000001 /*
000002 ** 2005 November 29
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 ** This file contains OS interface code that is common to all
000014 ** architectures.
000015 */
000016 #include "sqliteInt.h"
000017
000018 /*
000019 ** If we compile with the SQLITE_TEST macro set, then the following block
000020 ** of code will give us the ability to simulate a disk I/O error. This
000021 ** is used for testing the I/O recovery logic.
000022 */
000023 #if defined(SQLITE_TEST)
000024 int sqlite3_io_error_hit = 0; /* Total number of I/O Errors */
000025 int sqlite3_io_error_hardhit = 0; /* Number of non-benign errors */
000026 int sqlite3_io_error_pending = 0; /* Count down to first I/O error */
000027 int sqlite3_io_error_persist = 0; /* True if I/O errors persist */
000028 int sqlite3_io_error_benign = 0; /* True if errors are benign */
000029 int sqlite3_diskfull_pending = 0;
000030 int sqlite3_diskfull = 0;
000031 #endif /* defined(SQLITE_TEST) */
000032
000033 /*
000034 ** When testing, also keep a count of the number of open files.
000035 */
000036 #if defined(SQLITE_TEST)
000037 int sqlite3_open_file_count = 0;
000038 #endif /* defined(SQLITE_TEST) */
000039
000040 /*
000041 ** The default SQLite sqlite3_vfs implementations do not allocate
000042 ** memory (actually, os_unix.c allocates a small amount of memory
000043 ** from within OsOpen()), but some third-party implementations may.
000044 ** So we test the effects of a malloc() failing and the sqlite3OsXXX()
000045 ** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro.
000046 **
000047 ** The following functions are instrumented for malloc() failure
000048 ** testing:
000049 **
000050 ** sqlite3OsRead()
000051 ** sqlite3OsWrite()
000052 ** sqlite3OsSync()
000053 ** sqlite3OsFileSize()
000054 ** sqlite3OsLock()
000055 ** sqlite3OsCheckReservedLock()
000056 ** sqlite3OsFileControl()
000057 ** sqlite3OsShmMap()
000058 ** sqlite3OsOpen()
000059 ** sqlite3OsDelete()
000060 ** sqlite3OsAccess()
000061 ** sqlite3OsFullPathname()
000062 **
000063 */
000064 #if defined(SQLITE_TEST)
000065 int sqlite3_memdebug_vfs_oom_test = 1;
000066 #define DO_OS_MALLOC_TEST(x) \
000067 if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3JournalIsInMemory(x))) { \
000068 void *pTstAlloc = sqlite3Malloc(10); \
000069 if (!pTstAlloc) return SQLITE_IOERR_NOMEM_BKPT; \
000070 sqlite3_free(pTstAlloc); \
000071 }
000072 #else
000073 #define DO_OS_MALLOC_TEST(x)
000074 #endif
000075
000076 /*
000077 ** The following routines are convenience wrappers around methods
000078 ** of the sqlite3_file object. This is mostly just syntactic sugar. All
000079 ** of this would be completely automatic if SQLite were coded using
000080 ** C++ instead of plain old C.
000081 */
000082 void sqlite3OsClose(sqlite3_file *pId){
000083 if( pId->pMethods ){
000084 pId->pMethods->xClose(pId);
000085 pId->pMethods = 0;
000086 }
000087 }
000088 int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){
000089 DO_OS_MALLOC_TEST(id);
000090 return id->pMethods->xRead(id, pBuf, amt, offset);
000091 }
000092 int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){
000093 DO_OS_MALLOC_TEST(id);
000094 return id->pMethods->xWrite(id, pBuf, amt, offset);
000095 }
000096 int sqlite3OsTruncate(sqlite3_file *id, i64 size){
000097 return id->pMethods->xTruncate(id, size);
000098 }
000099 int sqlite3OsSync(sqlite3_file *id, int flags){
000100 DO_OS_MALLOC_TEST(id);
000101 return flags ? id->pMethods->xSync(id, flags) : SQLITE_OK;
000102 }
000103 int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){
000104 DO_OS_MALLOC_TEST(id);
000105 return id->pMethods->xFileSize(id, pSize);
000106 }
000107 int sqlite3OsLock(sqlite3_file *id, int lockType){
000108 DO_OS_MALLOC_TEST(id);
000109 return id->pMethods->xLock(id, lockType);
000110 }
000111 int sqlite3OsUnlock(sqlite3_file *id, int lockType){
000112 return id->pMethods->xUnlock(id, lockType);
000113 }
000114 int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){
000115 DO_OS_MALLOC_TEST(id);
000116 return id->pMethods->xCheckReservedLock(id, pResOut);
000117 }
000118
000119 /*
000120 ** Use sqlite3OsFileControl() when we are doing something that might fail
000121 ** and we need to know about the failures. Use sqlite3OsFileControlHint()
000122 ** when simply tossing information over the wall to the VFS and we do not
000123 ** really care if the VFS receives and understands the information since it
000124 ** is only a hint and can be safely ignored. The sqlite3OsFileControlHint()
000125 ** routine has no return value since the return value would be meaningless.
000126 */
000127 int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){
000128 if( id->pMethods==0 ) return SQLITE_NOTFOUND;
000129 #ifdef SQLITE_TEST
000130 if( op!=SQLITE_FCNTL_COMMIT_PHASETWO
000131 && op!=SQLITE_FCNTL_LOCK_TIMEOUT
000132 ){
000133 /* Faults are not injected into COMMIT_PHASETWO because, assuming SQLite
000134 ** is using a regular VFS, it is called after the corresponding
000135 ** transaction has been committed. Injecting a fault at this point
000136 ** confuses the test scripts - the COMMIT comand returns SQLITE_NOMEM
000137 ** but the transaction is committed anyway.
000138 **
000139 ** The core must call OsFileControl() though, not OsFileControlHint(),
000140 ** as if a custom VFS (e.g. zipvfs) returns an error here, it probably
000141 ** means the commit really has failed and an error should be returned
000142 ** to the user. */
000143 DO_OS_MALLOC_TEST(id);
000144 }
000145 #endif
000146 return id->pMethods->xFileControl(id, op, pArg);
000147 }
000148 void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
000149 if( id->pMethods ) (void)id->pMethods->xFileControl(id, op, pArg);
000150 }
000151
000152 int sqlite3OsSectorSize(sqlite3_file *id){
000153 int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
000154 return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
000155 }
000156 int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
000157 return id->pMethods->xDeviceCharacteristics(id);
000158 }
000159 #ifndef SQLITE_OMIT_WAL
000160 int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){
000161 return id->pMethods->xShmLock(id, offset, n, flags);
000162 }
000163 void sqlite3OsShmBarrier(sqlite3_file *id){
000164 id->pMethods->xShmBarrier(id);
000165 }
000166 int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){
000167 return id->pMethods->xShmUnmap(id, deleteFlag);
000168 }
000169 int sqlite3OsShmMap(
000170 sqlite3_file *id, /* Database file handle */
000171 int iPage,
000172 int pgsz,
000173 int bExtend, /* True to extend file if necessary */
000174 void volatile **pp /* OUT: Pointer to mapping */
000175 ){
000176 DO_OS_MALLOC_TEST(id);
000177 return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
000178 }
000179 #endif /* SQLITE_OMIT_WAL */
000180
000181 #if SQLITE_MAX_MMAP_SIZE>0
000182 /* The real implementation of xFetch and xUnfetch */
000183 int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
000184 DO_OS_MALLOC_TEST(id);
000185 return id->pMethods->xFetch(id, iOff, iAmt, pp);
000186 }
000187 int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
000188 return id->pMethods->xUnfetch(id, iOff, p);
000189 }
000190 #else
000191 /* No-op stubs to use when memory-mapped I/O is disabled */
000192 int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
000193 *pp = 0;
000194 return SQLITE_OK;
000195 }
000196 int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
000197 return SQLITE_OK;
000198 }
000199 #endif
000200
000201 /*
000202 ** The next group of routines are convenience wrappers around the
000203 ** VFS methods.
000204 */
000205 int sqlite3OsOpen(
000206 sqlite3_vfs *pVfs,
000207 const char *zPath,
000208 sqlite3_file *pFile,
000209 int flags,
000210 int *pFlagsOut
000211 ){
000212 int rc;
000213 DO_OS_MALLOC_TEST(0);
000214 /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
000215 ** down into the VFS layer. Some SQLITE_OPEN_ flags (for example,
000216 ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
000217 ** reaching the VFS. */
000218 rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x1087f7f, pFlagsOut);
000219 assert( rc==SQLITE_OK || pFile->pMethods==0 );
000220 return rc;
000221 }
000222 int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
000223 DO_OS_MALLOC_TEST(0);
000224 assert( dirSync==0 || dirSync==1 );
000225 return pVfs->xDelete(pVfs, zPath, dirSync);
000226 }
000227 int sqlite3OsAccess(
000228 sqlite3_vfs *pVfs,
000229 const char *zPath,
000230 int flags,
000231 int *pResOut
000232 ){
000233 DO_OS_MALLOC_TEST(0);
000234 return pVfs->xAccess(pVfs, zPath, flags, pResOut);
000235 }
000236 int sqlite3OsFullPathname(
000237 sqlite3_vfs *pVfs,
000238 const char *zPath,
000239 int nPathOut,
000240 char *zPathOut
000241 ){
000242 DO_OS_MALLOC_TEST(0);
000243 zPathOut[0] = 0;
000244 return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
000245 }
000246 #ifndef SQLITE_OMIT_LOAD_EXTENSION
000247 void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
000248 return pVfs->xDlOpen(pVfs, zPath);
000249 }
000250 void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
000251 pVfs->xDlError(pVfs, nByte, zBufOut);
000252 }
000253 void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
000254 return pVfs->xDlSym(pVfs, pHdle, zSym);
000255 }
000256 void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
000257 pVfs->xDlClose(pVfs, pHandle);
000258 }
000259 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
000260 int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
000261 if( sqlite3Config.iPrngSeed ){
000262 memset(zBufOut, 0, nByte);
000263 if( ALWAYS(nByte>(signed)sizeof(unsigned)) ) nByte = sizeof(unsigned int);
000264 memcpy(zBufOut, &sqlite3Config.iPrngSeed, nByte);
000265 return SQLITE_OK;
000266 }else{
000267 return pVfs->xRandomness(pVfs, nByte, zBufOut);
000268 }
000269
000270 }
000271 int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
000272 return pVfs->xSleep(pVfs, nMicro);
000273 }
000274 int sqlite3OsGetLastError(sqlite3_vfs *pVfs){
000275 return pVfs->xGetLastError ? pVfs->xGetLastError(pVfs, 0, 0) : 0;
000276 }
000277 int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
000278 int rc;
000279 /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64()
000280 ** method to get the current date and time if that method is available
000281 ** (if iVersion is 2 or greater and the function pointer is not NULL) and
000282 ** will fall back to xCurrentTime() if xCurrentTimeInt64() is
000283 ** unavailable.
000284 */
000285 if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
000286 rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut);
000287 }else{
000288 double r;
000289 rc = pVfs->xCurrentTime(pVfs, &r);
000290 *pTimeOut = (sqlite3_int64)(r*86400000.0);
000291 }
000292 return rc;
000293 }
000294
000295 int sqlite3OsOpenMalloc(
000296 sqlite3_vfs *pVfs,
000297 const char *zFile,
000298 sqlite3_file **ppFile,
000299 int flags,
000300 int *pOutFlags
000301 ){
000302 int rc;
000303 sqlite3_file *pFile;
000304 pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile);
000305 if( pFile ){
000306 rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
000307 if( rc!=SQLITE_OK ){
000308 sqlite3_free(pFile);
000309 }else{
000310 *ppFile = pFile;
000311 }
000312 }else{
000313 rc = SQLITE_NOMEM_BKPT;
000314 }
000315 return rc;
000316 }
000317 void sqlite3OsCloseFree(sqlite3_file *pFile){
000318 assert( pFile );
000319 sqlite3OsClose(pFile);
000320 sqlite3_free(pFile);
000321 }
000322
000323 /*
000324 ** This function is a wrapper around the OS specific implementation of
000325 ** sqlite3_os_init(). The purpose of the wrapper is to provide the
000326 ** ability to simulate a malloc failure, so that the handling of an
000327 ** error in sqlite3_os_init() by the upper layers can be tested.
000328 */
000329 int sqlite3OsInit(void){
000330 void *p = sqlite3_malloc(10);
000331 if( p==0 ) return SQLITE_NOMEM_BKPT;
000332 sqlite3_free(p);
000333 return sqlite3_os_init();
000334 }
000335
000336 /*
000337 ** The list of all registered VFS implementations.
000338 */
000339 static sqlite3_vfs * SQLITE_WSD vfsList = 0;
000340 #define vfsList GLOBAL(sqlite3_vfs *, vfsList)
000341
000342 /*
000343 ** Locate a VFS by name. If no name is given, simply return the
000344 ** first VFS on the list.
000345 */
000346 sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
000347 sqlite3_vfs *pVfs = 0;
000348 #if SQLITE_THREADSAFE
000349 sqlite3_mutex *mutex;
000350 #endif
000351 #ifndef SQLITE_OMIT_AUTOINIT
000352 int rc = sqlite3_initialize();
000353 if( rc ) return 0;
000354 #endif
000355 #if SQLITE_THREADSAFE
000356 mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
000357 #endif
000358 sqlite3_mutex_enter(mutex);
000359 for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
000360 if( zVfs==0 ) break;
000361 if( strcmp(zVfs, pVfs->zName)==0 ) break;
000362 }
000363 sqlite3_mutex_leave(mutex);
000364 return pVfs;
000365 }
000366
000367 /*
000368 ** Unlink a VFS from the linked list
000369 */
000370 static void vfsUnlink(sqlite3_vfs *pVfs){
000371 assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER)) );
000372 if( pVfs==0 ){
000373 /* No-op */
000374 }else if( vfsList==pVfs ){
000375 vfsList = pVfs->pNext;
000376 }else if( vfsList ){
000377 sqlite3_vfs *p = vfsList;
000378 while( p->pNext && p->pNext!=pVfs ){
000379 p = p->pNext;
000380 }
000381 if( p->pNext==pVfs ){
000382 p->pNext = pVfs->pNext;
000383 }
000384 }
000385 }
000386
000387 /*
000388 ** Register a VFS with the system. It is harmless to register the same
000389 ** VFS multiple times. The new VFS becomes the default if makeDflt is
000390 ** true.
000391 */
000392 int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
000393 MUTEX_LOGIC(sqlite3_mutex *mutex;)
000394 #ifndef SQLITE_OMIT_AUTOINIT
000395 int rc = sqlite3_initialize();
000396 if( rc ) return rc;
000397 #endif
000398 #ifdef SQLITE_ENABLE_API_ARMOR
000399 if( pVfs==0 ) return SQLITE_MISUSE_BKPT;
000400 #endif
000401
000402 MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
000403 sqlite3_mutex_enter(mutex);
000404 vfsUnlink(pVfs);
000405 if( makeDflt || vfsList==0 ){
000406 pVfs->pNext = vfsList;
000407 vfsList = pVfs;
000408 }else{
000409 pVfs->pNext = vfsList->pNext;
000410 vfsList->pNext = pVfs;
000411 }
000412 assert(vfsList);
000413 sqlite3_mutex_leave(mutex);
000414 return SQLITE_OK;
000415 }
000416
000417 /*
000418 ** Unregister a VFS so that it is no longer accessible.
000419 */
000420 int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
000421 MUTEX_LOGIC(sqlite3_mutex *mutex;)
000422 #ifndef SQLITE_OMIT_AUTOINIT
000423 int rc = sqlite3_initialize();
000424 if( rc ) return rc;
000425 #endif
000426 MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
000427 sqlite3_mutex_enter(mutex);
000428 vfsUnlink(pVfs);
000429 sqlite3_mutex_leave(mutex);
000430 return SQLITE_OK;
000431 }