/* ** 2001 September 16 ** ** 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 header file (together with is companion C source-code file ** "os.c") attempt to abstract the underlying operating system so that ** the SQLite library will work on both POSIX and windows systems. */ #ifndef _SQLITE_OS_H_ #define _SQLITE_OS_H_ /* ** Figure out if we are dealing with Unix, Windows, or some other ** operating system. */ #if defined(OS_OTHER) # if OS_OTHER==1 # undef OS_UNIX # define OS_UNIX 0 # undef OS_WIN # define OS_WIN 0 # undef OS_OS2 # define OS_OS2 0 # else # undef OS_OTHER # endif #endif #if !defined(OS_UNIX) && !defined(OS_OTHER) # define OS_OTHER 0 # ifndef OS_WIN # if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__) # define OS_WIN 1 # define OS_UNIX 0 # define OS_OS2 0 # elif defined(__EMX__) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__) # define OS_WIN 0 # define OS_UNIX 0 # define OS_OS2 1 # else # define OS_WIN 0 # define OS_UNIX 1 # define OS_OS2 0 # endif # else # define OS_UNIX 0 # define OS_OS2 0 # endif #else # ifndef OS_WIN # define OS_WIN 0 # endif #endif /* ** Define the maximum size of a temporary filename */ #if OS_WIN # include # define SQLITE_TEMPNAME_SIZE (MAX_PATH+50) #elif OS_OS2 # if (__GNUC__ > 3 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3) && defined(OS2_HIGH_MEMORY) # include /* has to be included before os2.h for linking to work */ # endif # define INCL_DOSDATETIME # define INCL_DOSFILEMGR # define INCL_DOSERRORS # define INCL_DOSMISC # define INCL_DOSPROCESS # define INCL_DOSMODULEMGR # include # define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP) #else # define SQLITE_TEMPNAME_SIZE 200 #endif /* If the SET_FULLSYNC macro is not defined above, then make it ** a no-op */ #ifndef SET_FULLSYNC # define SET_FULLSYNC(x,y) #endif /* ** The default size of a disk sector */ #ifndef SQLITE_DEFAULT_SECTOR_SIZE # define SQLITE_DEFAULT_SECTOR_SIZE 512 #endif /* ** Temporary files are named starting with this prefix followed by 16 random ** alphanumeric characters, and no file extension. They are stored in the ** OS's standard temporary file directory, and are deleted prior to exit. ** If sqlite is being embedded in another program, you may wish to change the ** prefix to reflect your program's name, so that if your program exits ** prematurely, old temporary files can be easily identified. This can be done ** using -DTEMP_FILE_PREFIX=myprefix_ on the compiler command line. ** ** 2006-10-31: The default prefix used to be "sqlite_". But then ** Mcafee started using SQLite in their anti-virus product and it ** started putting files with the "sqlite" name in the c:/temp folder. ** This annoyed many windows users. Those users would then do a ** Google search for "sqlite", find the telephone numbers of the ** developers and call to wake them up at night and complain. ** For this reason, the default name prefix is changed to be "sqlite" ** spelled backwards. So the temp files are still identified, but ** anybody smart enough to figure out the code is also likely smart ** enough to know that calling the developer will not help get rid ** of the file. */ #ifndef TEMP_FILE_PREFIX # define TEMP_FILE_PREFIX "etilqs_" #endif /* ** Define the interfaces for Unix, Windows, and OS/2. */ #if OS_UNIX #define sqlite3OsOpenReadWrite sqlite3UnixOpenReadWrite #define sqlite3OsOpenExclusive sqlite3UnixOpenExclusive #define sqlite3OsOpenReadOnly sqlite3UnixOpenReadOnly #define sqlite3OsDelete sqlite3UnixDelete #define sqlite3OsFileExists sqlite3UnixFileExists #define sqlite3OsFullPathname sqlite3UnixFullPathname #define sqlite3OsIsDirWritable sqlite3UnixIsDirWritable #define sqlite3OsSyncDirectory sqlite3UnixSyncDirectory #define sqlite3OsTempFileName sqlite3UnixTempFileName #define sqlite3OsRandomSeed sqlite3UnixRandomSeed #define sqlite3OsSleep sqlite3UnixSleep #define sqlite3OsCurrentTime sqlite3UnixCurrentTime #define sqlite3OsEnterMutex sqlite3UnixEnterMutex #define sqlite3OsLeaveMutex sqlite3UnixLeaveMutex #define sqlite3OsInMutex sqlite3UnixInMutex #define sqlite3OsThreadSpecificData sqlite3UnixThreadSpecificData #define sqlite3OsMalloc sqlite3GenericMalloc #define sqlite3OsRealloc sqlite3GenericRealloc #define sqlite3OsFree sqlite3GenericFree #define sqlite3OsAllocationSize sqlite3GenericAllocationSize #define sqlite3OsDlopen sqlite3UnixDlopen #define sqlite3OsDlsym sqlite3UnixDlsym #define sqlite3OsDlclose sqlite3UnixDlclose #endif #if OS_WIN #define sqlite3OsOpenReadWrite sqlite3WinOpenReadWrite #define sqlite3OsOpenExclusive sqlite3WinOpenExclusive #define sqlite3OsOpenReadOnly sqlite3WinOpenReadOnly #define sqlite3OsDelete sqlite3WinDelete #define sqlite3OsFileExists sqlite3WinFileExists #define sqlite3OsFullPathname sqlite3WinFullPathname #define sqlite3OsIsDirWritable sqlite3WinIsDirWritable #define sqlite3OsSyncDirectory sqlite3WinSyncDirectory #define sqlite3OsTempFileName sqlite3WinTempFileName #define sqlite3OsRandomSeed sqlite3WinRandomSeed #define sqlite3OsSleep sqlite3WinSleep #define sqlite3OsCurrentTime sqlite3WinCurrentTime #define sqlite3OsEnterMutex sqlite3WinEnterMutex #define sqlite3OsLeaveMutex sqlite3WinLeaveMutex #define sqlite3OsInMutex sqlite3WinInMutex #define sqlite3OsThreadSpecificData sqlite3WinThreadSpecificData #define sqlite3OsMalloc sqlite3GenericMalloc #define sqlite3OsRealloc sqlite3GenericRealloc #define sqlite3OsFree sqlite3GenericFree #define sqlite3OsAllocationSize sqlite3GenericAllocationSize #define sqlite3OsDlopen sqlite3WinDlopen #define sqlite3OsDlsym sqlite3WinDlsym #define sqlite3OsDlclose sqlite3WinDlclose #endif #if OS_OS2 #define sqlite3OsOpenReadWrite sqlite3Os2OpenReadWrite #define sqlite3OsOpenExclusive sqlite3Os2OpenExclusive #define sqlite3OsOpenReadOnly sqlite3Os2OpenReadOnly #define sqlite3OsDelete sqlite3Os2Delete #define sqlite3OsFileExists sqlite3Os2FileExists #define sqlite3OsFullPathname sqlite3Os2FullPathname #define sqlite3OsIsDirWritable sqlite3Os2IsDirWritable #define sqlite3OsSyncDirectory sqlite3Os2SyncDirectory #define sqlite3OsTempFileName sqlite3Os2TempFileName #define sqlite3OsRandomSeed sqlite3Os2RandomSeed #define sqlite3OsSleep sqlite3Os2Sleep #define sqlite3OsCurrentTime sqlite3Os2CurrentTime #define sqlite3OsEnterMutex sqlite3Os2EnterMutex #define sqlite3OsLeaveMutex sqlite3Os2LeaveMutex #define sqlite3OsInMutex sqlite3Os2InMutex #define sqlite3OsThreadSpecificData sqlite3Os2ThreadSpecificData #define sqlite3OsMalloc sqlite3GenericMalloc #define sqlite3OsRealloc sqlite3GenericRealloc #define sqlite3OsFree sqlite3GenericFree #define sqlite3OsAllocationSize sqlite3GenericAllocationSize #define sqlite3OsDlopen sqlite3Os2Dlopen #define sqlite3OsDlsym sqlite3Os2Dlsym #define sqlite3OsDlclose sqlite3Os2Dlclose #endif /* ** If using an alternative OS interface, then we must have an "os_other.h" ** header file available for that interface. Presumably the "os_other.h" ** header file contains #defines similar to those above. */ #if OS_OTHER # include "os_other.h" #endif /* ** Forward declarations */ typedef struct OsFile OsFile; typedef struct IoMethod IoMethod; /* ** An instance of the following structure contains pointers to all ** methods on an OsFile object. */ struct IoMethod { int (*xClose)(OsFile**); int (*xOpenDirectory)(OsFile*, const char*); int (*xRead)(OsFile*, void*, int amt); int (*xWrite)(OsFile*, const void*, int amt); int (*xSeek)(OsFile*, i64 offset); int (*xTruncate)(OsFile*, i64 size); int (*xSync)(OsFile*, int); void (*xSetFullSync)(OsFile *id, int setting); int (*xFileHandle)(OsFile *id); int (*xFileSize)(OsFile*, i64 *pSize); int (*xLock)(OsFile*, int); int (*xUnlock)(OsFile*, int); int (*xLockState)(OsFile *id); int (*xCheckReservedLock)(OsFile *id); int (*xSectorSize)(OsFile *id); }; /* ** The OsFile object describes an open disk file in an OS-dependent way. ** The version of OsFile defined here is a generic version. Each OS ** implementation defines its own subclass of this structure that contains ** additional information needed to handle file I/O. But the pMethod ** entry (pointing to the virtual function table) always occurs first ** so that we can always find the appropriate methods. */ struct OsFile { IoMethod const *pMethod; }; /* ** The following values may be passed as the second argument to ** sqlite3OsLock(). The various locks exhibit the following semantics: ** ** SHARED: Any number of processes may hold a SHARED lock simultaneously. ** RESERVED: A single process may hold a RESERVED lock on a file at ** any time. Other processes may hold and obtain new SHARED locks. ** PENDING: A single process may hold a PENDING lock on a file at ** any one time. Existing SHARED locks may persist, but no new ** SHARED locks may be obtained by other processes. ** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks. ** ** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a ** process that requests an EXCLUSIVE lock may actually obtain a PENDING ** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to ** sqlite3OsLock(). */ #define NO_LOCK 0 #define SHARED_LOCK 1 #define RESERVED_LOCK 2 #define PENDING_LOCK 3 #define EXCLUSIVE_LOCK 4 /* ** File Locking Notes: (Mostly about windows but also some info for Unix) ** ** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because ** those functions are not available. So we use only LockFile() and ** UnlockFile(). ** ** LockFile() prevents not just writing but also reading by other processes. ** A SHARED_LOCK is obtained by locking a single randomly-chosen ** byte out of a specific range of bytes. The lock byte is obtained at ** random so two separate readers can probably access the file at the ** same time, unless they are unlucky and choose the same lock byte. ** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range. ** There can only be one writer. A RESERVED_LOCK is obtained by locking ** a single byte of the file that is designated as the reserved lock byte. ** A PENDING_LOCK is obtained by locking a designated byte different from ** the RESERVED_LOCK byte. ** ** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available, ** which means we can use reader/writer locks. When reader/writer locks ** are used, the lock is placed on the same range of bytes that is used ** for probabilistic locking in Win95/98/ME. Hence, the locking scheme ** will support two or more Win95 readers or two or more WinNT readers. ** But a single Win95 reader will lock out all WinNT readers and a single ** WinNT reader will lock out all other Win95 readers. ** ** The following #defines specify the range of bytes used for locking. ** SHARED_SIZE is the number of bytes available in the pool from which ** a random byte is selected for a shared lock. The pool of bytes for ** shared locks begins at SHARED_FIRST. ** ** These #defines are available in sqlite_aux.h so that adaptors for ** connecting SQLite to other operating systems can use the same byte ** ranges for locking. In particular, the same locking strategy and ** byte ranges are used for Unix. This leaves open the possiblity of having ** clients on win95, winNT, and unix all talking to the same shared file ** and all locking correctly. To do so would require that samba (or whatever ** tool is being used for file sharing) implements locks correctly between ** windows and unix. I'm guessing that isn't likely to happen, but by ** using the same locking range we are at least open to the possibility. ** ** Locking in windows is manditory. For this reason, we cannot store ** actual data in the bytes used for locking. The pager never allocates ** the pages involved in locking therefore. SHARED_SIZE is selected so ** that all locks will fit on a single page even at the minimum page size. ** PENDING_BYTE defines the beginning of the locks. By default PENDING_BYTE ** is set high so that we don't have to allocate an unused page except ** for very large databases. But one should test the page skipping logic ** by setting PENDING_BYTE low and running the entire regression suite. ** ** Changing the value of PENDING_BYTE results in a subtly incompatible ** file format. Depending on how it is changed, you might not notice ** the incompatibility right away, even running a full regression test. ** The default location of PENDING_BYTE is the first byte past the ** 1GB boundary. ** */ #ifndef SQLITE_TEST #define PENDING_BYTE 0x40000000 /* First byte past the 1GB boundary */ #else extern unsigned int sqlite3_pending_byte; #define PENDING_BYTE sqlite3_pending_byte #endif #define RESERVED_BYTE (PENDING_BYTE+1) #define SHARED_FIRST (PENDING_BYTE+2) #define SHARED_SIZE 510 /* ** Prototypes for operating system interface routines. */ int sqlite3OsClose(OsFile**); int sqlite3OsOpenDirectory(OsFile*, const char*); int sqlite3OsRead(OsFile*, void*, int amt); int sqlite3OsWrite(OsFile*, const void*, int amt); int sqlite3OsSeek(OsFile*, i64 offset); int sqlite3OsTruncate(OsFile*, i64 size); int sqlite3OsSync(OsFile*, int); void sqlite3OsSetFullSync(OsFile *id, int setting); int sqlite3OsFileSize(OsFile*, i64 *pSize); int sqlite3OsLock(OsFile*, int); int sqlite3OsUnlock(OsFile*, int); int sqlite3OsCheckReservedLock(OsFile *id); int sqlite3OsOpenReadWrite(const char*, OsFile**, int*); int sqlite3OsOpenExclusive(const char*, OsFile**, int); int sqlite3OsOpenReadOnly(const char*, OsFile**); int sqlite3OsDelete(const char*); int sqlite3OsFileExists(const char*); char *sqlite3OsFullPathname(const char*); int sqlite3OsIsDirWritable(char*); int sqlite3OsSyncDirectory(const char*); int sqlite3OsSectorSize(OsFile *id); int sqlite3OsTempFileName(char*); int sqlite3OsRandomSeed(char*); int sqlite3OsSleep(int ms); int sqlite3OsCurrentTime(double*); void sqlite3OsEnterMutex(void); void sqlite3OsLeaveMutex(void); int sqlite3OsInMutex(int); ThreadData *sqlite3OsThreadSpecificData(int); void *sqlite3OsMalloc(int); void *sqlite3OsRealloc(void *, int); void sqlite3OsFree(void *); int sqlite3OsAllocationSize(void *); void *sqlite3OsDlopen(const char*); void *sqlite3OsDlsym(void*, const char*); int sqlite3OsDlclose(void*); #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) int sqlite3OsFileHandle(OsFile *id); int sqlite3OsLockState(OsFile *id); #endif /* ** If the SQLITE_ENABLE_REDEF_IO macro is defined, then the OS-layer ** interface routines are not called directly but are invoked using ** pointers to functions. This allows the implementation of various ** OS-layer interface routines to be modified at run-time. There are ** obscure but legitimate reasons for wanting to do this. But for ** most users, a direct call to the underlying interface is preferable ** so the the redefinable I/O interface is turned off by default. */ #ifdef SQLITE_ENABLE_REDEF_IO /* ** When redefinable I/O is enabled, a single global instance of the ** following structure holds pointers to the routines that SQLite ** uses to talk with the underlying operating system. Modify this ** structure (before using any SQLite API!) to accomodate perculiar ** operating system interfaces or behaviors. */ struct sqlite3OsVtbl { int (*xOpenReadWrite)(const char*, OsFile**, int*); int (*xOpenExclusive)(const char*, OsFile**, int); int (*xOpenReadOnly)(const char*, OsFile**); int (*xDelete)(const char*); int (*xFileExists)(const char*); char *(*xFullPathname)(const char*); int (*xIsDirWritable)(char*); int (*xSyncDirectory)(const char*); int (*xTempFileName)(char*); int (*xRandomSeed)(char*); int (*xSleep)(int ms); int (*xCurrentTime)(double*); void (*xEnterMutex)(void); void (*xLeaveMutex)(void); int (*xInMutex)(int); ThreadData *(*xThreadSpecificData)(int); void *(*xMalloc)(int); void *(*xRealloc)(void *, int); void (*xFree)(void *); int (*xAllocationSize)(void *); void *(*xDlopen)(const char*); void *(*xDlsym)(void*, const char*); int (*xDlclose)(void*); }; /* Macro used to comment out routines that do not exists when there is ** no disk I/O or extension loading */ #ifdef SQLITE_OMIT_DISKIO # define IF_DISKIO(X) 0 #else # define IF_DISKIO(X) X #endif #ifdef SQLITE_OMIT_LOAD_EXTENSION # define IF_DLOPEN(X) 0 #else # define IF_DLOPEN(X) X #endif #if defined(_SQLITE_OS_C_) || defined(SQLITE_AMALGAMATION) /* ** The os.c file implements the global virtual function table. ** We have to put this file here because the initializers ** (ex: sqlite3OsRandomSeed) are macros that are about to be ** redefined. */ struct sqlite3OsVtbl sqlite3Os = { IF_DISKIO( sqlite3OsOpenReadWrite ), IF_DISKIO( sqlite3OsOpenExclusive ), IF_DISKIO( sqlite3OsOpenReadOnly ), IF_DISKIO( sqlite3OsDelete ), IF_DISKIO( sqlite3OsFileExists ), IF_DISKIO( sqlite3OsFullPathname ), IF_DISKIO( sqlite3OsIsDirWritable ), IF_DISKIO( sqlite3OsSyncDirectory ), IF_DISKIO( sqlite3OsTempFileName ), sqlite3OsRandomSeed, sqlite3OsSleep, sqlite3OsCurrentTime, sqlite3OsEnterMutex, sqlite3OsLeaveMutex, sqlite3OsInMutex, sqlite3OsThreadSpecificData, sqlite3OsMalloc, sqlite3OsRealloc, sqlite3OsFree, sqlite3OsAllocationSize, IF_DLOPEN( sqlite3OsDlopen ), IF_DLOPEN( sqlite3OsDlsym ), IF_DLOPEN( sqlite3OsDlclose ), }; #else /* ** Files other than os.c just reference the global virtual function table. */ extern struct sqlite3OsVtbl sqlite3Os; #endif /* _SQLITE_OS_C_ */ /* This additional API routine is available with redefinable I/O */ struct sqlite3OsVtbl *sqlite3_os_switch(void); /* ** Redefine the OS interface to go through the virtual function table ** rather than calling routines directly. */ #undef sqlite3OsOpenReadWrite #undef sqlite3OsOpenExclusive #undef sqlite3OsOpenReadOnly #undef sqlite3OsDelete #undef sqlite3OsFileExists #undef sqlite3OsFullPathname #undef sqlite3OsIsDirWritable #undef sqlite3OsSyncDirectory #undef sqlite3OsTempFileName #undef sqlite3OsRandomSeed #undef sqlite3OsSleep #undef sqlite3OsCurrentTime #undef sqlite3OsEnterMutex #undef sqlite3OsLeaveMutex #undef sqlite3OsInMutex #undef sqlite3OsThreadSpecificData #undef sqlite3OsMalloc #undef sqlite3OsRealloc #undef sqlite3OsFree #undef sqlite3OsAllocationSize #define sqlite3OsOpenReadWrite sqlite3Os.xOpenReadWrite #define sqlite3OsOpenExclusive sqlite3Os.xOpenExclusive #define sqlite3OsOpenReadOnly sqlite3Os.xOpenReadOnly #define sqlite3OsDelete sqlite3Os.xDelete #define sqlite3OsFileExists sqlite3Os.xFileExists #define sqlite3OsFullPathname sqlite3Os.xFullPathname #define sqlite3OsIsDirWritable sqlite3Os.xIsDirWritable #define sqlite3OsSyncDirectory sqlite3Os.xSyncDirectory #define sqlite3OsTempFileName sqlite3Os.xTempFileName #define sqlite3OsRandomSeed sqlite3Os.xRandomSeed #define sqlite3OsSleep sqlite3Os.xSleep #define sqlite3OsCurrentTime sqlite3Os.xCurrentTime #define sqlite3OsEnterMutex sqlite3Os.xEnterMutex #define sqlite3OsLeaveMutex sqlite3Os.xLeaveMutex #define sqlite3OsInMutex sqlite3Os.xInMutex #define sqlite3OsThreadSpecificData sqlite3Os.xThreadSpecificData #define sqlite3OsMalloc sqlite3Os.xMalloc #define sqlite3OsRealloc sqlite3Os.xRealloc #define sqlite3OsFree sqlite3Os.xFree #define sqlite3OsAllocationSize sqlite3Os.xAllocationSize #endif /* SQLITE_ENABLE_REDEF_IO */ #endif /* _SQLITE_OS_H_ */