From cc8c40480a34aa1d233d9a34b505bee16897ef54 Mon Sep 17 00:00:00 2001 From: Edwin Cheng Date: Thu, 4 Mar 2021 10:48:12 +0800 Subject: Print warning if proc-macro built by old rustc --- crates/proc_macro_api/src/version.rs | 131 +++++++++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 crates/proc_macro_api/src/version.rs (limited to 'crates/proc_macro_api/src/version.rs') diff --git a/crates/proc_macro_api/src/version.rs b/crates/proc_macro_api/src/version.rs new file mode 100644 index 000000000..80cd183a0 --- /dev/null +++ b/crates/proc_macro_api/src/version.rs @@ -0,0 +1,131 @@ +//! Reading proc-macro rustc version information from binary data + +use std::{ + fs::File, + io::{self, Read}, + path::Path, +}; + +use memmap::Mmap; +use object::read::{File as BinaryFile, Object, ObjectSection}; +use snap::read::FrameDecoder as SnapDecoder; + +#[derive(Debug)] +pub(crate) struct RustCInfo { + pub(crate) version: (usize, usize, usize), + pub(crate) channel: String, + pub(crate) commit: String, + pub(crate) date: String, +} + +pub(crate) fn read_info(dylib_path: &Path) -> io::Result { + macro_rules! err { + ($e:literal) => { + io::Error::new(io::ErrorKind::InvalidData, $e) + }; + } + + let ver_str = read_version(dylib_path)?; + let mut items = ver_str.split_whitespace(); + let tag = items.next().ok_or(err!("version format error"))?; + if tag != "rustc" { + return Err(err!("version format error (No rustc tag)")); + } + + let version_part = items.next().ok_or(err!("no version string"))?; + let mut version_parts = version_part.split("-"); + let version = version_parts.next().ok_or(err!("no version"))?; + let channel = version_parts.next().unwrap_or_default().to_string(); + + let commit = items.next().ok_or(err!("no commit info"))?; + // remove ( + if commit.len() == 0 { + return Err(err!("commit format error")); + } + let commit = commit[1..].to_string(); + let date = items.next().ok_or(err!("no date info"))?; + // remove ) + if date.len() == 0 { + return Err(err!("date format error")); + } + let date = date[0..date.len() - 2].to_string(); + + let version_numbers = version + .split(".") + .map(|it| it.parse::()) + .collect::, _>>() + .map_err(|_| err!("version number error"))?; + + if version_numbers.len() != 3 { + return Err(err!("version number format error")); + } + let version = (version_numbers[0], version_numbers[1], version_numbers[2]); + + Ok(RustCInfo { version, channel, commit, date }) +} + +// This is used inside read_version() to locate the ".rustc" section +// from a proc macro crate's binary file. +fn read_section<'a>(dylib_binary: &'a [u8], section_name: &str) -> io::Result<&'a [u8]> { + BinaryFile::parse(dylib_binary) + .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))? + .section_by_name(section_name) + .ok_or_else(|| io::Error::new(io::ErrorKind::InvalidData, "section read error"))? + .data() + .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e)) +} + +// Check the version of rustc that was used to compile a proc macro crate's +// binary file. +// A proc macro crate binary's ".rustc" section has following byte layout: +// * [b'r',b'u',b's',b't',0,0,0,5] is the first 8 bytes +// * ff060000 734e6150 is followed, it's the snappy format magic bytes, +// means bytes from here(including this sequence) are compressed in +// snappy compression format. Version info is inside here, so decompress +// this. +// The bytes you get after decompressing the snappy format portion has +// following layout: +// * [b'r',b'u',b's',b't',0,0,0,5] is the first 8 bytes(again) +// * [crate root bytes] next 4 bytes is to store crate root position, +// according to rustc's source code comment +// * [length byte] next 1 byte tells us how many bytes we should read next +// for the version string's utf8 bytes +// * [version string bytes encoded in utf8] <- GET THIS BOI +// * [some more bytes that we don really care but still there] :-) +// Check this issue for more about the bytes layout: +// https://github.com/rust-analyzer/rust-analyzer/issues/6174 +fn read_version(dylib_path: &Path) -> io::Result { + let dylib_file = File::open(dylib_path)?; + let dylib_mmaped = unsafe { Mmap::map(&dylib_file) }?; + + let dot_rustc = read_section(&dylib_mmaped, ".rustc")?; + + let header = &dot_rustc[..8]; + const EXPECTED_HEADER: [u8; 8] = [b'r', b'u', b's', b't', 0, 0, 0, 5]; + // check if header is valid + if header != EXPECTED_HEADER { + return Err(io::Error::new( + io::ErrorKind::InvalidData, + format!("only metadata version 5 is supported, section header was: {:?}", header), + )); + } + + let snappy_portion = &dot_rustc[8..]; + + let mut snappy_decoder = SnapDecoder::new(snappy_portion); + + // the bytes before version string bytes, so this basically is: + // 8 bytes for [b'r',b'u',b's',b't',0,0,0,5] + // 4 bytes for [crate root bytes] + // 1 byte for length of version string + // so 13 bytes in total, and we should check the 13th byte + // to know the length + let mut bytes_before_version = [0u8; 13]; + snappy_decoder.read_exact(&mut bytes_before_version)?; + let length = bytes_before_version[12]; // what? can't use -1 indexing? + + let mut version_string_utf8 = vec![0u8; length as usize]; + snappy_decoder.read_exact(&mut version_string_utf8)?; + let version_string = String::from_utf8(version_string_utf8); + version_string.map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e)) +} -- cgit v1.2.3