Leaked source code of windows server 2003
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//=======================================================================
//
// Copyright (c) 1998-2001 Microsoft Corporation. All Rights Reserved.
//
// File: FreeLog.cpp
//
// Owner: KenSh
//
// Description:
//
// Runtime logging for use in both checked and free builds.
//
//=======================================================================
#include <windows.h>
#include <tchar.h>
#include <stdio.h>
#include <malloc.h>
#include "FreeLog.h"
#include <MISTSAFE.h>
#ifndef _countof
#define _countof(ar) (sizeof(ar)/sizeof((ar)[0]))
#endif
// Unicode files start with the 2 bytes { FF FE }.
// This is the little-endian version of those 2 bytes.
#define UNICODE_FILE_HEADER 0xFEFF
#define MUTEX_TIMEOUT 1000 // Don't wait more than 1 second to write to logfile
#define MAX_MUTEX_WAITS 4 // Don't keep trying after this many failures
#define LOG_FILE_BIG_SIZE 50000 // Don't bother trimming if file is smaller than this
#define LOG_LINES_TRIM_FROM 1000 // Start trimming if more than this many lines
#define LOG_LINES_TRIM_TO 750 // Trim til the log file is this many lines
#define LOG_LEVEL_SUCCESS 0
#define LOG_LEVEL_FAILURE 1
#define MAX_MSG_LENGTH (MAX_PATH + 20)
#define MAX_ERROR_LENGTH 128
static const TCHAR c_szUnknownModuleName[] = _T("?");
// Local functions
void LogMessageExV(UINT nLevel, DWORD dwError, LPCSTR pszFormatA, va_list args);
//============================================================================
//
// Private CFreeLogging class to keep track of log file resources
//
//============================================================================
class CFreeLogging
{
public:
CFreeLogging(LPCTSTR pszModuleName, LPCTSTR pszLogFileName);
~CFreeLogging();
void WriteLine(LPCTSTR pszText, UINT nLevel, DWORD dwError);
private:
inline static HANDLE CreateMutex(LPCTSTR pszMutexName);
inline HANDLE OpenLogFile(LPCTSTR pszFileName);
inline void CloseLogFile();
void TrimLogFile();
BOOL AcquireMutex();
void ReleaseMutex();
private:
HANDLE m_hFile;
HANDLE m_hMutex;
int m_cLinesWritten;
int m_cFailedWaits;
LPTSTR m_pszModuleName;
};
CFreeLogging* g_pFreeLogging;
//============================================================================
//
// Public functions
//
//============================================================================
void InitFreeLogging(LPCTSTR pszModuleName, LPCTSTR pszLogFileName)
{
if (g_pFreeLogging == NULL)
{
g_pFreeLogging = new CFreeLogging(pszModuleName, pszLogFileName);
}
}
void TermFreeLogging()
{
delete g_pFreeLogging;
g_pFreeLogging = NULL;
}
void LogMessage(LPCSTR pszFormatA, ...)
{
va_list arglist;
va_start(arglist, pszFormatA);
LogMessageExV(LOG_LEVEL_SUCCESS, 0, pszFormatA, arglist);
va_end(arglist);
}
void LogError(DWORD dwError, LPCSTR pszFormatA, ...)
{
va_list arglist;
va_start(arglist, pszFormatA);
LogMessageExV(LOG_LEVEL_FAILURE, dwError, pszFormatA, arglist);
va_end(arglist);
}
void LogMessageExV(UINT nLevel, DWORD dwError, LPCSTR pszFormatA, va_list args)
{
if (g_pFreeLogging != NULL)
{
char szBufA[MAX_MSG_LENGTH];
size_t nRem=0;
StringCchVPrintfExA(szBufA, _countof(szBufA), NULL, &nRem, MISTSAFE_STRING_FLAGS, pszFormatA, args);
int cchA = _countof(szBufA) - nRem;
#ifdef UNICODE
WCHAR szBufW[MAX_MSG_LENGTH];
MultiByteToWideChar(CP_ACP, 0, szBufA, cchA+1, szBufW, _countof(szBufW));
g_pFreeLogging->WriteLine(szBufW, nLevel, dwError);
#else
g_pFreeLogging->WriteLine(szBufA, nLevel, dwError);
#endif
}
}
//============================================================================
//
// CFreeLogging implementation
//
//============================================================================
CFreeLogging::CFreeLogging(LPCTSTR pszModuleName, LPCTSTR pszLogFileName)
: m_cFailedWaits(0),
m_cLinesWritten(0)
{
m_pszModuleName = _tcsdup(pszModuleName);
if (m_pszModuleName == NULL)
m_pszModuleName = (LPTSTR)c_szUnknownModuleName;
m_hMutex = CreateMutex(pszLogFileName);
m_hFile = OpenLogFile(pszLogFileName);
}
CFreeLogging::~CFreeLogging()
{
CloseLogFile();
if (m_hMutex != NULL)
CloseHandle(m_hMutex);
if (m_pszModuleName != c_szUnknownModuleName)
free(m_pszModuleName);
}
inline HANDLE CFreeLogging::CreateMutex(LPCTSTR pszMutexName)
{
// Create a mutex in the global namespace (works across TS sessions)
HANDLE hMutex = ::CreateMutex(NULL, FALSE, pszMutexName);
return hMutex;
}
inline HANDLE CFreeLogging::OpenLogFile(LPCTSTR pszLogFileName)
{
HANDLE hFile = INVALID_HANDLE_VALUE;
TCHAR szPath[MAX_PATH+1];
int cch = GetWindowsDirectory(szPath, _countof(szPath)-1);
if(cch >0)
{
if (szPath[cch-1] != _T('\\'))
szPath[cch++] = _T('\\');
HRESULT hr = StringCchCopyEx(szPath + cch, _countof(szPath)-cch, pszLogFileName, NULL, NULL, MISTSAFE_STRING_FLAGS);
if(FAILED(hr))
return hFile;
hFile = CreateFile(szPath, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
}
#ifdef UNICODE
if (hFile != INVALID_HANDLE_VALUE)
{
if (AcquireMutex())
{
//
// Check for the unicode header { FF FE }
//
WORD wHeader = 0;
DWORD cbRead;
(void)ReadFile(hFile, &wHeader, sizeof(wHeader), &cbRead, NULL);
//
// Write the header if there isn't one. This may be due to the
// file being newly created, or to an ANSI-formatted file.
//
if (wHeader != UNICODE_FILE_HEADER)
{
SetFilePointer(hFile, 0, NULL, FILE_BEGIN);
DWORD cbWritten;
wHeader = UNICODE_FILE_HEADER;
WriteFile(hFile, &wHeader, sizeof(wHeader), &cbWritten, NULL);
SetEndOfFile(hFile);
}
ReleaseMutex();
}
}
#endif
return hFile;
}
inline void CFreeLogging::CloseLogFile()
{
if (m_hFile != INVALID_HANDLE_VALUE)
{
// Trim old stuff from the log before closing the file
TrimLogFile();
CloseHandle(m_hFile);
m_hFile = INVALID_HANDLE_VALUE;
}
}
BOOL CFreeLogging::AcquireMutex()
{
// In rare case where mutex not created, we allow file operations
// with no synchronization
if (m_hMutex == NULL)
return TRUE;
// Don't keep waiting if we've been blocked in the past
if (m_cFailedWaits >= MAX_MUTEX_WAITS)
return FALSE;
BOOL fResult = TRUE;
if (WaitForSingleObject(m_hMutex, MUTEX_TIMEOUT) != WAIT_OBJECT_0)
{
fResult = FALSE;
m_cFailedWaits++;
}
return fResult;
}
void CFreeLogging::ReleaseMutex()
{
if (m_hMutex != NULL) // Note: AcquireMutex succeeds even if m_hMutex is NULL
{
::ReleaseMutex(m_hMutex);
}
}
void CFreeLogging::WriteLine(LPCTSTR pszText, UINT nLevel, DWORD dwError)
{
if (m_hFile != INVALID_HANDLE_VALUE)
{
DWORD cbText = lstrlen(pszText) * sizeof(TCHAR);
if (AcquireMutex())
{
DWORD cbWritten;
SetFilePointer(m_hFile, 0, NULL, FILE_END);
//
// Write time/date/module as a prefix
//
// 2001-05-03 13:49:01 21:49:01 CDM Failed Loading module (Error 0x00000005: Access is denied.)
//
// NOTE: ISO 8601 format for date/time. Local time first, then GMT.
//
TCHAR szPrefix[60];
SYSTEMTIME sysTime, gmtTime;
GetLocalTime(&sysTime);
GetSystemTime(&gmtTime);
LPCTSTR pszStatus = (nLevel == LOG_LEVEL_SUCCESS) ? _T("Success") : _T("Error ");
StringCchPrintfEx(szPrefix, _countof(szPrefix), NULL, NULL, MISTSAFE_STRING_FLAGS,
_T("%04d-%02d-%02d %02d:%02d:%02d %02d:%02d:%02d %s %-13s "),
sysTime.wYear, sysTime.wMonth, sysTime.wDay,
sysTime.wHour, sysTime.wMinute, sysTime.wSecond,
gmtTime.wHour, gmtTime.wMinute, gmtTime.wSecond,
pszStatus, m_pszModuleName);
WriteFile(m_hFile, szPrefix, lstrlen(szPrefix) * sizeof(TCHAR), &cbWritten, NULL);
//
// Write the message followed by error info (if any) and a newline
//
WriteFile(m_hFile, pszText, cbText, &cbWritten, NULL);
if (nLevel != LOG_LEVEL_SUCCESS)
{
TCHAR szError[MAX_ERROR_LENGTH];
HRESULT hr=S_OK;
size_t nRem=0;
// nRem contains the remaining characters in the buffer including the null terminator
// To get the number of characters written in to the buffer we use
// int cchErrorPrefix = _countof(szError) - nRem;
StringCchPrintfEx(szError, _countof(szError), NULL, &nRem, MISTSAFE_STRING_FLAGS, _T(" (Error 0x%08X: "), dwError);
// Get the number of characters written in to the buffer
int cchErrorPrefix = _countof(szError) - nRem;
int cchErrorText = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, dwError, 0,
szError + cchErrorPrefix, _countof(szError) - cchErrorPrefix - 1, NULL);
int cchError = cchErrorPrefix + cchErrorText;
cchError -= 2; // backup past ": " or "\r\n"
StringCchCopyEx(szError + cchError, _countof(szError)-cchError, _T(")"), NULL, NULL, MISTSAFE_STRING_FLAGS);
WriteFile(m_hFile, szError, (cchError + 1) * sizeof(TCHAR), &cbWritten, NULL);
}
WriteFile(m_hFile, _T("\r\n"), 2 * sizeof(TCHAR), &cbWritten, NULL);
//
// If we've written a ton of stuff, trim now rather than waiting
// for the module to unload. (This check is only for how much this
// module has written, not how big the log file itself is.)
//
if (++m_cLinesWritten > LOG_LINES_TRIM_FROM)
{
TrimLogFile();
m_cLinesWritten = LOG_LINES_TRIM_TO;
}
ReleaseMutex();
}
}
}
// Checks the size of the log file, and trims it if necessary.
void CFreeLogging::TrimLogFile()
{
if (AcquireMutex())
{
DWORD cbFile = GetFileSize(m_hFile, NULL);
if (cbFile > LOG_FILE_BIG_SIZE)
{
DWORD cbFileNew = cbFile;
//
// Create a memory-mapped file so we can use memmove
//
HANDLE hMapping = CreateFileMapping(m_hFile, NULL, PAGE_READWRITE, 0, 0, NULL);
if (hMapping != NULL)
{
LPTSTR pszFileStart = (LPTSTR)MapViewOfFile(hMapping, FILE_MAP_WRITE, 0, 0, 0);
if (pszFileStart != NULL)
{
LPTSTR pszEnd = (LPTSTR)((LPBYTE)pszFileStart + cbFile);
LPTSTR pszTextStart = pszFileStart;
#ifdef UNICODE
pszTextStart++; // skip the 2-byte header
#endif
//
// Count newlines
//
int cLines = 0;
for (LPTSTR pch = pszTextStart; pch < pszEnd; )
{
if (*pch == _T('\n'))
cLines++;
// REVIEW: in Ansi builds should we call CharNextExA?
// If so, what code page is the log file in?
pch++;
}
if (cLines > LOG_LINES_TRIM_FROM)
{
int cTrimLines = cLines - LOG_LINES_TRIM_TO;
for (pch = pszTextStart; pch < pszEnd; )
{
if (*pch == _T('\n'))
cTrimLines--;
// REVIEW: in Ansi builds should we call CharNextExA?
// If so, what code page is the log file in?
pch++;
if (cTrimLines <= 0)
break;
}
// Move more recent data to beginning of file
int cchMove = (int)(pszEnd - pch);
memmove(pszTextStart, pch, cchMove * sizeof(TCHAR));
cbFileNew = (cchMove * sizeof(TCHAR));
#ifdef UNICODE
cbFileNew += sizeof(WORD);
#endif
}
UnmapViewOfFile(pszFileStart);
}
CloseHandle(hMapping);
if (cbFileNew != cbFile)
{
// Truncate the file, now that we've moved data as needed
SetFilePointer(m_hFile, cbFileNew, NULL, FILE_BEGIN);
SetEndOfFile(m_hFile);
}
}
}
ReleaseMutex();
}
}