1 //! Checks the licenses of third-party dependencies.
3 use cargo_metadata::{Metadata, Package, PackageId, Resolve};
4 use std::collections::{BTreeSet, HashSet};
7 /// These are licenses that are allowed for all crates, including the runtime,
9 const LICENSES: &[&str] = &[
16 "Apache-2.0 WITH LLVM-exception OR Apache-2.0 OR MIT", // wasi license
20 "0BSD OR MIT OR Apache-2.0", // adler license
21 "Zlib OR Apache-2.0 OR MIT", // tinyvec
24 /// These are exceptions to Rust's permissive licensing policy, and
25 /// should be considered bugs. Exceptions are only allowed in Rust
26 /// tooling. It is _crucial_ that no exception crates be dependencies
27 /// of the Rust runtime (std/test).
28 const EXCEPTIONS: &[(&str, &str)] = &[
29 ("mdbook", "MPL-2.0"), // mdbook
30 ("openssl", "Apache-2.0"), // cargo, mdbook
31 ("colored", "MPL-2.0"), // rustfmt
32 ("ordslice", "Apache-2.0"), // rls
33 ("ryu", "Apache-2.0 OR BSL-1.0"), // rls/cargo/... (because of serde)
34 ("bytesize", "Apache-2.0"), // cargo
35 ("im-rc", "MPL-2.0+"), // cargo
36 ("sized-chunks", "MPL-2.0+"), // cargo via im-rc
37 ("bitmaps", "MPL-2.0+"), // cargo via im-rc
38 ("crossbeam-queue", "MIT/Apache-2.0 AND BSD-2-Clause"), // rls via rayon
39 ("instant", "BSD-3-Clause"), // rustc_driver/tracing-subscriber/parking_lot
40 ("snap", "BSD-3-Clause"), // rustc
41 // FIXME: this dependency violates the documentation comment above:
42 ("fortanix-sgx-abi", "MPL-2.0"), // libstd but only for `sgx` target
45 const EXCEPTIONS_CRANELIFT: &[(&str, &str)] = &[
46 ("cranelift-bforest", "Apache-2.0 WITH LLVM-exception"),
47 ("cranelift-codegen", "Apache-2.0 WITH LLVM-exception"),
48 ("cranelift-codegen-meta", "Apache-2.0 WITH LLVM-exception"),
49 ("cranelift-codegen-shared", "Apache-2.0 WITH LLVM-exception"),
50 ("cranelift-entity", "Apache-2.0 WITH LLVM-exception"),
51 ("cranelift-frontend", "Apache-2.0 WITH LLVM-exception"),
52 ("cranelift-jit", "Apache-2.0 WITH LLVM-exception"),
53 ("cranelift-module", "Apache-2.0 WITH LLVM-exception"),
54 ("cranelift-native", "Apache-2.0 WITH LLVM-exception"),
55 ("cranelift-object", "Apache-2.0 WITH LLVM-exception"),
56 ("libloading", "ISC"),
57 ("mach", "BSD-2-Clause"),
58 ("regalloc", "Apache-2.0 WITH LLVM-exception"),
59 ("target-lexicon", "Apache-2.0 WITH LLVM-exception"),
62 /// These are the root crates that are part of the runtime. The licenses for
63 /// these and all their dependencies *must not* be in the exception list.
64 const RUNTIME_CRATES: &[&str] = &["std", "core", "alloc", "test", "panic_abort", "panic_unwind"];
66 /// Crates whose dependencies must be explicitly permitted.
67 const RESTRICTED_DEPENDENCY_CRATES: &[&str] = &["rustc_driver", "rustc_codegen_llvm"];
69 /// Crates rustc is allowed to depend on. Avoid adding to the list if possible.
71 /// This list is here to provide a speed-bump to adding a new dependency to
72 /// rustc. Please check with the compiler team before adding an entry.
73 const PERMITTED_DEPENDENCIES: &[&str] = &[
153 "perf-event-open-sys",
196 "stable_deref_trait",
207 "tracing-attributes",
211 "tracing-subscriber",
214 "unicode-normalization",
223 "winapi-i686-pc-windows-gnu",
225 "winapi-x86_64-pc-windows-gnu",
226 // this is a false-positive: it's only used by rustfmt, but because it's enabled through a feature, tidy thinks it's used by rustc as well.
230 const PERMITTED_CRANELIFT_DEPENDENCIES: &[&str] = &[
238 "cranelift-codegen-meta",
239 "cranelift-codegen-shared",
241 "cranelift-frontend",
262 "winapi-i686-pc-windows-gnu",
263 "winapi-x86_64-pc-windows-gnu",
266 const FORBIDDEN_TO_HAVE_DUPLICATES: &[&str] = &[
267 // These two crates take quite a long time to build, so don't allow two versions of them
268 // to accidentally sneak into our dependency graph, in order to ensure we keep our CI times
271 "rustc-ap-rustc_ast",
274 /// Dependency checks.
276 /// `root` is path to the directory with the root `Cargo.toml` (for the workspace). `cargo` is path
277 /// to the cargo executable.
278 pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
279 let mut cmd = cargo_metadata::MetadataCommand::new();
280 cmd.cargo_path(cargo)
281 .manifest_path(root.join("Cargo.toml"))
282 .features(cargo_metadata::CargoOpt::AllFeatures);
283 let metadata = t!(cmd.exec());
284 let runtime_ids = compute_runtime_crates(&metadata);
285 check_exceptions(&metadata, EXCEPTIONS, runtime_ids, bad);
286 check_dependencies(&metadata, PERMITTED_DEPENDENCIES, RESTRICTED_DEPENDENCY_CRATES, bad);
287 check_crate_duplicate(&metadata, FORBIDDEN_TO_HAVE_DUPLICATES, bad);
288 check_rustfix(&metadata, bad);
290 // Check rustc_codegen_cranelift independently as it has it's own workspace.
291 let mut cmd = cargo_metadata::MetadataCommand::new();
292 cmd.cargo_path(cargo)
293 .manifest_path(root.join("compiler/rustc_codegen_cranelift/Cargo.toml"))
294 .features(cargo_metadata::CargoOpt::AllFeatures);
295 let metadata = t!(cmd.exec());
296 let runtime_ids = HashSet::new();
297 check_exceptions(&metadata, EXCEPTIONS_CRANELIFT, runtime_ids, bad);
300 PERMITTED_CRANELIFT_DEPENDENCIES,
301 &["rustc_codegen_cranelift"],
304 check_crate_duplicate(&metadata, &[], bad);
307 /// Check that all licenses are in the valid list in `LICENSES`.
309 /// Packages listed in `EXCEPTIONS` are allowed for tools.
312 exceptions: &[(&str, &str)],
313 runtime_ids: HashSet<&PackageId>,
316 // Validate the EXCEPTIONS list hasn't changed.
317 for (name, license) in exceptions {
318 // Check that the package actually exists.
319 if !metadata.packages.iter().any(|p| p.name == *name) {
322 "could not find exception package `{}`\n\
323 Remove from EXCEPTIONS list if it is no longer used.",
327 // Check that the license hasn't changed.
328 for pkg in metadata.packages.iter().filter(|p| p.name == *name) {
333 "dependency exception `{}` does not declare a license expression",
337 Some(pkg_license) => {
338 if pkg_license.as_str() != *license {
339 println!("dependency exception `{}` license has changed", name);
340 println!(" previously `{}` now `{}`", license, pkg_license);
341 println!(" update EXCEPTIONS for the new license");
349 let exception_names: Vec<_> = exceptions.iter().map(|(name, _license)| *name).collect();
351 // Check if any package does not have a valid license.
352 for pkg in &metadata.packages {
353 if pkg.source.is_none() {
354 // No need to check local packages.
357 if !runtime_ids.contains(&pkg.id) && exception_names.contains(&pkg.name.as_str()) {
360 let license = match &pkg.license {
361 Some(license) => license,
363 tidy_error!(bad, "dependency `{}` does not define a license expression", pkg.id);
367 if !LICENSES.contains(&license.as_str()) {
368 if pkg.name == "fortanix-sgx-abi" {
369 // This is a specific exception because SGX is considered
370 // "third party". See
371 // https://github.com/rust-lang/rust/issues/62620 for more. In
372 // general, these should never be added.
375 tidy_error!(bad, "invalid license `{}` in `{}`", license, pkg.id);
380 /// Checks the dependency of `RESTRICTED_DEPENDENCY_CRATES` at the given path. Changes `bad` to
381 /// `true` if a check failed.
383 /// Specifically, this checks that the dependencies are on the `PERMITTED_DEPENDENCIES`.
384 fn check_dependencies(
386 permitted_dependencies: &[&'static str],
387 restricted_dependency_crates: &[&'static str],
390 // Check that the PERMITTED_DEPENDENCIES does not have unused entries.
391 for name in permitted_dependencies {
392 if !metadata.packages.iter().any(|p| p.name == *name) {
395 "could not find allowed package `{}`\n\
396 Remove from PERMITTED_DEPENDENCIES list if it is no longer used.",
401 // Get the list in a convenient form.
402 let permitted_dependencies: HashSet<_> = permitted_dependencies.iter().cloned().collect();
404 // Check dependencies.
405 let mut visited = BTreeSet::new();
406 let mut unapproved = BTreeSet::new();
407 for &krate in restricted_dependency_crates.iter() {
408 let pkg = pkg_from_name(metadata, krate);
410 check_crate_dependencies(&permitted_dependencies, metadata, &mut visited, pkg);
411 unapproved.append(&mut bad);
414 if !unapproved.is_empty() {
415 tidy_error!(bad, "Dependencies not explicitly permitted:");
416 for dep in unapproved {
417 println!("* {}", dep);
422 /// Checks the dependencies of the given crate from the given cargo metadata to see if they are on
423 /// the list of permitted dependencies. Returns a list of disallowed dependencies.
424 fn check_crate_dependencies<'a>(
425 permitted_dependencies: &'a HashSet<&'static str>,
426 metadata: &'a Metadata,
427 visited: &mut BTreeSet<&'a PackageId>,
429 ) -> BTreeSet<&'a PackageId> {
430 // This will contain bad deps.
431 let mut unapproved = BTreeSet::new();
433 // Check if we have already visited this crate.
434 if visited.contains(&krate.id) {
438 visited.insert(&krate.id);
440 // If this path is in-tree, we don't require it to be explicitly permitted.
441 if krate.source.is_some() {
442 // If this dependency is not on `PERMITTED_DEPENDENCIES`, add to bad set.
443 if !permitted_dependencies.contains(krate.name.as_str()) {
444 unapproved.insert(&krate.id);
448 // Do a DFS in the crate graph.
449 let to_check = deps_of(metadata, &krate.id);
451 for dep in to_check {
452 let mut bad = check_crate_dependencies(permitted_dependencies, metadata, visited, dep);
453 unapproved.append(&mut bad);
459 /// Prevents multiple versions of some expensive crates.
460 fn check_crate_duplicate(
462 forbidden_to_have_duplicates: &[&str],
465 for &name in forbidden_to_have_duplicates {
466 let matches: Vec<_> = metadata.packages.iter().filter(|pkg| pkg.name == name).collect();
467 match matches.len() {
471 "crate `{}` is missing, update `check_crate_duplicate` \
472 if it is no longer used",
480 "crate `{}` is duplicated in `Cargo.lock`, \
481 it is too expensive to build multiple times, \
482 so make sure only one version appears across all dependencies",
486 println!(" * {}", pkg.id);
493 /// Returns a list of dependencies for the given package.
494 fn deps_of<'a>(metadata: &'a Metadata, pkg_id: &'a PackageId) -> Vec<&'a Package> {
495 let resolve = metadata.resolve.as_ref().unwrap();
499 .find(|n| &n.id == pkg_id)
500 .unwrap_or_else(|| panic!("could not find `{}` in resolve", pkg_id));
504 metadata.packages.iter().find(|pkg| pkg.id == dep.pkg).unwrap_or_else(|| {
505 panic!("could not find dep `{}` for pkg `{}` in resolve", dep.pkg, pkg_id)
511 /// Finds a package with the given name.
512 fn pkg_from_name<'a>(metadata: &'a Metadata, name: &'static str) -> &'a Package {
513 let mut i = metadata.packages.iter().filter(|p| p.name == name);
515 i.next().unwrap_or_else(|| panic!("could not find package `{}` in package list", name));
516 assert!(i.next().is_none(), "more than one package found for `{}`", name);
520 /// Finds all the packages that are in the rust runtime.
521 fn compute_runtime_crates<'a>(metadata: &'a Metadata) -> HashSet<&'a PackageId> {
522 let resolve = metadata.resolve.as_ref().unwrap();
523 let mut result = HashSet::new();
524 for name in RUNTIME_CRATES {
525 let id = &pkg_from_name(metadata, name).id;
526 normal_deps_of_r(resolve, id, &mut result);
531 /// Recursively find all normal dependencies.
532 fn normal_deps_of_r<'a>(
533 resolve: &'a Resolve,
534 pkg_id: &'a PackageId,
535 result: &mut HashSet<&'a PackageId>,
537 if !result.insert(pkg_id) {
543 .find(|n| &n.id == pkg_id)
544 .unwrap_or_else(|| panic!("could not find `{}` in resolve", pkg_id));
545 for dep in &node.deps {
546 normal_deps_of_r(resolve, &dep.pkg, result);
550 fn check_rustfix(metadata: &Metadata, bad: &mut bool) {
551 let cargo = pkg_from_name(metadata, "cargo");
552 let compiletest = pkg_from_name(metadata, "compiletest");
553 let cargo_deps = deps_of(metadata, &cargo.id);
554 let compiletest_deps = deps_of(metadata, &compiletest.id);
555 let cargo_rustfix = cargo_deps.iter().find(|p| p.name == "rustfix").unwrap();
556 let compiletest_rustfix = compiletest_deps.iter().find(|p| p.name == "rustfix").unwrap();
557 if cargo_rustfix.version != compiletest_rustfix.version {
560 "cargo's rustfix version {} does not match compiletest's rustfix version {}\n\
561 rustfix should be kept in sync, update the cargo side first, and then update \
562 compiletest along with cargo.",
563 cargo_rustfix.version,
564 compiletest_rustfix.version