/* ** 2003 April 6 ** ** 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 used to implement the ATTACH and DETACH commands. */ #include "sqliteInt.h" #ifndef SQLITE_OMIT_ATTACH /* ** Resolve an expression that was part of an ATTACH or DETACH statement. This ** is slightly different from resolving a normal SQL expression, because simple ** identifiers are treated as strings, not possible column names or aliases. ** ** i.e. if the parser sees: ** ** ATTACH DATABASE abc AS def ** ** it treats the two expressions as literal strings 'abc' and 'def' instead of ** looking for columns of the same name. ** ** This only applies to the root node of pExpr, so the statement: ** ** ATTACH DATABASE abc||def AS 'db2' ** ** will fail because neither abc or def can be resolved. */ static int resolveAttachExpr(NameContext *pName, Expr *pExpr) { int rc = SQLITE_OK; if( pExpr ){ if( pExpr->op!=TK_ID ){ rc = sqlite3ResolveExprNames(pName, pExpr); }else{ pExpr->op = TK_STRING; } } return rc; } /* ** Return true if zName points to a name that may be used to refer to ** database iDb attached to handle db. */ int sqlite3DbIsNamed(sqlite3 *db, int iDb, const char *zName){ return ( sqlite3StrICmp(db->aDb[iDb].zDbSName, zName)==0 || (iDb==0 && sqlite3StrICmp("main", zName)==0) ); } /* ** 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. ** ** If the db->init.reopenMemdb flags is set, then instead of attaching a ** new database, close the database on db->init.iDb and reopen it as an ** empty MemDB. */ 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; /* New array of Db pointers */ Db *pNew = 0; /* Db object for the newly attached database */ 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 = ""; #ifndef SQLITE_OMIT_DESERIALIZE # define REOPEN_AS_MEMDB(db) (db->init.reopenMemdb) #else # define REOPEN_AS_MEMDB(db) (0) #endif if( REOPEN_AS_MEMDB(db) ){ /* This is not a real ATTACH. Instead, this routine is being called ** from sqlite3_deserialize() to close database db->init.iDb and ** reopen it as a MemDB */ Btree *pNewBt = 0; pVfs = sqlite3_vfs_find("memdb"); if( pVfs==0 ) return; rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB); if( rc==SQLITE_OK ){ Schema *pNewSchema = sqlite3SchemaGet(db, pNewBt); if( pNewSchema ){ /* Both the Btree and the new Schema were allocated successfully. ** Close the old db and update the aDb[] slot with the new memdb ** values. */ pNew = &db->aDb[db->init.iDb]; if( ALWAYS(pNew->pBt) ) sqlite3BtreeClose(pNew->pBt); pNew->pBt = pNewBt; pNew->pSchema = pNewSchema; }else{ sqlite3BtreeClose(pNewBt); rc = SQLITE_NOMEM; } } if( rc ) goto attach_error; }else{ /* This is a real ATTACH ** ** 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; } for(i=0; inDb; i++){ assert( zName ); if( sqlite3DbIsNamed(db, i, zName) ){ 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 = sqlite3DbMallocRawNN(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; pNew = &db->aDb[db->nDb]; memset(pNew, 0, sizeof(*pNew)); /* 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 ) sqlite3OomFault(db); sqlite3_result_error(context, zErr, -1); sqlite3_free(zErr); return; } assert( pVfs ); flags |= SQLITE_OPEN_MAIN_DB; rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags); db->nDb++; pNew->zDbSName = sqlite3DbStrDup(db, zName); } db->noSharedCache = 0; if( rc==SQLITE_CONSTRAINT ){ rc = SQLITE_ERROR; zErrDyn = sqlite3MPrintf(db, "database is already attached"); }else if( rc==SQLITE_OK ){ Pager *pPager; pNew->pSchema = sqlite3SchemaGet(db, pNew->pBt); if( !pNew->pSchema ){ rc = SQLITE_NOMEM_BKPT; }else if( pNew->pSchema->file_format && pNew->pSchema->enc!=ENC(db) ){ zErrDyn = sqlite3MPrintf(db, "attached databases must use the same text encoding as main database"); rc = SQLITE_ERROR; } sqlite3BtreeEnter(pNew->pBt); pPager = sqlite3BtreePager(pNew->pBt); sqlite3PagerLockingMode(pPager, db->dfltLockMode); sqlite3BtreeSecureDelete(pNew->pBt, sqlite3BtreeSecureDelete(db->aDb[0].pBt,-1) ); #ifndef SQLITE_OMIT_PAGER_PRAGMAS sqlite3BtreeSetPagerFlags(pNew->pBt, PAGER_SYNCHRONOUS_FULL | (db->flags & PAGER_FLAGS_MASK)); #endif sqlite3BtreeLeave(pNew->pBt); } pNew->safety_level = SQLITE_DEFAULT_SYNCHRONOUS+1; if( rc==SQLITE_OK && pNew->zDbSName==0 ){ rc = SQLITE_NOMEM_BKPT; } sqlite3_free_filename( zPath ); /* 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); db->init.iDb = 0; db->mDbFlags &= ~(DBFLAG_SchemaKnownOk); if( !REOPEN_AS_MEMDB(db) ){ rc = sqlite3Init(db, &zErrDyn); } sqlite3BtreeLeaveAll(db); assert( zErrDyn==0 || rc!=SQLITE_OK ); } if( rc ){ if( ALWAYS(!REOPEN_AS_MEMDB(db)) ){ 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 ){ sqlite3OomFault(db); 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); } /* ** An SQL user-function registered to do the work of an DETACH statement. The ** three arguments to the function come directly from a detach statement: ** ** DETACH DATABASE x ** ** SELECT sqlite_detach(x) */ static void detachFunc( sqlite3_context *context, int NotUsed, sqlite3_value **argv ){ const char *zName = (const char *)sqlite3_value_text(argv[0]); sqlite3 *db = sqlite3_context_db_handle(context); int i; Db *pDb = 0; HashElem *pEntry; char zErr[128]; UNUSED_PARAMETER(NotUsed); if( zName==0 ) zName = ""; for(i=0; inDb; i++){ pDb = &db->aDb[i]; if( pDb->pBt==0 ) continue; if( sqlite3DbIsNamed(db, i, zName) ) break; } if( i>=db->nDb ){ sqlite3_snprintf(sizeof(zErr),zErr, "no such database: %s", zName); goto detach_error; } if( i<2 ){ sqlite3_snprintf(sizeof(zErr),zErr, "cannot detach database %s", zName); goto detach_error; } if( sqlite3BtreeTxnState(pDb->pBt)!=SQLITE_TXN_NONE || sqlite3BtreeIsInBackup(pDb->pBt) ){ sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName); goto detach_error; } /* If any TEMP triggers reference the schema being detached, move those ** triggers to reference the TEMP schema itself. */ assert( db->aDb[1].pSchema ); pEntry = sqliteHashFirst(&db->aDb[1].pSchema->trigHash); while( pEntry ){ Trigger *pTrig = (Trigger*)sqliteHashData(pEntry); if( pTrig->pTabSchema==pDb->pSchema ){ pTrig->pTabSchema = pTrig->pSchema; } pEntry = sqliteHashNext(pEntry); } sqlite3BtreeClose(pDb->pBt); pDb->pBt = 0; pDb->pSchema = 0; sqlite3CollapseDatabaseArray(db); return; detach_error: sqlite3_result_error(context, zErr, -1); } /* ** This procedure generates VDBE code for a single invocation of either the ** sqlite_detach() or sqlite_attach() SQL user functions. */ static void codeAttach( Parse *pParse, /* The parser context */ int type, /* Either SQLITE_ATTACH or SQLITE_DETACH */ FuncDef const *pFunc,/* FuncDef wrapper for detachFunc() or attachFunc() */ Expr *pAuthArg, /* Expression to pass to authorization callback */ Expr *pFilename, /* Name of database file */ Expr *pDbname, /* Name of the database to use internally */ Expr *pKey /* Database key for encryption extension */ ){ int rc; NameContext sName; Vdbe *v; sqlite3* db = pParse->db; int regArgs; if( SQLITE_OK!=sqlite3ReadSchema(pParse) ) goto attach_end; if( pParse->nErr ) goto attach_end; memset(&sName, 0, sizeof(NameContext)); sName.pParse = pParse; if( SQLITE_OK!=resolveAttachExpr(&sName, pFilename) || SQLITE_OK!=resolveAttachExpr(&sName, pDbname) || SQLITE_OK!=resolveAttachExpr(&sName, pKey) ){ goto attach_end; } #ifndef SQLITE_OMIT_AUTHORIZATION if( ALWAYS(pAuthArg) ){ char *zAuthArg; if( pAuthArg->op==TK_STRING ){ assert( !ExprHasProperty(pAuthArg, EP_IntValue) ); zAuthArg = pAuthArg->u.zToken; }else{ zAuthArg = 0; } rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0); if(rc!=SQLITE_OK ){ goto attach_end; } } #endif /* SQLITE_OMIT_AUTHORIZATION */ v = sqlite3GetVdbe(pParse); regArgs = sqlite3GetTempRange(pParse, 4); sqlite3ExprCode(pParse, pFilename, regArgs); sqlite3ExprCode(pParse, pDbname, regArgs+1); sqlite3ExprCode(pParse, pKey, regArgs+2); assert( v || db->mallocFailed ); if( v ){ sqlite3VdbeAddFunctionCall(pParse, 0, regArgs+3-pFunc->nArg, regArgs+3, pFunc->nArg, pFunc, 0); /* Code an OP_Expire. For an ATTACH statement, set P1 to true (expire this ** statement only). For DETACH, set it to false (expire all existing ** statements). */ sqlite3VdbeAddOp1(v, OP_Expire, (type==SQLITE_ATTACH)); } attach_end: sqlite3ExprDelete(db, pFilename); sqlite3ExprDelete(db, pDbname); sqlite3ExprDelete(db, pKey); } /* ** Called by the parser to compile a DETACH statement. ** ** DETACH pDbname */ void sqlite3Detach(Parse *pParse, Expr *pDbname){ static const FuncDef detach_func = { 1, /* nArg */ SQLITE_UTF8, /* funcFlags */ 0, /* pUserData */ 0, /* pNext */ detachFunc, /* xSFunc */ 0, /* xFinalize */ 0, 0, /* xValue, xInverse */ "sqlite_detach", /* zName */ {0} }; codeAttach(pParse, SQLITE_DETACH, &detach_func, pDbname, 0, 0, pDbname); } /* ** Called by the parser to compile an ATTACH statement. ** ** ATTACH p AS pDbname KEY pKey */ void sqlite3Attach(Parse *pParse, Expr *p, Expr *pDbname, Expr *pKey){ static const FuncDef attach_func = { 3, /* nArg */ SQLITE_UTF8, /* funcFlags */ 0, /* pUserData */ 0, /* pNext */ attachFunc, /* xSFunc */ 0, /* xFinalize */ 0, 0, /* xValue, xInverse */ "sqlite_attach", /* zName */ {0} }; codeAttach(pParse, SQLITE_ATTACH, &attach_func, p, p, pDbname, pKey); } #endif /* SQLITE_OMIT_ATTACH */ /* ** Expression callback used by sqlite3FixAAAA() routines. */ static int fixExprCb(Walker *p, Expr *pExpr){ DbFixer *pFix = p->u.pFix; if( !pFix->bTemp ) ExprSetProperty(pExpr, EP_FromDDL); if( pExpr->op==TK_VARIABLE ){ if( pFix->pParse->db->init.busy ){ pExpr->op = TK_NULL; }else{ sqlite3ErrorMsg(pFix->pParse, "%s cannot use variables", pFix->zType); return WRC_Abort; } } return WRC_Continue; } /* ** Select callback used by sqlite3FixAAAA() routines. */ static int fixSelectCb(Walker *p, Select *pSelect){ DbFixer *pFix = p->u.pFix; int i; SrcItem *pItem; sqlite3 *db = pFix->pParse->db; int iDb = sqlite3FindDbName(db, pFix->zDb); SrcList *pList = pSelect->pSrc; if( NEVER(pList==0) ) return WRC_Continue; for(i=0, pItem=pList->a; inSrc; i++, pItem++){ if( pFix->bTemp==0 && pItem->fg.isSubquery==0 ){ if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){ if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){ sqlite3ErrorMsg(pFix->pParse, "%s %T cannot reference objects in database %s", pFix->zType, pFix->pName, pItem->u4.zDatabase); return WRC_Abort; } sqlite3DbFree(db, pItem->u4.zDatabase); pItem->fg.notCte = 1; pItem->fg.hadSchema = 1; } pItem->u4.pSchema = pFix->pSchema; pItem->fg.fromDDL = 1; pItem->fg.fixedSchema = 1; } #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) if( pList->a[i].fg.isUsing==0 && sqlite3WalkExpr(&pFix->w, pList->a[i].u3.pOn) ){ return WRC_Abort; } #endif } if( pSelect->pWith ){ for(i=0; ipWith->nCte; i++){ if( sqlite3WalkSelect(p, pSelect->pWith->a[i].pSelect) ){ return WRC_Abort; } } } return WRC_Continue; } /* ** Initialize a DbFixer structure. This routine must be called prior ** to passing the structure to one of the sqliteFixAAAA() routines below. */ void sqlite3FixInit( DbFixer *pFix, /* The fixer to be initialized */ Parse *pParse, /* Error messages will be written here */ int iDb, /* This is the database that must be used */ const char *zType, /* "view", "trigger", or "index" */ const Token *pName /* Name of the view, trigger, or index */ ){ sqlite3 *db = pParse->db; assert( db->nDb>iDb ); pFix->pParse = pParse; pFix->zDb = db->aDb[iDb].zDbSName; pFix->pSchema = db->aDb[iDb].pSchema; pFix->zType = zType; pFix->pName = pName; pFix->bTemp = (iDb==1); pFix->w.pParse = pParse; pFix->w.xExprCallback = fixExprCb; pFix->w.xSelectCallback = fixSelectCb; pFix->w.xSelectCallback2 = sqlite3WalkWinDefnDummyCallback; pFix->w.walkerDepth = 0; pFix->w.eCode = 0; pFix->w.u.pFix = pFix; } /* ** The following set of routines walk through the parse tree and assign ** a specific database to all table references where the database name ** was left unspecified in the original SQL statement. The pFix structure ** must have been initialized by a prior call to sqlite3FixInit(). ** ** These routines are used to make sure that an index, trigger, or ** view in one database does not refer to objects in a different database. ** (Exception: indices, triggers, and views in the TEMP database are ** allowed to refer to anything.) If a reference is explicitly made ** to an object in a different database, an error message is added to ** pParse->zErrMsg and these routines return non-zero. If everything ** checks out, these routines return 0. */ int sqlite3FixSrcList( DbFixer *pFix, /* Context of the fixation */ SrcList *pList /* The Source list to check and modify */ ){ int res = 0; if( pList ){ Select s; memset(&s, 0, sizeof(s)); s.pSrc = pList; res = sqlite3WalkSelect(&pFix->w, &s); } return res; } #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) int sqlite3FixSelect( DbFixer *pFix, /* Context of the fixation */ Select *pSelect /* The SELECT statement to be fixed to one database */ ){ return sqlite3WalkSelect(&pFix->w, pSelect); } int sqlite3FixExpr( DbFixer *pFix, /* Context of the fixation */ Expr *pExpr /* The expression to be fixed to one database */ ){ return sqlite3WalkExpr(&pFix->w, pExpr); } #endif #ifndef SQLITE_OMIT_TRIGGER int sqlite3FixTriggerStep( DbFixer *pFix, /* Context of the fixation */ TriggerStep *pStep /* The trigger step be fixed to one database */ ){ while( pStep ){ if( sqlite3WalkSelect(&pFix->w, pStep->pSelect) || sqlite3WalkExpr(&pFix->w, pStep->pWhere) || sqlite3WalkExprList(&pFix->w, pStep->pExprList) || sqlite3FixSrcList(pFix, pStep->pFrom) ){ return 1; } #ifndef SQLITE_OMIT_UPSERT { Upsert *pUp; for(pUp=pStep->pUpsert; pUp; pUp=pUp->pNextUpsert){ if( sqlite3WalkExprList(&pFix->w, pUp->pUpsertTarget) || sqlite3WalkExpr(&pFix->w, pUp->pUpsertTargetWhere) || sqlite3WalkExprList(&pFix->w, pUp->pUpsertSet) || sqlite3WalkExpr(&pFix->w, pUp->pUpsertWhere) ){ return 1; } } } #endif pStep = pStep->pNext; } return 0; } #endif