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Reactos
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327/* * COPYRIGHT: See COPYING in the top level directory * PROJECT: ReactOS system libraries * FILE: lib/rtl/resource.c * PURPOSE: Resource (multiple-reader-single-writer lock) functions * PROGRAMMER: Partially takem from Wine: * Copyright 1996-1998 Marcus Meissner * 1999 Alex Korobka */
/* INCLUDES *****************************************************************/
#include <rtl.h>
#define NDEBUG#include <debug.h>
/* FUNCTIONS ***************************************************************/
/* * @implemented */VOIDNTAPIRtlInitializeResource(PRTL_RESOURCE Resource){ NTSTATUS Status;
Status = RtlInitializeCriticalSection(&Resource->Lock); if (!NT_SUCCESS(Status)) { RtlRaiseStatus(Status); }
Status = NtCreateSemaphore(&Resource->SharedSemaphore, SEMAPHORE_ALL_ACCESS, NULL, 0, 65535); if (!NT_SUCCESS(Status)) { RtlRaiseStatus(Status); } Resource->SharedWaiters = 0;
Status = NtCreateSemaphore(&Resource->ExclusiveSemaphore, SEMAPHORE_ALL_ACCESS, NULL, 0, 65535); if (!NT_SUCCESS(Status)) { RtlRaiseStatus(Status); }
Resource->ExclusiveWaiters = 0; Resource->NumberActive = 0; Resource->OwningThread = NULL; Resource->TimeoutBoost = 0; /* no info on this one, default value is 0 */}
/* * @implemented */VOIDNTAPIRtlDeleteResource(PRTL_RESOURCE Resource){ RtlDeleteCriticalSection(&Resource->Lock); NtClose(Resource->ExclusiveSemaphore); NtClose(Resource->SharedSemaphore); Resource->OwningThread = NULL; Resource->ExclusiveWaiters = 0; Resource->SharedWaiters = 0; Resource->NumberActive = 0;}
/* * @implemented */BOOLEANNTAPIRtlAcquireResourceExclusive( PRTL_RESOURCE Resource, BOOLEAN Wait){ NTSTATUS Status; BOOLEAN retVal = FALSE;
start: RtlEnterCriticalSection(&Resource->Lock); if (Resource->NumberActive == 0) /* lock is free */ { Resource->NumberActive = -1; retVal = TRUE; } else if (Resource->NumberActive < 0) /* exclusive lock in progress */ { if (Resource->OwningThread == NtCurrentTeb()->ClientId.UniqueThread) { retVal = TRUE; Resource->NumberActive--; goto done; }wait: if (Wait) { Resource->ExclusiveWaiters++;
RtlLeaveCriticalSection(&Resource->Lock); Status = NtWaitForSingleObject(Resource->ExclusiveSemaphore, FALSE, NULL); if (!NT_SUCCESS(Status)) goto done; goto start; /* restart the acquisition to avoid deadlocks */ } } else /* one or more shared locks are in progress */ { if (Wait) goto wait; } if (retVal) Resource->OwningThread = NtCurrentTeb()->ClientId.UniqueThread;done: RtlLeaveCriticalSection(&Resource->Lock); return retVal;}
/* * @implemented */BOOLEANNTAPIRtlAcquireResourceShared( PRTL_RESOURCE Resource, BOOLEAN Wait){ NTSTATUS Status = STATUS_UNSUCCESSFUL; BOOLEAN retVal = FALSE;
start: RtlEnterCriticalSection(&Resource->Lock); if (Resource->NumberActive < 0) { if (Resource->OwningThread == NtCurrentTeb()->ClientId.UniqueThread) { Resource->NumberActive--; retVal = TRUE; goto done; }
if (Wait) { Resource->SharedWaiters++; RtlLeaveCriticalSection(&Resource->Lock); Status = NtWaitForSingleObject(Resource->SharedSemaphore, FALSE, NULL); if (!NT_SUCCESS(Status)) goto done; goto start; } } else { if (Status != STATUS_WAIT_0) /* otherwise RtlReleaseResource() has already done it */ Resource->NumberActive++; retVal = TRUE; }done: RtlLeaveCriticalSection(&Resource->Lock); return retVal;}
/* * @implemented */VOIDNTAPIRtlConvertExclusiveToShared(PRTL_RESOURCE Resource){ RtlEnterCriticalSection(&Resource->Lock);
if (Resource->NumberActive == -1) { Resource->OwningThread = NULL;
if (Resource->SharedWaiters > 0) { ULONG n; /* prevent new writers from joining until * all queued readers have done their thing */ n = Resource->SharedWaiters; Resource->NumberActive = Resource->SharedWaiters + 1; Resource->SharedWaiters = 0; NtReleaseSemaphore(Resource->SharedSemaphore, n, NULL); } else { Resource->NumberActive = 1; } }
RtlLeaveCriticalSection(&Resource->Lock);}
/* * @implemented */VOIDNTAPIRtlConvertSharedToExclusive(PRTL_RESOURCE Resource){ NTSTATUS Status;
RtlEnterCriticalSection(&Resource->Lock);
if (Resource->NumberActive == 1) { Resource->OwningThread = NtCurrentTeb()->ClientId.UniqueThread; Resource->NumberActive = -1; } else { Resource->ExclusiveWaiters++;
RtlLeaveCriticalSection(&Resource->Lock); Status = NtWaitForSingleObject(Resource->ExclusiveSemaphore, FALSE, NULL); if (!NT_SUCCESS(Status)) return;
RtlEnterCriticalSection(&Resource->Lock); Resource->OwningThread = NtCurrentTeb()->ClientId.UniqueThread; Resource->NumberActive = -1; } RtlLeaveCriticalSection(&Resource->Lock);}
/* * @implemented */VOIDNTAPIRtlReleaseResource(PRTL_RESOURCE Resource){ RtlEnterCriticalSection(&Resource->Lock);
if (Resource->NumberActive > 0) /* have one or more readers */ { Resource->NumberActive--; if (Resource->NumberActive == 0) { if (Resource->ExclusiveWaiters > 0) {wake_exclusive: Resource->ExclusiveWaiters--; NtReleaseSemaphore(Resource->ExclusiveSemaphore, 1, NULL); } } } else if (Resource->NumberActive < 0) /* have a writer, possibly recursive */ { Resource->NumberActive++; if (Resource->NumberActive == 0) { Resource->OwningThread = 0; if (Resource->ExclusiveWaiters > 0) { goto wake_exclusive; } else { if (Resource->SharedWaiters > 0) { ULONG n; /* prevent new writers from joining until * all queued readers have done their thing */ n = Resource->SharedWaiters; Resource->NumberActive = Resource->SharedWaiters; Resource->SharedWaiters = 0; NtReleaseSemaphore(Resource->SharedSemaphore, n, NULL); } } } } RtlLeaveCriticalSection(&Resource->Lock);}
/* * @implemented */VOIDNTAPIRtlDumpResource(PRTL_RESOURCE Resource){ DbgPrint("RtlDumpResource(%p):\n\tactive count = %d\n\twaiting readers = %u\n\twaiting writers = %u\n", Resource, Resource->NumberActive, Resource->SharedWaiters, Resource->ExclusiveWaiters);
if (Resource->NumberActive != 0) { DbgPrint("\towner thread = %p\n", Resource->OwningThread); }}
/* EOF */