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libphutil/scripts/sandpit/harden_directory.php
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harden_directory.php
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#!/usr/bin/env php
<?php
require_once dirname(__FILE__).'/../__init_script__.php';
if ($argc !== 4) {
usage();
exit(1);
}
function usage() {
echo phutil_console_format(<<<EOUSAGE
usage: harden_directory.php soft_directory link scratch_dir
Massively reduce the disk usage of a readonly directory by using hardlinks to
represent its data. Pass a normal __soft_directory__ to compress, and a
__link__ to symlink to the compressed version once compression is complete.
The directory will be cloned into __scratch_dir__ and replaced with hardlinks.
This is primarily useful if you want to have checkouts of hundreds of different
commits in a version-controlled repository, so you can, e.g., run unit tests or
other readonly processes on them.
EOUSAGE
);
}
$soft = Filesystem::resolvePath($argv[1]);
$dst = $argv[2];
$root = Filesystem::resolvePath($argv[3]);
$hash_map = map_directory($soft);
$hardened_id = sha1(Filesystem::readRandomBytes(128));
$hardened_id = hash_path($hardened_id);
$hardened = $root.'/pit/'.$hardened_id;
execx('mkdir -p %s', $hardened);
$obj_root = $root.'/obj/';
foreach ($hash_map as $path => $info) {
$hash = $info['hash'];
$type = $info['type'];
$obj = $obj_root.hash_path($hash);
$link = $hardened.'/'.$path;
$dir = dirname($link);
if (!is_dir($dir)) {
$ok = mkdir($dir, 0777, $recursive = true);
if (!$ok) {
throw new Exception(pht("Failed to make directory for '%s'!", $link));
}
}
// We need to use actual symlinks in this case.
if ($type == 'link') {
$ok = symlink(readlink($soft.'/'.$path), $link);
if (!$ok) {
throw new Exception(pht("Failed to create symlink '%s'!", $link));
}
continue;
}
if ($type === 'exec') {
// Multiple hardlinks share a single executable bit, so we need to keep
// executable versions separate from non-executable versions.
$obj .= '.x';
}
// Make copies of each object, obj.0, obj.1, etc., after there are too many
// hardlinks. This can occur for the empty file, particularly.
$n = 0;
do {
$stat = @lstat($obj.'.'.$n);
if (!$stat) {
break;
}
if ($stat[3] < 32000) {
// TODO: On NTFS, this needs to be 1023. It is not apparently trivial to
// determine if a disk is NTFS or not, or what the link limit for a disk
// is. On linux "df -T /path/to/dir" may be useful, but on OS X this does
// something totally different...
break;
}
++$n;
} while (true);
$obj = $obj.'.'.$n;
if ($stat === false) {
$ok = mkdir(dirname($obj), 0777, $recursive = true);
if (!$ok) {
throw new Exception(pht("Failed to make directory for '%s'.", $obj));
}
$ok = copy($soft.'/'.$path, $obj);
if (!$ok) {
throw new Exception(pht("Failed to copy file '%s/%s'!", $soft, $path));
}
if ($type === 'exec') {
$ok = chmod($obj, 0755);
if (!$ok) {
throw new Exception(pht("Failed to chmod file '%s'!", $obj));
}
}
}
$ok = link($obj, $link);
if (!$ok) {
throw new Exception(pht("Failed to hardlink '%s' to '%s'!", $obj, $link));
}
}
// TODO: Replace link to soft directory with link to hardened directory.
// execx('ln -sf %s %s', $dst, $hardened);
echo $hardened."\n";
exit(0);
function hash_path($hash) {
return preg_replace('/([a-z0-9]{2})/', '\1/', $hash, 3);
}
function map_directory($dir) {
try {
if (Filesystem::pathExists($dir.'/.git')) {
list($list) = execx(
'(cd %s && git ls-tree -r --full-tree --abbrev=40 HEAD)',
$dir);
$list = trim($list);
$list = explode("\n", $list);
$map = array();
foreach ($list as $line) {
$matches = null;
$regexp = '/^(\d{6}) (\w+) ([a-z0-9]{40})\t(.*)$/';
if (!preg_match($regexp, $line, $matches)) {
throw new Exception(pht("Unable to parse line '%s'!", $line));
}
$flag = $matches[1];
$type = $matches[2];
$hash = $matches[3];
$file = $matches[4];
if ($type === 'commit') {
// Deal with Git submodules.
$submap = map_directory($dir.'/'.$file);
foreach ($submap as $subfile => $info) {
$map[$file.'/'.$subfile] = $info;
}
} else {
$mask = (int)base_convert($flag, 8, 10);
$type = 'file';
if ($mask & 0111) {
echo pht('EXEC: %s', $file)."\n";
$type = 'exec';
} else if (($mask & 0120000) === 0120000) {
$type = 'link';
}
$map[$file] = array(
'hash' => $hash,
'type' => $type,
);
}
}
return $map;
}
} catch (Exception $ex) {
phlog($ex);
// Just drop down and go with the non-git approach.
}
$files = id(new FileFinder($dir))
->withType('f')
->excludePath('*/.git/*')
->excludePath('*/.svn/*')
->find();
foreach ($files as $file) {
if (!strncmp($file, './', 2)) {
$file = substr($file, 2);
}
$data = Filesystem::readFile($dir.'/'.$file);
$len = strlen($data);
$hash = sha1("blob {$len}\0{$data}");
$type = 'file';
if (is_link($dir.'/'.$file)) {
$type = 'link';
} else if (is_executable($dir.'/'.$file)) {
$type = 'exec';
}
$map[$file] = array(
'hash' => $hash,
'type' => $type,
);
}
return $map;
}
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