1 |
{Used by ISQLMonitor and implements System V IPC}
|
2 |
|
3 |
const
|
4 |
IPCFileName: string = 'FB.SQL.MONITOR1_0';
|
5 |
cNumberOfSemaphores = 10;
|
6 |
cMutexSemaphore = 0;
|
7 |
cMonitorCounter = 1;
|
8 |
cReadReadyEventSemaphore = 2;
|
9 |
cReadFinishedEventSemaphore = 4;
|
10 |
cDataAvailableEventSemaphore = 6;
|
11 |
cWriterBusyEventSemaphore = 8;
|
12 |
cDefaultTimeout = 1; { 1 seconds }
|
13 |
|
14 |
{
|
15 |
The call to semctl in ipc is broken in FPC release 2.4.2 and earlier. Hence
|
16 |
need to replace with a working libc call. semtimedop is not present in 2.4.2 and earlier.
|
17 |
}
|
18 |
|
19 |
{$IF FPC_FULLVERSION <= 20402 }
|
20 |
Function real_semctl(semid:cint; semnum:cint; cmd:cint): cint; cdecl; varargs; external clib name 'semctl';
|
21 |
|
22 |
Function semctl(semid:cint; semnum:cint; cmd:cint; var arg: tsemun): cint;
|
23 |
begin
|
24 |
semctl := real_semctl(semid,semnum,cmd,pointer(arg));
|
25 |
end;
|
26 |
{$IFDEF HAS_SEMTIMEDOP}
|
27 |
Function semtimedop(semid:cint; sops: psembuf; nsops: cuint; timeOut: ptimespec): cint; cdecl; external clib name 'semtimedop';
|
28 |
{$ENDIF}
|
29 |
Function semget(key:Tkey; nsems:cint; semflg:cint): cint; cdecl; external clib name 'semget';
|
30 |
Function semop(semid:cint; sops: psembuf; nsops: cuint): cint; cdecl; external clib name 'semop';
|
31 |
|
32 |
function GetLastErrno: cint;
|
33 |
begin
|
34 |
Result := fpgetCerrno
|
35 |
end;
|
36 |
{$ELSE}
|
37 |
function GetLastErrno: cint;
|
38 |
begin
|
39 |
Result := fpgetErrno
|
40 |
end;
|
41 |
|
42 |
{$ENDIF}
|
43 |
|
44 |
type
|
45 |
TGlobalInterface = class;
|
46 |
{Interprocess Communication Objects. All platform dependent IPC is abstracted
|
47 |
into this set of objects }
|
48 |
|
49 |
{ TIpcCommon }
|
50 |
|
51 |
TIpcCommon = class
|
52 |
private
|
53 |
function GetSa: PSecurityAttributes;
|
54 |
protected
|
55 |
FInitialiser: boolean; static;
|
56 |
FSemaphoreSetID: cint; static;
|
57 |
FSharedMemoryID: cint; static;
|
58 |
function sem_op(SemNum, op: integer; flags: cshort = 0): cint;
|
59 |
function sem_timedop(SemNum, op: integer; timeout_secs: integer; flags: cshort = 0): cint;
|
60 |
function GetSemValue(SemNum: integer): cint;
|
61 |
procedure SemInit(SemNum, AValue: cint);
|
62 |
public
|
63 |
property Sa : PSecurityAttributes read GetSa;
|
64 |
end;
|
65 |
|
66 |
{ TSharedMemory }
|
67 |
|
68 |
{
|
69 |
The shared memory segment is used for interprocess communication and
|
70 |
holds both a message buffer and a number of shared variables. Shared
|
71 |
memory is allocated to each shared variable using the Allocate function.
|
72 |
An underlying assumption is that each process using the shared memory
|
73 |
calls "Allocate" in the same order and for the same memory sizes.
|
74 |
|
75 |
Linux:
|
76 |
|
77 |
The Linux implementation uses Linux shared memory. IPC_PRIVATE is used
|
78 |
to allocate the memory and the resulting memory id is written to a
|
79 |
well known file. By default this is in the current user's home directory,
|
80 |
but this can be over-ridden to specify a globally unique filename.
|
81 |
|
82 |
Access to the shared memory is restricted to the current user/group.
|
83 |
Note that the Linux semaphore set is also created with the shared memory.
|
84 |
}
|
85 |
|
86 |
TSharedMemory = class(TIpcCommon)
|
87 |
private
|
88 |
FBuffer: PChar;
|
89 |
FLastAllocationSize: integer;
|
90 |
FUnused: integer;
|
91 |
FBufptr: PChar;
|
92 |
procedure DropSharedMemory;
|
93 |
procedure GetSharedMemory(MemSize: integer);
|
94 |
public
|
95 |
constructor Create(MemSize: integer);
|
96 |
destructor Destroy; override;
|
97 |
function Allocate(Size: integer): PChar;
|
98 |
property LastAllocationSize: integer read FLastAllocationSize;
|
99 |
end;
|
100 |
|
101 |
{TMutex}
|
102 |
|
103 |
TMutex = class(TIpcCommon)
|
104 |
private
|
105 |
FMutexSemaphore: cint;
|
106 |
FLockCount: integer;
|
107 |
public
|
108 |
constructor Create(SemNumber: cint);
|
109 |
procedure Lock;
|
110 |
procedure Unlock;
|
111 |
end;
|
112 |
|
113 |
{ TSingleLockGate }
|
114 |
|
115 |
{
|
116 |
A single lock gate is either open or closed. When open, any thread can pass
|
117 |
through it while, when closed, all threads are blocked as they try to pass
|
118 |
through the gate. When the gate is opened, all blocked threads are resumed.
|
119 |
|
120 |
There is an implementation assumption that only one writer thread at
|
121 |
a time (i.e. the thread which locks or unlocks the gate) can have access to
|
122 |
it at any one time. I.e. an external Mutex prevents race conditions.
|
123 |
|
124 |
Linux:
|
125 |
|
126 |
In the Linux implementation, the gate is implemented by a semaphore
|
127 |
and a share memory integer used as a bi-state variable. When the gate
|
128 |
is open, the bi-state variable is non-zero. It is set to zero when closed.
|
129 |
Another shared memory integer is used to count the number of waiting
|
130 |
threads, and a second semaphore is used to protect access to this.
|
131 |
|
132 |
The event semaphore is initialised to zero. When a thread passes through the gate
|
133 |
it checks the state. If open, the thread continues. If closed then it
|
134 |
increments the count of waiting threads and then decrements the semaphore
|
135 |
and hence enters an indefinite wait state.
|
136 |
|
137 |
When the gate is locked, the state is set to zero. When unlocked, the state
|
138 |
is set to one and the semaphore incremented by the number of waiting threads,
|
139 |
which itself is then zeroed.
|
140 |
|
141 |
Always initialised to the Unlocked state
|
142 |
}
|
143 |
|
144 |
TSingleLockGate = class(TIpcCommon)
|
145 |
private
|
146 |
FOwner: TGlobalInterface;
|
147 |
FSemaphore: cint;
|
148 |
FMutex: cint;
|
149 |
FSignalledState: PInteger;
|
150 |
FWaitingThreads: PInteger;
|
151 |
function GetWaitingThreads: integer;
|
152 |
public
|
153 |
constructor Create(SemNum: cint; AOwner: TGlobalInterface);
|
154 |
property WaitingThreads: integer read GetWaitingThreads;
|
155 |
public
|
156 |
procedure PassthroughGate;
|
157 |
procedure Unlock;
|
158 |
procedure Lock;
|
159 |
end;
|
160 |
|
161 |
{ TMultilockGate }
|
162 |
|
163 |
{ This type of Gate is used where several reader threads must pass
|
164 |
through the gate before it can be opened for a writer thread.
|
165 |
|
166 |
The reader threads register their interest by each locking the gate.
|
167 |
The writer thread then waits on the locked gate until all the reader
|
168 |
threads have separately unlocked the gate.
|
169 |
|
170 |
There is an underlying assumption of a single writer. A Mutex must
|
171 |
be used to control access to the gate from the writer side if this
|
172 |
assumption is invalid.
|
173 |
|
174 |
Linux:
|
175 |
|
176 |
The Linux implementation uses a single semaphore to implement the gate,
|
177 |
which is initialised to 1 (unlocked), and a count of the number of
|
178 |
threads that have locked the gate (LockCount). A mutex semaphore
|
179 |
protects access to the LockCount. When the gate is locked, the lockcount
|
180 |
is incremented and, if the LockCount was originally zero, the semaphore is
|
181 |
set to zero (Gate Closed).
|
182 |
|
183 |
Unlocking the gate, is the reverse. The LockCount is decremented and, if it
|
184 |
reaches zero, the semaphore is set to one (Gate Opened).
|
185 |
|
186 |
When a writer passes through the gate, it checks the LockCount, if zero it
|
187 |
proceeds to pass through the gate. Otherwise it decrements and waits on the
|
188 |
semaphore. When the writer resumes, it increments the semaphore in order
|
189 |
to return it to its unlocked state. The wait is a timed wait, as there is
|
190 |
a risk that a reader thread may terminate while the gate is locked. If the
|
191 |
LockCount is non-zero, it is decremented and the writer returns to wait on
|
192 |
the gate.
|
193 |
|
194 |
Always initialised to the Unlocked state
|
195 |
}
|
196 |
|
197 |
TMultilockGate = class(TIpcCommon)
|
198 |
private
|
199 |
FOnGateTimeout: TNotifyEvent;
|
200 |
FOwner: TGlobalInterface;
|
201 |
FSemaphore: cint;
|
202 |
FMutex: cint;
|
203 |
FLockCount: PInteger;
|
204 |
function GetLockCount: integer;
|
205 |
public
|
206 |
constructor Create(SemNum: cint; AOwner: TGlobalInterface);
|
207 |
procedure Lock;
|
208 |
procedure Unlock;
|
209 |
procedure PassthroughGate;
|
210 |
property LockCount: integer read GetLockCount;
|
211 |
property OnGateTimeout: TNotifyEvent read FOnGateTimeout write FOnGateTimeout;
|
212 |
end;
|
213 |
|
214 |
{ TGlobalInterface }
|
215 |
|
216 |
TGlobalInterface = class(TIpcCommon)
|
217 |
private
|
218 |
FMaxBufferSize: integer;
|
219 |
FSharedMemory: TSharedMemory;
|
220 |
FWriteLock: TMutex;
|
221 |
FBuffer: PChar;
|
222 |
FTraceDataType,
|
223 |
FBufferSize: PInteger;
|
224 |
FTimeStamp: PDateTime;
|
225 |
FReadReadyEvent: TMultiLockGate;
|
226 |
FReadFinishedEvent: TMultiLockGate;
|
227 |
FDataAvailableEvent: TSingleLockGate;
|
228 |
FWriterBusyEvent: TSingleLockGate;
|
229 |
function GetMonitorCount: integer;
|
230 |
public
|
231 |
constructor Create;
|
232 |
destructor Destroy; override;
|
233 |
procedure IncMonitorCount;
|
234 |
procedure DecMonitorCount;
|
235 |
procedure SendTrace(TraceObject: TTraceObject);
|
236 |
procedure ReceiveTrace(TraceObject: TTraceObject);
|
237 |
property DataAvailableEvent: TSingleLockGate read FDataAvailableEvent;
|
238 |
property WriterBusyEvent: TSingleLockGate read FWriterBusyEvent;
|
239 |
property ReadReadyEvent: TMultiLockGate read FReadReadyEvent;
|
240 |
property ReadFinishedEvent: TMultiLockGate read FReadFinishedEvent;
|
241 |
property WriteLock: TMutex read FWriteLock;
|
242 |
property MonitorCount: integer read GetMonitorCount;
|
243 |
property SharedMemory: TSharedMemory read FSharedMemory;
|
244 |
property MaxBufferSize: integer read FMaxBufferSize;
|
245 |
end;
|
246 |
|
247 |
{ TSharedMemory }
|
248 |
|
249 |
procedure TSharedMemory.GetSharedMemory(MemSize: integer);
|
250 |
var F: cint;
|
251 |
begin
|
252 |
{Get the Shared Memory and Semaphore IDs from the Global File if it exists
|
253 |
or create them and the file otherwise }
|
254 |
|
255 |
repeat
|
256 |
F := fpOpen(IPCFileName, O_WrOnly or O_Creat or O_Excl);
|
257 |
if F < 0 then
|
258 |
begin
|
259 |
if fpgetErrno = 17 {EEXIST} then
|
260 |
begin
|
261 |
{ looks like it already exists}
|
262 |
Sleep(100);
|
263 |
F := fpOpen(IPCFileName,O_RdOnly);
|
264 |
if (F < 0) and (fpgetErrno = 2 {ENOENT}) then
|
265 |
{probably just got deleted }
|
266 |
else
|
267 |
if F < 0 then
|
268 |
IBError(ibxeCannotCreateSharedResource,['Error accessing IPC File - ' +
|
269 |
StrError(fpgetErrno)]);
|
270 |
end
|
271 |
else
|
272 |
IBError(ibxeCannotCreateSharedResource,['Error creating IPC File - ' +
|
273 |
StrError(fpgetErrno)]);
|
274 |
end
|
275 |
else
|
276 |
FInitialiser := true
|
277 |
until F >= 0;
|
278 |
|
279 |
if FInitialiser then
|
280 |
begin
|
281 |
FSharedMemoryID := shmget(IPC_PRIVATE,MemSize, IPC_CREAT or
|
282 |
S_IRUSR or S_IWUSR or S_IRGRP or S_IWGRP);
|
283 |
if FSharedMemoryID < 0 then
|
284 |
IBError(ibxeCannotCreateSharedResource,['Cannot create shared memory segment - ' +
|
285 |
StrError(fpgetErrno)]);
|
286 |
|
287 |
FSemaphoreSetID := semget(IPC_PRIVATE, cNumberOfSemaphores,IPC_CREAT or
|
288 |
S_IRUSR or S_IWUSR or S_IRGRP or S_IWGRP);
|
289 |
if FSemaphoreSetID < 0 then
|
290 |
IBError(ibxeCannotCreateSharedResource,['Cannot create shared semaphore set - ' +
|
291 |
StrError(fpgetErrno)]);
|
292 |
|
293 |
fpWrite(F,FSharedMemoryID,sizeof(FSharedMemoryID));
|
294 |
fpWrite(F,FSemaphoreSetID,sizeof(FSemaphoreSetID));
|
295 |
end
|
296 |
else
|
297 |
begin
|
298 |
fpRead(F,FSharedMemoryID,sizeof(FSharedMemoryID));
|
299 |
fpRead(F,FSemaphoreSetID,sizeof(FSemaphoreSetID));
|
300 |
if GetSemValue(cMonitorCounter) = 0 then
|
301 |
begin
|
302 |
FInitialiser := true;
|
303 |
//writeln('Opened file and is initialiser');
|
304 |
end
|
305 |
end;
|
306 |
fpClose(F);
|
307 |
end;
|
308 |
|
309 |
procedure TSharedMemory.DropSharedMemory;
|
310 |
var ds: TShmid_ds;
|
311 |
arg: tsemun;
|
312 |
begin
|
313 |
if shmctl(FSharedMemoryID,IPC_STAT,@ds) < 0 then
|
314 |
IBError(ibxeSV5APIError,['Error getting shared memory info' + strError(fpgetErrno)]);
|
315 |
if ds.shm_nattch = 0 then { we are the last one out - so, turn off the lights }
|
316 |
begin
|
317 |
shmctl(FSharedMemoryID,IPC_RMID,nil);
|
318 |
semctl(FSemaphoreSetID,0,IPC_RMID,arg);
|
319 |
DeleteFile(IPCFileName);
|
320 |
end;
|
321 |
end;
|
322 |
|
323 |
constructor TSharedMemory.Create(MemSize: integer);
|
324 |
begin
|
325 |
inherited Create;
|
326 |
FInitialiser := false;
|
327 |
GetSharedMemory(MemSize);
|
328 |
FBuffer := shmat(FSharedMemoryID,nil,0);
|
329 |
if PtrInt(FBuffer) = -1 then
|
330 |
IBError(ibxeCannotCreateSharedResource,[StrError(Errno)]);
|
331 |
FBufPtr := FBuffer;
|
332 |
FUnused := MemSize
|
333 |
end;
|
334 |
|
335 |
destructor TSharedMemory.Destroy;
|
336 |
begin
|
337 |
shmdt(FBuffer);
|
338 |
DropSharedMemory;
|
339 |
inherited Destroy;
|
340 |
end;
|
341 |
|
342 |
function TSharedMemory.Allocate(Size: integer): PChar;
|
343 |
begin
|
344 |
if Size > FUnused then
|
345 |
IBError(ibxeCannotCreateSharedResource, ['Not enough shared memory']);
|
346 |
Result := FBufPtr;
|
347 |
|
348 |
if Size = 0 then
|
349 |
begin
|
350 |
FLastAllocationSize := FUnused;
|
351 |
FUnused := 0
|
352 |
end
|
353 |
else
|
354 |
begin
|
355 |
FLastAllocationSize := Size;
|
356 |
Dec(FUnused,Size);
|
357 |
end;
|
358 |
Inc(FBufPtr,Size)
|
359 |
end;
|
360 |
|
361 |
{ TIpcCommon }
|
362 |
|
363 |
function TIpcCommon.GetSa: PSecurityAttributes;
|
364 |
begin
|
365 |
Result := nil
|
366 |
end;
|
367 |
|
368 |
function TIpcCommon.sem_op(SemNum, op: integer; flags: cshort): cint;
|
369 |
var sembuf: TSEMbuf;
|
370 |
begin
|
371 |
sembuf.sem_num := SemNum;
|
372 |
sembuf.sem_op:= op;
|
373 |
sembuf.sem_flg := flags or SEM_UNDO;
|
374 |
Result := semop(FSemaphoreSetID,@sembuf,1);
|
375 |
end;
|
376 |
|
377 |
function TIpcCommon.sem_timedop(SemNum, op: integer; timeout_secs: integer;
|
378 |
flags: cshort): cint;
|
379 |
var sembuf: TSEMbuf;
|
380 |
timeout: TimeSpec;
|
381 |
begin
|
382 |
sembuf.sem_num := SemNum;
|
383 |
sembuf.sem_op:= op;
|
384 |
sembuf.sem_flg := flags or SEM_UNDO;
|
385 |
timeout.tv_sec := timeout_secs;
|
386 |
timeout.tv_nsec := 0;
|
387 |
{$IFDEF HAS_SEMTIMEDOP}
|
388 |
Result := semtimedop(FSemaphoreSetID,@sembuf,1,@timeout);
|
389 |
{$ELSE}
|
390 |
Result := semop(FSemaphoreSetID,@sembuf,1); {May hang on race condition}
|
391 |
{$ENDIF}
|
392 |
end;
|
393 |
|
394 |
function TIpcCommon.GetSemValue(SemNum: integer): cint;
|
395 |
var args :TSEMun;
|
396 |
begin
|
397 |
Result := semctl(FSemaphoreSetID,SemNum,SEM_GETVAL,args);
|
398 |
if Result < 0 then
|
399 |
IBError(ibxeSV5APIError,['GetSemValue: '+strError(GetLastErrno)]);
|
400 |
end;
|
401 |
|
402 |
procedure TIpcCommon.SemInit(SemNum, AValue: cint);
|
403 |
var args :TSEMun;
|
404 |
begin
|
405 |
//writeln('Initialising ',SemNum,' to ',AValue);
|
406 |
args.val := AValue;
|
407 |
if semctl(FSemaphoreSetID,SemNum,SEM_SETVAL,args) < 0 then
|
408 |
IBError(ibxeCannotCreateSharedResource,['Unable to initialise Semaphone ' +
|
409 |
IntToStr(SemNum) + '- ' + StrError(GetLastErrno)]);
|
410 |
|
411 |
end;
|
412 |
|
413 |
{ TMutex }
|
414 |
|
415 |
constructor TMutex.Create(SemNumber: cint);
|
416 |
begin
|
417 |
inherited Create;
|
418 |
FMutexSemaphore := SemNumber;
|
419 |
if FInitialiser then
|
420 |
SemInit(FMutexSemaphore,1)
|
421 |
end;
|
422 |
|
423 |
{ Obtain ownership of the Mutex and prevent other threads from accessing protected resource }
|
424 |
|
425 |
procedure TMutex.Lock;
|
426 |
begin
|
427 |
//writeln('Lock: Entering Mutex ',FMutexSemaphore,' LockCount=',FLockCount,' State = ',GetSemValue(FMutexSemaphore));
|
428 |
if FLockCount = 0 then
|
429 |
sem_op(FMutexSemaphore,-1);
|
430 |
Inc(FLockCount);
|
431 |
//writeln('Lock: Mutex Exit');
|
432 |
end;
|
433 |
|
434 |
{Give up ownership of the Mutex and allow other threads access }
|
435 |
|
436 |
procedure TMutex.Unlock;
|
437 |
begin
|
438 |
//writeln('UnLock: Entering Mutex, LockCount=',FLockCount);
|
439 |
if FLockCount = 0 then Exit;
|
440 |
Dec(FLockCount);
|
441 |
if FLockCount = 0 then
|
442 |
sem_op(FMutexSemaphore,1);
|
443 |
//writeln('UnLock: Mutex Exit',' State = ',GetSemValue(FMutexSemaphore));
|
444 |
end;
|
445 |
|
446 |
{ TSingleLockGate }
|
447 |
|
448 |
function TSingleLockGate.GetWaitingThreads: integer;
|
449 |
begin
|
450 |
Result := FWaitingThreads^
|
451 |
end;
|
452 |
|
453 |
constructor TSingleLockGate.Create(SemNum: cint; AOwner: TGlobalInterface);
|
454 |
begin
|
455 |
inherited Create;
|
456 |
FOwner := AOwner;
|
457 |
FSignalledState := PInteger(FOwner.SharedMemory.Allocate(sizeof(FSignalledState)));
|
458 |
FWaitingThreads := PInteger(FOwner.SharedMemory.Allocate(sizeof(FWaitingThreads)));
|
459 |
FSemaphore := SemNum;
|
460 |
FMutex := SemNum + 1;
|
461 |
if FInitialiser then
|
462 |
begin
|
463 |
FSignalledState^ := 1;
|
464 |
FWaitingThreads^ := 0;
|
465 |
SemInit(FSemaphore,0);
|
466 |
SemInit(FMutex,1);
|
467 |
end;
|
468 |
end;
|
469 |
|
470 |
procedure TSingleLockGate.PassthroughGate;
|
471 |
begin
|
472 |
if FSignalledState^ = 0 then
|
473 |
begin
|
474 |
sem_op(FMutex,-1,0); //Acquire Mutex
|
475 |
Inc(FWaitingThreads^);
|
476 |
sem_op(FMutex,1,0); //Release Mutex
|
477 |
//writeln(ClassName + ': Wait State Entered ',FSemaphore,' = ',GetSemValue(FSemaphore));
|
478 |
sem_op(FSemaphore,-1,0); //Enter Wait
|
479 |
//writeln(ClassName + ': Wait State Ends ',FSemaphore);
|
480 |
end;
|
481 |
end;
|
482 |
|
483 |
procedure TSingleLockGate.Unlock;
|
484 |
begin
|
485 |
if FSignalledState^ = 0 then
|
486 |
begin
|
487 |
FSignalledState^ := 1;
|
488 |
sem_op(FMutex,-1,0); //Acquire Mutex
|
489 |
//writeln(ClassName + ': Unlocking' ,FSemaphore);
|
490 |
sem_op(FSemaphore,FWaitingThreads^,0);
|
491 |
FWaitingThreads^ := 0;
|
492 |
sem_op(FMutex,1,0); //Release Mutex
|
493 |
end;
|
494 |
end;
|
495 |
|
496 |
procedure TSingleLockGate.Lock;
|
497 |
begin
|
498 |
if FSignalledState^ = 1 then
|
499 |
begin
|
500 |
//writeln(ClassName + ': Locking Gate ',FSemaphore);
|
501 |
SemInit(FSemaphore,0);
|
502 |
FSignalledState^ := 0;
|
503 |
end;
|
504 |
end;
|
505 |
|
506 |
{ TMultilockGate }
|
507 |
|
508 |
constructor TMultilockGate.Create(SemNum: cint; AOwner: TGlobalInterface);
|
509 |
begin
|
510 |
inherited Create;
|
511 |
FOwner := AOwner;
|
512 |
FSemaphore := SemNum;
|
513 |
FMutex := SemNum + 1;
|
514 |
FLockCount := PInteger(FOwner.SharedMemory.Allocate(sizeof(FLockCount)));
|
515 |
if FInitialiser then
|
516 |
begin
|
517 |
FLockCount^ := 0;
|
518 |
SemInit(FSemaphore,1);
|
519 |
SemInit(FMutex,1);
|
520 |
end;
|
521 |
end;
|
522 |
|
523 |
function TMultilockGate.GetLockCount: integer;
|
524 |
begin
|
525 |
Result := FLockCount^
|
526 |
end;
|
527 |
|
528 |
procedure TMultilockGate.Lock;
|
529 |
begin
|
530 |
sem_op(FMutex,-1,0); //Acquire Mutex
|
531 |
if FLockCount^ = 0 then
|
532 |
begin
|
533 |
//writeln(ClassName,': Locking ',FSemaphore);
|
534 |
SemInit(FSemaphore,0);
|
535 |
end;
|
536 |
Inc(FLockCount^);
|
537 |
sem_op(FMutex,1,0); //Release Mutex
|
538 |
end;
|
539 |
|
540 |
procedure TMultilockGate.Unlock;
|
541 |
begin
|
542 |
sem_op(FMutex,-1,0); //Acquire Mutex
|
543 |
Dec(FLockCount^);
|
544 |
if FLockCount^ <= 0 then
|
545 |
begin
|
546 |
//writeln(ClassName,': UnLocking ',FSemaphore);
|
547 |
SemInit(FSemaphore,1);
|
548 |
FLockCount^ := 0
|
549 |
end;
|
550 |
sem_op(FMutex,1,0); //Release Mutex
|
551 |
end;
|
552 |
|
553 |
procedure TMultilockGate.PassthroughGate;
|
554 |
begin
|
555 |
if FLockCount^ = 0 then
|
556 |
Exit;
|
557 |
//writeln(ClassName,': Waiting on ',FSemaphore);
|
558 |
while sem_timedop(FSemaphore,-1,cDefaultTimeout) < 0 do
|
559 |
{looks like we lost a reader}
|
560 |
begin
|
561 |
if FLockCount^ > 0 then
|
562 |
begin
|
563 |
UnLock;
|
564 |
if assigned(FOnGateTimeout) then
|
565 |
OnGateTimeout(self)
|
566 |
end
|
567 |
end;
|
568 |
sem_op(FSemaphore,1);
|
569 |
//writeln(ClassName,': Wait done on ',FSemaphore);
|
570 |
end;
|
571 |
|
572 |
|
573 |
{ TGlobalInterface }
|
574 |
|
575 |
function TGlobalInterface.GetMonitorCount: integer;
|
576 |
begin
|
577 |
Result := GetSemValue(cMonitorCounter)
|
578 |
end;
|
579 |
|
580 |
constructor TGlobalInterface.Create;
|
581 |
begin
|
582 |
inherited Create;
|
583 |
FSharedMemory := TSharedMemory.Create(cMonitorHookSize);
|
584 |
|
585 |
FWriteLock := TMutex.Create(cMutexSemaphore);
|
586 |
|
587 |
FDataAvailableEvent := TSingleLockGate.Create(cDataAvailableEventSemaphore,self);
|
588 |
FWriterBusyEvent := TSingleLockGate.Create(cWriterBusyEventSemaphore,self);
|
589 |
FReadReadyEvent := TMultiLockGate.Create(cReadReadyEventSemaphore,self);
|
590 |
FReadFinishedEvent := TMultiLockGate.Create(cReadFinishedEventSemaphore,self);
|
591 |
|
592 |
if FInitialiser then
|
593 |
SemInit(cMonitorCounter,0);
|
594 |
FTraceDataType := PInteger(FSharedMemory.Allocate(sizeof(Integer)));
|
595 |
FTimeStamp := PDateTime(FSharedMemory.Allocate(sizeof(TDateTime)));
|
596 |
FBufferSize := PInteger(FSharedMemory.Allocate(sizeof(Integer)));
|
597 |
FBuffer := FSharedMemory.Allocate(0); //All remaining
|
598 |
FMaxBufferSize := FSharedMemory.LastAllocationSize;
|
599 |
|
600 |
if FInitialiser then
|
601 |
begin
|
602 |
FBufferSize^ := 0;
|
603 |
FDataAvailableEvent.Lock
|
604 |
end;
|
605 |
end;
|
606 |
|
607 |
destructor TGlobalInterface.Destroy;
|
608 |
begin
|
609 |
if assigned(FWriteLock) then FWriteLock.Free;
|
610 |
if assigned(FDataAvailableEvent) then FDataAvailableEvent.Free;
|
611 |
if assigned(FWriterBusyEvent) then FWriterBusyEvent.Free;
|
612 |
if assigned(FReadReadyEvent) then FReadReadyEvent.Free;
|
613 |
if assigned(FReadFinishedEvent) then FReadFinishedEvent.Free;
|
614 |
if assigned(FSharedMemory) then FSharedMemory.Free;
|
615 |
inherited Destroy;
|
616 |
end;
|
617 |
|
618 |
procedure TGlobalInterface.IncMonitorCount;
|
619 |
begin
|
620 |
sem_op(cMonitorCounter,1);
|
621 |
end;
|
622 |
|
623 |
procedure TGlobalInterface.DecMonitorCount;
|
624 |
begin
|
625 |
sem_op(cMonitorCounter,-1,IPC_NOWAIT);
|
626 |
end;
|
627 |
|
628 |
procedure TGlobalInterface.SendTrace(TraceObject: TTraceObject);
|
629 |
begin
|
630 |
FTraceDataType^ := Integer(TraceObject.FDataType);
|
631 |
FTimeStamp^ := TraceObject.FTimeStamp;
|
632 |
FBufferSize^ := Min(Length(TraceObject.FMsg), MaxBufferSize);
|
633 |
Move(TraceObject.FMsg[1], FBuffer^, FBufferSize^);
|
634 |
end;
|
635 |
|
636 |
procedure TGlobalInterface.ReceiveTrace(TraceObject: TTraceObject);
|
637 |
begin
|
638 |
SetString(TraceObject.FMsg, FBuffer, FBufferSize^);
|
639 |
TraceObject.FDataType := TTraceFlag(FTraceDataType^);
|
640 |
TraceObject.FTimeStamp := TDateTime(FTimeStamp^);
|
641 |
end;
|
642 |
|
643 |
|
644 |
|