windows-xp/Source/XPSP1/NT/base/ntos/rtl/eballoc.c

/*++

Copyright (c) 1990  Microsoft Corporation

Module Name:

    eballoc.c

Abstract:

    Process/Thread Environment Block allocation functions

Author:

    Steve Wood (stevewo) 10-May-1990

Revision History:

--*/

#include "ntrtlp.h"
#include <nturtl.h>

#if defined(ALLOC_PRAGMA) && defined(NTOS_KERNEL_RUNTIME)
#pragma alloc_text(PAGE,RtlAcquirePebLock)
#pragma alloc_text(PAGE,RtlReleasePebLock)
#endif

typedef VOID (*PEB_LOCK_ROUTINE)(PVOID FastLock);

VOID
RtlAcquirePebLock( VOID )
{
    PEB_LOCK_ROUTINE LockRoutine;
    PPEB Peb;
    LARGE_INTEGER Timeout;

    RTL_PAGED_CODE();

    Peb = NtCurrentPeb();

    LockRoutine = (PEB_LOCK_ROUTINE)Peb->FastPebLockRoutine;
    ASSERT(LockRoutine);

    for (;;) {
        try {
            (LockRoutine)(Peb->FastPebLock);
	    break;
        } except ( GetExceptionCode() == STATUS_INSUFFICIENT_RESOURCES 
                   ? EXCEPTION_EXECUTE_HANDLER
                   : EXCEPTION_CONTINUE_SEARCH ) {
            //
            // Unfortunately, a number of things assume that
            // RtlAcquirePebLock can't fail.  So we need to loop and
            // try again.
            //
            Timeout.QuadPart = UInt32x32To64( 10 /* Milliseconds to sleep */,
                                              10000 /* Milliseconds to 100 Nanoseconds) */);
            Timeout.QuadPart *= -1; /* Make it a relative time */
            NtDelayExecution(FALSE, &Timeout);
            continue;
        }
    }
}

VOID
RtlReleasePebLock( VOID )
{
    PEB_LOCK_ROUTINE LockRoutine;
    PPEB Peb;

    RTL_PAGED_CODE();

    Peb = NtCurrentPeb();

    LockRoutine = (PEB_LOCK_ROUTINE)Peb->FastPebUnlockRoutine;
    ASSERT(LockRoutine);
    (LockRoutine)(Peb->FastPebLock);
}