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         struct dirsort_privates *prev, *next;
  32         long pos;
  33         struct dirent *directory_list;
  34         unsigned int number_of_entries;
  35         struct timespec mtime;
  36         DIR *source_directory;
  37         files_struct *fsp; /* If open via FDOPENDIR. */
  38         struct smb_filename *smb_fname; /* If open via OPENDIR */
  39 };
  40
  41 static bool get_sorted_dir_mtime(vfs_handle_struct *handle,
  42                                 struct dirsort_privates *data,
  43                                 struct timespec *ret_mtime)
  44 {
  45         int ret;
  46         struct timespec mtime;
  47         NTSTATUS status;
  48
  49         if (data->fsp) {
  50                 status = vfs_stat_fsp(data->fsp);
  51                 if (!NT_STATUS_IS_OK(status)) {
  52                         return false;
  53                 }
  54                 mtime = data->fsp->fsp_name->st.st_ex_mtime;
  55         } else {
  56                 ret = SMB_VFS_STAT(handle->conn, data->smb_fname);
  57                 if (ret == -1) {
  58                         return false;
  59                 }
  60                 mtime = data->smb_fname->st.st_ex_mtime;
  61         }
  62
  63         *ret_mtime = mtime;
  64
  65         return true;
  66 }
  67
  68 static bool open_and_sort_dir(vfs_handle_struct *handle,
  69                                 struct dirsort_privates *data)
  70 {
  71         uint32_t total_count = 0;
  72         /* This should be enough for most use cases */
  73         uint32_t dirent_allocated = 64;
  74         struct dirent *dp;
  75
  76         data->number_of_entries = 0;
  77
  78         if (get_sorted_dir_mtime(handle, data, &data->mtime) == false) {
  79                 return false;
  80         }
  81
  82         dp = SMB_VFS_NEXT_READDIR(handle, data->fsp, data->source_directory);
  83         if (dp == NULL) {
  84                 return false;
  85         }
  86
  87         /* Set up an array and read the directory entries into it */
  88         TALLOC_FREE(data->directory_list); /* destroy previous cache if needed */
  89         data->directory_list = talloc_zero_array(data,
  90                                                  struct dirent,
  91                                                  dirent_allocated);
  92         if (data->directory_list == NULL) {
  93                 return false;
  94         }
  95
  96         do {
  97                 if (total_count >= dirent_allocated) {
  98                         struct dirent *dlist;
  99
 100                         /*
 101                          * Be memory friendly.
 102                          *
 103                          * We should not double the amount of memory. With a lot
 104                          * of files we reach easily 50MB, and doubling will
 105                          * get much bigger just for a few files more.
 106                          *
 107                          * For 200k files this means 50 memory reallocations.
 108                          */
 109                         dirent_allocated += 4096;
 110
 111                         dlist = talloc_realloc(data,
 112                                                data->directory_list,
 113                                                struct dirent,
 114                                                dirent_allocated);
 115                         if (dlist == NULL) {
 116                                 break;
 117                         }
 118                         data->directory_list = dlist;
 119                 }
 120                 data->directory_list[total_count] = *dp;
 121
 122                 total_count++;
 123                 dp = SMB_VFS_NEXT_READDIR(handle,
 124                                           data->fsp,
 125                                           data->source_directory);
 126         } while (dp != NULL);
 127
 128         data->number_of_entries = total_count;
 129
 130         /* Sort the directory entries by name */
 131         TYPESAFE_QSORT(data->directory_list, data->number_of_entries, compare_dirent);
 132         return true;
 133 }
 134
 135 static DIR *dirsort_fdopendir(vfs_handle_struct *handle,
 136                                         files_struct *fsp,
 137                                         const char *mask,
 138                                         uint32_t attr)
 139 {
 140         struct dirsort_privates *list_head = NULL;
 141         struct dirsort_privates *data = NULL;
 142
 143         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 144                 /* Find the list head of all open directories. */
 145                 SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates,
 146                                 return NULL);
 147         }
 148
 149         /* set up our private data about this directory */
 150         data = talloc_zero(handle->conn, struct dirsort_privates);
 151         if (!data) {
 152                 return NULL;
 153         }
 154
 155         data->fsp = fsp;
 156
 157         /* Open the underlying directory and count the number of entries */
 158         data->source_directory = SMB_VFS_NEXT_FDOPENDIR(handle, fsp, mask,
 159                                                       attr);
 160
 161         if (data->source_directory == NULL) {
 162                 TALLOC_FREE(data);
 163                 return NULL;
 164         }
 165
 166         if (!open_and_sort_dir(handle, data)) {
 167                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 168                 TALLOC_FREE(data);
 169                 /* fd is now closed. */
 170                 fsp_set_fd(fsp, -1);
 171                 return NULL;
 172         }
 173
 174         /* Add to the private list of all open directories. */
 175         DLIST_ADD(list_head, data);
 176         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 177                                 struct dirsort_privates, return NULL);
 178
 179         return data->source_directory;
 180 }
 181
 182 static struct dirent *dirsort_readdir(vfs_handle_struct *handle,
 183                                       struct files_struct *dirfsp,
 184                                       DIR *dirp)
 185 {
 186         struct dirsort_privates *data = NULL;
 187         struct timespec current_mtime;
 188
 189         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 190                                 return NULL);
 191
 192         while(data && (data->source_directory != dirp)) {
 193                 data = data->next;
 194         }
 195         if (data == NULL) {
 196                 return NULL;
 197         }
 198
 199         if (get_sorted_dir_mtime(handle, data, &current_mtime) == false) {
 200                 return NULL;
 201         }
 202
 203         /* throw away cache and re-read the directory if we've changed */
 204         if (timespec_compare(&current_mtime, &data->mtime)) {
 205                 SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
 206                 open_and_sort_dir(handle, data);
 207         }
 208
 209         if (data->pos >= data->number_of_entries) {
 210                 return NULL;
 211         }
 212
 213         return &data->directory_list[data->pos++];
 214 }
 215
 216 static void dirsort_rewinddir(vfs_handle_struct *handle, DIR *dirp)
 217 {
 218         struct dirsort_privates *data = NULL;
 219         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 220
 221         /* Find the entry holding dirp. */
 222         while(data && (data->source_directory != dirp)) {
 223                 data = data->next;
 224         }
 225         if (data == NULL) {
 226                 return;
 227         }
 228         data->pos = 0;
 229 }
 230
 231 static int dirsort_closedir(vfs_handle_struct *handle, DIR *dirp)
 232 {
 233         struct dirsort_privates *list_head = NULL;
 234         struct dirsort_privates *data = NULL;
 235         int ret;
 236
 237         SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates, return -1);
 238         /* Find the entry holding dirp. */
 239         for(data = list_head; data && (data->source_directory != dirp); data = data->next) {
 240                 ;
 241         }
 242         if (data == NULL) {
 243                 return -1;
 244         }
 245         /* Remove from the list and re-store the list head. */
 246         DLIST_REMOVE(list_head, data);
 247         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 248                                 struct dirsort_privates, return -1);
 249
 250         ret = SMB_VFS_NEXT_CLOSEDIR(handle, dirp);
 251         TALLOC_FREE(data);
 252         return ret;
 253 }
 254
 255 static struct vfs_fn_pointers vfs_dirsort_fns = {
 256         .fdopendir_fn = dirsort_fdopendir,
 257         .readdir_fn = dirsort_readdir,
 258         .rewind_dir_fn = dirsort_rewinddir,
 259         .closedir_fn = dirsort_closedir,
 260 };
 261
 262 static_decl_vfs;
 263 NTSTATUS vfs_dirsort_init(TALLOC_CTX *ctx)
 264 {
 265         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 266                                 &vfs_dirsort_fns);
 267 }