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DEFINITIONS
This source file includes following definitions.
- resolveAttachExpr
- attachFunc
- detachFunc
- codeAttach
- sqlite3Detach
- sqlite3Attach
- sqlite3AttachFunctions
- sqlite3FixInit
- sqlite3FixSrcList
- sqlite3FixSelect
- sqlite3FixExpr
- sqlite3FixExprList
- sqlite3FixTriggerStep
/*
** 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.
**
** $Id$
*/
#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 = sqlite3ExprResolveNames(pName, pExpr);
}else{
pExpr->op = TK_STRING;
}
}
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 argc,
sqlite3_value **argv
){
int i;
int rc = 0;
sqlite3 *db = sqlite3_user_data(context);
const char *zName;
const char *zFile;
Db *aNew;
char zErr[128];
char *zErrDyn = 0;
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>=MAX_ATTACHED+2 ){
sqlite3_snprintf(
sizeof(zErr), zErr, "too many attached databases - max %d", MAX_ATTACHED
);
goto attach_error;
}
if( !db->autoCommit ){
strcpy(zErr, "cannot ATTACH database within transaction");
goto attach_error;
}
for(i=0; i<db->nDb; i++){
char *z = db->aDb[i].zName;
if( z && zName && sqlite3StrICmp(z, zName)==0 ){
sqlite3_snprintf(sizeof(zErr), zErr, "database %s is already in use", zName);
goto attach_error;
}
}
/* Allocate the new entry in the db->aDb[] array and initialise the schema
** hash tables.
*/
if( db->aDb==db->aDbStatic ){
aNew = sqliteMalloc( sizeof(db->aDb[0])*3 );
if( aNew==0 ){
return;
}
memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
}else{
aNew = sqliteRealloc(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 initialised.
*/
rc = sqlite3BtreeFactory(db, zFile, 0, MAX_PAGES, &aNew->pBt);
if( rc==SQLITE_OK ){
aNew->pSchema = sqlite3SchemaGet(aNew->pBt);
if( !aNew->pSchema ){
rc = SQLITE_NOMEM;
}else if( aNew->pSchema->file_format && aNew->pSchema->enc!=ENC(db) ){
strcpy(zErr,
"attached databases must use the same text encoding as main database");
goto attach_error;
}
sqlite3PagerLockingMode(sqlite3BtreePager(aNew->pBt), db->dfltLockMode);
}
aNew->zName = sqliteStrDup(zName);
aNew->safety_level = 3;
#if SQLITE_HAS_CODEC
{
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 = sqliteStrDup("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]);
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);
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 ){
sqlite3SafetyOn(db);
rc = sqlite3Init(db, &zErrDyn);
sqlite3SafetyOff(db);
}
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;
}
sqlite3ResetInternalSchema(db, 0);
db->nDb = iDb;
if( rc==SQLITE_NOMEM ){
sqlite3FailedMalloc();
sqlite3_snprintf(sizeof(zErr),zErr, "out of memory");
}else{
sqlite3_snprintf(sizeof(zErr),zErr, "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);
sqliteFree(zErrDyn);
}else{
zErr[sizeof(zErr)-1] = 0;
sqlite3_result_error(context, zErr, -1);
}
}
/*
** 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 argc,
sqlite3_value **argv
){
const char *zName = (const char *)sqlite3_value_text(argv[0]);
sqlite3 *db = sqlite3_user_data(context);
int i;
Db *pDb = 0;
char zErr[128];
if( zName==0 ) zName = "";
for(i=0; i<db->nDb; i++){
pDb = &db->aDb[i];
if( pDb->pBt==0 ) continue;
if( sqlite3StrICmp(pDb->zName, zName)==0 ) 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( !db->autoCommit ){
strcpy(zErr, "cannot DETACH database within transaction");
goto detach_error;
}
if( sqlite3BtreeIsInReadTrans(pDb->pBt) ){
sqlite3_snprintf(sizeof(zErr),zErr, "database %s is locked", zName);
goto detach_error;
}
sqlite3BtreeClose(pDb->pBt);
pDb->pBt = 0;
pDb->pSchema = 0;
sqlite3ResetInternalSchema(db, 0);
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 */
const char *zFunc, /* Either "sqlite_attach" or "sqlite_detach */
int nFunc, /* Number of args to pass to zFunc */
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;
FuncDef *pFunc;
sqlite3* db = pParse->db;
#ifndef SQLITE_OMIT_AUTHORIZATION
assert( sqlite3MallocFailed() || pAuthArg );
if( pAuthArg ){
char *zAuthArg = sqlite3NameFromToken(&pAuthArg->span);
if( !zAuthArg ){
goto attach_end;
}
rc = sqlite3AuthCheck(pParse, type, zAuthArg, 0, 0);
sqliteFree(zAuthArg);
if(rc!=SQLITE_OK ){
goto attach_end;
}
}
#endif /* SQLITE_OMIT_AUTHORIZATION */
memset(&sName, 0, sizeof(NameContext));
sName.pParse = pParse;
if(
SQLITE_OK!=(rc = resolveAttachExpr(&sName, pFilename)) ||
SQLITE_OK!=(rc = resolveAttachExpr(&sName, pDbname)) ||
SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
){
pParse->nErr++;
goto attach_end;
}
v = sqlite3GetVdbe(pParse);
sqlite3ExprCode(pParse, pFilename);
sqlite3ExprCode(pParse, pDbname);
sqlite3ExprCode(pParse, pKey);
assert( v || sqlite3MallocFailed() );
if( v ){
sqlite3VdbeAddOp(v, OP_Function, 0, nFunc);
pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
sqlite3VdbeChangeP3(v, -1, (char *)pFunc, P3_FUNCDEF);
/* 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).
*/
sqlite3VdbeAddOp(v, OP_Expire, (type==SQLITE_ATTACH), 0);
}
attach_end:
sqlite3ExprDelete(pFilename);
sqlite3ExprDelete(pDbname);
sqlite3ExprDelete(pKey);
}
/*
** Called by the parser to compile a DETACH statement.
**
** DETACH pDbname
*/
void sqlite3Detach(Parse *pParse, Expr *pDbname){
codeAttach(pParse, SQLITE_DETACH, "sqlite_detach", 1, 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){
codeAttach(pParse, SQLITE_ATTACH, "sqlite_attach", 3, p, p, pDbname, pKey);
}
#endif /* SQLITE_OMIT_ATTACH */
/*
** Register the functions sqlite_attach and sqlite_detach.
*/
void sqlite3AttachFunctions(sqlite3 *db){
#ifndef SQLITE_OMIT_ATTACH
static const int enc = SQLITE_UTF8;
sqlite3CreateFunc(db, "sqlite_attach", 3, enc, db, attachFunc, 0, 0);
sqlite3CreateFunc(db, "sqlite_detach", 1, enc, db, detachFunc, 0, 0);
#endif
}
/*
** Initialize a DbFixer structure. This routine must be called prior
** to passing the structure to one of the sqliteFixAAAA() routines below.
**
** The return value indicates whether or not fixation is required. TRUE
** means we do need to fix the database references, FALSE means we do not.
*/
int 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;
if( iDb<0 || iDb==1 ) return 0;
db = pParse->db;
assert( db->nDb>iDb );
pFix->pParse = pParse;
pFix->zDb = db->aDb[iDb].zName;
pFix->zType = zType;
pFix->pName = pName;
return 1;
}
/*
** 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 i;
const char *zDb;
struct SrcList_item *pItem;
if( pList==0 ) return 0;
zDb = pFix->zDb;
for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
if( pItem->zDatabase==0 ){
pItem->zDatabase = sqliteStrDup(zDb);
}else if( sqlite3StrICmp(pItem->zDatabase,zDb)!=0 ){
sqlite3ErrorMsg(pFix->pParse,
"%s %T cannot reference objects in database %s",
pFix->zType, pFix->pName, pItem->zDatabase);
return 1;
}
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
if( sqlite3FixSelect(pFix, pItem->pSelect) ) return 1;
if( sqlite3FixExpr(pFix, pItem->pOn) ) return 1;
#endif
}
return 0;
}
#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 */
){
while( pSelect ){
if( sqlite3FixExprList(pFix, pSelect->pEList) ){
return 1;
}
if( sqlite3FixSrcList(pFix, pSelect->pSrc) ){
return 1;
}
if( sqlite3FixExpr(pFix, pSelect->pWhere) ){
return 1;
}
if( sqlite3FixExpr(pFix, pSelect->pHaving) ){
return 1;
}
pSelect = pSelect->pPrior;
}
return 0;
}
int sqlite3FixExpr(
DbFixer *pFix, /* Context of the fixation */
Expr *pExpr /* The expression to be fixed to one database */
){
while( pExpr ){
if( sqlite3FixSelect(pFix, pExpr->pSelect) ){
return 1;
}
if( sqlite3FixExprList(pFix, pExpr->pList) ){
return 1;
}
if( sqlite3FixExpr(pFix, pExpr->pRight) ){
return 1;
}
pExpr = pExpr->pLeft;
}
return 0;
}
int sqlite3FixExprList(
DbFixer *pFix, /* Context of the fixation */
ExprList *pList /* The expression to be fixed to one database */
){
int i;
struct ExprList_item *pItem;
if( pList==0 ) return 0;
for(i=0, pItem=pList->a; i<pList->nExpr; i++, pItem++){
if( sqlite3FixExpr(pFix, pItem->pExpr) ){
return 1;
}
}
return 0;
}
#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( sqlite3FixSelect(pFix, pStep->pSelect) ){
return 1;
}
if( sqlite3FixExpr(pFix, pStep->pWhere) ){
return 1;
}
if( sqlite3FixExprList(pFix, pStep->pExprList) ){
return 1;
}
pStep = pStep->pNext;
}
return 0;
}
#endif