<?php
declare(strict_types=1);
/*
* This file is part of the nelexa/zip package.
* (c) Ne-Lexa <https://github.com/Ne-Lexa/php-zip>
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace PhpZip\Model\Extra\Fields;
use PhpZip\Constants\UnixStat;
use PhpZip\Exception\Crc32Exception;
use PhpZip\Model\Extra\ZipExtraField;
use PhpZip\Model\ZipEntry;
/**
* ASi Unix Extra Field:
* ====================.
*
* The following is the layout of the ASi extra block for Unix. The
* local-header and central-header versions are identical.
* (Last Revision 19960916)
*
* Value Size Description
* ----- ---- -----------
* (Unix3) 0x756e Short tag for this extra block type ("nu")
* TSize Short total data size for this block
* CRC Long CRC-32 of the remaining data
* Mode Short file permissions
* SizDev Long symlink'd size OR major/minor dev num
* UID Short user ID
* GID Short group ID
* (var.) variable symbolic link filename
*
* Mode is the standard Unix st_mode field from struct stat, containing
* user/group/other permissions, setuid/setgid and symlink info, etc.
*
* If Mode indicates that this file is a symbolic link, SizDev is the
* size of the file to which the link points. Otherwise, if the file
* is a device, SizDev contains the standard Unix st_rdev field from
* struct stat (includes the major and minor numbers of the device).
* SizDev is undefined in other cases.
*
* If Mode indicates that the file is a symbolic link, the final field
* will be the name of the file to which the link points. The file-
* name length can be inferred from TSize.
*
* [Note that TSize may incorrectly refer to the data size not counting
* the CRC; i.e., it may be four bytes too small.]
*
* @see ftp://ftp.info-zip.org/pub/infozip/doc/appnote-iz-latest.zip Info-ZIP version Specification
*/
final class AsiExtraField implements ZipExtraField
{
/** @var int Header id */
public const HEADER_ID = 0x756E;
public const USER_GID_PID = 1000;
/** Bits used for permissions (and sticky bit). */
public const PERM_MASK = 07777;
/** @var int Standard Unix stat(2) file mode. */
private int $mode;
/** @var int User ID. */
private int $uid;
/** @var int Group ID. */
private int $gid;
/**
* @var string File this entry points to, if it is a symbolic link.
* Empty string - if entry is not a symbolic link.
*/
private string $link;
public function __construct(int $mode, int $uid = self::USER_GID_PID, int $gid = self::USER_GID_PID, string $link = '')
{
$this->mode = $mode;
$this->uid = $uid;
$this->gid = $gid;
$this->link = $link;
}
/**
* Returns the Header ID (type) of this Extra Field.
* The Header ID is an unsigned short integer (two bytes)
* which must be constant during the life cycle of this object.
*/
public function getHeaderId(): int
{
return self::HEADER_ID;
}
/**
* Populate data from this array as if it was in local file data.
*
* @param string $buffer the buffer to read data from
* @param ZipEntry|null $entry optional zip entry
*
* @throws Crc32Exception
*
* @return AsiExtraField
*/
public static function unpackLocalFileData(string $buffer, ?ZipEntry $entry = null): self
{
$givenChecksum = unpack('V', $buffer)[1];
$buffer = substr($buffer, 4);
$realChecksum = crc32($buffer);
if ($givenChecksum !== $realChecksum) {
throw new Crc32Exception('Asi Unix Extra Filed Data', $givenChecksum, $realChecksum);
}
[
'mode' => $mode,
'linkSize' => $linkSize,
'uid' => $uid,
'gid' => $gid,
] = unpack('vmode/VlinkSize/vuid/vgid', $buffer);
$link = '';
if ($linkSize > 0) {
$link = substr($buffer, 10);
}
return new self($mode, $uid, $gid, $link);
}
/**
* Populate data from this array as if it was in central directory data.
*
* @param string $buffer the buffer to read data from
* @param ZipEntry|null $entry optional zip entry
*
* @throws Crc32Exception
*
* @return AsiExtraField
*/
public static function unpackCentralDirData(string $buffer, ?ZipEntry $entry = null): self
{
return self::unpackLocalFileData($buffer, $entry);
}
/**
* The actual data to put into local file data - without Header-ID
* or length specifier.
*
* @return string the data
*/
public function packLocalFileData(): string
{
$data = pack(
'vVvv',
$this->mode,
\strlen($this->link),
$this->uid,
$this->gid
) . $this->link;
return pack('V', crc32($data)) . $data;
}
/**
* The actual data to put into central directory - without Header-ID or
* length specifier.
*
* @return string the data
*/
public function packCentralDirData(): string
{
return $this->packLocalFileData();
}
/**
* Name of linked file.
*
* @return string name of the file this entry links to if it is a
* symbolic link, the empty string otherwise
*/
public function getLink(): string
{
return $this->link;
}
/**
* Indicate that this entry is a symbolic link to the given filename.
*
* @param string $link name of the file this entry links to, empty
* string if it is not a symbolic link
*/
public function setLink(string $link): void
{
$this->link = $link;
$this->mode = $this->getPermissionsMode($this->mode);
}
/**
* Is this entry a symbolic link?
*
* @return bool true if this is a symbolic link
*/
public function isLink(): bool
{
return !empty($this->link);
}
/**
* Get the file mode for given permissions with the correct file type.
*
* @param int $mode the mode
*
* @return int the type with the mode
*/
private function getPermissionsMode(int $mode): int
{
$type = 0;
if ($this->isLink()) {
$type = UnixStat::UNX_IFLNK;
} elseif (($mode & UnixStat::UNX_IFREG) !== 0) {
$type = UnixStat::UNX_IFREG;
} elseif (($mode & UnixStat::UNX_IFDIR) !== 0) {
$type = UnixStat::UNX_IFDIR;
}
return $type | ($mode & self::PERM_MASK);
}
/**
* Is this entry a directory?
*
* @return bool true if this entry is a directory
*/
public function isDirectory(): bool
{
return ($this->mode & UnixStat::UNX_IFDIR) !== 0 && !$this->isLink();
}
public function getMode(): int
{
return $this->mode;
}
public function setMode(int $mode): void
{
$this->mode = $this->getPermissionsMode($mode);
}
public function getUserId(): int
{
return $this->uid;
}
public function setUserId(int $uid): void
{
$this->uid = $uid;
}
public function getGroupId(): int
{
return $this->gid;
}
public function setGroupId(int $gid): void
{
$this->gid = $gid;
}
public function __toString(): string
{
return sprintf(
'0x%04x ASI: Mode=%o UID=%d GID=%d Link="%s',
self::HEADER_ID,
$this->mode,
$this->uid,
$this->gid,
$this->link
);
}
}