/* ** Parameter zSrcData points to a buffer containing the data for ** page iSrcPg from the source database. Copy this data into the ** destination database. */ static int backupOnePage( sqlite3_backup *p, /* Backup handle */ Pgno iSrcPg, /* Source database page to backup */ const u8 *zSrcData, /* Source database page data */ int bUpdate /* True for an update, false otherwise */ ){ Pager * const pDestPager = sqlite3BtreePager(p->pDest); const int nSrcPgsz = sqlite3BtreeGetPageSize(p->pSrc); int nDestPgsz = sqlite3BtreeGetPageSize(p->pDest); const int nCopy = MIN(nSrcPgsz, nDestPgsz); const i64 iEnd = (i64)iSrcPg*(i64)nSrcPgsz; #ifdef SQLITE_HAS_CODEC /* Use BtreeGetReserveNoMutex() for the source b-tree, as although it is ** guaranteed that the shared-mutex is held by this thread, handle ** p->pSrc may not actually be the owner. */ int nSrcReserve = sqlite3BtreeGetReserveNoMutex(p->pSrc); int nDestReserve = sqlite3BtreeGetOptimalReserve(p->pDest); #endif int rc = SQLITE_OK; i64 iOff; assert( sqlite3BtreeGetReserveNoMutex(p->pSrc)>=0 ); assert( p->bDestLocked ); assert( !isFatalError(p->rc) ); assert( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ); assert( zSrcData ); /* Catch the case where the destination is an in-memory database and the ** page sizes of the source and destination differ. */ if( nSrcPgsz!=nDestPgsz && sqlite3PagerIsMemdb(pDestPager) ){ rc = SQLITE_READONLY; } #ifdef SQLITE_HAS_CODEC /* Backup is not possible if the page size of the destination is changing ** and a codec is in use. */ if( nSrcPgsz!=nDestPgsz && sqlite3PagerGetCodec(pDestPager)!=0 ){ rc = SQLITE_READONLY; } /* Backup is not possible if the number of bytes of reserve space differ ** between source and destination. If there is a difference, try to ** fix the destination to agree with the source. If that is not possible, ** then the backup cannot proceed. */ if( nSrcReserve!=nDestReserve ){ u32 newPgsz = nSrcPgsz; rc = sqlite3PagerSetPagesize(pDestPager, &newPgsz, nSrcReserve); if( rc==SQLITE_OK && newPgsz!=nSrcPgsz ) rc = SQLITE_READONLY; } #endif /* This loop runs once for each destination page spanned by the source ** page. For each iteration, variable iOff is set to the byte offset ** of the destination page. */ for(iOff=iEnd-(i64)nSrcPgsz; rc==SQLITE_OK && iOff<iEnd; iOff+=nDestPgsz){ DbPage *pDestPg = 0; Pgno iDest = (Pgno)(iOff/nDestPgsz)+1; if( iDest==PENDING_BYTE_PAGE(p->pDest->pBt) ) continue; if( SQLITE_OK==(rc = sqlite3PagerGet(pDestPager, iDest, &pDestPg, 0)) && SQLITE_OK==(rc = sqlite3PagerWrite(pDestPg)) ){ const u8 *zIn = &zSrcData[iOff%nSrcPgsz]; u8 *zDestData = sqlite3PagerGetData(pDestPg); u8 *zOut = &zDestData[iOff%nDestPgsz]; /* Copy the data from the source page into the destination page. ** Then clear the Btree layer MemPage.isInit flag. Both this module ** and the pager code use this trick (clearing the first byte ** of the page 'extra' space to invalidate the Btree layers ** cached parse of the page). MemPage.isInit is marked ** "MUST BE FIRST" for this purpose. */ memcpy(zOut, zIn, nCopy); ((u8 *)sqlite3PagerGetExtra(pDestPg))[0] = 0; if( iOff==0 && bUpdate==0 ){ sqlite3Put4byte(&zOut[28], sqlite3BtreeLastPage(p->pSrc)); } } sqlite3PagerUnref(pDestPg); } return rc; }
/* ** An SQL user-function registered to do the work of an ATTACH statement. The ** three arguments to the function come directly from an attach statement: ** ** ATTACH DATABASE x AS y KEY z ** ** SELECT sqlite_attach(x, y, z) ** ** If the optional "KEY z" syntax is omitted, an SQL NULL is passed as the ** third argument. */ static void attachFunc( sqlite3_context *context, int NotUsed, sqlite3_value **argv ){ int i; int rc = 0; sqlite3 *db = sqlite3_context_db_handle(context); const char *zName; const char *zFile; char *zPath = 0; char *zErr = 0; unsigned int flags; Db *aNew; char *zErrDyn = 0; sqlite3_vfs *pVfs; UNUSED_PARAMETER(NotUsed); zFile = (const char *)sqlite3_value_text(argv[0]); zName = (const char *)sqlite3_value_text(argv[1]); if( zFile==0 ) zFile = ""; if( zName==0 ) zName = ""; /* Check for the following errors: ** ** * Too many attached databases, ** * Transaction currently open ** * Specified database name already being used. */ if( db->nDb>=db->aLimit[SQLITE_LIMIT_ATTACHED]+2 ){ zErrDyn = sqlite3MPrintf(db, "too many attached databases - max %d", db->aLimit[SQLITE_LIMIT_ATTACHED] ); goto attach_error; } if( !db->autoCommit ){ zErrDyn = sqlite3MPrintf(db, "cannot ATTACH database within transaction"); goto attach_error; } for(i=0; i<db->nDb; i++){ char *z = db->aDb[i].zName; assert( z && zName ); if( sqlite3StrICmp(z, zName)==0 ){ zErrDyn = sqlite3MPrintf(db, "database %s is already in use", zName); goto attach_error; } } /* Allocate the new entry in the db->aDb[] array and initialize the schema ** hash tables. */ if( db->aDb==db->aDbStatic ){ aNew = sqlite3DbMallocRaw(db, sizeof(db->aDb[0])*3 ); if( aNew==0 ) return; memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2); }else{ aNew = sqlite3DbRealloc(db, db->aDb, sizeof(db->aDb[0])*(db->nDb+1) ); if( aNew==0 ) return; } db->aDb = aNew; aNew = &db->aDb[db->nDb]; memset(aNew, 0, sizeof(*aNew)); /* Open the database file. If the btree is successfully opened, use ** it to obtain the database schema. At this point the schema may ** or may not be initialized. */ flags = db->openFlags; rc = sqlite3ParseUri(db->pVfs->zName, zFile, &flags, &pVfs, &zPath, &zErr); if( rc!=SQLITE_OK ){ if( rc==SQLITE_NOMEM ) db->mallocFailed = 1; sqlite3_result_error(context, zErr, -1); sqlite3_free(zErr); return; } assert( pVfs ); flags |= SQLITE_OPEN_MAIN_DB; rc = sqlite3BtreeOpen(pVfs, zPath, db, &aNew->pBt, 0, flags); sqlite3_free( zPath ); db->nDb++; if( rc==SQLITE_CONSTRAINT ){ rc = SQLITE_ERROR; zErrDyn = sqlite3MPrintf(db, "database is already attached"); }else if( rc==SQLITE_OK ){ Pager *pPager; aNew->pSchema = sqlite3SchemaGet(db, aNew->pBt); if( !aNew->pSchema ){ rc = SQLITE_NOMEM; }else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){ zErrDyn = sqlite3MPrintf(db, "attached databases must use the same text encoding as main database"); rc = SQLITE_ERROR; } sqlite3BtreeEnter(aNew->pBt); pPager = sqlite3BtreePager(aNew->pBt); sqlite3PagerLockingMode(pPager, db->dfltLockMode); sqlite3BtreeSecureDelete(aNew->pBt, sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) ); #ifndef SQLITE_OMIT_PAGER_PRAGMAS sqlite3BtreeSetPagerFlags(aNew->pBt, 3 | (db->flags & PAGER_FLAGS_MASK)); #endif sqlite3BtreeLeave(aNew->pBt); } aNew->safety_level = 3; aNew->zName = sqlite3DbStrDup(db, zName); if( rc==SQLITE_OK && aNew->zName==0 ){ rc = SQLITE_NOMEM; } #ifdef SQLITE_HAS_CODEC if( rc==SQLITE_OK ){ extern int sqlite3CodecAttach(sqlite3*, int, const void*, int); extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*); int nKey; char *zKey; int t = sqlite3_value_type(argv[2]); switch( t ){ case SQLITE_INTEGER: case SQLITE_FLOAT: zErrDyn = sqlite3DbStrDup(db, "Invalid key value"); rc = SQLITE_ERROR; break; case SQLITE_TEXT: case SQLITE_BLOB: nKey = sqlite3_value_bytes(argv[2]); zKey = (char *)sqlite3_value_blob(argv[2]); rc = sqlite3CodecAttach(db, db->nDb-1, zKey, nKey); break; case SQLITE_NULL: /* No key specified. Use the key from the main database */ sqlite3CodecGetKey(db, 0, (void**)&zKey, &nKey); if( nKey>0 || sqlite3BtreeGetOptimalReserve(db->aDb[0].pBt)>0 ){ rc = sqlite3CodecAttach(db, db->nDb-1, zKey, nKey); } break; } } #endif /* If the file was opened successfully, read the schema for the new database. ** If this fails, or if opening the file failed, then close the file and ** remove the entry from the db->aDb[] array. i.e. put everything back the way ** we found it. */ if( rc==SQLITE_OK ){ sqlite3BtreeEnterAll(db); rc = sqlite3Init(db, &zErrDyn); sqlite3BtreeLeaveAll(db); } #ifdef SQLITE_USER_AUTHENTICATION if( rc==SQLITE_OK ){ u8 newAuth = 0; rc = sqlite3UserAuthCheckLogin(db, zName, &newAuth); if( newAuth<db->auth.authLevel ){ rc = SQLITE_AUTH_USER; } } #endif if( rc ){ int iDb = db->nDb - 1; assert( iDb>=2 ); if( db->aDb[iDb].pBt ){ sqlite3BtreeClose(db->aDb[iDb].pBt); db->aDb[iDb].pBt = 0; db->aDb[iDb].pSchema = 0; } sqlite3ResetAllSchemasOfConnection(db); db->nDb = iDb; if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){ db->mallocFailed = 1; sqlite3DbFree(db, zErrDyn); zErrDyn = sqlite3MPrintf(db, "out of memory"); }else if( zErrDyn==0 ){ zErrDyn = sqlite3MPrintf(db, "unable to open database: %s", zFile); } goto attach_error; } return; attach_error: /* Return an error if we get here */ if( zErrDyn ){ sqlite3_result_error(context, zErrDyn, -1); sqlite3DbFree(db, zErrDyn); } if( rc ) sqlite3_result_error_code(context, rc); }
/* ** This routine implements the OP_Vacuum opcode of the VDBE. */ int sqlite3RunVacuum( char **pzErrMsg, /* Write error message here */ sqlite3 *db, /* Database connection */ int iDb, /* Which attached DB to vacuum */ sqlite3_value *pOut /* Write results here, if not NULL */ ){ int rc = SQLITE_OK; /* Return code from service routines */ Btree *pMain; /* The database being vacuumed */ Btree *pTemp; /* The temporary database we vacuum into */ u32 saved_mDbFlags; /* Saved value of db->mDbFlags */ u64 saved_flags; /* Saved value of db->flags */ int saved_nChange; /* Saved value of db->nChange */ int saved_nTotalChange; /* Saved value of db->nTotalChange */ u8 saved_mTrace; /* Saved trace settings */ Db *pDb = 0; /* Database to detach at end of vacuum */ int isMemDb; /* True if vacuuming a :memory: database */ int nRes; /* Bytes of reserved space at the end of each page */ int nDb; /* Number of attached databases */ const char *zDbMain; /* Schema name of database to vacuum */ const char *zOut; /* Name of output file */ if( !db->autoCommit ){ sqlite3SetString(pzErrMsg, db, "cannot VACUUM from within a transaction"); return SQLITE_ERROR; } if( db->nVdbeActive>1 ){ sqlite3SetString(pzErrMsg, db,"cannot VACUUM - SQL statements in progress"); return SQLITE_ERROR; } if( pOut ){ if( sqlite3_value_type(pOut)!=SQLITE_TEXT ){ sqlite3SetString(pzErrMsg, db, "non-text filename"); return SQLITE_ERROR; } zOut = (const char*)sqlite3_value_text(pOut); }else{ zOut = ""; } /* Save the current value of the database flags so that it can be ** restored before returning. Then set the writable-schema flag, and ** disable CHECK and foreign key constraints. */ saved_flags = db->flags; saved_mDbFlags = db->mDbFlags; saved_nChange = db->nChange; saved_nTotalChange = db->nTotalChange; saved_mTrace = db->mTrace; db->flags |= SQLITE_WriteSchema | SQLITE_IgnoreChecks; db->mDbFlags |= DBFLAG_PreferBuiltin | DBFLAG_Vacuum; db->flags &= ~(u64)(SQLITE_ForeignKeys | SQLITE_ReverseOrder | SQLITE_Defensive | SQLITE_CountRows); db->mTrace = 0; zDbMain = db->aDb[iDb].zDbSName; pMain = db->aDb[iDb].pBt; isMemDb = sqlite3PagerIsMemdb(sqlite3BtreePager(pMain)); /* Attach the temporary database as 'vacuum_db'. The synchronous pragma ** can be set to 'off' for this file, as it is not recovered if a crash ** occurs anyway. The integrity of the database is maintained by a ** (possibly synchronous) transaction opened on the main database before ** sqlite3BtreeCopyFile() is called. ** ** An optimisation would be to use a non-journaled pager. ** (Later:) I tried setting "PRAGMA vacuum_db.journal_mode=OFF" but ** that actually made the VACUUM run slower. Very little journalling ** actually occurs when doing a vacuum since the vacuum_db is initially ** empty. Only the journal header is written. Apparently it takes more ** time to parse and run the PRAGMA to turn journalling off than it does ** to write the journal header file. */ nDb = db->nDb; rc = execSqlF(db, pzErrMsg, "ATTACH %Q AS vacuum_db", zOut); if( rc!=SQLITE_OK ) goto end_of_vacuum; assert( (db->nDb-1)==nDb ); pDb = &db->aDb[nDb]; assert( strcmp(pDb->zDbSName,"vacuum_db")==0 ); pTemp = pDb->pBt; if( pOut ){ sqlite3_file *id = sqlite3PagerFile(sqlite3BtreePager(pTemp)); i64 sz = 0; if( id->pMethods!=0 && (sqlite3OsFileSize(id, &sz)!=SQLITE_OK || sz>0) ){ rc = SQLITE_ERROR; sqlite3SetString(pzErrMsg, db, "output file already exists"); goto end_of_vacuum; } } nRes = sqlite3BtreeGetOptimalReserve(pMain); /* A VACUUM cannot change the pagesize of an encrypted database. */ #ifdef SQLITE_HAS_CODEC if( db->nextPagesize ){ extern void sqlite3CodecGetKey(sqlite3*, int, void**, int*); int nKey; char *zKey; sqlite3CodecGetKey(db, iDb, (void**)&zKey, &nKey); if( nKey ) db->nextPagesize = 0; } #endif sqlite3BtreeSetCacheSize(pTemp, db->aDb[iDb].pSchema->cache_size); sqlite3BtreeSetSpillSize(pTemp, sqlite3BtreeSetSpillSize(pMain,0)); sqlite3BtreeSetPagerFlags(pTemp, PAGER_SYNCHRONOUS_OFF|PAGER_CACHESPILL); /* Begin a transaction and take an exclusive lock on the main database ** file. This is done before the sqlite3BtreeGetPageSize(pMain) call below, ** to ensure that we do not try to change the page-size on a WAL database. */ rc = execSql(db, pzErrMsg, "BEGIN"); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = sqlite3BtreeBeginTrans(pMain, pOut==0 ? 2 : 0, 0); if( rc!=SQLITE_OK ) goto end_of_vacuum; /* Do not attempt to change the page size for a WAL database */ if( sqlite3PagerGetJournalMode(sqlite3BtreePager(pMain)) ==PAGER_JOURNALMODE_WAL ){ db->nextPagesize = 0; } if( sqlite3BtreeSetPageSize(pTemp, sqlite3BtreeGetPageSize(pMain), nRes, 0) || (!isMemDb && sqlite3BtreeSetPageSize(pTemp, db->nextPagesize, nRes, 0)) || NEVER(db->mallocFailed) ){ rc = SQLITE_NOMEM_BKPT; goto end_of_vacuum; } #ifndef SQLITE_OMIT_AUTOVACUUM sqlite3BtreeSetAutoVacuum(pTemp, db->nextAutovac>=0 ? db->nextAutovac : sqlite3BtreeGetAutoVacuum(pMain)); #endif /* Query the schema of the main database. Create a mirror schema ** in the temporary database. */ db->init.iDb = nDb; /* force new CREATE statements into vacuum_db */ rc = execSqlF(db, pzErrMsg, "SELECT sql FROM \"%w\".sqlite_master" " WHERE type='table'AND name<>'sqlite_sequence'" " AND coalesce(rootpage,1)>0", zDbMain ); if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = execSqlF(db, pzErrMsg, "SELECT sql FROM \"%w\".sqlite_master" " WHERE type='index'", zDbMain ); if( rc!=SQLITE_OK ) goto end_of_vacuum; db->init.iDb = 0; /* Loop through the tables in the main database. For each, do ** an "INSERT INTO vacuum_db.xxx SELECT * FROM main.xxx;" to copy ** the contents to the temporary database. */ rc = execSqlF(db, pzErrMsg, "SELECT'INSERT INTO vacuum_db.'||quote(name)" "||' SELECT*FROM\"%w\".'||quote(name)" "FROM vacuum_db.sqlite_master " "WHERE type='table'AND coalesce(rootpage,1)>0", zDbMain ); assert( (db->mDbFlags & DBFLAG_Vacuum)!=0 ); db->mDbFlags &= ~DBFLAG_Vacuum; if( rc!=SQLITE_OK ) goto end_of_vacuum; /* Copy the triggers, views, and virtual tables from the main database ** over to the temporary database. None of these objects has any ** associated storage, so all we have to do is copy their entries ** from the SQLITE_MASTER table. */ rc = execSqlF(db, pzErrMsg, "INSERT INTO vacuum_db.sqlite_master" " SELECT*FROM \"%w\".sqlite_master" " WHERE type IN('view','trigger')" " OR(type='table'AND rootpage=0)", zDbMain ); if( rc ) goto end_of_vacuum; /* At this point, there is a write transaction open on both the ** vacuum database and the main database. Assuming no error occurs, ** both transactions are closed by this block - the main database ** transaction by sqlite3BtreeCopyFile() and the other by an explicit ** call to sqlite3BtreeCommit(). */ { u32 meta; int i; /* This array determines which meta meta values are preserved in the ** vacuum. Even entries are the meta value number and odd entries ** are an increment to apply to the meta value after the vacuum. ** The increment is used to increase the schema cookie so that other ** connections to the same database will know to reread the schema. */ static const unsigned char aCopy[] = { BTREE_SCHEMA_VERSION, 1, /* Add one to the old schema cookie */ BTREE_DEFAULT_CACHE_SIZE, 0, /* Preserve the default page cache size */ BTREE_TEXT_ENCODING, 0, /* Preserve the text encoding */ BTREE_USER_VERSION, 0, /* Preserve the user version */ BTREE_APPLICATION_ID, 0, /* Preserve the application id */ }; assert( 1==sqlite3BtreeIsInTrans(pTemp) ); assert( pOut!=0 || 1==sqlite3BtreeIsInTrans(pMain) ); /* Copy Btree meta values */ for(i=0; i<ArraySize(aCopy); i+=2){ /* GetMeta() and UpdateMeta() cannot fail in this context because ** we already have page 1 loaded into cache and marked dirty. */ sqlite3BtreeGetMeta(pMain, aCopy[i], &meta); rc = sqlite3BtreeUpdateMeta(pTemp, aCopy[i], meta+aCopy[i+1]); if( NEVER(rc!=SQLITE_OK) ) goto end_of_vacuum; } if( pOut==0 ){ rc = sqlite3BtreeCopyFile(pMain, pTemp); } if( rc!=SQLITE_OK ) goto end_of_vacuum; rc = sqlite3BtreeCommit(pTemp); if( rc!=SQLITE_OK ) goto end_of_vacuum; #ifndef SQLITE_OMIT_AUTOVACUUM if( pOut==0 ){ sqlite3BtreeSetAutoVacuum(pMain, sqlite3BtreeGetAutoVacuum(pTemp)); } #endif } assert( rc==SQLITE_OK ); if( pOut==0 ){ rc = sqlite3BtreeSetPageSize(pMain, sqlite3BtreeGetPageSize(pTemp), nRes,1); } end_of_vacuum: /* Restore the original value of db->flags */ db->init.iDb = 0; db->mDbFlags = saved_mDbFlags; db->flags = saved_flags; db->nChange = saved_nChange; db->nTotalChange = saved_nTotalChange; db->mTrace = saved_mTrace; sqlite3BtreeSetPageSize(pMain, -1, -1, 1); /* Currently there is an SQL level transaction open on the vacuum ** database. No locks are held on any other files (since the main file ** was committed at the btree level). So it safe to end the transaction ** by manually setting the autoCommit flag to true and detaching the ** vacuum database. The vacuum_db journal file is deleted when the pager ** is closed by the DETACH. */ db->autoCommit = 1; if( pDb ){ sqlite3BtreeClose(pDb->pBt); pDb->pBt = 0; pDb->pSchema = 0; } /* This both clears the schemas and reduces the size of the db->aDb[] ** array. */ sqlite3ResetAllSchemasOfConnection(db); return rc; }