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