Fawkes API  Fawkes Development Version
shm.h
1 
2 /***************************************************************************
3  * shm.h - shared memory segment
4  *
5  * Created: Thu Jan 12 13:12:24 2006
6  * Copyright 2005-2011 Tim Niemueller [www.niemueller.de]
7  *
8  ****************************************************************************/
9 
10 /* This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation; either version 2 of the License, or
13  * (at your option) any later version. A runtime exception applies to
14  * this software (see LICENSE.GPL_WRE file mentioned below for details).
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Library General Public License for more details.
20  *
21  * Read the full text in the LICENSE.GPL_WRE file in the doc directory.
22  */
23 
24 #ifndef __UTILS_IPC_SHM_H_
25 #define __UTILS_IPC_SHM_H_
26 
27 // for size_t
28 #include <sys/types.h>
29 #include <utils/ipc/shm_registry.h>
30 
31 namespace fawkes {
32 
34  public:
35  virtual ~SharedMemoryHeader() {}
36  virtual bool matches(void *memptr) = 0;
37  virtual size_t size() = 0;
38  virtual void initialize(void *memptr) = 0;
39  virtual void set(void *memptr) = 0;
40  virtual void reset() = 0;
41  virtual size_t data_size() = 0;
42  virtual SharedMemoryHeader * clone() const = 0;
43  virtual bool operator==(const SharedMemoryHeader &s) const = 0;
44 };
45 
46 class SharedMemoryLister;
47 class SemaphoreSet;
48 
50 {
51 
52  public:
53 
54  static const unsigned int MagicTokenSize;
55  static const short MaxNumConcurrentReaders;
56 
57  SharedMemory(const char *magic_token,
58  SharedMemoryHeader *header,
59  bool is_read_only, bool create,
60  bool destroy_on_delete,
61  const char *registry_name = 0);
62 
63  SharedMemory(const SharedMemory &s);
64 
65  virtual ~SharedMemory();
66 
67  bool is_read_only() const;
68  bool is_destroyed() const;
69  bool is_swapable() const;
70  bool is_valid() const;
71  bool is_creator() const;
72  bool is_protected() const;
73  void * memptr() const;
74  size_t data_size() const;
75  int shmem_id() const;
76  unsigned int num_attached() const;
77 
78  void set(void *memptr);
79  void set_destroy_on_delete(bool destroy);
80  void add_semaphore();
81  void set_swapable(bool swapable);
82 
83  void lock_for_read();
84  bool try_lock_for_read();
85  void lock_for_write();
86  bool try_lock_for_write();
87  void unlock();
88 
89  void * ptr(void *addr) const;
90  void * addr(void *ptr) const;
91 
92  static void list(const char *magic_token,
93  SharedMemoryHeader *header, SharedMemoryLister *lister,
94  const char *registry_name = 0);
95 
96  static void erase(const char *magic_token,
97  SharedMemoryHeader *header,
98  SharedMemoryLister *lister = 0,
99  const char *registry_name = 0);
100 
101  static void erase_orphaned(const char *magic_token,
102  SharedMemoryHeader *header,
103  SharedMemoryLister *lister = 0,
104  const char *registry_name = 0);
105 
106  static bool exists(const char *magic_token,
107  SharedMemoryHeader *header,
108  const char *registry_name = 0);
109 
110  static bool is_destroyed(int shm_id);
111  static bool is_swapable(int shm_id);
112  static unsigned int num_attached(int shm_id);
113 
115  {
116  public:
119  SharedMemoryIterator(std::list<SharedMemoryRegistry::SharedMemID> ids,
120  SharedMemoryHeader *header);
122 
123  SharedMemoryIterator & operator++ (); // prefix
124  SharedMemoryIterator operator++ (int inc); // postfix
125  SharedMemoryIterator & operator+ (unsigned int i);
126  SharedMemoryIterator & operator+= (unsigned int i);
127  bool operator== (const SharedMemoryIterator & s) const;
128  bool operator!= (const SharedMemoryIterator & s) const;
129  const SharedMemoryHeader * operator* () const;
130  SharedMemoryIterator & operator= (const SharedMemoryIterator & shmit);
131 
132  const char * magic_token() const;
133  int shmid() const;
134  int semaphore() const;
135  size_t segmsize() const;
136  size_t segmnattch() const;
137  void * databuf() const;
138 
139  private:
140  void attach();
141  void reset();
142 
143  bool __initialized;
144  std::list<SharedMemoryRegistry::SharedMemID> __ids;
145  std::list<SharedMemoryRegistry::SharedMemID>::iterator __id_it;
146  int __cur_shmid;
147  SharedMemoryHeader *__header;
148  void *__shm_buf;
149  void *__data_buf;
150  int __semaphore;
151  size_t __segmsize;
152  size_t __segmnattch;
153  };
154 
155  static SharedMemoryIterator find(const char *magic_token,
156  SharedMemoryHeader *header,
157  const char *registry_name = 0);
158  static SharedMemoryIterator end();
159 
160  protected:
161 
162  /** General header.
163  * This header is stored right after the magic token.
164  */
165  typedef struct {
166  void *shm_addr; /**< Desired shared memory address */
167  int semaphore; /**< Semaphore set ID */
169 
170  SharedMemory(const char *magic_token,
171  bool is_read_only, bool create, bool destroy_on_delete,
172  const char *registry_name = 0);
173 
174  void attach();
175  void free();
176 
177  void *_memptr;
178  size_t _mem_size;
179  size_t _data_size;
188  long unsigned int _shm_offset;
189 
190 
191  private:
192  SharedMemoryRegistry *__shm_registry;
193  char * __registry_name;
194 
195  void *__shared_mem;
196  int __shared_mem_id;
197  void *__shared_mem_upper_bound;
198 
199  bool __created;
200  SemaphoreSet *__semset;
201 
202  bool __lock_aquired;
203  bool __write_lock_aquired;
204 
205 };
206 
207 
208 } // end namespace fawkes
209 
210 #endif
IPC semaphore set.
Definition: semset.h:32
virtual size_t data_size()=0
Return the size of the data.
Fawkes library namespace.
size_t _mem_size
Total size of the segment, including headers.
Definition: shm.h:178
bool _should_create
Create shared memory segment.
Definition: shm.h:183
Shared Memory iterator.
Definition: shm.h:114
size_t _data_size
Size of the data segment only.
Definition: shm.h:179
SharedMemory_header_t * _shm_header
general header as stored in the shared memory segment
Definition: shm.h:186
virtual ~SharedMemoryHeader()
Virtual destructor.
Definition: shm.h:35
Shared memory registry.
Definition: shm_registry.h:40
virtual bool matches(void *memptr)=0
Method to check if the given memptr matches this header.
void * _shm_upper_bound
Upper bound of memory.
Definition: shm.h:187
int semaphore
Semaphore set ID.
Definition: shm.h:167
char * _magic_token
Magic token.
Definition: shm.h:184
char * _shm_magic_token
Magic token as stored in the shared memory segment.
Definition: shm.h:185
virtual bool operator==(const SharedMemoryHeader &s) const =0
Check for equality of headers.
bool _destroy_on_delete
destroy on delete.
Definition: shm.h:182
virtual void initialize(void *memptr)=0
Initialize the header.
void * shm_addr
Desired shared memory address.
Definition: shm.h:166
virtual SharedMemoryHeader * clone() const =0
Clone this shared memory header.
void * _memptr
Pointer to the data segment.
Definition: shm.h:177
Format list output for shared memory segments.
Definition: shm_lister.h:38
Shared memory segment.
Definition: shm.h:49
static const short MaxNumConcurrentReaders
Maximum number of concurrent readers.
Definition: shm.h:55
bool _is_read_only
Read-only.
Definition: shm.h:181
virtual size_t size()=0
Size of the header.
virtual void reset()=0
Reset information previously set with set().
SharedMemoryHeader * _header
Data-specific header.
Definition: shm.h:180
static const unsigned int MagicTokenSize
The magic token size.
Definition: shm.h:54
long unsigned int _shm_offset
Offset to the master&#39;s base addr.
Definition: shm.h:188
Interface for shared memory header.
Definition: shm.h:33