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
  48         if (data->fsp) {
  49                 ret = fsp_stat(data->fsp);
  50                 mtime = data->fsp->fsp_name->st.st_ex_mtime;
  51         } else {
  52                 ret = SMB_VFS_STAT(handle->conn, data->smb_fname);
  53                 mtime = data->smb_fname->st.st_ex_mtime;
  54         }
  55
  56         if (ret == -1) {
  57                 return false;
  58         }
  59
  60         *ret_mtime = mtime;
  61
  62         return true;
  63 }
  64
  65 static bool open_and_sort_dir(vfs_handle_struct *handle,
  66                                 struct dirsort_privates *data)
  67 {
  68         uint32_t total_count = 0;
  69         /* This should be enough for most use cases */
  70         uint32_t dirent_allocated = 64;
  71         struct dirent *dp;
  72
  73         data->number_of_entries = 0;
  74
  75         if (get_sorted_dir_mtime(handle, data, &data->mtime) == false) {
  76                 return false;
  77         }
  78
  79         dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL);
  80         if (dp == NULL) {
  81                 return false;
  82         }
  83
  84         /* Set up an array and read the directory entries into it */
  85         TALLOC_FREE(data->directory_list); /* destroy previous cache if needed */
  86         data->directory_list = talloc_zero_array(data,
  87                                                  struct dirent,
  88                                                  dirent_allocated);
  89         if (data->directory_list == NULL) {
  90                 return false;
  91         }
  92
  93         do {
  94                 if (total_count >= dirent_allocated) {
  95                         struct dirent *dlist;
  96
  97                         /*
  98                          * Be memory friendly.
  99                          *
 100                          * We should not double the amount of memory. With a lot
 101                          * of files we reach easily 50MB, and doubling will
 102                          * get much bigger just for a few files more.
 103                          *
 104                          * For 200k files this means 50 memory reallocations.
 105                          */
 106                         dirent_allocated += 4096;
 107
 108                         dlist = talloc_realloc(data,
 109                                                data->directory_list,
 110                                                struct dirent,
 111                                                dirent_allocated);
 112                         if (dlist == NULL) {
 113                                 break;
 114                         }
 115                         data->directory_list = dlist;
 116                 }
 117                 data->directory_list[total_count] = *dp;
 118
 119                 total_count++;
 120                 dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL);
 121         } while (dp != NULL);
 122
 123         data->number_of_entries = total_count;
 124
 125         /* Sort the directory entries by name */
 126         TYPESAFE_QSORT(data->directory_list, data->number_of_entries, compare_dirent);
 127         return true;
 128 }
 129
 130 static DIR *dirsort_opendir(vfs_handle_struct *handle,
 131                                 const struct smb_filename *smb_fname,
 132                                 const char *mask,
 133                                 uint32_t attr)
 134 {
 135         struct dirsort_privates *list_head = NULL;
 136         struct dirsort_privates *data = NULL;
 137
 138         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 139                 /* Find the list head of all open directories. */
 140                 SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates,
 141                                 return NULL);
 142         }
 143
 144         /* set up our private data about this directory */
 145         data = talloc_zero(handle->conn, struct dirsort_privates);
 146         if (!data) {
 147                 return NULL;
 148         }
 149
 150         data->smb_fname = cp_smb_filename(data, smb_fname);
 151         if (data->smb_fname == NULL) {
 152                 TALLOC_FREE(data);
 153                 return NULL;
 154         }
 155
 156         if (ISDOT(data->smb_fname->base_name)) {
 157                 struct smb_filename *cwd_fname = vfs_GetWd(data, handle->conn);
 158                 if (cwd_fname == NULL) {
 159                         TALLOC_FREE(data);
 160                         return NULL;
 161                 }
 162                 TALLOC_FREE(data->smb_fname->base_name);
 163                 data->smb_fname->base_name = talloc_move(data->smb_fname,
 164                                                 &cwd_fname->base_name);
 165                 TALLOC_FREE(cwd_fname);
 166         }
 167
 168         /* Open the underlying directory and count the number of entries */
 169         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, smb_fname, mask,
 170                                                       attr);
 171
 172         if (data->source_directory == NULL) {
 173                 TALLOC_FREE(data);
 174                 return NULL;
 175         }
 176
 177         if (!open_and_sort_dir(handle, data)) {
 178                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 179                 TALLOC_FREE(data);
 180                 return NULL;
 181         }
 182
 183         /* Add to the private list of all open directories. */
 184         DLIST_ADD(list_head, data);
 185         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 186                                 struct dirsort_privates, return NULL);
 187
 188         return data->source_directory;
 189 }
 190
 191 static DIR *dirsort_fdopendir(vfs_handle_struct *handle,
 192                                         files_struct *fsp,
 193                                         const char *mask,
 194                                         uint32_t attr)
 195 {
 196         struct dirsort_privates *list_head = NULL;
 197         struct dirsort_privates *data = NULL;
 198
 199         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 200                 /* Find the list head of all open directories. */
 201                 SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates,
 202                                 return NULL);
 203         }
 204
 205         /* set up our private data about this directory */
 206         data = talloc_zero(handle->conn, struct dirsort_privates);
 207         if (!data) {
 208                 return NULL;
 209         }
 210
 211         data->fsp = fsp;
 212
 213         /* Open the underlying directory and count the number of entries */
 214         data->source_directory = SMB_VFS_NEXT_FDOPENDIR(handle, fsp, mask,
 215                                                       attr);
 216
 217         if (data->source_directory == NULL) {
 218                 TALLOC_FREE(data);
 219                 return NULL;
 220         }
 221
 222         if (!open_and_sort_dir(handle, data)) {
 223                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 224                 TALLOC_FREE(data);
 225                 /* fd is now closed. */
 226                 fsp->fh->fd = -1;
 227                 return NULL;
 228         }
 229
 230         /* Add to the private list of all open directories. */
 231         DLIST_ADD(list_head, data);
 232         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 233                                 struct dirsort_privates, return NULL);
 234
 235         return data->source_directory;
 236 }
 237
 238 static struct dirent *dirsort_readdir(vfs_handle_struct *handle,
 239                                           DIR *dirp,
 240                                           SMB_STRUCT_STAT *sbuf)
 241 {
 242         struct dirsort_privates *data = NULL;
 243         struct timespec current_mtime;
 244
 245         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 246                                 return NULL);
 247
 248         while(data && (data->source_directory != dirp)) {
 249                 data = data->next;
 250         }
 251         if (data == NULL) {
 252                 return NULL;
 253         }
 254
 255         if (get_sorted_dir_mtime(handle, data, &current_mtime) == false) {
 256                 return NULL;
 257         }
 258
 259         /* throw away cache and re-read the directory if we've changed */
 260         if (timespec_compare(&current_mtime, &data->mtime)) {
 261                 SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
 262                 open_and_sort_dir(handle, data);
 263         }
 264
 265         if (data->pos >= data->number_of_entries) {
 266                 return NULL;
 267         }
 268
 269         return &data->directory_list[data->pos++];
 270 }
 271
 272 static void dirsort_seekdir(vfs_handle_struct *handle, DIR *dirp,
 273                             long offset)
 274 {
 275         struct timespec current_mtime;
 276         struct dirsort_privates *data = NULL;
 277
 278         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 279
 280         /* Find the entry holding dirp. */
 281         while(data && (data->source_directory != dirp)) {
 282                 data = data->next;
 283         }
 284         if (data == NULL) {
 285                 return;
 286         }
 287         if (offset >= data->number_of_entries) {
 288                 return;
 289         }
 290         data->pos = offset;
 291
 292         if (get_sorted_dir_mtime(handle, data, &current_mtime) == false) {
 293                 return;
 294         }
 295
 296         if (timespec_compare(&current_mtime, &data->mtime)) {
 297                 /* Directory changed. We must re-read the
 298                    cache and search for the name that was
 299                    previously stored at the offset being
 300                    requested, otherwise after the re-sort
 301                    we will point to the wrong entry. The
 302                    OS/2 incremental delete code relies on
 303                    this. */
 304                 unsigned int i;
 305                 char *wanted_name = talloc_strdup(handle->conn,
 306                                         data->directory_list[offset].d_name);
 307                 if (wanted_name == NULL) {
 308                         return;
 309                 }
 310                 SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
 311                 open_and_sort_dir(handle, data);
 312                 /* Now search for where we were. */
 313                 data->pos = 0;
 314                 for (i = 0; i < data->number_of_entries; i++) {
 315                         if(strcmp(wanted_name, data->directory_list[i].d_name) == 0) {
 316                                 data->pos = i;
 317                                 break;
 318                         }
 319                 }
 320                 TALLOC_FREE(wanted_name);
 321         }
 322 }
 323
 324 static long dirsort_telldir(vfs_handle_struct *handle, DIR *dirp)
 325 {
 326         struct dirsort_privates *data = NULL;
 327         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 328                                 return -1);
 329
 330         /* Find the entry holding dirp. */
 331         while(data && (data->source_directory != dirp)) {
 332                 data = data->next;
 333         }
 334         if (data == NULL) {
 335                 return -1;
 336         }
 337         return data->pos;
 338 }
 339
 340 static void dirsort_rewinddir(vfs_handle_struct *handle, DIR *dirp)
 341 {
 342         struct dirsort_privates *data = NULL;
 343         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 344
 345         /* Find the entry holding dirp. */
 346         while(data && (data->source_directory != dirp)) {
 347                 data = data->next;
 348         }
 349         if (data == NULL) {
 350                 return;
 351         }
 352         data->pos = 0;
 353 }
 354
 355 static int dirsort_closedir(vfs_handle_struct *handle, DIR *dirp)
 356 {
 357         struct dirsort_privates *list_head = NULL;
 358         struct dirsort_privates *data = NULL;
 359         int ret;
 360
 361         SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates, return -1);
 362         /* Find the entry holding dirp. */
 363         for(data = list_head; data && (data->source_directory != dirp); data = data->next) {
 364                 ;
 365         }
 366         if (data == NULL) {
 367                 return -1;
 368         }
 369         /* Remove from the list and re-store the list head. */
 370         DLIST_REMOVE(list_head, data);
 371         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 372                                 struct dirsort_privates, return -1);
 373
 374         ret = SMB_VFS_NEXT_CLOSEDIR(handle, dirp);
 375         TALLOC_FREE(data);
 376         return ret;
 377 }
 378
 379 static struct vfs_fn_pointers vfs_dirsort_fns = {
 380         .opendir_fn = dirsort_opendir,
 381         .fdopendir_fn = dirsort_fdopendir,
 382         .readdir_fn = dirsort_readdir,
 383         .seekdir_fn = dirsort_seekdir,
 384         .telldir_fn = dirsort_telldir,
 385         .rewind_dir_fn = dirsort_rewinddir,
 386         .closedir_fn = dirsort_closedir,
 387 };
 388
 389 static_decl_vfs;
 390 NTSTATUS vfs_dirsort_init(TALLOC_CTX *ctx)
 391 {
 392         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 393                                 &vfs_dirsort_fns);
 394 }