source4/ntvfs/posix/pvfs_wait.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    POSIX NTVFS backend - async request wait routines
   5
   6    Copyright (C) Andrew Tridgell 2004
   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 3 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, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "lib/events/events.h"
  24 #include "../lib/util/dlinklist.h"
  25 #include "vfs_posix.h"
  26 #include "samba/service_stream.h"
  27 #include "lib/messaging/irpc.h"
  28
  29 /* the context for a single wait instance */
  30 struct pvfs_wait {
  31         struct pvfs_wait *next, *prev;
  32         struct pvfs_state *pvfs;
  33         void (*handler)(void *, enum pvfs_wait_notice);
  34         void *private_data;
  35         int msg_type;
  36         struct imessaging_context *msg_ctx;
  37         struct tevent_context *ev;
  38         struct ntvfs_request *req;
  39         enum pvfs_wait_notice reason;
  40 };
  41
  42 /*
  43   called from the ntvfs layer when we have requested setup of an async
  44   call.  this ensures that async calls runs with the right state of
  45   previous ntvfs handlers in the chain (such as security context)
  46 */
  47 NTSTATUS pvfs_async_setup(struct ntvfs_module_context *ntvfs,
  48                           struct ntvfs_request *req, void *private_data)
  49 {
  50         struct pvfs_wait *pwait = talloc_get_type(private_data,
  51                                                   struct pvfs_wait);
  52         pwait->handler(pwait->private_data, pwait->reason);
  53         return NT_STATUS_OK;
  54 }
  55
  56 /*
  57   receive a completion message for a wait
  58 */
  59 static void pvfs_wait_dispatch(struct imessaging_context *msg,
  60                                void *private_data,
  61                                uint32_t msg_type,
  62                                struct server_id src,
  63                                size_t num_fds,
  64                                int *fds,
  65                                DATA_BLOB *data)
  66 {
  67         struct pvfs_wait *pwait = talloc_get_type(private_data,
  68                                                   struct pvfs_wait);
  69         struct ntvfs_request *req;
  70         void *p = NULL;
  71
  72         if (num_fds != 0) {
  73                 DBG_WARNING("Received %zu fds, ignoring message\n", num_fds);
  74                 return;
  75         }
  76
  77         /* we need to check that this one is for us. See
  78            imessaging_send_ptr() for the other side of this.
  79          */
  80         if (data->length == sizeof(void *)) {
  81                 void **pp;
  82                 pp = (void **)data->data;
  83                 p = *pp;
  84         }
  85         if (p == NULL || p != pwait->private_data) {
  86                 return;
  87         }
  88
  89         pwait->reason = PVFS_WAIT_EVENT;
  90
  91         /* the extra reference here is to ensure that the req
  92            structure is not destroyed when the async request reply is
  93            sent, which would cause problems with the other ntvfs
  94            modules above us */
  95         req = talloc_reference(msg, pwait->req);
  96         ntvfs_async_setup(pwait->req, pwait);
  97         talloc_unlink(msg, req);
  98 }
  99
 100
 101 /*
 102   receive a timeout on a message wait
 103 */
 104 static void pvfs_wait_timeout(struct tevent_context *ev,
 105                               struct tevent_timer *te, struct timeval t,
 106                               void *private_data)
 107 {
 108         struct pvfs_wait *pwait = talloc_get_type(private_data,
 109                                                   struct pvfs_wait);
 110         struct ntvfs_request *req = pwait->req;
 111
 112         pwait->reason = PVFS_WAIT_TIMEOUT;
 113
 114         req = talloc_reference(ev, req);
 115         if (req != NULL) {
 116                 ntvfs_async_setup(req, pwait);
 117                 talloc_unlink(ev, req);
 118         }
 119 }
 120
 121
 122 /*
 123   destroy a pending wait
 124  */
 125 static int pvfs_wait_destructor(struct pvfs_wait *pwait)
 126 {
 127         if (pwait->msg_type != -1) {
 128                 imessaging_deregister(pwait->msg_ctx, pwait->msg_type, pwait);
 129         }
 130         DLIST_REMOVE(pwait->pvfs->wait_list, pwait);
 131         return 0;
 132 }
 133
 134 /*
 135   setup a request to wait on a message of type msg_type, with a
 136   timeout (given as an expiry time)
 137
 138   the return value is a handle. To stop waiting talloc_free this
 139   handle.
 140
 141   if msg_type == -1 then no message is registered, and it is assumed
 142   that the caller handles any messaging setup needed
 143 */
 144 struct pvfs_wait *pvfs_wait_message(struct pvfs_state *pvfs,
 145                                     struct ntvfs_request *req,
 146                                     int msg_type,
 147                                     struct timeval end_time,
 148                                     void (*fn)(void *, enum pvfs_wait_notice),
 149                                     void *private_data)
 150 {
 151         struct pvfs_wait *pwait;
 152
 153         pwait = talloc(pvfs, struct pvfs_wait);
 154         if (pwait == NULL) {
 155                 return NULL;
 156         }
 157
 158         pwait->private_data = private_data;
 159         pwait->handler = fn;
 160         pwait->msg_ctx = pvfs->ntvfs->ctx->msg_ctx;
 161         pwait->ev = pvfs->ntvfs->ctx->event_ctx;
 162         pwait->msg_type = msg_type;
 163         pwait->req = talloc_reference(pwait, req);
 164         pwait->pvfs = pvfs;
 165
 166         if (!timeval_is_zero(&end_time)) {
 167                 /* setup a timer */
 168                 tevent_add_timer(pwait->ev, pwait, end_time, pvfs_wait_timeout, pwait);
 169         }
 170
 171         /* register with the messaging subsystem for this message
 172            type */
 173         if (msg_type != -1) {
 174                 imessaging_register(pwait->msg_ctx,
 175                                    pwait,
 176                                    msg_type,
 177                                    pvfs_wait_dispatch);
 178         }
 179
 180         /* tell the main smb server layer that we will be replying
 181            asynchronously */
 182         req->async_states->state |= NTVFS_ASYNC_STATE_ASYNC;
 183
 184         DLIST_ADD(pvfs->wait_list, pwait);
 185
 186         /* make sure we cleanup the timer and message handler */
 187         talloc_set_destructor(pwait, pvfs_wait_destructor);
 188
 189         return pwait;
 190 }
 191
 192
 193 /*
 194   cancel an outstanding async request
 195 */
 196 NTSTATUS pvfs_cancel(struct ntvfs_module_context *ntvfs, struct ntvfs_request *req)
 197 {
 198         struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
 199                                   struct pvfs_state);
 200         struct pvfs_wait *pwait;
 201
 202         for (pwait=pvfs->wait_list;pwait;pwait=pwait->next) {
 203                 if (pwait->req == req) {
 204                         /* trigger a cancel on the request */
 205                         pwait->reason = PVFS_WAIT_CANCEL;
 206                         ntvfs_async_setup(pwait->req, pwait);
 207                         return NT_STATUS_OK;
 208                 }
 209         }
 210
 211         return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
 212 }