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