source/smbd/notify_hash.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 3.0
   4    change notify handling - hash based implementation
   5    Copyright (C) Jeremy Allison 1994-1998
   6    Copyright (C) Andrew Tridgell 2000
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24
  25 extern int DEBUGLEVEL;
  26
  27
  28 struct change_data {
  29         time_t last_check_time; /* time we last checked this entry */
  30         time_t modify_time; /* Info from the directory we're monitoring. */
  31         time_t status_time; /* Info from the directory we're monitoring. */
  32         time_t total_time; /* Total time of all directory entries - don't care if it wraps. */
  33         unsigned int num_entries; /* Zero or the number of files in the directory. */
  34 };
  35
  36
  37 /****************************************************************************
  38  Create the hash we will use to determine if the contents changed.
  39 *****************************************************************************/
  40 static BOOL notify_hash(connection_struct *conn, char *path, uint32 flags,
  41                         struct change_data *data, struct change_data *old_data)
  42 {
  43         SMB_STRUCT_STAT st;
  44         pstring full_name;
  45         char *p;
  46         char *fname;
  47         size_t remaining_len;
  48         size_t fullname_len;
  49         void *dp;
  50
  51         ZERO_STRUCTP(data);
  52
  53         if(vfs_stat(conn,path, &st) == -1) return False;
  54
  55         data->modify_time = st.st_mtime;
  56         data->status_time = st.st_ctime;
  57
  58         if (old_data) {
  59                 /*
  60                  * Shortcut to avoid directory scan if the time
  61                  * has changed - we always must return true then.
  62                  */
  63                 if (old_data->modify_time != data->modify_time ||
  64                         old_data->status_time != data->status_time ) {
  65                                 return True;
  66                 }
  67         }
  68
  69         /*
  70          * If we are to watch for changes that are only stored
  71          * in inodes of files, not in the directory inode, we must
  72          * scan the directory and produce a unique identifier with
  73          * which we can determine if anything changed. We use the
  74          * modify and change times from all the files in the
  75          * directory, added together (ignoring wrapping if it's
  76          * larger than the max time_t value).
  77          */
  78
  79         if (!(flags & (FILE_NOTIFY_CHANGE_SIZE|FILE_NOTIFY_CHANGE_LAST_WRITE))) return True;
  80
  81         dp = OpenDir(conn, path, True);
  82         if (dp == NULL) return False;
  83
  84         data->num_entries = 0;
  85
  86         pstrcpy(full_name, path);
  87         pstrcat(full_name, "/");
  88
  89         fullname_len = strlen(full_name);
  90         remaining_len = sizeof(full_name) - fullname_len - 1;
  91         p = &full_name[fullname_len];
  92
  93         while ((fname = ReadDirName(dp))) {
  94                 if(strequal(fname, ".") || strequal(fname, "..")) continue;
  95
  96                 data->num_entries++;
  97                 safe_strcpy(p, fname, remaining_len);
  98
  99                 ZERO_STRUCT(st);
 100
 101                 /*
 102                  * Do the stat - but ignore errors.
 103                  */
 104                 vfs_stat(conn,full_name, &st);
 105                 data->total_time += (st.st_mtime + st.st_ctime);
 106         }
 107
 108         CloseDir(dp);
 109
 110         return True;
 111 }
 112
 113
 114 /****************************************************************************
 115 register a change notify request
 116 *****************************************************************************/
 117 static void *hash_register_notify(connection_struct *conn, char *path, uint32 flags)
 118 {
 119         struct change_data data;
 120
 121         if (!notify_hash(conn, path, flags, &data, NULL)) return NULL;
 122
 123         data.last_check_time = time(NULL);
 124
 125         return (void *)memdup(&data, sizeof(data));
 126 }
 127
 128 /****************************************************************************
 129  Check if a change notify should be issued.
 130  A time of zero means instantaneous check - don't modify the last check time.
 131 *****************************************************************************/
 132 static BOOL hash_check_notify(connection_struct *conn, uint16 vuid, char *path, uint32 flags, void *datap, time_t t)
 133 {
 134         struct change_data *data = (struct change_data *)datap;
 135         struct change_data data2;
 136
 137         if (t && t < data->last_check_time + lp_change_notify_timeout()) return False;
 138
 139         if (!become_user(conn,vuid)) return True;
 140         if (!become_service(conn,True)) {
 141                 unbecome_user();
 142                 return True;
 143         }
 144
 145         if (!notify_hash(conn, path, flags, &data2, data) ||
 146             data2.modify_time != data->modify_time ||
 147             data2.status_time != data->status_time ||
 148             data2.total_time != data->total_time ||
 149             data2.num_entries != data->num_entries) {
 150                 unbecome_user();
 151                 return True;
 152         }
 153
 154         if (t)
 155                 data->last_check_time = t;
 156
 157         unbecome_user();
 158
 159         return False;
 160 }
 161
 162 /****************************************************************************
 163 remove a change notify data structure
 164 *****************************************************************************/
 165 static void hash_remove_notify(void *datap)
 166 {
 167         SAFE_FREE(datap);
 168 }
 169
 170
 171 /****************************************************************************
 172 setup hash based change notify
 173 ****************************************************************************/
 174 struct cnotify_fns *hash_notify_init(void)
 175 {
 176         static struct cnotify_fns cnotify;
 177
 178         cnotify.register_notify = hash_register_notify;
 179         cnotify.check_notify = hash_check_notify;
 180         cnotify.remove_notify = hash_remove_notify;
 181         cnotify.select_time = lp_change_notify_timeout();
 182
 183         return &cnotify;
 184 }
 185
 186
 187 /*
 188   change_notify_reply_packet(cnbp->request_buf,ERRSRV,ERRaccess);
 189   change_notify_reply_packet(cnbp->request_buf,0,NT_STATUS_NOTIFY_ENUM_DIR);
 190
 191   chain_size = 0;
 192   file_chain_reset();
 193
 194   uint16 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 195   SVAL(cnbp->request_buf,smb_uid);
 196 */