Dogcows Code - chaz/tar/blob - lib/savedir.c

   1 /* savedir.c -- save the list of files in a directory in a string
   2    Copyright 1990,97,98,99,2000, 2001 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software Foundation,
  16    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
  19
  20 #if HAVE_CONFIG_H
  21 # include <config.h>
  22 #endif
  23
  24 #include <sys/types.h>
  25
  26 #include <errno.h>
  27 #ifndef errno
  28 extern int errno;
  29 #endif
  30
  31 #if HAVE_DIRENT_H
  32 # include <dirent.h>
  33 #else
  34 # define dirent direct
  35 # if HAVE_SYS_NDIR_H
  36 #  include <sys/ndir.h>
  37 # endif
  38 # if HAVE_SYS_DIR_H
  39 #  include <sys/dir.h>
  40 # endif
  41 # if HAVE_NDIR_H
  42 #  include <ndir.h>
  43 # endif
  44 #endif
  45
  46 #ifdef CLOSEDIR_VOID
  47 /* Fake a return value. */
  48 # define CLOSEDIR(d) (closedir (d), 0)
  49 #else
  50 # define CLOSEDIR(d) closedir (d)
  51 #endif
  52
  53 #ifdef STDC_HEADERS
  54 # include <stdlib.h>
  55 # include <string.h>
  56 #endif
  57 #ifndef NULL
  58 # define NULL 0
  59 #endif
  60
  61 #include "savedir.h"
  62 #include "xalloc.h"
  63
  64 /* Return a freshly allocated string containing the filenames
  65    in directory DIR, separated by '\0' characters;
  66    the end is marked by two '\0' characters in a row.
  67    Return NULL (setting errno) if DIR cannot be opened, read, or closed.  */
  68
  69 #ifndef NAME_SIZE_DEFAULT
  70 # define NAME_SIZE_DEFAULT 512
  71 #endif
  72
  73 char *
  74 savedir (const char *dir)
  75 {
  76   DIR *dirp;
  77   struct dirent *dp;
  78   char *name_space;
  79   size_t allocated = NAME_SIZE_DEFAULT;
  80   size_t used = 0;
  81   int save_errno;
  82
  83   dirp = opendir (dir);
  84   if (dirp == NULL)
  85     return NULL;
  86
  87   name_space = xmalloc (allocated);
  88
  89   errno = 0;
  90   while ((dp = readdir (dirp)) != NULL)
  91     {
  92       /* Skip "", ".", and "..".  "" is returned by at least one buggy
  93          implementation: Solaris 2.4 readdir on NFS filesystems.  */
  94       char const *entry = dp->d_name;
  95       if (entry[entry[0] != '.' ? 0 : entry[1] != '.' ? 1 : 2] != '\0')
  96         {
  97           size_t entry_size = strlen (entry) + 1;
  98           if (used + entry_size < used)
  99             xalloc_die ();
 100           if (allocated <= used + entry_size)
 101             {
 102               do
 103                 {
 104                   if (2 * allocated < allocated)
 105                     xalloc_die ();
 106                   allocated *= 2;
 107                 }
 108               while (allocated <= used + entry_size);
 109
 110               name_space = xrealloc (name_space, allocated);
 111             }
 112           memcpy (name_space + used, entry, entry_size);
 113           used += entry_size;
 114         }
 115     }
 116   name_space[used] = '\0';
 117   save_errno = errno;
 118   if (CLOSEDIR (dirp) != 0)
 119     save_errno = errno;
 120   if (save_errno != 0)
 121     {
 122       free (name_space);
 123       errno = save_errno;
 124       return NULL;
 125     }
 126   return name_space;
 127 }