From 8dfd8bce0484616c3f7b11d2846d95dddc154c1f Mon Sep 17 00:00:00 2001 From: Florian Klink Date: Fri, 27 Oct 2023 22:18:31 +0300 Subject: refactor(tvix/nix-compat/narinfo): return errors This provides more info about where a NARInfo failed to parse, rather than just returning None and leaving a library user to manually debug. Change-Id: I9a28ddd8e5712101483ebe686fdc474c7bbc8e4e Reviewed-on: https://cl.tvl.fyi/c/depot/+/9831 Tested-by: BuildkiteCI Reviewed-by: edef --- tvix/nix-compat/src/narinfo.rs | 172 ++++++++++++++++++++++++++++++----------- 1 file changed, 127 insertions(+), 45 deletions(-) (limited to 'tvix') diff --git a/tvix/nix-compat/src/narinfo.rs b/tvix/nix-compat/src/narinfo.rs index a66709abfe79..b22415218592 100644 --- a/tvix/nix-compat/src/narinfo.rs +++ b/tvix/nix-compat/src/narinfo.rs @@ -63,7 +63,7 @@ pub struct NarInfo<'a> { } impl<'a> NarInfo<'a> { - pub fn parse(input: &'a str) -> Option { + pub fn parse(input: &'a str) -> Result { let mut store_path = None; let mut url = None; let mut compression = None; @@ -78,117 +78,142 @@ impl<'a> NarInfo<'a> { let mut ca = None; for line in input.lines() { - let (tag, val) = line.split_once(':')?; - let val = val.strip_prefix(' ')?; + let (tag, val) = line + .split_once(':') + .ok_or(Error::InvalidLine(line.to_string()))?; + + let val = val + .strip_prefix(' ') + .ok_or(Error::InvalidLine(line.to_string()))?; match tag { "StorePath" => { - let val = val.strip_prefix("/nix/store/")?; - let val = StorePathRef::from_bytes(val.as_bytes()).ok()?; + let val = val + .strip_prefix("/nix/store/") + .ok_or(Error::InvalidStorePath( + crate::store_path::Error::MissingStoreDir, + ))?; + let val = StorePathRef::from_bytes(val.as_bytes()) + .map_err(Error::InvalidStorePath)?; if store_path.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "URL" => { if val.is_empty() { - return None; + return Err(Error::EmptyField(tag.to_string())); } if url.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "Compression" => { if val.is_empty() { - return None; + return Err(Error::EmptyField(tag.to_string())); } if compression.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "FileHash" => { - let val = val.strip_prefix("sha256:")?; - let val = nixbase32::decode_fixed::<32>(val).ok()?; + let val = val + .strip_prefix("sha256:") + .ok_or(Error::MissingPrefixForHash(tag.to_string()))?; + let val = nixbase32::decode_fixed::<32>(val) + .map_err(|e| Error::UnableToDecodeHash(tag.to_string(), e))?; if file_hash.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "FileSize" => { - let val = val.parse::().ok()?; + let val = val + .parse::() + .map_err(|_| Error::UnableToParseSize(tag.to_string(), val.to_string()))?; if file_size.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "NarHash" => { - let val = val.strip_prefix("sha256:")?; - let val = nixbase32::decode_fixed::<32>(val).ok()?; + let val = val + .strip_prefix("sha256:") + .ok_or(Error::MissingPrefixForHash(tag.to_string()))?; + + let val = nixbase32::decode_fixed::<32>(val) + .map_err(|e| Error::UnableToDecodeHash(tag.to_string(), e))?; if nar_hash.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "NarSize" => { - let val = val.parse::().ok()?; + let val = val + .parse::() + .map_err(|_| Error::UnableToParseSize(tag.to_string(), val.to_string()))?; if nar_size.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "References" => { let val: Vec = if !val.is_empty() { let mut prev = ""; val.split(' ') - .map(|s| { + .enumerate() + .map(|(i, s)| { if mem::replace(&mut prev, s) < s { - StorePathRef::from_bytes(s.as_bytes()).ok() + StorePathRef::from_bytes(s.as_bytes()) + .map_err(|err| Error::InvalidReference(i, err)) } else { // references are out of order - None + Err(Error::OutOfOrderReference(i)) } }) - .collect::>()? + .collect::>()? } else { vec![] }; if references.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "System" => { if val.is_empty() { - return None; + return Err(Error::EmptyField(tag.to_string())); } if system.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "Deriver" => { - let val = StorePathRef::from_bytes(val.as_bytes()).ok()?; + let val = StorePathRef::from_bytes(val.as_bytes()) + .map_err(Error::InvalidDeriverStorePath)?; if !val.name().ends_with(".drv") { - return None; + return Err(Error::InvalidDeriverStorePathMissingSuffix); } if deriver.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } "Sig" => { - let val = Signature::parse(val)?; + let val = Signature::parse(val) + .map_err(|e| Error::UnableToParseSignature(signatures.len(), e))?; signatures.push(val); } "CA" => { - let val = parse_ca(val)?; + let val = parse_ca(val).ok_or(Error::UnableToParseCA(val.to_string()))?; if ca.replace(val).is_some() { - return None; + return Err(Error::DuplicateField(tag.to_string())); } } _ => { @@ -197,16 +222,16 @@ impl<'a> NarInfo<'a> { } } - Some(NarInfo { - store_path: store_path?, - nar_hash: nar_hash?, - nar_size: nar_size?, - references: references?, + Ok(NarInfo { + store_path: store_path.ok_or(Error::MissingField("StorePath".to_string()))?, + nar_hash: nar_hash.ok_or(Error::MissingField("NarHash".to_string()))?, + nar_size: nar_size.ok_or(Error::MissingField("NarSize".to_string()))?, + references: references.ok_or(Error::MissingField("References".to_string()))?, signatures, ca, system, deriver, - url: url?, + url: url.ok_or(Error::MissingField("URL".to_string()))?, compression, file_hash, file_size, @@ -271,8 +296,10 @@ pub struct Signature<'a> { } impl<'a> Signature<'a> { - pub fn parse(input: &'a str) -> Option> { - let (name, bytes64) = input.split_once(':')?; + pub fn parse(input: &'a str) -> Result, SignatureError> { + let (name, bytes64) = input + .split_once(':') + .ok_or(SignatureError::MissingSeparator)?; let mut buf = [0; 66]; let mut bytes = [0; 64]; @@ -280,12 +307,12 @@ impl<'a> Signature<'a> { Ok(64) => { bytes.copy_from_slice(&buf[..64]); } - _ => { - return None; - } + Ok(n) => return Err(SignatureError::InvalidSignatureLen(n)), + // keeping DecodePartial gets annoying lifetime-wise + Err(_) => return Err(SignatureError::DecodeError(input.to_string())), } - Some(Signature { name, bytes }) + Ok(Signature { name, bytes }) } pub fn name(&self) -> &'a str { @@ -297,6 +324,16 @@ impl<'a> Signature<'a> { } } +#[derive(Debug, thiserror::Error)] +pub enum SignatureError { + #[error("Missing separator")] + MissingSeparator, + #[error("Invalid signature len: {0}")] + InvalidSignatureLen(usize), + #[error("Unable to base64-decode signature: {0}")] + DecodeError(String), +} + impl Display for Signature<'_> { fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result { write!(w, "{}:{}", self.name, BASE64.encode(&self.bytes)) @@ -374,6 +411,51 @@ impl Display for fmt_hash<'_> { } } +#[derive(thiserror::Error, Debug)] +pub enum Error { + #[error("duplicate field: {0}")] + DuplicateField(String), + + #[error("missing field: {0}")] + MissingField(String), + + #[error("invalid line: {0}")] + InvalidLine(String), + + #[error("invalid StorePath: {0}")] + InvalidStorePath(crate::store_path::Error), + + #[error("field {0} may not be empty string")] + EmptyField(String), + + #[error("invalid {0}: {1}")] + UnableToParseSize(String, String), + + #[error("unable to parse #{0} reference: {1}")] + InvalidReference(usize, crate::store_path::Error), + + #[error("reference at {0} is out of order")] + OutOfOrderReference(usize), + + #[error("invalid Deriver store path: {0}")] + InvalidDeriverStorePath(crate::store_path::Error), + + #[error("invalid Deriver store path, must end with .drv")] + InvalidDeriverStorePathMissingSuffix, + + #[error("missing prefix for {0}")] + MissingPrefixForHash(String), + + #[error("unable to decode {0}: {1}")] + UnableToDecodeHash(String, nixbase32::Nixbase32DecodeError), + + #[error("unable to parse signature #{0}: {1}")] + UnableToParseSignature(usize, SignatureError), + + #[error("unable to parse CA field: {0}")] + UnableToParseCA(String), +} + #[cfg(test)] mod test { use lazy_static::lazy_static; -- cgit 1.4.1