# 2004 August 30
#
# 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 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.  It creates a base
# data base file, then tests that single byte corruptions in 
# increasingly larger quantities are handled gracefully.
#
# $Id: corruptC.test,v 1.14 2009/07/11 06:55:34 danielk1977 Exp $

catch {forcedelete test.db test.db-journal test.bu}

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

# Do not use a codec for tests in this file, as the database file is
# manipulated directly using tcl scripts (using the [hexio_write] command).
#
do_not_use_codec

# These tests deal with corrupt database files
#
database_may_be_corrupt

# Construct a compact, dense database for testing.
#
do_test corruptC-1.1 {
  execsql {
    PRAGMA auto_vacuum = 0;
    PRAGMA legacy_file_format=1;
    BEGIN;
    CREATE TABLE t1(x,y);
    INSERT INTO t1 VALUES(1,1);
    INSERT OR IGNORE INTO t1 SELECT x*2,y FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*3,y FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*5,y FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*7,y FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*11,y FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*13,y FROM t1;
    CREATE INDEX t1i1 ON t1(x);
    CREATE TABLE t2 AS SELECT x,2 as y FROM t1 WHERE rowid%5!=0;
    COMMIT;
  }
} {}

ifcapable {integrityck} {
  integrity_check corruptC-1.2
}

# Generate random integer
#
proc random {range} {
  return [expr {round(rand()*$range)}]
}

# Setup for the tests.  Make a backup copy of the good database in test.bu.
#
db close
forcecopy test.db test.bu
sqlite3 db test.db
set fsize [file size test.db]

# Set a quasi-random random seed. 
if {[info exists ::G(issoak)]} {
  # If we are doing SOAK tests, we want a different
  # random seed for each run.  Ideally we would like 
  # to use [clock clicks] or something like that here.
  set qseed [file mtime test.db]
} else {
  # If we are not doing soak tests,
  # make it repeatable.
  set qseed 0
}
expr srand($qseed)

#
# First test some specific corruption tests found from earlier runs
# with specific seeds.
#

# test that a corrupt content offset size is handled (seed 5577)
do_test corruptC-2.1 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 2053 [format %02x 0x04]

  sqlite3 db test.db
  catchsql {PRAGMA integrity_check}
} {0 {{*** in database main ***
Page 3: free space corruption}}}

# test that a corrupt content offset size is handled (seed 5649)
#
# Update 2016-12-27:  As of check-in [0b86fbca66] "In sqlite3BtreeInsert() when
# replacing a re-existing row, try to overwrite the cell directly rather than
# deallocate and reallocate the cell" on 2016-12-09, this test case no longer
# detects the offset size problem during the UPDATE.  We have to run a subsequent
# integrity_check to see it.
do_test corruptC-2.2 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 27   [format %02x 0x08]
  hexio_write test.db 233  [format %02x 0x6a]
  hexio_write test.db 328  [format %02x 0x67]
  hexio_write test.db 750  [format %02x 0x1f]
  hexio_write test.db 1132 [format %02x 0x52]
  hexio_write test.db 1133 [format %02x 0x84]
  hexio_write test.db 1220 [format %02x 0x01]
  hexio_write test.db 3688 [format %02x 0xc1]
  hexio_write test.db 3714 [format %02x 0x58]
  hexio_write test.db 3746 [format %02x 0x9a]

  sqlite3 db test.db
  db eval {UPDATE t1 SET y=1}
  db eval {PRAGMA integrity_check}
} {/Offset .* out of range/}

# test that a corrupt free cell size is handled (seed 13329)
do_test corruptC-2.3 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 1094 [format %02x 0x76]

  sqlite3 db test.db
  catchsql {UPDATE t1 SET y=1}
} {1 {database disk image is malformed}}

# test that a corrupt free cell size is handled (seed 169571)
do_test corruptC-2.4 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 3119 [format %02x 0xdf]

  sqlite3 db test.db
  catchsql {UPDATE t2 SET y='abcdef-uvwxyz'}
} {1 {database disk image is malformed}}

# test that a corrupt free cell size is handled (seed 169571)
do_test corruptC-2.5 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 3119 [format %02x 0xdf]
  hexio_write test.db 4073 [format %02x 0xbf]

  sqlite3 db test.db
  catchsql {BEGIN; UPDATE t2 SET y='abcdef-uvwxyz'; ROLLBACK;}
  catchsql {PRAGMA integrity_check}
} {0 {{*** in database main ***
On tree page 4 cell 19: Extends off end of page} {database disk image is malformed}}}

# {0 {{*** in database main ***
# Corruption detected in cell 710 on page 4
# Multiple uses for byte 661 of page 4
# Fragmented space is 249 byte reported as 21 on page 4}}}

# test that a corrupt free cell size is handled (seed 169595)
do_test corruptC-2.6 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 619 [format %02x 0xe2]
  hexio_write test.db 3150 [format %02x 0xa8]

  sqlite3 db test.db
  catchsql {BEGIN; UPDATE t2 SET y='abcdef-uvwxyz'; ROLLBACK;}
} {1 {database disk image is malformed}}

# corruption (seed 178692)
do_test corruptC-2.7 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 3074 [format %02x 0xa0]

  sqlite3 db test.db
  catchsql {BEGIN; UPDATE t2 SET y='abcdef-uvwxyz'; ROLLBACK;}
} {1 {database disk image is malformed}}


# corruption (seed 179069)
# Obsolete.  With single-pass DELETE the corruption in the
# main database is not detected.
if 0 {
do_test corruptC-2.8 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 1393 [format %02x 0x7d]
  hexio_write test.db 84 [format %02x 0x19]
  hexio_write test.db 3287 [format %02x 0x3b]
  hexio_write test.db 2564 [format %02x 0xed]
  hexio_write test.db 2139 [format %02x 0x55]

  sqlite3 db test.db
  catchsql {BEGIN; DELETE FROM t1 WHERE x>13; ROLLBACK;}
} {1 {database disk image is malformed}}
}

# corruption (seed 170434)
#
# UPDATE: Prior to 3.8.2, this used to return SQLITE_CORRUPT. It no longer
# does. That is Ok, the point of these tests is to verify that no buffer
# overruns or overreads can be caused by corrupt databases.
do_test corruptC-2.9 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 2095 [format %02x 0xd6]

  sqlite3 db test.db
  catchsql {BEGIN; DELETE FROM t1 WHERE x>13; ROLLBACK;}
} {0 {}}

# corruption (seed 186504)
do_test corruptC-2.10 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 3130 [format %02x 0x02]
  
  sqlite3 db test.db
  catchsql {BEGIN; UPDATE t2 SET y='abcdef-uvwxyz'; ROLLBACK;}
} {1 {database disk image is malformed}}

# corruption (seed 1589)
do_test corruptC-2.11 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 55 [format %02x 0xa7]
  
  sqlite3 db test.db
  catchsql {BEGIN; CREATE TABLE t3 AS SELECT x,3 as y FROM t2 WHERE rowid%5!=0; ROLLBACK;}
} {1 {database disk image is malformed}}

# corruption (seed 14166)
do_test corruptC-2.12 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 974 [format %02x 0x2e]
  
  sqlite3 db test.db
  catchsql {SELECT count(*) FROM sqlite_master;}
} {1 {malformed database schema (t1i1) - corrupt database}}

# corruption (seed 218803)
do_test corruptC-2.13 {
  db close
  forcecopy test.bu test.db

  # insert corrupt byte(s)
  hexio_write test.db 102 [format %02x 0x12]
  
  sqlite3 db test.db
  catchsql {BEGIN; CREATE TABLE t3 AS SELECT x,3 as y FROM t2 WHERE rowid%5!=0; ROLLBACK;}
} {1 {database disk image is malformed}}

do_test corruptC-2.14 {
  db close
  forcecopy test.bu test.db

  sqlite3 db test.db
  set blob [string repeat abcdefghij 10000]
  execsql { INSERT INTO t1 VALUES (1, $blob) }

  sqlite3 db test.db
  set filesize [file size test.db]
  hexio_write test.db [expr $filesize-2048] 00000001
  catchsql {DELETE FROM t1 WHERE rowid = (SELECT max(rowid) FROM t1)}
} {1 {database disk image is malformed}}

# At one point this particular corrupt database was causing a buffer
# overread. Which caused a crash in a run of all.test once.
#
do_test corruptC-2.15 {
  db close
  forcecopy test.bu test.db
  hexio_write test.db 986 b9
  sqlite3 db test.db
  catchsql {SELECT count(*) FROM sqlite_master;}
} {1 {database disk image is malformed}}

#
# Now test for a series of quasi-random seeds.
# We loop over the entire file size and touch
# each byte at least once.
for {set tn 0} {$tn<$fsize} {incr tn 1} {

  # setup for test
  db close
  forcecopy test.bu test.db
  sqlite3 db test.db

  # Seek to a random location in the file, and write a random single byte
  # value.  Then do various operations on the file to make sure that
  # the database engine can handle the corruption gracefully.
  #
  set last 0
  for {set i 1} {$i<=512 && !$last} {incr i 1} {

    db close
    if {$i==1} {
      # on the first corrupt value, use location $tn
      # this ensures that we touch each location in the 
      # file at least once.
      set roffset $tn
    } else { 
      # insert random byte at random location
      set roffset [random $fsize]
    }
    set rbyte [format %02x [random 255]]

    # You can uncomment the following to have it trace
    # exactly how it's corrupting the file.  This is 
    # useful for generating the "seed specific" tests
    # above.
    # set rline "$roffset $rbyte"
    # puts stdout $rline

    hexio_write test.db $roffset $rbyte
    sqlite3 db test.db

    # do a few random operations to make sure that if 
    # they error, they error gracefully instead of crashing.
    do_test corruptC-3.$tn.($qseed).$i.1 {
      catchsql {SELECT count(*) FROM sqlite_master}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.2 {
      catchsql {SELECT count(*) FROM t1}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.3 {
      catchsql {SELECT count(*) FROM t1 WHERE x>13}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.4 {
      catchsql {SELECT count(*) FROM t2}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.5 {
      catchsql {SELECT count(*) FROM t2 WHERE x<13}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.6 {
      catchsql {BEGIN; UPDATE t1 SET y=1; ROLLBACK;}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.7 {
      catchsql {BEGIN; UPDATE t2 SET y='abcdef-uvwxyz'; ROLLBACK;}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.8 {
      catchsql {BEGIN; DELETE FROM t1 WHERE x>13; ROLLBACK;}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.9 {
      catchsql {BEGIN; DELETE FROM t2 WHERE x<13; ROLLBACK;}
      set x {}
    } {}
    do_test corruptC-3.$tn.($qseed).$i.10 {
      catchsql {BEGIN; CREATE TABLE t3 AS SELECT x,3 as y FROM t2 WHERE rowid%5!=0; ROLLBACK;}
      set x {}
    } {}

    # check the integrity of the database.
    # once the corruption is detected, we can stop.
    ifcapable {integrityck} {
      set res [ catchsql {PRAGMA integrity_check} ]
      set ans [lindex $res 1]
      if { [ string compare $ans "ok" ] != 0 } {
        set last -1
      }
    }
    # if we are not capable of doing an integrity check,
    # stop after corrupting 5 bytes.
    ifcapable {!integrityck} {
      if { $i > 5 } {
        set last -1
      }
    }

    # Check that no page references were leaked.
    # TBD:  need to figure out why this doesn't work
    # work with ROLLBACKs...
    if {0} {
      do_test corruptC-3.$tn.($qseed).$i.11 {
        set bt [btree_from_db db]
        db_enter db
        array set stats [btree_pager_stats $bt]
        db_leave db
        set stats(ref)
      } {0}
    }
  }
  # end for i

}
# end for tn

finish_test
