1 |
{Used by IBIPC and implements System V IPC} |
2 |
|
3 |
uses IBMessages, ipc, Errors, baseunix; |
4 |
|
5 |
const |
6 |
IPCFileName: string = 'FB.SQL.MONITOR1_0'; |
7 |
cNumberOfSemaphores = 10; |
8 |
cMutexSemaphore = 0; |
9 |
cMonitorCounter = 1; |
10 |
cReadReadyEventSemaphore = 2; |
11 |
cReadFinishedEventSemaphore = 4; |
12 |
cDataAvailableEventSemaphore = 6; |
13 |
cWriterBusyEventSemaphore = 8; |
14 |
cDefaultTimeout = 10; {seconds } |
15 |
|
16 |
{$IF FPC_FULLVERSION = 30000 } |
17 |
{Fix regression in FPC 3.0.0 ipc.pp unit. Expected to be fixed in fpc 3.0.2} |
18 |
{$IF defined(darwin) } |
19 |
SEM_GETNCNT = 3; { Return the value of sempid (READ) } |
20 |
SEM_GETPID = 4; { Return the value of semval (READ) } |
21 |
SEM_GETVAL = 5; { Return semvals into arg.array (READ) } |
22 |
SEM_GETALL = 6; { Return the value of semzcnt (READ) } |
23 |
SEM_GETZCNT = 7; { Set the value of semval to arg.val (ALTER) } |
24 |
SEM_SETVAL = 8; { Set semvals from arg.array (ALTER) } |
25 |
SEM_SETALL = 9; |
26 |
{$ENDIF} |
27 |
{$ENDIF} |
28 |
|
29 |
function GetLastErrno: cint; |
30 |
begin |
31 |
Result := fpgetErrno |
32 |
end; |
33 |
|
34 |
type |
35 |
{Interprocess Communication Objects. All platform dependent IPC is abstracted |
36 |
into this set of objects } |
37 |
|
38 |
{ TIpcCommon } |
39 |
|
40 |
TIpcCommon = class(TInterfacedObject) |
41 |
public |
42 |
function GetSa: PSecurityAttributes; |
43 |
property Sa : PSecurityAttributes read GetSa; |
44 |
end; |
45 |
|
46 |
{ TSharedMemory } |
47 |
|
48 |
{ |
49 |
The shared memory segment is used for interprocess communication and |
50 |
holds both a message buffer and a number of shared variables. Shared |
51 |
memory is allocated to each shared variable using the Allocate function. |
52 |
An underlying assumption is that each process using the shared memory |
53 |
calls "Allocate" in the same order and for the same memory sizes. |
54 |
|
55 |
Linux: |
56 |
|
57 |
The Linux implementation uses Linux shared memory. IPC_PRIVATE is used |
58 |
to allocate the memory and the resulting memory id is written to a |
59 |
well known file. By default this is in the current user's home directory, |
60 |
but this can be over-ridden to specify a globally unique filename. |
61 |
|
62 |
Access to the shared memory is restricted to the current user/group. |
63 |
Note that the Linux semaphore set is also created with the shared memory. |
64 |
} |
65 |
|
66 |
ISharedMemory = interface |
67 |
['{db77bdd4-233a-4c9c-9212-dd7945e2e57c}'] |
68 |
function IsInitialiser: boolean; |
69 |
function Allocate(Size: integer): PByte; |
70 |
function GetLastAllocationSize: integer; |
71 |
function sem_op(SemNum, op: integer; flags: cshort = 0): cint; |
72 |
function sem_timedop(SemNum, op: integer; timeout_secs: integer; flags: cshort = 0): cint; |
73 |
function GetSemValue(SemNum: integer): cint; |
74 |
procedure SemInit(SemNum, AValue: cint); |
75 |
property LastAllocationSize: integer read GetLastAllocationSize; |
76 |
end; |
77 |
|
78 |
TSharedMemory = class(TIpcCommon,ISharedMemory) |
79 |
private |
80 |
FSharedMemoryID: cint; |
81 |
FSemaphoreSetID: cint; |
82 |
FBuffer: PByte; |
83 |
FLastAllocationSize: integer; |
84 |
FUnused: integer; |
85 |
FBufptr: PByte; |
86 |
FIPCFileName: AnsiString; |
87 |
FInitialiser: boolean; |
88 |
procedure DropSharedMemory; |
89 |
procedure GetSharedMemory(MemSize: integer); |
90 |
public |
91 |
constructor Create(MemSize: integer); |
92 |
destructor Destroy; override; |
93 |
function Allocate(Size: integer): PByte; |
94 |
function GetLastAllocationSize: integer; |
95 |
function IsInitialiser: boolean; |
96 |
function sem_op(SemNum, op: integer; flags: cshort = 0): cint; |
97 |
function sem_timedop(SemNum, op: integer; timeout_secs: integer; flags: cshort = 0): cint; |
98 |
function GetSemValue(SemNum: integer): cint; |
99 |
procedure SemInit(SemNum, AValue: cint); |
100 |
property LastAllocationSize: integer read GetLastAllocationSize; |
101 |
end; |
102 |
|
103 |
{TMutex} |
104 |
|
105 |
TMutex = class(TIpcCommon,IMutex) |
106 |
private |
107 |
FSharedMemory: ISharedMemory; |
108 |
FMutexSemaphore: cint; |
109 |
FLockCount: integer; |
110 |
public |
111 |
constructor Create(SemNumber: cint; sm: ISharedMemory); |
112 |
procedure Lock; |
113 |
procedure Unlock; |
114 |
end; |
115 |
|
116 |
{ TSingleLockGate } |
117 |
|
118 |
{ |
119 |
A single lock gate is either open or closed. When open, any thread can pass |
120 |
through it while, when closed, all threads are blocked as they try to pass |
121 |
through the gate. When the gate is opened, all blocked threads are resumed. |
122 |
|
123 |
There is an implementation assumption that only one writer thread at |
124 |
a time (i.e. the thread which locks or unlocks the gate) can have access to |
125 |
it at any one time. I.e. an external Mutex prevents race conditions. |
126 |
|
127 |
Linux: |
128 |
|
129 |
In the Linux implementation, the gate is implemented by a semaphore |
130 |
and a share memory integer used as a bi-state variable. When the gate |
131 |
is open, the bi-state variable is non-zero. It is set to zero when closed. |
132 |
Another shared memory integer is used to count the number of waiting |
133 |
threads, and a second semaphore is used to protect access to this. |
134 |
|
135 |
The event semaphore is initialised to zero. When a thread passes through the gate |
136 |
it checks the state. If open, the thread continues. If closed then it |
137 |
increments the count of waiting threads and then decrements the semaphore |
138 |
and hence enters an indefinite wait state. |
139 |
|
140 |
When the gate is locked, the state is set to zero. When unlocked, the state |
141 |
is set to one and the semaphore incremented by the number of waiting threads, |
142 |
which itself is then zeroed. |
143 |
|
144 |
Always initialised to the Unlocked state |
145 |
} |
146 |
|
147 |
TSingleLockGate = class(TIpcCommon,ISingleLockGate) |
148 |
private |
149 |
FSharedMemory: ISharedMemory; |
150 |
FSemaphore: cint; |
151 |
FMutex: cint; |
152 |
FSignalledState: PInteger; |
153 |
FWaitingThreads: PInteger; |
154 |
function GetWaitingThreads: integer; |
155 |
public |
156 |
constructor Create(SemNum: cint; sm: ISharedMemory); |
157 |
property WaitingThreads: integer read GetWaitingThreads; |
158 |
public |
159 |
procedure PassthroughGate; |
160 |
procedure Unlock; |
161 |
procedure Lock; |
162 |
end; |
163 |
|
164 |
{ TMultilockGate } |
165 |
|
166 |
{ This type of Gate is used where several reader threads must pass |
167 |
through the gate before it can be opened for a writer thread. |
168 |
|
169 |
The reader threads register their interest by each locking the gate. |
170 |
The writer thread then waits on the locked gate until all the reader |
171 |
threads have separately unlocked the gate. |
172 |
|
173 |
There is an underlying assumption of a single writer. A Mutex must |
174 |
be used to control access to the gate from the writer side if this |
175 |
assumption is invalid. |
176 |
|
177 |
Linux: |
178 |
|
179 |
The Linux implementation uses a single semaphore to implement the gate, |
180 |
which is initialised to 1 (unlocked), and a count of the number of |
181 |
threads that have locked the gate (LockCount). A mutex semaphore |
182 |
protects access to the LockCount. When the gate is locked, the lockcount |
183 |
is incremented and, if the LockCount was originally zero, the semaphore is |
184 |
set to zero (Gate Closed). |
185 |
|
186 |
Unlocking the gate, is the reverse. The LockCount is decremented and, if it |
187 |
reaches zero, the semaphore is set to one (Gate Opened). |
188 |
|
189 |
When a writer passes through the gate, it checks the LockCount, if zero it |
190 |
proceeds to pass through the gate. Otherwise it decrements and waits on the |
191 |
semaphore. When the writer resumes, it increments the semaphore in order |
192 |
to return it to its unlocked state. The wait is a timed wait, as there is |
193 |
a risk that a reader thread may terminate while the gate is locked. If the |
194 |
LockCount is non-zero, it is decremented and the writer returns to wait on |
195 |
the gate. |
196 |
|
197 |
Always initialised to the Unlocked state |
198 |
} |
199 |
|
200 |
TMultilockGate = class(TIpcCommon,IMultiLockGate) |
201 |
private |
202 |
FSharedMemory: ISharedMemory; |
203 |
FOnGateTimeout: TNotifyEvent; |
204 |
FSemaphore: cint; |
205 |
FMutex: cint; |
206 |
FLockCount: PInteger; |
207 |
function GetLockCount: integer; |
208 |
public |
209 |
constructor Create(SemNum: cint; sm: ISharedMemory); |
210 |
procedure Lock; |
211 |
procedure Unlock; |
212 |
procedure PassthroughGate; |
213 |
function GetOnGateTimeout: TNotifyEvent; |
214 |
procedure SetOnGateTimeout(AValue: TNotifyEvent); |
215 |
property LockCount: integer read GetLockCount; |
216 |
property OnGateTimeout: TNotifyEvent read GetOnGateTimeout write SetOnGateTimeout; |
217 |
end; |
218 |
|
219 |
{ TIPCInterface } |
220 |
|
221 |
TIPCInterface = class(TIpcCommon,IIPCInterface) |
222 |
private |
223 |
FMaxBufferSize: integer; |
224 |
FSharedMemory: ISharedMemory; |
225 |
FWriteLock: IMutex; |
226 |
FBuffer: PByte; |
227 |
FTraceDataType, |
228 |
FBufferSize: PInteger; |
229 |
FTimeStamp: PDateTime; |
230 |
FMsgNumber: PInteger; |
231 |
FReadReadyEvent: IMultiLockGate; |
232 |
FReadFinishedEvent: IMultiLockGate; |
233 |
FDataAvailableEvent: ISingleLockGate; |
234 |
FWriterBusyEvent: ISingleLockGate; |
235 |
public |
236 |
constructor Create; |
237 |
procedure IncMonitorCount; |
238 |
procedure DecMonitorCount; |
239 |
procedure SendTrace(TraceObject: TTraceObject); |
240 |
procedure ReceiveTrace(TraceObject: TTraceObject); |
241 |
function GetDataAvailableEvent: ISingleLockGate; |
242 |
function GetWriterBusyEvent: ISingleLockGate; |
243 |
function GetReadReadyEvent: IMultiLockGate; |
244 |
function GetReadFinishedEvent: IMultiLockGate; |
245 |
function GetWriteLock: IMutex; |
246 |
function GetMonitorCount: integer; |
247 |
function GetMaxBufferSize: integer; |
248 |
property DataAvailableEvent: ISingleLockGate read GetDataAvailableEvent; |
249 |
property WriterBusyEvent: ISingleLockGate read GetWriterBusyEvent; |
250 |
property ReadReadyEvent: IMultiLockGate read GetReadReadyEvent; |
251 |
property ReadFinishedEvent: IMultiLockGate read GetReadFinishedEvent; |
252 |
property WriteLock: IMutex read GetWriteLock; |
253 |
property MonitorCount: integer read GetMonitorCount; |
254 |
property MaxBufferSize: integer read GetMaxBufferSize; |
255 |
end; |
256 |
|
257 |
{ TSharedMemory } |
258 |
|
259 |
procedure TSharedMemory.GetSharedMemory(MemSize: integer); |
260 |
var F: cint; |
261 |
begin |
262 |
if GetEnvironmentVariable('FBSQL_IPCFILENAME') <> '' then |
263 |
FIPCFileName := GetEnvironmentVariable('FBSQL_IPCFILENAME') |
264 |
else |
265 |
FIPCFileName := GetTempDir(true) + IPCFileName + '.' + GetEnvironmentVariable('USER'); |
266 |
|
267 |
{Get the Shared Memory and Semaphore IDs from the Global File if it exists |
268 |
or create them and the file otherwise } |
269 |
|
270 |
repeat |
271 |
F := fpOpen(FIPCFileName, O_WrOnly or O_Creat or O_Excl); |
272 |
if F < 0 then |
273 |
begin |
274 |
if fpgetErrno = ESysEEXIST {EEXIST} then |
275 |
begin |
276 |
{ looks like it already exists} |
277 |
Sleep(100); |
278 |
F := fpOpen(FIPCFileName,O_RdOnly); |
279 |
if (F < 0) and (fpgetErrno = ESysENOENT {ENOENT}) then |
280 |
{probably just got deleted } |
281 |
else |
282 |
if F < 0 then |
283 |
IBError(ibxeCannotCreateSharedResource,['Error accessing IPC File - ' + |
284 |
StrError(fpgetErrno)]); |
285 |
end |
286 |
else |
287 |
IBError(ibxeCannotCreateSharedResource,['Error creating IPC File - ' + |
288 |
StrError(fpgetErrno)]); |
289 |
end |
290 |
else |
291 |
FInitialiser := true |
292 |
until F >= 0; |
293 |
|
294 |
if FInitialiser then |
295 |
begin |
296 |
FSharedMemoryID := shmget(IPC_PRIVATE,MemSize, IPC_CREAT or |
297 |
S_IRUSR or S_IWUSR or S_IRGRP or S_IWGRP); |
298 |
if FSharedMemoryID < 0 then |
299 |
IBError(ibxeCannotCreateSharedResource,['Cannot create shared memory segment - ' + |
300 |
StrError(fpgetErrno)]); |
301 |
|
302 |
FSemaphoreSetID := semget(IPC_PRIVATE, cNumberOfSemaphores,IPC_CREAT or |
303 |
S_IRUSR or S_IWUSR or S_IRGRP or S_IWGRP); |
304 |
if FSemaphoreSetID < 0 then |
305 |
IBError(ibxeCannotCreateSharedResource,['Cannot create shared semaphore set - ' + |
306 |
StrError(fpgetErrno)]); |
307 |
|
308 |
fpWrite(F,FSharedMemoryID,sizeof(FSharedMemoryID)); |
309 |
fpWrite(F,FSemaphoreSetID,sizeof(FSemaphoreSetID)); |
310 |
end |
311 |
else |
312 |
begin |
313 |
fpRead(F,FSharedMemoryID,sizeof(FSharedMemoryID)); |
314 |
fpRead(F,FSemaphoreSetID,sizeof(FSemaphoreSetID)); |
315 |
if GetSemValue(cMonitorCounter) = 0 then |
316 |
begin |
317 |
FInitialiser := true; |
318 |
//writeln('Opened file and is initialiser'); |
319 |
end |
320 |
end; |
321 |
fpClose(F); |
322 |
end; |
323 |
|
324 |
procedure TSharedMemory.DropSharedMemory; |
325 |
var ds: TShmid_ds; |
326 |
arg: tsemun; |
327 |
begin |
328 |
if shmctl(FSharedMemoryID,IPC_STAT,@ds) < 0 then |
329 |
IBError(ibxeSV5APIError,['Error getting shared memory info' + strError(fpgetErrno)]); |
330 |
if ds.shm_nattch = 0 then { we are the last one out - so, turn off the lights } |
331 |
begin |
332 |
shmctl(FSharedMemoryID,IPC_RMID,nil); |
333 |
semctl(FSemaphoreSetID,0,IPC_RMID,arg); |
334 |
DeleteFile(FIPCFileName); |
335 |
end; |
336 |
end; |
337 |
|
338 |
constructor TSharedMemory.Create(MemSize: integer); |
339 |
begin |
340 |
inherited Create; |
341 |
FInitialiser := false; |
342 |
GetSharedMemory(MemSize); |
343 |
FBuffer := shmat(FSharedMemoryID,nil,0); |
344 |
if PtrInt(FBuffer) = -1 then |
345 |
IBError(ibxeCannotCreateSharedResource,[StrError(Errno)]); |
346 |
FBufPtr := FBuffer; |
347 |
FUnused := MemSize |
348 |
end; |
349 |
|
350 |
destructor TSharedMemory.Destroy; |
351 |
begin |
352 |
shmdt(FBuffer); |
353 |
DropSharedMemory; |
354 |
inherited Destroy; |
355 |
end; |
356 |
|
357 |
function TSharedMemory.Allocate(Size: integer): PByte; |
358 |
begin |
359 |
if Size > FUnused then |
360 |
IBError(ibxeCannotCreateSharedResource, ['Not enough shared memory']); |
361 |
Result := FBufPtr; |
362 |
|
363 |
if Size = 0 then |
364 |
begin |
365 |
FLastAllocationSize := FUnused; |
366 |
FUnused := 0 |
367 |
end |
368 |
else |
369 |
begin |
370 |
FLastAllocationSize := Size; |
371 |
Dec(FUnused,Size); |
372 |
end; |
373 |
Inc(FBufPtr,Size) |
374 |
end; |
375 |
|
376 |
function TSharedMemory.GetLastAllocationSize: integer; |
377 |
begin |
378 |
Result := FLastAllocationSize; |
379 |
end; |
380 |
|
381 |
function TSharedMemory.IsInitialiser: boolean; |
382 |
begin |
383 |
Result := FInitialiser; |
384 |
end; |
385 |
|
386 |
function TSharedMemory.sem_op(SemNum, op: integer; flags: cshort): cint; |
387 |
var sembuf: TSEMbuf; |
388 |
begin |
389 |
sembuf.sem_num := SemNum; |
390 |
sembuf.sem_op:= op; |
391 |
sembuf.sem_flg := flags or SEM_UNDO; |
392 |
Result := semop(FSemaphoreSetID,@sembuf,1); |
393 |
end; |
394 |
|
395 |
function TSharedMemory.sem_timedop(SemNum, op: integer; timeout_secs: integer; |
396 |
flags: cshort): cint; |
397 |
var sembuf: TSEMbuf; |
398 |
timeout: TimeSpec; |
399 |
begin |
400 |
sembuf.sem_num := SemNum; |
401 |
sembuf.sem_op:= op; |
402 |
sembuf.sem_flg := flags or SEM_UNDO; |
403 |
timeout.tv_sec := timeout_secs; |
404 |
timeout.tv_nsec := 0; |
405 |
{$IF declared(semtimedop)} |
406 |
Result := semtimedop(FSemaphoreSetID,@sembuf,1,@timeout); |
407 |
{$ELSE} |
408 |
Result := semop(FSemaphoreSetID,@sembuf,1); {May hang on race condition} |
409 |
{$IFEND} |
410 |
end; |
411 |
|
412 |
function TSharedMemory.GetSemValue(SemNum: integer): cint; |
413 |
var args :TSEMun; |
414 |
begin |
415 |
Result := semctl(FSemaphoreSetID,SemNum,SEM_GETVAL,args); |
416 |
if Result < 0 then |
417 |
IBError(ibxeSV5APIError,['GetSemValue: '+strError(GetLastErrno)]); |
418 |
end; |
419 |
|
420 |
procedure TSharedMemory.SemInit(SemNum, AValue: cint); |
421 |
var args :TSEMun; |
422 |
begin |
423 |
//writeln('Initialising ',SemNum,' to ',AValue); |
424 |
args.val := AValue; |
425 |
if semctl(FSemaphoreSetID,SemNum,SEM_SETVAL,args) < 0 then |
426 |
IBError(ibxeCannotCreateSharedResource,['Unable to initialise Semaphone ' + |
427 |
IntToStr(SemNum) + '- ' + StrError(GetLastErrno)]); |
428 |
|
429 |
end; |
430 |
|
431 |
{ TIpcCommon } |
432 |
|
433 |
function TIpcCommon.GetSa: PSecurityAttributes; |
434 |
begin |
435 |
Result := nil |
436 |
end; |
437 |
|
438 |
{ TMutex } |
439 |
|
440 |
constructor TMutex.Create(SemNumber: cint; sm: ISharedMemory); |
441 |
begin |
442 |
inherited Create; |
443 |
FSharedMemory := sm; |
444 |
FMutexSemaphore := SemNumber; |
445 |
if FSharedMemory.IsInitialiser then |
446 |
FSharedMemory.SemInit(FMutexSemaphore,1) |
447 |
end; |
448 |
|
449 |
{ Obtain ownership of the Mutex and prevent other threads from accessing protected resource } |
450 |
|
451 |
procedure TMutex.Lock; |
452 |
begin |
453 |
//writeln('Lock: Entering Mutex ',FMutexSemaphore,' LockCount=',FLockCount,' State = ',GetSemValue(FMutexSemaphore)); |
454 |
if FLockCount = 0 then |
455 |
FSharedMemory.sem_op(FMutexSemaphore,-1); |
456 |
Inc(FLockCount); |
457 |
//writeln('Lock: Mutex Exit'); |
458 |
end; |
459 |
|
460 |
{Give up ownership of the Mutex and allow other threads access } |
461 |
|
462 |
procedure TMutex.Unlock; |
463 |
begin |
464 |
//writeln('UnLock: Entering Mutex, LockCount=',FLockCount); |
465 |
if FLockCount = 0 then Exit; |
466 |
Dec(FLockCount); |
467 |
if FLockCount = 0 then |
468 |
FSharedMemory.sem_op(FMutexSemaphore,1); |
469 |
//writeln('UnLock: Mutex Exit',' State = ',GetSemValue(FMutexSemaphore)); |
470 |
end; |
471 |
|
472 |
{ TSingleLockGate } |
473 |
|
474 |
function TSingleLockGate.GetWaitingThreads: integer; |
475 |
begin |
476 |
Result := FWaitingThreads^ |
477 |
end; |
478 |
|
479 |
constructor TSingleLockGate.Create(SemNum: cint; sm: ISharedMemory); |
480 |
begin |
481 |
inherited Create; |
482 |
FSharedMemory := sm; |
483 |
FSignalledState := PInteger(FSharedMemory.Allocate(sizeof(FSignalledState))); |
484 |
FWaitingThreads := PInteger(FSharedMemory.Allocate(sizeof(FWaitingThreads))); |
485 |
FSemaphore := SemNum; |
486 |
FMutex := SemNum + 1; |
487 |
if FSharedMemory.IsInitialiser then |
488 |
begin |
489 |
FSignalledState^ := 1; |
490 |
FWaitingThreads^ := 0; |
491 |
FSharedMemory.SemInit(FSemaphore,0); |
492 |
FSharedMemory.SemInit(FMutex,1); |
493 |
end; |
494 |
end; |
495 |
|
496 |
procedure TSingleLockGate.PassthroughGate; |
497 |
begin |
498 |
if FSignalledState^ = 0 then |
499 |
begin |
500 |
FSharedMemory.sem_op(FMutex,-1,0); //Acquire Mutex |
501 |
Inc(FWaitingThreads^); |
502 |
FSharedMemory.sem_op(FMutex,1,0); //Release Mutex |
503 |
//writeln(ClassName + ': Wait State Entered ',FSemaphore,' = ',GetSemValue(FSemaphore)); |
504 |
FSharedMemory.sem_op(FSemaphore,-1,0); //Enter Wait |
505 |
//writeln(ClassName + ': Wait State Ends ',FSemaphore); |
506 |
end; |
507 |
end; |
508 |
|
509 |
procedure TSingleLockGate.Unlock; |
510 |
begin |
511 |
if FSignalledState^ = 0 then |
512 |
begin |
513 |
FSignalledState^ := 1; |
514 |
FSharedMemory.sem_op(FMutex,-1,0); //Acquire Mutex |
515 |
{$IFDEF DEBUG}writeln(ClassName + ': Unlocking' ,FSemaphore);{$ENDIF} |
516 |
FSharedMemory.sem_op(FSemaphore,FWaitingThreads^,0); |
517 |
FWaitingThreads^ := 0; |
518 |
FSharedMemory.sem_op(FMutex,1,0); //Release Mutex |
519 |
end; |
520 |
end; |
521 |
|
522 |
procedure TSingleLockGate.Lock; |
523 |
begin |
524 |
if FSignalledState^ = 1 then |
525 |
begin |
526 |
{$IFDEF DEBUG}writeln(ClassName + ': Locking Gate ',FSemaphore);{$ENDIF} |
527 |
FSharedMemory.SemInit(FSemaphore,0); |
528 |
FSignalledState^ := 0; |
529 |
end; |
530 |
end; |
531 |
|
532 |
{ TMultilockGate } |
533 |
|
534 |
constructor TMultilockGate.Create(SemNum: cint; sm: ISharedMemory); |
535 |
begin |
536 |
inherited Create; |
537 |
FSemaphore := SemNum; |
538 |
FMutex := SemNum + 1; |
539 |
FSharedMemory := sm; |
540 |
FLockCount := PInteger(FSharedMemory.Allocate(sizeof(FLockCount))); |
541 |
if FSharedMemory.IsInitialiser then |
542 |
begin |
543 |
FLockCount^ := 0; |
544 |
FSharedMemory.SemInit(FSemaphore,1); |
545 |
FSharedMemory.SemInit(FMutex,1); |
546 |
end; |
547 |
end; |
548 |
|
549 |
function TMultilockGate.GetLockCount: integer; |
550 |
begin |
551 |
Result := FLockCount^ |
552 |
end; |
553 |
|
554 |
function TMultilockGate.GetOnGateTimeout: TNotifyEvent; |
555 |
begin |
556 |
Result := FOnGateTimeout; |
557 |
end; |
558 |
|
559 |
procedure TMultilockGate.SetOnGateTimeout(AValue: TNotifyEvent); |
560 |
begin |
561 |
FOnGateTimeout := AValue; |
562 |
end; |
563 |
|
564 |
procedure TMultilockGate.Lock; |
565 |
begin |
566 |
FSharedMemory.sem_op(FMutex,-1,0); //Acquire Mutex |
567 |
if FLockCount^ = 0 then |
568 |
begin |
569 |
{$IFDEF DEBUG}writeln(ClassName,': Locking ',FSemaphore);{$ENDIF} |
570 |
FSharedMemory.SemInit(FSemaphore,0); |
571 |
end; |
572 |
Inc(FLockCount^); |
573 |
FSharedMemory.sem_op(FMutex,1,0); //Release Mutex |
574 |
end; |
575 |
|
576 |
procedure TMultilockGate.Unlock; |
577 |
begin |
578 |
FSharedMemory.sem_op(FMutex,-1,0); //Acquire Mutex |
579 |
Dec(FLockCount^); |
580 |
if FLockCount^ <= 0 then |
581 |
begin |
582 |
{$IFDEF DEBUG}writeln(ClassName,': UnLocking ',FSemaphore);{$ENDIF} |
583 |
FSharedMemory.SemInit(FSemaphore,1); |
584 |
FLockCount^ := 0 |
585 |
end; |
586 |
FSharedMemory.sem_op(FMutex,1,0); //Release Mutex |
587 |
end; |
588 |
|
589 |
procedure TMultilockGate.PassthroughGate; |
590 |
begin |
591 |
if FLockCount^ = 0 then |
592 |
Exit; |
593 |
{$IFDEF DEBUG}writeln(ClassName,': Waiting on ',FSemaphore);{$ENDIF} |
594 |
while FSharedMemory.sem_timedop(FSemaphore,-1,cDefaultTimeout) < 0 do |
595 |
{looks like we lost a reader} |
596 |
begin |
597 |
{$IFDEF DEBUG}writeln(ClassName,': reader lost timeout');{$ENDIF} |
598 |
if FLockCount^ > 0 then |
599 |
begin |
600 |
UnLock; |
601 |
if assigned(FOnGateTimeout) then |
602 |
OnGateTimeout(self) |
603 |
end |
604 |
end; |
605 |
FSharedMemory.sem_op(FSemaphore,1); |
606 |
{$IFDEF DEBUG}writeln(ClassName,': Wait done on ',FSemaphore);{$ENDIF} |
607 |
end; |
608 |
|
609 |
|
610 |
{ TIPCInterface } |
611 |
|
612 |
function TIPCInterface.GetMonitorCount: integer; |
613 |
begin |
614 |
Result := FSharedMemory.GetSemValue(cMonitorCounter) |
615 |
end; |
616 |
|
617 |
function TIPCInterface.GetMaxBufferSize: integer; |
618 |
begin |
619 |
Result := FMaxBufferSize; |
620 |
end; |
621 |
|
622 |
constructor TIPCInterface.Create; |
623 |
begin |
624 |
inherited Create; |
625 |
FSharedMemory := TSharedMemory.Create(cMonitorHookSize); |
626 |
|
627 |
FWriteLock := TMutex.Create(cMutexSemaphore,FSharedMemory); |
628 |
|
629 |
FDataAvailableEvent := TSingleLockGate.Create(cDataAvailableEventSemaphore,FSharedMemory); |
630 |
FWriterBusyEvent := TSingleLockGate.Create(cWriterBusyEventSemaphore,FSharedMemory); |
631 |
FReadReadyEvent := TMultiLockGate.Create(cReadReadyEventSemaphore,FSharedMemory); |
632 |
FReadFinishedEvent := TMultiLockGate.Create(cReadFinishedEventSemaphore,FSharedMemory); |
633 |
|
634 |
if FSharedMemory.IsInitialiser then |
635 |
FSharedMemory.SemInit(cMonitorCounter,0); |
636 |
FTraceDataType := PInteger(FSharedMemory.Allocate(sizeof(Integer))); |
637 |
FTimeStamp := PDateTime(FSharedMemory.Allocate(sizeof(TDateTime))); |
638 |
FBufferSize := PInteger(FSharedMemory.Allocate(sizeof(Integer))); |
639 |
FMsgNumber := PInteger(FSharedMemory.Allocate(sizeof(Integer))); |
640 |
FBuffer := FSharedMemory.Allocate(0); //All remaining |
641 |
FMaxBufferSize := FSharedMemory.LastAllocationSize; |
642 |
|
643 |
if FSharedMemory.IsInitialiser then |
644 |
begin |
645 |
FBufferSize^ := 0; |
646 |
FDataAvailableEvent.Lock; |
647 |
FMsgNumber^ := 0; |
648 |
end; |
649 |
end; |
650 |
|
651 |
procedure TIPCInterface.IncMonitorCount; |
652 |
begin |
653 |
FSharedMemory.sem_op(cMonitorCounter,1); |
654 |
end; |
655 |
|
656 |
procedure TIPCInterface.DecMonitorCount; |
657 |
begin |
658 |
FSharedMemory.sem_op(cMonitorCounter,-1,IPC_NOWAIT); |
659 |
end; |
660 |
|
661 |
procedure TIPCInterface.SendTrace(TraceObject: TTraceObject); |
662 |
begin |
663 |
FTraceDataType^ := Integer(TraceObject.FDataType); |
664 |
FTimeStamp^ := TraceObject.FTimeStamp; |
665 |
if Length(TraceObject.FMsg) > MaxBufferSize then |
666 |
FBufferSize^ := MaxBufferSize |
667 |
else |
668 |
FBufferSize^ := Length(TraceObject.FMsg); |
669 |
FMsgNumber^ := TraceObject.FMsgNumber; |
670 |
Move(TraceObject.FMsg[1], FBuffer^, FBufferSize^); |
671 |
end; |
672 |
|
673 |
procedure TIPCInterface.ReceiveTrace(TraceObject: TTraceObject); |
674 |
begin |
675 |
SetString(TraceObject.FMsg, PAnsiChar(FBuffer), FBufferSize^); |
676 |
TraceObject.FDataType := TTraceFlag(FTraceDataType^); |
677 |
TraceObject.FTimeStamp := TDateTime(FTimeStamp^); |
678 |
TraceObject.FMsgNumber := FMsgNumber^; |
679 |
end; |
680 |
|
681 |
function TIPCInterface.GetDataAvailableEvent: ISingleLockGate; |
682 |
begin |
683 |
Result := FDataAvailableEvent; |
684 |
end; |
685 |
|
686 |
function TIPCInterface.GetWriterBusyEvent: ISingleLockGate; |
687 |
begin |
688 |
Result := FWriterBusyEvent; |
689 |
end; |
690 |
|
691 |
function TIPCInterface.GetReadReadyEvent: IMultiLockGate; |
692 |
begin |
693 |
Result := FReadReadyEvent; |
694 |
end; |
695 |
|
696 |
function TIPCInterface.GetReadFinishedEvent: IMultiLockGate; |
697 |
begin |
698 |
Result := FReadFinishedEvent; |
699 |
end; |
700 |
|
701 |
function TIPCInterface.GetWriteLock: IMutex; |
702 |
begin |
703 |
Result := FWriteLock; |
704 |
end; |
705 |
|
706 |
|
707 |
|