lib/scandir.c

   1 /* Copyright (C) 1992-1998, 2000, 2002-2003, 2009-2025 Free Software
   2    Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation, either version 3 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #include <config.h>
  19
  20 #include <dirent.h>
  21
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #if _LIBC
  26 # include <bits/libc-lock.h>
  27 #endif
  28
  29 #undef select
  30
  31 #ifndef _D_EXACT_NAMLEN
  32 # define _D_EXACT_NAMLEN(d) strlen ((d)->d_name)
  33 #endif
  34 #ifndef _D_ALLOC_NAMLEN
  35 # ifndef __KLIBC__
  36 #  define _D_ALLOC_NAMLEN(d) (_D_EXACT_NAMLEN (d) + 1)
  37 # else
  38 /* On OS/2 kLIBC, d_name is not the last field of struct dirent. See
  39    <https://trac.netlabs.org/libc/browser/branches/libc-0.6/src/emx/include/sys/dirent.h#L68>.  */
  40 #  include <stddef.h>
  41 #  define _D_ALLOC_NAMLEN(d) (sizeof (struct dirent) - \
  42                               offsetof (struct dirent, d_name))
  43 # endif
  44 #endif
  45
  46 #if _LIBC
  47 # ifndef SCANDIR
  48 #  define SCANDIR scandir
  49 #  define READDIR __readdir
  50 #  define DIRENT_TYPE struct dirent
  51 # endif
  52 #else
  53 # define SCANDIR scandir
  54 # define READDIR readdir
  55 # define DIRENT_TYPE struct dirent
  56 # define __opendir opendir
  57 # define __closedir closedir
  58 # define __set_errno(val) errno = (val)
  59
  60 /* The results of opendir() in this file are not used with dirfd and fchdir,
  61    and we do not leak fds to any single-threaded code that could use stdio,
  62    therefore save some unnecessary recursion in fchdir.c and opendir_safer.c.
  63    FIXME - if the kernel ever adds support for multi-thread safety for
  64    avoiding standard fds, then we should use opendir_safer.  */
  65 # ifdef GNULIB_defined_DIR
  66 #  undef DIR
  67 #  undef opendir
  68 #  undef closedir
  69 #  undef readdir
  70 # else
  71 #  ifdef GNULIB_defined_opendir
  72 #   undef opendir
  73 #  endif
  74 #  ifdef GNULIB_defined_closedir
  75 #   undef closedir
  76 #  endif
  77 # endif
  78 #endif
  79
  80 #ifndef SCANDIR_CANCEL
  81 # define SCANDIR_CANCEL
  82 struct scandir_cancel_struct
  83 {
  84   DIR *dp;
  85   void *v;
  86   size_t cnt;
  87 };
  88
  89 # if _LIBC
  90 static void
  91 cancel_handler (void *arg)
  92 {
  93   struct scandir_cancel_struct *cp = arg;
  94   size_t i;
  95   void **v = cp->v;
  96
  97   for (i = 0; i < cp->cnt; ++i)
  98     free (v[i]);
  99   free (v);
 100   (void) __closedir (cp->dp);
 101 }
 102 # endif
 103 #endif
 104
 105
 106 int
 107 #ifndef __KLIBC__
 108 SCANDIR (const char *dir,
 109          DIRENT_TYPE ***namelist,
 110          int (*select) (const DIRENT_TYPE *),
 111          int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))
 112 #else
 113 /* On OS/2 kLIBC, scandir() declaration is different from POSIX. See
 114    <https://trac.netlabs.org/libc/browser/branches/libc-0.6/src/emx/include/dirent.h#L141>.  */
 115 SCANDIR (const char *dir,
 116          DIRENT_TYPE ***namelist,
 117          int (*select) (DIRENT_TYPE *),
 118          int (*cmp) (const void *, const void *))
 119 #endif
 120 {
 121   DIR *dp = __opendir (dir);
 122   DIRENT_TYPE **v = NULL;
 123   size_t vsize = 0;
 124   struct scandir_cancel_struct c;
 125   DIRENT_TYPE *d;
 126   int save;
 127
 128   if (dp == NULL)
 129     return -1;
 130
 131   save = errno;
 132   __set_errno (0);
 133
 134   c.dp = dp;
 135   c.v = NULL;
 136   c.cnt = 0;
 137 #if _LIBC
 138   __libc_cleanup_push (cancel_handler, &c);
 139 #endif
 140
 141   while ((d = READDIR (dp)) != NULL)
 142     {
 143       int use_it = select == NULL;
 144
 145       if (! use_it)
 146         {
 147           use_it = select (d);
 148           /* The select function might have changed errno.  It was
 149              zero before and it need to be again to make the latter
 150              tests work.  */
 151           __set_errno (0);
 152         }
 153
 154       if (use_it)
 155         {
 156           DIRENT_TYPE *vnew;
 157           size_t dsize;
 158
 159           /* Ignore errors from select or readdir */
 160           __set_errno (0);
 161
 162           if (__builtin_expect (c.cnt == vsize, 0))
 163             {
 164               DIRENT_TYPE **new;
 165               if (vsize == 0)
 166                 vsize = 10;
 167               else
 168                 vsize *= 2;
 169               new = (DIRENT_TYPE **) realloc (v, vsize * sizeof (*v));
 170               if (new == NULL)
 171                 break;
 172               v = new;
 173               c.v = (void *) v;
 174             }
 175
 176           dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
 177           vnew = (DIRENT_TYPE *) malloc (dsize);
 178           if (vnew == NULL)
 179             break;
 180
 181           v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
 182         }
 183     }
 184
 185   if (__builtin_expect (errno, 0) != 0)
 186     {
 187       save = errno;
 188
 189       while (c.cnt > 0)
 190         free (v[--c.cnt]);
 191       free (v);
 192       c.cnt = -1;
 193     }
 194   else
 195     {
 196       /* Sort the list if we have a comparison function to sort with.  */
 197       if (cmp != NULL)
 198         qsort (v, c.cnt, sizeof (*v), (int (*) (const void *, const void *)) cmp);
 199
 200       *namelist = v;
 201     }
 202
 203 #if _LIBC
 204   __libc_cleanup_pop (0);
 205 #endif
 206
 207   (void) __closedir (dp);
 208   __set_errno (save);
 209
 210   return c.cnt;
 211 }