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use crate::Error;
use byteorder::{LittleEndian, ReadBytesExt};
use std::convert::TryFrom;
use std::io::Read;
pub fn parse<R: Read>(input: &mut R) -> Result<(), Error> {
if String::read(input)? != NAR_VERSION_MAGIC {
return Err(Error::BadNarVersionMagic);
}
parse_file(input)
}
const NAR_VERSION_MAGIC: &str = "nix-archive-1";
fn parse_file<R: Read>(input: &mut R) -> Result<(), Error> {
if String::read(input)? != "(" {
return Err(Error::MissingNarOpenTag);
}
if String::read(input)? != "type" {
return Err(Error::MissingNarField);
}
match String::read(input)?.as_ref() {
"regular" => {
let mut executable = false;
let mut tag = String::read(input)?;
if tag == "executable" {
executable = true;
if String::read(input)? != "" {
return Err(Error::BadExecutableField);
}
tag = String::read(input)?;
}
if tag != "contents" {
return Err(Error::MissingNarField);
}
let contents = Vec::<u8>::read(input)?;
if String::read(input)? != ")" {
return Err(Error::MissingNarCloseTag);
}
}
"directory" => loop {
match String::read(input)?.as_ref() {
"entry" => {
if String::read(input)? != "(" {
return Err(Error::MissingNarOpenTag);
}
if String::read(input)? != "name" {
return Err(Error::MissingNarField);
}
let name = String::read(input)?;
if String::read(input)? != "node" {
return Err(Error::MissingNarField);
}
parse_file(input)?;
let tag = String::read(input)?;
if tag != ")" {
return Err(Error::MissingNarCloseTag);
}
}
")" => break,
s => return Err(Error::BadNarField(s.into())),
}
},
"symlink" => {
if String::read(input)? != "target" {
return Err(Error::MissingNarField);
}
let target = String::read(input)?;
if String::read(input)? != ")" {
return Err(Error::MissingNarCloseTag);
}
}
s => return Err(Error::BadNarField(s.into())),
}
Ok(())
}
trait Deserialize: Sized {
fn read<R: Read>(input: &mut R) -> Result<Self, Error>;
}
impl Deserialize for String {
fn read<R: Read>(input: &mut R) -> Result<Self, Error> {
let buf = Deserialize::read(input)?;
Ok(String::from_utf8(buf).map_err(|_| Error::BadNarString)?)
}
}
impl Deserialize for Vec<u8> {
fn read<R: Read>(input: &mut R) -> Result<Self, Error> {
let n: usize = Deserialize::read(input)?;
let mut buf = vec![0; n];
input.read_exact(&mut buf)?;
skip_padding(input, n)?;
Ok(buf)
}
}
fn skip_padding<R: Read>(input: &mut R, len: usize) -> Result<(), Error> {
if len % 8 != 0 {
let mut buf = [0; 8];
let buf = &mut buf[0..8 - (len % 8)];
input.read_exact(buf)?;
if !buf.iter().all(|b| *b == 0) {
return Err(Error::BadNarPadding);
}
}
Ok(())
}
impl Deserialize for u64 {
fn read<R: Read>(input: &mut R) -> Result<Self, Error> {
Ok(input.read_u64::<LittleEndian>()?)
}
}
impl Deserialize for usize {
fn read<R: Read>(input: &mut R) -> Result<Self, Error> {
let n: u64 = Deserialize::read(input)?;
Ok(usize::try_from(n).map_err(|_| Error::NarSizeFieldTooBig)?)
}
}
|
