source3/modules/vfs_dirsort.c

   1 /*
   2  * VFS module to provide a sorted directory list.
   3  *
   4  * Copyright (C) Andy Kelk (andy@mopoke.co.uk), 2009
   5  *
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "includes.h"
  22 #include "smbd/smbd.h"
  23 #include "system/filesys.h"
  24
  25 static int compare_dirent (const SMB_STRUCT_DIRENT *da, const SMB_STRUCT_DIRENT *db)
  26 {
  27         return StrCaseCmp(da->d_name, db->d_name);
  28 }
  29
  30 struct dirsort_privates {
  31         long pos;
  32         SMB_STRUCT_DIRENT *directory_list;
  33         long number_of_entries;
  34         time_t mtime;
  35         SMB_STRUCT_DIR *source_directory;
  36         int fd;
  37 };
  38
  39 static void free_dirsort_privates(void **datap) {
  40         TALLOC_FREE(*datap);
  41 }
  42
  43 static bool open_and_sort_dir (vfs_handle_struct *handle)
  44 {
  45         SMB_STRUCT_DIRENT *dp;
  46         struct stat dir_stat;
  47         long current_pos;
  48         struct dirsort_privates *data = NULL;
  49
  50         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
  51                                 return false);
  52
  53         data->number_of_entries = 0;
  54
  55         if (fstat(data->fd, &dir_stat) == 0) {
  56                 data->mtime = dir_stat.st_mtime;
  57         }
  58
  59         while (SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL)
  60                != NULL) {
  61                 data->number_of_entries++;
  62         }
  63
  64         /* Open the underlying directory and count the number of entries
  65            Skip back to the beginning as we'll read it again */
  66         SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
  67
  68         /* Set up an array and read the directory entries into it */
  69         TALLOC_FREE(data->directory_list); /* destroy previous cache if needed */
  70         data->directory_list = talloc_zero_array(data,
  71                                                  SMB_STRUCT_DIRENT,
  72                                                  data->number_of_entries);
  73         if (!data->directory_list) {
  74                 return false;
  75         }
  76         current_pos = data->pos;
  77         data->pos = 0;
  78         while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory,
  79                                           NULL)) != NULL) {
  80                 data->directory_list[data->pos++] = *dp;
  81         }
  82
  83         /* Sort the directory entries by name */
  84         data->pos = current_pos;
  85         TYPESAFE_QSORT(data->directory_list, data->number_of_entries, compare_dirent);
  86         return true;
  87 }
  88
  89 static SMB_STRUCT_DIR *dirsort_opendir(vfs_handle_struct *handle,
  90                                        const char *fname, const char *mask,
  91                                        uint32 attr)
  92 {
  93         struct dirsort_privates *data = NULL;
  94
  95         /* set up our private data about this directory */
  96         data = talloc_zero(handle->conn, struct dirsort_privates);
  97         if (!data) {
  98                 return NULL;
  99         }
 100
 101         data->directory_list = NULL;
 102         data->pos = 0;
 103
 104         /* Open the underlying directory and count the number of entries */
 105         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, fname, mask,
 106                                                       attr);
 107
 108         data->fd = dirfd(data->source_directory);
 109
 110         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 111                                 struct dirsort_privates, return NULL);
 112
 113         if (!open_and_sort_dir(handle)) {
 114                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 115                 return NULL;
 116         }
 117
 118         return data->source_directory;
 119 }
 120
 121 static SMB_STRUCT_DIR *dirsort_fdopendir(vfs_handle_struct *handle,
 122                                         files_struct *fsp,
 123                                         const char *mask,
 124                                         uint32 attr)
 125 {
 126         struct dirsort_privates *data = NULL;
 127
 128         /* set up our private data about this directory */
 129         data = talloc_zero(handle->conn, struct dirsort_privates);
 130         if (!data) {
 131                 return NULL;
 132         }
 133
 134         data->directory_list = NULL;
 135         data->pos = 0;
 136
 137         /* Open the underlying directory and count the number of entries */
 138         data->source_directory = SMB_VFS_NEXT_FDOPENDIR(handle, fsp, mask,
 139                                                       attr);
 140
 141         if (data->source_directory == NULL) {
 142                 TALLOC_FREE(data);
 143                 return NULL;
 144         }
 145
 146         data->fd = dirfd(data->source_directory);
 147
 148         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 149                                 struct dirsort_privates, return NULL);
 150
 151         if (!open_and_sort_dir(handle)) {
 152                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 153                 /* fd is now closed. */
 154                 fsp->fh->fd = -1;
 155                 return NULL;
 156         }
 157
 158         return data->source_directory;
 159 }
 160
 161 static SMB_STRUCT_DIRENT *dirsort_readdir(vfs_handle_struct *handle,
 162                                           SMB_STRUCT_DIR *dirp,
 163                                           SMB_STRUCT_STAT *sbuf)
 164 {
 165         struct dirsort_privates *data = NULL;
 166         time_t current_mtime;
 167         struct stat dir_stat;
 168
 169         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 170                                 return NULL);
 171
 172         if (fstat(data->fd, &dir_stat) == -1) {
 173                 return NULL;
 174         }
 175
 176         current_mtime = dir_stat.st_mtime;
 177
 178         /* throw away cache and re-read the directory if we've changed */
 179         if (current_mtime > data->mtime) {
 180                 open_and_sort_dir(handle);
 181         }
 182
 183         if (data->pos >= data->number_of_entries) {
 184                 return NULL;
 185         }
 186
 187         return &data->directory_list[data->pos++];
 188 }
 189
 190 static void dirsort_seekdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp,
 191                             long offset)
 192 {
 193         struct dirsort_privates *data = NULL;
 194         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 195
 196         data->pos = offset;
 197 }
 198
 199 static long dirsort_telldir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 200 {
 201         struct dirsort_privates *data = NULL;
 202         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 203                                 return -1);
 204
 205         return data->pos;
 206 }
 207
 208 static void dirsort_rewinddir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 209 {
 210         struct dirsort_privates *data = NULL;
 211         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 212
 213         data->pos = 0;
 214 }
 215
 216 static struct vfs_fn_pointers vfs_dirsort_fns = {
 217         .opendir = dirsort_opendir,
 218         .fdopendir = dirsort_fdopendir,
 219         .readdir = dirsort_readdir,
 220         .seekdir = dirsort_seekdir,
 221         .telldir = dirsort_telldir,
 222         .rewind_dir = dirsort_rewinddir,
 223 };
 224
 225 NTSTATUS vfs_dirsort_init(void)
 226 {
 227         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 228                                 &vfs_dirsort_fns);
 229 }