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+/*
+** 2007 August 15
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains low-level memory allocation drivers for when
+** SQLite will use the standard C-library malloc/realloc/free interface
+** to obtain the memory it needs while adding lots of additional debugging
+** information to each allocation in order to help detect and fix memory
+** leaks and memory usage errors.
+**
+** This file contains implementations of the low-level memory allocation
+** routines specified in the sqlite3_mem_methods object.
+*/
+#include "sqliteInt.h"
+
+/*
+** This version of the memory allocator is used only if the
+** SQLITE_MEMDEBUG macro is defined
+*/
+#ifdef SQLITE_MEMDEBUG
+
+/*
+** The backtrace functionality is only available with GLIBC
+*/
+#ifdef __GLIBC__
+ extern int backtrace(void**,int);
+ extern void backtrace_symbols_fd(void*const*,int,int);
+#else
+# define backtrace(A,B) 1
+# define backtrace_symbols_fd(A,B,C)
+#endif
+#include <stdio.h>
+
+/*
+** Each memory allocation looks like this:
+**
+** ------------------------------------------------------------------------
+** | Title | backtrace pointers | MemBlockHdr | allocation | EndGuard |
+** ------------------------------------------------------------------------
+**
+** The application code sees only a pointer to the allocation. We have
+** to back up from the allocation pointer to find the MemBlockHdr. The
+** MemBlockHdr tells us the size of the allocation and the number of
+** backtrace pointers. There is also a guard word at the end of the
+** MemBlockHdr.
+*/
+struct MemBlockHdr {
+ i64 iSize; /* Size of this allocation */
+ struct MemBlockHdr *pNext, *pPrev; /* Linked list of all unfreed memory */
+ char nBacktrace; /* Number of backtraces on this alloc */
+ char nBacktraceSlots; /* Available backtrace slots */
+ u8 nTitle; /* Bytes of title; includes '\0' */
+ u8 eType; /* Allocation type code */
+ int iForeGuard; /* Guard word for sanity */
+};
+
+/*
+** Guard words
+*/
+#define FOREGUARD 0x80F5E153
+#define REARGUARD 0xE4676B53
+
+/*
+** Number of malloc size increments to track.
+*/
+#define NCSIZE 1000
+
+/*
+** All of the static variables used by this module are collected
+** into a single structure named "mem". This is to keep the
+** static variables organized and to reduce namespace pollution
+** when this module is combined with other in the amalgamation.
+*/
+static struct {
+
+ /*
+ ** Mutex to control access to the memory allocation subsystem.
+ */
+ sqlite3_mutex *mutex;
+
+ /*
+ ** Head and tail of a linked list of all outstanding allocations
+ */
+ struct MemBlockHdr *pFirst;
+ struct MemBlockHdr *pLast;
+
+ /*
+ ** The number of levels of backtrace to save in new allocations.
+ */
+ int nBacktrace;
+ void (*xBacktrace)(int, int, void **);
+
+ /*
+ ** Title text to insert in front of each block
+ */
+ int nTitle; /* Bytes of zTitle to save. Includes '\0' and padding */
+ char zTitle[100]; /* The title text */
+
+ /*
+ ** sqlite3MallocDisallow() increments the following counter.
+ ** sqlite3MallocAllow() decrements it.
+ */
+ int disallow; /* Do not allow memory allocation */
+
+ /*
+ ** Gather statistics on the sizes of memory allocations.
+ ** nAlloc[i] is the number of allocation attempts of i*8
+ ** bytes. i==NCSIZE is the number of allocation attempts for
+ ** sizes more than NCSIZE*8 bytes.
+ */
+ int nAlloc[NCSIZE]; /* Total number of allocations */
+ int nCurrent[NCSIZE]; /* Current number of allocations */
+ int mxCurrent[NCSIZE]; /* Highwater mark for nCurrent */
+
+} mem;
+
+
+/*
+** Adjust memory usage statistics
+*/
+static void adjustStats(int iSize, int increment){
+ int i = ROUND8(iSize)/8;
+ if( i>NCSIZE-1 ){
+ i = NCSIZE - 1;
+ }
+ if( increment>0 ){
+ mem.nAlloc[i]++;
+ mem.nCurrent[i]++;
+ if( mem.nCurrent[i]>mem.mxCurrent[i] ){
+ mem.mxCurrent[i] = mem.nCurrent[i];
+ }
+ }else{
+ mem.nCurrent[i]--;
+ assert( mem.nCurrent[i]>=0 );
+ }
+}
+
+/*
+** Given an allocation, find the MemBlockHdr for that allocation.
+**
+** This routine checks the guards at either end of the allocation and
+** if they are incorrect it asserts.
+*/
+static struct MemBlockHdr *sqlite3MemsysGetHeader(const void *pAllocation){
+ struct MemBlockHdr *p;
+ int *pInt;
+ u8 *pU8;
+ int nReserve;
+
+ p = (struct MemBlockHdr*)pAllocation;
+ p--;
+ assert( p->iForeGuard==(int)FOREGUARD );
+ nReserve = ROUND8(p->iSize);
+ pInt = (int*)pAllocation;
+ pU8 = (u8*)pAllocation;
+ assert( pInt[nReserve/sizeof(int)]==(int)REARGUARD );
+ /* This checks any of the "extra" bytes allocated due
+ ** to rounding up to an 8 byte boundary to ensure
+ ** they haven't been overwritten.
+ */
+ while( nReserve-- > p->iSize ) assert( pU8[nReserve]==0x65 );
+ return p;
+}
+
+/*
+** Return the number of bytes currently allocated at address p.
+*/
+static int sqlite3MemSize(void *p){
+ struct MemBlockHdr *pHdr;
+ if( !p ){
+ return 0;
+ }
+ pHdr = sqlite3MemsysGetHeader(p);
+ return (int)pHdr->iSize;
+}
+
+/*
+** Initialize the memory allocation subsystem.
+*/
+static int sqlite3MemInit(void *NotUsed){
+ UNUSED_PARAMETER(NotUsed);
+ assert( (sizeof(struct MemBlockHdr)&7) == 0 );
+ if( !sqlite3GlobalConfig.bMemstat ){
+ /* If memory status is enabled, then the malloc.c wrapper will already
+ ** hold the STATIC_MEM mutex when the routines here are invoked. */
+ mem.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
+ }
+ return SQLITE_OK;
+}
+
+/*
+** Deinitialize the memory allocation subsystem.
+*/
+static void sqlite3MemShutdown(void *NotUsed){
+ UNUSED_PARAMETER(NotUsed);
+ mem.mutex = 0;
+}
+
+/*
+** Round up a request size to the next valid allocation size.
+*/
+static int sqlite3MemRoundup(int n){
+ return ROUND8(n);
+}
+
+/*
+** Fill a buffer with pseudo-random bytes. This is used to preset
+** the content of a new memory allocation to unpredictable values and
+** to clear the content of a freed allocation to unpredictable values.
+*/
+static void randomFill(char *pBuf, int nByte){
+ unsigned int x, y, r;
+ x = SQLITE_PTR_TO_INT(pBuf);
+ y = nByte | 1;
+ while( nByte >= 4 ){
+ x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+ y = y*1103515245 + 12345;
+ r = x ^ y;
+ *(int*)pBuf = r;
+ pBuf += 4;
+ nByte -= 4;
+ }
+ while( nByte-- > 0 ){
+ x = (x>>1) ^ (-(int)(x&1) & 0xd0000001);
+ y = y*1103515245 + 12345;
+ r = x ^ y;
+ *(pBuf++) = r & 0xff;
+ }
+}
+
+/*
+** Allocate nByte bytes of memory.
+*/
+static void *sqlite3MemMalloc(int nByte){
+ struct MemBlockHdr *pHdr;
+ void **pBt;
+ char *z;
+ int *pInt;
+ void *p = 0;
+ int totalSize;
+ int nReserve;
+ sqlite3_mutex_enter(mem.mutex);
+ assert( mem.disallow==0 );
+ nReserve = ROUND8(nByte);
+ totalSize = nReserve + sizeof(*pHdr) + sizeof(int) +
+ mem.nBacktrace*sizeof(void*) + mem.nTitle;
+ p = malloc(totalSize);
+ if( p ){
+ z = p;
+ pBt = (void**)&z[mem.nTitle];
+ pHdr = (struct MemBlockHdr*)&pBt[mem.nBacktrace];
+ pHdr->pNext = 0;
+ pHdr->pPrev = mem.pLast;
+ if( mem.pLast ){
+ mem.pLast->pNext = pHdr;
+ }else{
+ mem.pFirst = pHdr;
+ }
+ mem.pLast = pHdr;
+ pHdr->iForeGuard = FOREGUARD;
+ pHdr->eType = MEMTYPE_HEAP;
+ pHdr->nBacktraceSlots = mem.nBacktrace;
+ pHdr->nTitle = mem.nTitle;
+ if( mem.nBacktrace ){
+ void *aAddr[40];
+ pHdr->nBacktrace = backtrace(aAddr, mem.nBacktrace+1)-1;
+ memcpy(pBt, &aAddr[1], pHdr->nBacktrace*sizeof(void*));
+ assert(pBt[0]);
+ if( mem.xBacktrace ){
+ mem.xBacktrace(nByte, pHdr->nBacktrace-1, &aAddr[1]);
+ }
+ }else{
+ pHdr->nBacktrace = 0;
+ }
+ if( mem.nTitle ){
+ memcpy(z, mem.zTitle, mem.nTitle);
+ }
+ pHdr->iSize = nByte;
+ adjustStats(nByte, +1);
+ pInt = (int*)&pHdr[1];
+ pInt[nReserve/sizeof(int)] = REARGUARD;
+ randomFill((char*)pInt, nByte);
+ memset(((char*)pInt)+nByte, 0x65, nReserve-nByte);
+ p = (void*)pInt;
+ }
+ sqlite3_mutex_leave(mem.mutex);
+ return p;
+}
+
+/*
+** Free memory.
+*/
+static void sqlite3MemFree(void *pPrior){
+ struct MemBlockHdr *pHdr;
+ void **pBt;
+ char *z;
+ assert( sqlite3GlobalConfig.bMemstat || sqlite3GlobalConfig.bCoreMutex==0
+ || mem.mutex!=0 );
+ pHdr = sqlite3MemsysGetHeader(pPrior);
+ pBt = (void**)pHdr;
+ pBt -= pHdr->nBacktraceSlots;
+ sqlite3_mutex_enter(mem.mutex);
+ if( pHdr->pPrev ){
+ assert( pHdr->pPrev->pNext==pHdr );
+ pHdr->pPrev->pNext = pHdr->pNext;
+ }else{
+ assert( mem.pFirst==pHdr );
+ mem.pFirst = pHdr->pNext;
+ }
+ if( pHdr->pNext ){
+ assert( pHdr->pNext->pPrev==pHdr );
+ pHdr->pNext->pPrev = pHdr->pPrev;
+ }else{
+ assert( mem.pLast==pHdr );
+ mem.pLast = pHdr->pPrev;
+ }
+ z = (char*)pBt;
+ z -= pHdr->nTitle;
+ adjustStats((int)pHdr->iSize, -1);
+ randomFill(z, sizeof(void*)*pHdr->nBacktraceSlots + sizeof(*pHdr) +
+ (int)pHdr->iSize + sizeof(int) + pHdr->nTitle);
+ free(z);
+ sqlite3_mutex_leave(mem.mutex);
+}
+
+/*
+** Change the size of an existing memory allocation.
+**
+** For this debugging implementation, we *always* make a copy of the
+** allocation into a new place in memory. In this way, if the
+** higher level code is using pointer to the old allocation, it is
+** much more likely to break and we are much more liking to find
+** the error.
+*/
+static void *sqlite3MemRealloc(void *pPrior, int nByte){
+ struct MemBlockHdr *pOldHdr;
+ void *pNew;
+ assert( mem.disallow==0 );
+ assert( (nByte & 7)==0 ); /* EV: R-46199-30249 */
+ pOldHdr = sqlite3MemsysGetHeader(pPrior);
+ pNew = sqlite3MemMalloc(nByte);
+ if( pNew ){
+ memcpy(pNew, pPrior, (int)(nByte<pOldHdr->iSize ? nByte : pOldHdr->iSize));
+ if( nByte>pOldHdr->iSize ){
+ randomFill(&((char*)pNew)[pOldHdr->iSize], nByte - (int)pOldHdr->iSize);
+ }
+ sqlite3MemFree(pPrior);
+ }
+ return pNew;
+}
+
+/*
+** Populate the low-level memory allocation function pointers in
+** sqlite3GlobalConfig.m with pointers to the routines in this file.
+*/
+void sqlite3MemSetDefault(void){
+ static const sqlite3_mem_methods defaultMethods = {
+ sqlite3MemMalloc,
+ sqlite3MemFree,
+ sqlite3MemRealloc,
+ sqlite3MemSize,
+ sqlite3MemRoundup,
+ sqlite3MemInit,
+ sqlite3MemShutdown,
+ 0
+ };
+ sqlite3_config(SQLITE_CONFIG_MALLOC, &defaultMethods);
+}
+
+/*
+** Set the "type" of an allocation.
+*/
+void sqlite3MemdebugSetType(void *p, u8 eType){
+ if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+ struct MemBlockHdr *pHdr;
+ pHdr = sqlite3MemsysGetHeader(p);
+ assert( pHdr->iForeGuard==FOREGUARD );
+ pHdr->eType = eType;
+ }
+}
+
+/*
+** Return TRUE if the mask of type in eType matches the type of the
+** allocation p. Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation. For example:
+**
+** assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
+*/
+int sqlite3MemdebugHasType(const void *p, u8 eType){
+ int rc = 1;
+ if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+ struct MemBlockHdr *pHdr;
+ pHdr = sqlite3MemsysGetHeader(p);
+ assert( pHdr->iForeGuard==FOREGUARD ); /* Allocation is valid */
+ if( (pHdr->eType&eType)==0 ){
+ rc = 0;
+ }
+ }
+ return rc;
+}
+
+/*
+** Return TRUE if the mask of type in eType matches no bits of the type of the
+** allocation p. Also return true if p==NULL.
+**
+** This routine is designed for use within an assert() statement, to
+** verify the type of an allocation. For example:
+**
+** assert( sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
+*/
+int sqlite3MemdebugNoType(const void *p, u8 eType){
+ int rc = 1;
+ if( p && sqlite3GlobalConfig.m.xFree==sqlite3MemFree ){
+ struct MemBlockHdr *pHdr;
+ pHdr = sqlite3MemsysGetHeader(p);
+ assert( pHdr->iForeGuard==FOREGUARD ); /* Allocation is valid */
+ if( (pHdr->eType&eType)!=0 ){
+ rc = 0;
+ }
+ }
+ return rc;
+}
+
+/*
+** Set the number of backtrace levels kept for each allocation.
+** A value of zero turns off backtracing. The number is always rounded
+** up to a multiple of 2.
+*/
+void sqlite3MemdebugBacktrace(int depth){
+ if( depth<0 ){ depth = 0; }
+ if( depth>20 ){ depth = 20; }
+ depth = (depth+1)&0xfe;
+ mem.nBacktrace = depth;
+}
+
+void sqlite3MemdebugBacktraceCallback(void (*xBacktrace)(int, int, void **)){
+ mem.xBacktrace = xBacktrace;
+}
+
+/*
+** Set the title string for subsequent allocations.
+*/
+void sqlite3MemdebugSettitle(const char *zTitle){
+ unsigned int n = sqlite3Strlen30(zTitle) + 1;
+ sqlite3_mutex_enter(mem.mutex);
+ if( n>=sizeof(mem.zTitle) ) n = sizeof(mem.zTitle)-1;
+ memcpy(mem.zTitle, zTitle, n);
+ mem.zTitle[n] = 0;
+ mem.nTitle = ROUND8(n);
+ sqlite3_mutex_leave(mem.mutex);
+}
+
+void sqlite3MemdebugSync(){
+ struct MemBlockHdr *pHdr;
+ for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+ void **pBt = (void**)pHdr;
+ pBt -= pHdr->nBacktraceSlots;
+ mem.xBacktrace((int)pHdr->iSize, pHdr->nBacktrace-1, &pBt[1]);
+ }
+}
+
+/*
+** Open the file indicated and write a log of all unfreed memory
+** allocations into that log.
+*/
+void sqlite3MemdebugDump(const char *zFilename){
+ FILE *out;
+ struct MemBlockHdr *pHdr;
+ void **pBt;
+ int i;
+ out = fopen(zFilename, "w");
+ if( out==0 ){
+ fprintf(stderr, "** Unable to output memory debug output log: %s **\n",
+ zFilename);
+ return;
+ }
+ for(pHdr=mem.pFirst; pHdr; pHdr=pHdr->pNext){
+ char *z = (char*)pHdr;
+ z -= pHdr->nBacktraceSlots*sizeof(void*) + pHdr->nTitle;
+ fprintf(out, "**** %lld bytes at %p from %s ****\n",
+ pHdr->iSize, &pHdr[1], pHdr->nTitle ? z : "???");
+ if( pHdr->nBacktrace ){
+ fflush(out);
+ pBt = (void**)pHdr;
+ pBt -= pHdr->nBacktraceSlots;
+ backtrace_symbols_fd(pBt, pHdr->nBacktrace, fileno(out));
+ fprintf(out, "\n");
+ }
+ }
+ fprintf(out, "COUNTS:\n");
+ for(i=0; i<NCSIZE-1; i++){
+ if( mem.nAlloc[i] ){
+ fprintf(out, " %5d: %10d %10d %10d\n",
+ i*8, mem.nAlloc[i], mem.nCurrent[i], mem.mxCurrent[i]);
+ }
+ }
+ if( mem.nAlloc[NCSIZE-1] ){
+ fprintf(out, " %5d: %10d %10d %10d\n",
+ NCSIZE*8-8, mem.nAlloc[NCSIZE-1],
+ mem.nCurrent[NCSIZE-1], mem.mxCurrent[NCSIZE-1]);
+ }
+ fclose(out);
+}
+
+/*
+** Return the number of times sqlite3MemMalloc() has been called.
+*/
+int sqlite3MemdebugMallocCount(){
+ int i;
+ int nTotal = 0;
+ for(i=0; i<NCSIZE; i++){
+ nTotal += mem.nAlloc[i];
+ }
+ return nTotal;
+}
+
+
+#endif /* SQLITE_MEMDEBUG */
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