lib/savedir.c

   1 /* savedir.c -- save the list of files in a directory in a string
   2    Copyright (C) 1990 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
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  17
  18 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>. */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <sys/types.h>
  25
  26 #ifdef 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 #endif
  58 #ifndef NULL
  59 #define NULL 0
  60 #endif
  61
  62 char *stpcpy ();
  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    NAME_SIZE is the number of bytes to initially allocate
  68    for the string; it will be enlarged as needed.
  69    Return NULL if DIR cannot be opened or if out of memory. */
  70
  71 char *
  72 savedir (dir, name_size)
  73      char *dir;
  74      unsigned name_size;
  75 {
  76   DIR *dirp;
  77   struct dirent *dp;
  78   char *name_space;
  79   char *namep;
  80
  81   dirp = opendir (dir);
  82   if (dirp == NULL)
  83     return NULL;
  84
  85   name_space = (char *) malloc (name_size);
  86   if (name_space == NULL)
  87     {
  88       closedir (dirp);
  89       return NULL;
  90     }
  91   namep = name_space;
  92
  93   while ((dp = readdir (dirp)) != NULL)
  94     {
  95       /* Skip "." and ".." (some NFS filesystems' directories lack them). */
  96       if (dp->d_name[0] != '.'
  97           || (dp->d_name[1] != '\0'
  98               && (dp->d_name[1] != '.' || dp->d_name[2] != '\0')))
  99         {
 100           unsigned size_needed = (namep - name_space) + NAMLEN (dp) + 2;
 101
 102           if (size_needed > name_size)
 103             {
 104               char *new_name_space;
 105
 106               while (size_needed > name_size)
 107                 name_size += 1024;
 108
 109               new_name_space = realloc (name_space, name_size);
 110               if (new_name_space == NULL)
 111                 {
 112                   closedir (dirp);
 113                   return NULL;
 114                 }
 115               namep += new_name_space - name_space;
 116               name_space = new_name_space;
 117             }
 118           namep = stpcpy (namep, dp->d_name) + 1;
 119         }
 120     }
 121   *namep = '\0';
 122   if (CLOSEDIR (dirp))
 123     {
 124       free (name_space);
 125       return NULL;
 126     }
 127   return name_space;
 128 }