dirent/scandir.c

   1 /* Copyright (C) 1992-1998,2000,2002,2003,2009 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, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <dirent.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <errno.h>
  23 #include <bits/libc-lock.h>
  24
  25 #ifndef SCANDIR
  26 #define SCANDIR scandir
  27 #define READDIR __readdir
  28 #define DIRENT_TYPE struct dirent
  29 #endif
  30
  31 #ifndef SCANDIR_CANCEL
  32 #define SCANDIR_CANCEL
  33 struct scandir_cancel_struct
  34 {
  35   DIR *dp;
  36   void *v;
  37   size_t cnt;
  38 };
  39
  40 static void
  41 cancel_handler (void *arg)
  42 {
  43   struct scandir_cancel_struct *cp = arg;
  44   size_t i;
  45   void **v = cp->v;
  46
  47   for (i = 0; i < cp->cnt; ++i)
  48     free (v[i]);
  49   free (v);
  50   (void) __closedir (cp->dp);
  51 }
  52 #endif
  53
  54
  55 int
  56 SCANDIR (dir, namelist, select, cmp)
  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 = __opendir (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 (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 (__builtin_expect (c.cnt == vsize, 0))
 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 }