */
 199   NFTW_FUNC_T func;
 200
 201   /* Device of starting point.  Needed for FTW_MOUNT.  */
 202   dev_t dev;
 203
 204   /* Data structure for keeping fingerprints of already processed
 205      object.  This is needed when not using FTW_PHYS.  */
 206   void *known_objects;
 207 };
 208
 209
 210 /* Internally we use the FTW_* constants used for `nftw'.  When invoked
 211    as `ftw', map each flag to the subset of values used by `ftw'.  */
 212 static const int nftw_arr[] =
 213 {
 214   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_SL, FTW_DP, FTW_SLN
 215 };
 216
 217 static const int ftw_arr[] =
 218 {
 219   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_F, FTW_D, FTW_NS
 220 };
 221
 222
 223 /* Forward declarations of local functions.  */
 224 static int ftw_dir (struct ftw_data *data, struct STAT *st,
 225                     struct dir_data *old_dir) internal_function;
 226
 227
 228 static int
 229 object_compare (const void *p1, const void *p2)
 230 {
 231   /* We don't need a sophisticated and useful comparison.  We are only
 232      interested in equality.  However, we must be careful not to
 233      accidentally compare `holes' in the structure.  */
 234   const struct known_object *kp1 = p1, *kp2 = p2;
 235   int cmp1;
 236   cmp1 = (kp1->ino > kp2->ino) - (kp1->ino < kp2->ino);
 237   if (cmp1 != 0)
 238     return cmp1;
 239   return (kp1->dev > kp2->dev) - (kp1->dev < kp2->dev);
 240 }
 241
 242
 243 static int
 244 add_object (struct ftw_data *data, struct STAT *st)
 245 {
 246   struct known_object *newp = malloc (sizeof (struct known_object));
 247   if (newp == NULL)
 248     return -1;
 249   newp->dev = st->st_dev;
 250   newp->ino = st->st_ino;
 251   return __tsearch (newp, &data->known_objects, object_compare) ? 0 : -1;
 252 }
 253
 254
 255 static inline int
 256 find_object (struct ftw_data *data, struct STAT *st)
 257 {
 258   struct known_object obj;
 259   obj.dev = st->st_dev;
 260   obj.ino = st->st_ino;
 261   return __tfind (&obj, &data->known_objects, object_compare) != NULL;
 262 }
 263
 264
 265 static inline int
 266 __attribute ((always_inline))
 267 open_dir_stream (int *dfdp, struct ftw_data *data, struct dir_data *dirp)
 268 {
 269   int result = 0;
 270
 271   if (data->dirstreams[data->actdir] != NULL)
 272     {
 273       /* Oh, oh.  We must close this stream.  Get all remaining
 274          entries and store them as a list in the `content' member of
 275          the `struct dir_data' variable.  */
 276       size_t bufsize = 1024;
 277       char *buf = malloc (bufsize);
 278
 279       if (buf == NULL)
 280         result = -1;
 281       else
 282         {
 283           DIR *st = data->dirstreams[data->actdir]->stream;
 284           struct dirent64 *d;
 285           size_t actsize = 0;
 286
 287           while ((d = __readdir64 (st)) != NULL)
 288             {
 289               size_t this_len = NAMLEN (d);
 290               if (actsize + this_len + 2 >= bufsize)
 291                 {
 292                   char *newp;
 293                   bufsize += MAX (1024, 2 * this_len);
 294                   newp = (char *) realloc (buf, bufsize);
 295                   if (newp == NULL)
 296                     {
 297                       /* No more memory.  */
 298                       int save_err = errno;
 299                       free (buf);
 300                       __set_errno (save_err);
 301                       return -1;
 302                     }
 303                   buf = newp;
 304                 }
 305
 306               *((char *) __mempcpy (buf + actsize, d->d_name, this_len))
 307                 = '\0';
 308               actsize += this_len + 1;
 309             }
 310
 311           /* Terminate the list with an additional NUL byte.  */
 312           buf[actsize++] = '\0';
 313
 314           /* Shrink the buffer to what we actually need.  */
 315           data->dirstreams[data->actdir]->content = realloc (buf, actsize);
 316           if (data->dirstreams[data->actdir]->content == NULL)
 317             {
 318               int save_err = errno;
 319               free (buf);
 320               __set_errno (save_err);
 321               result = -1;
 322             }
 323           else
 324             {
 325               __closedir (st);
 326               data->dirstreams[data->actdir]->stream = NULL;
 327               data->dirstreams[data->actdir]->streamfd = -1;
 328               data->dirstreams[data->actdir] = NULL;
 329             }
 330         }
 331     }
 332
 333   /* Open the new stream.  */
 334   if (result == 0)
 335     {
 336       assert (data->dirstreams[data->actdir] == NULL);
 337
 338       if (dfdp != NULL && *dfdp != -1)
 339         {
 340           int fd = openat64_not_cancel_3 (*dfdp, data->dirbuf + data->ftw.base,
 341                                           O_RDONLY | O_DIRECTORY | O_NDELAY);
 342           dirp->stream = NULL;
 343           if (fd != -1 && (dirp->stream = __fdopendir (fd)) == NULL)
 344             close_not_cancel_no_status (fd);
 345         }
 346       else
 347         {
 348           const char *name;
 349
 350           if (data->flags & FTW_CHDIR)
 351             {
 352               name = data->dirbuf + data->ftw.base;
 353               if (name[0] == '\0')
 354                 name = ".";
 355             }
 356           else
 357             name = data->dirbuf;
 358
 359           dirp->stream = __opendir (name);
 360         }
 361
 362       if (dirp->stream == NULL)
 363         result = -1;
 364       else
 365         {
 366           dirp->streamfd = dirfd (dirp->stream);
 367           dirp->content = NULL;
 368           data->dirstreams[data->actdir] = dirp;
 369
 370           if (++data->actdir == data->maxdir)
 371             data->actdir = 0;
 372         }
 373     }
 374
 375   return result;
 376 }
 377
 378
 379 static int
 380 internal_function
 381 process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
 382                size_t namlen, int d_type)
 383 {
 384   struct STAT st;
 385   int result = 0;
 386   int flag = 0;
 387   size_t new_buflen;
 388
 389   if (name[0] == '.' && (name[1] == '\0'
 390                          || (name[1] == '.' && name[2] == '\0')))
 391     /* Don't process the "." and ".." entries.  */
 392     return 0;
 393
 394   new_buflen = data->ftw.base + namlen + 2;
 395   if (data->dirbufsize < new_buflen)
 396     {
 397       /* Enlarge the buffer.  */
 398       char *newp;
 399
 400       data->dirbufsize = 2 * new_buflen;
 401       newp = (char *) realloc (data->dirbuf, data->dirbufsize);
 402       if (newp == NULL)
 403         return -1;
 404       data->dirbuf = newp;
 405     }
 406
 407   *((char *) __mempcpy (data->dirbuf + data->ftw.base, name, namlen)) = '\0';
 408
 409   int statres;
 410   if (dir->streamfd != -1)
 411     statres = FXSTATAT (_STAT_VER, dir->streamfd, name, &st,
 412                         (data->flags & FTW_PHYS) ? AT_SYMLINK_NOFOLLOW : 0);
 413   else
 414     {
 415       if ((data->flags & FTW_CHDIR) == 0)
 416         name = data->dirbuf;
 417
 418       statres = ((data->flags & FTW_PHYS)
 419                  ? LXSTAT (_STAT_VER, name, &st)
 420                  : XSTAT (_STAT_VER, name, &st));
 421     }
 422
 423   if (statres < 0)
 424     {
 425       if (errno != EACCES && errno != ENOENT)
 426         result = -1;
 427       else if (data->flags & FTW_PHYS)
 428         flag = FTW_NS;
 429       else if (d_type == DT_LNK)
 430         flag = FTW_SLN;
 431       else
 432         {
 433           if (dir->streamfd != -1)
 434             statres = FXSTATAT (_STAT_VER, dir->streamfd, name, &st,
 435                                 AT_SYMLINK_NOFOLLOW);
 436           else
 437             statres = LXSTAT (_STAT_VER, name, &st);
 438           if (statres == 0 && S_ISLNK (st.st_mode))
 439             flag = FTW_SLN;
 440           else
 441             flag = FTW_NS;
 442         }
 443     }
 444   else
 445     {
 446       if (S_ISDIR (st.st_mode))
 447         flag = FTW_D;
 448       else if (S_ISLNK (st.st_mode))
 449         flag = FTW_SL;
 450       else
 451         flag = FTW_F;
 452     }
 453
 454   if (result == 0
 455       && (flag == FTW_NS
 456           || !(data->flags & FTW_MOUNT) || st.st_dev == data->dev))
 457     {
 458       if (flag == FTW_D)
 459         {
 460           if ((data->flags & FTW_PHYS)
 461               || (!find_object (data, &st)
 462                   /* Remember the object.  */
 463                   && (result = add_object (data, &st)) == 0))
 464             result = ftw_dir (data, &st, dir);
 465         }
 466       else
 467         result = (*data->func) (data->dirbuf, &st, data->cvt_arr[flag],
 468                                 &data->ftw);
 469     }
 470
 471   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SUBTREE)
 472     result = 0;
 473
 474   return result;
 475 }
 476
 477
 478 static int
 479 __attribute ((noinline))
 480 internal_function
 481 ftw_dir (struct ftw_data *data, struct STAT *st, struct dir_data *old_dir)
 482 {
 483   struct dir_data dir;
 484   struct dirent64 *d;
 485   int previous_base = data->ftw.base;
 486   int result;
 487   char *startp;
 488
 489   /* Open the stream for this directory.  This might require that
 490      another stream has to be closed.  */
 491   result = open_dir_stream (old_dir == NULL ? NULL : &old_dir->streamfd,
 492                             data, &dir);
 493   if (result != 0)
 494     {
 495       if (errno == EACCES)
 496         /* We cannot read the directory.  Signal this with a special flag.  */
 497         result = (*data->func) (data->dirbuf, st, FTW_DNR, &data->ftw);
 498
 499       return result;
 500     }
 501
 502   /* First, report the directory (if not depth-first).  */
 503   if (!(data->flags & FTW_DEPTH))
 504     {
 505       result = (*data->func) (data->dirbuf, st, FTW_D, &data->ftw);
 506       if (result != 0)
 507         {
 508           int save_err;
 509 fail:
 510           save_err = errno;
 511           __closedir (dir.stream);
 512           dir.streamfd = -1;
 513           __set_errno (save_err);
 514
 515           if (data->actdir-- == 0)
 516             data->actdir = data->maxdir - 1;
 517           data->dirstreams[data->actdir] = NULL;
 518           return result;
 519         }
 520     }
 521
 522   /* If necessary, change to this directory.  */
 523   if (data->flags & FTW_CHDIR)
 524     {
 525       if (__fchdir (dirfd (dir.stream)) < 0)
 526         {
 527           result = -1;
 528           goto fail;
 529         }
 530     }
 531
 532   /* Next, update the `struct FTW' information.  */
 533   ++data->ftw.level;
 534   startp = __rawmemchr (data->dirbuf, '\0');
 535   /* There always must be a directory name.  */
 536   assert (startp != data->dirbuf);
 537   if (startp[-1] != '/')
 538     *startp++ = '/';
 539   data->ftw.base = startp - data->dirbuf;
 540
 541   while (dir.stream != NULL && (d = __readdir64 (dir.stream)) != NULL)
 542     {
 543       int d_type = DT_UNKNOWN;
 544 #ifdef _DIRENT_HAVE_D_TYPE
 545       d_type = d->d_type;
 546 #endif
 547       result = process_entry (data, &dir, d->d_name, NAMLEN (d), d_type);
 548       if (result != 0)
 549         break;
 550     }
 551
 552   if (dir.stream != NULL)
 553     {
 554       /* The stream is still open.  I.e., we did not need more
 555          descriptors.  Simply close the stream now.  */
 556       int save_err = errno;
 557
 558       assert (dir.content == NULL);
 559
 560       __closedir (dir.stream);
 561       dir.streamfd = -1;
 562       __set_errno (save_err);
 563
 564       if (data->actdir-- == 0)
 565         data->actdir = data->maxdir - 1;
 566       data->dirstreams[data->actdir] = NULL;
 567     }
 568   else
 569     {
 570       int save_err;
 571       char *runp = dir.content;
 572
 573       while (result == 0 && *runp != '\0')
 574         {
 575           char *endp = strchr (runp, '\0');
 576
 577           // XXX Should store the d_type values as well?!
 578           result = process_entry (data, &dir, runp, endp - runp, DT_UNKNOWN);
 579
 580           runp = endp + 1;
 581         }
 582
 583       save_err = errno;
 584       free (dir.content);
 585       __set_errno (save_err);
 586     }
 587
 588   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SIBLINGS)
 589     result = 0;
 590
 591   /* Prepare the return, revert the `struct FTW' information.  */
 592   data->dirbuf[data->ftw.base - 1] = '\0';
 593   --data->ftw.level;
 594   data->ftw.base = previous_base;
 595
 596   /* Finally, if we process depth-first report the directory.  */
 597   if (result == 0 && (data->flags & FTW_DEPTH))
 598     result = (*data->func) (data->dirbuf, st, FTW_DP, &data->ftw);
 599
 600   if (old_dir
 601       && (data->flags & FTW_CHDIR)
 602       && (result == 0
 603           || ((data->flags & FTW_ACTIONRETVAL)
 604               && (result != -1 && result != FTW_STOP))))
 605     {
 606       /* Change back to the parent directory.  */
 607       int done = 0;
 608       if (old_dir->stream != NULL)
 609         if (__fchdir (dirfd (old_dir->stream)) == 0)
 610           done = 1;
 611
 612       if (!done)
 613         {
 614           if (data->ftw.base == 1)
 615             {
 616               if (__chdir ("/") < 0)
 617                 result = -1;
 618             }
 619           else
 620             if (__chdir ("..") < 0)
 621               result = -1;
 622         }
 623     }
 624
 625   return result;
 626 }
 627
 628
 629 static int
 630 __attribute ((noinline))
 631 internal_function
 632 ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 633              int flags)
 634 {
 635   struct ftw_data data;
 636   struct STAT st;
 637   int result = 0;
 638   int save_err;
 639   int cwdfd = -1;
 640   char *cwd = NULL;
 641   char *cp;
 642
 643   /* First make sure the parameters are reasonable.  */
 644   if (dir[0] == '\0')
 645     {
 646       __set_errno (ENOENT);
 647       return -1;
 648     }
 649
 650   data.maxdir = descriptors < 1 ? 1 : descriptors;
 651   data.actdir = 0;
 652   data.dirstreams = (struct dir_data **) alloca (data.maxdir
 653                                                  * sizeof (struct dir_data *));
 654   memset (data.dirstreams, '\0', data.maxdir * sizeof (struct dir_data *));
 655
 656   /* PATH_MAX is always defined when we get here.  */
 657   data.dirbufsize = MAX (2 * strlen (dir), PATH_MAX);
 658   data.dirbuf = (char *) malloc (data.dirbufsize);
 659   if (data.dirbuf == NULL)
 660     return -1;
 661   cp = __stpcpy (data.dirbuf, dir);
 662   /* Strip trailing slashes.  */
 663   while (cp > data.dirbuf + 1 && cp[-1] == '/')
 664     --cp;
 665   *cp = '\0';
 666
 667   data.ftw.level = 0;
 668
 669   /* Find basename.  */
 670   while (cp > data.dirbuf && cp[-1] != '/')
 671     --cp;
 672   data.ftw.base = cp - data.dirbuf;
 673
 674   data.flags = flags;
 675
 676   /* This assignment might seem to be strange but it is what we want.
 677      The trick is that the first three arguments to the `ftw' and
 678      `nftw' callback functions are equal.  Therefore we can call in
 679      every case the callback using the format of the `nftw' version
 680      and get the correct result since the stack layout for a function
 681      call in C allows this.  */
 682   data.func = (NFTW_FUNC_T) func;
 683
 684   /* Since we internally use the complete set of FTW_* values we need
 685      to reduce the value range before calling a `ftw' callback.  */
 686   data.cvt_arr = is_nftw ? nftw_arr : ftw_arr;
 687
 688   /* No object known so far.  */
 689   data.known_objects = NULL;
 690
 691   /* Now go to the directory containing the initial file/directory.  */
 692   if (flags & FTW_CHDIR)
 693     {
 694       /* We have to be able to go back to the current working
 695          directory.  The best way to do this is to use a file
 696          descriptor.  */
 697       cwdfd = __open (".", O_RDONLY | O_DIRECTORY);
 698       if (cwdfd == -1)
 699         {
 700           /* Try getting the directory name.  This can be needed if
 701              the current directory is executable but not readable.  */
 702           if (errno == EACCES)
 703             /* GNU extension ahead.  */
 704             cwd =  __getcwd (NULL, 0);
 705
 706           if (cwd == NULL)
 707             goto out_fail;
 708         }
 709       else if (data.maxdir > 1)
 710         /* Account for the file descriptor we use here.  */
 711         --data.maxdir;
 712
 713       if (data.ftw.base > 0)
 714         {
 715           /* Change to the directory the file is in.  In data.dirbuf
 716              we have a writable copy of the file name.  Just NUL
 717              terminate it for now and change the directory.  */
 718           if (data.ftw.base == 1)
 719             /* I.e., the file is in the root directory.  */
 720             result = __chdir ("/");
 721           else
 722             {
 723               char ch = data.dirbuf[data.ftw.base - 1];
 724               data.dirbuf[data.ftw.base - 1] = '\0';
 725               result = __chdir (data.dirbuf);
 726               data.dirbuf[data.ftw.base - 1] = ch;
 727             }
 728         }
 729     }
 730
 731   /* Get stat info for start directory.  */
 732   if (result == 0)
 733     {
 734       const char *name;
 735
 736       if (data.flags & FTW_CHDIR)
 737         {
 738           name = data.dirbuf + data.ftw.base;
 739           if (name[0] == '\0')
 740             name = ".";
 741         }
 742       else
 743         name = data.dirbuf;
 744
 745       if (((flags & FTW_PHYS)
 746            ? LXSTAT (_STAT_VER, name, &st)
 747            : XSTAT (_STAT_VER, name, &st)) < 0)
 748         {
 749           if (!(flags & FTW_PHYS)
 750               && errno == ENOENT
 751               && LXSTAT (_STAT_VER, name, &st) == 0
 752               && S_ISLNK (st.st_mode))
 753             result = (*data.func) (data.dirbuf, &st, data.cvt_arr[FTW_SLN],
 754                                    &data.ftw);
 755           else
 756             /* No need to call the callback since we cannot say anything
 757                about the object.  */
 758             result = -1;
 759         }
 760       else
 761         {
 762           if (S_ISDIR (st.st_mode))
 763             {
 764               /* Remember the device of the initial directory in case
 765                  FTW_MOUNT is given.  */
 766               data.dev = st.st_dev;
 767
 768               /* We know this directory now.  */
 769               if (!(flags & FTW_PHYS))
 770                 result = add_object (&data, &st);
 771
 772               if (result == 0)
 773                 result = ftw_dir (&data, &st, NULL);
 774             }
 775           else
 776             {
 777               int flag = S_ISLNK (st.st_mode) ? FTW_SL : FTW_F;
 778
 779               result = (*data.func) (data.dirbuf, &st, data.cvt_arr[flag],
 780                                      &data.ftw);
 781             }
 782         }
 783
 784       if ((flags & FTW_ACTIONRETVAL)
 785           && (result == FTW_SKIP_SUBTREE || result == FTW_SKIP_SIBLINGS))
 786         result = 0;
 787     }
 788
 789   /* Return to the start directory (if necessary).  */
 790   if (cwdfd != -1)
 791     {
 792       int save_err = errno;
 793       __fchdir (cwdfd);
 794       close_not_cancel_no_status (cwdfd);
 795       __set_errno (save_err);
 796     }
 797   else if (cwd != NULL)
 798     {
 799       int save_err = errno;
 800       __chdir (cwd);
 801       free (cwd);
 802       __set_errno (save_err);
 803     }
 804
 805   /* Free all memory.  */
 806  out_fail:
 807   save_err = errno;
 808   __tdestroy (data.known_objects, free);
 809   free (data.dirbuf);
 810   __set_errno (save_err);
 811
 812   return result;
 813 }
 814
 815
 816
 817 /* Entry points.  */
 818
 819 int
 820 FTW_NAME (const char *path, FTW_FUNC_T func, int descriptors)
 821 {
 822   return ftw_startup (path, 0, func, descriptors, 0);
 823 }
 824
 825 #ifndef _LIBC
 826 int
 827 NFTW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 828 {
 829   return ftw_startup (path, 1, func, descriptors, flags);
 830 }
 831 #else
 832
 833 # include <shlib-compat.h>
 834
 835 int NFTW_NEW_NAME (const char *, NFTW_FUNC_T, int, int);
 836
 837 int
 838 NFTW_NEW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 839 {
 840   if (flags
 841       & ~(FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH | FTW_ACTIONRETVAL))
 842     {
 843       __set_errno (EINVAL);
 844       return -1;
 845     }
 846   return ftw_startup (path, 1, func, descriptors, flags);
 847 }
 848
 849 versioned_symbol (libc, NFTW_NEW_NAME, NFTW_NAME, GLIBC_2_3_3);
 850
 851 # if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_3_3)
 852
 853 /* Older nftw* version just ignored all unknown flags.  */
 854
 855 int NFTW_OLD_NAME (const char *, NFTW_FUNC_T, int, int);
 856
 857 int
 858 attribute_compat_text_section
 859 NFTW_OLD_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 860 {
 861   flags &= (FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH);
 862   return ftw_startup (path, 1, func, descriptors, flags);
 863 }
 864
 865 compat_symbol (libc, NFTW_OLD_NAME, NFTW_NAME, GLIBC_2_1);
 866 # endif
 867 #endif