dirent/scandirat.c

   1 /* Copyright (C) 1992-2015 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 # define SCANDIRAT_WEAK_ALIAS
  37 #endif
  38
  39 #ifndef SKIP_SCANDIR_CANCEL
  40 void
  41 __scandir_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 SCANDIRAT (dfd, dir, namelist, select, cmp)
  57      int dfd;
  58      const char *dir;
  59      DIRENT_TYPE ***namelist;
  60      int (*select) (const DIRENT_TYPE *);
  61      int (*cmp) (const DIRENT_TYPE **, const DIRENT_TYPE **);
  62 {
  63   DIR *dp = __opendirat (dfd, dir);
  64   DIRENT_TYPE **v = NULL;
  65   size_t vsize = 0;
  66   struct scandir_cancel_struct c;
  67   DIRENT_TYPE *d;
  68   int save;
  69
  70   if (dp == NULL)
  71     return -1;
  72
  73   save = errno;
  74   __set_errno (0);
  75
  76   c.dp = dp;
  77   c.v = NULL;
  78   c.cnt = 0;
  79   __libc_cleanup_push (__scandir_cancel_handler, &c);
  80
  81   while ((d = READDIR (dp)) != NULL)
  82     {
  83       int use_it = select == NULL;
  84
  85       if (! use_it)
  86         {
  87           use_it = select (d);
  88           /* The select function might have changed errno.  It was
  89              zero before and it need to be again to make the latter
  90              tests work.  */
  91           __set_errno (0);
  92         }
  93
  94       if (use_it)
  95         {
  96           DIRENT_TYPE *vnew;
  97           size_t dsize;
  98
  99           /* Ignore errors from select or readdir */
 100           __set_errno (0);
 101
 102           if (__glibc_unlikely (c.cnt == vsize))
 103             {
 104               DIRENT_TYPE **new;
 105               if (vsize == 0)
 106                 vsize = 10;
 107               else
 108                 vsize *= 2;
 109               new = (DIRENT_TYPE **) realloc (v, vsize * sizeof (*v));
 110               if (new == NULL)
 111                 break;
 112               v = new;
 113               c.v = (void *) v;
 114             }
 115
 116           dsize = &d->d_name[_D_ALLOC_NAMLEN (d)] - (char *) d;
 117           vnew = (DIRENT_TYPE *) malloc (dsize);
 118           if (vnew == NULL)
 119             break;
 120
 121           v[c.cnt++] = (DIRENT_TYPE *) memcpy (vnew, d, dsize);
 122         }
 123     }
 124
 125   if (__builtin_expect (errno, 0) != 0)
 126     {
 127       save = errno;
 128
 129       while (c.cnt > 0)
 130         free (v[--c.cnt]);
 131       free (v);
 132       c.cnt = -1;
 133     }
 134   else
 135     {
 136       /* Sort the list if we have a comparison function to sort with.  */
 137       if (cmp != NULL)
 138         qsort (v, c.cnt, sizeof (*v),
 139                (int (*) (const void *, const void *)) cmp);
 140
 141       *namelist = v;
 142     }
 143
 144   __libc_cleanup_pop (0);
 145
 146   (void) __closedir (dp);
 147   __set_errno (save);
 148
 149   return c.cnt;
 150 }
 151 libc_hidden_def (SCANDIRAT)
 152 #ifdef SCANDIRAT_WEAK_ALIAS
 153 weak_alias (__scandirat, scandirat)
 154 #endif
 155
 156 #ifdef _DIRENT_MATCHES_DIRENT64
 157 weak_alias (scandirat, scandirat64)
 158 #endif