From 7080321618e29033a8b5dc2f9fc938dcf2df270d Mon Sep 17 00:00:00 2001 From: regnat Date: Tue, 15 Dec 2020 10:54:24 +0100 Subject: [PATCH] Use the fs accessor for readInvalidDerivation Extend `FSAccessor::readFile` to allow not checking that the path is a valid one, and rewrite `readInvalidDerivation` using this extended `readFile`. Several places in the code use `readInvalidDerivation`, either because they need to read a derivation that has been written in the store but not registered yet, or more generally to prevent a deadlock because `readDerivation` tries to lock the state, so can't be called from a place where the lock is already held. However, `readInvalidDerivation` implicitely assumes that the store is a `LocalFSStore`, which isn't always the case. The concrete motivation for this is that it's required for `nix copy --from someBinaryCache` to work, which is tremendously useful for the tests. --- src/libstore/fs-accessor.hh | 9 ++++++++- src/libstore/local-fs-store.cc | 8 ++++---- src/libstore/nar-accessor.cc | 2 +- src/libstore/remote-fs-accessor.cc | 8 ++++---- src/libstore/remote-fs-accessor.hh | 4 ++-- src/libstore/store-api.cc | 21 +++++++++------------ 6 files changed, 28 insertions(+), 24 deletions(-) diff --git a/src/libstore/fs-accessor.hh b/src/libstore/fs-accessor.hh index 64780a6da..c825e84f2 100644 --- a/src/libstore/fs-accessor.hh +++ b/src/libstore/fs-accessor.hh @@ -25,7 +25,14 @@ public: virtual StringSet readDirectory(const Path & path) = 0; - virtual std::string readFile(const Path & path) = 0; + /** + * Read a file inside the store. + * + * If `requireValidPath` is set to `true` (the default), the path must be + * inside a valid store path, otherwise it just needs to be physically + * present (but not necessarily properly registered) + */ + virtual std::string readFile(const Path & path, bool requireValidPath = true) = 0; virtual std::string readLink(const Path & path) = 0; }; diff --git a/src/libstore/local-fs-store.cc b/src/libstore/local-fs-store.cc index e7c3dae92..6de13c73a 100644 --- a/src/libstore/local-fs-store.cc +++ b/src/libstore/local-fs-store.cc @@ -19,10 +19,10 @@ struct LocalStoreAccessor : public FSAccessor LocalStoreAccessor(ref store) : store(store) { } - Path toRealPath(const Path & path) + Path toRealPath(const Path & path, bool requireValidPath = true) { auto storePath = store->toStorePath(path).first; - if (!store->isValidPath(storePath)) + if (requireValidPath && !store->isValidPath(storePath)) throw InvalidPath("path '%1%' is not a valid store path", store->printStorePath(storePath)); return store->getRealStoreDir() + std::string(path, store->storeDir.size()); } @@ -61,9 +61,9 @@ struct LocalStoreAccessor : public FSAccessor return res; } - std::string readFile(const Path & path) override + std::string readFile(const Path & path, bool requireValidPath = true) override { - return nix::readFile(toRealPath(path)); + return nix::readFile(toRealPath(path, requireValidPath)); } std::string readLink(const Path & path) override diff --git a/src/libstore/nar-accessor.cc b/src/libstore/nar-accessor.cc index 1427a0f98..784ebb719 100644 --- a/src/libstore/nar-accessor.cc +++ b/src/libstore/nar-accessor.cc @@ -203,7 +203,7 @@ struct NarAccessor : public FSAccessor return res; } - std::string readFile(const Path & path) override + std::string readFile(const Path & path, bool requireValidPath = true) override { auto i = get(path); if (i.type != FSAccessor::Type::tRegular) diff --git a/src/libstore/remote-fs-accessor.cc b/src/libstore/remote-fs-accessor.cc index 63bde92de..f43456f0b 100644 --- a/src/libstore/remote-fs-accessor.cc +++ b/src/libstore/remote-fs-accessor.cc @@ -43,13 +43,13 @@ void RemoteFSAccessor::addToCache(std::string_view hashPart, const std::string & } } -std::pair, Path> RemoteFSAccessor::fetch(const Path & path_) +std::pair, Path> RemoteFSAccessor::fetch(const Path & path_, bool requireValidPath) { auto path = canonPath(path_); auto [storePath, restPath] = store->toStorePath(path); - if (!store->isValidPath(storePath)) + if (requireValidPath && !store->isValidPath(storePath)) throw InvalidPath("path '%1%' is not a valid store path", store->printStorePath(storePath)); auto i = nars.find(std::string(storePath.hashPart())); @@ -113,9 +113,9 @@ StringSet RemoteFSAccessor::readDirectory(const Path & path) return res.first->readDirectory(res.second); } -std::string RemoteFSAccessor::readFile(const Path & path) +std::string RemoteFSAccessor::readFile(const Path & path, bool requireValidPath) { - auto res = fetch(path); + auto res = fetch(path, requireValidPath); return res.first->readFile(res.second); } diff --git a/src/libstore/remote-fs-accessor.hh b/src/libstore/remote-fs-accessor.hh index 347cf5764..594852d0e 100644 --- a/src/libstore/remote-fs-accessor.hh +++ b/src/libstore/remote-fs-accessor.hh @@ -14,7 +14,7 @@ class RemoteFSAccessor : public FSAccessor Path cacheDir; - std::pair, Path> fetch(const Path & path_); + std::pair, Path> fetch(const Path & path_, bool requireValidPath = true); friend class BinaryCacheStore; @@ -32,7 +32,7 @@ public: StringSet readDirectory(const Path & path) override; - std::string readFile(const Path & path) override; + std::string readFile(const Path & path, bool requireValidPath = true) override; std::string readLink(const Path & path) override; }; diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc index 7bf9235b2..25e28cffa 100644 --- a/src/libstore/store-api.cc +++ b/src/libstore/store-api.cc @@ -1018,26 +1018,23 @@ Derivation Store::derivationFromPath(const StorePath & drvPath) return readDerivation(drvPath); } - -Derivation Store::readDerivation(const StorePath & drvPath) +Derivation readDerivationCommon(Store& store, const StorePath& drvPath, bool requireValidPath) { - auto accessor = getFSAccessor(); + auto accessor = store.getFSAccessor(); try { - return parseDerivation(*this, - accessor->readFile(printStorePath(drvPath)), + return parseDerivation(store, + accessor->readFile(store.printStorePath(drvPath), requireValidPath), Derivation::nameFromPath(drvPath)); } catch (FormatError & e) { - throw Error("error parsing derivation '%s': %s", printStorePath(drvPath), e.msg()); + throw Error("error parsing derivation '%s': %s", store.printStorePath(drvPath), e.msg()); } } +Derivation Store::readDerivation(const StorePath & drvPath) +{ return readDerivationCommon(*this, drvPath, true); } + Derivation Store::readInvalidDerivation(const StorePath & drvPath) -{ - return parseDerivation( - *this, - readFile(Store::toRealPath(drvPath)), - Derivation::nameFromPath(drvPath)); -} +{ return readDerivationCommon(*this, drvPath, false); } }