tcl/generic/tclCkalloc.c

/*
 * tclCkalloc.c --
 *
 *    Interface to malloc and free that provides support for debugging problems
 *    involving overwritten, double freeing memory and loss of memory.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 Sun Microsystems, Inc.
 * Copyright (c) 1998-1999 by Scriptics Corporation.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * This code contributed by Karl Lehenbauer and Mark Diekhans
 *
 * RCS: @(#) $Id: tclCkalloc.c,v 1.19 2003/01/19 07:21:18 hobbs Exp $
 */

#include "tclInt.h"
#include "tclPort.h"

#define FALSE	0
#define TRUE	1

#ifdef TCL_MEM_DEBUG

/*
 * One of the following structures is allocated each time the
 * "memory tag" command is invoked, to hold the current tag.
 */

typedef struct MemTag {
    int refCount;		/* Number of mem_headers referencing
				 * this tag. */
    char string[4];		/* Actual size of string will be as
				 * large as needed for actual tag.  This
				 * must be the last field in the structure. */
} MemTag;

#define TAG_SIZE(bytesInString) ((unsigned) sizeof(MemTag) + bytesInString - 3)

static MemTag *curTagPtr = NULL;/* Tag to use in all future mem_headers
				 * (set by "memory tag" command). */

/*
 * One of the following structures is allocated just before each
 * dynamically allocated chunk of memory, both to record information
 * about the chunk and to help detect chunk under-runs.
 */

#define LOW_GUARD_SIZE (8 + (32 - (sizeof(long) + sizeof(int)))%8)
struct mem_header {
    struct mem_header *flink;
    struct mem_header *blink;
    MemTag *tagPtr;		/* Tag from "memory tag" command;  may be
				 * NULL. */
    CONST char *file;
    long length;
    int line;
    unsigned char low_guard[LOW_GUARD_SIZE];
				/* Aligns body on 8-byte boundary, plus
				 * provides at least 8 additional guard bytes
				 * to detect underruns. */
    char body[1];		/* First byte of client's space.  Actual
				 * size of this field will be larger than
				 * one. */
};

static struct mem_header *allocHead = NULL;  /* List of allocated structures */

#define GUARD_VALUE  0141

/*
 * The following macro determines the amount of guard space *above* each
 * chunk of memory.
 */

#define HIGH_GUARD_SIZE 8

/*
 * The following macro computes the offset of the "body" field within
 * mem_header.  It is used to get back to the header pointer from the
 * body pointer that's used by clients.
 */

#define BODY_OFFSET \
	((unsigned long) (&((struct mem_header *) 0)->body))

static int total_mallocs = 0;
static int total_frees = 0;
static int current_bytes_malloced = 0;
static int maximum_bytes_malloced = 0;
static int current_malloc_packets = 0;
static int maximum_malloc_packets = 0;
static int break_on_malloc = 0;
static int trace_on_at_malloc = 0;
static int  alloc_tracing = FALSE;
static int  init_malloced_bodies = TRUE;
#ifdef MEM_VALIDATE
    static int  validate_memory = TRUE;
#else
    static int  validate_memory = FALSE;
#endif

/*
 * The following variable indicates to TclFinalizeMemorySubsystem()
 * that it should dump out the state of memory before exiting.  If the
 * value is non-NULL, it gives the name of the file in which to
 * dump memory usage information.
 */

char *tclMemDumpFileName = NULL;

static char *onExitMemDumpFileName = NULL;
static char dumpFile[100];	/* Records where to dump memory allocation
				 * information. */

/*
 * Mutex to serialize allocations.  This is a low-level mutex that must
 * be explicitly initialized.  This is necessary because the self
 * initializing mutexes use ckalloc...
 */
static Tcl_Mutex *ckallocMutexPtr;
static int ckallocInit = 0;

/*
 * Prototypes for procedures defined in this file:
 */

static int		CheckmemCmd _ANSI_ARGS_((ClientData clientData,
			    Tcl_Interp *interp, int argc, CONST char *argv[]));
static int		MemoryCmd _ANSI_ARGS_((ClientData clientData,
			    Tcl_Interp *interp, int argc, CONST char **argv));
static void		ValidateMemory _ANSI_ARGS_((
			    struct mem_header *memHeaderP, CONST char *file,
			    int line, int nukeGuards));

/*
 *----------------------------------------------------------------------
 *
 * TclInitDbCkalloc --
 *	Initialize the locks used by the allocator.
 *	This is only appropriate to call in a single threaded environment,
 *	such as during TclInitSubsystems.
 *
 *----------------------------------------------------------------------
 */
void
TclInitDbCkalloc()
{
    if (!ckallocInit) {
	ckallocInit = 1;
	ckallocMutexPtr = Tcl_GetAllocMutex();
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TclDumpMemoryInfo --
 *     Display the global memory management statistics.
 *
 *----------------------------------------------------------------------
 */
void
TclDumpMemoryInfo(outFile)
    FILE *outFile;
{
    fprintf(outFile,"total mallocs             %10d\n",
	    total_mallocs);
    fprintf(outFile,"total frees               %10d\n",
	    total_frees);
    fprintf(outFile,"current packets allocated %10d\n",
	    current_malloc_packets);
    fprintf(outFile,"current bytes allocated   %10d\n",
	    current_bytes_malloced);
    fprintf(outFile,"maximum packets allocated %10d\n",
	    maximum_malloc_packets);
    fprintf(outFile,"maximum bytes allocated   %10d\n",
	    maximum_bytes_malloced);
}


/*
 *----------------------------------------------------------------------
 *
 * ValidateMemory --
 *
 *	Validate memory guard zones for a particular chunk of allocated
 *	memory.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Prints validation information about the allocated memory to stderr.
 *
 *----------------------------------------------------------------------
 */

static void
ValidateMemory(memHeaderP, file, line, nukeGuards)
    struct mem_header *memHeaderP;	/* Memory chunk to validate */
    CONST char        *file;		/* File containing the call to
					 * Tcl_ValidateAllMemory */
    int                line;		/* Line number of call to
					 * Tcl_ValidateAllMemory */
    int                nukeGuards;	/* If non-zero, indicates that the
					 * memory guards are to be reset to 0
					 * after they have been printed */
{
    unsigned char *hiPtr;
    int   idx;
    int   guard_failed = FALSE;
    int byte;

    for (idx = 0; idx < LOW_GUARD_SIZE; idx++) {
        byte = *(memHeaderP->low_guard + idx);
        if (byte != GUARD_VALUE) {
            guard_failed = TRUE;
            fflush(stdout);
	    byte &= 0xff;
            fprintf(stderr, "low guard byte %d is 0x%x  \t%c\n", idx, byte,
		    (isprint(UCHAR(byte)) ? byte : ' ')); /* INTL: bytes */
        }
    }
    if (guard_failed) {
        TclDumpMemoryInfo (stderr);
        fprintf(stderr, "low guard failed at %lx, %s %d\n",
                 (long unsigned int) memHeaderP->body, file, line);
        fflush(stderr);  /* In case name pointer is bad. */
        fprintf(stderr, "%ld bytes allocated at (%s %d)\n", memHeaderP->length,
		memHeaderP->file, memHeaderP->line);
        panic ("Memory validation failure");
    }

    hiPtr = (unsigned char *)memHeaderP->body + memHeaderP->length;
    for (idx = 0; idx < HIGH_GUARD_SIZE; idx++) {
        byte = *(hiPtr + idx);
        if (byte != GUARD_VALUE) {
            guard_failed = TRUE;
            fflush (stdout);
	    byte &= 0xff;
            fprintf(stderr, "hi guard byte %d is 0x%x  \t%c\n", idx, byte,
		    (isprint(UCHAR(byte)) ? byte : ' ')); /* INTL: bytes */
        }
    }

    if (guard_failed) {
        TclDumpMemoryInfo (stderr);
        fprintf(stderr, "high guard failed at %lx, %s %d\n",
                 (long unsigned int) memHeaderP->body, file, line);
        fflush(stderr);  /* In case name pointer is bad. */
        fprintf(stderr, "%ld bytes allocated at (%s %d)\n",
		memHeaderP->length, memHeaderP->file,
		memHeaderP->line);
        panic("Memory validation failure");
    }

    if (nukeGuards) {
        memset ((char *) memHeaderP->low_guard, 0, LOW_GUARD_SIZE);
        memset ((char *) hiPtr, 0, HIGH_GUARD_SIZE);
    }

}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_ValidateAllMemory --
 *
 *	Validate memory guard regions for all allocated memory.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Displays memory validation information to stderr.
 *
 *----------------------------------------------------------------------
 */
void
Tcl_ValidateAllMemory (file, line)
    CONST char  *file;	/* File from which Tcl_ValidateAllMemory was called */
    int          line;	/* Line number of call to Tcl_ValidateAllMemory */
{
    struct mem_header *memScanP;

    if (!ckallocInit) {
	TclInitDbCkalloc();
    }
    Tcl_MutexLock(ckallocMutexPtr);
    for (memScanP = allocHead; memScanP != NULL; memScanP = memScanP->flink) {
        ValidateMemory(memScanP, file, line, FALSE);
    }
    Tcl_MutexUnlock(ckallocMutexPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DumpActiveMemory --
 *
 *	Displays all allocated memory to a file; if no filename is given,
 *	information will be written to stderr.
 *
 * Results:
 *	Return TCL_ERROR if an error accessing the file occurs, `errno'
 *	will have the file error number left in it.
 *----------------------------------------------------------------------
 */
int
Tcl_DumpActiveMemory (fileName)
    CONST char *fileName;		/* Name of the file to write info to */
{
    FILE              *fileP;
    struct mem_header *memScanP;
    char              *address;

    if (fileName == NULL) {
	fileP = stderr;
    } else {
	fileP = fopen(fileName, "w");
	if (fileP == NULL) {
	    return TCL_ERROR;
	}
    }

    Tcl_MutexLock(ckallocMutexPtr);
    for (memScanP = allocHead; memScanP != NULL; memScanP = memScanP->flink) {
        address = &memScanP->body [0];
        fprintf(fileP, "%8lx - %8lx  %7ld @ %s %d %s",
		(long unsigned int) address,
                 (long unsigned int) address + memScanP->length - 1,
		 memScanP->length, memScanP->file, memScanP->line,
		 (memScanP->tagPtr == NULL) ? "" : memScanP->tagPtr->string);
	(void) fputc('\n', fileP);
    }
    Tcl_MutexUnlock(ckallocMutexPtr);

    if (fileP != stderr) {
	fclose (fileP);
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DbCkalloc - debugging ckalloc
 *
 *        Allocate the requested amount of space plus some extra for
 *        guard bands at both ends of the request, plus a size, panicing
 *        if there isn't enough space, then write in the guard bands
 *        and return the address of the space in the middle that the
 *        user asked for.
 *
 *        The second and third arguments are file and line, these contain
 *        the filename and line number corresponding to the caller.
 *        These are sent by the ckalloc macro; it uses the preprocessor
 *        autodefines __FILE__ and __LINE__.
 *
 *----------------------------------------------------------------------
 */
char *
Tcl_DbCkalloc(size, file, line)
    unsigned int size;
    CONST char  *file;
    int          line;
{
    struct mem_header *result = NULL;

    if (validate_memory)
        Tcl_ValidateAllMemory (file, line);


    /* Don't let size argument to TclpAlloc overflow */
    if (size <= UINT_MAX - HIGH_GUARD_SIZE - sizeof(struct mem_header)) {
	result = (struct mem_header *) TclpAlloc((unsigned)size +
		sizeof(struct mem_header) + HIGH_GUARD_SIZE);
    }
    if (result == NULL) {
        fflush(stdout);
        TclDumpMemoryInfo(stderr);
        panic("unable to alloc %u bytes, %s line %d", size, file, line);
    }

    /*
     * Fill in guard zones and size.  Also initialize the contents of
     * the block with bogus bytes to detect uses of initialized data.
     * Link into allocated list.
     */
    if (init_malloced_bodies) {
        memset ((VOID *) result, GUARD_VALUE,
		size + sizeof(struct mem_header) + HIGH_GUARD_SIZE);
    } else {
	memset ((char *) result->low_guard, GUARD_VALUE, LOW_GUARD_SIZE);
	memset (result->body + size, GUARD_VALUE, HIGH_GUARD_SIZE);
    }
    if (!ckallocInit) {
	TclInitDbCkalloc();
    }
    Tcl_MutexLock(ckallocMutexPtr);
    result->length = size;
    result->tagPtr = curTagPtr;
    if (curTagPtr != NULL) {
	curTagPtr->refCount++;
    }
    result->file = file;
    result->line = line;
    result->flink = allocHead;
    result->blink = NULL;

    if (allocHead != NULL)
        allocHead->blink = result;
    allocHead = result;

    total_mallocs++;
    if (trace_on_at_malloc && (total_mallocs >= trace_on_at_malloc)) {
        (void) fflush(stdout);
        fprintf(stderr, "reached malloc trace enable point (%d)\n",
                total_mallocs);
        fflush(stderr);
        alloc_tracing = TRUE;
        trace_on_at_malloc = 0;
    }

    if (alloc_tracing)
        fprintf(stderr,"ckalloc %lx %u %s %d\n",
		(long unsigned int) result->body, size, file, line);

    if (break_on_malloc && (total_mallocs >= break_on_malloc)) {
        break_on_malloc = 0;
        (void) fflush(stdout);
        fprintf(stderr,"reached malloc break limit (%d)\n",
                total_mallocs);
        fprintf(stderr, "program will now enter C debugger\n");
        (void) fflush(stderr);
	abort();
    }

    current_malloc_packets++;
    if (current_malloc_packets > maximum_malloc_packets)
        maximum_malloc_packets = current_malloc_packets;
    current_bytes_malloced += size;
    if (current_bytes_malloced > maximum_bytes_malloced)
        maximum_bytes_malloced = current_bytes_malloced;

    Tcl_MutexUnlock(ckallocMutexPtr);

    return result->body;
}

char *
Tcl_AttemptDbCkalloc(size, file, line)
    unsigned int size;
    CONST char  *file;
    int          line;
{
    struct mem_header *result = NULL;

    if (validate_memory)
        Tcl_ValidateAllMemory (file, line);

    /* Don't let size argument to TclpAlloc overflow */
    if (size <= UINT_MAX - HIGH_GUARD_SIZE - sizeof(struct mem_header)) {
	result = (struct mem_header *) TclpAlloc((unsigned)size +
		sizeof(struct mem_header) + HIGH_GUARD_SIZE);
    }
    if (result == NULL) {
        fflush(stdout);
        TclDumpMemoryInfo(stderr);
	return NULL;
    }

    /*
     * Fill in guard zones and size.  Also initialize the contents of
     * the block with bogus bytes to detect uses of initialized data.
     * Link into allocated list.
     */
    if (init_malloced_bodies) {
        memset ((VOID *) result, GUARD_VALUE,
		size + sizeof(struct mem_header) + HIGH_GUARD_SIZE);
    } else {
	memset ((char *) result->low_guard, GUARD_VALUE, LOW_GUARD_SIZE);
	memset (result->body + size, GUARD_VALUE, HIGH_GUARD_SIZE);
    }
    if (!ckallocInit) {
	TclInitDbCkalloc();
    }
    Tcl_MutexLock(ckallocMutexPtr);
    result->length = size;
    result->tagPtr = curTagPtr;
    if (curTagPtr != NULL) {
	curTagPtr->refCount++;
    }
    result->file = file;
    result->line = line;
    result->flink = allocHead;
    result->blink = NULL;

    if (allocHead != NULL)
        allocHead->blink = result;
    allocHead = result;

    total_mallocs++;
    if (trace_on_at_malloc && (total_mallocs >= trace_on_at_malloc)) {
        (void) fflush(stdout);
        fprintf(stderr, "reached malloc trace enable point (%d)\n",
                total_mallocs);
        fflush(stderr);
        alloc_tracing = TRUE;
        trace_on_at_malloc = 0;
    }

    if (alloc_tracing)
        fprintf(stderr,"ckalloc %lx %u %s %d\n",
		(long unsigned int) result->body, size, file, line);

    if (break_on_malloc && (total_mallocs >= break_on_malloc)) {
        break_on_malloc = 0;
        (void) fflush(stdout);
        fprintf(stderr,"reached malloc break limit (%d)\n",
                total_mallocs);
        fprintf(stderr, "program will now enter C debugger\n");
        (void) fflush(stderr);
	abort();
    }

    current_malloc_packets++;
    if (current_malloc_packets > maximum_malloc_packets)
        maximum_malloc_packets = current_malloc_packets;
    current_bytes_malloced += size;
    if (current_bytes_malloced > maximum_bytes_malloced)
        maximum_bytes_malloced = current_bytes_malloced;

    Tcl_MutexUnlock(ckallocMutexPtr);

    return result->body;
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_DbCkfree - debugging ckfree
 *
 *        Verify that the low and high guards are intact, and if so
 *        then free the buffer else panic.
 *
 *        The guards are erased after being checked to catch duplicate
 *        frees.
 *
 *        The second and third arguments are file and line, these contain
 *        the filename and line number corresponding to the caller.
 *        These are sent by the ckfree macro; it uses the preprocessor
 *        autodefines __FILE__ and __LINE__.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_DbCkfree(ptr, file, line)
    char       *ptr;
    CONST char *file;
    int         line;
{
    struct mem_header *memp;

    if (ptr == NULL) {
	return 0;
    }

    /*
     * The following cast is *very* tricky.  Must convert the pointer
     * to an integer before doing arithmetic on it, because otherwise
     * the arithmetic will be done differently (and incorrectly) on
     * word-addressed machines such as Crays (will subtract only bytes,
     * even though BODY_OFFSET is in words on these machines).
     */

    memp = (struct mem_header *) (((unsigned long) ptr) - BODY_OFFSET);

    if (alloc_tracing) {
        fprintf(stderr, "ckfree %lx %ld %s %d\n",
		(long unsigned int) memp->body, memp->length, file, line);
    }

    if (validate_memory) {
        Tcl_ValidateAllMemory(file, line);
    }

    Tcl_MutexLock(ckallocMutexPtr);
    ValidateMemory(memp, file, line, TRUE);
    if (init_malloced_bodies) {
	memset((VOID *) ptr, GUARD_VALUE, (size_t) memp->length);
    }

    total_frees++;
    current_malloc_packets--;
    current_bytes_malloced -= memp->length;

    if (memp->tagPtr != NULL) {
	memp->tagPtr->refCount--;
	if ((memp->tagPtr->refCount == 0) && (curTagPtr != memp->tagPtr)) {
	    TclpFree((char *) memp->tagPtr);
	}
    }

    /*
     * Delink from allocated list
     */
    if (memp->flink != NULL)
        memp->flink->blink = memp->blink;
    if (memp->blink != NULL)
        memp->blink->flink = memp->flink;
    if (allocHead == memp)
        allocHead = memp->flink;
    TclpFree((char *) memp);
    Tcl_MutexUnlock(ckallocMutexPtr);

    return 0;
}

/*
 *--------------------------------------------------------------------
 *
 * Tcl_DbCkrealloc - debugging ckrealloc
 *
 *	Reallocate a chunk of memory by allocating a new one of the
 *	right size, copying the old data to the new location, and then
 *	freeing the old memory space, using all the memory checking
 *	features of this package.
 *
 *--------------------------------------------------------------------
 */
char *
Tcl_DbCkrealloc(ptr, size, file, line)
    char        *ptr;
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *new;
    unsigned int copySize;
    struct mem_header *memp;

    if (ptr == NULL) {
	return Tcl_DbCkalloc(size, file, line);
    }

    /*
     * See comment from Tcl_DbCkfree before you change the following
     * line.
     */

    memp = (struct mem_header *) (((unsigned long) ptr) - BODY_OFFSET);

    copySize = size;
    if (copySize > (unsigned int) memp->length) {
	copySize = memp->length;
    }
    new = Tcl_DbCkalloc(size, file, line);
    memcpy((VOID *) new, (VOID *) ptr, (size_t) copySize);
    Tcl_DbCkfree(ptr, file, line);
    return new;
}

char *
Tcl_AttemptDbCkrealloc(ptr, size, file, line)
    char        *ptr;
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *new;
    unsigned int copySize;
    struct mem_header *memp;

    if (ptr == NULL) {
	return Tcl_AttemptDbCkalloc(size, file, line);
    }

    /*
     * See comment from Tcl_DbCkfree before you change the following
     * line.
     */

    memp = (struct mem_header *) (((unsigned long) ptr) - BODY_OFFSET);

    copySize = size;
    if (copySize > (unsigned int) memp->length) {
	copySize = memp->length;
    }
    new = Tcl_AttemptDbCkalloc(size, file, line);
    if (new == NULL) {
	return NULL;
    }
    memcpy((VOID *) new, (VOID *) ptr, (size_t) copySize);
    Tcl_DbCkfree(ptr, file, line);
    return new;
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_Alloc, et al. --
 *
 *	These functions are defined in terms of the debugging versions
 *	when TCL_MEM_DEBUG is set.
 *
 * Results:
 *	Same as the debug versions.
 *
 * Side effects:
 *	Same as the debug versions.
 *
 *----------------------------------------------------------------------
 */

#undef Tcl_Alloc
#undef Tcl_Free
#undef Tcl_Realloc
#undef Tcl_AttemptAlloc
#undef Tcl_AttemptRealloc

char *
Tcl_Alloc(size)
    unsigned int size;
{
    return Tcl_DbCkalloc(size, "unknown", 0);
}

char *
Tcl_AttemptAlloc(size)
    unsigned int size;
{
    return Tcl_AttemptDbCkalloc(size, "unknown", 0);
}

void
Tcl_Free(ptr)
    char *ptr;
{
    Tcl_DbCkfree(ptr, "unknown", 0);
}

char *
Tcl_Realloc(ptr, size)
    char *ptr;
    unsigned int size;
{
    return Tcl_DbCkrealloc(ptr, size, "unknown", 0);
}
char *
Tcl_AttemptRealloc(ptr, size)
    char *ptr;
    unsigned int size;
{
    return Tcl_AttemptDbCkrealloc(ptr, size, "unknown", 0);
}

/*
 *----------------------------------------------------------------------
 *
 * MemoryCmd --
 *	Implements the Tcl "memory" command, which provides Tcl-level
 *	control of Tcl memory debugging information.
 *		memory active $file
 *		memory break_on_malloc $count
 *		memory info
 *		memory init on|off
 *		memory onexit $file
 *		memory tag $string
 *		memory trace on|off
 *		memory trace_on_at_malloc $count
 *		memory validate on|off
 *
 * Results:
 *     Standard TCL results.
 *
 *----------------------------------------------------------------------
 */
	/* ARGSUSED */
static int
MemoryCmd (clientData, interp, argc, argv)
    ClientData  clientData;
    Tcl_Interp *interp;
    int         argc;
    CONST char  **argv;
{
    CONST char *fileName;
    Tcl_DString buffer;
    int result;

    if (argc < 2) {
	Tcl_AppendResult(interp, "wrong # args: should be \"",
		argv[0], " option [args..]\"", (char *) NULL);
	return TCL_ERROR;
    }

    if ((strcmp(argv[1],"active") == 0) || (strcmp(argv[1],"display") == 0)) {
        if (argc != 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " ", argv[1], " file\"", (char *) NULL);
	    return TCL_ERROR;
	}
	fileName = Tcl_TranslateFileName(interp, argv[2], &buffer);
	if (fileName == NULL) {
	    return TCL_ERROR;
	}
	result = Tcl_DumpActiveMemory (fileName);
	Tcl_DStringFree(&buffer);
	if (result != TCL_OK) {
	    Tcl_AppendResult(interp, "error accessing ", argv[2],
		    (char *) NULL);
	    return TCL_ERROR;
	}
	return TCL_OK;
    }
    if (strcmp(argv[1],"break_on_malloc") == 0) {
        if (argc != 3) {
            goto argError;
	}
        if (Tcl_GetInt(interp, argv[2], &break_on_malloc) != TCL_OK) {
	    return TCL_ERROR;
	}
        return TCL_OK;
    }
    if (strcmp(argv[1],"info") == 0) {
	char buf[400];
	sprintf(buf, "%-25s %10d\n%-25s %10d\n%-25s %10d\n%-25s %10d\n%-25s %10d\n%-25s %10d\n",
	    "total mallocs", total_mallocs, "total frees", total_frees,
	    "current packets allocated", current_malloc_packets,
	    "current bytes allocated", current_bytes_malloced,
	    "maximum packets allocated", maximum_malloc_packets,
	    "maximum bytes allocated", maximum_bytes_malloced);
	Tcl_SetResult(interp, buf, TCL_VOLATILE);
        return TCL_OK;
    }
    if (strcmp(argv[1],"init") == 0) {
        if (argc != 3) {
            goto bad_suboption;
	}
        init_malloced_bodies = (strcmp(argv[2],"on") == 0);
        return TCL_OK;
    }
    if (strcmp(argv[1],"onexit") == 0) {
        if (argc != 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"",
		    argv[0], " onexit file\"", (char *) NULL);
	    return TCL_ERROR;
	}
	fileName = Tcl_TranslateFileName(interp, argv[2], &buffer);
	if (fileName == NULL) {
	    return TCL_ERROR;
	}
	onExitMemDumpFileName = dumpFile;
	strcpy(onExitMemDumpFileName,fileName);
	Tcl_DStringFree(&buffer);
	return TCL_OK;
    }
    if (strcmp(argv[1],"tag") == 0) {
	if (argc != 3) {
	    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		    " tag string\"", (char *) NULL);
	    return TCL_ERROR;
	}
	if ((curTagPtr != NULL) && (curTagPtr->refCount == 0)) {
	    TclpFree((char *) curTagPtr);
	}
	curTagPtr = (MemTag *) TclpAlloc(TAG_SIZE(strlen(argv[2])));
	curTagPtr->refCount = 0;
	strcpy(curTagPtr->string, argv[2]);
	return TCL_OK;
    }
    if (strcmp(argv[1],"trace") == 0) {
        if (argc != 3) {
            goto bad_suboption;
	}
        alloc_tracing = (strcmp(argv[2],"on") == 0);
        return TCL_OK;
    }

    if (strcmp(argv[1],"trace_on_at_malloc") == 0) {
        if (argc != 3) {
            goto argError;
	}
        if (Tcl_GetInt(interp, argv[2], &trace_on_at_malloc) != TCL_OK) {
	    return TCL_ERROR;
	}
	return TCL_OK;
    }
    if (strcmp(argv[1],"validate") == 0) {
        if (argc != 3) {
	    goto bad_suboption;
	}
        validate_memory = (strcmp(argv[2],"on") == 0);
        return TCL_OK;
    }

    Tcl_AppendResult(interp, "bad option \"", argv[1],
	    "\": should be active, break_on_malloc, info, init, onexit, ",
	    "tag, trace, trace_on_at_malloc, or validate", (char *) NULL);
    return TCL_ERROR;

argError:
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
	    " ", argv[1], " count\"", (char *) NULL);
    return TCL_ERROR;

bad_suboption:
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
	    " ", argv[1], " on|off\"", (char *) NULL);
    return TCL_ERROR;
}

/*
 *----------------------------------------------------------------------
 *
 * CheckmemCmd --
 *
 *	This is the command procedure for the "checkmem" command, which
 *	causes the application to exit after printing information about
 *	memory usage to the file passed to this command as its first
 *	argument.
 *
 * Results:
 *	Returns a standard Tcl completion code.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
CheckmemCmd(clientData, interp, argc, argv)
    ClientData clientData;		/* Not used. */
    Tcl_Interp *interp;			/* Interpreter for evaluation. */
    int argc;				/* Number of arguments. */
    CONST char *argv[];			/* String values of arguments. */
{
    if (argc != 2) {
	Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
		" fileName\"", (char *) NULL);
	return TCL_ERROR;
    }
    tclMemDumpFileName = dumpFile;
    strcpy(tclMemDumpFileName, argv[1]);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_InitMemory --
 *
 *	Create the "memory" and "checkmem" commands in the given
 *	interpreter.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	New commands are added to the interpreter.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_InitMemory(interp)
    Tcl_Interp *interp;	/* Interpreter in which commands should be added */
{
    TclInitDbCkalloc();
    Tcl_CreateCommand (interp, "memory", MemoryCmd, (ClientData) NULL,
	    (Tcl_CmdDeleteProc *) NULL);
    Tcl_CreateCommand(interp, "checkmem", CheckmemCmd, (ClientData) 0,
	    (Tcl_CmdDeleteProc *) NULL);
}


#else	/* TCL_MEM_DEBUG */

/* This is the !TCL_MEM_DEBUG case */

#undef Tcl_InitMemory
#undef Tcl_DumpActiveMemory
#undef Tcl_ValidateAllMemory


/*
 *----------------------------------------------------------------------
 *
 * Tcl_Alloc --
 *     Interface to TclpAlloc when TCL_MEM_DEBUG is disabled.  It does check
 *     that memory was actually allocated.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_Alloc (size)
    unsigned int size;
{
    char *result;

    result = TclpAlloc(size);
    /*
     * Most systems will not alloc(0), instead bumping it to one so
     * that NULL isn't returned.  Some systems (AIX, Tru64) will alloc(0)
     * by returning NULL, so we have to check that the NULL we get is
     * not in response to alloc(0).
     *
     * The ANSI spec actually says that systems either return NULL *or*
     * a special pointer on failure, but we only check for NULL
     */
    if ((result == NULL) && size) {
	panic("unable to alloc %u bytes", size);
    }
    return result;
}

char *
Tcl_DbCkalloc(size, file, line)
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *result;

    result = (char *) TclpAlloc(size);

    if ((result == NULL) && size) {
        fflush(stdout);
        panic("unable to alloc %u bytes, %s line %d", size, file, line);
    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AttemptAlloc --
 *     Interface to TclpAlloc when TCL_MEM_DEBUG is disabled.  It does not
 *     check that memory was actually allocated.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_AttemptAlloc (size)
    unsigned int size;
{
    char *result;

    result = TclpAlloc(size);
    return result;
}

char *
Tcl_AttemptDbCkalloc(size, file, line)
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *result;

    result = (char *) TclpAlloc(size);
    return result;
}


/*
 *----------------------------------------------------------------------
 *
 * Tcl_Realloc --
 *     Interface to TclpRealloc when TCL_MEM_DEBUG is disabled.  It does
 *     check that memory was actually allocated.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_Realloc(ptr, size)
    char *ptr;
    unsigned int size;
{
    char *result;

    result = TclpRealloc(ptr, size);

    if ((result == NULL) && size) {
	panic("unable to realloc %u bytes", size);
    }
    return result;
}

char *
Tcl_DbCkrealloc(ptr, size, file, line)
    char        *ptr;
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *result;

    result = (char *) TclpRealloc(ptr, size);

    if ((result == NULL) && size) {
        fflush(stdout);
        panic("unable to realloc %u bytes, %s line %d", size, file, line);
    }
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AttemptRealloc --
 *     Interface to TclpRealloc when TCL_MEM_DEBUG is disabled.  It does
 *     not check that memory was actually allocated.
 *
 *----------------------------------------------------------------------
 */

char *
Tcl_AttemptRealloc(ptr, size)
    char *ptr;
    unsigned int size;
{
    char *result;

    result = TclpRealloc(ptr, size);
    return result;
}

char *
Tcl_AttemptDbCkrealloc(ptr, size, file, line)
    char        *ptr;
    unsigned int size;
    CONST char  *file;
    int          line;
{
    char *result;

    result = (char *) TclpRealloc(ptr, size);
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Free --
 *     Interface to TclpFree when TCL_MEM_DEBUG is disabled.  Done here
 *     rather in the macro to keep some modules from being compiled with
 *     TCL_MEM_DEBUG enabled and some with it disabled.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_Free (ptr)
    char *ptr;
{
    TclpFree(ptr);
}

int
Tcl_DbCkfree(ptr, file, line)
    char       *ptr;
    CONST char *file;
    int         line;
{
    TclpFree(ptr);
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_InitMemory --
 *     Dummy initialization for memory command, which is only available
 *     if TCL_MEM_DEBUG is on.
 *
 *----------------------------------------------------------------------
 */
	/* ARGSUSED */
void
Tcl_InitMemory(interp)
    Tcl_Interp *interp;
{
}

int
Tcl_DumpActiveMemory(fileName)
    CONST char *fileName;
{
    return TCL_OK;
}

void
Tcl_ValidateAllMemory(file, line)
    CONST char *file;
    int         line;
{
}

void
TclDumpMemoryInfo(outFile)
    FILE *outFile;
{
}

#endif	/* TCL_MEM_DEBUG */

/*
 *---------------------------------------------------------------------------
 *
 * TclFinalizeMemorySubsystem --
 *
 *	This procedure is called to finalize all the structures that
 *	are used by the memory allocator on a per-process basis.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	This subsystem is self-initializing, since memory can be
 *	allocated before Tcl is formally initialized.  After this call,
 *	this subsystem has been reset to its initial state and is
 *	usable again.
 *
 *---------------------------------------------------------------------------
 */

void
TclFinalizeMemorySubsystem()
{
#ifdef TCL_MEM_DEBUG
    if (tclMemDumpFileName != NULL) {
	Tcl_DumpActiveMemory(tclMemDumpFileName);
    } else if (onExitMemDumpFileName != NULL) {
	Tcl_DumpActiveMemory(onExitMemDumpFileName);
    }
    Tcl_MutexLock(ckallocMutexPtr);
    if (curTagPtr != NULL) {
	TclpFree((char *) curTagPtr);
	curTagPtr = NULL;
    }
    allocHead = NULL;
    Tcl_MutexUnlock(ckallocMutexPtr);
#endif

#if USE_TCLALLOC
    TclFinalizeAllocSubsystem();
#endif
}