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 struct dirent *da, const struct dirent *db)
  26 {
  27         return strcasecmp_m(da->d_name, db->d_name);
  28 }
  29
  30 struct dirsort_privates {
  31         long pos;
  32         struct dirent *directory_list;
  33         long number_of_entries;
  34         time_t mtime;
  35         DIR *source_directory;
  36         int fd;
  37 };
  38
  39 static void free_dirsort_privates(void **datap) {
  40         struct dirsort_privates *data = (struct dirsort_privates *) *datap;
  41         SAFE_FREE(data->directory_list);
  42         SAFE_FREE(data);
  43         *datap = NULL;
  44 }
  45
  46 static bool open_and_sort_dir (vfs_handle_struct *handle)
  47 {
  48         struct dirent *dp;
  49         struct stat dir_stat;
  50         long current_pos;
  51         struct dirsort_privates *data = NULL;
  52
  53         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
  54                                 return false);
  55
  56         data->number_of_entries = 0;
  57
  58         if (fstat(data->fd, &dir_stat) == 0) {
  59                 data->mtime = dir_stat.st_mtime;
  60         }
  61
  62         while (SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL)
  63                != NULL) {
  64                 data->number_of_entries++;
  65         }
  66
  67         /* Open the underlying directory and count the number of entries
  68            Skip back to the beginning as we'll read it again */
  69         SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
  70
  71         /* Set up an array and read the directory entries into it */
  72         SAFE_FREE(data->directory_list); /* destroy previous cache if needed */
  73         data->directory_list = (struct dirent *)SMB_MALLOC(
  74                 data->number_of_entries * sizeof(struct dirent));
  75         if (!data->directory_list) {
  76                 return false;
  77         }
  78         current_pos = data->pos;
  79         data->pos = 0;
  80         while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory,
  81                                           NULL)) != NULL) {
  82                 data->directory_list[data->pos++] = *dp;
  83         }
  84
  85         /* Sort the directory entries by name */
  86         data->pos = current_pos;
  87         TYPESAFE_QSORT(data->directory_list, data->number_of_entries, compare_dirent);
  88         return true;
  89 }
  90
  91 static DIR *dirsort_opendir(vfs_handle_struct *handle,
  92                                        const char *fname, const char *mask,
  93                                        uint32 attr)
  94 {
  95         struct dirsort_privates *data = NULL;
  96
  97         /* set up our private data about this directory */
  98         data = (struct dirsort_privates *)SMB_MALLOC(
  99                 sizeof(struct dirsort_privates));
 100
 101         if (!data) {
 102                 return NULL;
 103         }
 104
 105         data->directory_list = NULL;
 106         data->pos = 0;
 107
 108         /* Open the underlying directory and count the number of entries */
 109         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, fname, mask,
 110                                                       attr);
 111
 112         data->fd = dirfd(data->source_directory);
 113
 114         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 115                                 struct dirsort_privates, return NULL);
 116
 117         if (!open_and_sort_dir(handle)) {
 118                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 119                 return NULL;
 120         }
 121
 122         return data->source_directory;
 123 }
 124
 125 static DIR *dirsort_fdopendir(vfs_handle_struct *handle,
 126                                         files_struct *fsp,
 127                                         const char *mask,
 128                                         uint32 attr)
 129 {
 130         struct dirsort_privates *data = NULL;
 131
 132         /* set up our private data about this directory */
 133         data = (struct dirsort_privates *)SMB_MALLOC(
 134                 sizeof(struct dirsort_privates));
 135
 136         if (!data) {
 137                 return NULL;
 138         }
 139
 140         data->directory_list = NULL;
 141         data->pos = 0;
 142
 143         /* Open the underlying directory and count the number of entries */
 144         data->source_directory = SMB_VFS_NEXT_FDOPENDIR(handle, fsp, mask,
 145                                                       attr);
 146
 147         if (data->source_directory == NULL) {
 148                 SAFE_FREE(data);
 149                 return NULL;
 150         }
 151
 152         data->fd = dirfd(data->source_directory);
 153
 154         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 155                                 struct dirsort_privates, return NULL);
 156
 157         if (!open_and_sort_dir(handle)) {
 158                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 159                 /* fd is now closed. */
 160                 fsp->fh->fd = -1;
 161                 return NULL;
 162         }
 163
 164         return data->source_directory;
 165 }
 166
 167 static struct dirent *dirsort_readdir(vfs_handle_struct *handle,
 168                                           DIR *dirp,
 169                                           SMB_STRUCT_STAT *sbuf)
 170 {
 171         struct dirsort_privates *data = NULL;
 172         time_t current_mtime;
 173         struct stat dir_stat;
 174
 175         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 176                                 return NULL);
 177
 178         if (fstat(data->fd, &dir_stat) == -1) {
 179                 return NULL;
 180         }
 181
 182         current_mtime = dir_stat.st_mtime;
 183
 184         /* throw away cache and re-read the directory if we've changed */
 185         if (current_mtime > data->mtime) {
 186                 open_and_sort_dir(handle);
 187         }
 188
 189         if (data->pos >= data->number_of_entries) {
 190                 return NULL;
 191         }
 192
 193         return &data->directory_list[data->pos++];
 194 }
 195
 196 static void dirsort_seekdir(vfs_handle_struct *handle, DIR *dirp,
 197                             long offset)
 198 {
 199         struct dirsort_privates *data = NULL;
 200         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 201
 202         data->pos = offset;
 203 }
 204
 205 static long dirsort_telldir(vfs_handle_struct *handle, DIR *dirp)
 206 {
 207         struct dirsort_privates *data = NULL;
 208         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 209                                 return -1);
 210
 211         return data->pos;
 212 }
 213
 214 static void dirsort_rewinddir(vfs_handle_struct *handle, DIR *dirp)
 215 {
 216         struct dirsort_privates *data = NULL;
 217         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 218
 219         data->pos = 0;
 220 }
 221
 222 static struct vfs_fn_pointers vfs_dirsort_fns = {
 223         .opendir_fn = dirsort_opendir,
 224         .fdopendir_fn = dirsort_fdopendir,
 225         .readdir_fn = dirsort_readdir,
 226         .seekdir_fn = dirsort_seekdir,
 227         .telldir_fn = dirsort_telldir,
 228         .rewind_dir_fn = dirsort_rewinddir,
 229 };
 230
 231 NTSTATUS vfs_dirsort_init(void)
 232 {
 233         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 234                                 &vfs_dirsort_fns);
 235 }