root/source4/ntvfs/posix/pvfs_wait.c

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DEFINITIONS

This source file includes following definitions.
  1. pvfs_async_setup
  2. pvfs_wait_dispatch
  3. pvfs_wait_timeout
  4. pvfs_wait_destructor
  5. pvfs_wait_message
  6. pvfs_cancel

   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 "smbd/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 messaging_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,
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  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 messaging_context *msg,
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  60                                void *private_data, uint32_t msg_type,
  61                                struct server_id src, DATA_BLOB *data)
  62 {
  63         struct pvfs_wait *pwait = talloc_get_type(private_data,
  64                                                   struct pvfs_wait);
  65         struct ntvfs_request *req;
  66         void *p = NULL;
  67 
  68         /* we need to check that this one is for us. See
  69            messaging_send_ptr() for the other side of this.
  70          */
  71         if (data->length == sizeof(void *)) {
  72                 void **pp;
  73                 pp = (void **)data->data;
  74                 p = *pp;
  75         }
  76         if (p == NULL || p != pwait->private_data) {
  77                 return;
  78         }
  79 
  80         pwait->reason = PVFS_WAIT_EVENT;
  81 
  82         /* the extra reference here is to ensure that the req
  83            structure is not destroyed when the async request reply is
  84            sent, which would cause problems with the other ntvfs
  85            modules above us */
  86         req = talloc_reference(msg, pwait->req);
  87         ntvfs_async_setup(pwait->req, pwait);
  88         talloc_unlink(msg, req);
  89 }
  90 
  91 
  92 /*
  93   receive a timeout on a message wait
  94 */
  95 static void pvfs_wait_timeout(struct tevent_context *ev, 
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  96                               struct tevent_timer *te, struct timeval t,
  97                               void *private_data)
  98 {
  99         struct pvfs_wait *pwait = talloc_get_type(private_data,
 100                                                   struct pvfs_wait);
 101         struct ntvfs_request *req = pwait->req;
 102 
 103         pwait->reason = PVFS_WAIT_TIMEOUT;
 104 
 105         talloc_increase_ref_count(req);
 106         ntvfs_async_setup(pwait->req, pwait);
 107         talloc_free(req);
 108 }
 109 
 110 
 111 /*
 112   destroy a pending wait
 113  */
 114 static int pvfs_wait_destructor(struct pvfs_wait *pwait)
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 115 {
 116         if (pwait->msg_type != -1) {
 117                 messaging_deregister(pwait->msg_ctx, pwait->msg_type, pwait);
 118         }
 119         DLIST_REMOVE(pwait->pvfs->wait_list, pwait);
 120         return 0;
 121 }
 122 
 123 /*
 124   setup a request to wait on a message of type msg_type, with a
 125   timeout (given as an expiry time)
 126 
 127   the return value is a handle. To stop waiting talloc_free this
 128   handle.
 129 
 130   if msg_type == -1 then no message is registered, and it is assumed
 131   that the caller handles any messaging setup needed
 132 */
 133 struct pvfs_wait *pvfs_wait_message(struct pvfs_state *pvfs,
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 134                                     struct ntvfs_request *req,
 135                                     int msg_type,
 136                                     struct timeval end_time,
 137                                     void (*fn)(void *, enum pvfs_wait_notice),
 138                                     void *private_data)
 139 {
 140         struct pvfs_wait *pwait;
 141 
 142         pwait = talloc(pvfs, struct pvfs_wait);
 143         if (pwait == NULL) {
 144                 return NULL;
 145         }
 146 
 147         pwait->private_data = private_data;
 148         pwait->handler = fn;
 149         pwait->msg_ctx = pvfs->ntvfs->ctx->msg_ctx;
 150         pwait->ev = pvfs->ntvfs->ctx->event_ctx;
 151         pwait->msg_type = msg_type;
 152         pwait->req = talloc_reference(pwait, req);
 153         pwait->pvfs = pvfs;
 154 
 155         if (!timeval_is_zero(&end_time)) {
 156                 /* setup a timer */
 157                 event_add_timed(pwait->ev, pwait, end_time, pvfs_wait_timeout, pwait);
 158         }
 159 
 160         /* register with the messaging subsystem for this message
 161            type */
 162         if (msg_type != -1) {
 163                 messaging_register(pwait->msg_ctx,
 164                                    pwait,
 165                                    msg_type,
 166                                    pvfs_wait_dispatch);
 167         }
 168 
 169         /* tell the main smb server layer that we will be replying 
 170            asynchronously */
 171         req->async_states->state |= NTVFS_ASYNC_STATE_ASYNC;
 172 
 173         DLIST_ADD(pvfs->wait_list, pwait);
 174 
 175         /* make sure we cleanup the timer and message handler */
 176         talloc_set_destructor(pwait, pvfs_wait_destructor);
 177 
 178         return pwait;
 179 }
 180 
 181 
 182 /*
 183   cancel an outstanding async request
 184 */
 185 NTSTATUS pvfs_cancel(struct ntvfs_module_context *ntvfs, struct ntvfs_request *req)
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 186 {
 187         struct pvfs_state *pvfs = talloc_get_type(ntvfs->private_data,
 188                                   struct pvfs_state);
 189         struct pvfs_wait *pwait;
 190 
 191         for (pwait=pvfs->wait_list;pwait;pwait=pwait->next) {
 192                 if (pwait->req == req) {
 193                         /* trigger a cancel on the request */
 194                         pwait->reason = PVFS_WAIT_CANCEL;
 195                         ntvfs_async_setup(pwait->req, pwait);
 196                         return NT_STATUS_OK;
 197                 }
 198         }
 199 
 200         return NT_STATUS_DOS(ERRDOS, ERRcancelviolation);
 201 }

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