libchromeos: add API to query /etc/os-release
/etc/os-release fields can come from two different places depending on how we
set them, how the package is installed, etc...
This creates a common API to query field in /etc/os-release and
/etc/os-release.d.
BUG=chromium:420784
TEST=Unittests.
Change-Id: Ic91fd873cd4f6c5e3357991e72d055a12b54c9d1
Reviewed-on: https://chromium-review.googlesource.com/221963
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Bertrand Simonnet <bsimonnet@chromium.org>
diff --git a/chromeos/osrelease_reader.cc b/chromeos/osrelease_reader.cc
new file mode 100644
index 0000000..e6129fe
--- /dev/null
+++ b/chromeos/osrelease_reader.cc
@@ -0,0 +1,58 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <chromeos/osrelease_reader.h>
+
+#include <base/files/file_enumerator.h>
+#include <base/files/file_util.h>
+#include <base/logging.h>
+#include <chromeos/strings/string_utils.h>
+
+namespace chromeos {
+
+bool OsReleaseReader::Load() {
+ return Load(base::FilePath("/"));
+}
+
+bool OsReleaseReader::GetString(const std::string& key,
+ std::string* value) const {
+ CHECK(initialized_) << "OsReleaseReader.Load() must be called first.";
+ return store_.GetString(key, value);
+}
+
+bool OsReleaseReader::LoadTestingOnly(const base::FilePath& root_dir) {
+ return Load(root_dir);
+}
+
+bool OsReleaseReader::Load(const base::FilePath& root_dir) {
+ base::FilePath osrelease = root_dir.Append("etc").Append("os-release");
+ if (!store_.Load(osrelease)) {
+ // /etc/os-release might not be present (cros deploying a new configuration
+ // or no fields set at all). Just print a debug message and continue.
+ DLOG(INFO) << "Could not load fields from " << osrelease.value();
+ }
+
+ base::FilePath osreleased = root_dir.Append("etc").Append("os-release.d");
+ base::FileEnumerator enumerator(osreleased,
+ false,
+ base::FileEnumerator::FILES);
+
+ for (base::FilePath path = enumerator.Next(); !path.empty();
+ path = enumerator.Next()) {
+ std::string content;
+ if (!base::ReadFileToString(path, &content)) {
+ // The only way to fail is if a file exist in /etc/os-release.d but we
+ // cannot read it.
+ PLOG(FATAL) << "Could not read " << path.value();
+ }
+ // There might be a trailing new line. Strip it to keep only the first line
+ // of the file.
+ content = chromeos::string_utils::SplitAtFirst(content, '\n', true).first;
+ store_.SetString(path.BaseName().value(), content);
+ }
+ initialized_ = true;
+ return true;
+}
+
+} // namespace chromeos
diff --git a/chromeos/osrelease_reader.h b/chromeos/osrelease_reader.h
new file mode 100644
index 0000000..8e8c4d0
--- /dev/null
+++ b/chromeos/osrelease_reader.h
@@ -0,0 +1,55 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Wrapper around /etc/os-release and /etc/os-release.d.
+// Standard fields can come from both places depending on how we set them. They
+// should always be accessed through this interface.
+
+#ifndef LIBCHROMEOS_CHROMEOS_OSRELEASE_READER_H_
+#define LIBCHROMEOS_CHROMEOS_OSRELEASE_READER_H_
+
+#include <string>
+
+#include <chromeos/chromeos_export.h>
+#include <chromeos/key_value_store.h>
+#include <gtest/gtest_prod.h>
+
+namespace chromeos {
+
+class CHROMEOS_EXPORT OsReleaseReader {
+ public:
+ // Create an empty reader
+ OsReleaseReader() = default;
+
+ // Loads the key=value pairs from either /etc/os-release.d/<KEY> or
+ // /etc/os-release.
+ // Returns false on errors.
+ bool Load();
+
+ // Same as the private Load method.
+ // This need to be public so that services can use it in testing mode (for
+ // autotest tests for example).
+ // This should not be used in production so suffix it with TestingOnly to
+ // make it obvious.
+ bool LoadTestingOnly(const base::FilePath& root_dir);
+
+ // Getter for the given key. Returns whether the key was found on the store.
+ bool GetString(const std::string& key, std::string* value) const;
+
+ private:
+ // The map storing all the key-value pairs.
+ KeyValueStore store_;
+
+ // os-release can be lazily loaded if need be.
+ bool initialized_;
+
+ // Load the data from a given root_dir. Return false on errors.
+ CHROMEOS_PRIVATE bool Load(const base::FilePath& root_dir);
+
+ DISALLOW_COPY_AND_ASSIGN(OsReleaseReader);
+};
+
+} // namespace chromeos
+
+#endif // LIBCHROMEOS_CHROMEOS_OSRELEASE_READER_H_
diff --git a/chromeos/osrelease_reader_unittest.cc b/chromeos/osrelease_reader_unittest.cc
new file mode 100644
index 0000000..92bfde6
--- /dev/null
+++ b/chromeos/osrelease_reader_unittest.cc
@@ -0,0 +1,96 @@
+// Copyright 2014 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <chromeos/osrelease_reader.h>
+
+#include <base/files/file_util.h>
+#include <base/files/scoped_temp_dir.h>
+#include <gtest/gtest.h>
+
+using std::string;
+
+namespace chromeos {
+
+class OsReleaseReaderTest : public ::testing::Test {
+ public:
+ void SetUp() override {
+ CHECK(temp_dir_.CreateUniqueTempDir());
+ osreleased_ = temp_dir_.path().Append("etc").Append("os-release.d");
+ osrelease_ = temp_dir_.path().Append("etc").Append("os-release");
+ base::CreateDirectory(osreleased_);
+ }
+
+ protected:
+ base::FilePath temp_file_, osrelease_, osreleased_;
+ base::ScopedTempDir temp_dir_;
+ OsReleaseReader store_; // reader under test.
+};
+
+TEST_F(OsReleaseReaderTest, MissingOsReleaseTest) {
+ ASSERT_TRUE(store_.LoadTestingOnly(temp_dir_.path()));
+}
+
+TEST_F(OsReleaseReaderTest, MissingOsReleaseDTest) {
+ base::DeleteFile(osreleased_, true);
+ ASSERT_TRUE(store_.LoadTestingOnly(temp_dir_.path()));
+}
+
+TEST_F(OsReleaseReaderTest, CompleteTest) {
+ string hello = "hello";
+ string ola = "ola";
+ string bob = "bob";
+ string osreleasecontent = "TEST_KEY=bonjour\nNAME=bob\n";
+
+ base::WriteFile(osreleased_.Append("TEST_KEY"), hello.data(), hello.size());
+ base::WriteFile(osreleased_.Append("GREETINGS"), ola.data(), ola.size());
+ base::WriteFile(osrelease_, osreleasecontent.data(), osreleasecontent.size());
+
+ ASSERT_TRUE(store_.LoadTestingOnly(temp_dir_.path()));
+
+ string test_key_value;
+ ASSERT_TRUE(store_.GetString("TEST_KEY", &test_key_value));
+
+ string greetings_value;
+ ASSERT_TRUE(store_.GetString("GREETINGS", &greetings_value));
+
+ string name_value;
+ ASSERT_TRUE(store_.GetString("NAME", &name_value));
+
+ string nonexistent_value;
+ // Getting the string should fail if the key does not exist.
+ ASSERT_FALSE(store_.GetString("DOES_NOT_EXIST", &nonexistent_value));
+
+ // hello in chosen (from os-release.d) instead of bonjour from os-release.
+ ASSERT_EQ(hello, test_key_value);
+
+ // greetings is set to ola.
+ ASSERT_EQ(ola, greetings_value);
+
+ // Name from os-release is set.
+ ASSERT_EQ(bob, name_value);
+}
+
+TEST_F(OsReleaseReaderTest, NoNewLine) {
+ // New lines should be stripped from os-release.d files.
+ string hello = "hello\n";
+ string bonjour = "bonjour\ngarbage";
+
+ base::WriteFile(osreleased_.Append("HELLO"), hello.data(), hello.size());
+ base::WriteFile(osreleased_.Append("BONJOUR"),
+ bonjour.data(),
+ bonjour.size());
+
+ ASSERT_TRUE(store_.LoadTestingOnly(temp_dir_.path()));
+
+ string hello_value;
+ string bonjour_value;
+
+ ASSERT_TRUE(store_.GetString("HELLO", &hello_value));
+ ASSERT_TRUE(store_.GetString("BONJOUR", &bonjour_value));
+
+ ASSERT_EQ("hello", hello_value);
+ ASSERT_EQ("bonjour", bonjour_value);
+}
+
+} // namespace chromeos