/* ** 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 file contains code that is specific to particular operating ** systems. The purpose of this file is to provide a uniform abstraction ** on which the rest of SQLite can operate. */ #include "os.h" /* Must be first to enable large file support */ #include "sqliteInt.h" #if OS_UNIX # include # include # include # ifndef O_LARGEFILE # define O_LARGEFILE 0 # endif # ifdef SQLITE_DISABLE_LFS # undef O_LARGEFILE # define O_LARGEFILE 0 # endif # ifndef O_NOFOLLOW # define O_NOFOLLOW 0 # endif # ifndef O_BINARY # define O_BINARY 0 # endif #endif #if OS_WIN # include #endif #if OS_MAC # include # include # include # include # include # include # include #endif /* ** The DJGPP compiler environment looks mostly like Unix, but it ** lacks the fcntl() system call. So redefine fcntl() to be something ** that always succeeds. This means that locking does not occur under ** DJGPP. But its DOS - what did you expect? */ #ifdef __DJGPP__ # define fcntl(A,B,C) 0 #endif /* ** Macros for performance tracing. Normally turned off */ #if 0 static int last_page = 0; __inline__ unsigned long long int hwtime(void){ unsigned long long int x; __asm__("rdtsc\n\t" "mov %%edx, %%ecx\n\t" :"=A" (x)); return x; } static unsigned long long int g_start; static unsigned int elapse; #define TIMER_START g_start=hwtime() #define TIMER_END elapse=hwtime()-g_start #define SEEK(X) last_page=(X) #define TRACE1(X) fprintf(stderr,X) #define TRACE2(X,Y) fprintf(stderr,X,Y) #define TRACE3(X,Y,Z) fprintf(stderr,X,Y,Z) #define TRACE4(X,Y,Z,A) fprintf(stderr,X,Y,Z,A) #define TRACE5(X,Y,Z,A,B) fprintf(stderr,X,Y,Z,A,B) #else #define TIMER_START #define TIMER_END #define SEEK(X) #define TRACE1(X) #define TRACE2(X,Y) #define TRACE3(X,Y,Z) #define TRACE4(X,Y,Z,A) #define TRACE5(X,Y,Z,A,B) #endif #if OS_UNIX /* ** Here is the dirt on POSIX advisory locks: ANSI STD 1003.1 (1996) ** section 6.5.2.2 lines 483 through 490 specify that when a process ** sets or clears a lock, that operation overrides any prior locks set ** by the same process. It does not explicitly say so, but this implies ** that it overrides locks set by the same process using a different ** file descriptor. Consider this test case: ** ** int fd1 = open("./file1", O_RDWR|O_CREAT, 0644); ** int fd2 = open("./file2", O_RDWR|O_CREAT, 0644); ** ** Suppose ./file1 and ./file2 are really the same file (because ** one is a hard or symbolic link to the other) then if you set ** an exclusive lock on fd1, then try to get an exclusive lock ** on fd2, it works. I would have expected the second lock to ** fail since there was already a lock on the file due to fd1. ** But not so. Since both locks came from the same process, the ** second overrides the first, even though they were on different ** file descriptors opened on different file names. ** ** Bummer. If you ask me, this is broken. Badly broken. It means ** that we cannot use POSIX locks to synchronize file access among ** competing threads of the same process. POSIX locks will work fine ** to synchronize access for threads in separate processes, but not ** threads within the same process. ** ** To work around the problem, SQLite has to manage file locks internally ** on its own. Whenever a new database is opened, we have to find the ** specific inode of the database file (the inode is determined by the ** st_dev and st_ino fields of the stat structure that fstat() fills in) ** and check for locks already existing on that inode. When locks are ** created or removed, we have to look at our own internal record of the ** locks to see if another thread has previously set a lock on that same ** inode. ** ** The OsFile structure for POSIX is no longer just an integer file ** descriptor. It is now a structure that holds the integer file ** descriptor and a pointer to a structure that describes the internal ** locks on the corresponding inode. There is one locking structure ** per inode, so if the same inode is opened twice, both OsFile structures ** point to the same locking structure. The locking structure keeps ** a reference count (so we will know when to delete it) and a "cnt" ** field that tells us its internal lock status. cnt==0 means the ** file is unlocked. cnt==-1 means the file has an exclusive lock. ** cnt>0 means there are cnt shared locks on the file. ** ** Any attempt to lock or unlock a file first checks the locking ** structure. The fcntl() system call is only invoked to set a ** POSIX lock if the internal lock structure transitions between ** a locked and an unlocked state. */ /* ** An instance of the following structure serves as the key used ** to locate a particular lockInfo structure given its inode. */ struct inodeKey { dev_t dev; /* Device number */ ino_t ino; /* Inode number */ }; /* ** An instance of the following structure is allocated for each inode. ** A single inode can have multiple file descriptors, so each OsFile ** structure contains a pointer to an instance of this object and this ** object keeps a count of the number of OsFiles pointing to it. */ struct lockInfo { struct inodeKey key; /* The lookup key */ int cnt; /* 0: unlocked. -1: write lock. 1...: read lock. */ int nRef; /* Number of pointers to this structure */ }; /* ** This hash table maps inodes (in the form of inodeKey structures) into ** pointers to lockInfo structures. */ static Hash lockHash = { SQLITE_HASH_BINARY, 0, 0, 0, 0, 0 }; /* ** Given a file descriptor, locate a lockInfo structure that describes ** that file descriptor. Create a new one if necessary. NULL might ** be returned if malloc() fails. */ static struct lockInfo *findLockInfo(int fd){ int rc; struct inodeKey key; struct stat statbuf; struct lockInfo *pInfo; rc = fstat(fd, &statbuf); if( rc!=0 ) return 0; memset(&key, 0, sizeof(key)); key.dev = statbuf.st_dev; key.ino = statbuf.st_ino; pInfo = (struct lockInfo*)sqliteHashFind(&lockHash, &key, sizeof(key)); if( pInfo==0 ){ struct lockInfo *pOld; pInfo = sqliteMalloc( sizeof(*pInfo) ); if( pInfo==0 ) return 0; pInfo->key = key; pInfo->nRef = 1; pInfo->cnt = 0; pOld = sqliteHashInsert(&lockHash, &pInfo->key, sizeof(key), pInfo); if( pOld!=0 ){ assert( pOld==pInfo ); sqliteFree(pInfo); pInfo = 0; } }else{ pInfo->nRef++; } return pInfo; } /* ** Release a lockInfo structure previously allocated by findLockInfo(). */ static void releaseLockInfo(struct lockInfo *pInfo){ pInfo->nRef--; if( pInfo->nRef==0 ){ sqliteHashInsert(&lockHash, &pInfo->key, sizeof(pInfo->key), 0); sqliteFree(pInfo); } } #endif /** POSIX advisory lock work-around **/ /* ** If we compile with the SQLITE_TEST macro set, then the following block ** of code will give us the ability to simulate a disk I/O error. This ** is used for testing the I/O recovery logic. */ #ifdef SQLITE_TEST int sqlite_io_error_pending = 0; #define SimulateIOError(A) \ if( sqlite_io_error_pending ) \ if( sqlite_io_error_pending-- == 1 ){ local_ioerr(); return A; } static void local_ioerr(){ sqlite_io_error_pending = 0; /* Really just a place to set a breakpoint */ } #else #define SimulateIOError(A) #endif /* ** When testing, keep a count of the number of open files. */ #ifdef SQLITE_TEST int sqlite_open_file_count = 0; #define OpenCounter(X) sqlite_open_file_count+=(X) #else #define OpenCounter(X) #endif /* ** Delete the named file */ int sqliteOsDelete(const char *zFilename){ #if OS_UNIX unlink(zFilename); #endif #if OS_WIN DeleteFile(zFilename); #endif #if OS_MAC unlink(zFilename); #endif return SQLITE_OK; } /* ** Return TRUE if the named file exists. */ int sqliteOsFileExists(const char *zFilename){ #if OS_UNIX return access(zFilename, 0)==0; #endif #if OS_WIN return GetFileAttributes(zFilename) != 0xffffffff; #endif #if OS_MAC return access(zFilename, 0)==0; #endif } #if 0 /* NOT USED */ /* ** Change the name of an existing file. */ int sqliteOsFileRename(const char *zOldName, const char *zNewName){ #if OS_UNIX if( link(zOldName, zNewName) ){ return SQLITE_ERROR; } unlink(zOldName); return SQLITE_OK; #endif #if OS_WIN if( !MoveFile(zOldName, zNewName) ){ return SQLITE_ERROR; } return SQLITE_OK; #endif #if OS_MAC /**** FIX ME ***/ return SQLITE_ERROR; #endif } #endif /* NOT USED */ /* ** Attempt to open a file for both reading and writing. If that ** fails, try opening it read-only. If the file does not exist, ** try to create it. ** ** On success, a handle for the open file is written to *id ** and *pReadonly is set to 0 if the file was opened for reading and ** writing or 1 if the file was opened read-only. The function returns ** SQLITE_OK. ** ** On failure, the function returns SQLITE_CANTOPEN and leaves ** *id and *pReadonly unchanged. */ int sqliteOsOpenReadWrite( const char *zFilename, OsFile *id, int *pReadonly ){ #if OS_UNIX id->dirfd = -1; id->fd = open(zFilename, O_RDWR|O_CREAT|O_LARGEFILE|O_BINARY, 0644); if( id->fd<0 ){ id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY); if( id->fd<0 ){ return SQLITE_CANTOPEN; } *pReadonly = 1; }else{ *pReadonly = 0; } sqliteOsEnterMutex(); id->pLock = findLockInfo(id->fd); sqliteOsLeaveMutex(); if( id->pLock==0 ){ close(id->fd); return SQLITE_NOMEM; } id->locked = 0; TRACE3("OPEN %-3d %s\n", id->fd, zFilename); OpenCounter(+1); return SQLITE_OK; #endif #if OS_WIN HANDLE h = CreateFile(zFilename, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS, NULL ); if( h==INVALID_HANDLE_VALUE ){ h = CreateFile(zFilename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS, NULL ); if( h==INVALID_HANDLE_VALUE ){ return SQLITE_CANTOPEN; } *pReadonly = 1; }else{ *pReadonly = 0; } id->h = h; id->locked = 0; OpenCounter(+1); return SQLITE_OK; #endif #if OS_MAC FSSpec fsSpec; # ifdef _LARGE_FILE HFSUniStr255 dfName; FSRef fsRef; if( __path2fss(zFilename, &fsSpec) != noErr ){ if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr ) return SQLITE_CANTOPEN; } if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr ) return SQLITE_CANTOPEN; FSGetDataForkName(&dfName); if( FSOpenFork(&fsRef, dfName.length, dfName.unicode, fsRdWrShPerm, &(id->refNum)) != noErr ){ if( FSOpenFork(&fsRef, dfName.length, dfName.unicode, fsRdWrPerm, &(id->refNum)) != noErr ){ if (FSOpenFork(&fsRef, dfName.length, dfName.unicode, fsRdPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; else *pReadonly = 1; } else *pReadonly = 0; } else *pReadonly = 0; # else __path2fss(zFilename, &fsSpec); if( !sqliteOsFileExists(zFilename) ){ if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr ) return SQLITE_CANTOPEN; } if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNum)) != noErr ){ if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrPerm, &(id->refNum)) != noErr ){ if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; else *pReadonly = 1; } else *pReadonly = 0; } else *pReadonly = 0; # endif if( HOpenRF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNumRF)) != noErr){ id->refNumRF = -1; } id->locked = 0; id->delOnClose = 0; OpenCounter(+1); return SQLITE_OK; #endif } /* ** Attempt to open a new file for exclusive access by this process. ** The file will be opened for both reading and writing. To avoid ** a potential security problem, we do not allow the file to have ** previously existed. Nor do we allow the file to be a symbolic ** link. ** ** If delFlag is true, then make arrangements to automatically delete ** the file when it is closed. ** ** On success, write the file handle into *id and return SQLITE_OK. ** ** On failure, return SQLITE_CANTOPEN. */ int sqliteOsOpenExclusive(const char *zFilename, OsFile *id, int delFlag){ #if OS_UNIX if( access(zFilename, 0)==0 ){ return SQLITE_CANTOPEN; } id->dirfd = -1; id->fd = open(zFilename, O_RDWR|O_CREAT|O_EXCL|O_NOFOLLOW|O_LARGEFILE|O_BINARY, 0600); if( id->fd<0 ){ return SQLITE_CANTOPEN; } sqliteOsEnterMutex(); id->pLock = findLockInfo(id->fd); sqliteOsLeaveMutex(); if( id->pLock==0 ){ close(id->fd); unlink(zFilename); return SQLITE_NOMEM; } id->locked = 0; if( delFlag ){ unlink(zFilename); } TRACE3("OPEN-EX %-3d %s\n", id->fd, zFilename); OpenCounter(+1); return SQLITE_OK; #endif #if OS_WIN HANDLE h; int fileflags; if( delFlag ){ fileflags = FILE_ATTRIBUTE_TEMPORARY | FILE_FLAG_RANDOM_ACCESS | FILE_FLAG_DELETE_ON_CLOSE; }else{ fileflags = FILE_FLAG_RANDOM_ACCESS; } h = CreateFile(zFilename, GENERIC_READ | GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, fileflags, NULL ); if( h==INVALID_HANDLE_VALUE ){ return SQLITE_CANTOPEN; } id->h = h; id->locked = 0; OpenCounter(+1); return SQLITE_OK; #endif #if OS_MAC FSSpec fsSpec; # ifdef _LARGE_FILE HFSUniStr255 dfName; FSRef fsRef; __path2fss(zFilename, &fsSpec); if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr ) return SQLITE_CANTOPEN; if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr ) return SQLITE_CANTOPEN; FSGetDataForkName(&dfName); if( FSOpenFork(&fsRef, dfName.length, dfName.unicode, fsRdWrPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; # else __path2fss(zFilename, &fsSpec); if( HCreate(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, 'SQLI', cDocumentFile) != noErr ) return SQLITE_CANTOPEN; if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; # endif id->refNumRF = -1; id->locked = 0; id->delOnClose = delFlag; if (delFlag) id->pathToDel = sqliteOsFullPathname(zFilename); OpenCounter(+1); return SQLITE_OK; #endif } /* ** Attempt to open a new file for read-only access. ** ** On success, write the file handle into *id and return SQLITE_OK. ** ** On failure, return SQLITE_CANTOPEN. */ int sqliteOsOpenReadOnly(const char *zFilename, OsFile *id){ #if OS_UNIX id->dirfd = -1; id->fd = open(zFilename, O_RDONLY|O_LARGEFILE|O_BINARY); if( id->fd<0 ){ return SQLITE_CANTOPEN; } sqliteOsEnterMutex(); id->pLock = findLockInfo(id->fd); sqliteOsLeaveMutex(); if( id->pLock==0 ){ close(id->fd); return SQLITE_NOMEM; } id->locked = 0; TRACE3("OPEN-RO %-3d %s\n", id->fd, zFilename); OpenCounter(+1); return SQLITE_OK; #endif #if OS_WIN HANDLE h = CreateFile(zFilename, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_RANDOM_ACCESS, NULL ); if( h==INVALID_HANDLE_VALUE ){ return SQLITE_CANTOPEN; } id->h = h; id->locked = 0; OpenCounter(+1); return SQLITE_OK; #endif #if OS_MAC FSSpec fsSpec; # ifdef _LARGE_FILE HFSUniStr255 dfName; FSRef fsRef; if( __path2fss(zFilename, &fsSpec) != noErr ) return SQLITE_CANTOPEN; if( FSpMakeFSRef(&fsSpec, &fsRef) != noErr ) return SQLITE_CANTOPEN; FSGetDataForkName(&dfName); if( FSOpenFork(&fsRef, dfName.length, dfName.unicode, fsRdPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; # else __path2fss(zFilename, &fsSpec); if( HOpenDF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdPerm, &(id->refNum)) != noErr ) return SQLITE_CANTOPEN; # endif if( HOpenRF(fsSpec.vRefNum, fsSpec.parID, fsSpec.name, fsRdWrShPerm, &(id->refNumRF)) != noErr){ id->refNumRF = -1; } id->locked = 0; id->delOnClose = 0; OpenCounter(+1); return SQLITE_OK; #endif } /* ** Attempt to open a file descriptor for the directory that contains a ** file. This file descriptor can be used to fsync() the directory ** in order to make sure the creation of a new file is actually written ** to disk. ** ** This routine is only meaningful for Unix. It is a no-op under ** windows since windows does not support hard links. ** ** On success, a handle for a previously open file is at *id is ** updated with the new directory file descriptor and SQLITE_OK is ** returned. ** ** On failure, the function returns SQLITE_CANTOPEN and leaves ** *id unchanged. */ int sqliteOsOpenDirectory( const char *zDirname, OsFile *id ){ #if OS_UNIX if( id->fd<0 ){ /* Do not open the directory if the corresponding file is not already ** open. */ return SQLITE_CANTOPEN; } assert( id->dirfd<0 ); id->dirfd = open(zDirname, O_RDONLY|O_BINARY, 0644); if( id->dirfd<0 ){ return SQLITE_CANTOPEN; } TRACE3("OPENDIR %-3d %s\n", id->dirfd, zDirname); #endif return SQLITE_OK; } /* ** Create a temporary file name in zBuf. zBuf must be big enough to ** hold at least SQLITE_TEMPNAME_SIZE characters. */ int sqliteOsTempFileName(char *zBuf){ #if OS_UNIX static const char *azDirs[] = { "/var/tmp", "/usr/tmp", "/tmp", ".", }; static char zChars[] = "abcdefghijklmnopqrstuvwxyz" "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "0123456789"; int i, j; struct stat buf; const char *zDir = "."; for(i=0; i0 && zTempPath[i-1]=='\\'; i--){} zTempPath[i] = 0; for(;;){ sprintf(zBuf, "%s\\"TEMP_FILE_PREFIX, zTempPath); j = strlen(zBuf); for(i=0; i<15; i++){ int n = sqliteRandomByte() % (sizeof(zChars) - 1); zBuf[j++] = zChars[n]; } zBuf[j] = 0; if( !sqliteOsFileExists(zBuf) ) break; } #endif #if OS_MAC static char zChars[] = "abcdefghijklmnopqrstuvwxyz" "ABCDEFGHIJKLMNOPQRSTUVWXYZ" "0123456789"; int i, j; char zTempPath[SQLITE_TEMPNAME_SIZE]; char zdirName[32]; CInfoPBRec infoRec; Str31 dirName; memset(&infoRec, 0, sizeof(infoRec)); memset(zTempPath, 0, SQLITE_TEMPNAME_SIZE); if( FindFolder(kOnSystemDisk, kTemporaryFolderType, kCreateFolder, &(infoRec.dirInfo.ioVRefNum), &(infoRec.dirInfo.ioDrParID)) == noErr ){ infoRec.dirInfo.ioNamePtr = dirName; do{ infoRec.dirInfo.ioFDirIndex = -1; infoRec.dirInfo.ioDrDirID = infoRec.dirInfo.ioDrParID; if( PBGetCatInfoSync(&infoRec) == noErr ){ CopyPascalStringToC(dirName, zdirName); i = strlen(zdirName); memmove(&(zTempPath[i+1]), zTempPath, strlen(zTempPath)); strcpy(zTempPath, zdirName); zTempPath[i] = ':'; }else{ *zTempPath = 0; break; } } while( infoRec.dirInfo.ioDrDirID != fsRtDirID ); } if( *zTempPath == 0 ) getcwd(zTempPath, SQLITE_TEMPNAME_SIZE-24); for(;;){ sprintf(zBuf, "%s"TEMP_FILE_PREFIX, zTempPath); j = strlen(zBuf); for(i=0; i<15; i++){ int n = sqliteRandomByte() % sizeof(zChars); zBuf[j++] = zChars[n]; } zBuf[j] = 0; if( !sqliteOsFileExists(zBuf) ) break; } #endif return SQLITE_OK; } /* ** Close a file */ int sqliteOsClose(OsFile *id){ #if OS_UNIX close(id->fd); if( id->dirfd>=0 ) close(id->dirfd); id->dirfd = -1; sqliteOsEnterMutex(); releaseLockInfo(id->pLock); sqliteOsLeaveMutex(); TRACE2("CLOSE %-3d\n", id->fd); OpenCounter(-1); return SQLITE_OK; #endif #if OS_WIN CloseHandle(id->h); OpenCounter(-1); return SQLITE_OK; #endif #if OS_MAC if( id->refNumRF!=-1 ) FSClose(id->refNumRF); # ifdef _LARGE_FILE FSCloseFork(id->refNum); # else FSClose(id->refNum); # endif if( id->delOnClose ){ unlink(id->pathToDel); sqliteFree(id->pathToDel); } OpenCounter(-1); return SQLITE_OK; #endif } /* ** Read data from a file into a buffer. Return SQLITE_OK if all ** bytes were read successfully and SQLITE_IOERR if anything goes ** wrong. */ int sqliteOsRead(OsFile *id, void *pBuf, int amt){ #if OS_UNIX int got; SimulateIOError(SQLITE_IOERR); TIMER_START; got = read(id->fd, pBuf, amt); TIMER_END; TRACE4("READ %-3d %7d %d\n", id->fd, last_page, elapse); SEEK(0); /* if( got<0 ) got = 0; */ if( got==amt ){ return SQLITE_OK; }else{ return SQLITE_IOERR; } #endif #if OS_WIN DWORD got; SimulateIOError(SQLITE_IOERR); TRACE2("READ %d\n", last_page); if( !ReadFile(id->h, pBuf, amt, &got, 0) ){ got = 0; } if( got==(DWORD)amt ){ return SQLITE_OK; }else{ return SQLITE_IOERR; } #endif #if OS_MAC int got; SimulateIOError(SQLITE_IOERR); TRACE2("READ %d\n", last_page); # ifdef _LARGE_FILE FSReadFork(id->refNum, fsAtMark, 0, (ByteCount)amt, pBuf, (ByteCount*)&got); # else got = amt; FSRead(id->refNum, &got, pBuf); # endif if( got==amt ){ return SQLITE_OK; }else{ return SQLITE_IOERR; } #endif } /* ** Write data from a buffer into a file. Return SQLITE_OK on success ** or some other error code on failure. */ int sqliteOsWrite(OsFile *id, const void *pBuf, int amt){ #if OS_UNIX int wrote = 0; SimulateIOError(SQLITE_IOERR); TIMER_START; while( amt>0 && (wrote = write(id->fd, pBuf, amt))>0 ){ amt -= wrote; pBuf = &((char*)pBuf)[wrote]; } TIMER_END; TRACE4("WRITE %-3d %7d %d\n", id->fd, last_page, elapse); SEEK(0); if( amt>0 ){ return SQLITE_FULL; } return SQLITE_OK; #endif #if OS_WIN int rc; DWORD wrote; SimulateIOError(SQLITE_IOERR); TRACE2("WRITE %d\n", last_page); while( amt>0 && (rc = WriteFile(id->h, pBuf, amt, &wrote, 0))!=0 && wrote>0 ){ amt -= wrote; pBuf = &((char*)pBuf)[wrote]; } if( !rc || amt>(int)wrote ){ return SQLITE_FULL; } return SQLITE_OK; #endif #if OS_MAC OSErr oserr; int wrote = 0; SimulateIOError(SQLITE_IOERR); TRACE2("WRITE %d\n", last_page); while( amt>0 ){ # ifdef _LARGE_FILE oserr = FSWriteFork(id->refNum, fsAtMark, 0, (ByteCount)amt, pBuf, (ByteCount*)&wrote); # else wrote = amt; oserr = FSWrite(id->refNum, &wrote, pBuf); # endif if( wrote == 0 || oserr != noErr) break; amt -= wrote; pBuf = &((char*)pBuf)[wrote]; } if( oserr != noErr || amt>wrote ){ return SQLITE_FULL; } return SQLITE_OK; #endif } /* ** Move the read/write pointer in a file. */ int sqliteOsSeek(OsFile *id, off_t offset){ SEEK(offset/1024 + 1); #if OS_UNIX lseek(id->fd, offset, SEEK_SET); return SQLITE_OK; #endif #if OS_WIN { LONG upperBits = offset>>32; LONG lowerBits = offset & 0xffffffff; DWORD rc; rc = SetFilePointer(id->h, lowerBits, &upperBits, FILE_BEGIN); /* TRACE3("SEEK rc=0x%x upper=0x%x\n", rc, upperBits); */ } return SQLITE_OK; #endif #if OS_MAC { off_t curSize; if( sqliteOsFileSize(id, &curSize) != SQLITE_OK ){ return SQLITE_IOERR; } if( offset >= curSize ){ if( sqliteOsTruncate(id, offset+1) != SQLITE_OK ){ return SQLITE_IOERR; } } # ifdef _LARGE_FILE if( FSSetForkPosition(id->refNum, fsFromStart, offset) != noErr ){ # else if( SetFPos(id->refNum, fsFromStart, offset) != noErr ){ # endif return SQLITE_IOERR; }else{ return SQLITE_OK; } } #endif } /* ** Make sure all writes to a particular file are committed to disk. ** ** Under Unix, also make sure that the directory entry for the file ** has been created by fsync-ing the directory that contains the file. ** If we do not do this and we encounter a power failure, the directory ** entry for the journal might not exist after we reboot. The next ** SQLite to access the file will not know that the journal exists (because ** the directory entry for the journal was never created) and the transaction ** will not roll back - possibly leading to database corruption. */ int sqliteOsSync(OsFile *id){ #if OS_UNIX SimulateIOError(SQLITE_IOERR); TRACE2("SYNC %-3d\n", id->fd); if( fsync(id->fd) ){ return SQLITE_IOERR; }else{ if( id->dirfd>=0 ){ TRACE2("DIRSYNC %-3d\n", id->dirfd); fsync(id->dirfd); close(id->dirfd); /* Only need to sync once, so close the directory */ id->dirfd = -1; /* when we are done. */ } return SQLITE_OK; } #endif #if OS_WIN if( FlushFileBuffers(id->h) ){ return SQLITE_OK; }else{ return SQLITE_IOERR; } #endif #if OS_MAC # ifdef _LARGE_FILE if( FSFlushFork(id->refNum) != noErr ){ # else ParamBlockRec params; memset(¶ms, 0, sizeof(ParamBlockRec)); params.ioParam.ioRefNum = id->refNum; if( PBFlushFileSync(¶ms) != noErr ){ # endif return SQLITE_IOERR; }else{ return SQLITE_OK; } #endif } /* ** Truncate an open file to a specified size */ int sqliteOsTruncate(OsFile *id, off_t nByte){ SimulateIOError(SQLITE_IOERR); #if OS_UNIX return ftruncate(id->fd, nByte)==0 ? SQLITE_OK : SQLITE_IOERR; #endif #if OS_WIN { LONG upperBits = nByte>>32; SetFilePointer(id->h, nByte, &upperBits, FILE_BEGIN); SetEndOfFile(id->h); } return SQLITE_OK; #endif #if OS_MAC # ifdef _LARGE_FILE if( FSSetForkSize(id->refNum, fsFromStart, nByte) != noErr){ # else if( SetEOF(id->refNum, nByte) != noErr ){ # endif return SQLITE_IOERR; }else{ return SQLITE_OK; } #endif } /* ** Determine the current size of a file in bytes */ int sqliteOsFileSize(OsFile *id, off_t *pSize){ #if OS_UNIX struct stat buf; SimulateIOError(SQLITE_IOERR); if( fstat(id->fd, &buf)!=0 ){ return SQLITE_IOERR; } *pSize = buf.st_size; return SQLITE_OK; #endif #if OS_WIN DWORD upperBits, lowerBits; SimulateIOError(SQLITE_IOERR); lowerBits = GetFileSize(id->h, &upperBits); *pSize = (((off_t)upperBits)<<32) + lowerBits; return SQLITE_OK; #endif #if OS_MAC # ifdef _LARGE_FILE if( FSGetForkSize(id->refNum, pSize) != noErr){ # else if( GetEOF(id->refNum, pSize) != noErr ){ # endif return SQLITE_IOERR; }else{ return SQLITE_OK; } #endif } #if OS_WIN /* ** Return true (non-zero) if we are running under WinNT, Win2K or WinXP. ** Return false (zero) for Win95, Win98, or WinME. ** ** Here is an interesting observation: Win95, Win98, and WinME lack ** the LockFileEx() API. But we can still statically link against that ** API as long as we don't call it win running Win95/98/ME. A call to ** this routine is used to determine if the host is Win95/98/ME or ** WinNT/2K/XP so that we will know whether or not we can safely call ** the LockFileEx() API. */ int isNT(void){ static osType = 0; /* 0=unknown 1=win95 2=winNT */ if( osType==0 ){ OSVERSIONINFO sInfo; sInfo.dwOSVersionInfoSize = sizeof(sInfo); GetVersionEx(&sInfo); osType = sInfo.dwPlatformId==VER_PLATFORM_WIN32_NT ? 2 : 1; } return osType==2; } #endif /* ** Windows file locking notes: [similar issues apply to MacOS] ** ** 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. ** (This is a design error on the part of Windows, but there is nothing ** we can do about that.) So the region used for locking is at the ** end of the file where it is unlikely to ever interfere with an ** actual read attempt. ** ** A database read 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. ** A database write lock is obtained by locking all bytes in the range. ** There can only be one writer. ** ** A lock is obtained on the first byte of the lock range before acquiring ** either a read lock or a write lock. This prevents two processes from ** attempting to get a lock at a same time. The semantics of ** sqliteOsReadLock() require that if there is already a write lock, that ** lock is converted into a read lock atomically. The lock on the first ** byte allows us to drop the old write lock and get the read lock without ** another process jumping into the middle and messing us up. The same ** argument applies to sqliteOsWriteLock(). ** ** 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. ** ** Note: On MacOS we use the resource fork for locking. ** ** The following #defines specify the range of bytes used for locking. ** N_LOCKBYTE is the number of bytes available for doing the locking. ** The first byte used to hold the lock while the lock is changing does ** not count toward this number. FIRST_LOCKBYTE is the address of ** the first byte in the range of bytes used for locking. */ #define N_LOCKBYTE 10239 #if OS_MAC # define FIRST_LOCKBYTE (0x000fffff - N_LOCKBYTE) #else # define FIRST_LOCKBYTE (0xffffffff - N_LOCKBYTE) #endif /* ** Change the status of the lock on the file "id" to be a readlock. ** If the file was write locked, then this reduces the lock to a read. ** If the file was read locked, then this acquires a new read lock. ** ** Return SQLITE_OK on success and SQLITE_BUSY on failure. If this ** library was compiled with large file support (LFS) but LFS is not ** available on the host, then an SQLITE_NOLFS is returned. */ int sqliteOsReadLock(OsFile *id){ #if OS_UNIX int rc; sqliteOsEnterMutex(); if( id->pLock->cnt>0 ){ if( !id->locked ){ id->pLock->cnt++; id->locked = 1; } rc = SQLITE_OK; }else if( id->locked || id->pLock->cnt==0 ){ struct flock lock; int s; lock.l_type = F_RDLCK; lock.l_whence = SEEK_SET; lock.l_start = lock.l_len = 0L; s = fcntl(id->fd, F_SETLK, &lock); if( s!=0 ){ rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; }else{ rc = SQLITE_OK; id->pLock->cnt = 1; id->locked = 1; } }else{ rc = SQLITE_BUSY; } sqliteOsLeaveMutex(); return rc; #endif #if OS_WIN int rc; if( id->locked>0 ){ rc = SQLITE_OK; }else{ int lk = (sqliteRandomInteger() & 0x7ffffff)%N_LOCKBYTE+1; int res; int cnt = 100; while( cnt-->0 && (res = LockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0))==0 ){ Sleep(1); } if( res ){ UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0); if( isNT() ){ OVERLAPPED ovlp; ovlp.Offset = FIRST_LOCKBYTE+1; ovlp.OffsetHigh = 0; ovlp.hEvent = 0; res = LockFileEx(id->h, LOCKFILE_FAIL_IMMEDIATELY, 0, N_LOCKBYTE, 0, &ovlp); }else{ res = LockFile(id->h, FIRST_LOCKBYTE+lk, 0, 1, 0); } UnlockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0); } if( res ){ id->locked = lk; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } } return rc; #endif #if OS_MAC int rc; if( id->locked>0 || id->refNumRF == -1 ){ rc = SQLITE_OK; }else{ int lk = (sqliteRandomInteger() & 0x7ffffff)%N_LOCKBYTE+1; OSErr res; int cnt = 5; ParamBlockRec params; memset(¶ms, 0, sizeof(params)); params.ioParam.ioRefNum = id->refNumRF; params.ioParam.ioPosMode = fsFromStart; params.ioParam.ioPosOffset = FIRST_LOCKBYTE; params.ioParam.ioReqCount = 1; while( cnt-->0 && (res = PBLockRangeSync(¶ms))!=noErr ){ UInt32 finalTicks; Delay(1, &finalTicks); /* 1/60 sec */ } if( res == noErr ){ params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1; params.ioParam.ioReqCount = N_LOCKBYTE; PBUnlockRangeSync(¶ms); params.ioParam.ioPosOffset = FIRST_LOCKBYTE+lk; params.ioParam.ioReqCount = 1; res = PBLockRangeSync(¶ms); params.ioParam.ioPosOffset = FIRST_LOCKBYTE; params.ioParam.ioReqCount = 1; PBUnlockRangeSync(¶ms); } if( res == noErr ){ id->locked = lk; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } } return rc; #endif } /* ** Change the lock status to be an exclusive or write lock. Return ** SQLITE_OK on success and SQLITE_BUSY on a failure. If this ** library was compiled with large file support (LFS) but LFS is not ** available on the host, then an SQLITE_NOLFS is returned. */ int sqliteOsWriteLock(OsFile *id){ #if OS_UNIX int rc; sqliteOsEnterMutex(); if( id->pLock->cnt==0 || (id->pLock->cnt==1 && id->locked==1) ){ struct flock lock; int s; lock.l_type = F_WRLCK; lock.l_whence = SEEK_SET; lock.l_start = lock.l_len = 0L; s = fcntl(id->fd, F_SETLK, &lock); if( s!=0 ){ rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; }else{ rc = SQLITE_OK; id->pLock->cnt = -1; id->locked = 1; } }else{ rc = SQLITE_BUSY; } sqliteOsLeaveMutex(); return rc; #endif #if OS_WIN int rc; if( id->locked<0 ){ rc = SQLITE_OK; }else{ int res; int cnt = 100; while( cnt-->0 && (res = LockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0))==0 ){ Sleep(1); } if( res ){ if( id->locked>0 ){ if( isNT() ){ UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0); }else{ res = UnlockFile(id->h, FIRST_LOCKBYTE + id->locked, 0, 1, 0); } } if( res ){ res = LockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0); }else{ res = 0; } UnlockFile(id->h, FIRST_LOCKBYTE, 0, 1, 0); } if( res ){ id->locked = -1; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } } return rc; #endif #if OS_MAC int rc; if( id->locked<0 || id->refNumRF == -1 ){ rc = SQLITE_OK; }else{ OSErr res; int cnt = 5; ParamBlockRec params; memset(¶ms, 0, sizeof(params)); params.ioParam.ioRefNum = id->refNumRF; params.ioParam.ioPosMode = fsFromStart; params.ioParam.ioPosOffset = FIRST_LOCKBYTE; params.ioParam.ioReqCount = 1; while( cnt-->0 && (res = PBLockRangeSync(¶ms))!=noErr ){ UInt32 finalTicks; Delay(1, &finalTicks); /* 1/60 sec */ } if( res == noErr ){ params.ioParam.ioPosOffset = FIRST_LOCKBYTE + id->locked; params.ioParam.ioReqCount = 1; if( id->locked==0 || PBUnlockRangeSync(¶ms)==noErr ){ params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1; params.ioParam.ioReqCount = N_LOCKBYTE; res = PBLockRangeSync(¶ms); }else{ res = afpRangeNotLocked; } params.ioParam.ioPosOffset = FIRST_LOCKBYTE; params.ioParam.ioReqCount = 1; PBUnlockRangeSync(¶ms); } if( res == noErr ){ id->locked = -1; rc = SQLITE_OK; }else{ rc = SQLITE_BUSY; } } return rc; #endif } /* ** Unlock the given file descriptor. If the file descriptor was ** not previously locked, then this routine is a no-op. If this ** library was compiled with large file support (LFS) but LFS is not ** available on the host, then an SQLITE_NOLFS is returned. */ int sqliteOsUnlock(OsFile *id){ #if OS_UNIX int rc; if( !id->locked ) return SQLITE_OK; sqliteOsEnterMutex(); assert( id->pLock->cnt!=0 ); if( id->pLock->cnt>1 ){ id->pLock->cnt--; rc = SQLITE_OK; }else{ struct flock lock; int s; lock.l_type = F_UNLCK; lock.l_whence = SEEK_SET; lock.l_start = lock.l_len = 0L; s = fcntl(id->fd, F_SETLK, &lock); if( s!=0 ){ rc = (errno==EINVAL) ? SQLITE_NOLFS : SQLITE_BUSY; }else{ rc = SQLITE_OK; id->pLock->cnt = 0; } } sqliteOsLeaveMutex(); id->locked = 0; return rc; #endif #if OS_WIN int rc; if( id->locked==0 ){ rc = SQLITE_OK; }else if( isNT() || id->locked<0 ){ UnlockFile(id->h, FIRST_LOCKBYTE+1, 0, N_LOCKBYTE, 0); rc = SQLITE_OK; id->locked = 0; }else{ UnlockFile(id->h, FIRST_LOCKBYTE+id->locked, 0, 1, 0); rc = SQLITE_OK; id->locked = 0; } return rc; #endif #if OS_MAC int rc; ParamBlockRec params; memset(¶ms, 0, sizeof(params)); params.ioParam.ioRefNum = id->refNumRF; params.ioParam.ioPosMode = fsFromStart; if( id->locked==0 || id->refNumRF == -1 ){ rc = SQLITE_OK; }else if( id->locked<0 ){ params.ioParam.ioPosOffset = FIRST_LOCKBYTE+1; params.ioParam.ioReqCount = N_LOCKBYTE; PBUnlockRangeSync(¶ms); rc = SQLITE_OK; id->locked = 0; }else{ params.ioParam.ioPosOffset = FIRST_LOCKBYTE+id->locked; params.ioParam.ioReqCount = 1; PBUnlockRangeSync(¶ms); rc = SQLITE_OK; id->locked = 0; } return rc; #endif } /* ** Get information to seed the random number generator. The seed ** is written into the buffer zBuf[256]. The calling function must ** supply a sufficiently large buffer. */ int sqliteOsRandomSeed(char *zBuf){ #ifdef SQLITE_TEST /* When testing, always use the same random number sequence. ** This makes the tests repeatable. */ memset(zBuf, 0, 256); #endif #if OS_UNIX && !defined(SQLITE_TEST) int pid; time((time_t*)zBuf); pid = getpid(); memcpy(&zBuf[sizeof(time_t)], &pid, sizeof(pid)); #endif #if OS_WIN && !defined(SQLITE_TEST) GetSystemTime((LPSYSTEMTIME)zBuf); #endif #if OS_MAC int pid; Microseconds((UnsignedWide*)zBuf); pid = getpid(); memcpy(&zBuf[sizeof(UnsignedWide)], &pid, sizeof(pid)); #endif return SQLITE_OK; } /* ** Sleep for a little while. Return the amount of time slept. */ int sqliteOsSleep(int ms){ #if OS_UNIX #if defined(HAVE_USLEEP) && HAVE_USLEEP usleep(ms*1000); return ms; #else sleep((ms+999)/1000); return 1000*((ms+999)/1000); #endif #endif #if OS_WIN Sleep(ms); return ms; #endif #if OS_MAC UInt32 finalTicks; UInt32 ticks = (((UInt32)ms+16)*3)/50; /* 1/60 sec per tick */ Delay(ticks, &finalTicks); return (int)((ticks*50)/3); #endif } /* ** Macros used to determine whether or not to use threads. The ** SQLITE_UNIX_THREADS macro is defined if we are synchronizing for ** Posix threads and SQLITE_W32_THREADS is defined if we are ** synchronizing using Win32 threads. */ #if OS_UNIX && defined(THREADSAFE) && THREADSAFE # include # define SQLITE_UNIX_THREADS 1 #endif #if OS_WIN && defined(THREADSAFE) && THREADSAFE # define SQLITE_W32_THREADS 1 #endif #if OS_MAC && defined(THREADSAFE) && THREADSAFE # include # define SQLITE_MACOS_MULTITASKING 1 #endif /* ** Static variables used for thread synchronization */ static int inMutex = 0; #ifdef SQLITE_UNIX_THREADS static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; #endif #ifdef SQLITE_W32_THREADS static CRITICAL_SECTION cs; #endif #ifdef SQLITE_MACOS_MULTITASKING static MPCriticalRegionID criticalRegion; #endif /* ** The following pair of routine implement mutual exclusion for ** multi-threaded processes. Only a single thread is allowed to ** executed code that is surrounded by EnterMutex() and LeaveMutex(). ** ** SQLite uses only a single Mutex. There is not much critical ** code and what little there is executes quickly and without blocking. */ void sqliteOsEnterMutex(){ #ifdef SQLITE_UNIX_THREADS pthread_mutex_lock(&mutex); #endif #ifdef SQLITE_W32_THREADS static int isInit = 0; while( !isInit ){ static long lock = 0; if( InterlockedIncrement(&lock)==1 ){ InitializeCriticalSection(&cs); isInit = 1; }else{ Sleep(1); } } EnterCriticalSection(&cs); #endif #ifdef SQLITE_MACOS_MULTITASKING static volatile int notInit = 1; if( notInit ){ if( notInit == 2 ) /* as close as you can get to thread safe init */ MPYield(); else{ notInit = 2; MPCreateCriticalRegion(&criticalRegion); notInit = 0; } } MPEnterCriticalRegion(criticalRegion, kDurationForever); #endif assert( !inMutex ); inMutex = 1; } void sqliteOsLeaveMutex(){ assert( inMutex ); inMutex = 0; #ifdef SQLITE_UNIX_THREADS pthread_mutex_unlock(&mutex); #endif #ifdef SQLITE_W32_THREADS LeaveCriticalSection(&cs); #endif #ifdef SQLITE_MACOS_MULTITASKING MPExitCriticalRegion(criticalRegion); #endif } /* ** Turn a relative pathname into a full pathname. Return a pointer ** to the full pathname stored in space obtained from sqliteMalloc(). ** The calling function is responsible for freeing this space once it ** is no longer needed. */ char *sqliteOsFullPathname(const char *zRelative){ #if OS_UNIX char *zFull = 0; if( zRelative[0]=='/' ){ sqliteSetString(&zFull, zRelative, (char*)0); }else{ char zBuf[5000]; sqliteSetString(&zFull, getcwd(zBuf, sizeof(zBuf)), "/", zRelative, (char*)0); } return zFull; #endif #if OS_WIN char *zNotUsed; char *zFull; int nByte; nByte = GetFullPathName(zRelative, 0, 0, &zNotUsed) + 1; zFull = sqliteMalloc( nByte ); if( zFull==0 ) return 0; GetFullPathName(zRelative, nByte, zFull, &zNotUsed); return zFull; #endif #if OS_MAC char *zFull = 0; if( zRelative[0]==':' ){ char zBuf[_MAX_PATH+1]; sqliteSetString(&zFull, getcwd(zBuf, sizeof(zBuf)), &(zRelative[1]), (char*)0); }else{ if( strchr(zRelative, ':') ){ sqliteSetString(&zFull, zRelative, (char*)0); }else{ char zBuf[_MAX_PATH+1]; sqliteSetString(&zFull, getcwd(zBuf, sizeof(zBuf)), zRelative, (char*)0); } } return zFull; #endif } /* ** Find the current time (in Universal Coordinated Time). Write the ** current time and date as a Julian Day number into *prNow and ** return 0. Return 1 if the time and date cannot be found. */ int sqliteOsCurrentTime(double *prNow){ #if OS_UNIX time_t t; time(&t); *prNow = t/86400.0 + 2440587.5; return 0; #endif #if OS_WIN FILETIME ft; /* FILETIME structure is a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (= JD 2305813.5). */ double now; GetSystemTimeAsFileTime( &ft ); now = ((double)ft.dwHighDateTime) * 4294967296.0; *prNow = (now + ft.dwLowDateTime)/864000000000.0 + 2305813.5; #endif return 0; return 1; }