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
  23 static int compare_dirent (const SMB_STRUCT_DIRENT *da, const SMB_STRUCT_DIRENT *db)
  24 {
  25         return StrCaseCmp(da->d_name, db->d_name);
  26 }
  27
  28 struct dirsort_privates {
  29         long pos;
  30         SMB_STRUCT_DIRENT *directory_list;
  31         long number_of_entries;
  32         time_t mtime;
  33         SMB_STRUCT_DIR *source_directory;
  34         int fd;
  35 };
  36
  37 static void free_dirsort_privates(void **datap) {
  38         struct dirsort_privates *data = (struct dirsort_privates *) *datap;
  39         SAFE_FREE(data->directory_list);
  40         SAFE_FREE(data);
  41         *datap = NULL;
  42
  43         return;
  44 }
  45
  46 static bool open_and_sort_dir (vfs_handle_struct *handle)
  47 {
  48         SMB_STRUCT_DIRENT *dp;
  49         struct stat dir_stat;
  50         long current_pos;
  51         struct dirsort_privates *data = NULL;
  52
  53         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
  54                                 return false);
  55
  56         data->number_of_entries = 0;
  57
  58         if (fstat(data->fd, &dir_stat) == 0) {
  59                 data->mtime = dir_stat.st_mtime;
  60         }
  61
  62         while (SMB_VFS_NEXT_READDIR(handle, data->source_directory, NULL)
  63                != NULL) {
  64                 data->number_of_entries++;
  65         }
  66
  67         /* Open the underlying directory and count the number of entries
  68            Skip back to the beginning as we'll read it again */
  69         SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
  70
  71         /* Set up an array and read the directory entries into it */
  72         SAFE_FREE(data->directory_list); /* destroy previous cache if needed */
  73         data->directory_list = (SMB_STRUCT_DIRENT *)SMB_MALLOC(
  74                 data->number_of_entries * sizeof(SMB_STRUCT_DIRENT));
  75         if (!data->directory_list) {
  76                 return false;
  77         }
  78         current_pos = data->pos;
  79         data->pos = 0;
  80         while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory,
  81                                           NULL)) != NULL) {
  82                 data->directory_list[data->pos++] = *dp;
  83         }
  84
  85         /* Sort the directory entries by name */
  86         data->pos = current_pos;
  87         TYPESAFE_QSORT(data->directory_list, data->number_of_entries, compare_dirent);
  88         return true;
  89 }
  90
  91 static SMB_STRUCT_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 = (struct dirsort_privates *)SMB_MALLOC(
  99                 sizeof(struct dirsort_privates));
 100
 101         if (!data) {
 102                 return NULL;
 103         }
 104
 105         data->directory_list = NULL;
 106         data->pos = 0;
 107
 108         /* Open the underlying directory and count the number of entries */
 109         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, fname, mask,
 110                                                       attr);
 111
 112         data->fd = dirfd(data->source_directory);
 113
 114         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 115                                 struct dirsort_privates, return NULL);
 116
 117         if (!open_and_sort_dir(handle)) {
 118                 SMB_VFS_NEXT_CLOSEDIR(handle,data->source_directory);
 119                 return NULL;
 120         }
 121
 122         return data->source_directory;
 123 }
 124
 125 static SMB_STRUCT_DIRENT *dirsort_readdir(vfs_handle_struct *handle,
 126                                           SMB_STRUCT_DIR *dirp,
 127                                           SMB_STRUCT_STAT *sbuf)
 128 {
 129         struct dirsort_privates *data = NULL;
 130         time_t current_mtime;
 131         struct stat dir_stat;
 132
 133         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 134                                 return NULL);
 135
 136         if (fstat(data->fd, &dir_stat) == -1) {
 137                 return NULL;
 138         }
 139
 140         current_mtime = dir_stat.st_mtime;
 141
 142         /* throw away cache and re-read the directory if we've changed */
 143         if (current_mtime > data->mtime) {
 144                 open_and_sort_dir(handle);
 145         }
 146
 147         if (data->pos >= data->number_of_entries) {
 148                 return NULL;
 149         }
 150
 151         return &data->directory_list[data->pos++];
 152 }
 153
 154 static void dirsort_seekdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp,
 155                             long offset)
 156 {
 157         struct dirsort_privates *data = NULL;
 158         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 159
 160         data->pos = offset;
 161 }
 162
 163 static long dirsort_telldir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 164 {
 165         struct dirsort_privates *data = NULL;
 166         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 167                                 return -1);
 168
 169         return data->pos;
 170 }
 171
 172 static void dirsort_rewinddir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 173 {
 174         struct dirsort_privates *data = NULL;
 175         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 176
 177         data->pos = 0;
 178 }
 179
 180 static struct vfs_fn_pointers vfs_dirsort_fns = {
 181         .opendir = dirsort_opendir,
 182         .readdir = dirsort_readdir,
 183         .seekdir = dirsort_seekdir,
 184         .telldir = dirsort_telldir,
 185         .rewind_dir = dirsort_rewinddir,
 186 };
 187
 188 NTSTATUS vfs_dirsort_init(void)
 189 {
 190         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 191                                 &vfs_dirsort_fns);
 192 }