SQLite

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.369 2007/08/23 11:07:10 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

    nSector = sqlite3OsSectorSize(fd);
    nPage = pPager->pageSize;
  }

  assert(SQLITE_IOCAP_ATOMIC512==(512>>8));
  assert(SQLITE_IOCAP_ATOMIC64K==(65536>>8));

  if( !fd->pMethods || (dc&(SQLITE_IOCAP_ATOMIC|(nPage>>8))&&nSector<=nPage) ){
    return JOURNAL_HDR_SZ(pPager) + JOURNAL_PG_SZ(pPager);
  }
  return 0;
}
#endif

/*

** is used to test the ability of SQLite to recover from those situations.
*/
#if SQLITE_TEST          /* This file is used for the testing only */
#include "sqliteInt.h"
#include "tcl.h"

#ifndef SQLITE_OMIT_DISKIO  /* This file is a no-op if disk I/O is disabled */

/* #define TRACE_CRASHTEST */

typedef struct CrashFile CrashFile;
typedef struct CrashGlobal CrashGlobal;
typedef struct WriteBuffer WriteBuffer;

/*
** Method:

  if( !isCrash ){
    for(pWrite=g.pWriteList; pWrite; pWrite=pWrite->pNext){
      if( pWrite->pFile==pFile ){
        pFinal = pWrite;
      }
    }
  }

#ifdef TRACE_CRASHTEST
  printf("Sync %s (is %s crash)\n", pFile->zName, (isCrash?"a":"not a"));
#endif

  sqlite3OsFileSize((sqlite3_file *)pFile, &iSize);

  ppPtr = &g.pWriteList;
  for(pWrite=*ppPtr; rc==SQLITE_OK && pWrite; pWrite=*ppPtr){
    sqlite3_file *pRealFile = pWrite->pFile->pRealFile;

          rc = sqlite3OsWrite(
              pRealFile, pWrite->zBuf, pWrite->nBuf, pWrite->iOffset
          );
        }else{
          rc = sqlite3OsTruncate(pRealFile, pWrite->iOffset);
        }
        *ppPtr = pWrite->pNext;
#ifdef TRACE_CRASHTEST
        if( isCrash ){
          printf("Writing %d bytes @ %d\n", pWrite->nBuf, (int)pWrite->iOffset);
        }
#endif
        sqlite3_free(pWrite);
        break;
      }
      case 2: {               /* Do nothing */
        ppPtr = &pWrite->pNext;
#ifdef TRACE_CRASHTEST
        if( isCrash ){
          printf("Omiting %d bytes @ %d\n", pWrite->nBuf, (int)pWrite->iOffset);
        }
#endif
        break;
      }
      case 3: {               /* Trash sectors */
        u8 *zGarbage;
        int iFirst = (pWrite->iOffset/g.iSectorSize);
        int iLast = (pWrite->iOffset+pWrite->nBuf-1)/g.iSectorSize;

        assert(pWrite->zBuf);

#ifdef TRACE_CRASHTEST
        printf("Trashing %d sectors @ sector %d\n", 1+iLast-iFirst, iFirst);
#endif

        zGarbage = sqlite3_malloc(g.iSectorSize);
        if( zGarbage ){
          sqlite3_int64 i;
          for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
            sqlite3Randomness(g.iSectorSize, zGarbage); 
            rc = sqlite3OsWrite(

# 2007 August 23
#
# 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: crash3.test,v 1.1 2007/08/23 11:07:10 danielk1977 Exp $

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

ifcapable !crashtest {
  finish_test
  return
}

proc do_test2 {name tcl res1 res2} {
  set script [subst -nocommands {
    do_test $name {
      set res1 {$res1}
      set res2 {$res2}
      set res [eval {$tcl}]
      if {[set res] eq [set res1] || [set res] eq [set res2]} {
        set res "{[set res1]} or {[set res2]}"
      }
      set res
    } {{$res1} or {$res2}}
  }]
  uplevel $script
}

# Each iteration of the following loop sets up the database to contain
# the following schema and data:
#
#    CREATE TABLE abc(a, b, c);
#    INSERT INTO abc VALUES(1, 2, 3);
#
# Then execute the SQL statement, scheduling a crash for part-way through
# the first sync() of either the database file or the journal file (often
# the journal file is not required - meaning no crash occurs).
#
# After the crash (or absence of a crash), open the database and 
# verify that:
#
#   * The integrity check passes, and
#   * The contents of table abc is either {1 2 3} or the value specified
#     to the right of the SQL statement below.
#
# The procedure is repeated 10 times for each SQL statement. Five times
# with the crash scheduled for midway through the first journal sync (if 
# any), and five times with the crash midway through the database sync.
#
set tn 1
foreach {sql res2} [list \
  {INSERT INTO abc VALUES(4, 5, 6)}                    {1 2 3 4 5 6} \
  {DELETE FROM abc}                                    {}    \
  {INSERT INTO abc SELECT * FROM abc}                  {1 2 3 1 2 3} \
  {UPDATE abc SET a = 2}                               {2 2 3}       \
  {INSERT INTO abc VALUES(4, 5, randstr(1000,1000))}   {n/a} \
  {CREATE TABLE def(d, e, f)}                          {n/a} \
] {
  for {set ii 0} {$ii < 10} {incr ii} {

    db close
    file delete -force test.db test.db-journal
    sqlite3 db test.db
    do_test crash3-1.$tn.1 {
      execsql {
        BEGIN;
        CREATE TABLE abc(a, b, c);
        INSERT INTO abc VALUES(1, 2, 3);
        COMMIT;
      }
    } {}
    db close
  
    set crashfile test.db
    if {($ii%2)==0} { append crashfile -journal }
    set rand "SELECT randstr($tn,$tn);"
    do_test crash3-1.$tn.2 [subst {
      crashsql -file $crashfile -char atomic {$rand $sql}
      sqlite3 db test.db
      execsql { PRAGMA integrity_check; }
    }] {ok}
  
    do_test2 crash3-1.$tn.3 {
      execsql { SELECT * FROM abc }
    } {1 2 3} $res2

    incr tn
  }
}

finish_test

#
#***********************************************************************
#
# The focus of this file is testing some specific characteristics of the 
# IO traffic generated by SQLite (making sure SQLite is not writing out
# more database pages than it has to, stuff like that).
#
# $Id: io.test,v 1.4 2007/08/23 11:07:10 danielk1977 Exp $

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

# Test summary:
#
# io-1.* -  Test that quick-balance does not journal pages unnecessarily.

} {}
do_test io-2.8.3 {
  execsql {
    ROLLBACK;
    SELECT * FROM abc;
  }
} {1 2 3 4 5 6 7 8}

# Test that the atomic write optimisation is not enabled if the sector
# size is larger than the page-size.
#
do_test io-2.9.1 {
  sqlite3_simulate_device -char atomic -sectorsize 2048
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(9, 10);
  }
  file exists test.db-journal
} {1}
do_test io-2.9.2 {
  execsql { ROLLBACK; }
  db close
  file delete -force test.db test.db-journal
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 2048;
    CREATE TABLE abc(a, b);
  }
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(9, 10);
  }
  file exists test.db-journal
} {0}
do_test io-2.9.3 {
  execsql { COMMIT }
} {}

# Test a couple of the more specific IOCAP_ATOMIC flags 
# (i.e IOCAP_ATOMIC2K etc.).
#
do_test io-2.10.1 {
  sqlite3_simulate_device -char atomic1k
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(11, 12);
  }
  file exists test.db-journal
} {1}
do_test io-2.10.2 {
  execsql { ROLLBACK }
  sqlite3_simulate_device -char atomic2k
  execsql {
    BEGIN;
    INSERT INTO abc VALUES(11, 12);
  }
  file exists test.db-journal
} {0}

sqlite3_simulate_device -char {} -sectorsize 0

finish_test

# 2001 September 15
#
# 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 implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.88 2007/08/23 11:07:10 danielk1977 Exp $

# Make sure tclsqlite3 was compiled correctly.  Abort now with an
# error message if not.
#
if {[sqlite3 -tcl-uses-utf]} {
  if {"\u1234"=="u1234"} {
    puts stderr "***** BUILD PROBLEM *****"

#
# The return value is a list of two elements. The first element is a
# boolean, indicating whether or not the process actually crashed or
# reported some other error. The second element in the returned list is the
# error message. This is "child process exited abnormally" if the crash
# occured.
#
#   crashsql -delay CRASHDELAY -file CRASHFILE ?-blocksize BLOCKSIZE? $sql
#
proc crashsql {args} {
  if {$::tcl_platform(platform)!="unix"} {
    error "crashsql should only be used on unix"
  }

  set blocksize ""
  set crashdelay 1
  set crashfile ""
  set dc ""
  set sql [lindex $args end]
  
  for {set ii 0} {$ii < [llength $args]-1} {incr ii 2} {
    set z [lindex $args $ii]
    set n [string length $z]
    set z2 [lindex $args [expr $ii+1]]

    if     {$n>1 && [string first $z -delay]==0}     {set crashdelay $z2} \
    elseif {$n>1 && [string first $z -file]==0}      {set crashfile $z2}  \
    elseif {$n>1 && [string first $z -blocksize]==0} {set blocksize "-s $z2" } \
    elseif {$n>1 && [string first $z -characteristics]==0} {set dc "-c {$z2}" } \
    else   { error "Unrecognized option: $z" }
  }

  if {$crashfile eq ""} {
    error "Compulsory option -file missing"
  }

  set cfile [file join [pwd] $crashfile]

  set f [open crash.tcl w]
  puts $f "sqlite3_crashparams $blocksize $dc $crashdelay $cfile"
  puts $f "set sqlite_pending_byte $::sqlite_pending_byte"
  puts $f "sqlite3 db test.db"

  # This block sets the cache size of the main database to 10
  # pages. This is done in case the build is configured to omit
  # "PRAGMA cache_size".
  puts $f {db eval {SELECT * FROM sqlite_master;}}