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@ai.mit.edu>. */
  19
  20 #include <sys/types.h>
  21 #ifdef DIRENT
  22 #include <dirent.h>
  23 #ifdef direct
  24 #undef direct
  25 #endif
  26 #define direct dirent
  27 #define NLENGTH(direct) (strlen((direct)->d_name))
  28 #else
  29 #define NLENGTH(direct) ((direct)->d_namlen)
  30 #ifdef USG
  31 #ifdef SYSNDIR
  32 #include <sys/ndir.h>
  33 #else
  34 #include <ndir.h>
  35 #endif
  36 #else
  37 #include <sys/dir.h>
  38 #endif
  39 #endif
  40
  41 #ifdef VOID_CLOSEDIR
  42 /* Fake a return value. */
  43 #define CLOSEDIR(d) (closedir (d), 0)
  44 #else
  45 #define CLOSEDIR(d) closedir (d)
  46 #endif
  47
  48 #ifdef STDC_HEADERS
  49 #include <stdlib.h>
  50 #include <string.h>
  51 #else
  52 char *malloc ();
  53 char *realloc ();
  54 #ifndef NULL
  55 #define NULL 0
  56 #endif
  57 #endif
  58
  59 char *stpcpy ();
  60
  61 /* Return a freshly allocated string containing the filenames
  62    in directory DIR, separated by '\0' characters;
  63    the end is marked by two '\0' characters in a row.
  64    NAME_SIZE is the number of bytes to initially allocate
  65    for the string; it will be enlarged as needed.
  66    Return NULL if DIR cannot be opened or if out of memory. */
  67
  68 char *
  69 savedir (dir, name_size)
  70      char *dir;
  71      unsigned name_size;
  72 {
  73   DIR *dirp;
  74   struct direct *dp;
  75   char *name_space;
  76   char *namep;
  77
  78   dirp = opendir (dir);
  79   if (dirp == NULL)
  80     return NULL;
  81
  82   name_space = (char *) malloc (name_size);
  83   if (name_space == NULL)
  84     {
  85       closedir (dirp);
  86       return NULL;
  87     }
  88   namep = name_space;
  89
  90   while ((dp = readdir (dirp)) != NULL)
  91     {
  92       /* Skip "." and ".." (some NFS filesystems' directories lack them). */
  93       if (dp->d_name[0] != '.'
  94           || (dp->d_name[1] != '\0'
  95               && (dp->d_name[1] != '.' || dp->d_name[2] != '\0')))
  96         {
  97           unsigned size_needed = (namep - name_space) + NLENGTH (dp) + 2;
  98
  99           if (size_needed > name_size)
 100             {
 101               char *new_name_space;
 102
 103               while (size_needed > name_size)
 104                 name_size += 1024;
 105
 106               new_name_space = realloc (name_space, name_size);
 107               if (new_name_space == NULL)
 108                 {
 109                   closedir (dirp);
 110                   return NULL;
 111                 }
 112               namep += new_name_space - name_space;
 113               name_space = new_name_space;
 114             }
 115           namep = stpcpy (namep, dp->d_name) + 1;
 116         }
 117     }
 118   *namep = '\0';
 119   if (CLOSEDIR (dirp))
 120     {
 121       free (name_space);
 122       return NULL;
 123     }
 124   return name_space;
 125 }