source: rtems/cpukit/score/src/coremsg.c @ b1b6f3b0

5
Last change on this file since b1b6f3b0 was b1b6f3b0, checked in by Sebastian Huber <sebastian.huber@…>, on 05/03/16 at 10:57:16

confdefs.h: Fix message queue size estimate

Account for maximum message size alignment. Simplify
_CORE_message_queue_Initialize().

  • Property mode set to 100644
File size: 3.1 KB
Line 
1/**
2 *  @file
3 *
4 *  @brief Initialize a Message Queue
5 *  @ingroup ScoreMessageQueue
6 */
7
8/*
9 *  COPYRIGHT (c) 1989-2009.
10 *  On-Line Applications Research Corporation (OAR).
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.rtems.org/license/LICENSE.
15 */
16
17#if HAVE_CONFIG_H
18#include "config.h"
19#endif
20
21#include <rtems/score/coremsgimpl.h>
22#include <rtems/score/wkspace.h>
23
24/*
25 *  size_t_mult32_with_overflow
26 *
27 *  This method multiplies two size_t 32-bit numbers and checks
28 *  for overflow.  It returns false if an overflow occurred and
29 *  the result is bad.
30 */
31static inline bool size_t_mult32_with_overflow(
32  size_t  a,
33  size_t  b,
34  size_t *c
35)
36{
37  long long x = (long long)a*b;
38
39  if ( x > SIZE_MAX )
40    return false;
41  *c = (size_t) x;
42  return true;
43}
44
45bool _CORE_message_queue_Initialize(
46  CORE_message_queue_Control     *the_message_queue,
47  CORE_message_queue_Disciplines  discipline,
48  uint32_t                        maximum_pending_messages,
49  size_t                          maximum_message_size
50)
51{
52  size_t message_buffering_required = 0;
53  size_t aligned_message_size;
54  size_t align_mask;
55
56  the_message_queue->maximum_pending_messages   = maximum_pending_messages;
57  the_message_queue->number_of_pending_messages = 0;
58  the_message_queue->maximum_message_size       = maximum_message_size;
59  _CORE_message_queue_Set_notify( the_message_queue, NULL );
60
61  /*
62   * Align up the maximum message size to be an integral multiple of the
63   * pointer size.
64   */
65  align_mask = sizeof(uintptr_t) - 1;
66  aligned_message_size = ( maximum_message_size + align_mask ) & ~align_mask;
67
68  /*
69   * Check for an integer overflow.  It can occur while aligning up the maximum
70   * message size.
71   */
72  if (aligned_message_size < maximum_message_size)
73    return false;
74
75  /*
76   *  Calculate how much total memory is required for message buffering and
77   *  check for overflow on the multiplication.
78   */
79  if ( !size_t_mult32_with_overflow(
80        (size_t) maximum_pending_messages,
81        aligned_message_size + sizeof(CORE_message_queue_Buffer_control),
82        &message_buffering_required ) )
83    return false;
84
85  /*
86   *  Attempt to allocate the message memory
87   */
88  the_message_queue->message_buffers = (CORE_message_queue_Buffer *)
89     _Workspace_Allocate( message_buffering_required );
90
91  if (the_message_queue->message_buffers == 0)
92    return false;
93
94  /*
95   *  Initialize the pool of inactive messages, pending messages,
96   *  and set of waiting threads.
97   */
98  _Chain_Initialize (
99    &the_message_queue->Inactive_messages,
100    the_message_queue->message_buffers,
101    (size_t) maximum_pending_messages,
102    aligned_message_size + sizeof( CORE_message_queue_Buffer_control )
103  );
104
105  _Chain_Initialize_empty( &the_message_queue->Pending_messages );
106
107  _Thread_queue_Initialize( &the_message_queue->Wait_queue );
108
109  if ( discipline == CORE_MESSAGE_QUEUE_DISCIPLINES_PRIORITY ) {
110    the_message_queue->operations = &_Thread_queue_Operations_priority;
111  } else {
112    the_message_queue->operations = &_Thread_queue_Operations_FIFO;
113  }
114
115  return true;
116}
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