DBD-SQLcipher
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#define osStat ((int(*)(const char*,struct stat*))aSyscall[4].pCurrent)/*** The DJGPP compiler environment looks mostly like Unix, but it** lacks thefcntl()systemcall. So redefinefcntl() to be something** that always succeeds. This means that locking does not occur under** DJGPP. But it is DOS - what did you expect?*/#ifdef __DJGPP__{"fstat", 0, 0 },#define osFstat(a,b,c) 0#else{"fstat", (sqlite3_syscall_ptr)fstat, 0 },#define osFstat ((int(*)(int,struct stat*))aSyscall[5].pCurrent)#endif{"ftruncate", (sqlite3_syscall_ptr)ftruncate, 0 },#define osFtruncate ((int(*)(int,off_t))aSyscall[6].pCurrent){"fcntl", (sqlite3_syscall_ptr)fcntl, 0 },#define osFcntl ((int(*)(int,int,...))aSyscall[7].pCurrent)
if( fd>=SQLITE_MINIMUM_FILE_DESCRIPTOR ) break;osClose(fd);sqlite3_log(SQLITE_WARNING,"attempt to open \"%s\" as file descriptor %d", z, fd);fd = -1;if( osOpen("/dev/null", f, m)<0 ) break;}if( fd>=0 ){if( m!=0 ){structstatstatbuf;if( osFstat(fd,&statbuf)==0&& statbuf.st_size==0&& (statbuf.st_mode&0777)!=m){osFchmod(fd, m);}}#if defined(FD_CLOEXEC) && (!defined(O_CLOEXEC) || O_CLOEXEC==0)osFcntl(fd, F_SETFD, osFcntl(fd, F_GETFD, 0) | FD_CLOEXEC);#endif}
** file descriptors opened on different file names.**** among competing threads of the same process. POSIX locks will work fine** to synchronize accessforthreads in separate processes, but not** threads within the same process.**** To workaroundthe problem, SQLitehasto 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 thestatstructure that fstat() fills in)** and checkforlocks already existing on that inode. When locks are** created or removed, we have to look atourown internal record of the** locks to seeifanother threadhaspreviously set alockon that same** inode.**** canonical filename and implemented in the previous division.)**** The sqlite3_file structureforPOSIX isnolonger just an integer file
struct unixFileId fileId; /* Lookup keyforthe unixInodeInfo */structstatstatbuf; /* Low-level file information */unixInodeInfo*pInode= 0; /* Candidate unixInodeInfo object */assert( unixMutexHeld() );/* Get low-level information about the file that we can used to** create a unique nameforthe file.*/fd = pFile->h;rc = osFstat(fd,&statbuf);if( rc!=0 ){pFile->lastErrno = errno;#ifdef EOVERFLOWif( pFile->lastErrno==EOVERFLOW )returnSQLITE_NOLFS;#endifreturnSQLITE_IOERR;}#ifdef __APPLE__/* On OS X on an msdos filesystem, the inode number is reported
** in the header of every SQLite database. In this way,ifthere** is a race condition such that another threadhasalready populated** the first page of the database,nodamage is done.*/if( statbuf.st_size==0 && (pFile->fsFlags & SQLITE_FSFLAGS_IS_MSDOS)!=0 ){do{ rc = osWrite(fd,"S", 1); }while( rc<0 && errno==EINTR );if( rc!=1 ){pFile->lastErrno = errno;returnSQLITE_IOERR;}rc = osFstat(fd,&statbuf);if( rc!=0 ){pFile->lastErrno = errno;returnSQLITE_IOERR;}}#endifmemset(&fileId, 0, sizeof(fileId));fileId.dev = statbuf.st_dev;#if OS_VXWORKS
** Issue sqlite3_log(SQLITE_WARNING,...) messagesifanything is not right.*/static void verifyDbFile(unixFile*pFile){structstatbuf;intrc;if( pFile->ctrlFlags & UNIXFILE_WARNED ){/* One or more of the following warnings have already been issued. Do not** repeat them so as not to clutter the errorlog*/return;}rc = osFstat(pFile->h,&buf);if( rc!=0 ){sqlite3_log(SQLITE_WARNING,"cannot fstat db file %s", pFile->zPath);pFile->ctrlFlags |= UNIXFILE_WARNED;return;}if( buf.st_nlink==0 && (pFile->ctrlFlags & UNIXFILE_DELETE)==0 ){sqlite3_log(SQLITE_WARNING,"file unlinked while open: %s", pFile->zPath);pFile->ctrlFlags |= UNIXFILE_WARNED;return;}
}}/*** Determine the current size of a file in bytes*/staticintunixFileSize(sqlite3_file*id, i64*pSize){intrc;structstatbuf;assert( id );rc = osFstat(((unixFile*)id)->h,&buf);SimulateIOError( rc=1 );if( rc!=0 ){((unixFile*)id)->lastErrno = errno;returnSQLITE_IOERR_FSTAT;}*pSize= buf.st_size;/* When opening a zero-size database, the findInodeInfo() procedure** writes a single byte into that file in order to workarounda bug** in the OS-X msdos filesystem. In order to avoid problemswithupper
/*** This function is called to handle the SQLITE_FCNTL_SIZE_HINT** file-control operation. Enlarge the database to nBytes in size** (rounded up to thenextchunk-size). If the database is already** nBytes or larger, this routine is ano-op.*/staticintfcntlSizeHint(unixFile*pFile, i64 nByte){if( pFile->szChunk>0 ){i64 nSize; /* Required file size */structstatbuf; /* Used to holdreturnvaluesof fstat() */if( osFstat(pFile->h,&buf) )returnSQLITE_IOERR_FSTAT;nSize = ((nByte+pFile->szChunk-1) / pFile->szChunk) * pFile->szChunk;if( nSize>(i64)buf.st_size ){#if defined(HAVE_POSIX_FALLOCATE) && HAVE_POSIX_FALLOCATE/* The code below is handling thereturnvalue of osFallocate()** correctly. posix_fallocate() isdefinedto "returns zero on success,** or an error number on failure". See the manpagefordetails. */interr;do{
memset(p, 0, sizeof(*p));assert( pDbFd->pShm==0 );/* Check to seeifa unixShmNode object alreadyexists. Reuse an existing** oneifpresent. Create a new oneifnecessary.*/unixEnterMutex();pInode = pDbFd->pInode;pShmNode = pInode->pShmNode;if( pShmNode==0 ){structstatsStat; /* fstat() infofordatabase file *//* Call fstat() to figure out the permissions on the database file. If** a new *-shm file is created, an attempt will be made to create it**withthe same permissions.*/if( osFstat(pDbFd->h,&sStat) && pInode->bProcessLock==0 ){rc = SQLITE_IOERR_FSTAT;gotoshm_open_err;}#ifdef SQLITE_SHM_DIRECTORYnShmFilename = sizeof(SQLITE_SHM_DIRECTORY) + 31;#elsenShmFilename = 6 + (int)strlen(pDbFd->zPath);#endifpShmNode = sqlite3_malloc( sizeof(*pShmNode) + nShmFilename );
assert( pShmNode->pInode==pDbFd->pInode );assert( pShmNode->h>=0 || pDbFd->pInode->bProcessLock==1 );assert( pShmNode->h<0 || pDbFd->pInode->bProcessLock==0 );/* Minimum number of regions required to be mapped. */nReqRegion = ((iRegion+nShmPerMap) / nShmPerMap) * nShmPerMap;if( pShmNode->nRegion<nReqRegion ){char **apNew; /* New apRegion[] array */intnByte = nReqRegion*szRegion; /* Minimum required file size */structstatsStat; /* Used by fstat() */pShmNode->szRegion = szRegion;if( pShmNode->h>=0 ){/* The requested region is not mapped into this processes address space.** Check to seeifithasbeen allocated (i.e.ifthe wal-indexfile is** large enough to contain the requested region).*/if( osFstat(pShmNode->h,&sStat) ){rc = SQLITE_IOERR_SHMSIZE;gotoshmpage_out;}if( sStat.st_size<nByte ){/* The requested memory region does not exist. If bExtend is set to** false,exitearly.*ppwill be set to NULL and SQLITE_OK returned.*/if( !bExtend ){gotoshmpage_out;
*/staticintunixMapfile(unixFile*pFd, i64 nByte){i64 nMap = nByte;intrc;assert( nMap>=0 || pFd->nFetchOut==0 );if( pFd->nFetchOut>0 )returnSQLITE_OK;if( nMap<0 ){structstatstatbuf; /* Low-level file information */rc = osFstat(pFd->h,&statbuf);if( rc!=SQLITE_OK ){returnSQLITE_IOERR_FSTAT;}nMap = statbuf.st_size;}if( nMap>pFd->mmapSizeMax ){nMap = pFd->mmapSizeMax;}if( nMap!=pFd->mmapSize ){
|| pLockingStyle ==&nfsIoMethods#endif){unixEnterMutex();rc = findInodeInfo(pNew,&pNew->pInode);if( rc!=SQLITE_OK ){/* If an error occurred in findInodeInfo(),closethe file descriptor** immediately,beforereleasing the mutex. findInodeInfo() may fail** in two scenarios:**** (a) A call to fstat() failed.** (b) A malloc failed.**** Scenario (b) may only occurifthe process is holdingnoother** file descriptorsopenon the same file. If there were other file** descriptors on this file, thennomalloc would be required by** findInodeInfo(). If this is the case, it is quite safe toclose** handle h - as it is guaranteed thatnoposix locks will be released** by doing so.**** If scenario (a) caused the error then things are not so safe. The** implicit assumption here is thatiffstat() fails, things are in** such bad shape that dropping alockor two doesn't matter much.*/robust_close(pNew, h, __LINE__);h = -1;}unixLeaveMutex();}#if SQLITE_ENABLE_LOCKING_STYLE && defined(__APPLE__)elseif( pLockingStyle ==&afpIoMethods){
*/static UnixUnusedFd*findReusableFd(const char*zPath,intflags){UnixUnusedFd*pUnused= 0;/* Do not searchforan unused file descriptor on vxworks. Not because** vxworks would not benefit from the change (it might, we're not sure),** but becausenoway to test it is currently available. It is better** not to risk breaking vxworks supportforthe sake of such an obscure** feature. */#if !OS_VXWORKSstructstatsStat; /* Results ofstat() call *//* Astat() call may failforvarious reasons. If this happens, it is** almost certain that anopen() call on the same path will also fail.** For this reason,ifan error occurs in thestat() call here, it is** ignored and -1 is returned. Thecallerwilltrytoopena new file** descriptor on the same path, fail, andreturnan error to SQLite.**** Evenifa subsequentopen() call does succeed, the consequences of** not searchingfora reusable file descriptor are not dire. */if( 0==osStat(zPath,&sStat) ){unixInodeInfo*pInode;unixEnterMutex();pInode = inodeList;
uid_t*pUid, /* OUT: uid to set on the file */gid_t*pGid/* OUT: gid to set on the file */){intrc = SQLITE_OK; /* Return Code */*pMode= 0;*pUid= 0;*pGid= 0;if( flags & (SQLITE_OPEN_WAL|SQLITE_OPEN_MAIN_JOURNAL) ){char zDb[MAX_PATHNAME+1]; /* Database file path */intnDb; /* Number of valid bytes in zDb */structstatsStat; /* Output ofstat() on database file *//* zPath is a path to a WAL or journal file. The following block derives** the path to the associated database file from zPath. This block handles** the following naming conventions:****"<path to db>-journal"**"<path to db>-wal"**"<path to db>-journalNN"**"<path to db>-walNN"**
rc = conchFile->pMethod->xLock((sqlite3_file*)conchFile, lockType);nTries ++;if( rc==SQLITE_BUSY ){/* If thelockfailed (busy):* 1sttry: get the modtimeof the conch,wait0.5s andtryagain.* 2ndtry: failifthe modtimechanged or host id is different,wait* 10 sec andtryagain* 3rdtry: break thelockunlessthe modtimehaschanged.*/structstatbuf;if( osFstat(conchFile->h,&buf) ){pFile->lastErrno = errno;returnSQLITE_IOERR_LOCK;}if( nTries==1 ){conchModTime = buf.st_mtimespec;usleep(500000); /*wait0.5 sec andtrythelockagain*/continue;}
}writeSize = PROXY_PATHINDEX + strlen(&writeBuffer[PROXY_PATHINDEX]);robust_ftruncate(conchFile->h, writeSize);rc = unixWrite((sqlite3_file *)conchFile, writeBuffer, writeSize, 0);fsync(conchFile->h);/* If we created a new conch file (not just updated the contents of a** valid conch file),tryto match the permissions of the database*/if( rc==SQLITE_OK && createConch ){structstatbuf;interr = osFstat(pFile->h,&buf);if( err==0 ){mode_t cmode = buf.st_mode&(S_IRUSR|S_IWUSR | S_IRGRP|S_IWGRP |S_IROTH|S_IWOTH);/*tryto match the database file R/W permissions, ignore failure */#ifndef SQLITE_PROXY_DEBUGosFchmod(conchFile->h, cmode);#elsedo{rc = osFchmod(conchFile->h, cmode);}while( rc==(-1) && errno==EINTR );
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