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 id->pMethods->xSync(id, flags);
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 #ifdef SQLITE_TEST
000129 if( op!=SQLITE_FCNTL_COMMIT_PHASETWO ){
000130 /* Faults are not injected into COMMIT_PHASETWO because, assuming SQLite
000131 ** is using a regular VFS, it is called after the corresponding
000132 ** transaction has been committed. Injecting a fault at this point
000133 ** confuses the test scripts - the COMMIT comand returns SQLITE_NOMEM
000134 ** but the transaction is committed anyway.
000135 **
000136 ** The core must call OsFileControl() though, not OsFileControlHint(),
000137 ** as if a custom VFS (e.g. zipvfs) returns an error here, it probably
000138 ** means the commit really has failed and an error should be returned
000139 ** to the user. */
000140 DO_OS_MALLOC_TEST(id);
000141 }
000142 #endif
000143 return id->pMethods->xFileControl(id, op, pArg);
000144 }
000145 void sqlite3OsFileControlHint(sqlite3_file *id, int op, void *pArg){
000146 (void)id->pMethods->xFileControl(id, op, pArg);
000147 }
000148
000149 int sqlite3OsSectorSize(sqlite3_file *id){
000150 int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize;
000151 return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE);
000152 }
000153 int sqlite3OsDeviceCharacteristics(sqlite3_file *id){
000154 return id->pMethods->xDeviceCharacteristics(id);
000155 }
000156 int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){
000157 return id->pMethods->xShmLock(id, offset, n, flags);
000158 }
000159 void sqlite3OsShmBarrier(sqlite3_file *id){
000160 id->pMethods->xShmBarrier(id);
000161 }
000162 int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){
000163 return id->pMethods->xShmUnmap(id, deleteFlag);
000164 }
000165 int sqlite3OsShmMap(
000166 sqlite3_file *id, /* Database file handle */
000167 int iPage,
000168 int pgsz,
000169 int bExtend, /* True to extend file if necessary */
000170 void volatile **pp /* OUT: Pointer to mapping */
000171 ){
000172 DO_OS_MALLOC_TEST(id);
000173 return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
000174 }
000175
000176 #if SQLITE_MAX_MMAP_SIZE>0
000177 /* The real implementation of xFetch and xUnfetch */
000178 int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
000179 DO_OS_MALLOC_TEST(id);
000180 return id->pMethods->xFetch(id, iOff, iAmt, pp);
000181 }
000182 int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
000183 return id->pMethods->xUnfetch(id, iOff, p);
000184 }
000185 #else
000186 /* No-op stubs to use when memory-mapped I/O is disabled */
000187 int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
000188 *pp = 0;
000189 return SQLITE_OK;
000190 }
000191 int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
000192 return SQLITE_OK;
000193 }
000194 #endif
000195
000196 /*
000197 ** The next group of routines are convenience wrappers around the
000198 ** VFS methods.
000199 */
000200 int sqlite3OsOpen(
000201 sqlite3_vfs *pVfs,
000202 const char *zPath,
000203 sqlite3_file *pFile,
000204 int flags,
000205 int *pFlagsOut
000206 ){
000207 int rc;
000208 DO_OS_MALLOC_TEST(0);
000209 /* 0x87f7f is a mask of SQLITE_OPEN_ flags that are valid to be passed
000210 ** down into the VFS layer. Some SQLITE_OPEN_ flags (for example,
000211 ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
000212 ** reaching the VFS. */
000213 rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x87f7f, pFlagsOut);
000214 assert( rc==SQLITE_OK || pFile->pMethods==0 );
000215 return rc;
000216 }
000217 int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
000218 DO_OS_MALLOC_TEST(0);
000219 assert( dirSync==0 || dirSync==1 );
000220 return pVfs->xDelete(pVfs, zPath, dirSync);
000221 }
000222 int sqlite3OsAccess(
000223 sqlite3_vfs *pVfs,
000224 const char *zPath,
000225 int flags,
000226 int *pResOut
000227 ){
000228 DO_OS_MALLOC_TEST(0);
000229 return pVfs->xAccess(pVfs, zPath, flags, pResOut);
000230 }
000231 int sqlite3OsFullPathname(
000232 sqlite3_vfs *pVfs,
000233 const char *zPath,
000234 int nPathOut,
000235 char *zPathOut
000236 ){
000237 DO_OS_MALLOC_TEST(0);
000238 zPathOut[0] = 0;
000239 return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut);
000240 }
000241 #ifndef SQLITE_OMIT_LOAD_EXTENSION
000242 void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
000243 return pVfs->xDlOpen(pVfs, zPath);
000244 }
000245 void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
000246 pVfs->xDlError(pVfs, nByte, zBufOut);
000247 }
000248 void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){
000249 return pVfs->xDlSym(pVfs, pHdle, zSym);
000250 }
000251 void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){
000252 pVfs->xDlClose(pVfs, pHandle);
000253 }
000254 #endif /* SQLITE_OMIT_LOAD_EXTENSION */
000255 int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
000256 return pVfs->xRandomness(pVfs, nByte, zBufOut);
000257 }
000258 int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){
000259 return pVfs->xSleep(pVfs, nMicro);
000260 }
000261 int sqlite3OsGetLastError(sqlite3_vfs *pVfs){
000262 return pVfs->xGetLastError ? pVfs->xGetLastError(pVfs, 0, 0) : 0;
000263 }
000264 int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){
000265 int rc;
000266 /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64()
000267 ** method to get the current date and time if that method is available
000268 ** (if iVersion is 2 or greater and the function pointer is not NULL) and
000269 ** will fall back to xCurrentTime() if xCurrentTimeInt64() is
000270 ** unavailable.
000271 */
000272 if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){
000273 rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut);
000274 }else{
000275 double r;
000276 rc = pVfs->xCurrentTime(pVfs, &r);
000277 *pTimeOut = (sqlite3_int64)(r*86400000.0);
000278 }
000279 return rc;
000280 }
000281
000282 int sqlite3OsOpenMalloc(
000283 sqlite3_vfs *pVfs,
000284 const char *zFile,
000285 sqlite3_file **ppFile,
000286 int flags,
000287 int *pOutFlags
000288 ){
000289 int rc;
000290 sqlite3_file *pFile;
000291 pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile);
000292 if( pFile ){
000293 rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags);
000294 if( rc!=SQLITE_OK ){
000295 sqlite3_free(pFile);
000296 }else{
000297 *ppFile = pFile;
000298 }
000299 }else{
000300 rc = SQLITE_NOMEM_BKPT;
000301 }
000302 return rc;
000303 }
000304 void sqlite3OsCloseFree(sqlite3_file *pFile){
000305 assert( pFile );
000306 sqlite3OsClose(pFile);
000307 sqlite3_free(pFile);
000308 }
000309
000310 /*
000311 ** This function is a wrapper around the OS specific implementation of
000312 ** sqlite3_os_init(). The purpose of the wrapper is to provide the
000313 ** ability to simulate a malloc failure, so that the handling of an
000314 ** error in sqlite3_os_init() by the upper layers can be tested.
000315 */
000316 int sqlite3OsInit(void){
000317 void *p = sqlite3_malloc(10);
000318 if( p==0 ) return SQLITE_NOMEM_BKPT;
000319 sqlite3_free(p);
000320 return sqlite3_os_init();
000321 }
000322
000323 /*
000324 ** The list of all registered VFS implementations.
000325 */
000326 static sqlite3_vfs * SQLITE_WSD vfsList = 0;
000327 #define vfsList GLOBAL(sqlite3_vfs *, vfsList)
000328
000329 /*
000330 ** Locate a VFS by name. If no name is given, simply return the
000331 ** first VFS on the list.
000332 */
000333 sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){
000334 sqlite3_vfs *pVfs = 0;
000335 #if SQLITE_THREADSAFE
000336 sqlite3_mutex *mutex;
000337 #endif
000338 #ifndef SQLITE_OMIT_AUTOINIT
000339 int rc = sqlite3_initialize();
000340 if( rc ) return 0;
000341 #endif
000342 #if SQLITE_THREADSAFE
000343 mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
000344 #endif
000345 sqlite3_mutex_enter(mutex);
000346 for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){
000347 if( zVfs==0 ) break;
000348 if( strcmp(zVfs, pVfs->zName)==0 ) break;
000349 }
000350 sqlite3_mutex_leave(mutex);
000351 return pVfs;
000352 }
000353
000354 /*
000355 ** Unlink a VFS from the linked list
000356 */
000357 static void vfsUnlink(sqlite3_vfs *pVfs){
000358 assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER)) );
000359 if( pVfs==0 ){
000360 /* No-op */
000361 }else if( vfsList==pVfs ){
000362 vfsList = pVfs->pNext;
000363 }else if( vfsList ){
000364 sqlite3_vfs *p = vfsList;
000365 while( p->pNext && p->pNext!=pVfs ){
000366 p = p->pNext;
000367 }
000368 if( p->pNext==pVfs ){
000369 p->pNext = pVfs->pNext;
000370 }
000371 }
000372 }
000373
000374 /*
000375 ** Register a VFS with the system. It is harmless to register the same
000376 ** VFS multiple times. The new VFS becomes the default if makeDflt is
000377 ** true.
000378 */
000379 int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){
000380 MUTEX_LOGIC(sqlite3_mutex *mutex;)
000381 #ifndef SQLITE_OMIT_AUTOINIT
000382 int rc = sqlite3_initialize();
000383 if( rc ) return rc;
000384 #endif
000385 #ifdef SQLITE_ENABLE_API_ARMOR
000386 if( pVfs==0 ) return SQLITE_MISUSE_BKPT;
000387 #endif
000388
000389 MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); )
000390 sqlite3_mutex_enter(mutex);
000391 vfsUnlink(pVfs);
000392 if( makeDflt || vfsList==0 ){
000393 pVfs->pNext = vfsList;
000394 vfsList = pVfs;
000395 }else{
000396 pVfs->pNext = vfsList->pNext;
000397 vfsList->pNext = pVfs;
000398 }
000399 assert(vfsList);
000400 sqlite3_mutex_leave(mutex);
000401 return SQLITE_OK;
000402 }
000403
000404 /*
000405 ** Unregister a VFS so that it is no longer accessible.
000406 */
000407 int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){
000408 #if SQLITE_THREADSAFE
000409 sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER);
000410 #endif
000411 sqlite3_mutex_enter(mutex);
000412 vfsUnlink(pVfs);
000413 sqlite3_mutex_leave(mutex);
000414 return SQLITE_OK;
000415 }