io/ftw.c

   1 /* File tree walker functions.
   2    Copyright (C) 1996-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifdef HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22
  23 #if __GNUC__
  24 # define alloca __builtin_alloca
  25 #else
  26 # if HAVE_ALLOCA_H
  27 #  include <alloca.h>
  28 # else
  29 #  ifdef _AIX
  30  #  pragma alloca
  31 #  else
  32 char *alloca ();
  33 #  endif
  34 # endif
  35 #endif
  36
  37 #ifdef _LIBC
  38 # include <dirent.h>
  39 # define NAMLEN(dirent) _D_EXACT_NAMLEN (dirent)
  40 #else
  41 # if HAVE_DIRENT_H
  42 #  include <dirent.h>
  43 #  define NAMLEN(dirent) strlen ((dirent)->d_name)
  44 # else
  45 #  define dirent direct
  46 #  define NAMLEN(dirent) (dirent)->d_namlen
  47 #  if HAVE_SYS_NDIR_H
  48 #   include <sys/ndir.h>
  49 #  endif
  50 #  if HAVE_SYS_DIR_H
  51 #   include <sys/dir.h>
  52 #  endif
  53 #  if HAVE_NDIR_H
  54 #   include <ndir.h>
  55 #  endif
  56 # endif
  57 #endif
  58
  59 #include <errno.h>
  60 #include <fcntl.h>
  61 #include <ftw.h>
  62 #include <limits.h>
  63 #include <search.h>
  64 #include <stdlib.h>
  65 #include <string.h>
  66 #include <unistd.h>
  67 #include <not-cancel.h>
  68 #include <sys/param.h>
  69 #ifdef _LIBC
  70 # include <include/sys/stat.h>
  71 #else
  72 # include <sys/stat.h>
  73 #endif
  74
  75 #if ! _LIBC && !HAVE_DECL_STPCPY && !defined stpcpy
  76 char *stpcpy ();
  77 #endif
  78
  79 #if ! _LIBC && ! defined HAVE_MEMPCPY && ! defined mempcpy
  80 /* Be CAREFUL that there are no side effects in N.  */
  81 # define mempcpy(D, S, N) ((void *) ((char *) memcpy (D, S, N) + (N)))
  82 #endif
  83
  84 /* #define NDEBUG 1 */
  85 #include <assert.h>
  86
  87 #ifndef _LIBC
  88 # undef __chdir
  89 # define __chdir chdir
  90 # undef __closedir
  91 # define __closedir closedir
  92 # undef __fchdir
  93 # define __fchdir fchdir
  94 # undef __getcwd
  95 # define __getcwd(P, N) xgetcwd ()
  96 extern char *xgetcwd (void);
  97 # undef __mempcpy
  98 # define __mempcpy mempcpy
  99 # undef __opendir
 100 # define __opendir opendir
 101 # undef __readdir64
 102 # define __readdir64 readdir
 103 # undef __stpcpy
 104 # define __stpcpy stpcpy
 105 # undef __tdestroy
 106 # define __tdestroy tdestroy
 107 # undef __tfind
 108 # define __tfind tfind
 109 # undef __tsearch
 110 # define __tsearch tsearch
 111 # undef dirent64
 112 # define dirent64 dirent
 113 # undef MAX
 114 # define MAX(a, b) ((a) > (b) ? (a) : (b))
 115 #endif
 116
 117 /* Arrange to make lstat calls go through the wrapper function
 118    on systems with an lstat function that does not dereference symlinks
 119    that are specified with a trailing slash.  */
 120 #if ! _LIBC && ! LSTAT_FOLLOWS_SLASHED_SYMLINK
 121 int rpl_lstat (const char *, struct stat *);
 122 # undef lstat
 123 # define lstat(Name, Stat_buf) rpl_lstat(Name, Stat_buf)
 124 #endif
 125
 126 #ifndef __set_errno
 127 # define __set_errno(Val) errno = (Val)
 128 #endif
 129
 130 /* Support for the LFS API version.  */
 131 #ifndef FTW_NAME
 132 # define FTW_NAME ftw
 133 # define NFTW_NAME nftw
 134 # define NFTW_OLD_NAME __old_nftw
 135 # define NFTW_NEW_NAME __new_nftw
 136 # define INO_T ino_t
 137 # define STRUCT_STAT stat
 138 # ifdef _LIBC
 139 #  define LSTAT __lstat
 140 #  define STAT __stat
 141 #  define FSTATAT __fstatat
 142 # else
 143 #  define LSTAT lstat
 144 #  define XTAT stat
 145 #  define FSTATAT fstatat
 146 # endif
 147 # define FTW_FUNC_T __ftw_func_t
 148 # define NFTW_FUNC_T __nftw_func_t
 149 #endif
 150
 151 /* We define PATH_MAX if the system does not provide a definition.
 152    This does not artificially limit any operation.  PATH_MAX is simply
 153    used as a guesstimate for the expected maximal path length.
 154    Buffers will be enlarged if necessary.  */
 155 #ifndef PATH_MAX
 156 # define PATH_MAX 1024
 157 #endif
 158
 159 struct dir_data
 160 {
 161   DIR *stream;
 162   int streamfd;
 163   char *content;
 164 };
 165
 166 struct known_object
 167 {
 168   dev_t dev;
 169   INO_T ino;
 170 };
 171
 172 struct ftw_data
 173 {
 174   /* Array with pointers to open directory streams.  */
 175   struct dir_data **dirstreams;
 176   size_t actdir;
 177   size_t maxdir;
 178
 179   /* Buffer containing name of currently processed object.  */
 180   char *dirbuf;
 181   size_t dirbufsize;
 182
 183   /* Passed as fourth argument to `nftw' callback.  The `base' member
 184      tracks the content of the `dirbuf'.  */
 185   struct FTW ftw;
 186
 187   /* Flags passed to `nftw' function.  0 for `ftw'.  */
 188   int flags;
 189
 190   /* Conversion array for flag values.  It is the identity mapping for
 191      `nftw' calls, otherwise it maps the values to those known by
 192      `ftw'.  */
 193   const int *cvt_arr;
 194
 195   /* Callback function.  We always use the `nftw' form.  */
 196   NFTW_FUNC_T func;
 197
 198   /* Device of starting point.  Needed for FTW_MOUNT.  */
 199   dev_t dev;
 200
 201   /* Data structure for keeping fingerprints of already processed
 202      object.  This is needed when not using FTW_PHYS.  */
 203   void *known_objects;
 204 };
 205
 206 static bool
 207 ftw_allocate (struct ftw_data *data, size_t newsize)
 208 {
 209   void *newp = realloc (data->dirstreams, data->maxdir
 210                                           * sizeof (struct dir_data *)
 211                                           + newsize);
 212   if (newp == NULL)
 213     return false;
 214   data->dirstreams = newp;
 215   data->dirbufsize = newsize;
 216   data->dirbuf = (char *) data->dirstreams
 217                  + data->maxdir * sizeof (struct dir_data *);
 218   return true;
 219 }
 220
 221 /* Internally we use the FTW_* constants used for `nftw'.  When invoked
 222    as `ftw', map each flag to the subset of values used by `ftw'.  */
 223 static const int nftw_arr[] =
 224 {
 225   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_SL, FTW_DP, FTW_SLN
 226 };
 227
 228 static const int ftw_arr[] =
 229 {
 230   FTW_F, FTW_D, FTW_DNR, FTW_NS, FTW_F, FTW_D, FTW_NS
 231 };
 232
 233
 234 /* Forward declarations of local functions.  */
 235 static int ftw_dir (struct ftw_data *data, struct STRUCT_STAT *st,
 236                     struct dir_data *old_dir);
 237
 238
 239 static int
 240 object_compare (const void *p1, const void *p2)
 241 {
 242   /* We don't need a sophisticated and useful comparison.  We are only
 243      interested in equality.  However, we must be careful not to
 244      accidentally compare `holes' in the structure.  */
 245   const struct known_object *kp1 = p1, *kp2 = p2;
 246   int cmp1;
 247   cmp1 = (kp1->ino > kp2->ino) - (kp1->ino < kp2->ino);
 248   if (cmp1 != 0)
 249     return cmp1;
 250   return (kp1->dev > kp2->dev) - (kp1->dev < kp2->dev);
 251 }
 252
 253
 254 static int
 255 add_object (struct ftw_data *data, struct STRUCT_STAT *st)
 256 {
 257   struct known_object *newp = malloc (sizeof (struct known_object));
 258   if (newp == NULL)
 259     return -1;
 260   newp->dev = st->st_dev;
 261   newp->ino = st->st_ino;
 262   return __tsearch (newp, &data->known_objects, object_compare) ? 0 : -1;
 263 }
 264
 265
 266 static inline int
 267 find_object (struct ftw_data *data, struct STRUCT_STAT *st)
 268 {
 269   struct known_object obj;
 270   obj.dev = st->st_dev;
 271   obj.ino = st->st_ino;
 272   return __tfind (&obj, &data->known_objects, object_compare) != NULL;
 273 }
 274
 275
 276 static inline int
 277 __attribute ((always_inline))
 278 open_dir_stream (int *dfdp, struct ftw_data *data, struct dir_data *dirp)
 279 {
 280   int result = 0;
 281
 282   if (data->dirstreams[data->actdir] != NULL)
 283     {
 284       /* Oh, oh.  We must close this stream.  Get all remaining
 285          entries and store them as a list in the `content' member of
 286          the `struct dir_data' variable.  */
 287       size_t bufsize = 1024;
 288       char *buf = malloc (bufsize);
 289
 290       if (buf == NULL)
 291         result = -1;
 292       else
 293         {
 294           DIR *st = data->dirstreams[data->actdir]->stream;
 295           struct dirent64 *d;
 296           size_t actsize = 0;
 297
 298           while ((d = __readdir64 (st)) != NULL)
 299             {
 300               size_t this_len = NAMLEN (d);
 301               if (actsize + this_len + 2 >= bufsize)
 302                 {
 303                   char *newp;
 304                   bufsize += MAX (1024, 2 * this_len);
 305                   newp = (char *) realloc (buf, bufsize);
 306                   if (newp == NULL)
 307                     {
 308                       /* No more memory.  */
 309                       int save_err = errno;
 310                       free (buf);
 311                       __set_errno (save_err);
 312                       return -1;
 313                     }
 314                   buf = newp;
 315                 }
 316
 317               *((char *) __mempcpy (buf + actsize, d->d_name, this_len))
 318                 = '\0';
 319               actsize += this_len + 1;
 320             }
 321
 322           /* Terminate the list with an additional NUL byte.  */
 323           buf[actsize++] = '\0';
 324
 325           /* Shrink the buffer to what we actually need.  */
 326           void *content = realloc (buf, actsize);
 327           data->dirstreams[data->actdir]->content = content;
 328           if (content == NULL)
 329             {
 330               int save_err = errno;
 331               free (buf);
 332               __set_errno (save_err);
 333               result = -1;
 334             }
 335           else
 336             {
 337               __closedir (st);
 338               data->dirstreams[data->actdir]->stream = NULL;
 339               data->dirstreams[data->actdir]->streamfd = -1;
 340               data->dirstreams[data->actdir] = NULL;
 341             }
 342         }
 343     }
 344
 345   /* Open the new stream.  */
 346   if (result == 0)
 347     {
 348       assert (data->dirstreams[data->actdir] == NULL);
 349
 350       if (dfdp != NULL && *dfdp != -1)
 351         {
 352           int fd = __openat64_nocancel (*dfdp, data->dirbuf + data->ftw.base,
 353                                         O_RDONLY | O_DIRECTORY | O_NDELAY);
 354           dirp->stream = NULL;
 355           if (fd != -1 && (dirp->stream = __fdopendir (fd)) == NULL)
 356             __close_nocancel_nostatus (fd);
 357         }
 358       else
 359         {
 360           const char *name;
 361
 362           if (data->flags & FTW_CHDIR)
 363             {
 364               name = data->dirbuf + data->ftw.base;
 365               if (name[0] == '\0')
 366                 name = ".";
 367             }
 368           else
 369             name = data->dirbuf;
 370
 371           dirp->stream = __opendir (name);
 372         }
 373
 374       if (dirp->stream == NULL)
 375         result = -1;
 376       else
 377         {
 378           dirp->streamfd = __dirfd (dirp->stream);
 379           dirp->content = NULL;
 380           data->dirstreams[data->actdir] = dirp;
 381
 382           if (++data->actdir == data->maxdir)
 383             data->actdir = 0;
 384         }
 385     }
 386
 387   return result;
 388 }
 389
 390
 391 static int
 392 process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
 393                size_t namlen, int d_type)
 394 {
 395   struct STRUCT_STAT st;
 396   int result = 0;
 397   int flag = 0;
 398   size_t new_buflen;
 399
 400   if (name[0] == '.' && (name[1] == '\0'
 401                          || (name[1] == '.' && name[2] == '\0')))
 402     /* Don't process the "." and ".." entries.  */
 403     return 0;
 404
 405   new_buflen = data->ftw.base + namlen + 2;
 406   if (data->dirbufsize < new_buflen
 407       && !ftw_allocate (data, 2 * new_buflen))
 408     return -1;
 409
 410   *((char *) __mempcpy (data->dirbuf + data->ftw.base, name, namlen)) = '\0';
 411
 412   int statres;
 413   if (dir->streamfd != -1)
 414     statres = FSTATAT (dir->streamfd, name, &st,
 415                        (data->flags & FTW_PHYS) ? AT_SYMLINK_NOFOLLOW : 0);
 416   else
 417     {
 418       if ((data->flags & FTW_CHDIR) == 0)
 419         name = data->dirbuf;
 420
 421       statres = ((data->flags & FTW_PHYS)
 422                  ? LSTAT (name, &st)
 423                  : STAT (name, &st));
 424     }
 425
 426   if (statres < 0)
 427     {
 428       if (errno != EACCES && errno != ENOENT)
 429         result = -1;
 430       else if (data->flags & FTW_PHYS)
 431         flag = FTW_NS;
 432       else
 433         {
 434           /* Old code left ST undefined for dangling DT_LNK without
 435              FTW_PHYS set; a clarification at the POSIX level suggests
 436              it should contain information about the link (ala lstat).
 437              We do our best to fill in what data we can.  */
 438           if (dir->streamfd != -1)
 439             statres = FSTATAT (dir->streamfd, name, &st,
 440                                AT_SYMLINK_NOFOLLOW);
 441           else
 442             statres = LSTAT (name, &st);
 443           if (statres == 0 && S_ISLNK (st.st_mode))
 444             flag = FTW_SLN;
 445           else
 446             flag = FTW_NS;
 447         }
 448     }
 449   else
 450     {
 451       if (S_ISDIR (st.st_mode))
 452         flag = FTW_D;
 453       else if (S_ISLNK (st.st_mode))
 454         flag = FTW_SL;
 455       else
 456         flag = FTW_F;
 457     }
 458
 459   if (result == 0
 460       && (flag == FTW_NS
 461           || !(data->flags & FTW_MOUNT) || st.st_dev == data->dev))
 462     {
 463       if (flag == FTW_D)
 464         {
 465           if ((data->flags & FTW_PHYS)
 466               || (!find_object (data, &st)
 467                   /* Remember the object.  */
 468                   && (result = add_object (data, &st)) == 0))
 469             result = ftw_dir (data, &st, dir);
 470         }
 471       else
 472         result = (*data->func) (data->dirbuf, &st, data->cvt_arr[flag],
 473                                 &data->ftw);
 474     }
 475
 476   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SUBTREE)
 477     result = 0;
 478
 479   return result;
 480 }
 481
 482
 483 static int
 484 __attribute ((noinline))
 485 ftw_dir (struct ftw_data *data, struct STRUCT_STAT *st, struct dir_data *old_dir)
 486 {
 487   struct dir_data dir;
 488   struct dirent64 *d;
 489   int previous_base = data->ftw.base;
 490   int result;
 491   char *startp;
 492
 493   /* Open the stream for this directory.  This might require that
 494      another stream has to be closed.  */
 495   result = open_dir_stream (old_dir == NULL ? NULL : &old_dir->streamfd,
 496                             data, &dir);
 497   if (result != 0)
 498     {
 499       if (errno == EACCES)
 500         /* We cannot read the directory.  Signal this with a special flag.  */
 501         result = (*data->func) (data->dirbuf, st, FTW_DNR, &data->ftw);
 502
 503       return result;
 504     }
 505
 506   /* First, report the directory (if not depth-first).  */
 507   if (!(data->flags & FTW_DEPTH))
 508     {
 509       result = (*data->func) (data->dirbuf, st, FTW_D, &data->ftw);
 510       if (result != 0)
 511         {
 512           int save_err;
 513 fail:
 514           save_err = errno;
 515           __closedir (dir.stream);
 516           dir.streamfd = -1;
 517           __set_errno (save_err);
 518
 519           if (data->actdir-- == 0)
 520             data->actdir = data->maxdir - 1;
 521           data->dirstreams[data->actdir] = NULL;
 522           return result;
 523         }
 524     }
 525
 526   /* If necessary, change to this directory.  */
 527   if (data->flags & FTW_CHDIR)
 528     {
 529       if (__fchdir (__dirfd (dir.stream)) < 0)
 530         {
 531           result = -1;
 532           goto fail;
 533         }
 534     }
 535
 536   /* Next, update the `struct FTW' information.  */
 537   ++data->ftw.level;
 538   startp = __rawmemchr (data->dirbuf, '\0');
 539   /* There always must be a directory name.  */
 540   assert (startp != data->dirbuf);
 541   if (startp[-1] != '/')
 542     *startp++ = '/';
 543   data->ftw.base = startp - data->dirbuf;
 544
 545   while (dir.stream != NULL && (d = __readdir64 (dir.stream)) != NULL)
 546     {
 547       int d_type = DT_UNKNOWN;
 548 #ifdef _DIRENT_HAVE_D_TYPE
 549       d_type = d->d_type;
 550 #endif
 551       result = process_entry (data, &dir, d->d_name, NAMLEN (d), d_type);
 552       if (result != 0)
 553         break;
 554     }
 555
 556   if (dir.stream != NULL)
 557     {
 558       /* The stream is still open.  I.e., we did not need more
 559          descriptors.  Simply close the stream now.  */
 560       int save_err = errno;
 561
 562       assert (dir.content == NULL);
 563
 564       __closedir (dir.stream);
 565       dir.streamfd = -1;
 566       __set_errno (save_err);
 567
 568       if (data->actdir-- == 0)
 569         data->actdir = data->maxdir - 1;
 570       data->dirstreams[data->actdir] = NULL;
 571     }
 572   else
 573     {
 574       int save_err;
 575       char *runp = dir.content;
 576
 577       while (result == 0 && *runp != '\0')
 578         {
 579           char *endp = strchr (runp, '\0');
 580
 581           // XXX Should store the d_type values as well?!
 582           result = process_entry (data, &dir, runp, endp - runp, DT_UNKNOWN);
 583
 584           runp = endp + 1;
 585         }
 586
 587       save_err = errno;
 588       free (dir.content);
 589       __set_errno (save_err);
 590     }
 591
 592   if ((data->flags & FTW_ACTIONRETVAL) && result == FTW_SKIP_SIBLINGS)
 593     result = 0;
 594
 595   /* Prepare the return, revert the `struct FTW' information.  */
 596   data->dirbuf[data->ftw.base - 1] = '\0';
 597   --data->ftw.level;
 598   data->ftw.base = previous_base;
 599
 600   /* Finally, if we process depth-first report the directory.  */
 601   if (result == 0 && (data->flags & FTW_DEPTH))
 602     result = (*data->func) (data->dirbuf, st, FTW_DP, &data->ftw);
 603
 604   if (old_dir
 605       && (data->flags & FTW_CHDIR)
 606       && (result == 0
 607           || ((data->flags & FTW_ACTIONRETVAL)
 608               && (result != -1 && result != FTW_STOP))))
 609     {
 610       /* Change back to the parent directory.  */
 611       int done = 0;
 612       if (old_dir->stream != NULL)
 613         if (__fchdir (__dirfd (old_dir->stream)) == 0)
 614           done = 1;
 615
 616       if (!done)
 617         {
 618           if (data->ftw.base == 1)
 619             {
 620               if (__chdir ("/") < 0)
 621                 result = -1;
 622             }
 623           else
 624             if (__chdir ("..") < 0)
 625               result = -1;
 626         }
 627     }
 628
 629   return result;
 630 }
 631
 632
 633 static int
 634 __attribute ((noinline))
 635 ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 636              int flags)
 637 {
 638   struct ftw_data data = { .dirstreams = NULL };
 639   struct STRUCT_STAT st;
 640   int result = 0;
 641   int save_err;
 642   int cwdfd = -1;
 643   char *cwd = NULL;
 644   char *cp;
 645
 646   /* First make sure the parameters are reasonable.  */
 647   if (dir[0] == '\0')
 648     {
 649       __set_errno (ENOENT);
 650       return -1;
 651     }
 652
 653   data.maxdir = descriptors < 1 ? 1 : descriptors;
 654   data.actdir = 0;
 655   /* PATH_MAX is always defined when we get here.  */
 656   if (!ftw_allocate (&data, MAX (2 * strlen (dir), PATH_MAX)))
 657     return -1;
 658   memset (data.dirstreams, '\0', data.maxdir * sizeof (struct dir_data *));
 659   cp = __stpcpy (data.dirbuf, dir);
 660   /* Strip trailing slashes.  */
 661   while (cp > data.dirbuf + 1 && cp[-1] == '/')
 662     --cp;
 663   *cp = '\0';
 664
 665   data.ftw.level = 0;
 666
 667   /* Find basename.  */
 668   while (cp > data.dirbuf && cp[-1] != '/')
 669     --cp;
 670   data.ftw.base = cp - data.dirbuf;
 671
 672   data.flags = flags;
 673
 674   /* This assignment might seem to be strange but it is what we want.
 675      The trick is that the first three arguments to the `ftw' and
 676      `nftw' callback functions are equal.  Therefore we can call in
 677      every case the callback using the format of the `nftw' version
 678      and get the correct result since the stack layout for a function
 679      call in C allows this.  */
 680   data.func = (NFTW_FUNC_T) func;
 681
 682   /* Since we internally use the complete set of FTW_* values we need
 683      to reduce the value range before calling a `ftw' callback.  */
 684   data.cvt_arr = is_nftw ? nftw_arr : ftw_arr;
 685
 686   /* No object known so far.  */
 687   data.known_objects = NULL;
 688
 689   /* Now go to the directory containing the initial file/directory.  */
 690   if (flags & FTW_CHDIR)
 691     {
 692       /* We have to be able to go back to the current working
 693          directory.  The best way to do this is to use a file
 694          descriptor.  */
 695       cwdfd = __open (".", O_RDONLY | O_DIRECTORY);
 696       if (cwdfd == -1)
 697         {
 698           /* Try getting the directory name.  This can be needed if
 699              the current directory is executable but not readable.  */
 700           if (errno == EACCES)
 701             /* GNU extension ahead.  */
 702             cwd =  __getcwd (NULL, 0);
 703
 704           if (cwd == NULL)
 705             goto out_fail;
 706         }
 707       else if (data.maxdir > 1)
 708         /* Account for the file descriptor we use here.  */
 709         --data.maxdir;
 710
 711       if (data.ftw.base > 0)
 712         {
 713           /* Change to the directory the file is in.  In data.dirbuf
 714              we have a writable copy of the file name.  Just NUL
 715              terminate it for now and change the directory.  */
 716           if (data.ftw.base == 1)
 717             /* I.e., the file is in the root directory.  */
 718             result = __chdir ("/");
 719           else
 720             {
 721               char ch = data.dirbuf[data.ftw.base - 1];
 722               data.dirbuf[data.ftw.base - 1] = '\0';
 723               result = __chdir (data.dirbuf);
 724               data.dirbuf[data.ftw.base - 1] = ch;
 725             }
 726         }
 727     }
 728
 729   /* Get stat info for start directory.  */
 730   if (result == 0)
 731     {
 732       const char *name;
 733
 734       if (data.flags & FTW_CHDIR)
 735         {
 736           name = data.dirbuf + data.ftw.base;
 737           if (name[0] == '\0')
 738             name = ".";
 739         }
 740       else
 741         name = data.dirbuf;
 742
 743       if (((flags & FTW_PHYS)
 744            ? LSTAT (name, &st)
 745            : STAT (name, &st)) < 0)
 746         {
 747           if (!(flags & FTW_PHYS)
 748               && errno == ENOENT
 749               && LSTAT (name, &st) == 0
 750               && S_ISLNK (st.st_mode))
 751             result = (*data.func) (data.dirbuf, &st, data.cvt_arr[FTW_SLN],
 752                                    &data.ftw);
 753           else
 754             /* No need to call the callback since we cannot say anything
 755                about the object.  */
 756             result = -1;
 757         }
 758       else
 759         {
 760           if (S_ISDIR (st.st_mode))
 761             {
 762               /* Remember the device of the initial directory in case
 763                  FTW_MOUNT is given.  */
 764               data.dev = st.st_dev;
 765
 766               /* We know this directory now.  */
 767               if (!(flags & FTW_PHYS))
 768                 result = add_object (&data, &st);
 769
 770               if (result == 0)
 771                 result = ftw_dir (&data, &st, NULL);
 772             }
 773           else
 774             {
 775               int flag = S_ISLNK (st.st_mode) ? FTW_SL : FTW_F;
 776
 777               result = (*data.func) (data.dirbuf, &st, data.cvt_arr[flag],
 778                                      &data.ftw);
 779             }
 780         }
 781
 782       if ((flags & FTW_ACTIONRETVAL)
 783           && (result == FTW_SKIP_SUBTREE || result == FTW_SKIP_SIBLINGS))
 784         result = 0;
 785     }
 786
 787   /* Return to the start directory (if necessary).  */
 788   if (cwdfd != -1)
 789     {
 790       int save_err = errno;
 791       __fchdir (cwdfd);
 792       __close_nocancel_nostatus (cwdfd);
 793       __set_errno (save_err);
 794     }
 795   else if (cwd != NULL)
 796     {
 797       int save_err = errno;
 798       __chdir (cwd);
 799       free (cwd);
 800       __set_errno (save_err);
 801     }
 802
 803   /* Free all memory.  */
 804  out_fail:
 805   save_err = errno;
 806   __tdestroy (data.known_objects, free);
 807   free (data.dirstreams);
 808   __set_errno (save_err);
 809
 810   return result;
 811 }
 812
 813
 814
 815 /* Entry points.  */
 816
 817 int
 818 FTW_NAME (const char *path, FTW_FUNC_T func, int descriptors)
 819 {
 820   return ftw_startup (path, 0, func, descriptors, 0);
 821 }
 822
 823 #ifndef NFTW_OLD_NAME
 824 int
 825 NFTW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 826 {
 827   return ftw_startup (path, 1, func, descriptors, flags);
 828 }
 829 #else
 830
 831 # include <shlib-compat.h>
 832
 833 int NFTW_NEW_NAME (const char *, NFTW_FUNC_T, int, int);
 834
 835 int
 836 NFTW_NEW_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 837 {
 838   if (flags
 839       & ~(FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH | FTW_ACTIONRETVAL))
 840     {
 841       __set_errno (EINVAL);
 842       return -1;
 843     }
 844   return ftw_startup (path, 1, func, descriptors, flags);
 845 }
 846 versioned_symbol (libc, NFTW_NEW_NAME, NFTW_NAME, GLIBC_2_3_3);
 847
 848 # if SHLIB_COMPAT(libc, GLIBC_2_1, GLIBC_2_3_3)
 849
 850 /* Older nftw* version just ignored all unknown flags.  */
 851
 852 int NFTW_OLD_NAME (const char *, NFTW_FUNC_T, int, int);
 853
 854 int
 855 attribute_compat_text_section
 856 NFTW_OLD_NAME (const char *path, NFTW_FUNC_T func, int descriptors, int flags)
 857 {
 858   flags &= (FTW_PHYS | FTW_MOUNT | FTW_CHDIR | FTW_DEPTH);
 859   return ftw_startup (path, 1, func, descriptors, flags);
 860 }
 861
 862 compat_symbol (libc, NFTW_OLD_NAME, NFTW_NAME, GLIBC_2_1);
 863 # endif
 864 #endif /* NFTW_OLD_NAME  */