1# 2010 January 7 2# 3# The author disclaims copyright to this source code. In place of 4# a legal notice, here is a blessing: 5# 6# May you do good and not evil. 7# May you find forgiveness for yourself and forgive others. 8# May you share freely, never taking more than you give. 9# 10#*********************************************************************** 11# This file implements utility functions for SQLite library. 12# 13# This file attempts to restore the header of a journal. 14# This may be useful for rolling-back the last committed 15# transaction from a recovered journal. 16# 17 18package require sqlite3 19 20set parm_error 0 21set fix_chksums 0 22set dump_pages 0 23set db_name "" 24 25for {set i 0} {$i<$argc} {incr i} { 26 if {[lindex $argv $i] == "-fix_chksums"} { 27 set fix_chksums -1 28 } elseif {[lindex $argv $i] == "-dump_pages"} { 29 set dump_pages -1 30 } elseif {$db_name == ""} { 31 set db_name [lindex $argv $i] 32 set jrnl_name $db_name-journal 33 } else { 34 set parm_error -1 35 } 36} 37if {$parm_error || $db_name == ""} { 38 puts "USAGE: restore_jrnl.tcl \[-fix_chksums\] \[-dump_pages\] db_name" 39 puts "Example: restore_jrnl.tcl foo.sqlite" 40 return 41} 42 43# is there a way to determine this? 44set sectsz 512 45 46# Copy file $from into $to 47# 48proc copy_file {from to} { 49 file copy -force $from $to 50} 51 52# Execute some SQL 53# 54proc catchsql {sql} { 55 set rc [catch {uplevel [list db eval $sql]} msg] 56 list $rc $msg 57} 58 59# Perform a test 60# 61proc do_test {name cmd expected} { 62 puts -nonewline "$name ..." 63 set res [uplevel $cmd] 64 if {$res eq $expected} { 65 puts Ok 66 } else { 67 puts Error 68 puts " Got: $res" 69 puts " Expected: $expected" 70 } 71} 72 73# Calc checksum nonce from journal page data. 74# 75proc calc_nonce {jrnl_pgno} { 76 global sectsz 77 global db_pgsz 78 global jrnl_name 79 set jrnl_pg_offset [expr $sectsz+((4+$db_pgsz+4)*$jrnl_pgno)] 80 set nonce [hexio_get_int [hexio_read $jrnl_name [expr $jrnl_pg_offset+4+$db_pgsz] 4]] 81 for {set i [expr $db_pgsz-200]} {$i>0} {set i [expr $i-200]} { 82 set byte [hexio_get_int [hexio_read $jrnl_name [expr $jrnl_pg_offset+4+$i] 1]] 83 set nonce [expr $nonce-$byte] 84 } 85 return $nonce 86} 87 88# Calc checksum from journal page data. 89# 90proc calc_chksum {jrnl_pgno} { 91 global sectsz 92 global db_pgsz 93 global jrnl_name 94 global nonce 95 set jrnl_pg_offset [expr $sectsz+((4+$db_pgsz+4)*$jrnl_pgno)] 96 set chksum $nonce 97 for {set i [expr $db_pgsz-200]} {$i>0} {set i [expr $i-200]} { 98 set byte [hexio_get_int [hexio_read $jrnl_name [expr $jrnl_pg_offset+4+$i] 1]] 99 set chksum [expr $chksum+$byte] 100 } 101 return $chksum 102} 103 104# Print journal page data in hex dump form 105# 106proc dump_jrnl_page {jrnl_pgno} { 107 global sectsz 108 global db_pgsz 109 global jrnl_name 110 111 # print a header block for the page 112 puts [string repeat "-" 79] 113 set jrnl_pg_offset [expr $sectsz+((4+$db_pgsz+4)*$jrnl_pgno)] 114 set db_pgno [hexio_get_int [hexio_read $jrnl_name [expr $jrnl_pg_offset] 4]] 115 set chksum [hexio_get_int [hexio_read $jrnl_name [expr $jrnl_pg_offset+4+$db_pgsz] 4]] 116 set nonce [calc_nonce $jrnl_pgno] 117 puts [ format {jrnl_pg_offset: %08x (%d) jrnl_pgno: %d db_pgno: %d} \ 118 $jrnl_pg_offset $jrnl_pg_offset \ 119 $jrnl_pgno $db_pgno] 120 puts [ format {nonce: %08x chksum: %08x} \ 121 $nonce $chksum] 122 123 # now hex dump the data 124 # This is derived from the Tcler's WIKI 125 set fid [open $jrnl_name r] 126 fconfigure $fid -translation binary -encoding binary 127 seek $fid [expr $jrnl_pg_offset+4] 128 set data [read $fid $db_pgsz] 129 close $fid 130 for {set addr 0} {$addr<$db_pgsz} {set addr [expr $addr+16]} { 131 # get 16 bytes of data 132 set s [string range $data $addr [expr $addr+16]] 133 134 # Convert the data to hex and to characters. 135 binary scan $s H*@0a* hex ascii 136 137 # Replace non-printing characters in the data. 138 regsub -all -- {[^[:graph:] ]} $ascii {.} ascii 139 140 # Split the 16 bytes into two 8-byte chunks 141 regexp -- {(.{16})(.{0,16})} $hex -> hex1 hex2 142 143 # Convert the hex to pairs of hex digits 144 regsub -all -- {..} $hex1 {& } hex1 145 regsub -all -- {..} $hex2 {& } hex2 146 147 # Print the hex and ascii data 148 puts [ format {%08x %-24s %-24s %-16s} \ 149 $addr $hex1 $hex2 $ascii ] 150 } 151} 152 153# Setup for the tests. Make a backup copy of the files. 154# 155if [file exist $db_name.org] { 156 puts "ERROR: during back-up: $db_name.org exists already." 157 return; 158} 159if [file exist $jrnl_name.org] { 160 puts "ERROR: during back-up: $jrnl_name.org exists already." 161 return 162} 163copy_file $db_name $db_name.org 164copy_file $jrnl_name $jrnl_name.org 165 166set db_fsize [file size $db_name] 167set db_pgsz [hexio_get_int [hexio_read $db_name 16 2]] 168set db_npage [expr {$db_fsize / $db_pgsz}] 169 170set jrnl_fsize [file size $jrnl_name] 171set jrnl_npage [expr {($jrnl_fsize - $sectsz) / (4 + $db_pgsz + 4)}] 172 173# calculate checksum nonce for first page 174set nonce [calc_nonce 0] 175 176# verify all the pages in the journal use the same nonce 177for {set i 1} {$i<$jrnl_npage} {incr i} { 178 set tnonce [calc_nonce $i] 179 if {$tnonce != $nonce} { 180 puts "WARNING: different nonces: 0=$nonce $i=$tnonce" 181 if {$fix_chksums } { 182 set jrnl_pg_offset [expr $sectsz+((4+$db_pgsz+4)*$i)] 183 set tchksum [calc_chksum $i] 184 hexio_write $jrnl_name [expr $jrnl_pg_offset+4+$db_pgsz] [format %08x $tchksum] 185 puts "INFO: fixing chksum: $i=$tchksum" 186 } 187 } 188} 189 190# verify all the page numbers in the journal 191for {set i 0} {$i<$jrnl_npage} {incr i} { 192 set jrnl_pg_offset [expr $sectsz+((4+$db_pgsz+4)*$i)] 193 set db_pgno [hexio_get_int [hexio_read $jrnl_name $jrnl_pg_offset 4]] 194 if {$db_pgno < 1} { 195 puts "WARNING: page number < 1: $i=$db_pgno" 196 } 197 if {$db_pgno >= $db_npage} { 198 puts "WARNING: page number >= $db_npage: $i=$db_pgno" 199 } 200} 201 202# dump page data 203if {$dump_pages} { 204 for {set i 0} {$i<$jrnl_npage} {incr i} { 205 dump_jrnl_page $i 206 } 207} 208 209# write the 8 byte magic string 210hexio_write $jrnl_name 0 d9d505f920a163d7 211 212# write -1 for number of records 213hexio_write $jrnl_name 8 ffffffff 214 215# write 00 for checksum nonce 216hexio_write $jrnl_name 12 [format %08x $nonce] 217 218# write page count 219hexio_write $jrnl_name 16 [format %08x $db_npage] 220 221# write sector size 222hexio_write $jrnl_name 20 [format %08x $sectsz] 223 224# write page size 225hexio_write $jrnl_name 24 [format %08x $db_pgsz] 226 227# check the integrity of the database with the patched journal 228sqlite3 db $db_name 229do_test restore_jrnl-1.0 { 230 catchsql {PRAGMA integrity_check} 231} {0 ok} 232db close 233 234