lib/savedir.c

   1 /* savedir.c -- save the list of files in a directory in a string
   2
   3    Copyright 1990, 1997, 1998, 1999, 2000, 2001, 2003 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software Foundation,
  18    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  19
  20 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
  21
  22 #if HAVE_CONFIG_H
  23 # include <config.h>
  24 #endif
  25
  26 #include "savedir.h"
  27
  28 #include <sys/types.h>
  29
  30 #include <errno.h>
  31 #ifndef errno
  32 extern int errno;
  33 #endif
  34
  35 #if HAVE_DIRENT_H
  36 # include <dirent.h>
  37 #else
  38 # define dirent direct
  39 # if HAVE_SYS_NDIR_H
  40 #  include <sys/ndir.h>
  41 # endif
  42 # if HAVE_SYS_DIR_H
  43 #  include <sys/dir.h>
  44 # endif
  45 # if HAVE_NDIR_H
  46 #  include <ndir.h>
  47 # endif
  48 #endif
  49
  50 #ifdef CLOSEDIR_VOID
  51 /* Fake a return value. */
  52 # define CLOSEDIR(d) (closedir (d), 0)
  53 #else
  54 # define CLOSEDIR(d) closedir (d)
  55 #endif
  56
  57 #include <stddef.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60
  61 #include "xalloc.h"
  62
  63 /* Return a freshly allocated string containing the filenames
  64    in directory DIR, separated by '\0' characters;
  65    the end is marked by two '\0' characters in a row.
  66    Return NULL (setting errno) if DIR cannot be opened, read, or closed.  */
  67
  68 #ifndef NAME_SIZE_DEFAULT
  69 # define NAME_SIZE_DEFAULT 512
  70 #endif
  71
  72 char *
  73 savedir (const char *dir)
  74 {
  75   DIR *dirp;
  76   struct dirent *dp;
  77   char *name_space;
  78   size_t allocated = NAME_SIZE_DEFAULT;
  79   size_t used = 0;
  80   int save_errno;
  81
  82   dirp = opendir (dir);
  83   if (dirp == NULL)
  84     return NULL;
  85
  86   name_space = xmalloc (allocated);
  87
  88   errno = 0;
  89   while ((dp = readdir (dirp)) != NULL)
  90     {
  91       /* Skip "", ".", and "..".  "" is returned by at least one buggy
  92          implementation: Solaris 2.4 readdir on NFS filesystems.  */
  93       char const *entry = dp->d_name;
  94       if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0')
  95         {
  96           size_t entry_size = strlen (entry) + 1;
  97           if (used + entry_size < used)
  98             xalloc_die ();
  99           if (allocated <= used + entry_size)
 100             {
 101               do
 102                 {
 103                   if (2 * allocated < allocated)
 104                     xalloc_die ();
 105                   allocated *= 2;
 106                 }
 107               while (allocated <= used + entry_size);
 108
 109               name_space = xrealloc (name_space, allocated);
 110             }
 111           memcpy (name_space + used, entry, entry_size);
 112           used += entry_size;
 113         }
 114     }
 115   name_space[used] = '\0';
 116   save_errno = errno;
 117   if (CLOSEDIR (dirp) != 0)
 118     save_errno = errno;
 119   if (save_errno != 0)
 120     {
 121       free (name_space);
 122       errno = save_errno;
 123       return NULL;
 124     }
 125   return name_space;
 126 }