dirent/scandirat.c

   1 /* Copyright (C) 1992-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 /* We need to avoid the header declaration of scandir64, because
  19    the types don't match scandir and then the compiler will
  20    complain about the mismatch when we do the alias below.  */
  21 #define scandirat64       __renamed_scandirat64
  22
  23 #include <dirent.h>
  24
  25 #undef  scandirat64
  26
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <bits/libc-lock.h>
  31
  32 #ifndef SCANDIRAT
  33 # define SCANDIRAT scandirat
  34 # define READDIR __readdir
  35 # define DIRENT_TYPE struct dirent
  36 #endif
  37
  38 #ifndef SKIP_SCANDIR_CANCEL
  39 void
  40 __scandir_cancel_handler (void *arg)
  41 {
  42   struct scandir_cancel_struct *cp = arg;
  43   size_t i;
  44   void **v = cp->v;
  45
  46   for (i = 0; i < cp->cnt; ++i)
  47     free (v[i]);
  48   free (v);
  49   (void) __closedir (cp->dp);
  50 }
  51 #endif
  52
  53
  54 int
  55 SCANDIRAT (dfd, dir, namelist, select, cmp)
  56      int dfd;
  57      const char *dir;
  58      DIRENT_TYPE ***namelist;
  59      int (*select) (const DIRENT_TYPE *);
  60      int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **);
  61 {
  62   DIR *dp = __opendirat (dfd, dir);
  63   DIRENT_TYPE **v = NULL;
  64   size_t vsize = 0;
  65   struct scandir_cancel_struct c;
  66   DIRENT_TYPE *d;
  67   int save;
  68
  69   if (dp == NULL)
  70     return -1;
  71
  72   save = errno;
  73   __set_errno (0);
  74
  75   c.dp = dp;
  76   c.v = NULL;
  77   c.cnt = 0;
  78   __libc_cleanup_push (__scandir_cancel_handler, &c);
  79
  80   while ((d = READDIR (dp)) != NULL)
  81     {
  82       int use_it = select == NULL;
  83
  84       if (! use_it)
  85         {
  86           use_it = select (d);
  87           /* The select function might have changed errno.  It was
  88              zero before and it need to be again to make the latter
  89              tests work.  */
  90           __set_errno (0);
  91         }
  92
  93       if (use_it)
  94         {
  95           DIRENT_TYPE *vnew;
  96           size_t dsize;
  97
  98           /* Ignore errors from select or readdir */
  99           __set_errno (0);
 100
 101           if (__glibc_unlikely (c.cnt == vsize))
 102             {
 103               DIRENT_TYPE **new;
 104               if (vsize == 0)
 105                 vsize = 10;
 106               else
 107                 vsize *= 2;
 108               new = (DIRENT_TYPE **) realloc (v, vsize * sizeof (*v));
 109               if (new == NULL)
 110                 break;
 111               v = new;
 112               c.v = (void *) v;
 113             }
 114
 115           dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
 116           vnew = (DIRENT_TYPE *) malloc (dsize);
 117           if (vnew == NULL)
 118             break;
 119
 120           v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
 121         }
 122     }
 123
 124   if (__builtin_expect (errno, 0) != 0)
 125     {
 126       save = errno;
 127
 128       while (c.cnt > 0)
 129         free (v[--c.cnt]);
 130       free (v);
 131       c.cnt = -1;
 132     }
 133   else
 134     {
 135       /* Sort the list if we have a comparison function to sort with.  */
 136       if (cmp != NULL)
 137         qsort (v, c.cnt, sizeof (*v),
 138                (int (*) (const void *, const void *)) cmp);
 139
 140       *namelist = v;
 141     }
 142
 143   __libc_cleanup_pop (0);
 144
 145   (void) __closedir (dp);
 146   __set_errno (save);
 147
 148   return c.cnt;
 149 }
 150 libc_hidden_def (SCANDIRAT)
 151
 152 #ifdef _DIRENT_MATCHES_DIRENT64
 153 weak_alias (scandirat, scandirat64)
 154 #endif