7227f722ac
Reviewed By: zertosh Differential Revision: D38485159 fbshipit-source-id: 0abdf44561da00697953fe2cb9211ceb5cf27ac0
98 lines
3.1 KiB
Rust
98 lines
3.1 KiB
Rust
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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//! Intrinsic hash for a tarball.
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use std::collections;
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use std::io;
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use anyhow::Result;
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use crate::types;
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/// Computes the intrinsic SHA256 checksum of a tar archive.
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pub fn tarsum<R: io::Read>(reader: R) -> Result<types::HashSum> {
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use sha2::Digest;
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let mut archive = tar::Archive::new(reader);
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let mut map = collections::BTreeMap::new();
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// Store all entries in a BTreeMap using their path as key which implements `Ord`.
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// This way we ensure that the hash of hashes is consistent indepent of the
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// file order inside the archive.
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for entry in archive.entries()? {
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let mut e = entry?;
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let path = e.path()?.into_owned();
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map.insert(path.clone(), digest_file(&mut e)?);
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}
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let mut digest = sha2::Sha256::new();
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for (_, file_hash) in map {
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digest.update(file_hash.0);
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}
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let hash = digest.finalize();
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Ok(types::HashSum(data_encoding::HEXLOWER.encode(&hash)))
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}
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fn digest_file<R: io::Read>(reader: &mut R) -> io::Result<types::HashSum> {
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use sha2::Digest;
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let mut digest = sha2::Sha256::new();
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io::copy(reader, &mut digest)?;
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let hash = digest.finalize();
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Ok(types::HashSum(data_encoding::HEXLOWER.encode(&hash)))
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}
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#[cfg(test)]
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mod test {
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use std::fs;
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use std::path;
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use super::*;
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#[test]
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fn test_nested_archive_tarsum() {
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// This is an archive with a nested directory structure.
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let archive_path = path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
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.join("src")
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.join("__fixtures__")
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.join("nested_archive.tar");
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let reader = fs::File::open(archive_path).unwrap();
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let res = tarsum(reader).unwrap();
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assert_eq!(
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res,
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types::HashSum(
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"6f92565bb50b9469494b3e1ad668f5d809caa3ffb534c3e56dec75f7ea7912df".to_string()
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)
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);
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}
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#[test]
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fn test_differently_ordered_archives() {
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// These archives have equivalent contents but were created in reverse ways:
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// $ tar cf archive_a.tar archive/a.txt
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// $ tar cf archive_b.tar archive/b.txt
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// $ tar rf archive_a.tar archive/b.txt
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// $ tar rf archive_b.tar archive/a.txt
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// $ gsha256sum archive_*.tar
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// 8de80c3904d85115d1595d48c215022e5db225c920811d4d2eee80586e6390c8 archive_a.tar
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// 60097b704cb1684f52f7e98e98193595ea2876047e9ecc6931db97757bc8a5fd archive_b.tar
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let fixture_path = path::PathBuf::from(env!("CARGO_MANIFEST_DIR"))
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.join("src")
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.join("__fixtures__");
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let archive_a = fixture_path.join("archive_a.tar");
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let archive_b = fixture_path.join("archive_b.tar");
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let reader_a = fs::File::open(archive_a).unwrap();
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let reader_b = fs::File::open(archive_b).unwrap();
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let res_a = tarsum(reader_a).unwrap();
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let res_b = tarsum(reader_b).unwrap();
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assert_eq!(res_a, res_b);
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}
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}
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