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                 data->smb_fname->base_name = vfs_GetWd(data, handle->conn);
 158         }
 159
 160         /* Open the underlying directory and count the number of entries */
 161         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, smb_fname, mask,
 162                                                       attr);
 163
 164         if (data->source_directory == NULL) {
 165                 TALLOC_FREE(data);
 166                 return NULL;
 167         }
 168
 169         if (!open_and_sort_dir(handle, data)) {
 170                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 171                 TALLOC_FREE(data);
 172                 return NULL;
 173         }
 174
 175         /* Add to the private list of all open directories. */
 176         DLIST_ADD(list_head, data);
 177         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 178                                 struct dirsort_privates, return NULL);
 179
 180         return data->source_directory;
 181 }
 182
 183 static DIR *dirsort_fdopendir(vfs_handle_struct *handle,
 184                                         files_struct *fsp,
 185                                         const char *mask,
 186                                         uint32_t attr)
 187 {
 188         struct dirsort_privates *list_head = NULL;
 189         struct dirsort_privates *data = NULL;
 190
 191         if (SMB_VFS_HANDLE_TEST_DATA(handle)) {
 192                 /* Find the list head of all open directories. */
 193                 SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates,
 194                                 return NULL);
 195         }
 196
 197         /* set up our private data about this directory */
 198         data = talloc_zero(handle->conn, struct dirsort_privates);
 199         if (!data) {
 200                 return NULL;
 201         }
 202
 203         data->fsp = fsp;
 204
 205         /* Open the underlying directory and count the number of entries */
 206         data->source_directory = SMB_VFS_NEXT_FDOPENDIR(handle, fsp, mask,
 207                                                       attr);
 208
 209         if (data->source_directory == NULL) {
 210                 TALLOC_FREE(data);
 211                 return NULL;
 212         }
 213
 214         if (!open_and_sort_dir(handle, data)) {
 215                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 216                 TALLOC_FREE(data);
 217                 /* fd is now closed. */
 218                 fsp->fh->fd = -1;
 219                 return NULL;
 220         }
 221
 222         /* Add to the private list of all open directories. */
 223         DLIST_ADD(list_head, data);
 224         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 225                                 struct dirsort_privates, return NULL);
 226
 227         return data->source_directory;
 228 }
 229
 230 static struct dirent *dirsort_readdir(vfs_handle_struct *handle,
 231                                           DIR *dirp,
 232                                           SMB_STRUCT_STAT *sbuf)
 233 {
 234         struct dirsort_privates *data = NULL;
 235         struct timespec current_mtime;
 236
 237         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 238                                 return NULL);
 239
 240         while(data && (data->source_directory != dirp)) {
 241                 data = data->next;
 242         }
 243         if (data == NULL) {
 244                 return NULL;
 245         }
 246
 247         if (get_sorted_dir_mtime(handle, data, &current_mtime) == false) {
 248                 return NULL;
 249         }
 250
 251         /* throw away cache and re-read the directory if we've changed */
 252         if (timespec_compare(&current_mtime, &data->mtime)) {
 253                 SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
 254                 open_and_sort_dir(handle, data);
 255         }
 256
 257         if (data->pos >= data->number_of_entries) {
 258                 return NULL;
 259         }
 260
 261         return &data->directory_list[data->pos++];
 262 }
 263
 264 static void dirsort_seekdir(vfs_handle_struct *handle, DIR *dirp,
 265                             long offset)
 266 {
 267         struct timespec current_mtime;
 268         struct dirsort_privates *data = NULL;
 269
 270         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 271
 272         /* Find the entry holding dirp. */
 273         while(data && (data->source_directory != dirp)) {
 274                 data = data->next;
 275         }
 276         if (data == NULL) {
 277                 return;
 278         }
 279         if (offset >= data->number_of_entries) {
 280                 return;
 281         }
 282         data->pos = offset;
 283
 284         if (get_sorted_dir_mtime(handle, data, &current_mtime) == false) {
 285                 return;
 286         }
 287
 288         if (timespec_compare(&current_mtime, &data->mtime)) {
 289                 /* Directory changed. We must re-read the
 290                    cache and search for the name that was
 291                    previously stored at the offset being
 292                    requested, otherwise after the re-sort
 293                    we will point to the wrong entry. The
 294                    OS/2 incremental delete code relies on
 295                    this. */
 296                 unsigned int i;
 297                 char *wanted_name = talloc_strdup(handle->conn,
 298                                         data->directory_list[offset].d_name);
 299                 if (wanted_name == NULL) {
 300                         return;
 301                 }
 302                 SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
 303                 open_and_sort_dir(handle, data);
 304                 /* Now search for where we were. */
 305                 data->pos = 0;
 306                 for (i = 0; i < data->number_of_entries; i++) {
 307                         if(strcmp(wanted_name, data->directory_list[i].d_name) == 0) {
 308                                 data->pos = i;
 309                                 break;
 310                         }
 311                 }
 312                 TALLOC_FREE(wanted_name);
 313         }
 314 }
 315
 316 static long dirsort_telldir(vfs_handle_struct *handle, DIR *dirp)
 317 {
 318         struct dirsort_privates *data = NULL;
 319         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 320                                 return -1);
 321
 322         /* Find the entry holding dirp. */
 323         while(data && (data->source_directory != dirp)) {
 324                 data = data->next;
 325         }
 326         if (data == NULL) {
 327                 return -1;
 328         }
 329         return data->pos;
 330 }
 331
 332 static void dirsort_rewinddir(vfs_handle_struct *handle, DIR *dirp)
 333 {
 334         struct dirsort_privates *data = NULL;
 335         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 336
 337         /* Find the entry holding dirp. */
 338         while(data && (data->source_directory != dirp)) {
 339                 data = data->next;
 340         }
 341         if (data == NULL) {
 342                 return;
 343         }
 344         data->pos = 0;
 345 }
 346
 347 static int dirsort_closedir(vfs_handle_struct *handle, DIR *dirp)
 348 {
 349         struct dirsort_privates *list_head = NULL;
 350         struct dirsort_privates *data = NULL;
 351         int ret;
 352
 353         SMB_VFS_HANDLE_GET_DATA(handle, list_head, struct dirsort_privates, return -1);
 354         /* Find the entry holding dirp. */
 355         for(data = list_head; data && (data->source_directory != dirp); data = data->next) {
 356                 ;
 357         }
 358         if (data == NULL) {
 359                 return -1;
 360         }
 361         /* Remove from the list and re-store the list head. */
 362         DLIST_REMOVE(list_head, data);
 363         SMB_VFS_HANDLE_SET_DATA(handle, list_head, NULL,
 364                                 struct dirsort_privates, return -1);
 365
 366         ret = SMB_VFS_NEXT_CLOSEDIR(handle, dirp);
 367         TALLOC_FREE(data);
 368         return ret;
 369 }
 370
 371 static struct vfs_fn_pointers vfs_dirsort_fns = {
 372         .opendir_fn = dirsort_opendir,
 373         .fdopendir_fn = dirsort_fdopendir,
 374         .readdir_fn = dirsort_readdir,
 375         .seekdir_fn = dirsort_seekdir,
 376         .telldir_fn = dirsort_telldir,
 377         .rewind_dir_fn = dirsort_rewinddir,
 378         .closedir_fn = dirsort_closedir,
 379 };
 380
 381 static_decl_vfs;
 382 NTSTATUS vfs_dirsort_init(void)
 383 {
 384         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 385                                 &vfs_dirsort_fns);
 386 }