WARNING PHP has an internal 2GB file size limitation for fseek()! Use the Ruby version below for images larger than 2GB!
Originally built to copy a block device (a mac mini in firewire mass storage mode) to an image file, excluding all-null blocks (sparse file) to save space.
Also contains examples of thousands-separator number formatting (i.e. 10,000,000) and human-readable magnitude number formatting (i.e. 10.0GB) functions.
#!/usr/bin/env php
<?php
declare(ticks=1);
bcscale(3);
// Read a file and process it in chunks.
$infile = "/dev/sde";
$outfile = "/media/recover/MacMini-whole-sparse.img";
$blksz = 4096;
$blkct = 19537686;
$blkct_b = bcmul($blkct, $blksz, 0);
function ksep($number) {
$number = (string) $number;
$max = strlen($number);
$recip = $max;
for ($i = 0; $i < $max; ++$i) {
--$recip;
if ($i && !($i % 3))
$out = "," . $out;
$out = $number{$recip} . $out;
}
return $out;
}
function prettyGigs($bytes) {
$powers = " kMGTPEZY";
$power = 0;
$mod = 1;
while (bcdiv($bytes, $mod) > 1024) {
$mod = bcmul($mod, 1024);
++$power;
}
$num = bcdiv($bytes, $mod);
switch (((int) $num != $num)? strpos($num, "."): 0) {
case "0":
$fmt = "%0.0f%s";
break;
case "1":
$fmt = "%0.3f%s";
break;
case "2":
$fmt = "%0.2f%s";
break;
case "3":
default:
$fmt = "%0.1f%s";
break;
}
if ($power)
$power = $powers{$power}."B";
else $power = "B";
return sprintf($fmt, $num, $power);
}
function stats() {
pcntl_alarm(1);
$blksz = $GLOBALS['blksz'];
$blkct = $GLOBALS['blkct'];
$blkct_b = $GLOBALS['blkct_b'];
$data = $GLOBALS['data'];
$data_b = bcmul($data, $blksz, 0);
$sparse = $GLOBALS['sparse'];
$sparse_b = bcmul($sparse, $blksz, 0);
$count = bcadd($GLOBALS['data'], $GLOBALS['sparse'], 0);
$count_b = bcmul($count, $blksz, 0);
$pct = bcmul(bcdiv($count, $GLOBALS['blkct'], 10), 100.0);
$speed = bcmul(bcsub($count, $GLOBALS['old_count']), $blksz);
printf("\rD: %ss (%s) S: %ss (%s) +: %ss (%s) T: %ss (%s) %%: %0.4f %s/sec ",
ksep($data), prettyGigs($data_b), ksep($sparse), prettyGigs($sparse_b), ksep($count), prettyGigs($count_b),
ksep($blkct), prettyGigs($blkct_b), $pct, prettyGigs($speed));
/* printf("\rBlk: %s Spa: %s Sum: %s Tot: %s Pct: %0.4f ",
thousands($GLOBALS['data']), thousands($GLOBALS['sparse']),
thousands($count), thousands($GLOBALS['blkct']), $pct);
*/ $GLOBALS['old_count'] = $count;
}
pcntl_signal(SIGALRM, "stats", true);
pcntl_alarm(1);
echo "\n\nPrecaching...";
/* No longer required
// Precalculate crc
$bufr = str_repeat("\0", 4096);
$zero = crc32($bufr);
*/
$input = fopen($infile, "rb");
$output = fopen($outfile, "wb");
if (!is_resource($input))
die(sprintf("%s failed!\n", $infile));
if (!is_resource($output))
die(sprintf("%s failed!\n", $outfile));
$data = 0;
$sparse = 0;
while (!feof($input)) {
$bufr = fread($input, $blksz);
$chars = count_chars($bufr, 3);
if ($chars === "\0") {
// Nul block. Skip it.
fseek($output, ftell($output) + $blksz);
$sparse++;
continue;
}
/* Counting chars takes roughly half the time as computing the crc32.
if (crc32($bufr) == $zero) {
// Matching block? compare by bytes
$chars = count_chars($bufr, 3);
if ($chars === "\0") {
// Null block. Skip it.
fseek($output, ftell($output) + $blksz);
continue;
}
}
*/ fwrite($output, $bufr, $blksz);
$data++;
}
fclose($input);
fclose($output);
echo "\n\n";
?>
Ruby version:
#!/usr/bin/env ruby
# Fucking kludge.
require 'dl/import'
module Alarm
extend DL::Importable
dlload "libc.so.6"
extern "unsigned int alarm(unsigned int)"
end
# $stdout (standard out) is buffered! $stdout.flush() if you want it to show up immediately!
# Variables:
# * global variables start with $
# * instance variables start with @
# * local variables start with _ or a lowercase
# * constants start with an uppercase.
# Chr to ord: "x"[0] <- Access by index.
# Ord to chr: 120.chr <- Access chr method
# In for, start..end is start through end, while start...end is start up to but not including end.
# $data is, apparently, a reserved word.
$blksz = 4096;
$blkct = 19537686;
$blkct_b = $blkct * $blksz;
src_file = "/dev/sde";
out_file = "/media/recover/MacMini-whole-sparse.img";
src = File.new(src_file);
out = File.new(out_file, File::CREAT|File::TRUNC|File::RDWR, 0600);
#$old_sum_b = 0;
def kSep(kSep_num)
kSep_num = kSep_num.to_s;
max = kSep_num.length;
recip = max;
out = "";
for cur in 0...max
recip-= 1;
if (cur != 0 && (cur % 3) == 0)
out = "," << out;
end
out = kSep_num[recip].chr << out;
end
return out;
end
def pMag(bytes)
bytes = bytes.to_f;
powers = " kMGTPEZY";
power = 0;
fmt = "";
out = "";
mod = 1;
while ((bytes / mod) > 1024)
mod = mod * 1024;
power+= 1;
end
num = bytes / mod;
case (num.to_s.index("."))
when nil then fmt = "%0.0f%s";
when 0 then fmt = "%0.0f%s";
when 1 then fmt = "%0.3f%s";
when 2 then fmt = "%0.2f%s";
when 3 then fmt = "%0.1f%s";
else fmt = "$0.0f%s";
end
out << sprintf(fmt, num, powers[power].chr);
return out;
end
trap("ALRM") do
Alarm.alarm(1);
# Format and display stats all pretty-like
isdata_b = $isdata * $blksz;
issparse_b = $issparse * $blksz;
sum = $isdata + $issparse;
sum_b = sum * $blksz;
pct = (sum.to_f / $blkct) * 100;
perf = sum_b - (@old_sum_b? @old_sum_b: 0);
$stdout.printf("\rD: %ss (%sB) S: %ss (%sB) +: %ss (%sB) T: %ss (%sB) %%: %0.3f%% %sB/sec ",
kSep($isdata), pMag(isdata_b), kSep($issparse), pMag(issparse_b),
kSep(sum), pMag(sum_b), kSep($blkct), pMag($blkct_b), pct, pMag(perf));
@old_sum_b = sum_b;
$stdout.flush();
end
# Control vars
$isdata = 0;
$issparse = 0;
buf = "";
notnull = false;
# Start display loop
Alarm.alarm(1);
$stdout.printf("Precaching...");
$stdout.flush();
# Start processing loop
while (!src.eof?)
buf = src.read($blksz);
# Old byte-scanning section
# notnull = false;
# for byte in 0...$blksz
# if (buf[byte] != 0)
# # Break out of the loop on non-null data
# notnull = true;
# break;
# end
# end
# if (notnull)
# $isdata+= 1;
# out.write(buf);
# else
# $issparse+= 1;
# out.seek($blksz, File::SEEK_CUR);
# end
# New regex section
# !!!! Ruby's regular expressions are different! ^/$ match after/before newlines! Use \A/\Z to match start/end of string!
if (/\A\0+\Z/ =~ buf)
$issparse+= 1;
out.seek($blksz, File::SEEK_CUR);
else
$isdata+= 1;
out.write(buf);
end
end
# Make everything nice and even
out.truncate($blkct * $blksz);
src.close();
out.close();
$stdout.printf("\n\n");
exit(0);