1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
// -*- C++ -*-
//=============================================================================
/**
* @file Shared_Memory_Pool.h
*
* $Id$
*
* @author Dougls C. Schmidt <schmidt@cs.wustl.edu>
* @author Prashant Jain <pjain@cs.wustl.edu>
*/
//=============================================================================
#ifndef ACE_SHARED_MEMORY_POOL_H
#define ACE_SHARED_MEMORY_POOL_H
#include /**/ "ace/pre.h"
#include /**/ "ace/ACE_export.h"
#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */
#if !defined (ACE_LACKS_SYSV_SHMEM)
#include "ace/ACE.h"
#include "ace/Event_Handler.h"
#include "ace/Sig_Handler.h"
#include "ace/os_include/sys/os_mman.h"
ACE_BEGIN_VERSIONED_NAMESPACE_DECL
/**
* @class ACE_Shared_Memory_Pool_Options
*
* @brief Helper class for Shared Memory Pool constructor options.
*
* This should be a nested class, but that breaks too many
* compilers.
*/
class ACE_Export ACE_Shared_Memory_Pool_Options
{
public:
/// Initialization method.
ACE_Shared_Memory_Pool_Options (
const char *base_addr = ACE_DEFAULT_BASE_ADDR,
size_t max_segments = ACE_DEFAULT_MAX_SEGMENTS,
size_t file_perms = ACE_DEFAULT_FILE_PERMS,
ACE_OFF_T minimum_bytes = 0,
size_t segment_size = ACE_DEFAULT_SEGMENT_SIZE);
/// Base address of the memory-mapped backing store.
const char *base_addr_;
/// Number of shared memory segments to allocate.
size_t max_segments_;
/// What the minimum bytes of the initial segment should be.
ACE_OFF_T minimum_bytes_;
/// File permissions to use when creating/opening a segment.
size_t file_perms_;
/// Shared memory segment size.
size_t segment_size_;
};
/**
* @class ACE_Shared_Memory_Pool
*
* @brief Make a memory pool that is based on System V shared memory
* (shmget(2) etc.). This implementation allows memory to be
* shared between processes. If your platform doesn't support
* System V shared memory (e.g., Win32 and many RTOS platforms
* do not) then you should use ACE_MMAP_Memory_Pool instead of this
* class. In fact, you should probably use ACE_MMAP_Memory_Pool on
* platforms that *do* support System V shared memory since it
* provides more powerful features, such as persistent backing store
* and greatly scalability.
*/
class ACE_Export ACE_Shared_Memory_Pool : public ACE_Event_Handler
{
public:
typedef ACE_Shared_Memory_Pool_Options OPTIONS;
/// Initialize the pool.
ACE_Shared_Memory_Pool (const ACE_TCHAR *backing_store_name = 0,
const OPTIONS *options = 0);
virtual ~ACE_Shared_Memory_Pool (void);
/// Ask system for initial chunk of local memory.
virtual void *init_acquire (size_t nbytes,
size_t &rounded_bytes,
int &first_time);
/**
* Acquire at least @a nbytes from the memory pool. @a rounded_byes is
* the actual number of bytes allocated. Also acquires an internal
* semaphore that ensures proper serialization of Memory_Pool
* initialization across processes.
*/
virtual void *acquire (size_t nbytes,
size_t &rounded_bytes);
/// Instruct the memory pool to release all of its resources.
virtual int release (int destroy = 1);
/// Sync the memory region to the backing store starting at
/// @c this->base_addr_.
virtual int sync (ssize_t len = -1, int flags = MS_SYNC);
/// Sync the memory region to the backing store starting at @a addr.
virtual int sync (void *addr, size_t len, int flags = MS_SYNC);
/**
* Change the protection of the pages of the mapped region to @a prot
* starting at @c this->base_addr_ up to @a len bytes. If @a len == -1
* then change protection of all pages in the mapped region.
*/
virtual int protect (ssize_t len = -1, int prot = PROT_RDWR);
/// Change the protection of the pages of the mapped region to @a prot
/// starting at @a addr up to @a len bytes.
virtual int protect (void *addr, size_t len, int prot = PROT_RDWR);
/// Return the base address of this memory pool, 0 if base_addr
/// never changes.
virtual void *base_addr (void) const;
/// Dump the state of an object.
virtual void dump (void) const;
/// Declare the dynamic allocation hooks.
ACE_ALLOC_HOOK_DECLARE;
protected:
/// Implement the algorithm for rounding up the request to an
/// appropriate chunksize.
virtual size_t round_up (size_t nbytes);
/**
* Commits a new shared memory segment if necessary after an
* <acquire> or a signal. @a offset is set to the new offset into
* the backing store.
*/
virtual int commit_backing_store_name (size_t rounded_bytes,
ACE_OFF_T &offset);
/// Keeps track of all the segments being used.
struct SHM_TABLE
{
/// Shared memory segment key.
key_t key_;
/// Shared memory segment internal id.
int shmid_;
/// Is the segment currently used.;
int used_;
};
/**
* Base address of the shared memory segment. If this has the value
* of 0 then the OS is free to select any address, otherwise this
* value is what the OS must try to use to map the shared memory
* segment.
*/
void *base_addr_;
/// File permissions to use when creating/opening a segment.
size_t file_perms_;
/// Number of shared memory segments in the <SHM_TABLE> table.
size_t max_segments_;
/// What the minimim bytes of the initial segment should be.
ACE_OFF_T minimum_bytes_;
/// Shared memory segment size.
size_t segment_size_;
/// Base shared memory key for the segment.
key_t base_shm_key_;
/// Find the segment that contains the @a searchPtr
virtual int find_seg (const void *const searchPtr,
ACE_OFF_T &offset,
size_t &counter);
/// Determine how much memory is currently in use.
virtual int in_use (ACE_OFF_T &offset,
size_t &counter);
/// Handles SIGSEGV.
ACE_Sig_Handler signal_handler_;
/// Handle SIGSEGV and SIGBUS signals to remap shared memory
/// properly.
virtual int handle_signal (int signum, siginfo_t *, ucontext_t *);
};
ACE_END_VERSIONED_NAMESPACE_DECL
#endif /* !ACE_LACKS_SYSV_SHMEM */
#include /**/ "ace/post.h"
#endif /* ACE_SHARED_MEMORY_POOL_H */
|
