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Diffstat (limited to 'tvix/nix-compat/src/derivation/derivation.rs')
| -rw-r--r-- | tvix/nix-compat/src/derivation/derivation.rs | 347 |
1 files changed, 0 insertions, 347 deletions
diff --git a/tvix/nix-compat/src/derivation/derivation.rs b/tvix/nix-compat/src/derivation/derivation.rs deleted file mode 100644 index c9a45d9c9bd2..000000000000 --- a/tvix/nix-compat/src/derivation/derivation.rs +++ /dev/null @@ -1,347 +0,0 @@ -use crate::derivation::output::{Hash, Output}; -use crate::derivation::write; -use crate::derivation::DerivationError; -use crate::nixbase32; -use crate::store_path::{StorePath, STORE_DIR}; -use serde::{Deserialize, Serialize}; -use sha2::{Digest, Sha256}; -use std::collections::BTreeSet; -use std::{collections::BTreeMap, fmt, fmt::Write}; - -#[derive(Clone, Debug, Default, Eq, PartialEq, Serialize, Deserialize)] -pub struct Derivation { - #[serde(rename = "args")] - pub arguments: Vec<String>, - - pub builder: String, - - #[serde(rename = "env")] - pub environment: BTreeMap<String, String>, - - #[serde(rename = "inputDrvs")] - pub input_derivations: BTreeMap<String, BTreeSet<String>>, - - #[serde(rename = "inputSrcs")] - pub input_sources: BTreeSet<String>, - - pub outputs: BTreeMap<String, Output>, - - pub system: String, -} - -/// compress_hash takes an arbitrarily long sequence of bytes (usually -/// a hash digest), and returns a sequence of bytes of length -/// output_size. -/// -/// It's calculated by rotating through the bytes in the output buffer -/// (zero- initialized), and XOR'ing with each byte of the passed -/// input. It consumes 1 byte at a time, and XOR's it with the current -/// value in the output buffer. -/// -/// This mimics equivalent functionality in C++ Nix. -fn compress_hash(input: &[u8], output_size: usize) -> Vec<u8> { - let mut output: Vec<u8> = vec![0; output_size]; - - for (ii, ch) in input.iter().enumerate() { - output[ii % output_size] ^= ch; - } - - output -} - -/// This returns a store path, either of a derivation or a regular output. -/// The string is hashed with sha256, its digest is compressed to 20 bytes, and -/// nixbase32-encoded (32 characters) -fn build_store_path( - is_derivation: bool, - fingerprint: &str, - name: &str, -) -> Result<StorePath, DerivationError> { - let digest = { - let mut hasher = Sha256::new(); - hasher.update(fingerprint); - hasher.finalize() - }; - let compressed = compress_hash(&digest, 20); - if is_derivation { - StorePath::from_string(format!("{}-{}.drv", nixbase32::encode(&compressed), name).as_str()) - } else { - StorePath::from_string(format!("{}-{}", nixbase32::encode(&compressed), name,).as_str()) - } - .map_err(|_e| DerivationError::InvalidOutputName(name.to_string())) - // Constructing the StorePath can only fail if the passed output name was - // invalid, so map errors to a [DerivationError::InvalidOutputName]. -} - -/// Build a store path for a literal text file in the store that may -/// contain references. -pub fn path_with_references<S: AsRef<str>, I: IntoIterator<Item = S>, C: AsRef<[u8]>>( - name: &str, - content: C, - references: I, -) -> Result<StorePath, DerivationError> { - let mut s = String::from("text"); - - for reference in references { - s.push(':'); - s.push_str(reference.as_ref()); - } - - let content_digest = { - let mut hasher = Sha256::new(); - hasher.update(content); - hasher.finalize() - }; - - s.push_str(&format!( - ":sha256:{:x}:{}:{}", - content_digest, STORE_DIR, name - )); - - build_store_path(false, &s, name) -} - -impl Derivation { - pub fn serialize(&self, writer: &mut impl Write) -> Result<(), fmt::Error> { - writer.write_str(write::DERIVATION_PREFIX)?; - writer.write_char(write::PAREN_OPEN)?; - - write::write_outputs(writer, &self.outputs)?; - write::write_input_derivations(writer, &self.input_derivations)?; - write::write_input_sources(writer, &self.input_sources)?; - write::write_system(writer, &self.system)?; - write::write_builder(writer, &self.builder)?; - write::write_arguments(writer, &self.arguments)?; - write::write_enviroment(writer, &self.environment)?; - - writer.write_char(write::PAREN_CLOSE)?; - - Ok(()) - } - - /// Returns the fixed output path and its hash - // (if the Derivation is fixed output), - /// or None if there is no fixed output. - /// This takes some shortcuts in case more than one output exists, as this - /// can't be a valid fixed-output Derivation. - pub fn get_fixed_output(&self) -> Option<(&String, &Hash)> { - if self.outputs.len() != 1 { - return None; - } - - match self.outputs.get("out") { - #[allow(clippy::manual_map)] - Some(out_output) => match &out_output.hash { - Some(out_output_hash) => Some((&out_output.path, out_output_hash)), - // There has to be a hash, otherwise it would not be FOD - None => None, - }, - None => None, - } - } - - /// Returns the drv path of a Derivation struct. - /// - /// The drv path is calculated like this: - /// - Write the fingerprint of the Derivation to the sha256 hash function. - /// This is: `text:`, - /// all d.InputDerivations and d.InputSources (sorted, separated by a `:`), - /// a `:`, - /// a `sha256:`, followed by the sha256 digest of the ATerm representation (hex-encoded) - /// a `:`, - /// the storeDir, followed by a `:`, - /// the name of a derivation, - /// a `.drv`. - /// - Write the .drv A-Term contents to a hash function - /// - Take the digest, run hash.CompressHash(digest, 20) on it. - /// - Encode it with nixbase32 - /// - Use it (and the name) to construct a [StorePath]. - pub fn calculate_derivation_path(&self, name: &str) -> Result<StorePath, DerivationError> { - let mut s = String::from("text:"); - - // collect the list of paths from input_sources and input_derivations - // into a (sorted, guaranteed by BTreeSet) list, and join them by : - let concat_inputs: BTreeSet<String> = { - let mut inputs = self.input_sources.clone(); - let input_derivation_keys: Vec<String> = - self.input_derivations.keys().cloned().collect(); - inputs.extend(input_derivation_keys); - inputs - }; - - for input in concat_inputs { - s.push_str(&input); - s.push(':'); - } - - // calculate the sha256 hash of the ATerm representation, and represent - // it as a hex-encoded string (prefixed with sha256:). - let aterm_digest = { - let mut derivation_hasher = Sha256::new(); - derivation_hasher.update(self.to_string()); - derivation_hasher.finalize() - }; - - s.push_str(&format!( - "sha256:{:x}:{}:{}.drv", - aterm_digest, STORE_DIR, name, - )); - - build_store_path(true, &s, name) - } - - /// Calculate the drv replacement string for a given derivation. - /// - /// This is either called on a struct without output paths populated, - /// to provide the `drv_replacement_str` value for the `calculate_output_paths` - /// function call, or called on a struct with output paths populated, to - /// calculate / cache lookups for calls to fn_get_drv_replacement. - /// - /// `fn_get_drv_replacement` is used to look up the drv replacement strings - /// for input_derivations the Derivation refers to. - pub fn calculate_drv_replacement_str<F>(&self, fn_get_drv_replacement: F) -> String - where - F: Fn(&str) -> String, - { - let mut hasher = Sha256::new(); - let digest = match self.get_fixed_output() { - Some((fixed_output_path, fixed_output_hash)) => { - hasher.update(format!( - "fixed:out:{}:{}:{}", - &fixed_output_hash.algo, &fixed_output_hash.digest, fixed_output_path, - )); - hasher.finalize() - } - None => { - let mut replaced_input_derivations: BTreeMap<String, BTreeSet<String>> = - BTreeMap::new(); - - // For each input_derivation, look up the replacement. - for (drv_path, input_derivation) in &self.input_derivations { - replaced_input_derivations.insert( - fn_get_drv_replacement(drv_path).to_string(), - input_derivation.clone(), - ); - } - - // construct a new derivation struct with these replaced input derivation strings - let replaced_derivation = Derivation { - input_derivations: replaced_input_derivations, - ..self.clone() - }; - - // write the ATerm of that to the hash function - hasher.update(replaced_derivation.to_string()); - - hasher.finalize() - } - }; - - format!("{:x}", digest) - } - - /// This calculates all output paths of a Derivation and updates the struct. - /// It requires the struct to be initially without output paths. - /// This means, self.outputs[$outputName].path needs to be an empty string, - /// and self.environment[$outputName] needs to be an empty string. - /// - /// Output path calculation requires knowledge of "drv replacement - /// strings", and in case of non-fixed-output derivations, also knowledge - /// of "drv replacement" strings (recursively) of all input derivations. - /// - /// We solve this by asking the caller of this function to provide - /// the drv replacement string of the current derivation itself, - /// which is ran on the struct without output paths. - /// - /// This sound terribly ugly, but won't be too much of a concern later on, as - /// naming fixed-output paths once uploaded will be a tvix-store concern, - /// so there's no need to calculate them here anymore. - /// - /// On completion, self.environment[$outputName] and - /// self.outputs[$outputName].path are set to the calculated output path for all - /// outputs. - pub fn calculate_output_paths( - &mut self, - name: &str, - drv_replacement_str: &str, - ) -> Result<(), DerivationError> { - // Check if the Derivation is fixed output, because they cause - // different fingerprints to be hashed. - match self.get_fixed_output() { - None => { - // The fingerprint and hash differs per output - for (output_name, output) in self.outputs.iter_mut() { - // Assert that outputs are not yet populated, to avoid using this function wrongly. - // We don't also go over self.environment, but it's a sufficient - // footgun prevention mechanism. - assert!(output.path.is_empty()); - - // calculate the output_name_path, which is the part of the NixPath after the digest. - let mut output_path_name = name.to_string(); - if output_name != "out" { - output_path_name.push('-'); - output_path_name.push_str(output_name); - } - - let s = &format!( - "output:{}:sha256:{}:{}:{}", - output_name, drv_replacement_str, STORE_DIR, output_path_name, - ); - - let abs_store_path = - build_store_path(false, s, &output_path_name)?.to_absolute_path(); - - output.path = abs_store_path.clone(); - self.environment - .insert(output_name.to_string(), abs_store_path); - } - } - Some((fixed_output_path, fixed_output_hash)) => { - // Assert that outputs are not yet populated, to avoid using this function wrongly. - // We don't also go over self.environment, but it's a sufficient - // footgun prevention mechanism. - assert!(fixed_output_path.is_empty()); - - let s = { - let mut s = String::new(); - // Fixed-output derivation. - // There's two different hashing strategies in place, depending on the value of hash.algo. - // This code is _weird_ but it is what Nix is doing. See: - // https://github.com/NixOS/nix/blob/1385b2007804c8a0370f2a6555045a00e34b07c7/src/libstore/store-api.cc#L178-L196 - if fixed_output_hash.algo == "r:sha256" { - s.push_str(&format!( - "source:sha256:{}", - fixed_output_hash.digest, // nixbase32 - )); - } else { - s.push_str("output:out:sha256:"); - // This is drv_replacement for FOD, with an empty fixed_output_path. - s.push_str(drv_replacement_str); - } - s.push_str(&format!(":{}:{}", STORE_DIR, name)); - s - }; - - let abs_store_path = build_store_path(false, &s, name)?.to_absolute_path(); - - self.outputs.insert( - "out".to_string(), - Output { - path: abs_store_path.clone(), - hash: Some(fixed_output_hash.clone()), - }, - ); - self.environment.insert("out".to_string(), abs_store_path); - } - }; - - Ok(()) - } -} - -impl fmt::Display for Derivation { - /// Formats the Derivation in ATerm representation. - fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { - self.serialize(f) - } -} |