source/smbd/notify.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 3.0
   4    change notify handling
   5    Copyright (C) Andrew Tridgell 2000
   6    Copyright (C) Jeremy Allison 1994-1998
   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 static struct cnotify_fns *cnotify;
  28
  29 /****************************************************************************
  30  This is the structure to queue to implement NT change
  31  notify. It consists of smb_size bytes stored from the
  32  transact command (to keep the mid, tid etc around).
  33  Plus the fid to examine and notify private data
  34 *****************************************************************************/
  35
  36 struct change_notify {
  37         struct change_notify *next, *prev;
  38         files_struct *fsp;
  39         connection_struct *conn;
  40         uint32 flags;
  41         char request_buf[smb_size];
  42         void *change_data;
  43 };
  44
  45 static struct change_notify *change_notify_list;
  46
  47 /****************************************************************************
  48  Setup the common parts of the return packet and send it.
  49 *****************************************************************************/
  50 static void change_notify_reply_packet(char *inbuf, uint32 error_code)
  51 {
  52         char outbuf[smb_size+38];
  53
  54         memset(outbuf, '\0', sizeof(outbuf));
  55         construct_reply_common(inbuf, outbuf);
  56
  57         /*
  58          * If we're returning a 'too much in the directory changed' we need to
  59          * set this is an NT error status flags. If we don't then the (probably
  60          * untested) code in the NT redirector has a bug in that it doesn't re-issue
  61          * the change notify.... Ah - I *love* it when I get so deeply into this I
  62          * can even determine how MS failed to test stuff and why.... :-). JRA.
  63          */
  64
  65         SSVAL(outbuf,smb_flg2, SVAL(outbuf,smb_flg2) | FLAGS2_32_BIT_ERROR_CODES);
  66         ERROR(0,error_code);
  67
  68         /*
  69          * Seems NT needs a transact command with an error code
  70          * in it. This is a longer packet than a simple error.
  71          */
  72         set_message(outbuf,18,0,False);
  73
  74         if (!send_smb(smbd_server_fd(),outbuf))
  75                 exit_server("change_notify_reply_packet: send_smb failed.\n");
  76 }
  77
  78 /****************************************************************************
  79 remove an entry from the list and free it, also closing any
  80 directory handle if necessary
  81 Notice the horrible stuff we have to do because this is a singly linked list.
  82 *****************************************************************************/
  83 static void change_notify_remove(struct change_notify *cnbp)
  84 {
  85         cnotify->remove_notify(cnbp->change_data);
  86         DLIST_REMOVE(change_notify_list, cnbp);
  87         ZERO_STRUCTP(cnbp);
  88         free(cnbp);
  89 }
  90
  91
  92 /****************************************************************************
  93  Delete entries by fnum from the change notify pending queue.
  94 *****************************************************************************/
  95 void remove_pending_change_notify_requests_by_fid(files_struct *fsp)
  96 {
  97         struct change_notify *cnbp, *next;
  98
  99         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 100                 next=cnbp->next;
 101                 if (cnbp->fsp->fnum == fsp->fnum) {
 102                         change_notify_remove(cnbp);
 103                 }
 104         }
 105 }
 106
 107 /****************************************************************************
 108  Delete entries by mid from the change notify pending queue. Always send reply.
 109 *****************************************************************************/
 110 void remove_pending_change_notify_requests_by_mid(int mid)
 111 {
 112         struct change_notify *cnbp, *next;
 113
 114         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 115                 next=cnbp->next;
 116                 if(SVAL(cnbp->request_buf,smb_mid) == mid) {
 117                         change_notify_reply_packet(cnbp->request_buf,NT_STATUS_CANCELLED);
 118                         change_notify_remove(cnbp);
 119                 }
 120         }
 121 }
 122
 123 /****************************************************************************
 124  Delete entries by filename and cnum from the change notify pending queue.
 125  Always send reply.
 126 *****************************************************************************/
 127 void remove_pending_change_notify_requests_by_filename(files_struct *fsp)
 128 {
 129         struct change_notify *cnbp, *next;
 130
 131         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 132                 next=cnbp->next;
 133                 /*
 134                  * We know it refers to the same directory if the connection number and
 135                  * the filename are identical.
 136                  */
 137                 if((cnbp->fsp->conn == fsp->conn) && strequal(cnbp->fsp->fsp_name,fsp->fsp_name)) {
 138                         change_notify_reply_packet(cnbp->request_buf,NT_STATUS_CANCELLED);
 139                         change_notify_remove(cnbp);
 140                 }
 141         }
 142 }
 143
 144 /****************************************************************************
 145  Return true if there are pending change notifies.
 146 ****************************************************************************/
 147 int change_notify_timeout(void)
 148 {
 149         return cnotify->select_time;
 150 }
 151
 152 /****************************************************************************
 153  Process the change notify queue. Note that this is only called as root.
 154  Returns True if there are still outstanding change notify requests on the
 155  queue.
 156 *****************************************************************************/
 157 BOOL process_pending_change_notify_queue(time_t t)
 158 {
 159         struct change_notify *cnbp, *next;
 160         uint16 vuid;
 161
 162         for (cnbp=change_notify_list; cnbp; cnbp=next) {
 163                 next=cnbp->next;
 164
 165                 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID : SVAL(cnbp->request_buf,smb_uid);
 166
 167                 if (cnotify->check_notify(cnbp->conn, vuid, cnbp->fsp->fsp_name, cnbp->flags, cnbp->change_data, t)) {
 168                         change_notify_reply_packet(cnbp->request_buf,STATUS_NOTIFY_ENUM_DIR);
 169                         change_notify_remove(cnbp);
 170                 }
 171         }
 172
 173         return (change_notify_list != NULL);
 174 }
 175
 176 /****************************************************************************
 177    * Now queue an entry on the notify change list.
 178    * We only need to save smb_size bytes from this incoming packet
 179    * as we will always by returning a 'read the directory yourself'
 180    * error.
 181 ****************************************************************************/
 182 BOOL change_notify_set(char *inbuf, files_struct *fsp, connection_struct *conn, uint32 flags)
 183 {
 184         struct change_notify *cnbp;
 185
 186         if((cnbp = (struct change_notify *)malloc(sizeof(*cnbp))) == NULL) {
 187                 DEBUG(0,("call_nt_transact_notify_change: malloc fail !\n" ));
 188                 return -1;
 189         }
 190
 191         ZERO_STRUCTP(cnbp);
 192
 193         memcpy(cnbp->request_buf, inbuf, smb_size);
 194         cnbp->fsp = fsp;
 195         cnbp->conn = conn;
 196         cnbp->flags = flags;
 197         cnbp->change_data = cnotify->register_notify(conn, fsp->fsp_name, flags);
 198
 199         if (!cnbp->change_data) {
 200                 free(cnbp);
 201                 return False;
 202         }
 203
 204         DLIST_ADD(change_notify_list, cnbp);
 205
 206         return True;
 207 }
 208
 209
 210 /****************************************************************************
 211 initialise the change notify subsystem
 212 ****************************************************************************/
 213 BOOL init_change_notify(void)
 214 {
 215 #if HAVE_KERNEL_CHANGE_NOTIFY
 216         cnotify = kernel_notify_init();
 217 #endif
 218         if (!cnotify) cnotify = hash_notify_init();
 219
 220         if (!cnotify) {
 221                 DEBUG(0,("Failed to init change notify system\n"));
 222                 return False;
 223         }
 224
 225         return True;
 226 }