1 files changed, 13 insertions, 108 deletions

diff --git a/libs/binder/include/binder/Stability.h b/libs/binder/include/binder/Stability.h
index f4bfac890a..2894482f55 100644
--- a/libs/binder/include/binder/Stability.h
+++ b/libs/binder/include/binder/Stability.h
@@ -26,65 +26,10 @@ class ProcessState;
 
 namespace internal {
 
-// Stability encodes how a binder changes over time. There are two levels of
-// stability:
-// 1). the interface stability - this is how a particular set of API calls (a
-//   particular ordering of things like writeInt32/readInt32) are changed over
-//   time. If one release, we have 'writeInt32' and the next release, we have
-//   'writeInt64', then this interface doesn't have a very stable
-//   Stability::Level. Usually this ordering is controlled by a .aidl file.
-// 2). the wire format stability - this is how these API calls map to actual
-//   bytes that are written to the wire (literally, this is how they are written
-//   to the kernel inside of IBinder::transact, but it may be expanded to other
-//   wires in the future). For instance, writeInt32 in binder translates to
-//   writing a 4-byte little-endian integer in two's complement. You can imagine
-//   in the future, we change writeInt32/readInt32 to instead write 8-bytes with
-//   that integer and some check bits. In this case, the wire format changes,
-//   but as long as a client libbinder knows to keep on writing a 4-byte value
-//   to old servers, and new servers know how to interpret the 8-byte result,
-//   they can still communicate.
-//
-// Every binder object has a stability level associated with it, and when
-// communicating with a binder, we make sure that the command we sent is one
-// that it knows how to process. The summary of stability of a binder is
-// represented by a Stability::Category object.
-
+// WARNING: These APIs are only ever expected to be called by auto-generated code.
+//     Instead of calling them, you should set the stability of a .aidl interface
 class Stability final {
 public:
-    // Given a binder interface at a certain stability, there may be some
-    // requirements associated with that higher stability level. For instance, a
-    // VINTF stability binder is required to be in the VINTF manifest. This API
-    // can be called to use that same interface within the local partition.
-    static void forceDowngradeToLocalStability(const sp<IBinder>& binder);
-
-    // WARNING: Below APIs are only ever expected to be called by auto-generated code.
-    //     Instead of calling them, you should set the stability of a .aidl interface
-
-    // WARNING: The only client of
-    //      - forceDowngradeToSystemStability() and;
-    //      - korceDowngradeToVendorStability()
-    //  should be AIBinder_forceDowngradeToLocalStability().
-    //
-    // getLocalLevel() in libbinder returns Level::SYSTEM when called
-    // from libbinder_ndk (even on vendor partition). So we explicitly provide
-    // these methods for use by the NDK API:
-    //      AIBinder_forceDowngradeToLocalStability().
-    //
-    // This allows correctly downgrading the binder's stability to either system/vendor,
-    // depending on the partition.
-
-    // Given a binder interface at a certain stability, there may be some
-    // requirements associated with that higher stability level. For instance, a
-    // VINTF stability binder is required to be in the VINTF manifest. This API
-    // can be called to use that same interface within the vendor partition.
-    static void forceDowngradeToVendorStability(const sp<IBinder>& binder);
-
-    // Given a binder interface at a certain stability, there may be some
-    // requirements associated with that higher stability level. For instance, a
-    // VINTF stability binder is required to be in the VINTF manifest. This API
-    // can be called to use that same interface within the system partition.
-    static void forceDowngradeToSystemStability(const sp<IBinder>& binder);
-
     // WARNING: This is only ever expected to be called by auto-generated code. You likely want to
     // change or modify the stability class of the interface you are using.
     // This must be called as soon as the binder in question is constructed. No thread safety
@@ -128,7 +73,7 @@ private:
 
     static void tryMarkCompilationUnit(IBinder* binder);
 
-    enum Level : uint8_t {
+    enum Level : int32_t {
         UNDECLARED = 0,
 
         VENDOR = 0b000011,
@@ -136,62 +81,22 @@ private:
         VINTF = 0b111111,
     };
 
-    // This is the format of stability passed on the wire.
-    struct Category {
-        static inline Category fromRepr(int32_t representation) {
-            return *reinterpret_cast<Category*>(&representation);
-        }
-        int32_t repr() const {
-            return *reinterpret_cast<const int32_t*>(this);
-        }
-        static inline Category currentFromLevel(Level level);
-
-        bool operator== (const Category& o) const {
-            return repr() == o.repr();
-        }
-        bool operator!= (const Category& o) const {
-            return !(*this == o);
-        }
-
-        std::string debugString();
-
-        // This is the version of the wire protocol associated with the host
-        // process of a particular binder. As the wire protocol changes, if
-        // sending a transaction to a binder with an old version, the Parcel
-        // class must write parcels according to the version documented here.
-        uint8_t version;
-
-        uint8_t reserved[2];
-
-        // bitmask of Stability::Level
-        Level level;
-    };
-    static_assert(sizeof(Category) == sizeof(int32_t));
-
-    // returns the stability according to how this was built
-    static Level getLocalLevel();
-
-    // Downgrades binder stability to the specified level.
-    static void forceDowngradeToStability(const sp<IBinder>& binder, Level level);
+#if defined(__ANDROID_VNDK__) && !defined(__ANDROID_APEX__)
+    static constexpr Level kLocalStability = Level::VENDOR;
+#else
+    static constexpr Level kLocalStability = Level::SYSTEM;
+#endif
 
-    enum {
-      REPR_NONE = 0,
-      REPR_LOG = 1,
-      REPR_ALLOW_DOWNGRADE = 2,
-    };
     // applies stability to binder if stability level is known
     __attribute__((warn_unused_result))
-    static status_t setRepr(IBinder* binder, int32_t representation, uint32_t flags);
+    static status_t set(IBinder* binder, int32_t stability, bool log);
 
-    // get stability information as encoded on the wire
-    static Category getCategory(IBinder* binder);
+    static Level get(IBinder* binder);
 
-    // whether a transaction on binder is allowed, if the transaction
-    // is done from a context with a specific stability level
-    static bool check(Category provided, Level required);
+    static bool check(int32_t provided, Level required);
 
-    static bool isDeclaredLevel(Level level);
-    static std::string levelString(Level level);
+    static bool isDeclaredStability(int32_t stability);
+    static std::string stabilityString(int32_t stability);
 
     Stability();
 };