// 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 "base/test/test_file_util.h"
#include <windows.h>
#include <aclapi.h>
#include <sddl.h>
#include <stddef.h>
#include <wchar.h>
#include <memory>
#include "base/check_op.h"
#include "base/files/file_path.h"
#include "base/files/file_util.h"
#include "base/memory/ptr_util.h"
#include "base/notreached.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/threading/platform_thread.h"
#include "base/win/scoped_handle.h"
#include "base/win/scoped_localalloc.h"
#include "base/win/shlwapi.h"
namespace base {
namespace {
struct PermissionInfo {
PSECURITY_DESCRIPTOR security_descriptor;
ACL dacl;
};
// Gets a blob indicating the permission information for |path|.
// |length| is the length of the blob. Zero on failure.
// Returns the blob pointer, or NULL on failure.
void* GetPermissionInfo(const FilePath& path, size_t* length) {
DCHECK(length);
*length = 0;
PACL dacl = nullptr;
PSECURITY_DESCRIPTOR security_descriptor;
if (GetNamedSecurityInfo(path.value().c_str(), SE_FILE_OBJECT,
DACL_SECURITY_INFORMATION, nullptr, nullptr, &dacl,
nullptr, &security_descriptor) != ERROR_SUCCESS) {
return nullptr;
}
DCHECK(dacl);
*length = sizeof(PSECURITY_DESCRIPTOR) + dacl->AclSize;
PermissionInfo* info = reinterpret_cast<PermissionInfo*>(new char[*length]);
info->security_descriptor = security_descriptor;
memcpy(&info->dacl, dacl, dacl->AclSize);
return info;
}
// Restores the permission information for |path|, given the blob retrieved
// using |GetPermissionInfo()|.
// |info| is the pointer to the blob.
// |length| is the length of the blob.
// Either |info| or |length| may be NULL/0, in which case nothing happens.
bool RestorePermissionInfo(const FilePath& path, void* info, size_t length) {
if (!info || !length)
return false;
PermissionInfo* perm = reinterpret_cast<PermissionInfo*>(info);
DWORD rc = SetNamedSecurityInfo(const_cast<wchar_t*>(path.value().c_str()),
SE_FILE_OBJECT, DACL_SECURITY_INFORMATION,
nullptr, nullptr, &perm->dacl, nullptr);
LocalFree(perm->security_descriptor);
char* char_array = reinterpret_cast<char*>(info);
delete [] char_array;
return rc == ERROR_SUCCESS;
}
std::unique_ptr<wchar_t[]> ToCStr(const std::basic_string<wchar_t>& str) {
size_t size = str.size() + 1;
std::unique_ptr<wchar_t[]> ptr = std::make_unique<wchar_t[]>(size);
wcsncpy(ptr.get(), str.c_str(), size);
return ptr;
}
} // namespace
bool DieFileDie(const FilePath& file, bool recurse) {
// It turns out that to not induce flakiness a long timeout is needed.
const int kIterations = 25;
const TimeDelta kTimeout = Seconds(10) / kIterations;
if (!PathExists(file))
return true;
// Sometimes Delete fails, so try a few more times. Divide the timeout
// into short chunks, so that if a try succeeds, we won't delay the test
// for too long.
for (int i = 0; i < kIterations; ++i) {
bool success;
if (recurse)
success = DeletePathRecursively(file);
else
success = DeleteFile(file);
if (success)
return true;
PlatformThread::Sleep(kTimeout);
}
return false;
}
void SyncPageCacheToDisk() {
// Approximating this with noop. The proper implementation would require
// administrator privilege:
// https://docs.microsoft.com/en-us/windows/desktop/api/FileAPI/nf-fileapi-flushfilebuffers
}
bool EvictFileFromSystemCache(const FilePath& file) {
FilePath::StringType file_value = file.value();
if (file_value.length() >= MAX_PATH && file.IsAbsolute()) {
file_value.insert(0, L"\\\\?\\");
}
win::ScopedHandle file_handle(
CreateFile(file_value.c_str(), GENERIC_READ | GENERIC_WRITE, 0, nullptr,
OPEN_EXISTING, FILE_FLAG_NO_BUFFERING, nullptr));
if (!file_handle.is_valid())
return false;
// Re-write the file time information to trigger cache eviction for the file.
// This function previously overwrote the entire file without buffering, but
// local experimentation validates this simplified and *much* faster approach:
// [1] Sysinternals RamMap no longer lists these files as cached afterwards.
// [2] Telemetry performance test startup.cold.blank_page reports sane values.
BY_HANDLE_FILE_INFORMATION bhi = {0};
CHECK(::GetFileInformationByHandle(file_handle.get(), &bhi));
CHECK(::SetFileTime(file_handle.get(), &bhi.ftCreationTime,
&bhi.ftLastAccessTime, &bhi.ftLastWriteTime));
return true;
}
// Deny |permission| on the file |path|, for the current user.
bool DenyFilePermission(const FilePath& path, DWORD permission) {
PACL old_dacl;
PSECURITY_DESCRIPTOR security_descriptor;
std::unique_ptr<TCHAR[]> path_ptr = ToCStr(path.value().c_str());
if (GetNamedSecurityInfo(path_ptr.get(), SE_FILE_OBJECT,
DACL_SECURITY_INFORMATION, nullptr, nullptr,
&old_dacl, nullptr,
&security_descriptor) != ERROR_SUCCESS) {
return false;
}
std::unique_ptr<TCHAR[]> current_user = ToCStr(std::wstring(L"CURRENT_USER"));
EXPLICIT_ACCESS new_access = {
permission,
DENY_ACCESS,
0,
{nullptr, NO_MULTIPLE_TRUSTEE, TRUSTEE_IS_NAME, TRUSTEE_IS_USER,
current_user.get()}};
PACL new_dacl;
if (SetEntriesInAcl(1, &new_access, old_dacl, &new_dacl) != ERROR_SUCCESS) {
LocalFree(security_descriptor);
return false;
}
DWORD rc = SetNamedSecurityInfo(path_ptr.get(), SE_FILE_OBJECT,
DACL_SECURITY_INFORMATION, nullptr, nullptr,
new_dacl, nullptr);
LocalFree(security_descriptor);
LocalFree(new_dacl);
return rc == ERROR_SUCCESS;
}
bool MakeFileUnreadable(const FilePath& path) {
return DenyFilePermission(path, GENERIC_READ);
}
bool MakeFileUnwritable(const FilePath& path) {
return DenyFilePermission(path, GENERIC_WRITE);
}
FilePermissionRestorer::FilePermissionRestorer(const FilePath& path)
: path_(path), info_(nullptr), length_(0) {
info_ = GetPermissionInfo(path_, &length_);
DCHECK(info_);
DCHECK_NE(0u, length_);
}
FilePermissionRestorer::~FilePermissionRestorer() {
if (!RestorePermissionInfo(path_, info_, length_))
NOTREACHED();
}
std::wstring GetFileDacl(const FilePath& path) {
PSECURITY_DESCRIPTOR sd;
if (::GetNamedSecurityInfo(path.value().c_str(), SE_FILE_OBJECT,
DACL_SECURITY_INFORMATION, nullptr, nullptr,
nullptr, nullptr, &sd) != ERROR_SUCCESS) {
return std::wstring();
}
auto sd_ptr = win::TakeLocalAlloc(sd);
LPWSTR sddl;
if (!::ConvertSecurityDescriptorToStringSecurityDescriptor(
sd_ptr.get(), SDDL_REVISION_1, DACL_SECURITY_INFORMATION, &sddl,
nullptr)) {
return std::wstring();
}
return win::TakeLocalAlloc(sddl).get();
}
bool CreateWithDacl(const FilePath& path, wcstring_view sddl, bool directory) {
PSECURITY_DESCRIPTOR sd;
if (!::ConvertStringSecurityDescriptorToSecurityDescriptor(
sddl.c_str(), SDDL_REVISION_1, &sd, nullptr)) {
return false;
}
auto sd_ptr = win::TakeLocalAlloc(sd);
SECURITY_ATTRIBUTES security_attr = {};
security_attr.nLength = sizeof(security_attr);
security_attr.lpSecurityDescriptor = sd_ptr.get();
if (directory) {
return !!::CreateDirectory(path.value().c_str(), &security_attr);
}
return win::ScopedHandle(::CreateFile(path.value().c_str(), GENERIC_ALL, 0,
&security_attr, CREATE_ALWAYS, 0,
nullptr))
.is_valid();
}
} // namespace base
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