Sweden-Number/server/async.c

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/*
* Server-side async I/O support
*
* Copyright (C) 2007 Alexandre Julliard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include "ntstatus.h"
#define WIN32_NO_STATUS
#include "windef.h"
#include "winternl.h"
#include "object.h"
#include "file.h"
#include "request.h"
#include "process.h"
#include "handle.h"
struct async
{
struct object obj; /* object header */
struct thread *thread; /* owning thread */
struct list queue_entry; /* entry in async queue list */
struct list process_entry; /* entry in process list */
struct async_queue *queue; /* queue containing this async */
struct fd *fd; /* fd associated with an unqueued async */
struct timeout_user *timeout;
unsigned int timeout_status; /* status to report upon timeout */
struct event *event;
async_data_t data; /* data for async I/O call */
struct iosb *iosb; /* I/O status block */
obj_handle_t wait_handle; /* pre-allocated wait handle */
unsigned int initial_status; /* status returned from initial request */
unsigned int signaled :1;
unsigned int pending :1; /* request successfully queued, but pending */
unsigned int direct_result :1;/* a flag if we're passing result directly from request instead of APC */
unsigned int alerted :1; /* fd is signaled, but we are waiting for client-side I/O */
unsigned int terminated :1; /* async has been terminated */
unsigned int canceled :1; /* have we already queued cancellation for this async? */
unsigned int unknown_status :1; /* initial status is not known yet */
unsigned int blocking :1; /* async is blocking */
struct completion *completion; /* completion associated with fd */
apc_param_t comp_key; /* completion key associated with fd */
unsigned int comp_flags; /* completion flags */
async_completion_callback completion_callback; /* callback to be called on completion */
void *completion_callback_private; /* argument to completion_callback */
};
static void async_dump( struct object *obj, int verbose );
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static int async_signaled( struct object *obj, struct wait_queue_entry *entry );
static void async_satisfied( struct object * obj, struct wait_queue_entry *entry );
static void async_destroy( struct object *obj );
static const struct object_ops async_ops =
{
sizeof(struct async), /* size */
&no_type, /* type */
async_dump, /* dump */
2015-05-08 10:32:06 +02:00
add_queue, /* add_queue */
remove_queue, /* remove_queue */
async_signaled, /* signaled */
async_satisfied, /* satisfied */
no_signal, /* signal */
no_get_fd, /* get_fd */
default_map_access, /* map_access */
default_get_sd, /* get_sd */
default_set_sd, /* set_sd */
no_get_full_name, /* get_full_name */
no_lookup_name, /* lookup_name */
no_link_name, /* link_name */
NULL, /* unlink_name */
no_open_file, /* open_file */
no_kernel_obj_list, /* get_kernel_obj_list */
no_close_handle, /* close_handle */
async_destroy /* destroy */
};
static inline void async_reselect( struct async *async )
{
if (async->queue && async->fd) fd_reselect_async( async->fd, async->queue );
}
static void async_dump( struct object *obj, int verbose )
{
struct async *async = (struct async *)obj;
assert( obj->ops == &async_ops );
fprintf( stderr, "Async thread=%p\n", async->thread );
}
2015-05-08 10:32:06 +02:00
static int async_signaled( struct object *obj, struct wait_queue_entry *entry )
{
struct async *async = (struct async *)obj;
assert( obj->ops == &async_ops );
return async->signaled;
}
static void async_satisfied( struct object *obj, struct wait_queue_entry *entry )
{
struct async *async = (struct async *)obj;
assert( obj->ops == &async_ops );
/* we only return an async handle for asyncs created via create_request_async() */
assert( async->iosb );
if (async->direct_result)
{
async_set_result( &async->obj, async->iosb->status, async->iosb->result );
async->direct_result = 0;
}
if (async->initial_status == STATUS_PENDING && async->blocking)
set_wait_status( entry, async->iosb->status );
else
set_wait_status( entry, async->initial_status );
/* close wait handle here to avoid extra server round trip */
if (async->wait_handle)
{
close_handle( async->thread->process, async->wait_handle );
async->wait_handle = 0;
}
}
static void async_destroy( struct object *obj )
{
struct async *async = (struct async *)obj;
assert( obj->ops == &async_ops );
list_remove( &async->process_entry );
if (async->queue)
{
list_remove( &async->queue_entry );
async_reselect( async );
}
else if (async->fd) release_object( async->fd );
if (async->timeout) remove_timeout_user( async->timeout );
if (async->completion) release_object( async->completion );
if (async->event) release_object( async->event );
if (async->iosb) release_object( async->iosb );
release_object( async->thread );
}
/* notifies client thread of new status of its async request */
void async_terminate( struct async *async, unsigned int status )
{
struct iosb *iosb = async->iosb;
if (async->terminated) return;
async->terminated = 1;
if (async->iosb && async->iosb->status == STATUS_PENDING) async->iosb->status = status;
if (status == STATUS_ALERTED)
async->alerted = 1;
/* if no APC could be queued (e.g. the process is terminated),
* thread_queue_apc() may trigger async_set_result(), which may drop the
* last reference to the async, so grab a temporary reference here */
grab_object( async );
if (!async->direct_result)
{
apc_call_t data;
memset( &data, 0, sizeof(data) );
data.type = APC_ASYNC_IO;
data.async_io.user = async->data.user;
data.async_io.result = iosb ? iosb->result : 0;
/* this can happen if the initial status was unknown (i.e. for device
* files). the client should not fill the IOSB in this case; pass it as
* NULL to communicate that.
* note that we check the IOSB status and not the initial status */
if (NT_ERROR( status ) && (!is_fd_overlapped( async->fd ) || !async->pending))
data.async_io.sb = 0;
else
data.async_io.sb = async->data.iosb;
/* if there is output data, the client needs to make an extra request
* to retrieve it; use STATUS_ALERTED to signal this case */
if (iosb && iosb->out_data)
data.async_io.status = STATUS_ALERTED;
else
data.async_io.status = status;
thread_queue_apc( async->thread->process, async->thread, &async->obj, &data );
}
async_reselect( async );
release_object( async );
}
/* callback for timeout on an async request */
static void async_timeout( void *private )
{
struct async *async = private;
async->timeout = NULL;
async_terminate( async, async->timeout_status );
}
/* free an async queue, cancelling all async operations */
void free_async_queue( struct async_queue *queue )
{
struct async *async, *next;
LIST_FOR_EACH_ENTRY_SAFE( async, next, &queue->queue, struct async, queue_entry )
{
if (!async->completion) async->completion = fd_get_completion( async->fd, &async->comp_key );
async->fd = NULL;
async_terminate( async, STATUS_HANDLES_CLOSED );
async->queue = NULL;
release_object( &async->obj );
}
}
void queue_async( struct async_queue *queue, struct async *async )
{
/* fd will be set to NULL in free_async_queue when fd is destroyed */
release_object( async->fd );
async->queue = queue;
grab_object( async );
list_add_tail( &queue->queue, &async->queue_entry );
set_fd_signaled( async->fd, 0 );
}
/* create an async on a given queue of a fd */
struct async *create_async( struct fd *fd, struct thread *thread, const async_data_t *data, struct iosb *iosb )
{
struct event *event = NULL;
struct async *async;
if (data->event && !(event = get_event_obj( thread->process, data->event, EVENT_MODIFY_STATE )))
return NULL;
if (!(async = alloc_object( &async_ops )))
{
if (event) release_object( event );
return NULL;
}
async->thread = (struct thread *)grab_object( thread );
async->event = event;
async->data = *data;
async->timeout = NULL;
async->queue = NULL;
async->fd = (struct fd *)grab_object( fd );
async->initial_status = STATUS_PENDING;
async->signaled = 0;
async->pending = 1;
async->wait_handle = 0;
async->direct_result = 0;
async->alerted = 0;
async->terminated = 0;
async->canceled = 0;
async->unknown_status = 0;
async->blocking = !is_fd_overlapped( fd );
async->completion = fd_get_completion( fd, &async->comp_key );
async->comp_flags = 0;
async->completion_callback = NULL;
async->completion_callback_private = NULL;
if (iosb) async->iosb = (struct iosb *)grab_object( iosb );
else async->iosb = NULL;
list_add_head( &thread->process->asyncs, &async->process_entry );
if (event) reset_event( event );
if (async->completion && data->apc)
{
release_object( async );
set_error( STATUS_INVALID_PARAMETER );
return NULL;
}
return async;
}
/* set the initial status of an async whose status was previously unknown
* the initial status may be STATUS_PENDING */
void async_set_initial_status( struct async *async, unsigned int status )
{
server: Actually set initial status in set_async_direct_result handler. Commit 15483b1a126 (server: Allow calling async_handoff() with status code STATUS_ALERTED., 2022-02-10) introduced the set_async_direct_result handler which calls async_set_initial_status(). However, the async_set_initial_status() call does nothing since async->terminated is set, leaving the async in a confusing state (unknown_status = 1 but pending/completed). So far, this issue is unlikely to have been a problem in practice for the following reasons: 1. async_set_initial_status() would have unset unknown_status, but it remains set instead. This is usually not a problem, since unknown_status is usually ever read by code paths effectively unreachable for non-device (e.g. socket) asyncs. It would still potentially allow set_async_direct_result to be called multiple times, but it wouldn't actually happen in practice unless something goes wrong. 2. async_set_initial_status() would have set initial_status; however, it is left with the default value STATUS_PENDING. If the actual status is something other than that, the handler closes the wait handle and async_satisfied (the only real consumer of initial_status) would never be called anyway. For reasons above, this issue is not effectively observable or testable. Nonetheless, the current code does leave the async object in an inconsistent state. Fix this by removing the !async->terminated check in async_set_initial_status(). Also, remove assert( async->unknown_status ). The client can now trigger the assert() by calling set_async_direct_result on a device async, thereby causing async_set_initial_status() to be called twice. Signed-off-by: Jinoh Kang <jinoh.kang.kr@gmail.com> Signed-off-by: Zebediah Figura <zfigura@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>
2022-03-19 23:28:01 +01:00
async->initial_status = status;
async->unknown_status = 0;
}
void set_async_pending( struct async *async )
{
if (!async->terminated)
async->pending = 1;
}
void async_wake_obj( struct async *async )
{
assert( !async->unknown_status );
if (!async->blocking)
{
async->signaled = 1;
wake_up( &async->obj, 0 );
}
}
static void async_call_completion_callback( struct async *async )
{
if (async->completion_callback)
async->completion_callback( async->completion_callback_private );
async->completion_callback = NULL;
}
/* return async object status and wait handle to client */
obj_handle_t async_handoff( struct async *async, data_size_t *result, int force_blocking )
{
async->blocking = force_blocking || async->blocking;
if (async->unknown_status)
{
/* even the initial status is not known yet */
set_error( STATUS_PENDING );
return async->wait_handle;
}
if (get_error() == STATUS_ALERTED)
{
/* give the client opportunity to complete synchronously. after the
* client performs the I/O, it reports the result back to the server
* via the set_async_direct_result request. if it turns out that the
* I/O request is not actually immediately satiable, the client may
* then choose to re-queue the async by reporting STATUS_PENDING
* instead.
*
* since we're deferring the initial I/O (to the client), we mark the
* async as having unknown initial status (unknown_status = 1). note
* that we don't reuse async_set_unknown_status() here. this is because
* the one responsible for performing the I/O is not the device driver,
* but instead the client that requested the I/O in the first place.
*
* also, async_set_unknown_status() would set direct_result to zero
* forcing APC_ASYNC_IO to fire in async_terminate(), which is not
* useful due to subtle semantic differences between synchronous and
* asynchronous completion.
*/
async->unknown_status = 1;
async_terminate( async, STATUS_ALERTED );
return async->wait_handle;
}
async->initial_status = get_error();
if (!async->pending && NT_ERROR( get_error() ))
{
async->iosb->status = get_error();
async_call_completion_callback( async );
close_handle( async->thread->process, async->wait_handle );
async->wait_handle = 0;
return 0;
}
if (get_error() != STATUS_PENDING)
{
/* status and data are already set and returned */
async_terminate( async, get_error() );
}
else if (async->iosb->status != STATUS_PENDING)
{
/* result is already available in iosb, return it */
if (async->iosb->out_data)
{
set_reply_data_ptr( async->iosb->out_data, async->iosb->out_size );
async->iosb->out_data = NULL;
}
}
if (async->iosb->status != STATUS_PENDING)
{
if (result) *result = async->iosb->result;
async->signaled = 1;
}
else
{
async->direct_result = 0;
async->pending = 1;
if (!async->blocking)
{
close_handle( async->thread->process, async->wait_handle);
async->wait_handle = 0;
}
}
async->initial_status = async->iosb->status;
set_error( async->iosb->status );
return async->wait_handle;
}
/* complete a request-based async with a pre-allocated buffer */
void async_request_complete( struct async *async, unsigned int status, data_size_t result,
data_size_t out_size, void *out_data )
{
struct iosb *iosb = async_get_iosb( async );
/* the async may have already been canceled */
if (iosb->status != STATUS_PENDING)
{
release_object( iosb );
free( out_data );
return;
}
iosb->status = status;
iosb->result = result;
iosb->out_data = out_data;
iosb->out_size = out_size;
release_object( iosb );
async_terminate( async, status );
}
/* complete a request-based async */
void async_request_complete_alloc( struct async *async, unsigned int status, data_size_t result,
data_size_t out_size, const void *out_data )
{
void *out_data_copy = NULL;
if (out_size && !(out_data_copy = memdup( out_data, out_size )))
{
async_terminate( async, STATUS_NO_MEMORY );
return;
}
async_request_complete( async, status, result, out_size, out_data_copy );
}
/* mark an async as having unknown initial status */
void async_set_unknown_status( struct async *async )
{
async->unknown_status = 1;
async->direct_result = 0;
}
/* set the timeout of an async operation */
void async_set_timeout( struct async *async, timeout_t timeout, unsigned int status )
{
if (async->timeout) remove_timeout_user( async->timeout );
if (timeout != TIMEOUT_INFINITE) async->timeout = add_timeout_user( timeout, async_timeout, async );
else async->timeout = NULL;
async->timeout_status = status;
}
/* set a callback to be notified when the async is completed */
void async_set_completion_callback( struct async *async, async_completion_callback func, void *private )
{
async->completion_callback = func;
async->completion_callback_private = private;
}
static void add_async_completion( struct async *async, apc_param_t cvalue, unsigned int status,
apc_param_t information )
{
if (async->fd && !async->completion) async->completion = fd_get_completion( async->fd, &async->comp_key );
if (async->completion) add_completion( async->completion, async->comp_key, cvalue, status, information );
}
/* store the result of the client-side async callback */
void async_set_result( struct object *obj, unsigned int status, apc_param_t total )
{
struct async *async = (struct async *)obj;
if (obj->ops != &async_ops) return; /* in case the client messed up the APC results */
assert( async->terminated ); /* it must have been woken up if we get a result */
if (async->unknown_status) async_set_initial_status( async, status );
if (async->alerted && status == STATUS_PENDING) /* restart it */
{
async->terminated = 0;
async->alerted = 0;
async_reselect( async );
}
else
{
if (async->timeout) remove_timeout_user( async->timeout );
async->timeout = NULL;
async->terminated = 1;
if (async->iosb) async->iosb->status = status;
/* don't signal completion if the async failed synchronously
* this can happen if the initial status was unknown (i.e. for device files)
* note that we check the IOSB status here, not the initial status */
if (async->pending || !NT_ERROR( status ))
{
if (async->data.apc)
{
apc_call_t data;
memset( &data, 0, sizeof(data) );
data.type = APC_USER;
data.user.func = async->data.apc;
data.user.args[0] = async->data.apc_context;
data.user.args[1] = async->data.iosb;
data.user.args[2] = 0;
thread_queue_apc( NULL, async->thread, NULL, &data );
}
else if (async->data.apc_context && (async->pending ||
!(async->comp_flags & FILE_SKIP_COMPLETION_PORT_ON_SUCCESS)))
{
add_async_completion( async, async->data.apc_context, status, total );
}
if (async->event) set_event( async->event );
else if (async->fd) set_fd_signaled( async->fd, 1 );
}
if (!async->signaled)
{
async->signaled = 1;
wake_up( &async->obj, 0 );
}
async_call_completion_callback( async );
if (async->queue)
{
list_remove( &async->queue_entry );
async_reselect( async );
async->fd = NULL;
async->queue = NULL;
release_object( async );
}
}
}
/* check if an async operation is waiting to be alerted */
int async_waiting( struct async_queue *queue )
{
struct list *ptr;
struct async *async;
if (!(ptr = list_head( &queue->queue ))) return 0;
async = LIST_ENTRY( ptr, struct async, queue_entry );
return !async->terminated;
}
static int cancel_async( struct process *process, struct object *obj, struct thread *thread, client_ptr_t iosb )
{
struct async *async;
int woken = 0;
/* FIXME: it would probably be nice to replace the "canceled" flag with a
* single LIST_FOR_EACH_ENTRY_SAFE, but currently cancelling an async can
* cause other asyncs to be removed via async_reselect() */
restart:
LIST_FOR_EACH_ENTRY( async, &process->asyncs, struct async, process_entry )
{
if (async->terminated || async->canceled) continue;
if ((!obj || (get_fd_user( async->fd ) == obj)) &&
(!thread || async->thread == thread) &&
(!iosb || async->data.iosb == iosb))
{
async->canceled = 1;
fd_cancel_async( async->fd, async );
woken++;
goto restart;
}
}
return woken;
}
void cancel_process_asyncs( struct process *process )
{
cancel_async( process, NULL, NULL, 0 );
}
/* wake up async operations on the queue */
void async_wake_up( struct async_queue *queue, unsigned int status )
{
struct list *ptr, *next;
LIST_FOR_EACH_SAFE( ptr, next, &queue->queue )
{
struct async *async = LIST_ENTRY( ptr, struct async, queue_entry );
async_terminate( async, status );
if (status == STATUS_ALERTED) break; /* only wake up the first one */
}
}
static void iosb_dump( struct object *obj, int verbose );
static void iosb_destroy( struct object *obj );
static const struct object_ops iosb_ops =
{
sizeof(struct iosb), /* size */
&no_type, /* type */
iosb_dump, /* dump */
no_add_queue, /* add_queue */
NULL, /* remove_queue */
NULL, /* signaled */
NULL, /* satisfied */
no_signal, /* signal */
no_get_fd, /* get_fd */
default_map_access, /* map_access */
default_get_sd, /* get_sd */
default_set_sd, /* set_sd */
no_get_full_name, /* get_full_name */
no_lookup_name, /* lookup_name */
no_link_name, /* link_name */
NULL, /* unlink_name */
no_open_file, /* open_file */
no_kernel_obj_list, /* get_kernel_obj_list */
no_close_handle, /* close_handle */
iosb_destroy /* destroy */
};
static void iosb_dump( struct object *obj, int verbose )
{
assert( obj->ops == &iosb_ops );
fprintf( stderr, "I/O status block\n" );
}
static void iosb_destroy( struct object *obj )
{
struct iosb *iosb = (struct iosb *)obj;
free( iosb->in_data );
free( iosb->out_data );
}
/* allocate iosb struct */
static struct iosb *create_iosb( const void *in_data, data_size_t in_size, data_size_t out_size )
{
struct iosb *iosb;
if (!(iosb = alloc_object( &iosb_ops ))) return NULL;
iosb->status = STATUS_PENDING;
iosb->result = 0;
iosb->in_size = in_size;
iosb->in_data = NULL;
iosb->out_size = out_size;
iosb->out_data = NULL;
if (in_size && !(iosb->in_data = memdup( in_data, in_size )))
{
release_object( iosb );
iosb = NULL;
}
return iosb;
}
/* create an async associated with iosb for async-based requests
* returned async must be passed to async_handoff */
struct async *create_request_async( struct fd *fd, unsigned int comp_flags, const async_data_t *data )
{
struct async *async;
struct iosb *iosb;
if (!(iosb = create_iosb( get_req_data(), get_req_data_size(), get_reply_max_size() )))
return NULL;
async = create_async( fd, current, data, iosb );
release_object( iosb );
if (async)
{
if (!(async->wait_handle = alloc_handle( current->process, async, SYNCHRONIZE, 0 )))
{
release_object( async );
return NULL;
}
async->pending = 0;
async->direct_result = 1;
async->comp_flags = comp_flags;
}
return async;
}
struct iosb *async_get_iosb( struct async *async )
{
return async->iosb ? (struct iosb *)grab_object( async->iosb ) : NULL;
}
struct thread *async_get_thread( struct async *async )
{
return async->thread;
}
/* find the first pending async in queue */
struct async *find_pending_async( struct async_queue *queue )
{
struct async *async;
LIST_FOR_EACH_ENTRY( async, &queue->queue, struct async, queue_entry )
if (!async->terminated) return (struct async *)grab_object( async );
return NULL;
}
/* cancels all async I/O */
DECL_HANDLER(cancel_async)
{
struct object *obj = get_handle_obj( current->process, req->handle, 0, NULL );
struct thread *thread = req->only_thread ? current : NULL;
if (obj)
{
int count = cancel_async( current->process, obj, thread, req->iosb );
if (!count && req->iosb) set_error( STATUS_NOT_FOUND );
release_object( obj );
}
}
/* get async result from associated iosb */
DECL_HANDLER(get_async_result)
{
struct iosb *iosb = NULL;
struct async *async;
LIST_FOR_EACH_ENTRY( async, &current->process->asyncs, struct async, process_entry )
if (async->data.user == req->user_arg)
{
iosb = async->iosb;
break;
}
if (!iosb)
{
set_error( STATUS_INVALID_PARAMETER );
return;
}
if (iosb->out_data)
{
data_size_t size = min( iosb->out_size, get_reply_max_size() );
if (size)
{
set_reply_data_ptr( iosb->out_data, size );
iosb->out_data = NULL;
}
}
set_error( iosb->status );
}
/* notify direct completion of async and close the wait handle if not blocking */
DECL_HANDLER(set_async_direct_result)
{
struct async *async = (struct async *)get_handle_obj( current->process, req->handle, 0, &async_ops );
unsigned int status = req->status;
if (!async) return;
if (!async->unknown_status || !async->terminated || !async->alerted)
{
set_error( STATUS_INVALID_PARAMETER );
release_object( &async->obj );
return;
}
if (status == STATUS_PENDING)
{
async->direct_result = 0;
async->pending = 1;
}
else if (req->mark_pending)
{
async->pending = 1;
}
/* if the I/O has completed successfully (or unsuccessfully, and
* async->pending is set), the client would have already set the IOSB.
* therefore, we can do async_set_result() directly and let the client skip
* waiting on wait_handle.
*/
async_set_result( &async->obj, status, req->information );
/* close wait handle here to avoid extra server round trip, if the I/O
* either has completed, or is pending and not blocking.
*/
if (status != STATUS_PENDING || !async->blocking)
{
close_handle( async->thread->process, async->wait_handle );
async->wait_handle = 0;
}
/* report back to the client whether the wait handle has been closed.
* handle will be 0 if closed by us; otherwise the original value is
* retained
*/
reply->handle = async->wait_handle;
release_object( &async->obj );
}