blob: 70c6b43184460e46e406f3c9cdf198d041bdb15b [file] [log] [blame]
// Copyright 2014 The Chromium 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 "services/preferences/tracked/tracked_preferences_migration.h"
#include <utility>
#include "base/bind.h"
#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/metrics/histogram.h"
#include "base/values.h"
#include "services/preferences/tracked/dictionary_hash_store_contents.h"
#include "services/preferences/tracked/hash_store_contents.h"
#include "services/preferences/tracked/interceptable_pref_filter.h"
#include "services/preferences/tracked/pref_hash_store.h"
#include "services/preferences/tracked/pref_hash_store_transaction.h"
namespace {
class TrackedPreferencesMigrator
: public base::RefCounted<TrackedPreferencesMigrator> {
public:
enum PrefFilterID { UNPROTECTED_PREF_FILTER, PROTECTED_PREF_FILTER };
TrackedPreferencesMigrator(
const std::set<std::string>& unprotected_pref_names,
const std::set<std::string>& protected_pref_names,
const base::RepeatingCallback<void(const std::string& key)>&
unprotected_store_cleaner,
const base::RepeatingCallback<void(const std::string& key)>&
protected_store_cleaner,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_unprotected_store_write_callback,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_protected_store_write_callback,
std::unique_ptr<PrefHashStore> unprotected_pref_hash_store,
std::unique_ptr<PrefHashStore> protected_pref_hash_store,
InterceptablePrefFilter* unprotected_pref_filter,
InterceptablePrefFilter* protected_pref_filter);
// Stores the data coming in from the filter identified by |id| into this
// class and then calls MigrateIfReady();
void InterceptFilterOnLoad(
PrefFilterID id,
InterceptablePrefFilter::FinalizeFilterOnLoadCallback
finalize_filter_on_load,
std::unique_ptr<base::DictionaryValue> prefs);
private:
friend class base::RefCounted<TrackedPreferencesMigrator>;
~TrackedPreferencesMigrator();
// Proceeds with migration if both |unprotected_prefs_| and |protected_prefs_|
// have been set.
void MigrateIfReady();
const std::set<std::string> unprotected_pref_names_;
const std::set<std::string> protected_pref_names_;
const base::RepeatingCallback<void(const std::string& key)>
unprotected_store_cleaner_;
const base::RepeatingCallback<void(const std::string& key)>
protected_store_cleaner_;
const base::RepeatingCallback<void(base::OnceClosure)>
register_on_successful_unprotected_store_write_callback_;
const base::RepeatingCallback<void(base::OnceClosure)>
register_on_successful_protected_store_write_callback_;
InterceptablePrefFilter::FinalizeFilterOnLoadCallback
finalize_unprotected_filter_on_load_;
InterceptablePrefFilter::FinalizeFilterOnLoadCallback
finalize_protected_filter_on_load_;
std::unique_ptr<PrefHashStore> unprotected_pref_hash_store_;
std::unique_ptr<PrefHashStore> protected_pref_hash_store_;
std::unique_ptr<base::DictionaryValue> unprotected_prefs_;
std::unique_ptr<base::DictionaryValue> protected_prefs_;
DISALLOW_COPY_AND_ASSIGN(TrackedPreferencesMigrator);
};
// Invokes |store_cleaner| for every |keys_to_clean|.
void CleanupPrefStore(
const base::RepeatingCallback<void(const std::string& key)>& store_cleaner,
const std::set<std::string>& keys_to_clean) {
for (std::set<std::string>::const_iterator it = keys_to_clean.begin();
it != keys_to_clean.end(); ++it) {
store_cleaner.Run(*it);
}
}
// If |wait_for_commit_to_destination_store|: schedules (via
// |register_on_successful_destination_store_write_callback|) a cleanup of the
// |keys_to_clean| from the source pref store (through |source_store_cleaner|)
// once the destination pref store they were migrated to was successfully
// written to disk. Otherwise, executes the cleanup right away.
void ScheduleSourcePrefStoreCleanup(
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_destination_store_write_callback,
const base::RepeatingCallback<void(const std::string& key)>&
source_store_cleaner,
const std::set<std::string>& keys_to_clean,
bool wait_for_commit_to_destination_store) {
DCHECK(!keys_to_clean.empty());
if (wait_for_commit_to_destination_store) {
register_on_successful_destination_store_write_callback.Run(
base::BindOnce(&CleanupPrefStore, source_store_cleaner, keys_to_clean));
} else {
CleanupPrefStore(source_store_cleaner, keys_to_clean);
}
}
// Removes hashes for |migrated_pref_names| from |origin_pref_store| using
// the configuration/implementation in |origin_pref_hash_store|.
void CleanupMigratedHashes(const std::set<std::string>& migrated_pref_names,
PrefHashStore* origin_pref_hash_store,
base::DictionaryValue* origin_pref_store) {
DictionaryHashStoreContents dictionary_contents(origin_pref_store);
std::unique_ptr<PrefHashStoreTransaction> transaction(
origin_pref_hash_store->BeginTransaction(&dictionary_contents));
for (std::set<std::string>::const_iterator it = migrated_pref_names.begin();
it != migrated_pref_names.end(); ++it) {
transaction->ClearHash(*it);
}
}
// Copies the value of each pref in |pref_names| which is set in |old_store|,
// but not in |new_store| into |new_store|. Sets |old_store_needs_cleanup| to
// true if any old duplicates remain in |old_store| and sets |new_store_altered|
// to true if any value was copied to |new_store|.
void MigratePrefsFromOldToNewStore(const std::set<std::string>& pref_names,
base::DictionaryValue* old_store,
base::DictionaryValue* new_store,
PrefHashStore* new_hash_store,
bool* old_store_needs_cleanup,
bool* new_store_altered) {
const base::DictionaryValue* old_hash_store_contents =
DictionaryHashStoreContents(old_store).GetContents();
DictionaryHashStoreContents dictionary_contents(new_store);
std::unique_ptr<PrefHashStoreTransaction> new_hash_store_transaction(
new_hash_store->BeginTransaction(&dictionary_contents));
for (std::set<std::string>::const_iterator it = pref_names.begin();
it != pref_names.end(); ++it) {
const std::string& pref_name = *it;
const base::Value* value_in_old_store = NULL;
// If the destination does not have a hash for this pref we will
// unconditionally attempt to move it.
bool destination_hash_missing =
!new_hash_store_transaction->HasHash(pref_name);
// If we migrate the value we will also attempt to migrate the hash.
bool migrated_value = false;
if (old_store->Get(pref_name, &value_in_old_store)) {
// Whether this value ends up being copied below or was left behind by a
// previous incomplete migration, it should be cleaned up.
*old_store_needs_cleanup = true;
if (!new_store->Get(pref_name, NULL)) {
// Copy the value from |old_store| to |new_store| rather than moving it
// to avoid data loss should |old_store| be flushed to disk without
// |new_store| having equivalently been successfully flushed to disk
// (e.g., on crash or in cases where |new_store| is read-only following
// a read error on startup).
new_store->Set(pref_name, std::make_unique<base::Value>(
value_in_old_store->Clone()));
migrated_value = true;
*new_store_altered = true;
}
}
if (destination_hash_missing || migrated_value) {
const base::Value* old_hash = NULL;
if (old_hash_store_contents)
old_hash_store_contents->Get(pref_name, &old_hash);
if (old_hash) {
new_hash_store_transaction->ImportHash(pref_name, old_hash);
*new_store_altered = true;
} else if (!destination_hash_missing) {
// Do not allow values to be migrated without MACs if the destination
// already has a MAC (http://crbug.com/414554). Remove the migrated
// value in order to provide the same no-op behaviour as if the pref was
// added to the wrong file when there was already a value for
// |pref_name| in |new_store|.
new_store->Remove(pref_name, NULL);
*new_store_altered = true;
}
}
}
}
TrackedPreferencesMigrator::TrackedPreferencesMigrator(
const std::set<std::string>& unprotected_pref_names,
const std::set<std::string>& protected_pref_names,
const base::RepeatingCallback<void(const std::string& key)>&
unprotected_store_cleaner,
const base::RepeatingCallback<void(const std::string& key)>&
protected_store_cleaner,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_unprotected_store_write_callback,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_protected_store_write_callback,
std::unique_ptr<PrefHashStore> unprotected_pref_hash_store,
std::unique_ptr<PrefHashStore> protected_pref_hash_store,
InterceptablePrefFilter* unprotected_pref_filter,
InterceptablePrefFilter* protected_pref_filter)
: unprotected_pref_names_(unprotected_pref_names),
protected_pref_names_(protected_pref_names),
unprotected_store_cleaner_(unprotected_store_cleaner),
protected_store_cleaner_(protected_store_cleaner),
register_on_successful_unprotected_store_write_callback_(
register_on_successful_unprotected_store_write_callback),
register_on_successful_protected_store_write_callback_(
register_on_successful_protected_store_write_callback),
unprotected_pref_hash_store_(std::move(unprotected_pref_hash_store)),
protected_pref_hash_store_(std::move(protected_pref_hash_store)) {}
TrackedPreferencesMigrator::~TrackedPreferencesMigrator() {}
void TrackedPreferencesMigrator::InterceptFilterOnLoad(
PrefFilterID id,
InterceptablePrefFilter::FinalizeFilterOnLoadCallback
finalize_filter_on_load,
std::unique_ptr<base::DictionaryValue> prefs) {
switch (id) {
case UNPROTECTED_PREF_FILTER:
finalize_unprotected_filter_on_load_ = std::move(finalize_filter_on_load);
unprotected_prefs_ = std::move(prefs);
break;
case PROTECTED_PREF_FILTER:
finalize_protected_filter_on_load_ = std::move(finalize_filter_on_load);
protected_prefs_ = std::move(prefs);
break;
}
MigrateIfReady();
}
void TrackedPreferencesMigrator::MigrateIfReady() {
// Wait for both stores to have been read before proceeding.
if (!protected_prefs_ || !unprotected_prefs_)
return;
bool protected_prefs_need_cleanup = false;
bool unprotected_prefs_altered = false;
MigratePrefsFromOldToNewStore(
unprotected_pref_names_, protected_prefs_.get(), unprotected_prefs_.get(),
unprotected_pref_hash_store_.get(), &protected_prefs_need_cleanup,
&unprotected_prefs_altered);
bool unprotected_prefs_need_cleanup = false;
bool protected_prefs_altered = false;
MigratePrefsFromOldToNewStore(
protected_pref_names_, unprotected_prefs_.get(), protected_prefs_.get(),
protected_pref_hash_store_.get(), &unprotected_prefs_need_cleanup,
&protected_prefs_altered);
if (!unprotected_prefs_altered && !protected_prefs_altered) {
// Clean up any MACs that might have been previously migrated from the
// various stores. It's safe to leave them behind for a little while as they
// will be ignored unless the corresponding value is _also_ present. The
// cleanup must be deferred until the MACs have been written to their target
// stores, and doing so in a subsequent launch is easier than within the
// same process.
CleanupMigratedHashes(unprotected_pref_names_,
protected_pref_hash_store_.get(),
protected_prefs_.get());
CleanupMigratedHashes(protected_pref_names_,
unprotected_pref_hash_store_.get(),
unprotected_prefs_.get());
}
// Hand the processed prefs back to their respective filters.
std::move(finalize_unprotected_filter_on_load_)
.Run(std::move(unprotected_prefs_), unprotected_prefs_altered);
std::move(finalize_protected_filter_on_load_)
.Run(std::move(protected_prefs_), protected_prefs_altered);
if (unprotected_prefs_need_cleanup) {
// Schedule a cleanup of the |protected_pref_names_| from the unprotected
// prefs once the protected prefs were successfully written to disk (or
// do it immediately if |!protected_prefs_altered|).
ScheduleSourcePrefStoreCleanup(
register_on_successful_protected_store_write_callback_,
unprotected_store_cleaner_, protected_pref_names_,
protected_prefs_altered);
}
if (protected_prefs_need_cleanup) {
// Schedule a cleanup of the |unprotected_pref_names_| from the protected
// prefs once the unprotected prefs were successfully written to disk (or
// do it immediately if |!unprotected_prefs_altered|).
ScheduleSourcePrefStoreCleanup(
register_on_successful_unprotected_store_write_callback_,
protected_store_cleaner_, unprotected_pref_names_,
unprotected_prefs_altered);
}
}
} // namespace
void SetupTrackedPreferencesMigration(
const std::set<std::string>& unprotected_pref_names,
const std::set<std::string>& protected_pref_names,
const base::RepeatingCallback<void(const std::string& key)>&
unprotected_store_cleaner,
const base::RepeatingCallback<void(const std::string& key)>&
protected_store_cleaner,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_unprotected_store_write_callback,
const base::RepeatingCallback<void(base::OnceClosure)>&
register_on_successful_protected_store_write_callback,
std::unique_ptr<PrefHashStore> unprotected_pref_hash_store,
std::unique_ptr<PrefHashStore> protected_pref_hash_store,
InterceptablePrefFilter* unprotected_pref_filter,
InterceptablePrefFilter* protected_pref_filter) {
auto prefs_migrator = base::MakeRefCounted<TrackedPreferencesMigrator>(
unprotected_pref_names, protected_pref_names, unprotected_store_cleaner,
protected_store_cleaner,
register_on_successful_unprotected_store_write_callback,
register_on_successful_protected_store_write_callback,
std::move(unprotected_pref_hash_store),
std::move(protected_pref_hash_store), unprotected_pref_filter,
protected_pref_filter);
// The callbacks bound below will own this TrackedPreferencesMigrator by
// reference.
unprotected_pref_filter->InterceptNextFilterOnLoad(base::BindOnce(
&TrackedPreferencesMigrator::InterceptFilterOnLoad, prefs_migrator,
TrackedPreferencesMigrator::UNPROTECTED_PREF_FILTER));
protected_pref_filter->InterceptNextFilterOnLoad(base::BindOnce(
&TrackedPreferencesMigrator::InterceptFilterOnLoad, prefs_migrator,
TrackedPreferencesMigrator::PROTECTED_PREF_FILTER));
}