sqlcipher/src/prepare.c at sqlite-release · sqlcipher/sqlcipher · GitHub

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** 2005 May 25

** 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 the implementation of the sqlite3_prepare()

** interface, and routines that contribute to loading the database schema

** from disk.

#include "sqliteInt.h"

** Fill the InitData structure with an error message that indicates

** that the database is corrupt.

static void corruptSchema(

InitData *pData, /* Initialization context */

char **azObj, /* Type and name of object being parsed */

const char *zExtra /* Error information */

){

sqlite3 *db = pData->db;

if( db->mallocFailed ){

pData->rc = SQLITE_NOMEM_BKPT;

}else if( pData->pzErrMsg[0]!=0 ){

/* A error message has already been generated. Do not overwrite it */

}else if( pData->mInitFlags & (INITFLAG_AlterMask) ){

static const char *azAlterType[] = {

"rename",

"drop column",

"add column",

"drop constraint"

};

*pData->pzErrMsg = sqlite3MPrintf(db,

"error in %s %s after %s: %s", azObj[0], azObj[1],

azAlterType[(pData->mInitFlags&INITFLAG_AlterMask)-1],

zExtra

);

pData->rc = SQLITE_ERROR;

}else if( db->flags & SQLITE_WriteSchema ){

pData->rc = SQLITE_CORRUPT_BKPT;

}else{

char *z;

const char *zObj = azObj[1] ? azObj[1] : "?";

z = sqlite3MPrintf(db, "malformed database schema (%s)", zObj);

if( zExtra && zExtra[0] ) z = sqlite3MPrintf(db, "%z - %s", z, zExtra);

*pData->pzErrMsg = z;

pData->rc = SQLITE_CORRUPT_BKPT;

}

** Check to see if any sibling index (another index on the same table)

** of pIndex has the same root page number, and if it does, return true.

** This would indicate a corrupt schema.

int sqlite3IndexHasDuplicateRootPage(Index *pIndex){

Index *p;

for(p=pIndex->pTable->pIndex; p; p=p->pNext){

if( p->tnum==pIndex->tnum && p!=pIndex ) return 1;

}

return 0;

}

/* forward declaration */

static int sqlite3Prepare(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

u32 prepFlags, /* Zero or more SQLITE_PREPARE_* flags */

Vdbe *pReprepare, /* VM being reprepared */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

);

** This is the callback routine for the code that initializes the

** database. See sqlite3Init() below for additional information.

** This routine is also called from the OP_ParseSchema opcode of the VDBE.

** Each callback contains the following information:

** argv[0] = type of object: "table", "index", "trigger", or "view".

** argv[1] = name of thing being created

** argv[2] = associated table if an index or trigger

** argv[3] = root page number for table or index. 0 for trigger or view.

** argv[4] = SQL text for the CREATE statement.

int sqlite3InitCallback(void *pInit, int argc, char **argv, char **NotUsed){

InitData *pData = (InitData*)pInit;

sqlite3 *db = pData->db;

int iDb = pData->iDb;

assert( argc==5 );

UNUSED_PARAMETER2(NotUsed, argc);

assert( sqlite3_mutex_held(db->mutex) );

db->mDbFlags |= DBFLAG_EncodingFixed;

if( argv==0 ) return 0; /* Might happen if EMPTY_RESULT_CALLBACKS are on */

pData->nInitRow++;

if( db->mallocFailed ){

corruptSchema(pData, argv, 0);

return 1;

}

assert( iDb>=0 && iDb<db->nDb );

if( argv[3]==0 ){

corruptSchema(pData, argv, 0);

}else if( argv[4]

&& 'c'==sqlite3UpperToLower[(unsigned char)argv[4][0]]

&& 'r'==sqlite3UpperToLower[(unsigned char)argv[4][1]] ){

/* Call the parser to process a CREATE TABLE, INDEX or VIEW.

** But because db->init.busy is set to 1, no VDBE code is generated

** or executed. All the parser does is build the internal data

** structures that describe the table, index, or view.

** No other valid SQL statement, other than the variable CREATE statements,

** can begin with the letters "C" and "R". Thus, it is not possible run

** any other kind of statement while parsing the schema, even a corrupt

** schema.

int rc;

u8 saved_iDb = db->init.iDb;

sqlite3_stmt *pStmt;

TESTONLY(int rcp); /* Return code from sqlite3_prepare() */

assert( db->init.busy );

db->init.iDb = iDb;

if( sqlite3GetUInt32(argv[3], &db->init.newTnum)==0

|| (db->init.newTnum>pData->mxPage && pData->mxPage>0)

){

if( sqlite3Config.bExtraSchemaChecks ){

corruptSchema(pData, argv, "invalid rootpage");

}

db->init.orphanTrigger = 0;

db->init.azInit = (const char**)argv;

pStmt = 0;

TESTONLY(rcp = ) sqlite3Prepare(db, argv[4], -1, 0, 0, &pStmt, 0);

rc = db->errCode;

assert( (rc&0xFF)==(rcp&0xFF) );

db->init.iDb = saved_iDb;

/* assert( saved_iDb==0 || (db->mDbFlags & DBFLAG_Vacuum)!=0 ); */

if( SQLITE_OK!=rc ){

if( db->init.orphanTrigger ){

assert( iDb==1 );

}else{

if( rc > pData->rc ) pData->rc = rc;

if( rc==SQLITE_NOMEM ){

sqlite3OomFault(db);

}else if( rc!=SQLITE_INTERRUPT && (rc&0xFF)!=SQLITE_LOCKED ){

corruptSchema(pData, argv, sqlite3_errmsg(db));

}

db->init.azInit = sqlite3StdType; /* Any array of string ptrs will do */

sqlite3_finalize(pStmt);

}else if( argv[1]==0 || (argv[4]!=0 && argv[4][0]!=0) ){

corruptSchema(pData, argv, 0);

}else{

/* If the SQL column is blank it means this is an index that

** was created to be the PRIMARY KEY or to fulfill a UNIQUE

** constraint for a CREATE TABLE. The index should have already

** been created when we processed the CREATE TABLE. All we have

** to do here is record the root page number for that index.

Index *pIndex;

pIndex = sqlite3FindIndex(db, argv[1], db->aDb[iDb].zDbSName);

if( pIndex==0 ){

corruptSchema(pData, argv, "orphan index");

}else

if( sqlite3GetUInt32(argv[3],&pIndex->tnum)==0

|| pIndex->tnum<2

|| pIndex->tnum>pData->mxPage

|| sqlite3IndexHasDuplicateRootPage(pIndex)

){

if( sqlite3Config.bExtraSchemaChecks ){

corruptSchema(pData, argv, "invalid rootpage");

}

return 0;

}

** Attempt to read the database schema and initialize internal

** data structures for a single database file. The index of the

** database file is given by iDb. iDb==0 is used for the main

** database. iDb==1 should never be used. iDb>=2 is used for

** auxiliary databases. Return one of the SQLITE_ error codes to

** indicate success or failure.

int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){

int rc;

int i;

#ifndef SQLITE_OMIT_DEPRECATED

int size;

#endif

Db *pDb;

char const *azArg[6];

int meta[5];

InitData initData;

const char *zSchemaTabName;

int openedTransaction = 0;

int mask = ((db->mDbFlags & DBFLAG_EncodingFixed) | ~DBFLAG_EncodingFixed);

assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );

assert( iDb>=0 && iDb<db->nDb );

assert( db->aDb[iDb].pSchema );

assert( sqlite3_mutex_held(db->mutex) );

assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

db->init.busy = 1;

/* Construct the in-memory representation schema tables (sqlite_schema or

** sqlite_temp_schema) by invoking the parser directly. The appropriate

** table name will be inserted automatically by the parser so we can just

** use the abbreviation "x" here. The parser will also automatically tag

** the schema table as read-only. */

azArg[0] = "table";

azArg[1] = zSchemaTabName = SCHEMA_TABLE(iDb);

azArg[2] = azArg[1];

azArg[3] = "1";

azArg[4] = "CREATE TABLE x(type text,name text,tbl_name text,"

"rootpage int,sql text)";

azArg[5] = 0;

initData.db = db;

initData.iDb = iDb;

initData.rc = SQLITE_OK;

initData.pzErrMsg = pzErrMsg;

initData.mInitFlags = mFlags;

initData.nInitRow = 0;

initData.mxPage = 0;

sqlite3InitCallback(&initData, 5, (char **)azArg, 0);

db->mDbFlags &= mask;

if( initData.rc ){

rc = initData.rc;

goto error_out;

}

/* Create a cursor to hold the database open

pDb = &db->aDb[iDb];

if( pDb->pBt==0 ){

assert( iDb==1 );

DbSetProperty(db, 1, DB_SchemaLoaded);

rc = SQLITE_OK;

goto error_out;

}

/* If there is not already a read-only (or read-write) transaction opened

** on the b-tree database, open one now. If a transaction is opened, it

** will be closed before this function returns. */

sqlite3BtreeEnter(pDb->pBt);

if( sqlite3BtreeTxnState(pDb->pBt)==SQLITE_TXN_NONE ){

rc = sqlite3BtreeBeginTrans(pDb->pBt, 0, 0);

if( rc!=SQLITE_OK ){

sqlite3SetString(pzErrMsg, db, sqlite3ErrStr(rc));

goto initone_error_out;

}

openedTransaction = 1;

}

/* Get the database meta information.

** Meta values are as follows:

** meta[0] Schema cookie. Changes with each schema change.

** meta[1] File format of schema layer.

** meta[2] Size of the page cache.

** meta[3] Largest rootpage (auto/incr_vacuum mode)

** meta[4] Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE

** meta[5] User version

** meta[6] Incremental vacuum mode

** meta[7] unused

** meta[8] unused

** meta[9] unused

** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to

** the possible values of meta[4].

for(i=0; i<ArraySize(meta); i++){

sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);

}

if( (db->flags & SQLITE_ResetDatabase)!=0 ){

memset(meta, 0, sizeof(meta));

}

pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];

/* If opening a non-empty database, check the text encoding. For the

** main database, set sqlite3.enc to the encoding of the main database.

** For an attached db, it is an error if the encoding is not the same

** as sqlite3.enc.

if( meta[BTREE_TEXT_ENCODING-1] ){ /* text encoding */

if( iDb==0 && (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){

u8 encoding;

#ifndef SQLITE_OMIT_UTF16

/* If opening the main database, set ENC(db). */

encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;

if( encoding==0 ) encoding = SQLITE_UTF8;

#else

encoding = SQLITE_UTF8;

#endif

sqlite3SetTextEncoding(db, encoding);

}else{

/* If opening an attached database, the encoding much match ENC(db) */

if( (meta[BTREE_TEXT_ENCODING-1] & 3)!=ENC(db) ){

sqlite3SetString(pzErrMsg, db, "attached databases must use the same"

" text encoding as main database");

rc = SQLITE_ERROR;

goto initone_error_out;

}

pDb->pSchema->enc = ENC(db);

if( pDb->pSchema->cache_size==0 ){

#ifndef SQLITE_OMIT_DEPRECATED

size = sqlite3AbsInt32(meta[BTREE_DEFAULT_CACHE_SIZE-1]);

if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }

pDb->pSchema->cache_size = size;

#else

pDb->pSchema->cache_size = SQLITE_DEFAULT_CACHE_SIZE;

#endif

sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);

}

** file_format==1 Version 3.0.0.

** file_format==2 Version 3.1.3. // ALTER TABLE ADD COLUMN

** file_format==3 Version 3.1.4. // ditto but with non-NULL defaults

** file_format==4 Version 3.3.0. // DESC indices. Boolean constants

pDb->pSchema->file_format = (u8)meta[BTREE_FILE_FORMAT-1];

if( pDb->pSchema->file_format==0 ){

pDb->pSchema->file_format = 1;

}

if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){

sqlite3SetString(pzErrMsg, db, "unsupported file format");

rc = SQLITE_ERROR;

goto initone_error_out;

}

/* Ticket #2804: When we open a database in the newer file format,

** clear the legacy_file_format pragma flag so that a VACUUM will

** not downgrade the database and thus invalidate any descending

** indices that the user might have created.

if( iDb==0 && meta[BTREE_FILE_FORMAT-1]>=4 ){

db->flags &= ~(u64)SQLITE_LegacyFileFmt;

}

/* Read the schema information out of the schema tables

assert( db->init.busy );

initData.mxPage = sqlite3BtreeLastPage(pDb->pBt);

{

char *zSql;

zSql = sqlite3MPrintf(db,

"SELECT*FROM\"%w\".%s ORDER BY rowid",

db->aDb[iDb].zDbSName, zSchemaTabName);

#ifndef SQLITE_OMIT_AUTHORIZATION

{

sqlite3_xauth xAuth;

xAuth = db->xAuth;

db->xAuth = 0;

#endif

rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);

#ifndef SQLITE_OMIT_AUTHORIZATION

db->xAuth = xAuth;

}

#endif

if( rc==SQLITE_OK ) rc = initData.rc;

sqlite3DbFree(db, zSql);

#ifndef SQLITE_OMIT_ANALYZE

if( rc==SQLITE_OK ){

sqlite3AnalysisLoad(db, iDb);

}

#endif

}

assert( pDb == &(db->aDb[iDb]) );

if( db->mallocFailed ){

rc = SQLITE_NOMEM_BKPT;

sqlite3ResetAllSchemasOfConnection(db);

pDb = &db->aDb[iDb];

}else

if( rc==SQLITE_OK || ((db->flags&SQLITE_NoSchemaError) && rc!=SQLITE_NOMEM)){

/* Hack: If the SQLITE_NoSchemaError flag is set, then consider

** the schema loaded, even if errors (other than OOM) occurred. In

** this situation the current sqlite3_prepare() operation will fail,

** but the following one will attempt to compile the supplied statement

** against whatever subset of the schema was loaded before the error

** occurred.

** The primary purpose of this is to allow access to the sqlite_schema

** table even when its contents have been corrupted.

DbSetProperty(db, iDb, DB_SchemaLoaded);

rc = SQLITE_OK;

}

/* Jump here for an error that occurs after successfully allocating

** curMain and calling sqlite3BtreeEnter(). For an error that occurs

** before that point, jump to error_out.

initone_error_out:

if( openedTransaction ){

sqlite3BtreeCommit(pDb->pBt);

}

sqlite3BtreeLeave(pDb->pBt);

error_out:

if( rc ){

if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){

sqlite3OomFault(db);

}

sqlite3ResetOneSchema(db, iDb);

}

db->init.busy = 0;

return rc;

}

** Initialize all database files - the main database file, the file

** used to store temporary tables, and any additional database files

** created using ATTACH statements. Return a success code. If an

** error occurs, write an error message into *pzErrMsg.

** After a database is initialized, the DB_SchemaLoaded bit is set

** bit is set in the flags field of the Db structure.

int sqlite3Init(sqlite3 *db, char **pzErrMsg){

int i, rc;

int commit_internal = !(db->mDbFlags&DBFLAG_SchemaChange);

assert( sqlite3_mutex_held(db->mutex) );

assert( sqlite3BtreeHoldsMutex(db->aDb[0].pBt) );

assert( db->init.busy==0 );

ENC(db) = SCHEMA_ENC(db);

assert( db->nDb>0 );

/* Do the main schema first */

if( !DbHasProperty(db, 0, DB_SchemaLoaded) ){

rc = sqlite3InitOne(db, 0, pzErrMsg, 0);

if( rc ) return rc;

}

/* All other schemas after the main schema. The "temp" schema must be last */

for(i=db->nDb-1; i>0; i--){

assert( i==1 || sqlite3BtreeHoldsMutex(db->aDb[i].pBt) );

if( !DbHasProperty(db, i, DB_SchemaLoaded) ){

rc = sqlite3InitOne(db, i, pzErrMsg, 0);

if( rc ) return rc;

}

if( commit_internal ){

sqlite3CommitInternalChanges(db);

}

return SQLITE_OK;

}

** This routine is a no-op if the database schema is already initialized.

** Otherwise, the schema is loaded. An error code is returned.

int sqlite3ReadSchema(Parse *pParse){

int rc = SQLITE_OK;

sqlite3 *db = pParse->db;

assert( sqlite3_mutex_held(db->mutex) );

if( !db->init.busy ){

rc = sqlite3Init(db, &pParse->zErrMsg);

if( rc!=SQLITE_OK ){

pParse->rc = rc;

pParse->nErr++;

}else if( db->noSharedCache ){

db->mDbFlags |= DBFLAG_SchemaKnownOk;

}

return rc;

}

** Check schema cookies in all databases. If any cookie is out

** of date set pParse->rc to SQLITE_SCHEMA. If all schema cookies

** make no changes to pParse->rc.

static void schemaIsValid(Parse *pParse){

sqlite3 *db = pParse->db;

int iDb;

int rc;

int cookie;

assert( pParse->checkSchema );

assert( sqlite3_mutex_held(db->mutex) );

for(iDb=0; iDb<db->nDb; iDb++){

int openedTransaction = 0; /* True if a transaction is opened */

Btree *pBt = db->aDb[iDb].pBt; /* Btree database to read cookie from */

if( pBt==0 ) continue;

/* If there is not already a read-only (or read-write) transaction opened

** on the b-tree database, open one now. If a transaction is opened, it

** will be closed immediately after reading the meta-value. */

if( sqlite3BtreeTxnState(pBt)==SQLITE_TXN_NONE ){

rc = sqlite3BtreeBeginTrans(pBt, 0, 0);

if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){

sqlite3OomFault(db);

pParse->rc = SQLITE_NOMEM;

}

if( rc!=SQLITE_OK ) return;

openedTransaction = 1;

}

/* Read the schema cookie from the database. If it does not match the

** value stored as part of the in-memory schema representation,

** set Parse.rc to SQLITE_SCHEMA. */

sqlite3BtreeGetMeta(pBt, BTREE_SCHEMA_VERSION, (u32 *)&cookie);

assert( sqlite3SchemaMutexHeld(db, iDb, 0) );

if( cookie!=db->aDb[iDb].pSchema->schema_cookie ){

if( DbHasProperty(db, iDb, DB_SchemaLoaded) ) pParse->rc = SQLITE_SCHEMA;

sqlite3ResetOneSchema(db, iDb);

}

/* Close the transaction, if one was opened. */

if( openedTransaction ){

sqlite3BtreeCommit(pBt);

}

** Convert a schema pointer into the iDb index that indicates

** which database file in db->aDb[] the schema refers to.

** If the same database is attached more than once, the first

** attached database is returned.

int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){

int i = -32768;

/* If pSchema is NULL, then return -32768. This happens when code in

** expr.c is trying to resolve a reference to a transient table (i.e. one

** created by a sub-select). In this case the return value of this

** function should never be used.

** We return -32768 instead of the more usual -1 simply because using

** -32768 as the incorrect index into db->aDb[] is much

** more likely to cause a segfault than -1 (of course there are assert()

** statements too, but it never hurts to play the odds) and

** -32768 will still fit into a 16-bit signed integer.

assert( sqlite3_mutex_held(db->mutex) );

if( pSchema ){

for(i=0; 1; i++){

assert( i<db->nDb );

if( db->aDb[i].pSchema==pSchema ){

break;

}

assert( i>=0 && i<db->nDb );

}

return i;

}

** Free all memory allocations in the pParse object

void sqlite3ParseObjectReset(Parse *pParse){

sqlite3 *db = pParse->db;

assert( db!=0 );

assert( db->pParse==pParse );

assert( pParse->nested==0 );

#ifndef SQLITE_OMIT_SHARED_CACHE

if( pParse->aTableLock ) sqlite3DbNNFreeNN(db, pParse->aTableLock);

#endif

while( pParse->pCleanup ){

ParseCleanup *pCleanup = pParse->pCleanup;

pParse->pCleanup = pCleanup->pNext;

pCleanup->xCleanup(db, pCleanup->pPtr);

sqlite3DbNNFreeNN(db, pCleanup);

}

if( pParse->aLabel ) sqlite3DbNNFreeNN(db, pParse->aLabel);

if( pParse->pConstExpr ){

sqlite3ExprListDelete(db, pParse->pConstExpr);

}

assert( db->lookaside.bDisable >= pParse->disableLookaside );

db->lookaside.bDisable -= pParse->disableLookaside;

db->lookaside.sz = db->lookaside.bDisable ? 0 : db->lookaside.szTrue;

assert( pParse->db->pParse==pParse );

db->pParse = pParse->pOuterParse;

}

** Add a new cleanup operation to a Parser. The cleanup should happen when

** the parser object is destroyed. But, beware: the cleanup might happen

** immediately.

** Use this mechanism for uncommon cleanups. There is a higher setup

** cost for this mechanism (an extra malloc), so it should not be used

** for common cleanups that happen on most calls. But for less

** common cleanups, we save a single NULL-pointer comparison in

** sqlite3ParseObjectReset(), which reduces the total CPU cycle count.

** If a memory allocation error occurs, then the cleanup happens immediately.

** When either SQLITE_DEBUG or SQLITE_COVERAGE_TEST are defined, the

** pParse->earlyCleanup flag is set in that case. Calling code show verify

** that test cases exist for which this happens, to guard against possible

** use-after-free errors following an OOM. The preferred way to do this is

** to immediately follow the call to this routine with:

** testcase( pParse->earlyCleanup );

** This routine returns a copy of its pPtr input (the third parameter)

** except if an early cleanup occurs, in which case it returns NULL. So

** another way to check for early cleanup is to check the return value.

** Or, stop using the pPtr parameter with this call and use only its

** return value thereafter. Something like this:

** pObj = sqlite3ParserAddCleanup(pParse, destructor, pObj);

void *sqlite3ParserAddCleanup(

Parse *pParse, /* Destroy when this Parser finishes */

void (*xCleanup)(sqlite3*,void*), /* The cleanup routine */

void *pPtr /* Pointer to object to be cleaned up */

){

ParseCleanup *pCleanup;

if( sqlite3FaultSim(300) ){

pCleanup = 0;

sqlite3OomFault(pParse->db);

}else{

pCleanup = sqlite3DbMallocRaw(pParse->db, sizeof(*pCleanup));

}

if( pCleanup ){

pCleanup->pNext = pParse->pCleanup;

pParse->pCleanup = pCleanup;

pCleanup->pPtr = pPtr;

pCleanup->xCleanup = xCleanup;

}else{

xCleanup(pParse->db, pPtr);

pPtr = 0;

#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)

pParse->earlyCleanup = 1;

#endif

}

return pPtr;

}

** Turn bulk memory into a valid Parse object and link that Parse object

** into database connection db.

** Call sqlite3ParseObjectReset() to undo this operation.

** Caution: Do not confuse this routine with sqlite3ParseObjectInit() which

** is generated by Lemon.

void sqlite3ParseObjectInit(Parse *pParse, sqlite3 *db){

memset(PARSE_HDR(pParse), 0, PARSE_HDR_SZ);

memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);

assert( db->pParse!=pParse );

pParse->pOuterParse = db->pParse;

db->pParse = pParse;

pParse->db = db;

if( db->mallocFailed ) sqlite3ErrorMsg(pParse, "out of memory");

}

** Maximum number of times that we will try again to prepare a statement

** that returns SQLITE_ERROR_RETRY.

#ifndef SQLITE_MAX_PREPARE_RETRY

# define SQLITE_MAX_PREPARE_RETRY 25

#endif

** Compile the UTF-8 encoded SQL statement zSql into a statement handle.

static int sqlite3Prepare(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

u32 prepFlags, /* Zero or more SQLITE_PREPARE_* flags */

Vdbe *pReprepare, /* VM being reprepared */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

){

int rc = SQLITE_OK; /* Result code */

int i; /* Loop counter */

Parse sParse; /* Parsing context */

/* sqlite3ParseObjectInit(&sParse, db); // inlined for performance */

memset(PARSE_HDR(&sParse), 0, PARSE_HDR_SZ);

memset(PARSE_TAIL(&sParse), 0, PARSE_TAIL_SZ);

sParse.pOuterParse = db->pParse;

db->pParse = &sParse;

sParse.db = db;

if( pReprepare ){

sParse.pReprepare = pReprepare;

sParse.explain = sqlite3_stmt_isexplain((sqlite3_stmt*)pReprepare);

}else{

assert( sParse.pReprepare==0 );

}

assert( ppStmt && *ppStmt==0 );

if( db->mallocFailed ){

sqlite3ErrorMsg(&sParse, "out of memory");

db->errCode = rc = SQLITE_NOMEM;

goto end_prepare;

}

assert( sqlite3_mutex_held(db->mutex) );

/* For a long-term use prepared statement avoid the use of

** lookaside memory.

if( prepFlags & SQLITE_PREPARE_PERSISTENT ){

sParse.disableLookaside++;

DisableLookaside;

}

sParse.prepFlags = prepFlags & 0xff;

/* Check to verify that it is possible to get a read lock on all

** database schemas. The inability to get a read lock indicates that

** some other database connection is holding a write-lock, which in

** turn means that the other connection has made uncommitted changes

** to the schema.

** Were we to proceed and prepare the statement against the uncommitted

** schema changes and if those schema changes are subsequently rolled

** back and different changes are made in their place, then when this

** prepared statement goes to run the schema cookie would fail to detect

** the schema change. Disaster would follow.

** This thread is currently holding mutexes on all Btrees (because

** of the sqlite3BtreeEnterAll() in sqlite3LockAndPrepare()) so it

** is not possible for another thread to start a new schema change

** while this routine is running. Hence, we do not need to hold

** locks on the schema, we just need to make sure nobody else is

** holding them.

** Note that setting READ_UNCOMMITTED overrides most lock detection,

** but it does *not* override schema lock detection, so this all still

** works even if READ_UNCOMMITTED is set.

if( !db->noSharedCache ){

for(i=0; i<db->nDb; i++) {

Btree *pBt = db->aDb[i].pBt;

if( pBt ){

assert( sqlite3BtreeHoldsMutex(pBt) );

rc = sqlite3BtreeSchemaLocked(pBt);

if( rc ){

const char *zDb = db->aDb[i].zDbSName;

sqlite3ErrorWithMsg(db, rc, "database schema is locked: %s", zDb);

testcase( db->flags & SQLITE_ReadUncommit );

goto end_prepare;

}

#ifndef SQLITE_OMIT_VIRTUALTABLE

if( db->pDisconnect ) sqlite3VtabUnlockList(db);

#endif

if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){

char *zSqlCopy;

int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];

testcase( nBytes==mxLen );

testcase( nBytes==mxLen+1 );

if( nBytes>mxLen ){

sqlite3ErrorWithMsg(db, SQLITE_TOOBIG, "statement too long");

rc = sqlite3ApiExit(db, SQLITE_TOOBIG);

goto end_prepare;

}

zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);

if( zSqlCopy ){

sqlite3RunParser(&sParse, zSqlCopy);

sParse.zTail = &zSql[sParse.zTail-zSqlCopy];

sqlite3DbFree(db, zSqlCopy);

}else{

sParse.zTail = &zSql[nBytes];

}

}else{

sqlite3RunParser(&sParse, zSql);

}

assert( 0==sParse.nQueryLoop );

if( pzTail ){

*pzTail = sParse.zTail;

}

if( db->init.busy==0 ){

sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail-zSql), prepFlags);

}

if( db->mallocFailed ){

sParse.rc = SQLITE_NOMEM_BKPT;

sParse.checkSchema = 0;

}

if( sParse.rc!=SQLITE_OK && sParse.rc!=SQLITE_DONE ){

if( sParse.checkSchema && db->init.busy==0 ){

schemaIsValid(&sParse);

}

if( sParse.pVdbe ){

sqlite3VdbeFinalize(sParse.pVdbe);

}

assert( 0==(*ppStmt) );

rc = sParse.rc;

if( sParse.zErrMsg ){

sqlite3ErrorWithMsg(db, rc, "%s", sParse.zErrMsg);

sqlite3DbFree(db, sParse.zErrMsg);

}else{

sqlite3Error(db, rc);

}

}else{

assert( sParse.zErrMsg==0 );

*ppStmt = (sqlite3_stmt*)sParse.pVdbe;

rc = SQLITE_OK;

sqlite3ErrorClear(db);

}

/* Delete any TriggerPrg structures allocated while parsing this statement. */

while( sParse.pTriggerPrg ){

TriggerPrg *pT = sParse.pTriggerPrg;

sParse.pTriggerPrg = pT->pNext;

sqlite3DbFree(db, pT);

}

end_prepare:

sqlite3ParseObjectReset(&sParse);

return rc;

}

static int sqlite3LockAndPrepare(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

u32 prepFlags, /* Zero or more SQLITE_PREPARE_* flags */

Vdbe *pOld, /* VM being reprepared */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

){

int rc;

int cnt = 0;

#ifdef SQLITE_ENABLE_API_ARMOR

if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;

#endif

*ppStmt = 0;

if( !sqlite3SafetyCheckOk(db)||zSql==0 ){

return SQLITE_MISUSE_BKPT;

}

sqlite3_mutex_enter(db->mutex);

sqlite3BtreeEnterAll(db);

do{

/* Make multiple attempts to compile the SQL, until it either succeeds

** or encounters a permanent error. A schema problem after one schema

** reset is considered a permanent error. */

rc = sqlite3Prepare(db, zSql, nBytes, prepFlags, pOld, ppStmt, pzTail);

assert( rc==SQLITE_OK || *ppStmt==0 );

if( rc==SQLITE_OK || db->mallocFailed ) break;

cnt++;

}while( (rc==SQLITE_ERROR_RETRY && ALWAYS(cnt<=SQLITE_MAX_PREPARE_RETRY))

|| (rc==SQLITE_SCHEMA && (sqlite3ResetOneSchema(db,-1), cnt)==1) );

sqlite3BtreeLeaveAll(db);

assert( rc!=SQLITE_ERROR_RETRY );

rc = sqlite3ApiExit(db, rc);

assert( (rc&db->errMask)==rc );

db->busyHandler.nBusy = 0;

sqlite3_mutex_leave(db->mutex);

assert( rc==SQLITE_OK || (*ppStmt)==0 );

return rc;

}

** Rerun the compilation of a statement after a schema change.

** If the statement is successfully recompiled, return SQLITE_OK. Otherwise,

** if the statement cannot be recompiled because another connection has

** locked the sqlite3_schema table, return SQLITE_LOCKED. If any other error

** occurs, return SQLITE_SCHEMA.

int sqlite3Reprepare(Vdbe *p){

int rc;

sqlite3_stmt *pNew;

const char *zSql;

sqlite3 *db;

u8 prepFlags;

assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );

zSql = sqlite3_sql((sqlite3_stmt *)p);

assert( zSql!=0 ); /* Reprepare only called for prepare_v2() statements */

db = sqlite3VdbeDb(p);

assert( sqlite3_mutex_held(db->mutex) );

prepFlags = sqlite3VdbePrepareFlags(p);

rc = sqlite3LockAndPrepare(db, zSql, -1, prepFlags, p, &pNew, 0);

if( rc ){

if( rc==SQLITE_NOMEM ){

sqlite3OomFault(db);

}

assert( pNew==0 );

return rc;

}else{

assert( pNew!=0 );

}

sqlite3VdbeSwap((Vdbe*)pNew, p);

sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);

sqlite3VdbeResetStepResult((Vdbe*)pNew);

sqlite3VdbeFinalize((Vdbe*)pNew);

return SQLITE_OK;

}

** Two versions of the official API. Legacy and new use. In the legacy

** version, the original SQL text is not saved in the prepared statement

** and so if a schema change occurs, SQLITE_SCHEMA is returned by

** sqlite3_step(). In the new version, the original SQL text is retained

** and the statement is automatically recompiled if an schema change

** occurs.

int sqlite3_prepare(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

){

int rc;

rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,0,ppStmt,pzTail);

assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 ); /* VERIFY: F13021 */

return rc;

}

int sqlite3_prepare_v2(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

){

int rc;

/* EVIDENCE-OF: R-37923-12173 The sqlite3_prepare_v2() interface works

** exactly the same as sqlite3_prepare_v3() with a zero prepFlags

** parameter.

** Proof in that the 5th parameter to sqlite3LockAndPrepare is 0 */

rc = sqlite3LockAndPrepare(db,zSql,nBytes,SQLITE_PREPARE_SAVESQL,0,

ppStmt,pzTail);

assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );

return rc;

}

int sqlite3_prepare_v3(

sqlite3 *db, /* Database handle. */

const char *zSql, /* UTF-8 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_* flags */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const char **pzTail /* OUT: End of parsed string */

){

int rc;

/* EVIDENCE-OF: R-56861-42673 sqlite3_prepare_v3() differs from

** sqlite3_prepare_v2() only in having the extra prepFlags parameter,

** which is a bit array consisting of zero or more of the

** SQLITE_PREPARE_* flags.

** Proof by comparison to the implementation of sqlite3_prepare_v2()

** directly above. */

rc = sqlite3LockAndPrepare(db,zSql,nBytes,

SQLITE_PREPARE_SAVESQL|(prepFlags&SQLITE_PREPARE_MASK),

0,ppStmt,pzTail);

assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );

return rc;

}

#ifndef SQLITE_OMIT_UTF16

** Compile the UTF-16 encoded SQL statement zSql into a statement handle.

static int sqlite3Prepare16(

sqlite3 *db, /* Database handle. */

const void *zSql, /* UTF-16 encoded SQL statement. */

int nBytes, /* Length of zSql in bytes. */

u32 prepFlags, /* Zero or more SQLITE_PREPARE_* flags */

sqlite3_stmt **ppStmt, /* OUT: A pointer to the prepared statement */

const void **pzTail /* OUT: End of parsed string */

){

/* This function currently works by first transforming the UTF-16

** encoded string to UTF-8, then invoking sqlite3_prepare(). The

** tricky bit is figuring out the pointer to return in *pzTail.

char *zSql8;

const char *zTail8 = 0;

int rc = SQLITE_OK;

#ifdef SQLITE_ENABLE_API_ARMOR

if( ppStmt==0 ) return SQLITE_MISUSE_BKPT;

View remainder of file in raw view

sqlcipher/src/prepare.c at sqlite-release · sqlcipher/sqlcipher · GitHub

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