dirent/scandir-tail.c

   1 /* Logic guts of scandir*.
   2    Copyright (C) 1992-2017 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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <dirent.h>
  20 #include <errno.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <libc-lock.h>
  24
  25 #ifndef SCANDIR_TAIL
  26 # define SCANDIR_TAIL   __scandir_tail
  27 # define READDIR        __readdir
  28 # define DIRENT_TYPE    struct dirent
  29 #endif
  30
  31 internal_function
  32 int
  33 SCANDIR_TAIL (DIR *dp,
  34               DIRENT_TYPE ***namelist,
  35               int (*select) (const DIRENT_TYPE *),
  36               int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **))
  37 {
  38   if (dp == NULL)
  39     return -1;
  40
  41   int save = errno;
  42   __set_errno (0);
  43
  44   int result;
  45   struct scandir_cancel_struct c = { .dp = dp };
  46   __libc_cleanup_push (&__scandir_cancel_handler, &c);
  47
  48   DIRENT_TYPE **v = NULL;
  49   size_t vsize = 0;
  50   DIRENT_TYPE *d;
  51   while ((d = READDIR (dp)) != NULL)
  52     {
  53       if (select != NULL)
  54         {
  55           int selected = (*select) (d);
  56
  57           /* The SELECT function might have changed errno.  It was
  58              zero before and it need to be again to make the later
  59              tests work.  */
  60           __set_errno (0);
  61
  62           if (!selected)
  63             continue;
  64         }
  65       else
  66         __set_errno (0);
  67
  68       if (__glibc_unlikely (c.cnt == vsize))
  69         {
  70           if (vsize == 0)
  71             vsize = 10;
  72           else
  73             vsize *= 2;
  74           DIRENT_TYPE **new = realloc (v, vsize * sizeof *v);
  75           if (new == NULL)
  76             break;
  77           c.v = v = new;
  78         }
  79
  80       size_t dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
  81       DIRENT_TYPE *vnew = malloc (dsize);
  82       if (vnew == NULL)
  83         break;
  84       v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
  85     }
  86
  87   if (__glibc_likely (errno == 0))
  88     {
  89       __closedir (dp);
  90
  91       /* Sort the list if we have a comparison function to sort with.  */
  92       if (cmp != NULL)
  93         qsort (v, c.cnt, sizeof *v, (__compar_fn_t) cmp);
  94
  95       *namelist = v;
  96       result = c.cnt;
  97     }
  98   else
  99     {
 100       /* This frees everything and calls closedir.  */
 101       __scandir_cancel_handler (&c);
 102       result = -1;
 103     }
 104
 105   __libc_cleanup_pop (0);
 106
 107   if (result >= 0)
 108     __set_errno (save);
 109   return result;
 110 }