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use crate::structure::Nixpkgs;
use crate::utils;
use crate::utils::{ErrorWriter, LineIndex};
use anyhow::Context;
use rnix::{Root, SyntaxKind::NODE_PATH};
use std::ffi::OsStr;
use std::fs::read_to_string;
use std::io;
use std::path::{Path, PathBuf};
/// Small helper so we don't need to pass in the same arguments to all functions
struct PackageContext<'a, W: io::Write> {
error_writer: &'a mut ErrorWriter<W>,
/// The package directory relative to Nixpkgs, such as `pkgs/by-name/fo/foo`
relative_package_dir: &'a PathBuf,
/// The absolute package directory
absolute_package_dir: &'a PathBuf,
}
/// Check that every package directory in pkgs/by-name doesn't link to outside that directory.
/// Both symlinks and Nix path expressions are checked.
pub fn check_references<W: io::Write>(
error_writer: &mut ErrorWriter<W>,
nixpkgs: &Nixpkgs,
) -> anyhow::Result<()> {
// Check the directories for each package separately
for package_name in &nixpkgs.package_names {
let relative_package_dir = Nixpkgs::relative_dir_for_package(package_name);
let mut context = PackageContext {
error_writer,
relative_package_dir: &relative_package_dir,
absolute_package_dir: &nixpkgs.path.join(&relative_package_dir),
};
// The empty argument here is the subpath under the package directory to check
// An empty one means the package directory itself
check_path(&mut context, Path::new("")).context(format!(
"While checking the references in package directory {}",
relative_package_dir.display()
))?;
}
Ok(())
}
/// Checks for a specific path to not have references outside
fn check_path<W: io::Write>(context: &mut PackageContext<W>, subpath: &Path) -> anyhow::Result<()> {
let path = context.absolute_package_dir.join(subpath);
if path.is_symlink() {
// Check whether the symlink resolves to outside the package directory
match path.canonicalize() {
Ok(target) => {
// No need to handle the case of it being inside the directory, since we scan through the
// entire directory recursively anyways
if let Err(_prefix_error) = target.strip_prefix(context.absolute_package_dir) {
context.error_writer.write(&format!(
"{}: Path {} is a symlink pointing to a path outside the directory of that package.",
context.relative_package_dir.display(),
subpath.display(),
))?;
}
}
Err(e) => {
context.error_writer.write(&format!(
"{}: Path {} is a symlink which cannot be resolved: {e}.",
context.relative_package_dir.display(),
subpath.display(),
))?;
}
}
} else if path.is_dir() {
// Recursively check each entry
for entry in utils::read_dir_sorted(&path)? {
let entry_subpath = subpath.join(entry.file_name());
check_path(context, &entry_subpath)
.context(format!("Error while recursing into {}", subpath.display()))?
}
} else if path.is_file() {
// Only check Nix files
if let Some(ext) = path.extension() {
if ext == OsStr::new("nix") {
check_nix_file(context, subpath).context(format!(
"Error while checking Nix file {}",
subpath.display()
))?
}
}
} else {
// This should never happen, git doesn't support other file types
anyhow::bail!("Unsupported file type for path {}", subpath.display());
}
Ok(())
}
/// Check whether a nix file contains path expression references pointing outside the package
/// directory
fn check_nix_file<W: io::Write>(
context: &mut PackageContext<W>,
subpath: &Path,
) -> anyhow::Result<()> {
let path = context.absolute_package_dir.join(subpath);
let parent_dir = path.parent().context(format!(
"Could not get parent of path {}",
subpath.display()
))?;
let contents =
read_to_string(&path).context(format!("Could not read file {}", subpath.display()))?;
let root = Root::parse(&contents);
if let Some(error) = root.errors().first() {
context.error_writer.write(&format!(
"{}: File {} could not be parsed by rnix: {}",
context.relative_package_dir.display(),
subpath.display(),
error,
))?;
return Ok(());
}
let line_index = LineIndex::new(&contents);
for node in root.syntax().descendants() {
// We're only interested in Path expressions
if node.kind() != NODE_PATH {
continue;
}
let text = node.text().to_string();
let line = line_index.line(node.text_range().start().into());
// Filters out ./foo/${bar}/baz
// TODO: We can just check ./foo
if node.children().count() != 0 {
context.error_writer.write(&format!(
"{}: File {} at line {line} contains the path expression \"{}\", which is not yet supported and may point outside the directory of that package.",
context.relative_package_dir.display(),
subpath.display(),
text
))?;
continue;
}
// Filters out search paths like <nixpkgs>
if text.starts_with('<') {
context.error_writer.write(&format!(
"{}: File {} at line {line} contains the nix search path expression \"{}\" which may point outside the directory of that package.",
context.relative_package_dir.display(),
subpath.display(),
text
))?;
continue;
}
// Resolves the reference of the Nix path
// turning `../baz` inside `/foo/bar/default.nix` to `/foo/baz`
match parent_dir.join(Path::new(&text)).canonicalize() {
Ok(target) => {
// Then checking if it's still in the package directory
// No need to handle the case of it being inside the directory, since we scan through the
// entire directory recursively anyways
if let Err(_prefix_error) = target.strip_prefix(context.absolute_package_dir) {
context.error_writer.write(&format!(
"{}: File {} at line {line} contains the path expression \"{}\" which may point outside the directory of that package.",
context.relative_package_dir.display(),
subpath.display(),
text,
))?;
}
}
Err(e) => {
context.error_writer.write(&format!(
"{}: File {} at line {line} contains the path expression \"{}\" which cannot be resolved: {e}.",
context.relative_package_dir.display(),
subpath.display(),
text,
))?;
}
};
}
Ok(())
}
|