#include "fetchers.hh" #include "cache.hh" #include "globals.hh" #include "tarfile.hh" #include "store-api.hh" #include "url-parts.hh" #include "pathlocks.hh" #include "util.hh" #include "git.hh" #include "fetch-settings.hh" #include #include #include #include using namespace std::string_literals; namespace nix::fetchers { namespace { // Explicit initial branch of our bare repo to suppress warnings from new version of git. // The value itself does not matter, since we always fetch a specific revision or branch. // It is set with `-c init.defaultBranch=` instead of `--initial-branch=` to stay compatible with // old version of git, which will ignore unrecognized `-c` options. const std::string gitInitialBranch = "__nix_dummy_branch"; bool isCacheFileWithinTtl(time_t now, const struct stat & st) { return st.st_mtime + settings.tarballTtl > now; } bool touchCacheFile(const Path & path, time_t touch_time) { struct timeval times[2]; times[0].tv_sec = touch_time; times[0].tv_usec = 0; times[1].tv_sec = touch_time; times[1].tv_usec = 0; return lutimes(path.c_str(), times) == 0; } Path getCachePath(std::string_view key) { return getCacheDir() + "/nix/gitv3/" + hashString(htSHA256, key).to_string(Base32, false); } // Returns the name of the HEAD branch. // // Returns the head branch name as reported by git ls-remote --symref, e.g., if // ls-remote returns the output below, "main" is returned based on the ref line. // // ref: refs/heads/main HEAD // ... std::optional readHead(const Path & path) { auto [status, output] = runProgram(RunOptions { .program = "git", // FIXME: use 'HEAD' to avoid returning all refs .args = {"ls-remote", "--symref", path}, }); if (status != 0) return std::nullopt; std::string_view line = output; line = line.substr(0, line.find("\n")); if (const auto parseResult = git::parseLsRemoteLine(line)) { switch (parseResult->kind) { case git::LsRemoteRefLine::Kind::Symbolic: debug("resolved HEAD ref '%s' for repo '%s'", parseResult->target, path); break; case git::LsRemoteRefLine::Kind::Object: debug("resolved HEAD rev '%s' for repo '%s'", parseResult->target, path); break; } return parseResult->target; } return std::nullopt; } // Persist the HEAD ref from the remote repo in the local cached repo. bool storeCachedHead(const std::string & actualUrl, const std::string & headRef) { Path cacheDir = getCachePath(actualUrl); try { runProgram("git", true, { "-C", cacheDir, "--git-dir", ".", "symbolic-ref", "--", "HEAD", headRef }); } catch (ExecError &e) { if (!WIFEXITED(e.status)) throw; return false; } /* No need to touch refs/HEAD, because `git symbolic-ref` updates the mtime. */ return true; } std::optional readHeadCached(const std::string & actualUrl) { // Create a cache path to store the branch of the HEAD ref. Append something // in front of the URL to prevent collision with the repository itself. Path cacheDir = getCachePath(actualUrl); Path headRefFile = cacheDir + "/HEAD"; time_t now = time(0); struct stat st; std::optional cachedRef; if (stat(headRefFile.c_str(), &st) == 0) { cachedRef = readHead(cacheDir); if (cachedRef != std::nullopt && *cachedRef != gitInitialBranch && isCacheFileWithinTtl(now, st)) { debug("using cached HEAD ref '%s' for repo '%s'", *cachedRef, actualUrl); return cachedRef; } } auto ref = readHead(actualUrl); if (ref) return ref; if (cachedRef) { // If the cached git ref is expired in fetch() below, and the 'git fetch' // fails, it falls back to continuing with the most recent version. // This function must behave the same way, so we return the expired // cached ref here. warn("could not get HEAD ref for repository '%s'; using expired cached ref '%s'", actualUrl, *cachedRef); return *cachedRef; } return std::nullopt; } bool isNotDotGitDirectory(const Path & path) { return baseNameOf(path) != ".git"; } struct WorkdirInfo { bool clean = false; bool hasHead = false; }; // Returns whether a git workdir is clean and has commits. WorkdirInfo getWorkdirInfo(const Input & input, const Path & workdir) { const bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false); std::string gitDir(".git"); auto env = getEnv(); // Set LC_ALL to C: because we rely on the error messages from git rev-parse to determine what went wrong // that way unknown errors can lead to a failure instead of continuing through the wrong code path env["LC_ALL"] = "C"; /* Check whether HEAD points to something that looks like a commit, since that is the refrence we want to use later on. */ auto result = runProgram(RunOptions { .program = "git", .args = { "-C", workdir, "--git-dir", gitDir, "rev-parse", "--verify", "--no-revs", "HEAD^{commit}" }, .environment = env, .mergeStderrToStdout = true }); auto exitCode = WEXITSTATUS(result.first); auto errorMessage = result.second; if (errorMessage.find("fatal: not a git repository") != std::string::npos) { throw Error("'%s' is not a Git repository", workdir); } else if (errorMessage.find("fatal: Needed a single revision") != std::string::npos) { // indicates that the repo does not have any commits // we want to proceed and will consider it dirty later } else if (exitCode != 0) { // any other errors should lead to a failure throw Error("getting the HEAD of the Git tree '%s' failed with exit code %d:\n%s", workdir, exitCode, errorMessage); } bool clean = false; bool hasHead = exitCode == 0; try { if (hasHead) { // Using git diff is preferrable over lower-level operations here, // because its conceptually simpler and we only need the exit code anyways. auto gitDiffOpts = Strings({ "-C", workdir, "--git-dir", gitDir, "diff", "HEAD", "--quiet"}); if (!submodules) { // Changes in submodules should only make the tree dirty // when those submodules will be copied as well. gitDiffOpts.emplace_back("--ignore-submodules"); } gitDiffOpts.emplace_back("--"); runProgram("git", true, gitDiffOpts); clean = true; } } catch (ExecError & e) { if (!WIFEXITED(e.status) || WEXITSTATUS(e.status) != 1) throw; } return WorkdirInfo { .clean = clean, .hasHead = hasHead }; } std::pair fetchFromWorkdir(ref store, Input & input, const Path & workdir, const WorkdirInfo & workdirInfo) { const bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false); auto gitDir = ".git"; if (!fetchSettings.allowDirty) throw Error("Git tree '%s' is dirty", workdir); if (fetchSettings.warnDirty) warn("Git tree '%s' is dirty", workdir); auto gitOpts = Strings({ "-C", workdir, "--git-dir", gitDir, "ls-files", "-z" }); if (submodules) gitOpts.emplace_back("--recurse-submodules"); auto files = tokenizeString>( runProgram("git", true, gitOpts), "\0"s); Path actualPath(absPath(workdir)); PathFilter filter = [&](const Path & p) -> bool { assert(hasPrefix(p, actualPath)); std::string file(p, actualPath.size() + 1); auto st = lstat(p); if (S_ISDIR(st.st_mode)) { auto prefix = file + "/"; auto i = files.lower_bound(prefix); return i != files.end() && hasPrefix(*i, prefix); } return files.count(file); }; auto storePath = store->addToStore(input.getName(), actualPath, FileIngestionMethod::Recursive, htSHA256, filter); // FIXME: maybe we should use the timestamp of the last // modified dirty file? input.attrs.insert_or_assign( "lastModified", workdirInfo.hasHead ? std::stoull(runProgram("git", true, { "-C", actualPath, "--git-dir", gitDir, "log", "-1", "--format=%ct", "--no-show-signature", "HEAD" })) : 0); return {std::move(storePath), input}; } } // end namespace struct GitInputScheme : InputScheme { std::optional inputFromURL(const ParsedURL & url) const override { if (url.scheme != "git" && url.scheme != "git+http" && url.scheme != "git+https" && url.scheme != "git+ssh" && url.scheme != "git+file") return {}; auto url2(url); if (hasPrefix(url2.scheme, "git+")) url2.scheme = std::string(url2.scheme, 4); url2.query.clear(); Attrs attrs; attrs.emplace("type", "git"); for (auto & [name, value] : url.query) { if (name == "rev" || name == "ref") attrs.emplace(name, value); else if (name == "shallow" || name == "submodules") attrs.emplace(name, Explicit { value == "1" }); else url2.query.emplace(name, value); } attrs.emplace("url", url2.to_string()); return inputFromAttrs(attrs); } std::optional inputFromAttrs(const Attrs & attrs) const override { if (maybeGetStrAttr(attrs, "type") != "git") return {}; for (auto & [name, value] : attrs) if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "shallow" && name != "submodules" && name != "lastModified" && name != "revCount" && name != "narHash" && name != "allRefs" && name != "name") throw Error("unsupported Git input attribute '%s'", name); parseURL(getStrAttr(attrs, "url")); maybeGetBoolAttr(attrs, "shallow"); maybeGetBoolAttr(attrs, "submodules"); maybeGetBoolAttr(attrs, "allRefs"); if (auto ref = maybeGetStrAttr(attrs, "ref")) { if (std::regex_search(*ref, badGitRefRegex)) throw BadURL("invalid Git branch/tag name '%s'", *ref); } Input input; input.attrs = attrs; return input; } ParsedURL toURL(const Input & input) const override { auto url = parseURL(getStrAttr(input.attrs, "url")); if (url.scheme != "git") url.scheme = "git+" + url.scheme; if (auto rev = input.getRev()) url.query.insert_or_assign("rev", rev->gitRev()); if (auto ref = input.getRef()) url.query.insert_or_assign("ref", *ref); if (maybeGetBoolAttr(input.attrs, "shallow").value_or(false)) url.query.insert_or_assign("shallow", "1"); return url; } bool hasAllInfo(const Input & input) const override { bool maybeDirty = !input.getRef(); bool shallow = maybeGetBoolAttr(input.attrs, "shallow").value_or(false); return maybeGetIntAttr(input.attrs, "lastModified") && (shallow || maybeDirty || maybeGetIntAttr(input.attrs, "revCount")); } Input applyOverrides( const Input & input, std::optional ref, std::optional rev) const override { auto res(input); if (rev) res.attrs.insert_or_assign("rev", rev->gitRev()); if (ref) res.attrs.insert_or_assign("ref", *ref); if (!res.getRef() && res.getRev()) throw Error("Git input '%s' has a commit hash but no branch/tag name", res.to_string()); return res; } void clone(const Input & input, const Path & destDir) const override { auto [isLocal, actualUrl] = getActualUrl(input); Strings args = {"clone"}; args.push_back(actualUrl); if (auto ref = input.getRef()) { args.push_back("--branch"); args.push_back(*ref); } if (input.getRev()) throw UnimplementedError("cloning a specific revision is not implemented"); args.push_back(destDir); runProgram("git", true, args); } std::optional getSourcePath(const Input & input) override { auto url = parseURL(getStrAttr(input.attrs, "url")); if (url.scheme == "file" && !input.getRef() && !input.getRev()) return url.path; return {}; } void markChangedFile(const Input & input, std::string_view file, std::optional commitMsg) override { auto sourcePath = getSourcePath(input); assert(sourcePath); auto gitDir = ".git"; runProgram("git", true, { "-C", *sourcePath, "--git-dir", gitDir, "add", "--intent-to-add", "--", std::string(file) }); if (commitMsg) runProgram("git", true, { "-C", *sourcePath, "--git-dir", gitDir, "commit", std::string(file), "-m", *commitMsg }); } std::pair getActualUrl(const Input & input) const { // file:// URIs are normally not cloned (but otherwise treated the // same as remote URIs, i.e. we don't use the working tree or // HEAD). Exception: If _NIX_FORCE_HTTP is set, or the repo is a bare git // repo, treat as a remote URI to force a clone. static bool forceHttp = getEnv("_NIX_FORCE_HTTP") == "1"; // for testing auto url = parseURL(getStrAttr(input.attrs, "url")); bool isBareRepository = url.scheme == "file" && !pathExists(url.path + "/.git"); bool isLocal = url.scheme == "file" && !forceHttp && !isBareRepository; return {isLocal, isLocal ? url.path : url.base}; } std::pair fetch(ref store, const Input & _input) override { Input input(_input); auto gitDir = ".git"; std::string name = input.getName(); bool shallow = maybeGetBoolAttr(input.attrs, "shallow").value_or(false); bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false); bool allRefs = maybeGetBoolAttr(input.attrs, "allRefs").value_or(false); std::string cacheType = "git"; if (shallow) cacheType += "-shallow"; if (submodules) cacheType += "-submodules"; if (allRefs) cacheType += "-all-refs"; auto checkHashType = [&](const std::optional & hash) { if (hash.has_value() && !(hash->type == htSHA1 || hash->type == htSHA256)) throw Error("Hash '%s' is not supported by Git. Supported types are sha1 and sha256.", hash->to_string(Base16, true)); }; auto getLockedAttrs = [&]() { checkHashType(input.getRev()); return Attrs({ {"type", cacheType}, {"name", name}, {"rev", input.getRev()->gitRev()}, }); }; auto makeResult = [&](const Attrs & infoAttrs, StorePath && storePath) -> std::pair { assert(input.getRev()); assert(!_input.getRev() || _input.getRev() == input.getRev()); if (!shallow) input.attrs.insert_or_assign("revCount", getIntAttr(infoAttrs, "revCount")); input.attrs.insert_or_assign("lastModified", getIntAttr(infoAttrs, "lastModified")); return {std::move(storePath), input}; }; if (input.getRev()) { if (auto res = getCache()->lookup(store, getLockedAttrs())) return makeResult(res->first, std::move(res->second)); } auto [isLocal, actualUrl_] = getActualUrl(input); auto actualUrl = actualUrl_; // work around clang bug /* If this is a local directory and no ref or revision is given, allow fetching directly from a dirty workdir. */ if (!input.getRef() && !input.getRev() && isLocal) { auto workdirInfo = getWorkdirInfo(input, actualUrl); if (!workdirInfo.clean) { return fetchFromWorkdir(store, input, actualUrl, workdirInfo); } } Attrs unlockedAttrs({ {"type", cacheType}, {"name", name}, {"url", actualUrl}, }); Path repoDir; if (isLocal) { if (!input.getRef()) { auto head = readHead(actualUrl); if (!head) { warn("could not read HEAD ref from repo at '%s', using 'master'", actualUrl); head = "master"; } input.attrs.insert_or_assign("ref", *head); unlockedAttrs.insert_or_assign("ref", *head); } if (!input.getRev()) input.attrs.insert_or_assign("rev", Hash::parseAny(chomp(runProgram("git", true, { "-C", actualUrl, "--git-dir", gitDir, "rev-parse", *input.getRef() })), htSHA1).gitRev()); repoDir = actualUrl; } else { const bool useHeadRef = !input.getRef(); if (useHeadRef) { auto head = readHeadCached(actualUrl); if (!head) { warn("could not read HEAD ref from repo at '%s', using 'master'", actualUrl); head = "master"; } input.attrs.insert_or_assign("ref", *head); unlockedAttrs.insert_or_assign("ref", *head); } else { if (!input.getRev()) { unlockedAttrs.insert_or_assign("ref", input.getRef().value()); } } if (auto res = getCache()->lookup(store, unlockedAttrs)) { auto rev2 = Hash::parseAny(getStrAttr(res->first, "rev"), htSHA1); if (!input.getRev() || input.getRev() == rev2) { input.attrs.insert_or_assign("rev", rev2.gitRev()); return makeResult(res->first, std::move(res->second)); } } Path cacheDir = getCachePath(actualUrl); repoDir = cacheDir; gitDir = "."; createDirs(dirOf(cacheDir)); PathLocks cacheDirLock({cacheDir + ".lock"}); if (!pathExists(cacheDir)) { runProgram("git", true, { "-c", "init.defaultBranch=" + gitInitialBranch, "init", "--bare", repoDir }); } Path localRefFile = input.getRef()->compare(0, 5, "refs/") == 0 ? cacheDir + "/" + *input.getRef() : cacheDir + "/refs/heads/" + *input.getRef(); bool doFetch; time_t now = time(0); /* If a rev was specified, we need to fetch if it's not in the repo. */ if (input.getRev()) { try { runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "cat-file", "-e", input.getRev()->gitRev() }); doFetch = false; } catch (ExecError & e) { if (WIFEXITED(e.status)) { doFetch = true; } else { throw; } } } else { if (allRefs) { doFetch = true; } else { /* If the local ref is older than ‘tarball-ttl’ seconds, do a git fetch to update the local ref to the remote ref. */ struct stat st; doFetch = stat(localRefFile.c_str(), &st) != 0 || !isCacheFileWithinTtl(now, st); } } if (doFetch) { Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", actualUrl)); // FIXME: git stderr messes up our progress indicator, so // we're using --quiet for now. Should process its stderr. try { auto ref = input.getRef(); auto fetchRef = allRefs ? "refs/*" : ref->compare(0, 5, "refs/") == 0 ? *ref : ref == "HEAD" ? *ref : "refs/heads/" + *ref; runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "fetch", "--quiet", "--force", "--", actualUrl, fmt("%s:%s", fetchRef, fetchRef) }); } catch (Error & e) { if (!pathExists(localRefFile)) throw; warn("could not update local clone of Git repository '%s'; continuing with the most recent version", actualUrl); } if (!touchCacheFile(localRefFile, now)) warn("could not update mtime for file '%s': %s", localRefFile, strerror(errno)); if (useHeadRef && !storeCachedHead(actualUrl, *input.getRef())) warn("could not update cached head '%s' for '%s'", *input.getRef(), actualUrl); } if (!input.getRev()) input.attrs.insert_or_assign("rev", Hash::parseAny(chomp(readFile(localRefFile)), htSHA1).gitRev()); // cache dir lock is removed at scope end; we will only use read-only operations on specific revisions in the remainder } bool isShallow = chomp(runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "rev-parse", "--is-shallow-repository" })) == "true"; if (isShallow && !shallow) throw Error("'%s' is a shallow Git repository, but shallow repositories are only allowed when `shallow = true;` is specified.", actualUrl); // FIXME: check whether rev is an ancestor of ref. printTalkative("using revision %s of repo '%s'", input.getRev()->gitRev(), actualUrl); /* Now that we know the ref, check again whether we have it in the store. */ if (auto res = getCache()->lookup(store, getLockedAttrs())) return makeResult(res->first, std::move(res->second)); Path tmpDir = createTempDir(); AutoDelete delTmpDir(tmpDir, true); PathFilter filter = defaultPathFilter; auto result = runProgram(RunOptions { .program = "git", .args = { "-C", repoDir, "--git-dir", gitDir, "cat-file", "commit", input.getRev()->gitRev() }, .mergeStderrToStdout = true }); if (WEXITSTATUS(result.first) == 128 && result.second.find("bad file") != std::string::npos) { throw Error( "Cannot find Git revision '%s' in ref '%s' of repository '%s'! " "Please make sure that the " ANSI_BOLD "rev" ANSI_NORMAL " exists on the " ANSI_BOLD "ref" ANSI_NORMAL " you've specified or add " ANSI_BOLD "allRefs = true;" ANSI_NORMAL " to " ANSI_BOLD "fetchGit" ANSI_NORMAL ".", input.getRev()->gitRev(), *input.getRef(), actualUrl ); } if (submodules) { Path tmpGitDir = createTempDir(); AutoDelete delTmpGitDir(tmpGitDir, true); runProgram("git", true, { "-c", "init.defaultBranch=" + gitInitialBranch, "init", tmpDir, "--separate-git-dir", tmpGitDir }); { // TODO: repoDir might lack the ref (it only checks if rev // exists, see FIXME above) so use a big hammer and fetch // everything to ensure we get the rev. Activity act(*logger, lvlTalkative, actUnknown, fmt("making temporary clone of '%s'", tmpDir)); runProgram("git", true, { "-C", tmpDir, "fetch", "--quiet", "--force", "--update-head-ok", "--", repoDir, "refs/*:refs/*" }); } runProgram("git", true, { "-C", tmpDir, "checkout", "--quiet", input.getRev()->gitRev() }); /* Ensure that we use the correct origin for fetching submodules. This matters for submodules with relative URLs. */ if (isLocal) { writeFile(tmpGitDir + "/config", readFile(repoDir + "/" + gitDir + "/config")); /* Restore the config.bare setting we may have just nuked. */ runProgram("git", true, { "-C", tmpDir, "config", "core.bare", "false" }); } else runProgram("git", true, { "-C", tmpDir, "config", "remote.origin.url", actualUrl }); { Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching submodules of '%s'", tmpDir)); runProgram("git", true, { "-C", tmpDir, "submodule", "--quiet", "update", "--init", "--recursive" }); } filter = isNotDotGitDirectory; } else { // FIXME: should pipe this, or find some better way to extract a // revision. auto source = sinkToSource([&](Sink & sink) { runProgram2({ .program = "git", .args = { "-C", repoDir, "--git-dir", gitDir, "archive", input.getRev()->gitRev() }, .standardOut = &sink }); }); unpackTarfile(*source, tmpDir); } auto storePath = store->addToStore(name, tmpDir, FileIngestionMethod::Recursive, htSHA256, filter); auto lastModified = std::stoull(runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "log", "-1", "--format=%ct", "--no-show-signature", input.getRev()->gitRev() })); Attrs infoAttrs({ {"rev", input.getRev()->gitRev()}, {"lastModified", lastModified}, }); if (!shallow) infoAttrs.insert_or_assign("revCount", std::stoull(runProgram("git", true, { "-C", repoDir, "--git-dir", gitDir, "rev-list", "--count", input.getRev()->gitRev() }))); if (!_input.getRev()) getCache()->add( store, unlockedAttrs, infoAttrs, storePath, false); getCache()->add( store, getLockedAttrs(), infoAttrs, storePath, true); return makeResult(infoAttrs, std::move(storePath)); } }; static auto rGitInputScheme = OnStartup([] { registerInputScheme(std::make_unique()); }); }