000001 /*
000002 ** 2001 September 15
000003 **
000004 ** The author disclaims copyright to this source code. In place of
000005 ** a legal notice, here is a blessing:
000006 **
000007 ** May you do good and not evil.
000008 ** May you find forgiveness for yourself and forgive others.
000009 ** May you share freely, never taking more than you give.
000010 **
000011 *************************************************************************
000012 **
000013 ** Memory allocation functions used throughout sqlite.
000014 */
000015 #include "sqliteInt.h"
000016 #include <stdarg.h>
000017
000018 /*
000019 ** Attempt to release up to n bytes of non-essential memory currently
000020 ** held by SQLite. An example of non-essential memory is memory used to
000021 ** cache database pages that are not currently in use.
000022 */
000023 int sqlite3_release_memory(int n){
000024 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
000025 return sqlite3PcacheReleaseMemory(n);
000026 #else
000027 /* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine
000028 ** is a no-op returning zero if SQLite is not compiled with
000029 ** SQLITE_ENABLE_MEMORY_MANAGEMENT. */
000030 UNUSED_PARAMETER(n);
000031 return 0;
000032 #endif
000033 }
000034
000035 /*
000036 ** Default value of the hard heap limit. 0 means "no limit".
000037 */
000038 #ifndef SQLITE_MAX_MEMORY
000039 # define SQLITE_MAX_MEMORY 0
000040 #endif
000041
000042 /*
000043 ** State information local to the memory allocation subsystem.
000044 */
000045 static SQLITE_WSD struct Mem0Global {
000046 sqlite3_mutex *mutex; /* Mutex to serialize access */
000047 sqlite3_int64 alarmThreshold; /* The soft heap limit */
000048 sqlite3_int64 hardLimit; /* The hard upper bound on memory */
000049
000050 /*
000051 ** True if heap is nearly "full" where "full" is defined by the
000052 ** sqlite3_soft_heap_limit() setting.
000053 */
000054 int nearlyFull;
000055 } mem0 = { 0, SQLITE_MAX_MEMORY, SQLITE_MAX_MEMORY, 0 };
000056
000057 #define mem0 GLOBAL(struct Mem0Global, mem0)
000058
000059 /*
000060 ** Return the memory allocator mutex. sqlite3_status() needs it.
000061 */
000062 sqlite3_mutex *sqlite3MallocMutex(void){
000063 return mem0.mutex;
000064 }
000065
000066 #ifndef SQLITE_OMIT_DEPRECATED
000067 /*
000068 ** Deprecated external interface. It used to set an alarm callback
000069 ** that was invoked when memory usage grew too large. Now it is a
000070 ** no-op.
000071 */
000072 int sqlite3_memory_alarm(
000073 void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
000074 void *pArg,
000075 sqlite3_int64 iThreshold
000076 ){
000077 (void)xCallback;
000078 (void)pArg;
000079 (void)iThreshold;
000080 return SQLITE_OK;
000081 }
000082 #endif
000083
000084 /*
000085 ** Set the soft heap-size limit for the library. An argument of
000086 ** zero disables the limit. A negative argument is a no-op used to
000087 ** obtain the return value.
000088 **
000089 ** The return value is the value of the heap limit just before this
000090 ** interface was called.
000091 **
000092 ** If the hard heap limit is enabled, then the soft heap limit cannot
000093 ** be disabled nor raised above the hard heap limit.
000094 */
000095 sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
000096 sqlite3_int64 priorLimit;
000097 sqlite3_int64 excess;
000098 sqlite3_int64 nUsed;
000099 #ifndef SQLITE_OMIT_AUTOINIT
000100 int rc = sqlite3_initialize();
000101 if( rc ) return -1;
000102 #endif
000103 sqlite3_mutex_enter(mem0.mutex);
000104 priorLimit = mem0.alarmThreshold;
000105 if( n<0 ){
000106 sqlite3_mutex_leave(mem0.mutex);
000107 return priorLimit;
000108 }
000109 if( mem0.hardLimit>0 && (n>mem0.hardLimit || n==0) ){
000110 n = mem0.hardLimit;
000111 }
000112 mem0.alarmThreshold = n;
000113 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
000114 AtomicStore(&mem0.nearlyFull, n>0 && n<=nUsed);
000115 sqlite3_mutex_leave(mem0.mutex);
000116 excess = sqlite3_memory_used() - n;
000117 if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));
000118 return priorLimit;
000119 }
000120 void sqlite3_soft_heap_limit(int n){
000121 if( n<0 ) n = 0;
000122 sqlite3_soft_heap_limit64(n);
000123 }
000124
000125 /*
000126 ** Set the hard heap-size limit for the library. An argument of zero
000127 ** disables the hard heap limit. A negative argument is a no-op used
000128 ** to obtain the return value without affecting the hard heap limit.
000129 **
000130 ** The return value is the value of the hard heap limit just prior to
000131 ** calling this interface.
000132 **
000133 ** Setting the hard heap limit will also activate the soft heap limit
000134 ** and constrain the soft heap limit to be no more than the hard heap
000135 ** limit.
000136 */
000137 sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 n){
000138 sqlite3_int64 priorLimit;
000139 #ifndef SQLITE_OMIT_AUTOINIT
000140 int rc = sqlite3_initialize();
000141 if( rc ) return -1;
000142 #endif
000143 sqlite3_mutex_enter(mem0.mutex);
000144 priorLimit = mem0.hardLimit;
000145 if( n>=0 ){
000146 mem0.hardLimit = n;
000147 if( n<mem0.alarmThreshold || mem0.alarmThreshold==0 ){
000148 mem0.alarmThreshold = n;
000149 }
000150 }
000151 sqlite3_mutex_leave(mem0.mutex);
000152 return priorLimit;
000153 }
000154
000155
000156 /*
000157 ** Initialize the memory allocation subsystem.
000158 */
000159 int sqlite3MallocInit(void){
000160 int rc;
000161 if( sqlite3GlobalConfig.m.xMalloc==0 ){
000162 sqlite3MemSetDefault();
000163 }
000164 mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);
000165 if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512
000166 || sqlite3GlobalConfig.nPage<=0 ){
000167 sqlite3GlobalConfig.pPage = 0;
000168 sqlite3GlobalConfig.szPage = 0;
000169 }
000170 rc = sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);
000171 if( rc!=SQLITE_OK ) memset(&mem0, 0, sizeof(mem0));
000172 return rc;
000173 }
000174
000175 /*
000176 ** Return true if the heap is currently under memory pressure - in other
000177 ** words if the amount of heap used is close to the limit set by
000178 ** sqlite3_soft_heap_limit().
000179 */
000180 int sqlite3HeapNearlyFull(void){
000181 return AtomicLoad(&mem0.nearlyFull);
000182 }
000183
000184 /*
000185 ** Deinitialize the memory allocation subsystem.
000186 */
000187 void sqlite3MallocEnd(void){
000188 if( sqlite3GlobalConfig.m.xShutdown ){
000189 sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);
000190 }
000191 memset(&mem0, 0, sizeof(mem0));
000192 }
000193
000194 /*
000195 ** Return the amount of memory currently checked out.
000196 */
000197 sqlite3_int64 sqlite3_memory_used(void){
000198 sqlite3_int64 res, mx;
000199 sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, 0);
000200 return res;
000201 }
000202
000203 /*
000204 ** Return the maximum amount of memory that has ever been
000205 ** checked out since either the beginning of this process
000206 ** or since the most recent reset.
000207 */
000208 sqlite3_int64 sqlite3_memory_highwater(int resetFlag){
000209 sqlite3_int64 res, mx;
000210 sqlite3_status64(SQLITE_STATUS_MEMORY_USED, &res, &mx, resetFlag);
000211 return mx;
000212 }
000213
000214 /*
000215 ** Trigger the alarm
000216 */
000217 static void sqlite3MallocAlarm(int nByte){
000218 if( mem0.alarmThreshold<=0 ) return;
000219 sqlite3_mutex_leave(mem0.mutex);
000220 sqlite3_release_memory(nByte);
000221 sqlite3_mutex_enter(mem0.mutex);
000222 }
000223
000224 /*
000225 ** Do a memory allocation with statistics and alarms. Assume the
000226 ** lock is already held.
000227 */
000228 static void mallocWithAlarm(int n, void **pp){
000229 void *p;
000230 int nFull;
000231 assert( sqlite3_mutex_held(mem0.mutex) );
000232 assert( n>0 );
000233
000234 /* In Firefox (circa 2017-02-08), xRoundup() is remapped to an internal
000235 ** implementation of malloc_good_size(), which must be called in debug
000236 ** mode and specifically when the DMD "Dark Matter Detector" is enabled
000237 ** or else a crash results. Hence, do not attempt to optimize out the
000238 ** following xRoundup() call. */
000239 nFull = sqlite3GlobalConfig.m.xRoundup(n);
000240
000241 sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, n);
000242 if( mem0.alarmThreshold>0 ){
000243 sqlite3_int64 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
000244 if( nUsed >= mem0.alarmThreshold - nFull ){
000245 AtomicStore(&mem0.nearlyFull, 1);
000246 sqlite3MallocAlarm(nFull);
000247 if( mem0.hardLimit ){
000248 nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
000249 if( nUsed >= mem0.hardLimit - nFull ){
000250 *pp = 0;
000251 return;
000252 }
000253 }
000254 }else{
000255 AtomicStore(&mem0.nearlyFull, 0);
000256 }
000257 }
000258 p = sqlite3GlobalConfig.m.xMalloc(nFull);
000259 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
000260 if( p==0 && mem0.alarmThreshold>0 ){
000261 sqlite3MallocAlarm(nFull);
000262 p = sqlite3GlobalConfig.m.xMalloc(nFull);
000263 }
000264 #endif
000265 if( p ){
000266 nFull = sqlite3MallocSize(p);
000267 sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nFull);
000268 sqlite3StatusUp(SQLITE_STATUS_MALLOC_COUNT, 1);
000269 }
000270 *pp = p;
000271 }
000272
000273 /*
000274 ** Maximum size of any single memory allocation.
000275 **
000276 ** This is not a limit on the total amount of memory used. This is
000277 ** a limit on the size parameter to sqlite3_malloc() and sqlite3_realloc().
000278 **
000279 ** The upper bound is slightly less than 2GiB: 0x7ffffeff == 2,147,483,391
000280 ** This provides a 256-byte safety margin for defense against 32-bit
000281 ** signed integer overflow bugs when computing memory allocation sizes.
000282 ** Paranoid applications might want to reduce the maximum allocation size
000283 ** further for an even larger safety margin. 0x3fffffff or 0x0fffffff
000284 ** or even smaller would be reasonable upper bounds on the size of a memory
000285 ** allocations for most applications.
000286 */
000287 #ifndef SQLITE_MAX_ALLOCATION_SIZE
000288 # define SQLITE_MAX_ALLOCATION_SIZE 2147483391
000289 #endif
000290 #if SQLITE_MAX_ALLOCATION_SIZE>2147483391
000291 # error Maximum size for SQLITE_MAX_ALLOCATION_SIZE is 2147483391
000292 #endif
000293
000294 /*
000295 ** Allocate memory. This routine is like sqlite3_malloc() except that it
000296 ** assumes the memory subsystem has already been initialized.
000297 */
000298 void *sqlite3Malloc(u64 n){
000299 void *p;
000300 if( n==0 || n>SQLITE_MAX_ALLOCATION_SIZE ){
000301 p = 0;
000302 }else if( sqlite3GlobalConfig.bMemstat ){
000303 sqlite3_mutex_enter(mem0.mutex);
000304 mallocWithAlarm((int)n, &p);
000305 sqlite3_mutex_leave(mem0.mutex);
000306 }else{
000307 p = sqlite3GlobalConfig.m.xMalloc((int)n);
000308 }
000309 assert( EIGHT_BYTE_ALIGNMENT(p) ); /* IMP: R-11148-40995 */
000310 return p;
000311 }
000312
000313 /*
000314 ** This version of the memory allocation is for use by the application.
000315 ** First make sure the memory subsystem is initialized, then do the
000316 ** allocation.
000317 */
000318 void *sqlite3_malloc(int n){
000319 #ifndef SQLITE_OMIT_AUTOINIT
000320 if( sqlite3_initialize() ) return 0;
000321 #endif
000322 return n<=0 ? 0 : sqlite3Malloc(n);
000323 }
000324 void *sqlite3_malloc64(sqlite3_uint64 n){
000325 #ifndef SQLITE_OMIT_AUTOINIT
000326 if( sqlite3_initialize() ) return 0;
000327 #endif
000328 return sqlite3Malloc(n);
000329 }
000330
000331 /*
000332 ** TRUE if p is a lookaside memory allocation from db
000333 */
000334 #ifndef SQLITE_OMIT_LOOKASIDE
000335 static int isLookaside(sqlite3 *db, const void *p){
000336 return SQLITE_WITHIN(p, db->lookaside.pStart, db->lookaside.pTrueEnd);
000337 }
000338 #else
000339 #define isLookaside(A,B) 0
000340 #endif
000341
000342 /*
000343 ** Return the size of a memory allocation previously obtained from
000344 ** sqlite3Malloc() or sqlite3_malloc().
000345 */
000346 int sqlite3MallocSize(const void *p){
000347 assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
000348 return sqlite3GlobalConfig.m.xSize((void*)p);
000349 }
000350 static int lookasideMallocSize(sqlite3 *db, const void *p){
000351 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000352 return p<db->lookaside.pMiddle ? db->lookaside.szTrue : LOOKASIDE_SMALL;
000353 #else
000354 return db->lookaside.szTrue;
000355 #endif
000356 }
000357 int sqlite3DbMallocSize(sqlite3 *db, const void *p){
000358 assert( p!=0 );
000359 #ifdef SQLITE_DEBUG
000360 if( db==0 ){
000361 assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
000362 assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
000363 }else if( !isLookaside(db,p) ){
000364 assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000365 assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000366 }
000367 #endif
000368 if( db ){
000369 if( ((uptr)p)<(uptr)(db->lookaside.pTrueEnd) ){
000370 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000371 if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
000372 assert( sqlite3_mutex_held(db->mutex) );
000373 return LOOKASIDE_SMALL;
000374 }
000375 #endif
000376 if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
000377 assert( sqlite3_mutex_held(db->mutex) );
000378 return db->lookaside.szTrue;
000379 }
000380 }
000381 }
000382 return sqlite3GlobalConfig.m.xSize((void*)p);
000383 }
000384 sqlite3_uint64 sqlite3_msize(void *p){
000385 assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
000386 assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
000387 return p ? sqlite3GlobalConfig.m.xSize(p) : 0;
000388 }
000389
000390 /*
000391 ** Free memory previously obtained from sqlite3Malloc().
000392 */
000393 void sqlite3_free(void *p){
000394 if( p==0 ) return; /* IMP: R-49053-54554 */
000395 assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );
000396 assert( sqlite3MemdebugNoType(p, (u8)~MEMTYPE_HEAP) );
000397 if( sqlite3GlobalConfig.bMemstat ){
000398 sqlite3_mutex_enter(mem0.mutex);
000399 sqlite3StatusDown(SQLITE_STATUS_MEMORY_USED, sqlite3MallocSize(p));
000400 sqlite3StatusDown(SQLITE_STATUS_MALLOC_COUNT, 1);
000401 sqlite3GlobalConfig.m.xFree(p);
000402 sqlite3_mutex_leave(mem0.mutex);
000403 }else{
000404 sqlite3GlobalConfig.m.xFree(p);
000405 }
000406 }
000407
000408 /*
000409 ** Add the size of memory allocation "p" to the count in
000410 ** *db->pnBytesFreed.
000411 */
000412 static SQLITE_NOINLINE void measureAllocationSize(sqlite3 *db, void *p){
000413 *db->pnBytesFreed += sqlite3DbMallocSize(db,p);
000414 }
000415
000416 /*
000417 ** Free memory that might be associated with a particular database
000418 ** connection. Calling sqlite3DbFree(D,X) for X==0 is a harmless no-op.
000419 ** The sqlite3DbFreeNN(D,X) version requires that X be non-NULL.
000420 */
000421 void sqlite3DbFreeNN(sqlite3 *db, void *p){
000422 assert( db==0 || sqlite3_mutex_held(db->mutex) );
000423 assert( p!=0 );
000424 if( db ){
000425 if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
000426 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000427 if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
000428 LookasideSlot *pBuf = (LookasideSlot*)p;
000429 assert( db->pnBytesFreed==0 );
000430 #ifdef SQLITE_DEBUG
000431 memset(p, 0xaa, LOOKASIDE_SMALL); /* Trash freed content */
000432 #endif
000433 pBuf->pNext = db->lookaside.pSmallFree;
000434 db->lookaside.pSmallFree = pBuf;
000435 return;
000436 }
000437 #endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
000438 if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
000439 LookasideSlot *pBuf = (LookasideSlot*)p;
000440 assert( db->pnBytesFreed==0 );
000441 #ifdef SQLITE_DEBUG
000442 memset(p, 0xaa, db->lookaside.szTrue); /* Trash freed content */
000443 #endif
000444 pBuf->pNext = db->lookaside.pFree;
000445 db->lookaside.pFree = pBuf;
000446 return;
000447 }
000448 }
000449 if( db->pnBytesFreed ){
000450 measureAllocationSize(db, p);
000451 return;
000452 }
000453 }
000454 assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000455 assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000456 assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );
000457 sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
000458 sqlite3_free(p);
000459 }
000460 void sqlite3DbNNFreeNN(sqlite3 *db, void *p){
000461 assert( db!=0 );
000462 assert( sqlite3_mutex_held(db->mutex) );
000463 assert( p!=0 );
000464 if( ((uptr)p)<(uptr)(db->lookaside.pEnd) ){
000465 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000466 if( ((uptr)p)>=(uptr)(db->lookaside.pMiddle) ){
000467 LookasideSlot *pBuf = (LookasideSlot*)p;
000468 assert( db->pnBytesFreed==0 );
000469 #ifdef SQLITE_DEBUG
000470 memset(p, 0xaa, LOOKASIDE_SMALL); /* Trash freed content */
000471 #endif
000472 pBuf->pNext = db->lookaside.pSmallFree;
000473 db->lookaside.pSmallFree = pBuf;
000474 return;
000475 }
000476 #endif /* SQLITE_OMIT_TWOSIZE_LOOKASIDE */
000477 if( ((uptr)p)>=(uptr)(db->lookaside.pStart) ){
000478 LookasideSlot *pBuf = (LookasideSlot*)p;
000479 assert( db->pnBytesFreed==0 );
000480 #ifdef SQLITE_DEBUG
000481 memset(p, 0xaa, db->lookaside.szTrue); /* Trash freed content */
000482 #endif
000483 pBuf->pNext = db->lookaside.pFree;
000484 db->lookaside.pFree = pBuf;
000485 return;
000486 }
000487 }
000488 if( db->pnBytesFreed ){
000489 measureAllocationSize(db, p);
000490 return;
000491 }
000492 assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000493 assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000494 sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
000495 sqlite3_free(p);
000496 }
000497 void sqlite3DbFree(sqlite3 *db, void *p){
000498 assert( db==0 || sqlite3_mutex_held(db->mutex) );
000499 if( p ) sqlite3DbFreeNN(db, p);
000500 }
000501
000502 /*
000503 ** Change the size of an existing memory allocation
000504 */
000505 void *sqlite3Realloc(void *pOld, u64 nBytes){
000506 int nOld, nNew, nDiff;
000507 void *pNew;
000508 assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );
000509 assert( sqlite3MemdebugNoType(pOld, (u8)~MEMTYPE_HEAP) );
000510 if( pOld==0 ){
000511 return sqlite3Malloc(nBytes); /* IMP: R-04300-56712 */
000512 }
000513 if( nBytes==0 ){
000514 sqlite3_free(pOld); /* IMP: R-26507-47431 */
000515 return 0;
000516 }
000517 if( nBytes>=0x7fffff00 ){
000518 /* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */
000519 return 0;
000520 }
000521 nOld = sqlite3MallocSize(pOld);
000522 /* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second
000523 ** argument to xRealloc is always a value returned by a prior call to
000524 ** xRoundup. */
000525 nNew = sqlite3GlobalConfig.m.xRoundup((int)nBytes);
000526 if( nOld==nNew ){
000527 pNew = pOld;
000528 }else if( sqlite3GlobalConfig.bMemstat ){
000529 sqlite3_int64 nUsed;
000530 sqlite3_mutex_enter(mem0.mutex);
000531 sqlite3StatusHighwater(SQLITE_STATUS_MALLOC_SIZE, (int)nBytes);
000532 nDiff = nNew - nOld;
000533 if( nDiff>0 && (nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED)) >=
000534 mem0.alarmThreshold-nDiff ){
000535 sqlite3MallocAlarm(nDiff);
000536 if( mem0.hardLimit>0 && nUsed >= mem0.hardLimit - nDiff ){
000537 sqlite3_mutex_leave(mem0.mutex);
000538 return 0;
000539 }
000540 }
000541 pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
000542 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
000543 if( pNew==0 && mem0.alarmThreshold>0 ){
000544 sqlite3MallocAlarm((int)nBytes);
000545 pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
000546 }
000547 #endif
000548 if( pNew ){
000549 nNew = sqlite3MallocSize(pNew);
000550 sqlite3StatusUp(SQLITE_STATUS_MEMORY_USED, nNew-nOld);
000551 }
000552 sqlite3_mutex_leave(mem0.mutex);
000553 }else{
000554 pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);
000555 }
000556 assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-11148-40995 */
000557 return pNew;
000558 }
000559
000560 /*
000561 ** The public interface to sqlite3Realloc. Make sure that the memory
000562 ** subsystem is initialized prior to invoking sqliteRealloc.
000563 */
000564 void *sqlite3_realloc(void *pOld, int n){
000565 #ifndef SQLITE_OMIT_AUTOINIT
000566 if( sqlite3_initialize() ) return 0;
000567 #endif
000568 if( n<0 ) n = 0; /* IMP: R-26507-47431 */
000569 return sqlite3Realloc(pOld, n);
000570 }
000571 void *sqlite3_realloc64(void *pOld, sqlite3_uint64 n){
000572 #ifndef SQLITE_OMIT_AUTOINIT
000573 if( sqlite3_initialize() ) return 0;
000574 #endif
000575 return sqlite3Realloc(pOld, n);
000576 }
000577
000578
000579 /*
000580 ** Allocate and zero memory.
000581 */
000582 void *sqlite3MallocZero(u64 n){
000583 void *p = sqlite3Malloc(n);
000584 if( p ){
000585 memset(p, 0, (size_t)n);
000586 }
000587 return p;
000588 }
000589
000590 /*
000591 ** Allocate and zero memory. If the allocation fails, make
000592 ** the mallocFailed flag in the connection pointer.
000593 */
000594 void *sqlite3DbMallocZero(sqlite3 *db, u64 n){
000595 void *p;
000596 testcase( db==0 );
000597 p = sqlite3DbMallocRaw(db, n);
000598 if( p ) memset(p, 0, (size_t)n);
000599 return p;
000600 }
000601
000602
000603 /* Finish the work of sqlite3DbMallocRawNN for the unusual and
000604 ** slower case when the allocation cannot be fulfilled using lookaside.
000605 */
000606 static SQLITE_NOINLINE void *dbMallocRawFinish(sqlite3 *db, u64 n){
000607 void *p;
000608 assert( db!=0 );
000609 p = sqlite3Malloc(n);
000610 if( !p ) sqlite3OomFault(db);
000611 sqlite3MemdebugSetType(p,
000612 (db->lookaside.bDisable==0) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP);
000613 return p;
000614 }
000615
000616 /*
000617 ** Allocate memory, either lookaside (if possible) or heap.
000618 ** If the allocation fails, set the mallocFailed flag in
000619 ** the connection pointer.
000620 **
000621 ** If db!=0 and db->mallocFailed is true (indicating a prior malloc
000622 ** failure on the same database connection) then always return 0.
000623 ** Hence for a particular database connection, once malloc starts
000624 ** failing, it fails consistently until mallocFailed is reset.
000625 ** This is an important assumption. There are many places in the
000626 ** code that do things like this:
000627 **
000628 ** int *a = (int*)sqlite3DbMallocRaw(db, 100);
000629 ** int *b = (int*)sqlite3DbMallocRaw(db, 200);
000630 ** if( b ) a[10] = 9;
000631 **
000632 ** In other words, if a subsequent malloc (ex: "b") worked, it is assumed
000633 ** that all prior mallocs (ex: "a") worked too.
000634 **
000635 ** The sqlite3MallocRawNN() variant guarantees that the "db" parameter is
000636 ** not a NULL pointer.
000637 */
000638 void *sqlite3DbMallocRaw(sqlite3 *db, u64 n){
000639 void *p;
000640 if( db ) return sqlite3DbMallocRawNN(db, n);
000641 p = sqlite3Malloc(n);
000642 sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
000643 return p;
000644 }
000645 void *sqlite3DbMallocRawNN(sqlite3 *db, u64 n){
000646 #ifndef SQLITE_OMIT_LOOKASIDE
000647 LookasideSlot *pBuf;
000648 assert( db!=0 );
000649 assert( sqlite3_mutex_held(db->mutex) );
000650 assert( db->pnBytesFreed==0 );
000651 if( n>db->lookaside.sz ){
000652 if( !db->lookaside.bDisable ){
000653 db->lookaside.anStat[1]++;
000654 }else if( db->mallocFailed ){
000655 return 0;
000656 }
000657 return dbMallocRawFinish(db, n);
000658 }
000659 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000660 if( n<=LOOKASIDE_SMALL ){
000661 if( (pBuf = db->lookaside.pSmallFree)!=0 ){
000662 db->lookaside.pSmallFree = pBuf->pNext;
000663 db->lookaside.anStat[0]++;
000664 return (void*)pBuf;
000665 }else if( (pBuf = db->lookaside.pSmallInit)!=0 ){
000666 db->lookaside.pSmallInit = pBuf->pNext;
000667 db->lookaside.anStat[0]++;
000668 return (void*)pBuf;
000669 }
000670 }
000671 #endif
000672 if( (pBuf = db->lookaside.pFree)!=0 ){
000673 db->lookaside.pFree = pBuf->pNext;
000674 db->lookaside.anStat[0]++;
000675 return (void*)pBuf;
000676 }else if( (pBuf = db->lookaside.pInit)!=0 ){
000677 db->lookaside.pInit = pBuf->pNext;
000678 db->lookaside.anStat[0]++;
000679 return (void*)pBuf;
000680 }else{
000681 db->lookaside.anStat[2]++;
000682 }
000683 #else
000684 assert( db!=0 );
000685 assert( sqlite3_mutex_held(db->mutex) );
000686 assert( db->pnBytesFreed==0 );
000687 if( db->mallocFailed ){
000688 return 0;
000689 }
000690 #endif
000691 return dbMallocRawFinish(db, n);
000692 }
000693
000694 /* Forward declaration */
000695 static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n);
000696
000697 /*
000698 ** Resize the block of memory pointed to by p to n bytes. If the
000699 ** resize fails, set the mallocFailed flag in the connection object.
000700 */
000701 void *sqlite3DbRealloc(sqlite3 *db, void *p, u64 n){
000702 assert( db!=0 );
000703 if( p==0 ) return sqlite3DbMallocRawNN(db, n);
000704 assert( sqlite3_mutex_held(db->mutex) );
000705 if( ((uptr)p)<(uptr)db->lookaside.pEnd ){
000706 #ifndef SQLITE_OMIT_TWOSIZE_LOOKASIDE
000707 if( ((uptr)p)>=(uptr)db->lookaside.pMiddle ){
000708 if( n<=LOOKASIDE_SMALL ) return p;
000709 }else
000710 #endif
000711 if( ((uptr)p)>=(uptr)db->lookaside.pStart ){
000712 if( n<=db->lookaside.szTrue ) return p;
000713 }
000714 }
000715 return dbReallocFinish(db, p, n);
000716 }
000717 static SQLITE_NOINLINE void *dbReallocFinish(sqlite3 *db, void *p, u64 n){
000718 void *pNew = 0;
000719 assert( db!=0 );
000720 assert( p!=0 );
000721 if( db->mallocFailed==0 ){
000722 if( isLookaside(db, p) ){
000723 pNew = sqlite3DbMallocRawNN(db, n);
000724 if( pNew ){
000725 memcpy(pNew, p, lookasideMallocSize(db, p));
000726 sqlite3DbFree(db, p);
000727 }
000728 }else{
000729 assert( sqlite3MemdebugHasType(p, (MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000730 assert( sqlite3MemdebugNoType(p, (u8)~(MEMTYPE_LOOKASIDE|MEMTYPE_HEAP)) );
000731 sqlite3MemdebugSetType(p, MEMTYPE_HEAP);
000732 pNew = sqlite3Realloc(p, n);
000733 if( !pNew ){
000734 sqlite3OomFault(db);
000735 }
000736 sqlite3MemdebugSetType(pNew,
000737 (db->lookaside.bDisable==0 ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));
000738 }
000739 }
000740 return pNew;
000741 }
000742
000743 /*
000744 ** Attempt to reallocate p. If the reallocation fails, then free p
000745 ** and set the mallocFailed flag in the database connection.
000746 */
000747 void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, u64 n){
000748 void *pNew;
000749 pNew = sqlite3DbRealloc(db, p, n);
000750 if( !pNew ){
000751 sqlite3DbFree(db, p);
000752 }
000753 return pNew;
000754 }
000755
000756 /*
000757 ** Make a copy of a string in memory obtained from sqliteMalloc(). These
000758 ** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This
000759 ** is because when memory debugging is turned on, these two functions are
000760 ** called via macros that record the current file and line number in the
000761 ** ThreadData structure.
000762 */
000763 char *sqlite3DbStrDup(sqlite3 *db, const char *z){
000764 char *zNew;
000765 size_t n;
000766 if( z==0 ){
000767 return 0;
000768 }
000769 n = strlen(z) + 1;
000770 zNew = sqlite3DbMallocRaw(db, n);
000771 if( zNew ){
000772 memcpy(zNew, z, n);
000773 }
000774 return zNew;
000775 }
000776 char *sqlite3DbStrNDup(sqlite3 *db, const char *z, u64 n){
000777 char *zNew;
000778 assert( db!=0 );
000779 assert( z!=0 || n==0 );
000780 assert( (n&0x7fffffff)==n );
000781 zNew = z ? sqlite3DbMallocRawNN(db, n+1) : 0;
000782 if( zNew ){
000783 memcpy(zNew, z, (size_t)n);
000784 zNew[n] = 0;
000785 }
000786 return zNew;
000787 }
000788
000789 /*
000790 ** The text between zStart and zEnd represents a phrase within a larger
000791 ** SQL statement. Make a copy of this phrase in space obtained form
000792 ** sqlite3DbMalloc(). Omit leading and trailing whitespace.
000793 */
000794 char *sqlite3DbSpanDup(sqlite3 *db, const char *zStart, const char *zEnd){
000795 int n;
000796 #ifdef SQLITE_DEBUG
000797 /* Because of the way the parser works, the span is guaranteed to contain
000798 ** at least one non-space character */
000799 for(n=0; sqlite3Isspace(zStart[n]); n++){ assert( &zStart[n]<zEnd ); }
000800 #endif
000801 while( sqlite3Isspace(zStart[0]) ) zStart++;
000802 n = (int)(zEnd - zStart);
000803 while( sqlite3Isspace(zStart[n-1]) ) n--;
000804 return sqlite3DbStrNDup(db, zStart, n);
000805 }
000806
000807 /*
000808 ** Free any prior content in *pz and replace it with a copy of zNew.
000809 */
000810 void sqlite3SetString(char **pz, sqlite3 *db, const char *zNew){
000811 char *z = sqlite3DbStrDup(db, zNew);
000812 sqlite3DbFree(db, *pz);
000813 *pz = z;
000814 }
000815
000816 /*
000817 ** Call this routine to record the fact that an OOM (out-of-memory) error
000818 ** has happened. This routine will set db->mallocFailed, and also
000819 ** temporarily disable the lookaside memory allocator and interrupt
000820 ** any running VDBEs.
000821 **
000822 ** Always return a NULL pointer so that this routine can be invoked using
000823 **
000824 ** return sqlite3OomFault(db);
000825 **
000826 ** and thereby avoid unnecessary stack frame allocations for the overwhelmingly
000827 ** common case where no OOM occurs.
000828 */
000829 void *sqlite3OomFault(sqlite3 *db){
000830 if( db->mallocFailed==0 && db->bBenignMalloc==0 ){
000831 db->mallocFailed = 1;
000832 if( db->nVdbeExec>0 ){
000833 AtomicStore(&db->u1.isInterrupted, 1);
000834 }
000835 DisableLookaside;
000836 if( db->pParse ){
000837 Parse *pParse;
000838 sqlite3ErrorMsg(db->pParse, "out of memory");
000839 db->pParse->rc = SQLITE_NOMEM_BKPT;
000840 for(pParse=db->pParse->pOuterParse; pParse; pParse = pParse->pOuterParse){
000841 pParse->nErr++;
000842 pParse->rc = SQLITE_NOMEM;
000843 }
000844 }
000845 }
000846 return 0;
000847 }
000848
000849 /*
000850 ** This routine reactivates the memory allocator and clears the
000851 ** db->mallocFailed flag as necessary.
000852 **
000853 ** The memory allocator is not restarted if there are running
000854 ** VDBEs.
000855 */
000856 void sqlite3OomClear(sqlite3 *db){
000857 if( db->mallocFailed && db->nVdbeExec==0 ){
000858 db->mallocFailed = 0;
000859 AtomicStore(&db->u1.isInterrupted, 0);
000860 assert( db->lookaside.bDisable>0 );
000861 EnableLookaside;
000862 }
000863 }
000864
000865 /*
000866 ** Take actions at the end of an API call to deal with error codes.
000867 */
000868 static SQLITE_NOINLINE int apiHandleError(sqlite3 *db, int rc){
000869 if( db->mallocFailed || rc==SQLITE_IOERR_NOMEM ){
000870 sqlite3OomClear(db);
000871 sqlite3Error(db, SQLITE_NOMEM);
000872 return SQLITE_NOMEM_BKPT;
000873 }
000874 return rc & db->errMask;
000875 }
000876
000877 /*
000878 ** This function must be called before exiting any API function (i.e.
000879 ** returning control to the user) that has called sqlite3_malloc or
000880 ** sqlite3_realloc.
000881 **
000882 ** The returned value is normally a copy of the second argument to this
000883 ** function. However, if a malloc() failure has occurred since the previous
000884 ** invocation SQLITE_NOMEM is returned instead.
000885 **
000886 ** If an OOM as occurred, then the connection error-code (the value
000887 ** returned by sqlite3_errcode()) is set to SQLITE_NOMEM.
000888 */
000889 int sqlite3ApiExit(sqlite3* db, int rc){
000890 /* If the db handle must hold the connection handle mutex here.
000891 ** Otherwise the read (and possible write) of db->mallocFailed
000892 ** is unsafe, as is the call to sqlite3Error().
000893 */
000894 assert( db!=0 );
000895 assert( sqlite3_mutex_held(db->mutex) );
000896 if( db->mallocFailed || rc ){
000897 return apiHandleError(db, rc);
000898 }
000899 return rc & db->errMask;
000900 }