// TODO: make this no_std if possible
use camino::Utf8PathBuf;
mod hbm;
pub use hbm::HalfBytesMask;
mod spec;
pub use spec::*;
/// limit maximal length of store basename
const BASENAME_MAXLEN: usize = 255;
/// this is a trait which implements the interface of possible inputs
/// (usually byte slices)
pub trait ScannerInput: AsRef<[u8]> + Sized {
/// Splits the input into two at the given index.
/// Afterwards self contains elements [at, len), and the returned input part contains elements [0, at).
fn split_to(&mut self, at: usize) -> Self;
fn finish(&mut self);
}
impl ScannerInput for &[u8] {
fn split_to(&mut self, at: usize) -> Self {
let (a, b) = self.split_at(at);
*self = b;
a
}
fn finish(&mut self) {
*self = &[];
}
}
impl ScannerInput for &mut [u8] {
fn split_to(&mut self, at: usize) -> Self {
// Lifetime dance taken from `impl Write for &mut [u8]`.
// Taken from crate `std`.
let (a, b) = core::mem::replace(self, &mut []).split_at_mut(at);
*self = b;
a
}
fn finish(&mut self) {
*self = &mut [];
}
}
/// this is the primary structure of this crate
///
/// it represents a scanner which scans binary slices for store references,
/// and implements an iterator interfaces which returns these as byte slices.
pub struct StoreRefScanner<'x, Input: 'x> {
input: Input,
spec: &'x StoreSpec,
}
/// Taken from crate `yz-string-utils`.
fn get_offset_of<T>(whole_buffer: &T, part: &T) -> usize
where
T: AsRef<[u8]> + ?Sized,
{
// NOTE: originally I wanted to use offset_from() here once it's stable,
// but according to https://github.com/rust-lang/rust/issues/41079#issuecomment-657163887
// this would be UB in cases where the code below isn't.
part.as_ref().as_ptr() as usize - whole_buffer.as_ref().as_ptr() as usize
}
impl<'x, Input> StoreRefScanner<'x, Input>
where
Input: ScannerInput + 'x,
{
pub fn new(input: Input, spec: &'x StoreSpec) -> Self {
for i in [&spec.valid_hashbytes, &spec.valid_restbytes] {
for j in [b'\0', b' ', b'\t', b'\n', b'/', b'\\'] {
assert!(!i.contains(j));
}
}
Self { input, spec }
}
}
impl<'x, Input: 'x> Iterator for StoreRefScanner<'x, Input>
where
Input: ScannerInput + 'x,
{
type Item = Input;
fn next(&mut self) -> Option<Input> {
let empty_path = camino::Utf8Path::new("");
let hbl: usize = self.spec.hashbytes_len.into();
while !self.input.as_ref().is_empty() {
if self.spec.path_to_store != empty_path {
let p2sas = self.spec.path_to_store.as_str();
if self.input.as_ref().starts_with(p2sas.as_bytes()) {
self.input.split_to(p2sas.len());
} else {
self.input.split_to(1);
continue;
}
}
let hsep = matches!(self.input.as_ref().iter().next(), Some(b'/') | Some(b'\\'));
self.input.split_to(1);
if hsep && self.spec.check_rest(self.input.as_ref()) {
// we have found a valid hash
// rest contains the store basename and all following components
// now let's search for the end
// and then cut off possible following components after the basename
let rlen = self
.input
.as_ref()
.iter()
.enumerate()
.take(BASENAME_MAXLEN)
.skip(hbl)
.find(|&(_, &i)| !self.spec.valid_restbytes.contains(i))
.map(|(eosp, _)| eosp)
.unwrap_or(core::cmp::min(BASENAME_MAXLEN, self.input.as_ref().len()));
return Some(self.input.split_to(rlen));
}
}
self.input.finish();
None
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn simple_nix2() {
let drv: &[u8] = br#"
Derive([("out","","r:sha256","")],[("/nix/store/2ax7bvjdfkzim69q957i0jlg0nvmapg0-util-linux-2.37.2.drv",["dev"]),("/nix/store/6b55ssmh8pzqsc4q4kw1yl3kqvr4fvqj-bash-5.1-p12.drv",["out"]),("/nix/store/fp2vx24kczlzv84avds28wyzsmrn8kyv-source.drv",["out"]),("/nix/store/s6c2lm5hpsvdwnxq9y1g3ngncghjzc3k-stdenv-linux.drv",["out"]),("/nix/store/xlnzpf4mzghi8vl0krabrgcbnqk5qjf3-pkg-config-wrapper-0.29.2.drv",["out"])],["/nix/store/03sl46khd8gmjpsad7223m32ma965vy9-fix-static.patch","/nix/store/2q3z7587yhlz0i2xvfvvap42zk5carlv-bcache-udev-modern.patch","/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],"x86_64-linux","/0g15yibzzi3rmw29gqlbms05x9dbghbvh61v1qggydvmzh3bginw/bin/bash",["-e","/nix/store/9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh"],[("buildInputs","/0sdk1r4l43yw4g6lmqdhd92vhdfhlwz3m76jxzvzsqsv63czw2km"),("builder","/0g15yibzzi3rmw29gqlbms05x9dbghbvh61v1qggydvmzh3bginw/bin/bash"),("configureFlags",""),("depsBuildBuild",""),("depsBuildBuildPropagated",""),("depsBuildTarget",""),("depsBuildTargetPropagated",""),("depsHostHost",""),("depsHostHostPropagated",""),("depsTargetTarget",""),("depsTargetTargetPropagated",""),("doCheck",""),("doInstallCheck",""),("makeFlags","PREFIX=/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9 UDEVLIBDIR=/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9/lib/udev/"),("name","bcache-tools-1.0.7"),("nativeBuildInputs","/1kw0rwgdyq9q69wmmsa5d2kap6p52b0yldbzi4w17bhcq5g5cp2f"),("out","/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9"),("outputHashAlgo","sha256"),("outputHashMode","recursive"),("outputs","out"),("patches","/nix/store/2q3z7587yhlz0i2xvfvvap42zk5carlv-bcache-udev-modern.patch /nix/store/03sl46khd8gmjpsad7223m32ma965vy9-fix-static.patch"),("pname","bcache-tools"),("preBuild","sed -e \"s|/bin/sh|/0g15yibzzi3rmw29gqlbms05x9dbghbvh61v1qggydvmzh3bginw/bin/sh|\" -i *.rules\n"),("preInstall","mkdir -p \"$out/sbin\" \"$out/lib/udev/rules.d\" \"$out/share/man/man8\"\n"),("prePatch","sed -e \"/INSTALL.*initramfs\\/hook/d\" \\\n -e \"/INSTALL.*initcpio\\/install/d\" \\\n -e \"/INSTALL.*dracut\\/module-setup.sh/d\" \\\n -e \"s/pkg-config/$PKG_CONFIG/\" \\\n -i Makefile\n"),("propagatedBuildInputs",""),("propagatedNativeBuildInputs",""),("src","/nix/store/6izcafvfcbz19chi7hl20834g0fa043n-source"),("stdenv","/01ncyv8bxibj0imgfvmxgqy648n697bachil6aw6i46g1jk0bbds"),("strictDeps",""),("system","x86_64-linux"),("version","1.0.7")])
"#;
// we convert everything into strings because it is way easier to compare elements in error messages
let refs: Vec<&str> = StoreRefScanner::new(drv, &*SPEC_DFL_NIX2)
.map(|i| core::str::from_utf8(i).unwrap())
.collect();
let refs_expect: Vec<&[u8]> = vec![
b"2ax7bvjdfkzim69q957i0jlg0nvmapg0-util-linux-2.37.2.drv",
b"6b55ssmh8pzqsc4q4kw1yl3kqvr4fvqj-bash-5.1-p12.drv",
b"fp2vx24kczlzv84avds28wyzsmrn8kyv-source.drv",
b"s6c2lm5hpsvdwnxq9y1g3ngncghjzc3k-stdenv-linux.drv",
b"xlnzpf4mzghi8vl0krabrgcbnqk5qjf3-pkg-config-wrapper-0.29.2.drv",
b"03sl46khd8gmjpsad7223m32ma965vy9-fix-static.patch",
b"2q3z7587yhlz0i2xvfvvap42zk5carlv-bcache-udev-modern.patch",
b"9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh",
b"9krlzvny65gdc8s7kpb6lkx8cd02c25b-default-builder.sh",
b"2q3z7587yhlz0i2xvfvvap42zk5carlv-bcache-udev-modern.patch",
b"03sl46khd8gmjpsad7223m32ma965vy9-fix-static.patch",
b"6izcafvfcbz19chi7hl20834g0fa043n-source",
];
let refs_expect: Vec<&str> = refs_expect
.into_iter()
.map(|i| core::str::from_utf8(i).unwrap())
.collect();
assert_eq!(refs, refs_expect);
}
#[test]
fn simple_yzix1() {
// I haven't yet produced any yzix derivation which included /yzixs absolute paths...
let fake: &[u8] = br#"
/yzixs/4Zx1PBoft1YyAuKdhjAY1seZFHloxQ+8voHQRkRMuys: ASCII text
/yzixs/dNE3yogD4JHKHzNa2t3jQMZddT8wjqlMDB0naDIFo0A: ASCII text
/yzixs/FMluSVOHLc4bxX7F4lBCXafNljBnDn+rAM5HzG7k8LI: unified diff output, ASCII text
/yzixs/g2G3GRL87hGEdw9cq2BZWqDQP_HeHSPRLbJ9P9KH+HI: unified diff output, ASCII text
/yzixs/H08Av1ZAONwFdzVLpFQm0Sc0dvyk0sbnk82waoBig7I: ASCII text
/yzixs/IndARQp+gaGDLS3K+PeyXdaRqAcCyS3EIbRXkkYjC94: unified diff output, ASCII text
/yzixs/IrLPnbkEolTAuWRxkXpuvVs6Imb1iB6wUJcI+fxWwkU: POSIX shell script, ASCII text executable
/yzixs/JsS_H3n3TSh2R6fiIzgOPZdjSmRkV71vGxstJJKPmr4: unified diff output, ASCII text
/yzixs/LZ6pQh1x8DRxZ2IYzetBRS4LuE__IXFjpOfQPxHVwpw: unified diff output, ASCII text
/yzixs/mEi2RPep9daRs0JUvwt1JsDfgYSph5sH_+_ihwn8IGQ: ASCII text
/yzixs/nd4DyljinP3auDMHL_LrpsRJkWQpSHQK2jqtyyzWcBA: POSIX shell script, ASCII text executable
/yzixs/nzpaknF0_ONSHtd0i_e1E3pkLF1QPeJQhAB7x9Ogo_M: unified diff output, ASCII text
/yzixs/UZ3uzVUUMC1gKGLw6tg_aLFwoFrJedXB3xbhEgQOaiY: unified diff output, ASCII text
/yzixs/VKyXxKTXsDGxYJ24YgbvCc1bZkA5twp3TC+Gbi4Kwd8: unified diff output, ASCII text
/yzixs/VPJMl8O1xkc1LsJznpoQrCrQO0Iy+ODCPsgoUBLiRZc: unified diff output, ASCII text
/yzixs/W6r1ow001ASHRj+gtRfyj9Fb_gCO_pBztX8WhYXVdIc: unified diff output, ASCII text
/yzixs/xvwEcXIob_rQynUEtQiQbwaDXEobTVKEGaBMir9oH9k: unified diff output, ASCII text
/yzixs/ZPvQbRJrtyeSITvW3FUZvw99hhNOO3CFqGgmWgScxcg: ASCII text
"#;
let refs: Vec<&str> = StoreRefScanner::new(fake, &*SPEC_DFL_YZIX1)
.map(|i| core::str::from_utf8(i).unwrap())
.collect();
let refs_expect: Vec<&[u8]> = vec![
b"4Zx1PBoft1YyAuKdhjAY1seZFHloxQ+8voHQRkRMuys",
b"dNE3yogD4JHKHzNa2t3jQMZddT8wjqlMDB0naDIFo0A",
b"FMluSVOHLc4bxX7F4lBCXafNljBnDn+rAM5HzG7k8LI",
b"g2G3GRL87hGEdw9cq2BZWqDQP_HeHSPRLbJ9P9KH+HI",
b"H08Av1ZAONwFdzVLpFQm0Sc0dvyk0sbnk82waoBig7I",
b"IndARQp+gaGDLS3K+PeyXdaRqAcCyS3EIbRXkkYjC94",
b"IrLPnbkEolTAuWRxkXpuvVs6Imb1iB6wUJcI+fxWwkU",
b"JsS_H3n3TSh2R6fiIzgOPZdjSmRkV71vGxstJJKPmr4",
b"LZ6pQh1x8DRxZ2IYzetBRS4LuE__IXFjpOfQPxHVwpw",
b"mEi2RPep9daRs0JUvwt1JsDfgYSph5sH_+_ihwn8IGQ",
b"nd4DyljinP3auDMHL_LrpsRJkWQpSHQK2jqtyyzWcBA",
b"nzpaknF0_ONSHtd0i_e1E3pkLF1QPeJQhAB7x9Ogo_M",
b"UZ3uzVUUMC1gKGLw6tg_aLFwoFrJedXB3xbhEgQOaiY",
b"VKyXxKTXsDGxYJ24YgbvCc1bZkA5twp3TC+Gbi4Kwd8",
b"VPJMl8O1xkc1LsJznpoQrCrQO0Iy+ODCPsgoUBLiRZc",
b"W6r1ow001ASHRj+gtRfyj9Fb_gCO_pBztX8WhYXVdIc",
b"xvwEcXIob_rQynUEtQiQbwaDXEobTVKEGaBMir9oH9k",
b"ZPvQbRJrtyeSITvW3FUZvw99hhNOO3CFqGgmWgScxcg",
];
let refs_expect: Vec<&str> = refs_expect
.into_iter()
.map(|i| core::str::from_utf8(i).unwrap())
.collect();
assert_eq!(refs, refs_expect);
}
proptest::proptest! {
#[test]
fn nocrash_nix2(s: Vec<u8>) {
let _ = StoreRefScanner::new(&s[..], &*SPEC_DFL_NIX2).count();
}
#[test]
fn nocrash_yzix1(s: Vec<u8>) {
let _ = StoreRefScanner::new(&s[..], &*SPEC_DFL_YZIX1).count();
}
}
}
