SQLite

/*
** 2004 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.
**
*************************************************************************
** $Id: btree.c,v 1.588 2009/04/02 18:28:08 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

}
#endif /* !SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Release all the table locks (locks obtained via calls to
** the setSharedCacheTableLock() procedure) held by Btree handle p.
**
** This function assumes that handle p has an open read or write 
** transaction. If it does not, then the BtShared.isPending variable
** may be incorrectly cleared.
*/
static void clearAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;
  BtLock **ppIter = &pBt->pLock;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( p->sharable || 0==*ppIter );
  assert( p->inTrans>0 );

  while( *ppIter ){
    BtLock *pLock = *ppIter;
    assert( pBt->isExclusive==0 || pBt->pWriter==pLock->pBtree );
    assert( pLock->pBtree->inTrans>=pLock->eLock );
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      sqlite3_free(pLock);
    }else{
      ppIter = &pLock->pNext;
    }
  }

set_child_ptrmaps_out:
  pPage->isInit = isInitOrig;
  return rc;
}

/*
** Somewhere on pPage, which is guaranteed to be a btree page, not an overflow
** page, is a pointer to page iFrom. Modify this pointer so that it points to
** iTo. Parameter eType describes the type of pointer to be modified, as 
** follows:
**
** PTRMAP_BTREE:     pPage is a btree-page. The pointer points at a child 
**                   page of pPage.
**

** number of pages the database file will contain after this 
** process is complete.
*/
static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg){
  Pgno nFreeList;           /* Number of pages still on the free-list */

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( iLastPg>nFin );

  if( !PTRMAP_ISPAGE(pBt, iLastPg) && iLastPg!=PENDING_BYTE_PAGE(pBt) ){
    int rc;
    u8 eType;
    Pgno iPtrPage;

    nFreeList = get4byte(&pBt->pPage1->aData[36]);
    if( nFreeList==0 ){
      return SQLITE_DONE;
    }

    rc = ptrmapGet(pBt, iLastPg, &eType, &iPtrPage);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
    if( rc!=SQLITE_OK ){
      sqlite3BtreeLeave(p);
      return rc;
    }
    pBt->inTransaction = TRANS_READ;
  }


  /* If the handle has any kind of transaction open, decrement the transaction
  ** count of the shared btree. If the transaction count reaches 0, set
  ** the shared state to TRANS_NONE. The unlockBtreeIfUnused() call below
  ** will unlock the pager.
  */
  if( p->inTrans!=TRANS_NONE ){
    clearAllSharedCacheTableLocks(p);
    pBt->nTransaction--;
    if( 0==pBt->nTransaction ){
      pBt->inTransaction = TRANS_NONE;
    }
  }

  /* Set the handles current transaction state to TRANS_NONE and unlock

    ** we cannot simply return the error to the caller. Instead, abort 
    ** all queries that may be using any of the cursors that failed to save.
    */
    sqlite3BtreeTripAllCursors(p, rc);
  }
#endif
  btreeIntegrity(p);


  if( p->inTrans==TRANS_WRITE ){
    int rc2;

    assert( TRANS_WRITE==pBt->inTransaction );
    rc2 = sqlite3PagerRollback(pBt->pPager);
    if( rc2!=SQLITE_OK ){

      releasePage(pPage1);
    }
    assert( countWriteCursors(pBt)==0 );
    pBt->inTransaction = TRANS_READ;
  }

  if( p->inTrans!=TRANS_NONE ){
    clearAllSharedCacheTableLocks(p);
    assert( pBt->nTransaction>0 );
    pBt->nTransaction--;
    if( 0==pBt->nTransaction ){
      pBt->inTransaction = TRANS_NONE;
    }
  }

  /* If autovacuumed is disabled in this build but we are trying to 
  ** access an autovacuumed database, then make the database readonly. 
  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==4 && *pMeta>0 ) pBt->readOnly = 1;
#endif

  /* If there is currently an open transaction, grab a read-lock 
  ** on page 1 of the database file. This is done to make sure that
  ** no other connection can modify the meta value just read from
  ** the database until the transaction is concluded.
  */
  if( p->inTrans>0 ){
    rc = setSharedCacheTableLock(p, 1, READ_LOCK);
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Write meta-information back into the database.  Meta[0] is
** read-only and may not be written.

#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests to make sure SQLite does not crash or
# segfault if it sees a corrupt database file.
#
# $Id: corrupt2.test,v 1.19 2009/04/02 18:28:08 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# The following tests - corrupt2-1.* - create some databases corrupted in
# specific ways and ensure that SQLite detects them as corrupt.
#

  do_test corrupt2-10.1 {
    catchsql { SELECT * FROM t2 }
  } {1 {malformed database schema (t2)}}
  do_test corrupt2-10.2 {
    sqlite3_errcode db
  } {SQLITE_CORRUPT}
}

corruption_test -sqlprep {
  PRAGMA auto_vacuum = incremental;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  CREATE TABLE t2(a INTEGER PRIMARY KEY, b);
  INSERT INTO t1 VALUES(1, randstr(100,100));
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t2 SELECT * FROM t1;
  DELETE FROM t1;
} -corrupt {
  set offset [expr [file size corrupt.db] - 1024]
  hexio_write corrupt.db $offset FF 
  hexio_write corrupt.db 24   12345678
} -test {
  do_test corrupt2-11.1 {
    catchsql { PRAGMA incremental_vacuum }
  } {1 {database disk image is malformed}}
}

corruption_test -sqlprep {
  PRAGMA auto_vacuum = incremental;
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  CREATE TABLE t2(a INTEGER PRIMARY KEY, b);
  INSERT INTO t1 VALUES(1, randstr(100,100));
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t1 SELECT NULL, randstr(100,100) FROM t1;
  INSERT INTO t2 SELECT * FROM t1;
  DELETE FROM t1;
} -corrupt {
  set pgno [expr [file size corrupt.db] / 1024]
  hexio_write corrupt.db [expr 1024+5*($pgno-3)] 03 
  hexio_write corrupt.db 24   12345678
} -test {
  do_test corrupt2-12.1 {
    catchsql { PRAGMA incremental_vacuum }
  } {1 {database disk image is malformed}}
}

finish_test

# 2009 April 01
#
# 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.
#
#***********************************************************************
#
# $Id: shared6.test,v 1.3 2009/04/02 18:28:08 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
ifcapable !shared_cache { finish_test ; return }

do_test shared6-1.1.1 {
  execsql {
    CREATE TABLE t1(a, b);
    CREATE TABLE t2(c, d);
    CREATE TABLE t3(e, f);
  }
  db close
} {}
do_test shared6-1.1.2 {
  set ::enable_shared_cache [sqlite3_enable_shared_cache 1]
  sqlite3_enable_shared_cache
} {1}

do_test shared6-1.1.3 {

} {1 {database table is locked: t1}}

do_test shared6-1.X {
  db1 close
  db2 close
} {}

#-------------------------------------------------------------------------
# The following tests - shared6-2.* - test that two database connections
# that connect to the same file using different VFS implementations do
# not share a cache.
#
if {$::tcl_platform(platform) eq "unix"} {
  do_test shared6-2.1 {
    sqlite3 db1 test.db -vfs unix
    sqlite3 db2 test.db -vfs unix
    sqlite3 db3 test.db -vfs unix-none
    sqlite3 db4 test.db -vfs unix-none
  } {}

  do_test shared6-2.X {
    db1 close
    db2 close
    db3 close
    db4 close
  } {}
}

#-------------------------------------------------------------------------
# Test that it is possible to open an exclusive transaction while 
# already holding a read-lock on the database file. And that it is
# not possible if some other connection holds such a lock.
#
do_test shared6-3.1 {
  sqlite3 db1 test.db
  sqlite3 db2 test.db
  sqlite3 db3 test.db
} {}
db1 eval {SELECT * FROM t1} {
  # Within this block [db1] is holding a read-lock on t1. Test that
  # this means t1 cannot be written by [db2].
  #
  do_test shared6-3.2 {
    catchsql { INSERT INTO t1 VALUES(1, 2) } db2
  } {1 {database table is locked: t1}}

  do_test shared6-3.3 {
    execsql { BEGIN EXCLUSIVE } db1
  } {}
  break
}
do_test shared6-3.4 {
  catchsql { SELECT * FROM t1 } db2
} {1 {database schema is locked: main}}
do_test shared6-3.5 {
  execsql COMMIT db1
} {}
db2 eval {SELECT * FROM t1} {
  do_test shared6-3.6 {
    catchsql { BEGIN EXCLUSIVE } db1
  } {1 {database table is locked}}
  break
}
do_test shared6-3.7 {
  execsql { BEGIN } db1
  execsql { BEGIN } db2
} {}
db2 eval {SELECT * FROM t1} {
  do_test shared6-3.8 {
    catchsql { INSERT INTO t1 VALUES(1, 2) } db1
  } {1 {database table is locked: t1}}
  break
}
do_test shared6-3.9 {
  execsql { BEGIN ; ROLLBACK } db3
} {}
do_test shared6-3.10 {
  catchsql { SELECT * FROM t1 } db3
} {1 {database table is locked}}
do_test shared6-3.X {
  db1 close
  db2 close
  db3 close
} {}

do_test shared6-4.1 {
  #file delete -force test.db test.db-journal
  sqlite3 db1 test.db
  sqlite3 db2 test.db

  set ::STMT [sqlite3_prepare_v2 db1 "SELECT * FROM t1" -1 DUMMY]
  execsql { CREATE TABLE t5(a, b) } db2
} {}
do_test shared6-4.2 {
  sqlite3_finalize $::STMT
} {SQLITE_OK}
do_test shared6-4.X {
  
  db1 close
  db2 close
} {}

sqlite3_enable_shared_cache $::enable_shared_cache
finish_test