diff options
Diffstat (limited to 'src/os.c')
| -rw-r--r-- | src/os.c | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/src/os.c b/src/os.c new file mode 100644 index 0000000..0b13c86 --- /dev/null +++ b/src/os.c @@ -0,0 +1,331 @@ +/* +** 2005 November 29 +** +** 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 OS interface code that is common to all +** architectures. +*/ +#define _SQLITE_OS_C_ 1 +#include "sqliteInt.h" +#undef _SQLITE_OS_C_ + +/* +** The default SQLite sqlite3_vfs implementations do not allocate +** memory (actually, os_unix.c allocates a small amount of memory +** from within OsOpen()), but some third-party implementations may. +** So we test the effects of a malloc() failing and the sqlite3OsXXX() +** function returning SQLITE_IOERR_NOMEM using the DO_OS_MALLOC_TEST macro. +** +** The following functions are instrumented for malloc() failure +** testing: +** +** sqlite3OsOpen() +** sqlite3OsRead() +** sqlite3OsWrite() +** sqlite3OsSync() +** sqlite3OsLock() +** +*/ +#if defined(SQLITE_TEST) +int sqlite3_memdebug_vfs_oom_test = 1; + #define DO_OS_MALLOC_TEST(x) \ + if (sqlite3_memdebug_vfs_oom_test && (!x || !sqlite3IsMemJournal(x))) { \ + void *pTstAlloc = sqlite3Malloc(10); \ + if (!pTstAlloc) return SQLITE_IOERR_NOMEM; \ + sqlite3_free(pTstAlloc); \ + } +#else + #define DO_OS_MALLOC_TEST(x) +#endif + +/* +** The following routines are convenience wrappers around methods +** of the sqlite3_file object. This is mostly just syntactic sugar. All +** of this would be completely automatic if SQLite were coded using +** C++ instead of plain old C. +*/ +int sqlite3OsClose(sqlite3_file *pId){ + int rc = SQLITE_OK; + if( pId->pMethods ){ + rc = pId->pMethods->xClose(pId); + pId->pMethods = 0; + } + return rc; +} +int sqlite3OsRead(sqlite3_file *id, void *pBuf, int amt, i64 offset){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xRead(id, pBuf, amt, offset); +} +int sqlite3OsWrite(sqlite3_file *id, const void *pBuf, int amt, i64 offset){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xWrite(id, pBuf, amt, offset); +} +int sqlite3OsTruncate(sqlite3_file *id, i64 size){ + return id->pMethods->xTruncate(id, size); +} +int sqlite3OsSync(sqlite3_file *id, int flags){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xSync(id, flags); +} +int sqlite3OsFileSize(sqlite3_file *id, i64 *pSize){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xFileSize(id, pSize); +} +int sqlite3OsLock(sqlite3_file *id, int lockType){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xLock(id, lockType); +} +int sqlite3OsUnlock(sqlite3_file *id, int lockType){ + return id->pMethods->xUnlock(id, lockType); +} +int sqlite3OsCheckReservedLock(sqlite3_file *id, int *pResOut){ + DO_OS_MALLOC_TEST(id); + return id->pMethods->xCheckReservedLock(id, pResOut); +} +int sqlite3OsFileControl(sqlite3_file *id, int op, void *pArg){ + return id->pMethods->xFileControl(id, op, pArg); +} +int sqlite3OsSectorSize(sqlite3_file *id){ + int (*xSectorSize)(sqlite3_file*) = id->pMethods->xSectorSize; + return (xSectorSize ? xSectorSize(id) : SQLITE_DEFAULT_SECTOR_SIZE); +} +int sqlite3OsDeviceCharacteristics(sqlite3_file *id){ + return id->pMethods->xDeviceCharacteristics(id); +} +int sqlite3OsShmLock(sqlite3_file *id, int offset, int n, int flags){ + return id->pMethods->xShmLock(id, offset, n, flags); +} +void sqlite3OsShmBarrier(sqlite3_file *id){ + id->pMethods->xShmBarrier(id); +} +int sqlite3OsShmUnmap(sqlite3_file *id, int deleteFlag){ + return id->pMethods->xShmUnmap(id, deleteFlag); +} +int sqlite3OsShmMap( + sqlite3_file *id, /* Database file handle */ + int iPage, + int pgsz, + int bExtend, /* True to extend file if necessary */ + void volatile **pp /* OUT: Pointer to mapping */ +){ + return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp); +} + +/* +** The next group of routines are convenience wrappers around the +** VFS methods. +*/ +int sqlite3OsOpen( + sqlite3_vfs *pVfs, + const char *zPath, + sqlite3_file *pFile, + int flags, + int *pFlagsOut +){ + int rc; + DO_OS_MALLOC_TEST(0); + /* 0x87f3f is a mask of SQLITE_OPEN_ flags that are valid to be passed + ** down into the VFS layer. Some SQLITE_OPEN_ flags (for example, + ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before + ** reaching the VFS. */ + rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x87f7f, pFlagsOut); + assert( rc==SQLITE_OK || pFile->pMethods==0 ); + return rc; +} +int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){ + return pVfs->xDelete(pVfs, zPath, dirSync); +} +int sqlite3OsAccess( + sqlite3_vfs *pVfs, + const char *zPath, + int flags, + int *pResOut +){ + DO_OS_MALLOC_TEST(0); + return pVfs->xAccess(pVfs, zPath, flags, pResOut); +} +int sqlite3OsFullPathname( + sqlite3_vfs *pVfs, + const char *zPath, + int nPathOut, + char *zPathOut +){ + zPathOut[0] = 0; + return pVfs->xFullPathname(pVfs, zPath, nPathOut, zPathOut); +} +#ifndef SQLITE_OMIT_LOAD_EXTENSION +void *sqlite3OsDlOpen(sqlite3_vfs *pVfs, const char *zPath){ + return pVfs->xDlOpen(pVfs, zPath); +} +void sqlite3OsDlError(sqlite3_vfs *pVfs, int nByte, char *zBufOut){ + pVfs->xDlError(pVfs, nByte, zBufOut); +} +void (*sqlite3OsDlSym(sqlite3_vfs *pVfs, void *pHdle, const char *zSym))(void){ + return pVfs->xDlSym(pVfs, pHdle, zSym); +} +void sqlite3OsDlClose(sqlite3_vfs *pVfs, void *pHandle){ + pVfs->xDlClose(pVfs, pHandle); +} +#endif /* SQLITE_OMIT_LOAD_EXTENSION */ +int sqlite3OsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){ + return pVfs->xRandomness(pVfs, nByte, zBufOut); +} +int sqlite3OsSleep(sqlite3_vfs *pVfs, int nMicro){ + return pVfs->xSleep(pVfs, nMicro); +} +int sqlite3OsCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *pTimeOut){ + int rc; + /* IMPLEMENTATION-OF: R-49045-42493 SQLite will use the xCurrentTimeInt64() + ** method to get the current date and time if that method is available + ** (if iVersion is 2 or greater and the function pointer is not NULL) and + ** will fall back to xCurrentTime() if xCurrentTimeInt64() is + ** unavailable. + */ + if( pVfs->iVersion>=2 && pVfs->xCurrentTimeInt64 ){ + rc = pVfs->xCurrentTimeInt64(pVfs, pTimeOut); + }else{ + double r; + rc = pVfs->xCurrentTime(pVfs, &r); + *pTimeOut = (sqlite3_int64)(r*86400000.0); + } + return rc; +} + +int sqlite3OsOpenMalloc( + sqlite3_vfs *pVfs, + const char *zFile, + sqlite3_file **ppFile, + int flags, + int *pOutFlags +){ + int rc = SQLITE_NOMEM; + sqlite3_file *pFile; + pFile = (sqlite3_file *)sqlite3MallocZero(pVfs->szOsFile); + if( pFile ){ + rc = sqlite3OsOpen(pVfs, zFile, pFile, flags, pOutFlags); + if( rc!=SQLITE_OK ){ + sqlite3_free(pFile); + }else{ + *ppFile = pFile; + } + } + return rc; +} +int sqlite3OsCloseFree(sqlite3_file *pFile){ + int rc = SQLITE_OK; + assert( pFile ); + rc = sqlite3OsClose(pFile); + sqlite3_free(pFile); + return rc; +} + +/* +** This function is a wrapper around the OS specific implementation of +** sqlite3_os_init(). The purpose of the wrapper is to provide the +** ability to simulate a malloc failure, so that the handling of an +** error in sqlite3_os_init() by the upper layers can be tested. +*/ +int sqlite3OsInit(void){ + void *p = sqlite3_malloc(10); + if( p==0 ) return SQLITE_NOMEM; + sqlite3_free(p); + return sqlite3_os_init(); +} + +/* +** The list of all registered VFS implementations. +*/ +static sqlite3_vfs * SQLITE_WSD vfsList = 0; +#define vfsList GLOBAL(sqlite3_vfs *, vfsList) + +/* +** Locate a VFS by name. If no name is given, simply return the +** first VFS on the list. +*/ +sqlite3_vfs *sqlite3_vfs_find(const char *zVfs){ + sqlite3_vfs *pVfs = 0; +#if SQLITE_THREADSAFE + sqlite3_mutex *mutex; +#endif +#ifndef SQLITE_OMIT_AUTOINIT + int rc = sqlite3_initialize(); + if( rc ) return 0; +#endif +#if SQLITE_THREADSAFE + mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); +#endif + sqlite3_mutex_enter(mutex); + for(pVfs = vfsList; pVfs; pVfs=pVfs->pNext){ + if( zVfs==0 ) break; + if( strcmp(zVfs, pVfs->zName)==0 ) break; + } + sqlite3_mutex_leave(mutex); + return pVfs; +} + +/* +** Unlink a VFS from the linked list +*/ +static void vfsUnlink(sqlite3_vfs *pVfs){ + assert( sqlite3_mutex_held(sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER)) ); + if( pVfs==0 ){ + /* No-op */ + }else if( vfsList==pVfs ){ + vfsList = pVfs->pNext; + }else if( vfsList ){ + sqlite3_vfs *p = vfsList; + while( p->pNext && p->pNext!=pVfs ){ + p = p->pNext; + } + if( p->pNext==pVfs ){ + p->pNext = pVfs->pNext; + } + } +} + +/* +** Register a VFS with the system. It is harmless to register the same +** VFS multiple times. The new VFS becomes the default if makeDflt is +** true. +*/ +int sqlite3_vfs_register(sqlite3_vfs *pVfs, int makeDflt){ + MUTEX_LOGIC(sqlite3_mutex *mutex;) +#ifndef SQLITE_OMIT_AUTOINIT + int rc = sqlite3_initialize(); + if( rc ) return rc; +#endif + MUTEX_LOGIC( mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); ) + sqlite3_mutex_enter(mutex); + vfsUnlink(pVfs); + if( makeDflt || vfsList==0 ){ + pVfs->pNext = vfsList; + vfsList = pVfs; + }else{ + pVfs->pNext = vfsList->pNext; + vfsList->pNext = pVfs; + } + assert(vfsList); + sqlite3_mutex_leave(mutex); + return SQLITE_OK; +} + +/* +** Unregister a VFS so that it is no longer accessible. +*/ +int sqlite3_vfs_unregister(sqlite3_vfs *pVfs){ +#if SQLITE_THREADSAFE + sqlite3_mutex *mutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MASTER); +#endif + sqlite3_mutex_enter(mutex); + vfsUnlink(pVfs); + sqlite3_mutex_leave(mutex); + return SQLITE_OK; +} |