lib/savedir.c

   1 /* savedir.c -- save the list of files in a directory in a string
   2    Copyright (C) 1990, 1997, 1998, 1999, 2000 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 #if HAVE_UNISTD_H
  27 # include <unistd.h>
  28 #endif
  29
  30 #if HAVE_DIRENT_H
  31 # include <dirent.h>
  32 # define NAMLEN(dirent) strlen((dirent)->d_name)
  33 #else
  34 # define dirent direct
  35 # define NAMLEN(dirent) (dirent)->d_namlen
  36 # if HAVE_SYS_NDIR_H
  37 #  include <sys/ndir.h>
  38 # endif
  39 # if HAVE_SYS_DIR_H
  40 #  include <sys/dir.h>
  41 # endif
  42 # if HAVE_NDIR_H
  43 #  include <ndir.h>
  44 # endif
  45 #endif
  46
  47 #ifdef CLOSEDIR_VOID
  48 /* Fake a return value. */
  49 # define CLOSEDIR(d) (closedir (d), 0)
  50 #else
  51 # define CLOSEDIR(d) closedir (d)
  52 #endif
  53
  54 #ifdef STDC_HEADERS
  55 # include <stdlib.h>
  56 # include <string.h>
  57 #else
  58 char *malloc ();
  59 char *realloc ();
  60 #endif
  61 #ifndef NULL
  62 # define NULL 0
  63 #endif
  64
  65 #ifndef stpcpy
  66 char *stpcpy ();
  67 #endif
  68
  69 #include "savedir.h"
  70
  71 /* Return a freshly allocated string containing the filenames
  72    in directory DIR, separated by '\0' characters;
  73    the end is marked by two '\0' characters in a row.
  74    NAME_SIZE is the number of bytes to initially allocate
  75    for the string; it will be enlarged as needed.
  76    Return NULL if DIR cannot be opened or if out of memory. */
  77
  78 char *
  79 savedir (const char *dir, off_t name_size)
  80 {
  81   DIR *dirp;
  82   struct dirent *dp;
  83   char *name_space;
  84   char *namep;
  85
  86   dirp = opendir (dir);
  87   if (dirp == NULL)
  88     return NULL;
  89
  90   /* Be sure name_size is at least `1' so there's room for
  91      the final NUL byte.  */
  92   if (name_size <= 0)
  93     name_size = 1;
  94
  95   name_space = (char *) malloc (name_size);
  96   if (name_space == NULL)
  97     {
  98       closedir (dirp);
  99       return NULL;
 100     }
 101   namep = name_space;
 102
 103   while ((dp = readdir (dirp)) != NULL)
 104     {
 105       /* Skip "." and ".." (some NFS filesystems' directories lack them). */
 106       if (dp->d_name[0] != '.'
 107           || (dp->d_name[1] != '\0'
 108               && (dp->d_name[1] != '.' || dp->d_name[2] != '\0')))
 109         {
 110           off_t size_needed = (namep - name_space) + NAMLEN (dp) + 2;
 111
 112           if (size_needed > name_size)
 113             {
 114               char *new_name_space;
 115
 116               while (size_needed > name_size)
 117                 name_size += 1024;
 118
 119               new_name_space = realloc (name_space, name_size);
 120               if (new_name_space == NULL)
 121                 {
 122                   closedir (dirp);
 123                   return NULL;
 124                 }
 125               namep += new_name_space - name_space;
 126               name_space = new_name_space;
 127             }
 128           namep = stpcpy (namep, dp->d_name) + 1;
 129         }
 130     }
 131   *namep = '\0';
 132   if (CLOSEDIR (dirp))
 133     {
 134       free (name_space);
 135       return NULL;
 136     }
 137   return name_space;
 138 }