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/*
* CORE Message Queue Handler
*
* DESCRIPTION:
*
* This package is the implementation of the CORE Message Queue Handler.
* This core object provides task synchronization and communication functions
* via messages passed to queue objects.
*
* COPYRIGHT (c) 1989-2009.
* On-Line Applications Research Corporation (OAR).
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/system.h>
#include <rtems/score/chain.h>
#include <rtems/score/isr.h>
#include <rtems/score/object.h>
#include <rtems/score/coremsg.h>
#include <rtems/score/states.h>
#include <rtems/score/thread.h>
#include <rtems/score/wkspace.h>
/*
* size_t_mult32_with_overflow
*
* This method multiplies two size_t 32-bit numbers and checks
* for overflow. It returns false if an overflow occurred and
* the result is bad.
*/
static inline bool size_t_mult32_with_overflow(
size_t a,
size_t b,
size_t *c
)
{
long long x = (long long)a*b;
if ( x > SIZE_MAX )
return false;
*c = (size_t) x;
return true;
}
/*
* _CORE_message_queue_Initialize
*
* This routine initializes a newly created message queue based on the
* specified data.
*
* Input parameters:
* the_message_queue - the message queue to initialize
* the_class - the API specific object class
* the_message_queue_attributes - the message queue's attributes
* maximum_pending_messages - maximum message and reserved buffer count
* maximum_message_size - maximum size of each message
*
* Output parameters:
* true - if the message queue is initialized
* false - if the message queue is NOT initialized
*/
bool _CORE_message_queue_Initialize(
CORE_message_queue_Control *the_message_queue,
CORE_message_queue_Attributes *the_message_queue_attributes,
uint32_t maximum_pending_messages,
size_t maximum_message_size
)
{
size_t message_buffering_required = 0;
size_t allocated_message_size;
the_message_queue->maximum_pending_messages = maximum_pending_messages;
the_message_queue->number_of_pending_messages = 0;
the_message_queue->maximum_message_size = maximum_message_size;
_CORE_message_queue_Set_notify( the_message_queue, NULL, NULL );
/*
* Round size up to multiple of a pointer for chain init and
* check for overflow on adding overhead to each message.
*/
allocated_message_size = maximum_message_size;
if (allocated_message_size & (sizeof(uint32_t) - 1)) {
allocated_message_size += sizeof(uint32_t);
allocated_message_size &= ~(sizeof(uint32_t) - 1);
}
if (allocated_message_size < maximum_message_size)
return false;
/*
* Calculate how much total memory is required for message buffering and
* check for overflow on the multiplication.
*/
if ( !size_t_mult32_with_overflow(
(size_t) maximum_pending_messages,
allocated_message_size + sizeof(CORE_message_queue_Buffer_control),
&message_buffering_required ) )
return false;
/*
* Attempt to allocate the message memory
*/
the_message_queue->message_buffers = (CORE_message_queue_Buffer *)
_Workspace_Allocate( message_buffering_required );
if (the_message_queue->message_buffers == 0)
return false;
/*
* Initialize the pool of inactive messages, pending messages,
* and set of waiting threads.
*/
_Chain_Initialize (
&the_message_queue->Inactive_messages,
the_message_queue->message_buffers,
(size_t) maximum_pending_messages,
allocated_message_size + sizeof( CORE_message_queue_Buffer_control )
);
_Chain_Initialize_empty( &the_message_queue->Pending_messages );
_Thread_queue_Initialize(
&the_message_queue->Wait_queue,
_CORE_message_queue_Is_priority( the_message_queue_attributes ) ?
THREAD_QUEUE_DISCIPLINE_PRIORITY : THREAD_QUEUE_DISCIPLINE_FIFO,
STATES_WAITING_FOR_MESSAGE,
CORE_MESSAGE_QUEUE_STATUS_TIMEOUT
);
return true;
}
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