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Overview
Comment:When the final connection disconnects from a wal mode database, check that the database file has not been moved or unlinked before deleting the wal and shm files.
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SHA3-256:4761db83b6d3d57f281370899403c102e39ad0021d315dd6a6912d250436782a
User & Date: dan 2018-02-07 16:14:41
References
2018-02-07
18:45
Fix typo in comment. Skip tests added by check-in [4761db83b6] when running on Windows. check-in: 468a389c user: mistachkin tags: trunk
Context
2018-02-07
18:02
In extensions rtree, fts3 and fts5, ensure that when dynamic buffers are bound to persistent SQL statements using SQLITE_STATIC, the binding is replaced with an SQL NULL before the buffer is freed. Otherwise, a user may obtain a pointer to the persistent statement using sqlite3_next_stmt() and attempt to access the freed buffer using sqlite3_expanded_sql() or similar. check-in: 2a5f813b user: dan tags: trunk
16:14
When the final connection disconnects from a wal mode database, check that the database file has not been moved or unlinked before deleting the wal and shm files. check-in: 4761db83 user: dan tags: trunk
2018-02-05
21:02
Adjust the previous check-in, which modified the Win32 VFS, so that it works with SQLITE_OMIT_WAL. check-in: 36c2e67e user: mistachkin tags: trunk
Changes
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Changes to src/pager.c.

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  PgHdr *pNext;
  for(p=pPager->pMmapFreelist; p; p=pNext){
    pNext = p->pDirty;
    sqlite3_free(p);
  }
}


























/*
** Shutdown the page cache.  Free all memory and close all files.
**
** If a transaction was in progress when this routine is called, that
** transaction is rolled back.  All outstanding pages are invalidated
** and their memory is freed.  Any attempt to use a page associated
................................................................................
**
** This function always succeeds. If a transaction is active an attempt
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
  u8 *pTmp = (u8 *)pPager->pTmpSpace;

  assert( db || pagerUseWal(pPager)==0 );
  assert( assert_pager_state(pPager) );
  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pagerFreeMapHdrs(pPager);
  /* pPager->errCode = 0; */
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL


  assert( db || pPager->pWal==0 );
  sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags, pPager->pageSize,
      (db && (db->flags & SQLITE_NoCkptOnClose) ? 0 : pTmp)

  );



  pPager->pWal = 0;

#endif
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
    /* If it is open, sync the journal file before calling UnlockAndRollback.
    ** If this is not done, then an unsynced portion of the open journal 
................................................................................
  /* pPager->szMmap = SQLITE_DEFAULT_MMAP_SIZE // will be set by btree.c */

  *ppPager = pPager;
  return SQLITE_OK;
}


/* Verify that the database file has not be deleted or renamed out from
** under the pager.  Return SQLITE_OK if the database is still were it ought
** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
** code from sqlite3OsAccess()) if the database has gone missing.
*/
static int databaseIsUnmoved(Pager *pPager){
  int bHasMoved = 0;
  int rc;

  if( pPager->tempFile ) return SQLITE_OK;
  if( pPager->dbSize==0 ) return SQLITE_OK;
  assert( pPager->zFilename && pPager->zFilename[0] );
  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);
  if( rc==SQLITE_NOTFOUND ){
    /* If the HAS_MOVED file-control is unimplemented, assume that the file
    ** has not been moved.  That is the historical behavior of SQLite: prior to
    ** version 3.8.3, it never checked */
    rc = SQLITE_OK;
  }else if( rc==SQLITE_OK && bHasMoved ){
    rc = SQLITE_READONLY_DBMOVED;
  }
  return rc;
}


/*
** This function is called after transitioning from PAGER_UNLOCK to
** PAGER_SHARED state. It tests if there is a hot journal present in
** the file-system for the given pager. A hot journal is one that 
** needs to be played back. According to this function, a hot-journal
** file exists if the following criteria are met:







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  PgHdr *pNext;
  for(p=pPager->pMmapFreelist; p; p=pNext){
    pNext = p->pDirty;
    sqlite3_free(p);
  }
}

/* Verify that the database file has not be deleted or renamed out from
** under the pager.  Return SQLITE_OK if the database is still were it ought
** to be on disk.  Return non-zero (SQLITE_READONLY_DBMOVED or some other error
** code from sqlite3OsAccess()) if the database has gone missing.
*/
static int databaseIsUnmoved(Pager *pPager){
  int bHasMoved = 0;
  int rc;

  if( pPager->tempFile ) return SQLITE_OK;
  if( pPager->dbSize==0 ) return SQLITE_OK;
  assert( pPager->zFilename && pPager->zFilename[0] );
  rc = sqlite3OsFileControl(pPager->fd, SQLITE_FCNTL_HAS_MOVED, &bHasMoved);
  if( rc==SQLITE_NOTFOUND ){
    /* If the HAS_MOVED file-control is unimplemented, assume that the file
    ** has not been moved.  That is the historical behavior of SQLite: prior to
    ** version 3.8.3, it never checked */
    rc = SQLITE_OK;
  }else if( rc==SQLITE_OK && bHasMoved ){
    rc = SQLITE_READONLY_DBMOVED;
  }
  return rc;
}


/*
** Shutdown the page cache.  Free all memory and close all files.
**
** If a transaction was in progress when this routine is called, that
** transaction is rolled back.  All outstanding pages are invalidated
** and their memory is freed.  Any attempt to use a page associated
................................................................................
**
** This function always succeeds. If a transaction is active an attempt
** is made to roll it back. If an error occurs during the rollback 
** a hot journal may be left in the filesystem but no error is returned
** to the caller.
*/
int sqlite3PagerClose(Pager *pPager, sqlite3 *db){
  u8 *pTmp = (u8*)pPager->pTmpSpace;

  assert( db || pagerUseWal(pPager)==0 );
  assert( assert_pager_state(pPager) );
  disable_simulated_io_errors();
  sqlite3BeginBenignMalloc();
  pagerFreeMapHdrs(pPager);
  /* pPager->errCode = 0; */
  pPager->exclusiveMode = 0;
#ifndef SQLITE_OMIT_WAL
  {
    u8 *a = 0;
    assert( db || pPager->pWal==0 );

    if( db && 0==(db->flags & SQLITE_NoCkptOnClose) 
     && SQLITE_OK==databaseIsUnmoved(pPager)
    ){
      a = pTmp;
    }
    sqlite3WalClose(pPager->pWal, db, pPager->walSyncFlags, pPager->pageSize,a);
    pPager->pWal = 0;
  }
#endif
  pager_reset(pPager);
  if( MEMDB ){
    pager_unlock(pPager);
  }else{
    /* If it is open, sync the journal file before calling UnlockAndRollback.
    ** If this is not done, then an unsynced portion of the open journal 
................................................................................
  /* pPager->szMmap = SQLITE_DEFAULT_MMAP_SIZE // will be set by btree.c */

  *ppPager = pPager;
  return SQLITE_OK;
}



























/*
** This function is called after transitioning from PAGER_UNLOCK to
** PAGER_SHARED state. It tests if there is a hot journal present in
** the file-system for the given pager. A hot journal is one that 
** needs to be played back. According to this function, a hot-journal
** file exists if the following criteria are met:

Changes to test/nockpt.test.

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} {1 2 3 4 5 6 7 8 9}

do_execsql_test 1.13 { PRAGMA main.journal_mode } {wal}
do_test 1.14 { sqlite3_db_config db NO_CKPT_ON_CLOSE 1 } {1}
do_execsql_test 1.14 { PRAGMA main.journal_mode = delete } {delete}
do_test 1.15 { file exists test.db-wal } {0}

















































































finish_test







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} {1 2 3 4 5 6 7 8 9}

do_execsql_test 1.13 { PRAGMA main.journal_mode } {wal}
do_test 1.14 { sqlite3_db_config db NO_CKPT_ON_CLOSE 1 } {1}
do_execsql_test 1.14 { PRAGMA main.journal_mode = delete } {delete}
do_test 1.15 { file exists test.db-wal } {0}

#-------------------------------------------------------------------------
# Test an unusual scenario:
#
#   1. A wal mode db is opened and written. Then sqlite3_close_v2() used
#      to close the db handle while there is still an unfinalized
#      statement (so the db handle stays open).
#
#   2. The db, wal and *-shm files are deleted from the file system.
#
#   3. Another connection creates a new wal mode db at the same file-system
#      location as the previous one.
#
#   4. The statement left unfinalized in (1) is finalized.
#
# The test is to ensure that the connection left open in step (1) does
# not try to delete the wal file from the file-system as part of step
# 4.
#
reset_db
db close

# Open a connection on a wal database. Write to it a bit. Then prepare
# a statement and call sqlite3_close_v2() (so that the statement handle
# holds the db connection open).
#
set ::db1 [sqlite3_open_v2 test.db SQLITE_OPEN_READWRITE ""]
do_test 2.0 {
  lindex [
    sqlite3_exec $::db1 {
      PRAGMA journal_mode = wal;
      CREATE TABLE t1(x PRIMARY KEY, y UNIQUE, z);
      INSERT INTO t1 VALUES(1, 2, 3);
      PRAGMA wal_checkpoint;
    }] 0
} {0}
set ::stmt [sqlite3_prepare $::db1 "SELECT * FROM t1" -1 dummy]
sqlite3_close_v2 $::db1

# Delete the database, wal and shm files.
#
forcedelete test.db test.db-wal test.db-shm

# Open and populate a new database file at the same file-system location
# as the one just deleted. Contrive a partial checkpoint on it.
#
sqlite3 db  test.db
sqlite3 db2 test.db
do_execsql_test 2.1 {
  PRAGMA journal_mode = wal;
  CREATE TABLE y1(a PRIMARY KEY, b UNIQUE, c);
  INSERT INTO y1 VALUES('a', 'b', 'c');
  INSERT INTO y1 VALUES('d', 'e', 'f');
} {wal}
do_execsql_test -db db2 2.2 {
  BEGIN;
    SELECT * FROM y1;
} {a b c d e f}
do_execsql_test 2.3 {
  UPDATE y1 SET c='g' WHERE a='d';
  PRAGMA wal_checkpoint;
} {0 11 10}
do_execsql_test -db db2 2.4 {
  COMMIT
}

# Finalize the statement handle, causing the first connection to be
# closed. Test that this has not corrupted the database file by 
# deleting the new wal file from the file-system. If it has, this
# test should fail with an IO or corruption error.
#
do_test 2.5 {
  sqlite3_finalize $::stmt
  sqlite3 db3 test.db
  execsql { 
    PRAGMA integrity_check; 
    SELECT * FROM y1;
  } db3
} {ok a b c d e g}


finish_test