sqlcipher/src/malloc.c at sqlite-release · PHPDOTSQL/sqlcipher · GitHub

History

782 lines (736 loc) · 22.5 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

677

678

679

680

681

682

683

684

685

686

687

688

689

690

691

692

693

694

695

696

697

698

699

700

701

702

703

704

705

706

707

708

709

710

711

712

713

714

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

** 2001 September 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.

*************************************************************************

** Memory allocation functions used throughout sqlite.

#include "sqliteInt.h"

#include <stdarg.h>

** Attempt to release up to n bytes of non-essential memory currently

** held by SQLite. An example of non-essential memory is memory used to

** cache database pages that are not currently in use.

int sqlite3_release_memory(int n){

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

return sqlite3PcacheReleaseMemory(n);

#else

/* IMPLEMENTATION-OF: R-34391-24921 The sqlite3_release_memory() routine

** is a no-op returning zero if SQLite is not compiled with

** SQLITE_ENABLE_MEMORY_MANAGEMENT. */

UNUSED_PARAMETER(n);

return 0;

#endif

}

** An instance of the following object records the location of

** each unused scratch buffer.

typedef struct ScratchFreeslot {

struct ScratchFreeslot *pNext; /* Next unused scratch buffer */

} ScratchFreeslot;

** State information local to the memory allocation subsystem.

static SQLITE_WSD struct Mem0Global {

sqlite3_mutex *mutex; /* Mutex to serialize access */

** The alarm callback and its arguments. The mem0.mutex lock will

** be held while the callback is running. Recursive calls into

** the memory subsystem are allowed, but no new callbacks will be

** issued.

sqlite3_int64 alarmThreshold;

void (*alarmCallback)(void*, sqlite3_int64,int);

void *alarmArg;

** Pointers to the end of sqlite3GlobalConfig.pScratch memory

** (so that a range test can be used to determine if an allocation

** being freed came from pScratch) and a pointer to the list of

** unused scratch allocations.

void *pScratchEnd;

ScratchFreeslot *pScratchFree;

u32 nScratchFree;

** True if heap is nearly "full" where "full" is defined by the

** sqlite3_soft_heap_limit() setting.

int nearlyFull;

} mem0 = { 0, 0, 0, 0, 0, 0, 0, 0 };

#define mem0 GLOBAL(struct Mem0Global, mem0)

** This routine runs when the memory allocator sees that the

** total memory allocation is about to exceed the soft heap

** limit.

static void softHeapLimitEnforcer(

void *NotUsed,

sqlite3_int64 NotUsed2,

int allocSize

){

UNUSED_PARAMETER2(NotUsed, NotUsed2);

sqlite3_release_memory(allocSize);

}

** Change the alarm callback

static int sqlite3MemoryAlarm(

void(*xCallback)(void *pArg, sqlite3_int64 used,int N),

void *pArg,

sqlite3_int64 iThreshold

){

int nUsed;

sqlite3_mutex_enter(mem0.mutex);

mem0.alarmCallback = xCallback;

mem0.alarmArg = pArg;

mem0.alarmThreshold = iThreshold;

nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);

sqlite3_mutex_leave(mem0.mutex);

return SQLITE_OK;

}

#ifndef SQLITE_OMIT_DEPRECATED

** Deprecated external interface. Internal/core SQLite code

** should call sqlite3MemoryAlarm.

int sqlite3_memory_alarm(

void(*xCallback)(void *pArg, sqlite3_int64 used,int N),

void *pArg,

sqlite3_int64 iThreshold

){

return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);

}

#endif

** Set the soft heap-size limit for the library. Passing a zero or

** negative value indicates no limit.

sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){

sqlite3_int64 priorLimit;

sqlite3_int64 excess;

#ifndef SQLITE_OMIT_AUTOINIT

int rc = sqlite3_initialize();

if( rc ) return -1;

#endif

sqlite3_mutex_enter(mem0.mutex);

priorLimit = mem0.alarmThreshold;

sqlite3_mutex_leave(mem0.mutex);

if( n<0 ) return priorLimit;

if( n>0 ){

sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);

}else{

sqlite3MemoryAlarm(0, 0, 0);

}

excess = sqlite3_memory_used() - n;

if( excess>0 ) sqlite3_release_memory((int)(excess & 0x7fffffff));

return priorLimit;

}

void sqlite3_soft_heap_limit(int n){

if( n<0 ) n = 0;

sqlite3_soft_heap_limit64(n);

}

** Initialize the memory allocation subsystem.

int sqlite3MallocInit(void){

if( sqlite3GlobalConfig.m.xMalloc==0 ){

sqlite3MemSetDefault();

}

memset(&mem0, 0, sizeof(mem0));

if( sqlite3GlobalConfig.bCoreMutex ){

mem0.mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MEM);

}

if( sqlite3GlobalConfig.pScratch && sqlite3GlobalConfig.szScratch>=100

&& sqlite3GlobalConfig.nScratch>0 ){

int i, n, sz;

ScratchFreeslot *pSlot;

sz = ROUNDDOWN8(sqlite3GlobalConfig.szScratch);

sqlite3GlobalConfig.szScratch = sz;

pSlot = (ScratchFreeslot*)sqlite3GlobalConfig.pScratch;

n = sqlite3GlobalConfig.nScratch;

mem0.pScratchFree = pSlot;

mem0.nScratchFree = n;

for(i=0; i<n-1; i++){

pSlot->pNext = (ScratchFreeslot*)(sz+(char*)pSlot);

pSlot = pSlot->pNext;

}

pSlot->pNext = 0;

mem0.pScratchEnd = (void*)&pSlot[1];

}else{

mem0.pScratchEnd = 0;

sqlite3GlobalConfig.pScratch = 0;

sqlite3GlobalConfig.szScratch = 0;

sqlite3GlobalConfig.nScratch = 0;

}

if( sqlite3GlobalConfig.pPage==0 || sqlite3GlobalConfig.szPage<512

|| sqlite3GlobalConfig.nPage<1 ){

sqlite3GlobalConfig.pPage = 0;

sqlite3GlobalConfig.szPage = 0;

sqlite3GlobalConfig.nPage = 0;

}

return sqlite3GlobalConfig.m.xInit(sqlite3GlobalConfig.m.pAppData);

}

** Return true if the heap is currently under memory pressure - in other

** words if the amount of heap used is close to the limit set by

** sqlite3_soft_heap_limit().

int sqlite3HeapNearlyFull(void){

return mem0.nearlyFull;

}

** Deinitialize the memory allocation subsystem.

void sqlite3MallocEnd(void){

if( sqlite3GlobalConfig.m.xShutdown ){

sqlite3GlobalConfig.m.xShutdown(sqlite3GlobalConfig.m.pAppData);

}

memset(&mem0, 0, sizeof(mem0));

}

** Return the amount of memory currently checked out.

sqlite3_int64 sqlite3_memory_used(void){

int n, mx;

sqlite3_int64 res;

sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, 0);

res = (sqlite3_int64)n; /* Work around bug in Borland C. Ticket #3216 */

return res;

}

** Return the maximum amount of memory that has ever been

** checked out since either the beginning of this process

** or since the most recent reset.

sqlite3_int64 sqlite3_memory_highwater(int resetFlag){

int n, mx;

sqlite3_int64 res;

sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, resetFlag);

res = (sqlite3_int64)mx; /* Work around bug in Borland C. Ticket #3216 */

return res;

}

** Trigger the alarm

static void sqlite3MallocAlarm(int nByte){

void (*xCallback)(void*,sqlite3_int64,int);

sqlite3_int64 nowUsed;

void *pArg;

if( mem0.alarmCallback==0 ) return;

xCallback = mem0.alarmCallback;

nowUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

pArg = mem0.alarmArg;

mem0.alarmCallback = 0;

sqlite3_mutex_leave(mem0.mutex);

xCallback(pArg, nowUsed, nByte);

sqlite3_mutex_enter(mem0.mutex);

mem0.alarmCallback = xCallback;

mem0.alarmArg = pArg;

}

** Do a memory allocation with statistics and alarms. Assume the

** lock is already held.

static int mallocWithAlarm(int n, void **pp){

int nFull;

void *p;

assert( sqlite3_mutex_held(mem0.mutex) );

nFull = sqlite3GlobalConfig.m.xRoundup(n);

sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, n);

if( mem0.alarmCallback!=0 ){

int nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);

if( nUsed >= mem0.alarmThreshold - nFull ){

mem0.nearlyFull = 1;

sqlite3MallocAlarm(nFull);

}else{

mem0.nearlyFull = 0;

}

p = sqlite3GlobalConfig.m.xMalloc(nFull);

#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT

if( p==0 && mem0.alarmCallback ){

sqlite3MallocAlarm(nFull);

p = sqlite3GlobalConfig.m.xMalloc(nFull);

}

#endif

if( p ){

nFull = sqlite3MallocSize(p);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nFull);

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, 1);

}

*pp = p;

return nFull;

}

** Allocate memory. This routine is like sqlite3_malloc() except that it

** assumes the memory subsystem has already been initialized.

void *sqlite3Malloc(int n){

void *p;

if( n<=0 /* IMP: R-65312-04917 */

|| n>=0x7fffff00

){

/* A memory allocation of a number of bytes which is near the maximum

** signed integer value might cause an integer overflow inside of the

** xMalloc(). Hence we limit the maximum size to 0x7fffff00, giving

** 255 bytes of overhead. SQLite itself will never use anything near

** this amount. The only way to reach the limit is with sqlite3_malloc() */

p = 0;

}else if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

mallocWithAlarm(n, &p);

sqlite3_mutex_leave(mem0.mutex);

}else{

p = sqlite3GlobalConfig.m.xMalloc(n);

}

assert( EIGHT_BYTE_ALIGNMENT(p) ); /* IMP: R-04675-44850 */

return p;

}

** This version of the memory allocation is for use by the application.

** First make sure the memory subsystem is initialized, then do the

** allocation.

void *sqlite3_malloc(int n){

#ifndef SQLITE_OMIT_AUTOINIT

if( sqlite3_initialize() ) return 0;

#endif

return sqlite3Malloc(n);

}

** Each thread may only have a single outstanding allocation from

** xScratchMalloc(). We verify this constraint in the single-threaded

** case by setting scratchAllocOut to 1 when an allocation

** is outstanding clearing it when the allocation is freed.

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

static int scratchAllocOut = 0;

#endif

** Allocate memory that is to be used and released right away.

** This routine is similar to alloca() in that it is not intended

** for situations where the memory might be held long-term. This

** routine is intended to get memory to old large transient data

** structures that would not normally fit on the stack of an

** embedded processor.

void *sqlite3ScratchMalloc(int n){

void *p;

assert( n>0 );

sqlite3_mutex_enter(mem0.mutex);

if( mem0.nScratchFree && sqlite3GlobalConfig.szScratch>=n ){

p = mem0.pScratchFree;

mem0.pScratchFree = mem0.pScratchFree->pNext;

mem0.nScratchFree--;

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, 1);

sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);

sqlite3_mutex_leave(mem0.mutex);

}else{

if( sqlite3GlobalConfig.bMemstat ){

sqlite3StatusSet(SQLITE_STATUS_SCRATCH_SIZE, n);

n = mallocWithAlarm(n, &p);

if( p ) sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, n);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3_mutex_leave(mem0.mutex);

p = sqlite3GlobalConfig.m.xMalloc(n);

}

sqlite3MemdebugSetType(p, MEMTYPE_SCRATCH);

}

assert( sqlite3_mutex_notheld(mem0.mutex) );

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

/* Verify that no more than two scratch allocations per thread

** are outstanding at one time. (This is only checked in the

** single-threaded case since checking in the multi-threaded case

** would be much more complicated.) */

assert( scratchAllocOut<=1 );

if( p ) scratchAllocOut++;

#endif

return p;

}

void sqlite3ScratchFree(void *p){

if( p ){

#if SQLITE_THREADSAFE==0 && !defined(NDEBUG)

/* Verify that no more than two scratch allocation per thread

** is outstanding at one time. (This is only checked in the

** single-threaded case since checking in the multi-threaded case

** would be much more complicated.) */

assert( scratchAllocOut>=1 && scratchAllocOut<=2 );

scratchAllocOut--;

#endif

if( p>=sqlite3GlobalConfig.pScratch && p<mem0.pScratchEnd ){

/* Release memory from the SQLITE_CONFIG_SCRATCH allocation */

ScratchFreeslot *pSlot;

pSlot = (ScratchFreeslot*)p;

sqlite3_mutex_enter(mem0.mutex);

pSlot->pNext = mem0.pScratchFree;

mem0.pScratchFree = pSlot;

mem0.nScratchFree++;

assert( mem0.nScratchFree <= (u32)sqlite3GlobalConfig.nScratch );

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_USED, -1);

sqlite3_mutex_leave(mem0.mutex);

}else{

/* Release memory back to the heap */

assert( sqlite3MemdebugHasType(p, MEMTYPE_SCRATCH) );

assert( sqlite3MemdebugNoType(p, ~MEMTYPE_SCRATCH) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

if( sqlite3GlobalConfig.bMemstat ){

int iSize = sqlite3MallocSize(p);

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusAdd(SQLITE_STATUS_SCRATCH_OVERFLOW, -iSize);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -iSize);

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);

sqlite3GlobalConfig.m.xFree(p);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3GlobalConfig.m.xFree(p);

}

** TRUE if p is a lookaside memory allocation from db

#ifndef SQLITE_OMIT_LOOKASIDE

static int isLookaside(sqlite3 *db, void *p){

return p && p>=db->lookaside.pStart && p<db->lookaside.pEnd;

}

#else

#define isLookaside(A,B) 0

#endif

** Return the size of a memory allocation previously obtained from

** sqlite3Malloc() or sqlite3_malloc().

int sqlite3MallocSize(void *p){

assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );

return sqlite3GlobalConfig.m.xSize(p);

}

int sqlite3DbMallocSize(sqlite3 *db, void *p){

assert( db==0 || sqlite3_mutex_held(db->mutex) );

if( db && isLookaside(db, p) ){

return db->lookaside.sz;

}else{

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );

return sqlite3GlobalConfig.m.xSize(p);

}

** Free memory previously obtained from sqlite3Malloc().

void sqlite3_free(void *p){

if( p==0 ) return; /* IMP: R-49053-54554 */

assert( sqlite3MemdebugNoType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_HEAP) );

if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, -sqlite3MallocSize(p));

sqlite3StatusAdd(SQLITE_STATUS_MALLOC_COUNT, -1);

sqlite3GlobalConfig.m.xFree(p);

sqlite3_mutex_leave(mem0.mutex);

}else{

sqlite3GlobalConfig.m.xFree(p);

}

** Free memory that might be associated with a particular database

** connection.

void sqlite3DbFree(sqlite3 *db, void *p){

assert( db==0 || sqlite3_mutex_held(db->mutex) );

if( db ){

if( db->pnBytesFreed ){

*db->pnBytesFreed += sqlite3DbMallocSize(db, p);

return;

}

if( isLookaside(db, p) ){

LookasideSlot *pBuf = (LookasideSlot*)p;

#if SQLITE_DEBUG

/* Trash all content in the buffer being freed */

memset(p, 0xaa, db->lookaside.sz);

#endif

pBuf->pNext = db->lookaside.pFree;

db->lookaside.pFree = pBuf;

db->lookaside.nOut--;

return;

}

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

assert( db!=0 || sqlite3MemdebugNoType(p, MEMTYPE_LOOKASIDE) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

sqlite3_free(p);

}

** Change the size of an existing memory allocation

void *sqlite3Realloc(void *pOld, int nBytes){

int nOld, nNew, nDiff;

void *pNew;

if( pOld==0 ){

return sqlite3Malloc(nBytes); /* IMP: R-28354-25769 */

}

if( nBytes<=0 ){

sqlite3_free(pOld); /* IMP: R-31593-10574 */

return 0;

}

if( nBytes>=0x7fffff00 ){

/* The 0x7ffff00 limit term is explained in comments on sqlite3Malloc() */

return 0;

}

nOld = sqlite3MallocSize(pOld);

/* IMPLEMENTATION-OF: R-46199-30249 SQLite guarantees that the second

** argument to xRealloc is always a value returned by a prior call to

** xRoundup. */

nNew = sqlite3GlobalConfig.m.xRoundup(nBytes);

if( nOld==nNew ){

pNew = pOld;

}else if( sqlite3GlobalConfig.bMemstat ){

sqlite3_mutex_enter(mem0.mutex);

sqlite3StatusSet(SQLITE_STATUS_MALLOC_SIZE, nBytes);

nDiff = nNew - nOld;

if( sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED) >=

mem0.alarmThreshold-nDiff ){

sqlite3MallocAlarm(nDiff);

}

assert( sqlite3MemdebugHasType(pOld, MEMTYPE_HEAP) );

assert( sqlite3MemdebugNoType(pOld, ~MEMTYPE_HEAP) );

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

if( pNew==0 && mem0.alarmCallback ){

sqlite3MallocAlarm(nBytes);

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

}

if( pNew ){

nNew = sqlite3MallocSize(pNew);

sqlite3StatusAdd(SQLITE_STATUS_MEMORY_USED, nNew-nOld);

}

sqlite3_mutex_leave(mem0.mutex);

}else{

pNew = sqlite3GlobalConfig.m.xRealloc(pOld, nNew);

}

assert( EIGHT_BYTE_ALIGNMENT(pNew) ); /* IMP: R-04675-44850 */

return pNew;

}

** The public interface to sqlite3Realloc. Make sure that the memory

** subsystem is initialized prior to invoking sqliteRealloc.

void *sqlite3_realloc(void *pOld, int n){

#ifndef SQLITE_OMIT_AUTOINIT

if( sqlite3_initialize() ) return 0;

#endif

return sqlite3Realloc(pOld, n);

}

** Allocate and zero memory.

void *sqlite3MallocZero(int n){

void *p = sqlite3Malloc(n);

if( p ){

memset(p, 0, n);

}

return p;

}

** Allocate and zero memory. If the allocation fails, make

** the mallocFailed flag in the connection pointer.

void *sqlite3DbMallocZero(sqlite3 *db, int n){

void *p = sqlite3DbMallocRaw(db, n);

if( p ){

memset(p, 0, n);

}

return p;

}

** Allocate and zero memory. If the allocation fails, make

** the mallocFailed flag in the connection pointer.

** If db!=0 and db->mallocFailed is true (indicating a prior malloc

** failure on the same database connection) then always return 0.

** Hence for a particular database connection, once malloc starts

** failing, it fails consistently until mallocFailed is reset.

** This is an important assumption. There are many places in the

** code that do things like this:

** int *a = (int*)sqlite3DbMallocRaw(db, 100);

** int *b = (int*)sqlite3DbMallocRaw(db, 200);

** if( b ) a[10] = 9;

** In other words, if a subsequent malloc (ex: "b") worked, it is assumed

** that all prior mallocs (ex: "a") worked too.

void *sqlite3DbMallocRaw(sqlite3 *db, int n){

void *p;

assert( db==0 || sqlite3_mutex_held(db->mutex) );

assert( db==0 || db->pnBytesFreed==0 );

#ifndef SQLITE_OMIT_LOOKASIDE

if( db ){

LookasideSlot *pBuf;

if( db->mallocFailed ){

return 0;

}

if( db->lookaside.bEnabled ){

if( n>db->lookaside.sz ){

db->lookaside.anStat[1]++;

}else if( (pBuf = db->lookaside.pFree)==0 ){

db->lookaside.anStat[2]++;

}else{

db->lookaside.pFree = pBuf->pNext;

db->lookaside.nOut++;

db->lookaside.anStat[0]++;

if( db->lookaside.nOut>db->lookaside.mxOut ){

db->lookaside.mxOut = db->lookaside.nOut;

}

return (void*)pBuf;

}

#else

if( db && db->mallocFailed ){

return 0;

}

#endif

p = sqlite3Malloc(n);

if( !p && db ){

db->mallocFailed = 1;

}

sqlite3MemdebugSetType(p, MEMTYPE_DB |

((db && db->lookaside.bEnabled) ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));

return p;

}

** Resize the block of memory pointed to by p to n bytes. If the

** resize fails, set the mallocFailed flag in the connection object.

void *sqlite3DbRealloc(sqlite3 *db, void *p, int n){

void *pNew = 0;

assert( db!=0 );

assert( sqlite3_mutex_held(db->mutex) );

if( db->mallocFailed==0 ){

if( p==0 ){

return sqlite3DbMallocRaw(db, n);

}

if( isLookaside(db, p) ){

if( n<=db->lookaside.sz ){

return p;

}

pNew = sqlite3DbMallocRaw(db, n);

if( pNew ){

memcpy(pNew, p, db->lookaside.sz);

sqlite3DbFree(db, p);

}

}else{

assert( sqlite3MemdebugHasType(p, MEMTYPE_DB) );

assert( sqlite3MemdebugHasType(p, MEMTYPE_LOOKASIDE|MEMTYPE_HEAP) );

sqlite3MemdebugSetType(p, MEMTYPE_HEAP);

pNew = sqlite3_realloc(p, n);

if( !pNew ){

sqlite3MemdebugSetType(p, MEMTYPE_DB|MEMTYPE_HEAP);

db->mallocFailed = 1;

}

sqlite3MemdebugSetType(pNew, MEMTYPE_DB |

(db->lookaside.bEnabled ? MEMTYPE_LOOKASIDE : MEMTYPE_HEAP));

}

return pNew;

}

** Attempt to reallocate p. If the reallocation fails, then free p

** and set the mallocFailed flag in the database connection.

void *sqlite3DbReallocOrFree(sqlite3 *db, void *p, int n){

void *pNew;

pNew = sqlite3DbRealloc(db, p, n);

if( !pNew ){

sqlite3DbFree(db, p);

}

return pNew;

}

** Make a copy of a string in memory obtained from sqliteMalloc(). These

** functions call sqlite3MallocRaw() directly instead of sqliteMalloc(). This

** is because when memory debugging is turned on, these two functions are

** called via macros that record the current file and line number in the

** ThreadData structure.

char *sqlite3DbStrDup(sqlite3 *db, const char *z){

char *zNew;

size_t n;

if( z==0 ){

return 0;

}

n = sqlite3Strlen30(z) + 1;

assert( (n&0x7fffffff)==n );

zNew = sqlite3DbMallocRaw(db, (int)n);

if( zNew ){

memcpy(zNew, z, n);

}

return zNew;

}

char *sqlite3DbStrNDup(sqlite3 *db, const char *z, int n){

char *zNew;

if( z==0 ){

return 0;

}

assert( (n&0x7fffffff)==n );

zNew = sqlite3DbMallocRaw(db, n+1);

if( zNew ){

memcpy(zNew, z, n);

zNew[n] = 0;

}

return zNew;

}

** Create a string from the zFromat argument and the va_list that follows.

** Store the string in memory obtained from sqliteMalloc() and make *pz

** point to that string.

void sqlite3SetString(char **pz, sqlite3 *db, const char *zFormat, ...){

va_list ap;

char *z;

va_start(ap, zFormat);

z = sqlite3VMPrintf(db, zFormat, ap);

va_end(ap);

sqlite3DbFree(db, *pz);

*pz = z;

}

** This function must be called before exiting any API function (i.e.

** returning control to the user) that has called sqlite3_malloc or

** sqlite3_realloc.

** The returned value is normally a copy of the second argument to this

** function. However, if a malloc() failure has occurred since the previous

** invocation SQLITE_NOMEM is returned instead.

** If the first argument, db, is not NULL and a malloc() error has occurred,

** then the connection error-code (the value returned by sqlite3_errcode())

** is set to SQLITE_NOMEM.

int sqlite3ApiExit(sqlite3* db, int rc){

/* If the db handle is not NULL, then we must hold the connection handle

** mutex here. Otherwise the read (and possible write) of db->mallocFailed

** is unsafe, as is the call to sqlite3Error().

assert( !db || sqlite3_mutex_held(db->mutex) );

if( db && (db->mallocFailed || rc==SQLITE_IOERR_NOMEM) ){

sqlite3Error(db, SQLITE_NOMEM, 0);

db->mallocFailed = 0;

rc = SQLITE_NOMEM;

}

return rc & (db ? db->errMask : 0xff);

}

sqlcipher/src/malloc.c at sqlite-release · PHPDOTSQL/sqlcipher · GitHub

Expand file tree

Breadcrumbs

malloc.c

Latest commit

History

Breadcrumbs

malloc.c

File metadata and controls