250 lines
4.2 KiB
C
250 lines
4.2 KiB
C
/*++
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Copyright (c) 1998 Microsoft Corporation
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Module Name:
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tracelog.c
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Abstract:
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This module implements a trace log.
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A trace log is a fast, in-memory, thread safe activity log useful
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for debugging certain classes of problems. They are especially useful
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when debugging reference count bugs.
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Author:
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Keith Moore (keithmo) 30-Apr-1997
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Revision History:
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--*/
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#include "spudp.h"
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//
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// Private contants.
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//
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#define ALLOC_MEM(cb) \
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SPUD_ALLOCATE_POOL( \
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NonPagedPool, \
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(ULONG)(cb), \
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SPUD_TRACE_LOG_POOL_TAG \
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)
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#define FREE_MEM(ptr) \
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SPUD_FREE_POOL( \
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(PVOID)(ptr) \
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)
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#define DBG_ASSERT ASSERT
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#if 0
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NOT PAGEABLE -- CreateTraceLog
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NOT PAGEABLE -- DestroyTraceLog
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NOT PAGEABLE -- WriteTraceLog
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NOT PAGEABLE -- ResetTraceLog
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#endif
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//
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// Public functions.
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//
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PTRACE_LOG
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CreateTraceLog(
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IN LONG LogSize,
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IN LONG ExtraBytesInHeader,
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IN LONG EntrySize
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)
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/*++
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Routine Description:
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Creates a new (empty) trace log buffer.
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Arguments:
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LogSize - The number of entries in the log.
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ExtraBytesInHeader - The number of extra bytes to include in the
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log header. This is useful for adding application-specific
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data to the log.
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EntrySize - The size (in bytes) of each entry.
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Return Value:
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PTRACE_LOG - Pointer to the newly created log if successful,
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NULL otherwise.
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--*/
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{
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LONG totalSize;
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PTRACE_LOG log;
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//
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// Sanity check the parameters.
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//
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DBG_ASSERT( LogSize > 0 );
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DBG_ASSERT( EntrySize > 0 );
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DBG_ASSERT( ( EntrySize & 3 ) == 0 );
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//
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// Allocate & initialize the log structure.
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//
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totalSize = sizeof(*log) + ( LogSize * EntrySize ) + ExtraBytesInHeader;
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DBG_ASSERT( totalSize > 0 );
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log = (PTRACE_LOG)ALLOC_MEM( totalSize );
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//
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// Initialize it.
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//
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if( log != NULL ) {
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RtlZeroMemory( log, totalSize );
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log->Signature = TRACE_LOG_SIGNATURE;
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log->LogSize = LogSize;
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log->NextEntry = -1;
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log->EntrySize = EntrySize;
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log->LogBuffer = (PUCHAR)( log + 1 ) + ExtraBytesInHeader;
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}
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return log;
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} // CreateTraceLog
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VOID
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DestroyTraceLog(
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IN PTRACE_LOG Log
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)
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/*++
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Routine Description:
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Destroys a trace log buffer created with CreateTraceLog().
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Arguments:
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Log - The trace log buffer to destroy.
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Return Value:
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None.
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--*/
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{
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DBG_ASSERT( Log != NULL );
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DBG_ASSERT( Log->Signature == TRACE_LOG_SIGNATURE );
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Log->Signature = TRACE_LOG_SIGNATURE_X;
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FREE_MEM( Log );
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} // DestroyTraceLog
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VOID
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WriteTraceLog(
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IN PTRACE_LOG Log,
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IN PVOID Entry
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)
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/*++
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Routine Description:
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Writes a new entry to the specified trace log.
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Arguments:
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Log - The log to write to.
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Entry - Pointer to the data to write. This buffer is assumed to be
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Log->EntrySize bytes long.
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Return Value:
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None
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--*/
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{
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PUCHAR target;
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LONG index;
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DBG_ASSERT( Log != NULL );
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DBG_ASSERT( Log->Signature == TRACE_LOG_SIGNATURE );
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DBG_ASSERT( Entry != NULL );
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//
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// Find the next slot, copy the entry to the slot.
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//
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index = InterlockedIncrement( &Log->NextEntry ) % Log->LogSize;
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target = Log->LogBuffer + ( index * Log->EntrySize );
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RtlCopyMemory(
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target,
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Entry,
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Log->EntrySize
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);
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} // WriteTraceLog
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VOID
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ResetTraceLog(
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IN PTRACE_LOG Log
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)
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/*++
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Routine Description:
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Resets the specified trace log.
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Arguments:
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Log - The log to reset.
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Return Value:
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None
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--*/
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{
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DBG_ASSERT( Log != NULL );
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DBG_ASSERT( Log->Signature == TRACE_LOG_SIGNATURE );
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RtlZeroMemory(
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( Log + 1 ),
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Log->LogSize * Log->EntrySize
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);
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Log->NextEntry = -1;
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} // ResetTraceLog
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