memwatch.c

/*
** MEMWATCH.C
** Nonintrusive ANSI C memory leak / overwrite detection
** Copyright (C) 1992-2003 Johan Lindh
** All rights reserved.
** Version 2.71

   This file is part of MEMWATCH.

    MEMWATCH is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    MEMWATCH is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with MEMWATCH; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

**
** 920810 JLI   [1.00]
** 920830 JLI   [1.10 double-free detection]
** 920912 JLI   [1.15 mwPuts, mwGrab/Drop, mwLimit]
** 921022 JLI   [1.20 ASSERT and VERIFY]
** 921105 JLI   [1.30 C++ support and TRACE]
** 921116 JLI   [1.40 mwSetOutFunc]
** 930215 JLI   [1.50 modified ASSERT/VERIFY]
** 930327 JLI   [1.51 better auto-init & PC-lint support]
** 930506 JLI   [1.55 MemWatch class, improved C++ support]
** 930507 JLI   [1.60 mwTest & CHECK()]
** 930809 JLI   [1.65 Abort/Retry/Ignore]
** 930820 JLI   [1.70 data dump when unfreed]
** 931016 JLI   [1.72 modified C++ new/delete handling]
** 931108 JLI   [1.77 mwSetAssertAction() & some small changes]
** 940110 JLI   [1.80 no-mans-land alloc/checking]
** 940328 JLI   [2.00 version 2.0 rewrite]
**              Improved NML (no-mans-land) support.
**              Improved performance (especially for free()ing!).
**              Support for 'read-only' buffers (checksums)
**              ^^ NOTE: I never did this... maybe I should?
**              FBI (free'd block info) tagged before freed blocks
**              Exporting of the mwCounter variable
**              mwBreakOut() localizes debugger support
**              Allocation statistics (global, per-module, per-line)
**              Self-repair ability with relinking
** 950913 JLI   [2.10 improved garbage handling]
** 951201 JLI   [2.11 improved auto-free in emergencies]
** 960125 JLI   [X.01 implemented auto-checking using mwAutoCheck()]
** 960514 JLI   [2.12 undefining of existing macros]
** 960515 JLI   [2.13 possibility to use default new() & delete()]
** 960516 JLI   [2.20 suppression of file flushing on unfreed msgs]
** 960516 JLI   [2.21 better support for using MEMWATCH with DLL's]
** 960710 JLI   [X.02 multiple logs and mwFlushNow()]
** 960801 JLI   [2.22 merged X.01 version with current]
** 960805 JLI   [2.30 mwIsXXXXAddr() to avoid unneeded GP's]
** 960805 JLI   [2.31 merged X.02 version with current]
** 961002 JLI   [2.32 support for realloc() + fixed STDERR bug]
** 961222 JLI   [2.40 added mwMark() & mwUnmark()]
** 970101 JLI   [2.41 added over/underflow checking after failed ASSERT/VERIFY]
** 970113 JLI   [2.42 added support for PC-Lint 7.00g]
** 970207 JLI   [2.43 added support for strdup()]
** 970209 JLI   [2.44 changed default filename to lowercase]
** 970405 JLI   [2.45 fixed bug related with atexit() and some C++ compilers]
** 970723 JLI   [2.46 added MW_ARI_NULLREAD flag]
** 970813 JLI   [2.47 stabilized marker handling]
** 980317 JLI   [2.48 ripped out C++ support; wasn't working good anyway]
** 980318 JLI   [2.50 improved self-repair facilities & SIGSEGV support]
** 980417 JLI  [2.51 more checks for invalid addresses]
** 980512 JLI  [2.52 moved MW_ARI_NULLREAD to occur before aborting]
** 990112 JLI  [2.53 added check for empty heap to mwIsOwned]
** 990217 JLI  [2.55 improved the emergency repairs diagnostics and NML]
** 990224 JLI  [2.56 changed ordering of members in structures]
** 990303 JLI  [2.57 first maybe-fixit-for-hpux test]
** 990516 JLI  [2.58 added 'static' to the definition of mwAutoInit]
** 990517 JLI  [2.59 fixed some high-sensitivity warnings]
** 990610 JLI  [2.60 fixed some more high-sensitivity warnings]
** 990715 JLI  [2.61 changed TRACE/ASSERT/VERIFY macro names]
** 991001 JLI  [2.62 added CHECK_BUFFER() and mwTestBuffer()]
** 991007 JLI  [2.63 first shot at a 64-bit compatible version]
** 991009 JLI  [2.64 undef's strdup() if defined, mwStrdup made const]
** 000704 JLI  [2.65 added some more detection for 64-bits]
** 010502 JLI   [2.66 incorporated some user fixes]
**              [mwRelink() could print out garbage pointer (thanks mac@phobos.ca)]
**          [added array destructor for C++ (thanks rdasilva@connecttel.com)]
**          [added mutex support (thanks rdasilva@connecttel.com)]
** 010531 JLI  [2.67 fix: mwMutexXXX() was declared even if MW_HAVE_MUTEX was not defined]
** 010619 JLI  [2.68 fix: mwRealloc() could leave the mutex locked]
** 020918 JLI  [2.69 changed to GPL, added C++ array allocation by Howard Cohen]
** 030212 JLI  [2.70 mwMalloc() bug for very large allocations (4GB on 32bits)]
** 030520 JLI  [2.71 added ULONG_LONG_MAX as a 64-bit detector (thanks Sami Salonen)]
*/

#ifdef MEMWATCH

#define __MEMWATCH_C 1

#ifdef MW_NOCPP
#define MEMWATCH_NOCPP
#endif
#ifdef MW_STDIO
#define MEMWATCH_STDIO
#endif

/***********************************************************************
** Include files
***********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include <time.h>
#include <limits.h>
#include "memwatch.h"

#ifndef toupper
#include <ctype.h>
#endif

#if defined(WIN32) || defined(__WIN32__)
#define MW_HAVE_MUTEX 1
#include <windows.h>
#endif

#if defined(MW_PTHREADS) || defined(HAVE_PTHREAD_H)
#define MW_HAVE_MUTEX 1
#include <pthread.h>
#endif

/***********************************************************************
** Defines & other weird stuff
***********************************************************************/

/*lint -save -e767 */
#define VERSION     "2.71"         /* the current version number */
#define CHKVAL(mw)  (0xFE0180L^(long)mw->count^(long)mw->size^(long)mw->line)
#define FLUSH()     mwFlush()
#define TESTS(f,l)  if(mwTestAlways) (void)mwTestNow(f,l,1)
#define PRECHK      0x01234567L
#define POSTCHK     0x76543210L
#define mwBUFFER_TO_MW(p) ( (mwData*) (void*) ( ((char*)p)-mwDataSize-mwOverflowZoneSize ) )
/*lint -restore */

#define MW_NML      0x0001

#ifdef _MSC_VER
#define COMMIT "c"  /* Microsoft C requires the 'c' to perform as desired */
#else
#define COMMIT ""   /* Normal ANSI */
#endif /* _MSC_VER */

#ifdef __cplusplus
#define CPPTEXT "++"
#else
#define CPPTEXT ""
#endif /* __cplusplus */

#ifdef MEMWATCH_STDIO
#define mwSTDERR stderr
#else
#define mwSTDERR mwLog
#endif

#ifdef MW_HAVE_MUTEX
#define MW_MUTEX_INIT()    mwMutexInit()
#define MW_MUTEX_TERM()    mwMutexTerm()
#define MW_MUTEX_LOCK()    mwMutexLock()
#define MW_MUTEX_UNLOCK()  mwMutexUnlock()
#else
#define MW_MUTEX_INIT()
#define MW_MUTEX_TERM()
#define MW_MUTEX_LOCK()
#define MW_MUTEX_UNLOCK()
#endif

/***********************************************************************
** If you really, really know what you're doing,
** you can predefine these things yourself.
***********************************************************************/

#ifndef mwBYTE_DEFINED
# if CHAR_BIT != 8
#  error need CHAR_BIT to be 8!
# else
typedef unsigned char mwBYTE;
#  define mwBYTE_DEFINED 1
# endif
#endif

#if defined(ULONGLONG_MAX) || defined(ULLONG_MAX) || defined(_UI64_MAX) || defined(ULONG_LONG_MAX)
# define mw64BIT 1
# define mwROUNDALLOC_DEFAULT 8
#else
# if UINT_MAX <= 0xFFFFUL
#  define mw16BIT 1
#  define mwROUNDALLOC_DEFAULT   2
# else
#  if ULONG_MAX > 0xFFFFFFFFUL
#   define mw64BIT 1
#   define mwROUNDALLOC_DEFAULT  8
#  else
#   define mw32BIT 1
#   define mwROUNDALLOC_DEFAULT  4
#  endif
# endif
#endif

/* mwROUNDALLOC is the number of bytes to */
/* round up to, to ensure that the end of */
/* the buffer is suitable for storage of */
/* any kind of object */
#ifndef mwROUNDALLOC
# define mwROUNDALLOC mwROUNDALLOC_DEFAULT
#endif

#ifndef mwDWORD_DEFINED
#if ULONG_MAX == 0xFFFFFFFFUL
typedef unsigned long mwDWORD;
#define mwDWORD_DEFINED "unsigned long"
#endif
#endif

#ifndef mwDWORD_DEFINED
#if UINT_MAX == 0xFFFFFFFFUL
typedef unsigned int mwDWORD;
#define mwDWORD_DEFINED "unsigned int"
#endif
#endif

#ifndef mwDWORD_DEFINED
#if USHRT_MAX == 0xFFFFFFFFUL
typedef unsigned short mwDWORD;
#define mwDWORD_DEFINED "unsigned short"
#endif
#endif

#ifndef mwBYTE_DEFINED
#error "can't find out the correct type for a 8 bit scalar"
#endif

#ifndef mwDWORD_DEFINED
#error "can't find out the correct type for a 32 bit scalar"
#endif

/***********************************************************************
** Typedefs & structures
***********************************************************************/

/* main data holding area, precedes actual allocation */
typedef struct mwData_ mwData;
struct mwData_ {
    mwData*     prev;   /* previous allocation in chain */
    mwData*     next;   /* next allocation in chain */
    const char* file;   /* file name where allocated */
    long        count;  /* action count */
    long        check;  /* integrity check value */
#if 0
    long        crc;    /* data crc value */
#endif
    size_t      size;   /* size of allocation */
    int         line;   /* line number where allocated */
    unsigned    flag;   /* flag word */
    };

/* statistics structure */
typedef struct mwStat_ mwStat;
struct mwStat_ {
    mwStat*     next;   /* next statistic buffer */
    const char* file;
    long        total;  /* total bytes allocated */
    long        num;    /* total number of allocations */
    long        max;    /* max allocated at one time */
    long        curr;   /* current allocations */
    int         line;
    };

/* grabbing structure, 1K in size */
typedef struct mwGrabData_ mwGrabData;
struct mwGrabData_ {
    mwGrabData* next;
    int         type;
    char        blob[ 1024 - sizeof(mwGrabData*) - sizeof(int) ];
    };

typedef struct mwMarker_ mwMarker;
struct mwMarker_ {
    void *host;
    char *text;
    mwMarker *next;
    int level;
    };

#if defined(WIN32) || defined(__WIN32__)
typedef HANDLE          mwMutex;
#endif

#if defined(MW_PTHREADS) || defined(HAVE_PTHREAD_H)
typedef pthread_mutex_t mwMutex;
#endif

/***********************************************************************
** Static variables
***********************************************************************/

static int      mwInited =      0;
static int      mwInfoWritten = 0;
static int      mwUseAtexit =   0;
static FILE*    mwLog =         NULL;
static int      mwFlushing =    0;
static int      mwStatLevel =   MW_STAT_DEFAULT;
static int      mwNML =         MW_NML_DEFAULT;
static int      mwFBI =         0;
static long     mwAllocLimit =  0L;
static int      mwUseLimit =    0;

static long     mwNumCurAlloc = 0L;
static mwData*  mwHead =      NULL;
static mwData*  mwTail =      NULL;
static int     mwDataSize =   0;
static unsigned char mwOverflowZoneTemplate[] = "mEmwAtch";
static int     mwOverflowZoneSize = mwROUNDALLOC;

static void     (*mwOutFunction)(int) = NULL;
static int      (*mwAriFunction)(const char*) = NULL;
static int      mwAriAction = MW_ARI_ABORT;

static char     mwPrintBuf[MW_TRACE_BUFFER+8];

static unsigned long mwCounter = 0L;
static long     mwErrors =      0L;

static int      mwTestFlags =   0;
static int      mwTestAlways =  0;

static FILE*    mwLogB1 =       NULL;
static int      mwFlushingB1 =  0;

static mwStat*  mwStatList = NULL;
static long     mwStatTotAlloc = 0L;
static long     mwStatMaxAlloc = 0L;
static long     mwStatNumAlloc = 0L;
static long     mwStatCurAlloc = 0L;
static long     mwNmlNumAlloc = 0L;
static long     mwNmlCurAlloc = 0L;

static mwGrabData* mwGrabList = NULL;
static long     mwGrabSize = 0L;

static void *   mwLastFree[MW_FREE_LIST];
static const char *mwLFfile[MW_FREE_LIST];
static int      mwLFline[MW_FREE_LIST];
static int      mwLFcur = 0;

static mwMarker* mwFirstMark = NULL;

static FILE*    mwLogB2 =       NULL;
static int      mwFlushingB2 =  0;

#ifdef MW_HAVE_MUTEX
static mwMutex mwGlobalMutex;
#endif

/***********************************************************************
** Static function declarations
***********************************************************************/

static void     mwAutoInit( void );
static FILE*    mwLogR( void );
static void     mwLogW( FILE* );
static int      mwFlushR( void );
static void     mwFlushW( int );
static void     mwFlush( void );
static void     mwIncErr( void );
static void     mwUnlink( mwData*, const char* file, int line );
static int      mwRelink( mwData*, const char* file, int line );
static int      mwIsHeapOK( mwData *mw );
static int      mwIsOwned( mwData* mw, const char* file, int line );
static int      mwTestBuf( mwData* mw, const char* file, int line );
static void     mwDefaultOutFunc( int );
static void     mwWrite( const char* format, ... );
static void     mwLogFile( const char* name );
static size_t   mwFreeUp( size_t, int );
static const void *mwTestMem( const void *, unsigned, int );
static int      mwStrCmpI( const char *s1, const char *s2 );
static int      mwTestNow( const char *file, int line, int always_invoked );
static void     mwDropAll( void );
static const char *mwGrabType( int type );
static unsigned mwGrab_( unsigned kb, int type, int silent );
static unsigned mwDrop_( unsigned kb, int type, int silent );
static int      mwARI( const char* text );
static void     mwStatReport( void );
static mwStat*  mwStatGet( const char*, int, int );
static void     mwStatAlloc( size_t, const char*, int );
static void     mwStatFree( size_t, const char*, int );
static int     mwCheckOF( const void * p );
static void    mwWriteOF( void * p );
static char    mwDummy( char c );
#ifdef MW_HAVE_MUTEX
static void    mwMutexInit( void );
static void    mwMutexTerm( void );
static void    mwMutexLock( void );
static void    mwMutexUnlock( void );
#endif

/***********************************************************************
** System functions
***********************************************************************/

void mwInit( void ) {
    time_t tid;

    if( mwInited++ > 0 ) return;

   MW_MUTEX_INIT();

    /* start a log if none is running */
    if( mwLogR() == NULL ) mwLogFile( "memwatch.log" );
    if( mwLogR() == NULL ) {
        int i;
        char buf[32];
        /* oops, could not open it! */
        /* probably because it's already open */
        /* so we try some other names */
        for( i=1; i<100; i++ ) {
            sprintf( buf, "memwat%02d.log", i );
            mwLogFile( buf );
            if( mwLogR() != NULL ) break;
            }
        }

    /* initialize the statistics */
    mwStatList = NULL;
    mwStatTotAlloc = 0L;
    mwStatCurAlloc = 0L;
    mwStatMaxAlloc = 0L;
    mwStatNumAlloc = 0L;
   mwNmlCurAlloc = 0L;
   mwNmlNumAlloc = 0L;

   /* calculate the buffer size to use for a mwData */
   mwDataSize = sizeof(mwData);
   while( mwDataSize % mwROUNDALLOC ) mwDataSize ++;

    /* write informational header if needed */
    if( !mwInfoWritten ) {
        mwInfoWritten = 1;
        (void) time( &tid );
        mwWrite(
            "\n============="
            " MEMWATCH " VERSION " Copyright (C) 1992-1999 Johan Lindh "
            "=============\n");
        mwWrite( "\nStarted at %s\n", ctime( &tid ) );

/**************************************************************** Generic */
      mwWrite( "Modes: " );
#ifdef mwNew
        mwWrite( "C++ " );
#endif /* mwNew */
#ifdef __STDC__
        mwWrite( "__STDC__ " );
#endif /* __STDC__ */
#ifdef mw16BIT
      mwWrite( "16-bit " );
#endif
#ifdef mw32BIT
      mwWrite( "32-bit " );
#endif
#ifdef mw64BIT
      mwWrite( "64-bit " );
#endif
      mwWrite( "mwDWORD==(" mwDWORD_DEFINED ")\n" );
      mwWrite( "mwROUNDALLOC==%d sizeof(mwData)==%d mwDataSize==%d\n",
         mwROUNDALLOC, sizeof(mwData), mwDataSize );
/**************************************************************** Generic */

/************************************************************ Microsoft C */
#ifdef _MSC_VER
        mwWrite( "Compiled using Microsoft C" CPPTEXT
            " %d.%02d\n", _MSC_VER / 100, _MSC_VER % 100 );
#endif /* _MSC_VER */
/************************************************************ Microsoft C */

/************************************************************** Borland C */
#ifdef __BORLANDC__
        mwWrite( "Compiled using Borland C"
#ifdef __cplusplus
            "++ %d.%01d\n", __BCPLUSPLUS__/0x100, (__BCPLUSPLUS__%0x100)/0x10 );
#else
            " %d.%01d\n", __BORLANDC__/0x100, (__BORLANDC__%0x100)/0x10 );
#endif /* __cplusplus */
#endif /* __BORLANDC__ */
/************************************************************** Borland C */

/************************************************************** Watcom C */
#ifdef __WATCOMC__
        mwWrite( "Compiled using Watcom C %d.%02d ",
            __WATCOMC__/100, __WATCOMC__%100 );
#ifdef __FLAT__
        mwWrite( "(32-bit flat model)" );
#endif /* __FLAT__ */
        mwWrite( "\n" );
#endif /* __WATCOMC__ */
/************************************************************** Watcom C */

        mwWrite( "\n" );
        FLUSH();
        }

    if( mwUseAtexit ) (void) atexit( mwAbort );
    return;
    }

void mwAbort( void ) {
    mwData *mw;
    mwMarker *mrk;
    char *data;
    time_t tid;
    int c, i, j;
   int errors;

    tid = time( NULL );
    mwWrite( "\nStopped at %s\n", ctime( &tid) );

    if( !mwInited )
        mwWrite( "internal: mwAbort(): MEMWATCH not initialized!\n" );

    /* release the grab list */
    mwDropAll();

    /* report mwMarked items */
    while( mwFirstMark ) {
        mrk = mwFirstMark->next;
        mwWrite( "mark: %p: %s\n", mwFirstMark->host, mwFirstMark->text );
        free( mwFirstMark->text );
        free( mwFirstMark );
        mwFirstMark = mrk;
        mwErrors ++;
        }

    /* release all still allocated memory */
   errors = 0;
    while( mwHead != NULL && errors < 3 ) {
      if( !mwIsOwned(mwHead, __FILE__, __LINE__ ) ) {
         if( errors < 3 )
         {
            errors ++;
            mwWrite( "internal: NML/unfreed scan restarting\n" );
            FLUSH();
            mwHead = mwHead;
            continue;
         }
         mwWrite( "internal: NML/unfreed scan aborted, heap too damaged\n" );
         FLUSH();
         break;
         }
        mwFlushW(0);
        if( !(mwHead->flag & MW_NML) ) {
            mwErrors++;
            data = ((char*)mwHead)+mwDataSize;
            mwWrite( "unfreed: <%ld> %s(%d), %ld bytes at %p ",
                mwHead->count, mwHead->file, mwHead->line, (long)mwHead->size, data+mwOverflowZoneSize );
            if( mwCheckOF( data ) ) {
                mwWrite( "[underflowed] ");
                FLUSH();
                }
            if( mwCheckOF( (data+mwOverflowZoneSize+mwHead->size) ) ) {
                mwWrite( "[overflowed] ");
                FLUSH();
                }
            mwWrite( " \t{" );
            j = 16; if( mwHead->size < 16 ) j = (int) mwHead->size;
            for( i=0;i<16;i++ ) {
                if( i<j ) mwWrite( "%02X ",
                    (unsigned char) *(data+mwOverflowZoneSize+i) );
                else mwWrite( ".. " );
                }
            for( i=0;i<j;i++ ) {
                c = *(data+mwOverflowZoneSize+i);
                if( c < 32 || c > 126 ) c = '.';
                mwWrite( "%c", c );
                }
            mwWrite( "}\n" );
         mw = mwHead;
         mwUnlink( mw, __FILE__, __LINE__ );
            free( mw );
            }
        else {
            data = ((char*)mwHead) + mwDataSize + mwOverflowZoneSize;
            if( mwTestMem( data, mwHead->size, MW_VAL_NML ) ) {
                mwErrors++;
                mwWrite( "wild pointer: <%ld> NoMansLand %p alloc'd at %s(%d)\n",
                    mwHead->count, data + mwOverflowZoneSize, mwHead->file, mwHead->line );
                FLUSH();
                }
         mwNmlNumAlloc --;
         mwNmlCurAlloc -= mwHead->size;
         mw = mwHead;
         mwUnlink( mw, __FILE__, __LINE__ );
            free( mw );
            }
        }

   if( mwNmlNumAlloc ) mwWrite("internal: NoMansLand block counter %ld, not zero\n", mwNmlNumAlloc );
   if( mwNmlCurAlloc ) mwWrite("internal: NoMansLand byte counter %ld, not zero\n", mwNmlCurAlloc );

    /* report statistics */
    mwStatReport();
    FLUSH();

    mwInited = 0;
    mwHead = mwTail = NULL;
    if( mwErrors )
        fprintf(mwSTDERR,"MEMWATCH detected %ld anomalies\n",mwErrors);
    mwLogFile( NULL );
    mwErrors = 0;

    MW_MUTEX_TERM();

    }

void mwTerm( void ) {
    if( mwInited == 1 )
    {
        mwAbort();
        return;
    }
    if( !mwInited )
        mwWrite("internal: mwTerm(): MEMWATCH has not been started!\n");
    else
        mwInited --;
    }

void mwStatistics( int level )
{
    mwAutoInit();
    if( level<0 ) level=0;
    if( mwStatLevel != level )
    {
      mwWrite( "statistics: now collecting on a %s basis\n",
         level<1?"global":(level<2?"module":"line") );
       mwStatLevel = level;
   }
}

void mwAutoCheck( int onoff ) {
    mwAutoInit();
    mwTestAlways = onoff;
    if( onoff ) mwTestFlags = MW_TEST_ALL;
    }

void mwSetOutFunc( void (*func)(int) ) {
    mwAutoInit();
    mwOutFunction = func;
    }

static void mwWriteOF( void *p )
{
   int i;
   unsigned char *ptr;
   ptr = (unsigned char*) p;
   for( i=0; i<mwOverflowZoneSize; i++ )
   {
      *(ptr+i) = mwOverflowZoneTemplate[i%8];
   }
   return;
}

static int mwCheckOF( const void *p )
{
   int i;
   const unsigned char *ptr;
   ptr = (const unsigned char *) p;
   for( i=0; i<mwOverflowZoneSize; i++ )
   {
      if( *(ptr+i) != mwOverflowZoneTemplate[i%8] )
         return 1; /* errors found */
   }
   return 0; /* no errors */
}

int mwTest( const char *file, int line, int items ) {
    mwAutoInit();
    mwTestFlags = items;
    return mwTestNow( file, line, 0 );
    }

/*
** Returns zero if there are no errors.
** Returns nonzero if there are errors.
*/
int mwTestBuffer( const char *file, int line, void *p ) {
    mwData* mw;

    mwAutoInit();

    /* do the quick ownership test */
    mw = (mwData*) mwBUFFER_TO_MW( p );

    if( mwIsOwned( mw, file, line ) ) {
        return mwTestBuf( mw, file, line );
      }
   return 1;
   }

void mwBreakOut( const char* cause ) {
    fprintf(mwSTDERR, "breakout: %s\n", cause);
    mwWrite("breakout: %s\n", cause );
    return;
    }

/*
** 981217 JLI: is it possible that ->next is not always set?
*/
void * mwMark( void *p, const char *desc, const char *file, unsigned line ) {
    mwMarker *mrk;
    unsigned n, isnew;
    char *buf;
    int tot, oflow = 0;
    char wherebuf[128];

    mwAutoInit();
    TESTS(NULL,0);

    if( desc == NULL ) desc = "unknown";
    if( file == NULL ) file = "unknown";

    tot = sprintf( wherebuf, "%.48s called from %s(%d)", desc, file, line );
    if( tot >= (int)sizeof(wherebuf) ) { wherebuf[sizeof(wherebuf)-1] = 0; oflow = 1; }

    if( p == NULL ) {
        mwWrite("mark: %s(%d), no mark for NULL:'%s' may be set\n", file, line, desc );
        return p;
        }

   if( mwFirstMark != NULL && !mwIsReadAddr( mwFirstMark, sizeof( mwMarker ) ) )
   {
      mwWrite("mark: %s(%d), mwFirstMark (%p) is trashed, can't mark for %s\n",
         file, line, mwFirstMark, desc );
      return p;
   }

    for( mrk=mwFirstMark; mrk; mrk=mrk->next )
   {
      if( mrk->next != NULL && !mwIsReadAddr( mrk->next, sizeof( mwMarker ) ) )
      {
         mwWrite("mark: %s(%d), mark(%p)->next(%p) is trashed, can't mark for %s\n",
            file, line, mrk, mrk->next, desc );
         return p;
      }
      if( mrk->host == p ) break;
   }

    if( mrk == NULL ) {
        isnew = 1;
        mrk = (mwMarker*) malloc( sizeof( mwMarker ) );
        if( mrk == NULL ) {
            mwWrite("mark: %s(%d), no mark for %p:'%s', out of memory\n", file, line, p, desc );
            return p;
            }
      mrk->next = NULL;
        n = 0;
        }
    else {
        isnew = 0;
        n = strlen( mrk->text );
        }

    n += strlen( wherebuf );
    buf = (char*) malloc( n+3 );
    if( buf == NULL ) {
        if( isnew ) free( mrk );
        mwWrite("mark: %s(%d), no mark for %p:'%s', out of memory\n", file, line, p, desc );
        return p;
        }

    if( isnew ) {
        memcpy( buf, wherebuf, n+1 );
        mrk->next = mwFirstMark;
        mrk->host = p;
        mrk->text = buf;
        mrk->level = 1;
        mwFirstMark = mrk;
        }
    else {
        strcpy( buf, mrk->text );
        strcat( buf, ", " );
        strcat( buf, wherebuf );
        free( mrk->text );
        mrk->text = buf;
        mrk->level ++;
        }

    if( oflow ) {
        mwIncErr();
        mwTrace( " [WARNING: OUTPUT BUFFER OVERFLOW - SYSTEM UNSTABLE]\n" );
        }
    return p;
    }

void* mwUnmark( void *p, const char *file, unsigned line ) {
    mwMarker *mrk, *prv;
    mrk = mwFirstMark;
    prv = NULL;
    while( mrk ) {
        if( mrk->host == p ) {
            if( mrk->level < 2 ) {
                if( prv ) prv->next = mrk->next;
                else mwFirstMark = mrk->next;
                free( mrk->text );
                free( mrk );
                return p;
                }
            mrk->level --;
            return p;
            }
        prv = mrk;
        mrk = mrk->next;
        }
    mwWrite("mark: %s(%d), no mark found for %p\n", file, line, p );
    return p;
    }


/***********************************************************************
** Abort/Retry/Ignore handlers
***********************************************************************/

static int mwARI( const char *estr ) {
    char inbuf[81];
    int c;
    fprintf(mwSTDERR, "\n%s\nMEMWATCH: Abort, Retry or Ignore? ", estr);
    (void) fgets(inbuf,sizeof(inbuf),stdin);
   for( c=0; inbuf[c] && inbuf[c] <= ' '; c++ ) ;
    c = inbuf[c];
    if( c == 'R' || c == 'r' ) {
        mwBreakOut( estr );
        return MW_ARI_RETRY;
        }
    if( c == 'I' || c == 'i' ) return MW_ARI_IGNORE;
    return MW_ARI_ABORT;
    }

/* standard ARI handler (exported) */
int mwAriHandler( const char *estr ) {
    mwAutoInit();
    return mwARI( estr );
    }

/* used to set the ARI function */
void mwSetAriFunc( int (*func)(const char *) ) {
    mwAutoInit();
    mwAriFunction = func;
    }

/***********************************************************************
** Allocation handlers
***********************************************************************/

void* mwMalloc( size_t size, const char* file, int line) {
    size_t needed;
    mwData *mw;
    char *ptr;
    void *p;

    mwAutoInit();

   MW_MUTEX_LOCK();

    TESTS(file,line);

    mwCounter ++;
    needed = mwDataSize + mwOverflowZoneSize*2 + size;
    if( needed < size )
    {
      /* theoretical case: req size + mw overhead exceeded size_t limits */
      return NULL;
    }

    /* if this allocation would violate the limit, fail it */
    if( mwUseLimit && ((long)size + mwStatCurAlloc > mwAllocLimit) ) {
        mwWrite( "limit fail: <%ld> %s(%d), %ld wanted %ld available\n",
            mwCounter, file, line, (long)size, mwAllocLimit - mwStatCurAlloc );
        mwIncErr();
        FLUSH();
      MW_MUTEX_UNLOCK();
        return NULL;
        }

    mw = (mwData*) malloc( needed );
    if( mw == NULL ) {
        if( mwFreeUp(needed,0) >= needed ) {
            mw = (mwData*) malloc(needed);
            if( mw == NULL ) {
                mwWrite( "internal: mwFreeUp(%u) reported success, but malloc() fails\n", needed );
                mwIncErr();
                FLUSH();
                }
            }
        if( mw == NULL ) {
            mwWrite( "fail: <%ld> %s(%d), %ld wanted %ld allocated\n",
                mwCounter, file, line, (long)size, mwStatCurAlloc );
            mwIncErr();
            FLUSH();
         MW_MUTEX_UNLOCK();
            return NULL;
            }
        }

    mw->count = mwCounter;
    mw->prev = NULL;
    mw->next = mwHead;
    mw->file = file;
    mw->size = size;
    mw->line = line;
    mw->flag = 0;
    mw->check = CHKVAL(mw);

    if( mwHead ) mwHead->prev = mw;
    mwHead = mw;
    if( mwTail == NULL ) mwTail = mw;

    ptr = ((char*)mw) + mwDataSize;
   mwWriteOF( ptr ); /* '*(long*)ptr = PRECHK;' */
    ptr += mwOverflowZoneSize;
    p = ptr;
    memset( ptr, MW_VAL_NEW, size );
    ptr += size;
    mwWriteOF( ptr ); /* '*(long*)ptr = POSTCHK;' */

    mwNumCurAlloc ++;
    mwStatCurAlloc += (long) size;
    mwStatTotAlloc += (long) size;
    if( mwStatCurAlloc > mwStatMaxAlloc )
        mwStatMaxAlloc = mwStatCurAlloc;
    mwStatNumAlloc ++;

    if( mwStatLevel ) mwStatAlloc( size, file, line );

   MW_MUTEX_UNLOCK();
    return p;
    }

void* mwRealloc( void *p, size_t size, const char* file, int line) {
    int oldUseLimit, i;
    mwData *mw;
    char *ptr;

    mwAutoInit();

    if( p == NULL ) return mwMalloc( size, file, line );
    if( size == 0 ) { mwFree( p, file, line ); return NULL; }

   MW_MUTEX_LOCK();

    /* do the quick ownership test */
    mw = (mwData*) mwBUFFER_TO_MW( p );
    if( mwIsOwned( mw, file, line ) ) {

      /* if the buffer is an NML, treat this as a double-free */
      if( mw->flag & MW_NML )
      {
            mwIncErr();
         if( *((unsigned char*)(mw)+mwDataSize+mwOverflowZoneSize) != MW_VAL_NML )
         {
            mwWrite( "internal: <%ld> %s(%d), no-mans-land MW-%p is corrupted\n",
               mwCounter, file, line, mw );
         }
         goto check_dbl_free;
      }

        /* if this allocation would violate the limit, fail it */
        if( mwUseLimit && ((long)size + mwStatCurAlloc - (long)mw->size > mwAllocLimit) ) {
            TESTS(file,line);
            mwCounter ++;
            mwWrite( "limit fail: <%ld> %s(%d), %ld wanted %ld available\n",
                mwCounter, file, line, (unsigned long)size - mw->size, mwAllocLimit - mwStatCurAlloc );
            mwIncErr();
            FLUSH();
         MW_MUTEX_UNLOCK();
            return NULL;
            }

        /* fake realloc operation */
        oldUseLimit = mwUseLimit;
        mwUseLimit = 0;
        ptr = (char*) mwMalloc( size, file, line );
        if( ptr != NULL ) {
            if( size < mw->size )
                memcpy( ptr, p, size );
            else
                memcpy( ptr, p, mw->size );
            mwFree( p, file, line );
            }
        mwUseLimit = oldUseLimit;
      MW_MUTEX_UNLOCK();
        return (void*) ptr;
        }

    /* Unknown pointer! */

    /* using free'd pointer? */
check_dbl_free:
    for(i=0;i<MW_FREE_LIST;i++) {
        if( mwLastFree[i] == p ) {
            mwIncErr();
            mwWrite( "realloc: <%ld> %s(%d), %p was"
                " freed from %s(%d)\n",
                mwCounter, file, line, p,
                mwLFfile[i], mwLFline[i] );
            FLUSH();
         MW_MUTEX_UNLOCK();
            return NULL;
            }
        }

    /* some weird pointer */
    mwIncErr();
    mwWrite( "realloc: <%ld> %s(%d), unknown pointer %p\n",
        mwCounter, file, line, p );
    FLUSH();
   MW_MUTEX_UNLOCK();
    return NULL;
    }

char *mwStrdup( const char* str, const char* file, int line ) {
    size_t len;
    char *newstring;

   MW_MUTEX_LOCK();

    if( str == NULL ) {
        mwIncErr();
        mwWrite( "strdup: <%ld> %s(%d), strdup(NULL) called\n",
            mwCounter, file, line );
        FLUSH();
      MW_MUTEX_UNLOCK();
        return NULL;
        }

    len = strlen( str ) + 1;
    newstring = (char*) mwMalloc( len, file, line );
    if( newstring != NULL ) memcpy( newstring, str, len );
   MW_MUTEX_UNLOCK();
    return newstring;
    }

void mwFree( void* p, const char* file, int line ) {
    int i;
    mwData* mw;
    char buffer[ sizeof(mwData) + (mwROUNDALLOC*3) + 64 ];

    /* this code is in support of C++ delete */
    if( file == NULL ) {
        mwFree_( p );
      MW_MUTEX_UNLOCK();
        return;
        }

    mwAutoInit();

   MW_MUTEX_LOCK();
    TESTS(file,line);
    mwCounter ++;

    /* on NULL free, write a warning and return */
    if( p == NULL ) {
        mwWrite( "NULL free: <%ld> %s(%d), NULL pointer free'd\n",
            mwCounter, file, line );
        FLUSH();
      MW_MUTEX_UNLOCK();
        return;
        }

    /* do the quick ownership test */
    mw = (mwData*) mwBUFFER_TO_MW( p );

    if( mwIsOwned( mw, file, line ) ) {
        (void) mwTestBuf( mw, file, line );

      /* if the buffer is an NML, treat this as a double-free */
      if( mw->flag & MW_NML )
      {
         if( *(((unsigned char*)mw)+mwDataSize+mwOverflowZoneSize) != MW_VAL_NML )
         {
            mwWrite( "internal: <%ld> %s(%d), no-mans-land MW-%p is corrupted\n",
               mwCounter, file, line, mw );
         }
         goto check_dbl_free;
      }

        /* update the statistics */
        mwNumCurAlloc --;
        mwStatCurAlloc -= (long) mw->size;
        if( mwStatLevel ) mwStatFree( mw->size, mw->file, mw->line );

        /* we should either free the allocation or keep it as NML */
        if( mwNML ) {
            mw->flag |= MW_NML;
         mwNmlNumAlloc ++;
         mwNmlCurAlloc += (long) mw->size;
            memset( ((char*)mw)+mwDataSize+mwOverflowZoneSize, MW_VAL_NML, mw->size );
            }
        else {
            /* unlink the allocation, and enter the post-free data */
            mwUnlink( mw, file, line );
            memset( mw, MW_VAL_DEL,
                mw->size + mwDataSize+mwOverflowZoneSize+mwOverflowZoneSize );
            if( mwFBI ) {
                memset( mw, '.', mwDataSize + mwOverflowZoneSize );
                sprintf( buffer, "FBI<%ld>%s(%d)", mwCounter, file, line );
                strncpy( (char*)(void*)mw, buffer, mwDataSize + mwOverflowZoneSize );
                }
            free( mw );
            }

        /* add the pointer to the last-free track */
        mwLFfile[ mwLFcur ] = file;
        mwLFline[ mwLFcur ] = line;
        mwLastFree[ mwLFcur++ ] = p;
        if( mwLFcur == MW_FREE_LIST ) mwLFcur = 0;

      MW_MUTEX_UNLOCK();
        return;
        }

    /* check for double-freeing */
check_dbl_free:
    for(i=0;i<MW_FREE_LIST;i++) {
        if( mwLastFree[i] == p ) {
            mwIncErr();
            mwWrite( "double-free: <%ld> %s(%d), %p was"
                " freed from %s(%d)\n",
                mwCounter, file, line, p,
                mwLFfile[i], mwLFline[i] );
            FLUSH();
         MW_MUTEX_UNLOCK();
            return;
            }
        }

    /* some weird pointer... block the free */
    mwIncErr();
    mwWrite( "WILD free: <%ld> %s(%d), unknown pointer %p\n",
        mwCounter, file, line, p );
    FLUSH();
   MW_MUTEX_UNLOCK();
    return;
    }

void* mwCalloc( size_t a, size_t b, const char *file, int line ) {
    void *p;
    size_t size = a * b;
    p = mwMalloc( size, file, line );
    if( p == NULL ) return NULL;
    memset( p, 0, size );
    return p;
    }

void mwFree_( void *p ) {
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
   MW_MUTEX_UNLOCK();
    free(p);
    }

void* mwMalloc_( size_t size ) {
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
   MW_MUTEX_UNLOCK();
    return malloc( size );
    }

void* mwRealloc_( void *p, size_t size ) {
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
   MW_MUTEX_UNLOCK();
    return realloc( p, size );
    }

void* mwCalloc_( size_t a, size_t b ) {
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
   MW_MUTEX_UNLOCK();
    return calloc( a, b );
    }

void mwFlushNow( void ) {
    if( mwLogR() ) fflush( mwLogR() );
    return;
    }

void mwDoFlush( int onoff ) {
    mwFlushW( onoff<1?0:onoff );
    if( onoff ) if( mwLogR() ) fflush( mwLogR() );
    return;
    }

void mwLimit( long lim ) {
    TESTS(NULL,0);
    mwWrite("limit: old limit = ");
    if( !mwAllocLimit ) mwWrite( "none" );
    else mwWrite( "%ld bytes", mwAllocLimit );
    mwWrite( ", new limit = ");
    if( !lim ) {
        mwWrite( "none\n" );
        mwUseLimit = 0;
        }
    else {
        mwWrite( "%ld bytes\n", lim );
        mwUseLimit = 1;
        }
    mwAllocLimit = lim;
    FLUSH();
    }

void mwSetAriAction( int action ) {
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
    mwAriAction = action;
   MW_MUTEX_UNLOCK();
    return;
    }

int mwAssert( int exp, const char *exps, const char *fn, int ln ) {
    int i;
    char buffer[MW_TRACE_BUFFER+8];
    if( exp ) {
      return 0;
      }
    mwAutoInit();
   MW_MUTEX_LOCK();
    TESTS(fn,ln);
    mwIncErr();
    mwCounter++;
    mwWrite( "assert trap: <%ld> %s(%d), %s\n", mwCounter, fn, ln, exps );
    if( mwAriFunction != NULL ) {
        sprintf( buffer, "MEMWATCH: assert trap: %s(%d), %s", fn, ln, exps );
        i = (*mwAriFunction)(buffer);
      switch( i ) {
         case MW_ARI_IGNORE:
               mwWrite( "assert trap: <%ld> IGNORED - execution continues\n", mwCounter );
            MW_MUTEX_UNLOCK();
              return 0;
         case MW_ARI_RETRY:
               mwWrite( "assert trap: <%ld> RETRY - executing again\n", mwCounter );
            MW_MUTEX_UNLOCK();
               return 1;
         }
        }
    else {
        if( mwAriAction & MW_ARI_IGNORE ) {
            mwWrite( "assert trap: <%ld> AUTO IGNORED - execution continues\n", mwCounter );
         MW_MUTEX_UNLOCK();
            return 0;
            }
        fprintf(mwSTDERR,"\nMEMWATCH: assert trap: %s(%d), %s\n", fn, ln, exps );
        }

    FLUSH();
    (void) mwTestNow( fn, ln, 1 );
    FLUSH();

   if( mwAriAction & MW_ARI_NULLREAD ) {
      /* This is made in an attempt to kick in */
      /* any debuggers or OS stack traces */
       FLUSH();
      /*lint -save -e413 */
      i = *((int*)NULL);
      mwDummy( (char)i );
      /*lint -restore */
      }

   MW_MUTEX_UNLOCK();
    exit(255);
    /* NOT REACHED - the return statement is in to keep */
    /* stupid compilers from squeaking about differing return modes. */
    /* Smart compilers instead say 'code unreachable...' */
    /*lint -save -e527 */
    return 0;
    /*lint -restore */
    }

int mwVerify( int exp, const char *exps, const char *fn, int ln ) {
    int i;
    char buffer[MW_TRACE_BUFFER+8];
    if( exp ) {
      return 0;
      }
    mwAutoInit();
   MW_MUTEX_LOCK();
    TESTS(fn,ln);
    mwIncErr();
    mwCounter++;
    mwWrite( "verify trap: <%ld> %s(%d), %s\n", mwCounter, fn, ln, exps );
    if( mwAriFunction != NULL ) {
        sprintf( buffer, "MEMWATCH: verify trap: %s(%d), %s", fn, ln, exps );
        i = (*mwAriFunction)(buffer);
        if( i == 0 ) {
            mwWrite( "verify trap: <%ld> IGNORED - execution continues\n", mwCounter );
         MW_MUTEX_UNLOCK();
            return 0;
            }
        if( i == 1 ) {
            mwWrite( "verify trap: <%ld> RETRY - executing again\n", mwCounter );
         MW_MUTEX_UNLOCK();
            return 1;
            }
        }
    else {
        if( mwAriAction & MW_ARI_NULLREAD ) {
            /* This is made in an attempt to kick in */
            /* any debuggers or OS stack traces */
          FLUSH();
            /*lint -save -e413 */
            i = *((int*)NULL);
         mwDummy( (char)i );
            /*lint -restore */
            }
        if( mwAriAction & MW_ARI_IGNORE ) {
            mwWrite( "verify trap: <%ld> AUTO IGNORED - execution continues\n", mwCounter );
         MW_MUTEX_UNLOCK();
            return 0;
            }
        fprintf(mwSTDERR,"\nMEMWATCH: verify trap: %s(%d), %s\n", fn, ln, exps );
        }
    FLUSH();
    (void) mwTestNow( fn, ln, 1 );
    FLUSH();
   MW_MUTEX_UNLOCK();
   exit(255);
    /* NOT REACHED - the return statement is in to keep */
    /* stupid compilers from squeaking about differing return modes. */
    /* Smart compilers instead say 'code unreachable...' */
    /*lint -save -e527 */
    return 0;
    /*lint -restore */
    }

void mwTrace( const char *format, ... ) {
    int tot, oflow = 0;
    va_list mark;

    mwAutoInit();
   MW_MUTEX_LOCK();
    TESTS(NULL,0);
    if( mwOutFunction == NULL ) mwOutFunction = mwDefaultOutFunc;

    va_start( mark, format );
    tot = vsprintf( mwPrintBuf, format, mark );
    va_end( mark );
    if( tot >= MW_TRACE_BUFFER ) { mwPrintBuf[MW_TRACE_BUFFER] = 0; oflow = 1; }
    for(tot=0;mwPrintBuf[tot];tot++)
        (*mwOutFunction)( mwPrintBuf[tot] );
    if( oflow ) {
        mwIncErr();
        mwTrace( " [WARNING: OUTPUT BUFFER OVERFLOW - SYSTEM UNSTABLE]\n" );
        }

    FLUSH();
   MW_MUTEX_UNLOCK();
    }


/***********************************************************************
** Grab & Drop
***********************************************************************/

unsigned mwGrab( unsigned kb ) {
    TESTS(NULL,0);
    return mwGrab_( kb, MW_VAL_GRB, 0 );
    }

unsigned mwDrop( unsigned kb ) {
    TESTS(NULL,0);
    return mwDrop_( kb, MW_VAL_GRB, 0 );
    }

static void mwDropAll() {
    TESTS(NULL,0);
    (void) mwDrop_( 0, MW_VAL_GRB, 0 );
    (void) mwDrop_( 0, MW_VAL_NML, 0 );
    if( mwGrabList != NULL )
        mwWrite( "internal: the grab list is not empty after mwDropAll()\n");
    }

static const char *mwGrabType( int type ) {
    switch( type ) {
        case MW_VAL_GRB:
            return "grabbed";
        case MW_VAL_NML:
            return "no-mans-land";
        default:
            /* do nothing */
            ;
        }
    return "<unknown type>";
    }

static unsigned mwGrab_( unsigned kb, int type, int silent ) {
    unsigned i = kb;
    mwGrabData *gd;
    if( !kb ) i = kb = 65000U;

    for(;kb;kb--) {
        if( mwUseLimit &&
            (mwStatCurAlloc + mwGrabSize + (long)sizeof(mwGrabData) > mwAllocLimit) ) {
            if( !silent ) {
                mwWrite("grabbed: all allowed memory to %s (%u kb)\n",
                    mwGrabType(type), i-kb);
                FLUSH();
                }
            return i-kb;
            }
        gd = (mwGrabData*) malloc( sizeof(mwGrabData) );
        if( gd == NULL ) {
            if( !silent ) {
                mwWrite("grabbed: all available memory to %s (%u kb)\n",
                    mwGrabType(type), i-kb);
                FLUSH();
                }
            return i-kb;
            }
        mwGrabSize += (long) sizeof(mwGrabData);
        gd->next = mwGrabList;
        memset( gd->blob, type, sizeof(gd->blob) );
        gd->type = type;
        mwGrabList = gd;
        }
    if( !silent ) {
        mwWrite("grabbed: %u kilobytes of %s memory\n", i, mwGrabType(type) );
        FLUSH();
        }
    return i;
    }

static unsigned mwDrop_( unsigned kb, int type, int silent ) {
    unsigned i = kb;
    mwGrabData *gd,*tmp,*pr;
    const void *p;

    if( mwGrabList == NULL && kb == 0 ) return 0;
    if( !kb ) i = kb = 60000U;

    pr = NULL;
    gd = mwGrabList;
    for(;kb;) {
        if( gd == NULL ) {
            if( i-kb > 0 && !silent ) {
                mwWrite("dropped: all %s memory (%u kb)\n", mwGrabType(type), i-kb);
                FLUSH();
                }
            return i-kb;
            }
        if( gd->type == type ) {
            if( pr ) pr->next = gd->next;
            kb --;
            tmp = gd;
            if( mwGrabList == gd ) mwGrabList = gd->next;
            gd = gd->next;
            p = mwTestMem( tmp->blob, sizeof( tmp->blob ), type );
            if( p != NULL ) {
                mwWrite( "wild pointer: <%ld> %s memory hit at %p\n",
                    mwCounter, mwGrabType(type), p );
                FLUSH();
                }
            mwGrabSize -= (long) sizeof(mwGrabData);
            free( tmp );
            }
        else {
            pr = gd;
            gd = gd->next;
            }
        }
    if( !silent ) {
        mwWrite("dropped: %u kilobytes of %s memory\n", i, mwGrabType(type) );
        FLUSH();
        }
    return i;
    }

/***********************************************************************
** No-Mans-Land
***********************************************************************/

void mwNoMansLand( int level ) {
    mwAutoInit();
    TESTS(NULL,0);
    switch( level ) {
        case MW_NML_NONE:
            (void) mwDrop_( 0, MW_VAL_NML, 0 );
            break;
        case MW_NML_FREE:
            break;
        case MW_NML_ALL:
            (void) mwGrab_( 0, MW_VAL_NML, 0 );
            break;
        default:
            return;
        }
    mwNML = level;
    }

/***********************************************************************
** Static functions
***********************************************************************/

static void mwAutoInit( void )
{
    if( mwInited ) return;
    mwUseAtexit = 1;
    mwInit();
    return;
}

static FILE *mwLogR() {
    if( (mwLog == mwLogB1) && (mwLog == mwLogB2) ) return mwLog;
    if( mwLog == mwLogB1 ) mwLogB2 = mwLog;
    if( mwLog == mwLogB2 ) mwLogB1 = mwLog;
    if( mwLogB1 == mwLogB2 ) mwLog = mwLogB1;
    if( (mwLog == mwLogB1) && (mwLog == mwLogB2) ) {
        mwWrite("internal: log file handle damaged and recovered\n");
        FLUSH();
        return mwLog;
        }
    fprintf(mwSTDERR,"\nMEMWATCH: log file handle destroyed, using mwSTDERR\n" );
    mwLog = mwLogB1 = mwLogB2 = mwSTDERR;
    return mwSTDERR;
    }

static void mwLogW( FILE *p ) {
    mwLog = mwLogB1 = mwLogB2 = p;
    }

static int mwFlushR() {
    if( (mwFlushing == mwFlushingB1) && (mwFlushing == mwFlushingB2) ) return mwFlushing;
    if( mwFlushing == mwFlushingB1 ) mwFlushingB2 = mwFlushing;
    if( mwFlushing == mwFlushingB2 ) mwFlushingB1 = mwFlushing;
    if( mwFlushingB1 == mwFlushingB2 ) mwFlushing = mwFlushingB1;
    if( (mwFlushing == mwFlushingB1) && (mwFlushing == mwFlushingB2) ) {
        mwWrite("internal: flushing flag damaged and recovered\n");
        FLUSH();
        return mwFlushing;
        }
    mwWrite("internal: flushing flag destroyed, so set to true\n");
    mwFlushing = mwFlushingB1 = mwFlushingB2 = 1;
    return 1;
    }

static void mwFlushW( int n ) {
    mwFlushing = mwFlushingB1 = mwFlushingB2 = n;
    }

static void mwIncErr() {
    mwErrors++;
    mwFlushW( mwFlushR()+1 );
    FLUSH();
    }

static void mwFlush() {
    if( mwLogR() == NULL ) return;
#ifdef MW_FLUSH
    fflush( mwLogR() );
#else
    if( mwFlushR() ) fflush( mwLogR() );
#endif
    return;
    }

static void mwUnlink( mwData* mw, const char* file, int line ) {
    if( mw->prev == NULL ) {
        if( mwHead != mw )
            mwWrite( "internal: <%ld> %s(%d), MW-%p: link1 NULL, but not head\n",
                mwCounter, file, line, mw );
        mwHead = mw->next;
        }
    else {
        if( mw->prev->next != mw )
            mwWrite( "internal: <%ld> %s(%d), MW-%p: link1 failure\n",
                mwCounter, file, line, mw );
        else mw->prev->next = mw->next;
        }
    if( mw->next == NULL ) {
        if( mwTail != mw )
            mwWrite( "internal: <%ld> %s(%d), MW-%p: link2 NULL, but not tail\n",
                mwCounter, file, line, mw );
        mwTail = mw->prev;
        }
    else {
        if( mw->next->prev != mw )
            mwWrite( "internal: <%ld> %s(%d), MW-%p: link2 failure\n",
                mwCounter, file, line, mw );
        else mw->next->prev = mw->prev;
        }
    }

/*
** Relinking tries to repair a damaged mw block.
** Returns nonzero if it thinks it successfully
** repaired the heap chain.
*/
static int mwRelink( mwData* mw, const char* file, int line ) {
    int fails;
    mwData *mw1, *mw2;
    long count, size;
    mwStat *ms;

   if( file == NULL ) file = "unknown";

    if( mw == NULL ) {
        mwWrite("relink: cannot repair MW at NULL\n");
        FLUSH();
        goto emergency;
        }

    if( !mwIsSafeAddr(mw, mwDataSize) ) {
        mwWrite("relink: MW-%p is a garbage pointer\n", mw);
        FLUSH();
        goto emergency;
        }

    mwWrite("relink: <%ld> %s(%d) attempting to repair MW-%p...\n", mwCounter, file, line, mw );
    FLUSH();
    fails = 0;

    /* Repair from head */
    if( mwHead != mw ) {
        if( !mwIsSafeAddr( mwHead, mwDataSize ) ) {
            mwWrite("relink: failed for MW-%p; head pointer destroyed\n", mw );
            FLUSH();
            goto emergency;
            }
        for( mw1=mwHead; mw1; mw1=mw1->next ) {
            if( mw1->next == mw ) {
                mw->prev = mw1;
                break;
                }
            if( mw1->next &&
                ( !mwIsSafeAddr(mw1->next, mwDataSize ) || mw1->next->prev != mw1) ) {
                mwWrite("relink: failed for MW-%p; forward chain fragmented at MW-%p: 'next' is %p\n", mw, mw1, mw1->next );
                FLUSH();
                goto emergency;
                }
            }
        if( mw1 == NULL ) {
            mwWrite("relink: MW-%p not found in forward chain search\n", mw );
            FLUSH();
            fails ++;
            }
        }
   else
   {
      mwWrite( "relink: MW-%p is the head (first) allocation\n", mw );
      if( mw->prev != NULL )
      {
         mwWrite( "relink: MW-%p prev pointer is non-NULL, you have a wild pointer\n", mw );
         mw->prev = NULL;
      }
   }

    /* Repair from tail */
    if( mwTail != mw ) {
        if( !mwIsSafeAddr( mwTail, mwDataSize ) ) {
            mwWrite("relink: failed for MW-%p; tail pointer destroyed\n", mw );
            FLUSH();
            goto emergency;
            }
        for( mw1=mwTail; mw1; mw1=mw1->prev ) {
            if( mw1->prev == mw ) {
                mw->next = mw1;
                break;
                }
            if( mw1->prev && (!mwIsSafeAddr(mw1->prev, mwDataSize ) || mw1->prev->next != mw1) ) {
                mwWrite("relink: failed for MW-%p; reverse chain fragmented at MW-%p, 'prev' is %p\n", mw, mw1, mw1->prev );
                FLUSH();
                goto emergency;
                }
            }
        if( mw1 == NULL ) {
            mwWrite("relink: MW-%p not found in reverse chain search\n", mw );
            FLUSH();
            fails ++;
            }
        }
   else
   {
      mwWrite( "relink: MW-%p is the tail (last) allocation\n", mw );
      if( mw->next != NULL )
      {
         mwWrite( "relink: MW-%p next pointer is non-NULL, you have a wild pointer\n", mw );
         mw->next = NULL;
      }
   }

    if( fails > 1 ) {
        mwWrite("relink: heap appears intact, MW-%p probably garbage pointer\n", mw );
        FLUSH();
        goto verifyok;
        }

    /* restore MW info where possible */
    if( mwIsReadAddr( mw->file, 1 ) ) {
        ms = mwStatGet( mw->file, -1, 0 );
        if( ms == NULL ) mw->file = "<relinked>";
        }
    mw->check = CHKVAL(mw);
    goto verifyok;

    /* Emergency repair */
    emergency:

    if( mwHead == NULL && mwTail == NULL )
    {
        if( mwStatCurAlloc == 0 )
            mwWrite("relink: <%ld> %s(%d) heap is empty, nothing to repair\n", mwCounter, file, line );
        else
            mwWrite("relink: <%ld> %s(%d) heap damaged beyond repair\n", mwCounter, file, line );
        FLUSH();
        return 0;
    }

    mwWrite("relink: <%ld> %s(%d) attempting emergency repairs...\n", mwCounter, file, line );
    FLUSH();

   if( mwHead == NULL || mwTail == NULL )
   {
      if( mwHead == NULL ) mwWrite("relink: mwHead is NULL, but mwTail is %p\n", mwTail );
      else mwWrite("relink: mwTail is NULL, but mwHead is %p\n", mwHead );
   }

    mw1=NULL;
    if( mwHead != NULL )
   {
      if( !mwIsReadAddr( mwHead, mwDataSize ) || mwHead->check != CHKVAL(mwHead) )
      {
         mwWrite("relink: mwHead (MW-%p) is damaged, skipping forward scan\n", mwHead );
         mwHead = NULL;
         goto scan_reverse;
      }
      if( mwHead->prev != NULL )
      {
         mwWrite("relink: the mwHead pointer's 'prev' member is %p, not NULL\n", mwHead->prev );
      }
        for( mw1=mwHead; mw1; mw1=mw1->next )
      {
         if( mw1->next )
         {
            if( !mwIsReadAddr(mw1->next,mwDataSize) ||
               !mw1->next->check != CHKVAL(mw1) ||
               mw1->next->prev != mw1 )
            {
               mwWrite("relink: forward chain's last intact MW is MW-%p, %ld %sbytes at %s(%d)\n",
                  mw1, mw1->size, (mw->flag & MW_NML)?"NoMansLand ":"", mw1->file, mw1->line );
               if( mwIsReadAddr(mw1->next,mwDataSize ) )
               {
                  mwWrite("relink: forward chain's first damaged MW is MW-%p, %ld %sbytes at %s(%d)\n",
                     mw1->next, mw1->size, (mw->flag & MW_NML)?"NoMansLand ":"",
                     mwIsReadAddr(mw1->file,16)?mw1->file:"<garbage-pointer>", mw1->line );
               }
               else
               {
                  mwWrite("relink: the 'next' pointer of this MW points to %p, which is out-of-legal-access\n",
                     mw1->next );
               }
               break;
            }
         }
        }
   }


scan_reverse:
    mw2=NULL;
    if( mwTail != NULL )
   {
      if( !mwIsReadAddr(mwTail,mwDataSize) || mwTail->check != CHKVAL(mwTail) )
      {
         mwWrite("relink: mwTail (%p) is damaged, skipping reverse scan\n", mwTail );
         mwTail = NULL;
         goto analyze;
      }
      if( mwTail->next != NULL )
      {
         mwWrite("relink: the mwTail pointer's 'next' member is %p, not NULL\n", mwTail->next );
      }
        for( mw2=mwTail; mw2; mw2=mw2->prev )
      {
            if( mw2->prev )
         {
            if( !mwIsReadAddr(mw2->prev,mwDataSize) ||
               !mw2->prev->check != CHKVAL(mw2) ||
               mw2->prev->next != mw2 )
            {
               mwWrite("relink: reverse chain's last intact MW is MW-%p, %ld %sbytes at %s(%d)\n",
                  mw2, mw2->size, (mw->flag & MW_NML)?"NoMansLand ":"", mw2->file, mw2->line );
               if( mwIsReadAddr(mw2->prev,mwDataSize ) )
               {
                  mwWrite("relink: reverse chain's first damaged MW is MW-%p, %ld %sbytes at %s(%d)\n",
                     mw2->prev, mw2->size, (mw->flag & MW_NML)?"NoMansLand ":"",
                     mwIsReadAddr(mw2->file,16)?mw2->file:"<garbage-pointer>", mw2->line );
               }
               else
               {
                  mwWrite("relink: the 'prev' pointer of this MW points to %p, which is out-of-legal-access\n",
                     mw2->prev );
               }
               break;
            }
         }
        }
   }

analyze:
   if( mwHead == NULL && mwTail == NULL )
   {
        mwWrite("relink: both head and tail pointers damaged, aborting program\n");
        mwFlushW(1);
        FLUSH();
        abort();
   }
   if( mwHead == NULL )
   {
      mwHead = mw2;
      mwWrite("relink: heap truncated, MW-%p designated as new mwHead\n", mw2 );
      mw2->prev = NULL;
      mw1 = mw2 = NULL;
   }
   if( mwTail == NULL )
   {
      mwTail = mw1;
      mwWrite("relink: heap truncated, MW-%p designated as new mwTail\n", mw1 );
      mw1->next = NULL;
      mw1 = mw2 = NULL;
   }
    if( mw1 == NULL && mw2 == NULL &&
        mwHead->prev == NULL && mwTail->next == NULL ) {
        mwWrite("relink: verifying heap integrity...\n" );
        FLUSH();
        goto verifyok;
        }
    if( mw1 && mw2 && mw1 != mw2 ) {
        mw1->next = mw2;
        mw2->prev = mw1;
        mwWrite("relink: emergency repairs successful, assessing damage...\n");
        FLUSH();
        }
    else {
        mwWrite("relink: heap totally destroyed, aborting program\n");
        mwFlushW(1);
        FLUSH();
        abort();
        }

    /* Verify by checking that the number of active allocations */
    /* match the number of entries in the chain */
verifyok:
    if( !mwIsHeapOK( NULL ) ) {
        mwWrite("relink: heap verification FAILS - aborting program\n");
        mwFlushW(1);
        FLUSH();
        abort();
        }
    for( size=count=0, mw1=mwHead; mw1; mw1=mw1->next ) {
        count ++;
        size += (long) mw1->size;
        }
    if( count == mwNumCurAlloc ) {
        mwWrite("relink: successful, ");
        if( size == mwStatCurAlloc ) {
            mwWrite("no allocations lost\n");
            }
        else {
            if( mw != NULL ) {
                mwWrite("size information lost for MW-%p\n", mw);
                mw->size = 0;
                }
            }
        }
    else {
        mwWrite("relink: partial, %ld MW-blocks of %ld bytes lost\n",
         mwNmlNumAlloc+mwNumCurAlloc-count, mwNmlCurAlloc+mwStatCurAlloc-size );
        return 0;
        }

    return 1;
    }

/*
**  If mwData* is NULL:
**      Returns 0 if heap chain is broken.
**      Returns 1 if heap chain is intact.
**  If mwData* is not NULL:
**      Returns 0 if mwData* is missing or if chain is broken.
**      Returns 1 if chain is intact and mwData* is found.
*/
static int mwIsHeapOK( mwData *includes_mw ) {
    int found = 0;
    mwData *mw;

    for( mw = mwHead; mw; mw=mw->next ) {
        if( includes_mw == mw ) found++;
        if( !mwIsSafeAddr( mw, mwDataSize ) ) return 0;
        if( mw->prev ) {
            if( !mwIsSafeAddr( mw->prev, mwDataSize ) ) return 0;
            if( mw==mwHead || mw->prev->next != mw ) return 0;
            }
        if( mw->next ) {
            if( !mwIsSafeAddr( mw->next, mwDataSize ) ) return 0;
            if( mw==mwTail || mw->next->prev != mw ) return 0;
            }
        else if( mw!=mwTail ) return 0;
        }

    if( includes_mw != NULL && !found ) return 0;

    return 1;
    }

static int mwIsOwned( mwData* mw, const char *file, int line ) {
    int retv;
    mwStat *ms;

    /* see if the address is legal according to OS */
    if( !mwIsSafeAddr( mw, mwDataSize ) ) return 0;

    /* make sure we have _anything_ allocated */
    if( mwHead == NULL && mwTail == NULL && mwStatCurAlloc == 0 )
        return 0;

    /* calculate checksum */
    if( mw->check != CHKVAL(mw) ) {
        /* may be damaged checksum, see if block is in heap */
        if( mwIsHeapOK( mw ) ) {
            /* damaged checksum, repair it */
            mwWrite( "internal: <%ld> %s(%d), checksum for MW-%p is incorrect\n",
                mwCounter, file, line, mw );
            mwIncErr();
            if( mwIsReadAddr( mw->file, 1 ) ) {
                ms = mwStatGet( mw->file, -1, 0 );
                if( ms == NULL ) mw->file = "<relinked>";
                }
            else mw->file = "<unknown>";
            mw->size = 0;
            mw->check = CHKVAL(mw);
            return 1;
            }
        /* no, it's just some garbage data */
        return 0;
        }

   /* check that the non-NULL pointers are safe */
   if( mw->prev && !mwIsSafeAddr( mw->prev, mwDataSize ) ) mwRelink( mw, file, line );
   if( mw->next && !mwIsSafeAddr( mw->next, mwDataSize ) ) mwRelink( mw, file, line );

    /* safe address, checksum OK, proceed with heap checks */

    /* see if the block is in the heap */
    retv = 0;
    if( mw->prev ) { if( mw->prev->next == mw ) retv ++; }
    else { if( mwHead == mw ) retv++; }
    if( mw->next ) { if( mw->next->prev == mw ) retv ++; }
    else { if( mwTail == mw ) retv++; }
    if( mw->check == CHKVAL(mw) ) retv ++;
    if( retv > 2 ) return 1;

    /* block not in heap, check heap for corruption */

    if( !mwIsHeapOK( mw ) ) {
        if( mwRelink( mw, file, line ) )
            return 1;
        }

    /* unable to repair */
    mwWrite( "internal: <%ld> %s(%d), mwIsOwned fails for MW-%p\n",
       mwCounter, file, line, mw );
    mwIncErr();

    return 0;
    }

/*
** mwTestBuf:
**  Checks a buffers links and pre/postfixes.
**  Writes errors found to the log.
**  Returns zero if no errors found.
*/
static int mwTestBuf( mwData* mw, const char* file, int line ) {
    int retv = 0;
    char *p;

    if( file == NULL ) file = "unknown";

    if( !mwIsSafeAddr( mw, mwDataSize + mwOverflowZoneSize ) ) {
        mwWrite( "internal: <%ld> %s(%d): pointer MW-%p is invalid\n",
            mwCounter, file, line, mw );
        mwIncErr();
        return 2;
        }

    if( mw->check != CHKVAL(mw) ) {
        mwWrite( "internal: <%ld> %s(%d), info trashed; relinking\n",
            mwCounter, file, line );
        mwIncErr();
        if( !mwRelink( mw, file, line ) ) return 2;
        }

    if( mw->prev && mw->prev->next != mw ) {
        mwWrite( "internal: <%ld> %s(%d), buffer <%ld> %s(%d) link1 broken\n",
            mwCounter,file,line, (long)mw->size, mw->count, mw->file, mw->line );
        mwIncErr();
        if( !mwRelink( mw, file, line ) ) retv = 2;
        }
    if( mw->next && mw->next->prev != mw ) {
        mwWrite( "internal: <%ld> %s(%d), buffer <%ld> %s(%d) link2 broken\n",
            mwCounter,file,line, (long)mw->size, mw->count, mw->file, mw->line );
        mwIncErr();
        if( !mwRelink( mw, file, line ) ) retv = 2;
        }

    p = ((char*)mw) + mwDataSize;
    if( mwCheckOF( p ) ) {
        mwWrite( "underflow: <%ld> %s(%d), %ld bytes alloc'd at <%ld> %s(%d)\n",
            mwCounter,file,line, (long)mw->size, mw->count, mw->file, mw->line );
        mwIncErr();
        retv = 1;
        }
    p += mwOverflowZoneSize + mw->size;
    if( mwIsReadAddr( p, mwOverflowZoneSize ) && mwCheckOF( p ) ) {
        mwWrite( "overflow: <%ld> %s(%d), %ld bytes alloc'd at <%ld> %s(%d)\n",
            mwCounter,file,line, (long)mw->size, mw->count, mw->file, mw->line );
        mwIncErr();
        retv = 1;
        }

    return retv;
    }

static void mwDefaultOutFunc( int c ) {
    if( mwLogR() ) fputc( c, mwLogR() );
    }

static void mwWrite( const char *format, ... ) {
    int tot, oflow = 0;
    va_list mark;
    mwAutoInit();
    if( mwOutFunction == NULL ) mwOutFunction = mwDefaultOutFunc;
    va_start( mark, format );
    tot = vsprintf( mwPrintBuf, format, mark );
    va_end( mark );
    if( tot >= MW_TRACE_BUFFER ) { mwPrintBuf[MW_TRACE_BUFFER] = 0; oflow = 1; }
    for(tot=0;mwPrintBuf[tot];tot++)
        (*mwOutFunction)( mwPrintBuf[tot] );
    if( oflow ) {
        mwWrite( "\ninternal: mwWrite(): WARNING! OUTPUT EXCEEDED %u CHARS: SYSTEM UNSTABLE\n", MW_TRACE_BUFFER-1 );
        FLUSH();
        }
    return;
    }

static void mwLogFile( const char *name ) {
   time_t tid;
   (void) time( &tid );
   if( mwLogR() != NULL ) {
      fclose( mwLogR() );
      mwLogW( NULL );
   }
   if( name == NULL ) {
      return;
   }   
    mwLogW( fopen( name, "a" COMMIT ) );
    if( mwLogR() == NULL ){
        mwWrite( "logfile: failed to open/create file '%s'\n", name );
    }   
}

/*
** Try to free NML memory until a contiguous allocation of
** 'needed' bytes can be satisfied. If this is not enough
** and the 'urgent' parameter is nonzero, grabbed memory is
** also freed.
*/
static size_t mwFreeUp( size_t needed, int urgent ) {
    void *p;
    mwData *mw, *mw2;
    char *data;

    /* free grabbed NML memory */
    for(;;) {
        if( mwDrop_( 1, MW_VAL_NML, 1 ) == 0 ) break;
        p = malloc( needed );
        if( p == NULL ) continue;
        free( p );
        return needed;
        }

    /* free normal NML memory */
    mw = mwHead;
    while( mw != NULL ) {
        if( !(mw->flag & MW_NML) ) mw = mw->next;
        else {
            data = ((char*)mw)+mwDataSize+mwOverflowZoneSize;
            if( mwTestMem( data, mw->size, MW_VAL_NML ) ) {
                mwIncErr();
                mwWrite( "wild pointer: <%ld> NoMansLand %p alloc'd at %s(%d)\n",
                    mw->count, data + mwOverflowZoneSize, mw->file, mw->line );
                }
            mw2 = mw->next;
            mwUnlink( mw, "mwFreeUp", 0 );
            free( mw );
            mw = mw2;
            p = malloc( needed );
            if( p == NULL ) continue;
            free( p );
            return needed;
            }
        }

    /* if not urgent (for internal purposes), fail */
    if( !urgent ) return 0;

    /* free grabbed memory */
    for(;;) {
        if( mwDrop_( 1, MW_VAL_GRB, 1 ) == 0 ) break;
        p = malloc( needed );
        if( p == NULL ) continue;
        free( p );
        return needed;
        }

    return 0;
    }

static const void * mwTestMem( const void *p, unsigned len, int c ) {
    const unsigned char *ptr;
    ptr = (const unsigned char *) p;
    while( len-- ) {
        if( *ptr != (unsigned char)c ) return (const void*)ptr;
        ptr ++;
        }
    return NULL;
    }

static int mwStrCmpI( const char *s1, const char *s2 ) {
    if( s1 == NULL || s2 == NULL ) return 0;
    while( *s1 ) {
        if( toupper(*s2) == toupper(*s1) ) { s1++; s2++; continue; }
        return 1;
        }
    return 0;
    }

#define AIPH() if( always_invoked ) { mwWrite("autocheck: <%ld> %s(%d) ", mwCounter, file, line ); always_invoked = 0; }

static int mwTestNow( const char *file, int line, int always_invoked ) {
    int retv = 0;
    mwData *mw;
    char *data;

    if( file && !always_invoked )
        mwWrite("check: <%ld> %s(%d), checking %s%s%s\n",
            mwCounter, file, line,
         (mwTestFlags & MW_TEST_CHAIN) ? "chain ": "",
          (mwTestFlags & MW_TEST_ALLOC) ? "alloc ": "",
          (mwTestFlags & MW_TEST_NML) ? "nomansland ": ""
         );

    if( mwTestFlags & MW_TEST_CHAIN ) {
        for( mw = mwHead; mw; mw=mw->next ) {
         if( !mwIsSafeAddr(mw, mwDataSize) ) {
            AIPH();
            mwWrite("check: heap corruption detected\n");
            mwIncErr();
            return retv + 1;
            }
         if( mw->prev ) {
            if( !mwIsSafeAddr(mw->prev, mwDataSize) ) {
               AIPH();
               mwWrite("check: heap corruption detected\n");
               mwIncErr();
               return retv + 1;
               }
            if( mw==mwHead || mw->prev->next != mw ) {
               AIPH();
               mwWrite("check: heap chain broken, prev link incorrect\n");
               mwIncErr();
               retv ++;
               }
            }
         if( mw->next ) {
            if( !mwIsSafeAddr(mw->next, mwDataSize) ) {
               AIPH();
               mwWrite("check: heap corruption detected\n");
               mwIncErr();
               return retv + 1;
               }
            if( mw==mwTail || mw->next->prev != mw ) {
               AIPH();
               mwWrite("check: heap chain broken, next link incorrect\n");
               mwIncErr();
               retv ++;
               }
            }
         else if( mw!=mwTail ) {
            AIPH();
            mwWrite("check: heap chain broken, tail incorrect\n");
            mwIncErr();
            retv ++;
            }
            }
        }
    if( mwTestFlags & MW_TEST_ALLOC ) {
        for( mw = mwHead; mw; mw=mw->next ) {
            if( mwTestBuf( mw, file, line ) ) retv ++;
            }
        }
    if( mwTestFlags & MW_TEST_NML ) {
        for( mw = mwHead; mw; mw=mw->next ) {
            if( (mw->flag & MW_NML) ) {
                data = ((char*)mw)+mwDataSize+mwOverflowZoneSize;
                if( mwTestMem( data, mw->size, MW_VAL_NML ) ) {
                    mwIncErr();
                    mwWrite( "wild pointer: <%ld> NoMansLand %p alloc'd at %s(%d)\n",
                        mw->count, data + mwOverflowZoneSize, mw->file, mw->line );
                    }
                }
            }
        }


   if( file && !always_invoked && !retv )
        mwWrite("check: <%ld> %s(%d), complete; no errors\n",
            mwCounter, file, line );
    return retv;
    }

/**********************************************************************
** Statistics
**********************************************************************/

static void mwStatReport()
{
    mwStat* ms, *ms2;
    const char *modname;
    int modnamelen;

    /* global statistics report */
    mwWrite( "\nMemory usage statistics (global):\n" );
    mwWrite( " N)umber of allocations made: %ld\n", mwStatNumAlloc );
    mwWrite( " L)argest memory usage      : %ld\n", mwStatMaxAlloc );
    mwWrite( " T)otal of all alloc() calls: %ld\n", mwStatTotAlloc );
    mwWrite( " U)nfreed bytes totals      : %ld\n", mwStatCurAlloc );
    FLUSH();

    if( mwStatLevel < 1 ) return;

    /* on a per-module basis */
    mwWrite( "\nMemory usage statistics (detailed):\n");
    mwWrite( " Module/Line                                Number   Largest  Total    Unfreed \n");
    for( ms=mwStatList; ms; ms=ms->next )
    {
        if( ms->line == -1 )
        {
         if( ms->file == NULL || !mwIsReadAddr(ms->file,22) ) modname = "<unknown>";
         else modname = ms->file;
         modnamelen = strlen(modname);
         if( modnamelen > 42 )
         {
            modname = modname + modnamelen - 42;
         }

            mwWrite(" %-42s %-8ld %-8ld %-8ld %-8ld\n",
               modname, ms->num, ms->max, ms->total, ms->curr );
            if( ms->file && mwStatLevel > 1 )
            {
                for( ms2=mwStatList; ms2; ms2=ms2->next )
                {
                    if( ms2->line!=-1 && ms2->file!=NULL && !mwStrCmpI( ms2->file, ms->file ) )
               {
               mwWrite( "  %-8d                                  %-8ld %-8ld %-8ld %-8ld\n",
                  ms2->line, ms2->num, ms2->max, ms2->total, ms2->curr );
               }
            }
         }
      }
   }
}

static mwStat* mwStatGet( const char *file, int line, int makenew ) {
    mwStat* ms;

    if( mwStatLevel < 2 ) line = -1;

    for( ms=mwStatList; ms!=NULL; ms=ms->next ) {
        if( line != ms->line ) continue;
        if( file==NULL ) {
            if( ms->file == NULL ) break;
            continue;
            }
        if( ms->file == NULL ) continue;
        if( !strcmp( ms->file, file ) ) break;
        }

    if( ms != NULL ) return ms;

    if( !makenew ) return NULL;

    ms = (mwStat*) malloc( sizeof(mwStat) );
    if( ms == NULL ) {
        if( mwFreeUp( sizeof(mwStat), 0 ) < sizeof(mwStat) ||
            (ms=(mwStat*)malloc(sizeof(mwStat))) == NULL ) {
            mwWrite("internal: memory low, statistics incomplete for '%s'\n", file );
            return NULL;
            }
        }
    ms->file = file;
    ms->line = line;
    ms->total = 0L;
    ms->max = 0L;
    ms->num = 0L;
    ms->curr = 0L;
    ms->next = mwStatList;
    mwStatList = ms;
    return ms;
    }

static void mwStatAlloc( size_t size, const char* file, int line ) {
    mwStat* ms;

    /* update the module statistics */
    ms = mwStatGet( file, -1, 1 );
    if( ms != NULL ) {
        ms->total += (long) size;
        ms->curr += (long) size;
        ms->num ++;
        if( ms->curr > ms->max ) ms->max = ms->curr;
        }

    /* update the line statistics */
    if( mwStatLevel > 1 && line != -1 && file ) {
        ms = mwStatGet( file, line, 1 );
        if( ms != NULL ) {
            ms->total += (long) size;
            ms->curr += (long) size;
            ms->num ++;
            if( ms->curr > ms->max ) ms->max = ms->curr;
            }
        }

    }

static void mwStatFree( size_t size, const char* file, int line ) {
    mwStat* ms;

    /* update the module statistics */
    ms = mwStatGet( file, -1, 1 );
    if( ms != NULL ) ms->curr -= (long) size;

    /* update the line statistics */
    if( mwStatLevel > 1 && line != -1 && file ) {
        ms = mwStatGet( file, line, 1 );
        if( ms != NULL ) ms->curr -= (long) size;
        }
    }

/***********************************************************************
** Safe memory checkers
**
** Using ifdefs, implement the operating-system specific mechanism
** of identifying a piece of memory as legal to access with read
** and write priviliges. Default: return nonzero for non-NULL pointers.
***********************************************************************/

static char mwDummy( char c )
{
   return c;
}

#ifndef MW_SAFEADDR
#ifdef WIN32
#define MW_SAFEADDR
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
int mwIsReadAddr( const void *p, unsigned len )
{
    if( p == NULL ) return 0;
    if( IsBadReadPtr(p,len) ) return 0;
    return 1;
}
int mwIsSafeAddr( void *p, unsigned len )
{
    /* NOTE: For some reason, under Win95 the IsBad... */
    /* can return false for invalid pointers. */
    if( p == NULL ) return 0;
    if( IsBadReadPtr(p,len) || IsBadWritePtr(p,len) ) return 0;
    return 1;
}
#endif /* WIN32 */
#endif /* MW_SAFEADDR */

#ifndef MW_SAFEADDR
#ifdef SIGSEGV
#define MW_SAFEADDR

typedef void (*mwSignalHandlerPtr)( int );
mwSignalHandlerPtr mwOldSIGSEGV = (mwSignalHandlerPtr) 0;
jmp_buf mwSIGSEGVjump;
static void mwSIGSEGV( int n );

static void mwSIGSEGV( int n )
{
   n = n;
   longjmp( mwSIGSEGVjump, 1 );
}

int mwIsReadAddr( const void *p, unsigned len )
{
   const char *ptr;

    if( p == NULL ) return 0;
   if( !len ) return 1;

   /* set up to catch the SIGSEGV signal */
   mwOldSIGSEGV = signal( SIGSEGV, mwSIGSEGV );

   if( setjmp( mwSIGSEGVjump ) )
   {
      signal( SIGSEGV, mwOldSIGSEGV );
      return 0;
   }

   /* read all the bytes in the range */
   ptr = (const char *)p;
   ptr += len;

   /* the reason for this rather strange construct is that */
   /* we want to keep the number of used parameters and locals */
   /* to a minimum. if we use len for a counter gcc will complain */
   /* it may get clobbered by longjmp() at high warning levels. */
   /* it's a harmless warning, but this way we don't have to see it. */
   do
   {
      ptr --;
      if( *ptr == 0x7C ) (void) mwDummy( (char)0 );
   } while( (const void*) ptr != p );

   /* remove the handler */
   signal( SIGSEGV, mwOldSIGSEGV );

    return 1;
}
int mwIsSafeAddr( void *p, unsigned len )
{
   char *ptr;

   if( p == NULL ) return 0;
   if( !len ) return 1;

   /* set up to catch the SIGSEGV signal */
   mwOldSIGSEGV = signal( SIGSEGV, mwSIGSEGV );

   if( setjmp( mwSIGSEGVjump ) )
   {
      signal( SIGSEGV, mwOldSIGSEGV );
      return 0;
   }

   /* read and write-back all the bytes in the range */
   ptr = (char *)p;
   ptr += len;

   /* the reason for this rather strange construct is that */
   /* we want to keep the number of used parameters and locals */
   /* to a minimum. if we use len for a counter gcc will complain */
   /* it may get clobbered by longjmp() at high warning levels. */
   /* it's a harmless warning, but this way we don't have to see it. */
   do
   {
      ptr --;
      *ptr = mwDummy( *ptr );
   } while( (void*) ptr != p );

   /* remove the handler */
   signal( SIGSEGV, mwOldSIGSEGV );

    return 1;
}
#endif /* SIGSEGV */
#endif /* MW_SAFEADDR */

#ifndef MW_SAFEADDR
int mwIsReadAddr( const void *p, unsigned len )
{
    if( p == NULL ) return 0;
    if( len == 0 ) return 1;
    return 1;
}
int mwIsSafeAddr( void *p, unsigned len )
{
    if( p == NULL ) return 0;
    if( len == 0 ) return 1;
    return 1;
}
#endif

/**********************************************************************
** Mutex handling
**********************************************************************/

#if defined(WIN32) || defined(__WIN32__)

static void mwMutexInit( void )
{
   mwGlobalMutex = CreateMutex( NULL, FALSE, NULL);
   return;
}

static void mwMutexTerm( void )
{
   CloseHandle( mwGlobalMutex );
   return;
}

static void mwMutexLock( void )
{
   if( WaitForSingleObject(mwGlobalMutex, 1000 ) == WAIT_TIMEOUT )
   {
      mwWrite( "mwMutexLock: timed out, possible deadlock\n" );
   }
   return;
}

static void mwMutexUnlock( void )
{
   ReleaseMutex( mwGlobalMutex );
   return;
}

#endif

#if defined(MW_PTHREADS) || defined(HAVE_PTHREAD_H)

static void mwMutexInit( void )
{
   pthread_mutex_init( &mwGlobalMutex, NULL );
   return;
}

static void mwMutexTerm( void )
{
   pthread_mutex_destroy( &mwGlobalMutex );
   return;
}

static void mwMutexLock( void )
{
   pthread_mutex_lock(&mwGlobalMutex);
   return;
}

static void mwMutexUnlock( void )
{
   pthread_mutex_unlock(&mwGlobalMutex);
   return;
}

#endif

/**********************************************************************
** C++ new & delete
**********************************************************************/

#if 0 /* 980317: disabled C++ */

#ifdef __cplusplus
#ifndef MEMWATCH_NOCPP

int mwNCur = 0;
const char *mwNFile = NULL;
int mwNLine = 0;

class MemWatch {
public:
    MemWatch();
    ~MemWatch();
    };

MemWatch::MemWatch() {
    if( mwInited ) return;
    mwUseAtexit = 0;
    mwInit();
    }

MemWatch::~MemWatch() {
    if( mwUseAtexit ) return;
    mwTerm();
    }

/*
** This global new will catch all 'new' calls where MEMWATCH is
** not active.
*/
void* operator new( unsigned size ) {
    mwNCur = 0;
    return mwMalloc( size, "<unknown>", 0 );
    }

/*
** This is the new operator that's called when a module uses mwNew.
*/
void* operator new( unsigned size, const char *file, int line ) {
    mwNCur = 0;
    return mwMalloc( size, file, line );
    }

/*
** This is the new operator that's called when a module uses mwNew[].
** -- hjc 07/16/02
*/
void* operator new[] ( unsigned size, const char *file, int line ) {
    mwNCur = 0;
    return mwMalloc( size, file, line );
    }

/*
** Since this delete operator will recieve ALL delete's
** even those from within libraries, we must accept
** delete's before we've been initialized. Nor can we
** reliably check for wild free's if the mwNCur variable
** is not set.
*/
void operator delete( void *p ) {
    if( p == NULL ) return;
    if( !mwInited ) {
        free( p );
        return;
        }
    if( mwNCur ) {
        mwFree( p, mwNFile, mwNLine );
        mwNCur = 0;
        return;
        }
    mwFree_( p );
    }

void operator delete[]( void *p ) {
    if( p == NULL ) return;
    if( !mwInited ) {
        free( p );
        return;
        }
    if( mwNCur ) {
        mwFree( p, mwNFile, mwNLine );
        mwNCur = 0;
        return;
        }
    mwFree_( p );
    }

#endif /* MEMWATCH_NOCPP */
#endif /* __cplusplus */

#endif /* 980317: disabled C++ */

#endif /* MEMWATCH */
    
/* MEMWATCH.C */

---