Dogcows Code - chaz/tar/blob - 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 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 <sys/types.h>
  27
  28 #include <errno.h>
  29 #ifndef errno
  30 extern int errno;
  31 #endif
  32
  33 #if HAVE_DIRENT_H
  34 # include <dirent.h>
  35 #else
  36 # define dirent direct
  37 # if HAVE_SYS_NDIR_H
  38 #  include <sys/ndir.h>
  39 # endif
  40 # if HAVE_SYS_DIR_H
  41 #  include <sys/dir.h>
  42 # endif
  43 # if HAVE_NDIR_H
  44 #  include <ndir.h>
  45 # endif
  46 #endif
  47
  48 #ifdef CLOSEDIR_VOID
  49 /* Fake a return value. */
  50 # define CLOSEDIR(d) (closedir (d), 0)
  51 #else
  52 # define CLOSEDIR(d) closedir (d)
  53 #endif
  54
  55 #ifdef STDC_HEADERS
  56 # include <stdlib.h>
  57 # include <string.h>
  58 #endif
  59 #ifndef NULL
  60 # define NULL 0
  61 #endif
  62
  63 #include "savedir.h"
  64 #include "xalloc.h"
  65
  66 /* Return a freshly allocated string containing the filenames
  67    in directory DIR, separated by '\0' characters;
  68    the end is marked by two '\0' characters in a row.
  69    Return NULL (setting errno) if DIR cannot be opened, read, or closed.  */
  70
  71 #ifndef NAME_SIZE_DEFAULT
  72 # define NAME_SIZE_DEFAULT 512
  73 #endif
  74
  75 char *
  76 savedir (const char *dir)
  77 {
  78   DIR *dirp;
  79   struct dirent *dp;
  80   char *name_space;
  81   size_t allocated = NAME_SIZE_DEFAULT;
  82   size_t used = 0;
  83   int save_errno;
  84
  85   dirp = opendir (dir);
  86   if (dirp == NULL)
  87     return NULL;
  88
  89   name_space = xmalloc (allocated);
  90
  91   errno = 0;
  92   while ((dp = readdir (dirp)) != NULL)
  93     {
  94       /* Skip "", ".", and "..".  "" is returned by at least one buggy
  95          implementation: Solaris 2.4 readdir on NFS filesystems.  */
  96       char const *entry = dp->d_name;
  97       if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0')
  98         {
  99           size_t entry_size = strlen (entry) + 1;
 100           if (used + entry_size < used)
 101             xalloc_die ();
 102           if (allocated <= used + entry_size)
 103             {
 104               do
 105                 {
 106                   if (2 * allocated < allocated)
 107                     xalloc_die ();
 108                   allocated *= 2;
 109                 }
 110               while (allocated <= used + entry_size);
 111
 112               name_space = xrealloc (name_space, allocated);
 113             }
 114           memcpy (name_space + used, entry, entry_size);
 115           used += entry_size;
 116         }
 117     }
 118   name_space[used] = '\0';
 119   save_errno = errno;
 120   if (CLOSEDIR (dirp) != 0)
 121     save_errno = errno;
 122   if (save_errno != 0)
 123     {
 124       free (name_space);
 125       errno = save_errno;
 126       return NULL;
 127     }
 128   return name_space;
 129 }