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/*
* Copyright (C) 2019 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.
*/
#define LOG_TAG "Stability"
#include <binder/Stability.h>
#include <binder/BpBinder.h>
#include <binder/Binder.h>
namespace android {
namespace internal {
void Stability::forceDowngradeToStability(const sp<IBinder>& binder, Level level) {
// Downgrading a remote binder would require also copying the version from
// the binder sent here. In practice though, we don't need to downgrade the
// stability of a remote binder, since this would as an effect only restrict
// what we can do to it.
LOG_ALWAYS_FATAL_IF(!binder || !binder->localBinder(), "Can only downgrade local binder");
status_t result = setRepr(binder.get(), level, REPR_LOG | REPR_ALLOW_DOWNGRADE);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
void Stability::forceDowngradeToLocalStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, getLocalLevel());
}
void Stability::forceDowngradeToSystemStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, Level::SYSTEM);
}
void Stability::forceDowngradeToVendorStability(const sp<IBinder>& binder) {
forceDowngradeToStability(binder, Level::VENDOR);
}
void Stability::markCompilationUnit(IBinder* binder) {
status_t result = setRepr(binder, getLocalLevel(), REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
void Stability::markVintf(IBinder* binder) {
status_t result = setRepr(binder, Level::VINTF, REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
std::string Stability::debugToString(const sp<IBinder>& binder) {
return levelString(getRepr(binder.get()));
}
void Stability::markVndk(IBinder* binder) {
status_t result = setRepr(binder, Level::VENDOR, REPR_LOG);
LOG_ALWAYS_FATAL_IF(result != OK, "Should only mark known object.");
}
bool Stability::requiresVintfDeclaration(const sp<IBinder>& binder) {
return check(getRepr(binder.get()), Level::VINTF);
}
void Stability::tryMarkCompilationUnit(IBinder* binder) {
(void)setRepr(binder, getLocalLevel(), REPR_NONE);
}
Stability::Level Stability::getLocalLevel() {
#ifdef __ANDROID_APEX__
#error APEX can't use libbinder (must use libbinder_ndk)
#endif
#ifdef __ANDROID_VNDK__
return Level::VENDOR;
#else
// TODO(b/139325195): split up stability levels for system/APEX.
return Level::SYSTEM;
#endif
}
status_t Stability::setRepr(IBinder* binder, int32_t setting, uint32_t flags) {
bool log = flags & REPR_LOG;
bool allowDowngrade = flags & REPR_ALLOW_DOWNGRADE;
int16_t current = getRepr(binder);
// null binder is always written w/ 'UNDECLARED' stability
if (binder == nullptr) {
if (setting == UNDECLARED) {
return OK;
} else {
if (log) {
ALOGE("Null binder written with stability %s.", levelString(setting).c_str());
}
return BAD_TYPE;
}
}
if (!isDeclaredLevel(setting)) {
if (log) {
ALOGE("Can only set known stability, not %d.", setting);
}
return BAD_TYPE;
}
Level levelSetting = static_cast<Level>(setting);
if (current == setting) return OK;
bool hasAlreadyBeenSet = current != Level::UNDECLARED;
bool isAllowedDowngrade = allowDowngrade && check(current, levelSetting);
if (hasAlreadyBeenSet && !isAllowedDowngrade) {
if (log) {
ALOGE("Interface being set with %s but it is already marked as %s",
levelString(setting).c_str(), levelString(current).c_str());
}
return BAD_TYPE;
}
if (isAllowedDowngrade) {
ALOGI("Interface set with %s downgraded to %s stability", levelString(current).c_str(),
levelString(setting).c_str());
}
BBinder* local = binder->localBinder();
if (local != nullptr) {
local->mStability = setting;
} else {
binder->remoteBinder()->mStability = setting;
}
return OK;
}
int16_t Stability::getRepr(IBinder* binder) {
if (binder == nullptr) {
return Level::UNDECLARED;
}
BBinder* local = binder->localBinder();
if (local != nullptr) {
return local->mStability;
}
return binder->remoteBinder()->mStability;
}
bool Stability::check(int16_t provided, Level required) {
bool stable = (provided & required) == required;
if (provided != UNDECLARED && !isDeclaredLevel(provided)) {
ALOGE("Unknown stability when checking interface stability %d.", provided);
stable = false;
}
return stable;
}
bool Stability::isDeclaredLevel(int32_t stability) {
return stability == VENDOR || stability == SYSTEM || stability == VINTF;
}
std::string Stability::levelString(int32_t level) {
switch (level) {
case Level::UNDECLARED: return "undeclared stability";
case Level::VENDOR: return "vendor stability";
case Level::SYSTEM: return "system stability";
case Level::VINTF: return "vintf stability";
}
return "unknown stability " + std::to_string(level);
}
} // namespace internal
} // namespace stability
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