libartbase/base/file_utils.h

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef ART_LIBARTBASE_BASE_FILE_UTILS_H_
#define ART_LIBARTBASE_BASE_FILE_UTILS_H_

#include <stdlib.h>

#include <string>

#include <android-base/logging.h>

#include "arch/instruction_set.h"

namespace art {

static constexpr const char* kAndroidArtApexDefaultPath = "/apex/com.android.art";
static constexpr const char* kAndroidConscryptApexDefaultPath = "/apex/com.android.conscrypt";

// These methods return the Android Root, which is the historical location of
// the Android "system" directory, containing the built Android artifacts. On
// target, this is normally "/system". On host this is usually a directory under
// the build tree, e.g. "$ANDROID_BUILD_TOP/out/host/linux-x86". The location of
// the Android Root can be overriden using the ANDROID_ROOT environment
// variable.
//
// Find $ANDROID_ROOT, /system, or abort.
std::string GetAndroidRoot();
// Find $ANDROID_ROOT, /system, or return an empty string.
std::string GetAndroidRootSafe(/*out*/ std::string* error_msg);

// These methods return the ART Root, which is the location of the (activated)
// ART APEX module. On target, this is normally "/apex/com.android.art". On
// host, this is usually a subdirectory of the Android Root, e.g.
// "$ANDROID_BUILD_TOP/out/host/linux-x86/com.android.art". The location of the
// ART root can be overridden using the ANDROID_ART_ROOT environment variable.
//
// Find $ANDROID_ART_ROOT, /apex/com.android.art, or abort.
std::string GetArtRoot();
// Find $ANDROID_ART_ROOT, /apex/com.android.art, or return an empty string.
std::string GetArtRootSafe(/*out*/ std::string* error_msg);

// Return the path to the directory containing the ART binaries.
std::string GetArtBinDir();

// Find $ANDROID_DATA, /data, or abort.
std::string GetAndroidData();
// Find $ANDROID_DATA, /data, or return an empty string.
std::string GetAndroidDataSafe(/*out*/ std::string* error_msg);

// Returns the default boot image location (ANDROID_ROOT/framework/boot.art).
// Returns an empty string if ANDROID_ROOT is not set.
std::string GetDefaultBootImageLocation(std::string* error_msg);

// Returns the default boot image location, based on the passed android root.
std::string GetDefaultBootImageLocation(const std::string& android_root);

// Returns the dalvik-cache location, with subdir appended. Returns the empty string if the cache
// could not be found.
std::string GetDalvikCache(const char* subdir);

// Return true if we found the dalvik cache and stored it in the dalvik_cache argument.
// have_android_data will be set to true if we have an ANDROID_DATA that exists,
// dalvik_cache_exists will be true if there is a dalvik-cache directory that is present.
// The flag is_global_cache tells whether this cache is /data/dalvik-cache.
void GetDalvikCache(const char* subdir, bool create_if_absent, std::string* dalvik_cache,
                    bool* have_android_data, bool* dalvik_cache_exists, bool* is_global_cache);

// Returns the absolute dalvik-cache path for a DexFile or OatFile. The path returned will be
// rooted at cache_location.
bool GetDalvikCacheFilename(const char* file_location, const char* cache_location,
                            std::string* filename, std::string* error_msg);

// Returns the system location for an image
std::string GetSystemImageFilename(const char* location, InstructionSet isa);

// Returns the vdex filename for the given oat filename.
std::string GetVdexFilename(const std::string& oat_filename);

// Returns `filename` with the text after the last occurrence of '.' replaced with
// `extension`. If `filename` does not contain a period, returns a string containing `filename`,
// a period, and `new_extension`.
// Example: ReplaceFileExtension("foo.bar", "abc") == "foo.abc"
//          ReplaceFileExtension("foo", "abc") == "foo.abc"
std::string ReplaceFileExtension(const std::string& filename, const std::string& new_extension);

// Return whether the location is on /apex/com.android.art
bool LocationIsOnArtModule(const char* location);

// Return whether the location is on /apex/com.android.conscrypt
bool LocationIsOnConscryptModule(const char* location);

// Return whether the location is on system (i.e. android root).
bool LocationIsOnSystem(const char* location);

// Return whether the location is on system/framework (i.e. android_root/framework).
bool LocationIsOnSystemFramework(const char* location);

// Return whether the location is on /apex/.
bool LocationIsOnApex(const char* location);

// Compare the ART module root against android root. Returns true if they are
// both known and distinct. This is meant to be a proxy for 'running with apex'.
bool ArtModuleRootDistinctFromAndroidRoot();

// dup(2), except setting the O_CLOEXEC flag atomically, when possible.
int DupCloexec(int fd);

// Returns true if `path` begins with a slash.
inline bool IsAbsoluteLocation(const std::string& path) { return !path.empty() && path[0] == '/'; }

}  // namespace art

#endif  // ART_LIBARTBASE_BASE_FILE_UTILS_H_