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// Copyright 2025 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/persistent_cache/sqlite/vfs/sqlite_sandboxed_vfs.h"
#include <mutex>
#include <optional>
#include <utility>
#include "base/files/file.h"
#include "base/files/file_util.h"
#include "base/synchronization/lock.h"
#include "sql/sandboxed_vfs.h"
#include "sql/sandboxed_vfs_file.h"
#include "third_party/sqlite/sqlite3.h"
namespace persistent_cache {
namespace {
std::once_flag g_register_vfs_once_flag;
SqliteSandboxedVfsDelegate* g_instance = nullptr;
} // namespace
SqliteSandboxedVfsDelegate::SqliteSandboxedVfsDelegate() {
CHECK(!g_instance);
g_instance = this;
}
SqliteSandboxedVfsDelegate::~SqliteSandboxedVfsDelegate() {
CHECK_EQ(this, g_instance);
g_instance = nullptr;
}
// static
SqliteSandboxedVfsDelegate* SqliteSandboxedVfsDelegate::GetInstance() {
// When requesting the the global instance the first time make sure it exists
// and register it.
std::call_once(g_register_vfs_once_flag, []() {
sql::SandboxedVfs::Register(kSqliteVfsName,
std::make_unique<SqliteSandboxedVfsDelegate>(),
/*make_default=*/false);
});
return g_instance;
}
sql::SandboxedVfsFile* SqliteSandboxedVfsDelegate::RetrieveSandboxedVfsFile(
base::File file,
base::FilePath file_path,
sql::SandboxedVfsFileType file_type,
sql::SandboxedVfs* vfs) {
base::AutoLock lock(files_map_lock_);
auto it = sandboxed_files_map_.find(file_path);
if (it == sandboxed_files_map_.end()) {
return nullptr;
}
it->second->OnFileOpened(std::move(file));
return it->second;
}
base::File SqliteSandboxedVfsDelegate::OpenFile(
const base::FilePath& file_path,
int /*sqlite_requested_flags*/) {
base::AutoLock lock(files_map_lock_);
// If `file_name` is missing in the mapping there is no file to return.
auto it = sandboxed_files_map_.find(file_path);
if (it == sandboxed_files_map_.end()) {
return base::File();
}
// If `file_name` is found in the mapping return the associated file.
return it->second->TakeUnderlyingFile();
}
int SqliteSandboxedVfsDelegate::DeleteFile(const base::FilePath& file_path,
bool /*sync_dir*/) {
base::AutoLock lock(files_map_lock_);
// Sandboxed processes are not capable of deleting files. This completely
// prevents databases using SqliteSandboxedVfsDelegate from using
// `sql::Database::Delete()`.
auto it = sandboxed_files_map_.find(file_path);
if (it != sandboxed_files_map_.end()) {
return SQLITE_IOERR_DELETE;
}
return SQLITE_NOTFOUND;
}
std::optional<sql::SandboxedVfs::PathAccessInfo>
SqliteSandboxedVfsDelegate::GetPathAccess(const base::FilePath& file_path) {
base::AutoLock lock(files_map_lock_);
// If `file_name` is missing in the mapping there is no access to return.
auto it = sandboxed_files_map_.find(file_path);
if (it == sandboxed_files_map_.end()) {
return std::nullopt;
}
// The files will never be received without read access.
// Write access is conditional on the file being opened for write.
return sql::SandboxedVfs::PathAccessInfo{
.can_read = true,
.can_write = it->second->access_rights() ==
SandboxedFile::AccessRights::kReadWrite};
}
SqliteSandboxedVfsDelegate::UnregisterRunner::UnregisterRunner(
const SqliteVfsFileSet& vfs_file_set)
: vfs_file_set_(vfs_file_set) {}
SqliteSandboxedVfsDelegate::UnregisterRunner::~UnregisterRunner() {
SqliteSandboxedVfsDelegate::GetInstance()->UnregisterSandboxedFiles(
*vfs_file_set_);
}
// static
void SqliteSandboxedVfsDelegate::UnregisterSandboxedFiles(
const SqliteVfsFileSet& sqlite_vfs_file_set) {
base::AutoLock lock(files_map_lock_);
for (auto& kv : sqlite_vfs_file_set.GetFiles()) {
size_t num_erased = sandboxed_files_map_.erase(kv.first);
CHECK_EQ(num_erased, 1ull)
<< "Unregistering the same file set more than once should never happen";
}
}
// static
SqliteSandboxedVfsDelegate::UnregisterRunner
SqliteSandboxedVfsDelegate::RegisterSandboxedFiles(
const SqliteVfsFileSet& sqlite_vfs_file_set) {
base::AutoLock lock(files_map_lock_);
for (auto& kv : sqlite_vfs_file_set.GetFiles()) {
auto [it, inserted] = sandboxed_files_map_.emplace(kv.first, kv.second);
CHECK(inserted)
<< "Registering the same file set more than once should never happen";
}
return UnregisterRunner(sqlite_vfs_file_set);
}
} // namespace persistent_cache
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