storage_partition_impl_map.cc | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/storage_partition_impl_map.h"

#include <unordered_set>
#include <utility>

#include "base/barrier_closure.h"
#include "base/command_line.h"
#include "base/containers/contains.h"
#include "base/containers/map_util.h"
#include "base/files/file_enumerator.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/functional/callback_helpers.h"
#include "base/location.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/task/single_thread_task_runner.h"
#include "base/task/thread_pool.h"
#include "build/build_config.h"
#include "content/browser/background_fetch/background_fetch_context.h"
#include "content/browser/blob_storage/chrome_blob_storage_context.h"
#include "content/browser/code_cache/generated_code_cache_context.h"
#include "content/browser/cookie_store/cookie_store_manager.h"
#include "content/browser/file_system/browser_file_system_helper.h"
#include "content/browser/loader/subresource_proxying_url_loader_service.h"
#include "content/browser/resource_context_impl.h"
#include "content/browser/storage_partition_impl.h"
#include "content/browser/webui/url_data_manager_backend.h"
#include "content/public/browser/browser_context.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/browser/storage_partition.h"
#include "content/public/common/content_client.h"
#include "content/public/common/content_features.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/url_constants.h"
#include "crypto/sha2.h"
#include "services/network/public/cpp/features.h"
#include "storage/browser/blob/blob_storage_context.h"
#include "storage/browser/database/database_tracker.h"
#include "third_party/blink/public/common/storage_key/storage_key.h"

namespace content {

namespace {

// These constants are used to create the directory structure under the profile
// where renderers with a non-default storage partition keep their persistent
// state. This will contain a set of directories that partially mirror the
// directory structure of BrowserContext::GetPath().
//
// The kStoragePartitionDirname contains an extensions directory which is
// further partitioned by extension id, followed by another level of directories
// for the "default" extension storage partition and one directory for each
// persistent partition used by a webview tag. Example:
//
//   Storage/ext/ABCDEF/def
//   Storage/ext/ABCDEF/hash(partition name)
//
// The code in GetStoragePartitionPath() constructs these path names.
//
// TODO(nasko): Move extension related path code out of content.
const base::FilePath::CharType kStoragePartitionDirname[] = …);
const base::FilePath::CharType kExtensionsDirname[] = …);
const base::FilePath::CharType kDefaultPartitionDirname[] = …);
const base::FilePath::CharType kTrashDirname[] = …);

// Because partition names are user specified, they can be arbitrarily long
// which makes them unsuitable for paths names. We use a truncation of a
// SHA256 hash to perform a deterministic shortening of the string. The
// kPartitionNameHashBytes constant controls the length of the truncation.
// We use 6 bytes, which gives us 99.999% reliability against collisions over
// 1 million partition domains.
//
// Analysis:
// We assume that all partition names within one partition domain are
// controlled by the the same entity. Thus there is no chance for adverserial
// attack and all we care about is accidental collision. To get 5 9s over
// 1 million domains, we need the probability of a collision in any one domain
// to be
//
//    p < nroot(1000000, .99999) ~= 10^-11
//
// We use the following birthday attack approximation to calculate the max
// number of unique names for this probability:
//
//    n(p,H) = sqrt(2*H * ln(1/(1-p)))
//
// For a 6-byte hash, H = 2^(6*8).  n(10^-11, H) ~= 75
//
// An average partition domain is likely to have less than 10 unique
// partition names which is far lower than 75.
//
// Note, that for 4 9s of reliability, the limit is 237 partition names per
// partition domain.
const int kPartitionNameHashBytes = …;

// Needed for selecting all files in ObliterateOneDirectory() below.
#if BUILDFLAG(IS_POSIX)
const int kAllFileTypes = …;
#else
const int kAllFileTypes = base::FileEnumerator::FILES |
                          base::FileEnumerator::DIRECTORIES;
#endif

base::FilePath GetStoragePartitionDomainPath(
    const std::string& partition_domain) { … }

// Helper function for doing a depth-first deletion of the data on disk.
// Examines paths directly in |current_dir| (no recursion) and tries to
// delete from disk anything that is in, or isn't a parent of something in
// |paths_to_keep|. Paths that need further expansion are added to
// |paths_to_consider|.
void ObliterateOneDirectory(const base::FilePath& current_dir,
                            const std::vector<base::FilePath>& paths_to_keep,
                            std::vector<base::FilePath>* paths_to_consider) { … }

// Synchronously attempts to delete |unnormalized_root|, preserving only
// entries in |paths_to_keep|. If there are no entries in |paths_to_keep| on
// disk, then it completely removes |unnormalized_root|. All paths must be
// absolute paths.
void BlockingObliteratePath(
    const base::FilePath& unnormalized_browser_context_root,
    const base::FilePath& unnormalized_root,
    const std::vector<base::FilePath>& paths_to_keep,
    const scoped_refptr<base::TaskRunner>& closure_runner,
    base::OnceClosure on_gc_required) { … }

// Ensures each path in |active_paths| is a direct child of storage_root.
void NormalizeActivePaths(const base::FilePath& storage_root,
                          std::unordered_set<base::FilePath>* active_paths) { … }

// Deletes all entries inside the |storage_root| that are not in the
// |active_paths|.  Deletion is done in 2 steps:
//
//   (1) Moving all garbage collected paths into a trash directory.
//   (2) Asynchronously deleting the trash directory.
//
// The deletion is asynchronous because after (1) completes, calling code can
// safely continue to use the paths that had just been garbage collected
// without fear of race conditions.
//
// This code also ignores failed moves rather than attempting a smarter retry.
// Moves shouldn't fail here unless there is some out-of-band error (eg.,
// FS corruption). Retry logic is dangerous in the general case because
// there is not necessarily a guaranteed case where the logic may succeed.
//
// This function is still named BlockingGarbageCollect() because it does
// execute a few filesystem operations synchronously.
void BlockingGarbageCollect(
    const base::FilePath& storage_root,
    const scoped_refptr<base::TaskRunner>& file_access_runner,
    std::unordered_set<base::FilePath> active_paths) { … }

}  // namespace

// static
base::FilePath StoragePartitionImplMap::GetStoragePartitionPath(
    const std::string& partition_domain,
    const std::string& partition_name) { … }

StoragePartitionImplMap::StoragePartitionImplMap(
    BrowserContext* browser_context)
    : … { … }

StoragePartitionImplMap::~StoragePartitionImplMap() { … }

StoragePartitionImpl* StoragePartitionImplMap::Get(
    const StoragePartitionConfig& partition_config,
    bool can_create) { … }

void StoragePartitionImplMap::AsyncObliterate(
    const std::string& partition_domain,
    base::OnceClosure on_gc_required,
    base::OnceClosure done_callback) { … }

void StoragePartitionImplMap::GarbageCollect(
    std::unordered_set<base::FilePath> active_paths,
    base::OnceClosure done) { … }

void StoragePartitionImplMap::ForEach(
    base::FunctionRef<void(StoragePartition*)> fn) { … }

void StoragePartitionImplMap::PostCreateInitialization(
    StoragePartitionImpl* partition,
    bool in_memory) { … }

}  // namespace content
chromium/content/browser/storage_partition_impl_map.cc
