/**
* Read the header from the file.
*
* @return void
*
* @throws \RuntimeException When the manifest is larger than 100MB (hardcoded limit in PHP).
*
* @throws \UnexpectedValueException When the manifest header is truncated.
*
* @throws \RuntimeException When the API version is not understood.
*
* @throws \UnexpectedValueException When the file length is smaller than the offset of the file contents.
*/
private function readHead()
{
$this->detectStub();
// Check header.
$manifestLength = $this->file->readUint32le();
if ($manifestLength > 1048576 * 100) {
// Prevent serious memory issues by limiting manifest to at most 100 MB in length.
// See also: https://github.com/php/php-src/blob/12ff95/ext/phar/phar.c#L719
throw new \RuntimeException('manifest cannot be larger than 100 MB');
}
$this->file->savePosition();
if ($manifestLength < 10 || $manifestLength != strlen($this->file->read($manifestLength))) {
throw new \UnexpectedValueException('internal corruption of phar (truncated manifest header)');
}
// Back to where we took off.
$this->file->loadPosition();
$this->numFiles = $this->file->readUint32le();
$apiVersion = $this->file->readUint16be();
if (($apiVersion & 0xfff0) > self::MAX_API_VERSION) {
throw new \RuntimeException(sprintf('Unable to process phar file, unsupported API version ', $apiVersion >> 12, $apiVersion >> 8 & 0xf, $apiVersion >> 4 & 0xf));
}
$this->phar->setApiVersion($apiVersion);
$this->phar->setFlags($this->file->readUint32le());
if (0 < ($aliasLength = $this->file->readUint32le())) {
$this->phar->setAlias($this->file->read($aliasLength));
}
if (0 < ($metadataLength = $this->file->readUint32le())) {
$this->phar->setMetadata(unserialize($this->file->read($metadataLength)));
}
$this->binOffset = strlen($this->phar->getStub()) + $manifestLength + 4;
if ($this->file->getLength() < $this->binOffset) {
throw new \UnexpectedValueException('internal corruption of phar (truncated manifest header)');
}
}
