source/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 void *a, const void *b) {
  24         const SMB_STRUCT_DIRENT *da = (const SMB_STRUCT_DIRENT *) a;
  25         const SMB_STRUCT_DIRENT *db = (const SMB_STRUCT_DIRENT *) b;
  26         return StrCaseCmp(da->d_name, db->d_name);
  27 }
  28
  29 struct dirsort_privates {
  30         long pos;
  31         SMB_STRUCT_DIRENT *directory_list;
  32         long number_of_entries;
  33         time_t mtime;
  34         SMB_STRUCT_DIR *source_directory;
  35         int fd;
  36 };
  37
  38 static void free_dirsort_privates(void **datap) {
  39         struct dirsort_privates *data = (struct dirsort_privates *) *datap;
  40         SAFE_FREE(data->directory_list);
  41         SAFE_FREE(data);
  42         *datap = NULL;
  43
  44         return;
  45 }
  46
  47 static void open_and_sort_dir (vfs_handle_struct *handle)
  48 {
  49         SMB_STRUCT_DIRENT *dp;
  50         struct stat dir_stat;
  51         long current_pos;
  52         struct dirsort_privates *data = NULL;
  53
  54         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
  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                 data->number_of_entries++;
  64         }
  65
  66         /* Open the underlying directory and count the number of entries
  67            Skip back to the beginning as we'll read it again */
  68         SMB_VFS_NEXT_REWINDDIR(handle, data->source_directory);
  69
  70         /* Set up an array and read the directory entries into it */
  71         SAFE_FREE(data->directory_list); /* destroy previous cache if needed */
  72         data->directory_list = (SMB_STRUCT_DIRENT *)SMB_MALLOC(
  73                 data->number_of_entries * sizeof(SMB_STRUCT_DIRENT));
  74         current_pos = data->pos;
  75         data->pos = 0;
  76         while ((dp = SMB_VFS_NEXT_READDIR(handle, data->source_directory))
  77                != NULL) {
  78                 data->directory_list[data->pos++] = *dp;
  79         }
  80
  81         /* Sort the directory entries by name */
  82         data->pos = current_pos;
  83         qsort(data->directory_list, data->number_of_entries,
  84               sizeof(SMB_STRUCT_DIRENT), compare_dirent);
  85 }
  86
  87 static SMB_STRUCT_DIR *dirsort_opendir(vfs_handle_struct *handle,
  88                                        const char *fname, const char *mask,
  89                                        uint32 attr)
  90 {
  91         struct dirsort_privates *data = NULL;
  92
  93         /* set up our private data about this directory */
  94         data = (struct dirsort_privates *)SMB_MALLOC(
  95                 sizeof(struct dirsort_privates));
  96
  97         data->directory_list = NULL;
  98         data->pos = 0;
  99
 100         /* Open the underlying directory and count the number of entries */
 101         data->source_directory = SMB_VFS_NEXT_OPENDIR(handle, fname, mask,
 102                                                       attr);
 103
 104         data->fd = dirfd(data->source_directory);
 105
 106         SMB_VFS_HANDLE_SET_DATA(handle, data, free_dirsort_privates,
 107                                 struct dirsort_privates, return NULL);
 108
 109         open_and_sort_dir(handle);
 110
 111         return data->source_directory;
 112 }
 113
 114 static SMB_STRUCT_DIRENT *dirsort_readdir(vfs_handle_struct *handle,
 115                                           SMB_STRUCT_DIR *dirp)
 116 {
 117         struct dirsort_privates *data = NULL;
 118         time_t current_mtime;
 119         struct stat dir_stat;
 120
 121         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 122                                 return NULL);
 123
 124         if (fstat(data->fd, &dir_stat) == -1) {
 125                 return NULL;
 126         }
 127
 128         current_mtime = dir_stat.st_mtime;
 129
 130         /* throw away cache and re-read the directory if we've changed */
 131         if (current_mtime > data->mtime) {
 132                 open_and_sort_dir(handle);
 133         }
 134
 135         if (data->pos >= data->number_of_entries) {
 136                 return NULL;
 137         }
 138
 139         return &data->directory_list[data->pos++];
 140 }
 141
 142 static void dirsort_seekdir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp,
 143                             long offset)
 144 {
 145         struct dirsort_privates *data = NULL;
 146         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 147
 148         data->pos = offset;
 149 }
 150
 151 static long dirsort_telldir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 152 {
 153         struct dirsort_privates *data = NULL;
 154         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates,
 155                                 return -1);
 156
 157         return data->pos;
 158 }
 159
 160 static void dirsort_rewinddir(vfs_handle_struct *handle, SMB_STRUCT_DIR *dirp)
 161 {
 162         struct dirsort_privates *data = NULL;
 163         SMB_VFS_HANDLE_GET_DATA(handle, data, struct dirsort_privates, return);
 164
 165         data->pos = 0;
 166 }
 167
 168 /* VFS operations structure */
 169
 170 static vfs_op_tuple dirsort_op_tuples[] = {
 171
 172     /* Directory operations */
 173
 174     {SMB_VFS_OP(dirsort_opendir),            SMB_VFS_OP_OPENDIR,
 175      SMB_VFS_LAYER_TRANSPARENT},
 176     {SMB_VFS_OP(dirsort_readdir),            SMB_VFS_OP_READDIR,
 177      SMB_VFS_LAYER_TRANSPARENT},
 178     {SMB_VFS_OP(dirsort_seekdir),            SMB_VFS_OP_SEEKDIR,
 179      SMB_VFS_LAYER_TRANSPARENT},
 180     {SMB_VFS_OP(dirsort_telldir),            SMB_VFS_OP_TELLDIR,
 181      SMB_VFS_LAYER_TRANSPARENT},
 182     {SMB_VFS_OP(dirsort_rewinddir),          SMB_VFS_OP_REWINDDIR,
 183      SMB_VFS_LAYER_TRANSPARENT},
 184
 185     {NULL,                                   SMB_VFS_OP_NOOP,
 186      SMB_VFS_LAYER_NOOP}
 187 };
 188
 189 NTSTATUS vfs_dirsort_init(void)
 190 {
 191         return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "dirsort",
 192                                 dirsort_op_tuples);
 193 }