libbinder_ndk: read/write ParcelFileDescriptor

Bug: 115607973
Test: atest android.binder.cts
Change-Id: Ic9ef70cba95a12f3765573d24d87fd15021ab7a9

4 files changed, 73 insertions, 12 deletions

diff --git a/libs/binder/ndk/include_ndk/android/binder_auto_utils.h b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
index cc0a29d18a..e52a1d69ae 100644
--- a/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
+++ b/libs/binder/ndk/include_ndk/android/binder_auto_utils.h
@@ -31,6 +31,7 @@
 #include <android/binder_status.h>
 
 #include <assert.h>
+#include <unistd.h>
 
 #ifdef __cplusplus
 
@@ -113,23 +114,23 @@ private:
 /**
  * This baseclass owns a single object, used to make various classes RAII.
  */
-template <typename T, void (*Destroy)(T*)>
+template <typename T, typename R, R (*Destroy)(T), T DEFAULT>
 class ScopedAResource {
 public:
     /**
      * Takes ownership of t.
      */
-    explicit ScopedAResource(T* t = nullptr) : mT(t) {}
+    explicit ScopedAResource(T t = DEFAULT) : mT(t) {}
 
     /**
      * This deletes the underlying object if it exists. See set.
      */
-    ~ScopedAResource() { set(nullptr); }
+    ~ScopedAResource() { set(DEFAULT); }
 
     /**
      * Takes ownership of t.
      */
-    void set(T* t) {
+    void set(T t) {
         Destroy(mT);
         mT = t;
     }
@@ -137,12 +138,12 @@ public:
     /**
      * This returns the underlying object to be modified but does not affect ownership.
      */
-    T* get() { return mT; }
+    T get() { return mT; }
 
     /**
      * This returns the const underlying object but does not affect ownership.
      */
-    const T* get() const { return mT; }
+    const T get() const { return mT; }
 
     /**
      * This allows the value in this class to be set from beneath it. If you call this method and
@@ -156,7 +157,7 @@ public:
      * Other usecases are discouraged.
      *
      */
-    T** getR() { return &mT; }
+    T* getR() { return &mT; }
 
     // copy-constructing, or move/copy assignment is disallowed
     ScopedAResource(const ScopedAResource&) = delete;
@@ -167,13 +168,13 @@ public:
     ScopedAResource(ScopedAResource&&) = default;
 
 private:
-    T* mT;
+    T mT;
 };
 
 /**
  * Convenience wrapper. See AParcel.
  */
-class ScopedAParcel : public ScopedAResource<AParcel, AParcel_delete> {
+class ScopedAParcel : public ScopedAResource<AParcel*, void, AParcel_delete, nullptr> {
 public:
     /**
      * Takes ownership of a.
@@ -186,7 +187,7 @@ public:
 /**
  * Convenience wrapper. See AStatus.
  */
-class ScopedAStatus : public ScopedAResource<AStatus, AStatus_delete> {
+class ScopedAStatus : public ScopedAResource<AStatus*, void, AStatus_delete, nullptr> {
 public:
     /**
      * Takes ownership of a.
@@ -205,7 +206,8 @@ public:
  * Convenience wrapper. See AIBinder_DeathRecipient.
  */
 class ScopedAIBinder_DeathRecipient
-      : public ScopedAResource<AIBinder_DeathRecipient, AIBinder_DeathRecipient_delete> {
+      : public ScopedAResource<AIBinder_DeathRecipient*, void, AIBinder_DeathRecipient_delete,
+                               nullptr> {
 public:
     /**
      * Takes ownership of a.
@@ -219,7 +221,8 @@ public:
 /**
  * Convenience wrapper. See AIBinder_Weak.
  */
-class ScopedAIBinder_Weak : public ScopedAResource<AIBinder_Weak, AIBinder_Weak_delete> {
+class ScopedAIBinder_Weak
+      : public ScopedAResource<AIBinder_Weak*, void, AIBinder_Weak_delete, nullptr> {
 public:
     /**
      * Takes ownership of a.
@@ -234,6 +237,19 @@ public:
     SpAIBinder promote() { return SpAIBinder(AIBinder_Weak_promote(get())); }
 };
 
+/**
+ * Convenience wrapper for a file descriptor.
+ */
+class ScopedFileDescriptor : public ScopedAResource<int, int, close, -1> {
+public:
+    /**
+     * Takes ownership of a.
+     */
+    explicit ScopedFileDescriptor(int a = -1) : ScopedAResource(a) {}
+    ~ScopedFileDescriptor() {}
+    ScopedFileDescriptor(ScopedFileDescriptor&&) = default;
+};
+
 } // namespace ndk
 
 #endif // __cplusplus
diff --git a/libs/binder/ndk/include_ndk/android/binder_parcel.h b/libs/binder/ndk/include_ndk/android/binder_parcel.h
index d36b3c06f3..0c0400180a 100644
--- a/libs/binder/ndk/include_ndk/android/binder_parcel.h
+++ b/libs/binder/ndk/include_ndk/android/binder_parcel.h
@@ -163,6 +163,23 @@ binder_status_t AParcel_readNullableStrongBinder(const AParcel* parcel, AIBinder
         __INTRODUCED_IN(29);
 
 /**
+ * Writes a file descriptor to the next location in a non-null parcel. This does not take ownership
+ * of fd.
+ *
+ * This corresponds to the SDK's android.os.ParcelFileDescriptor.
+ */
+binder_status_t AParcel_writeParcelFileDescriptor(AParcel* parcel, int fd);
+
+/**
+ * Reads an int from the next location in a non-null parcel.
+ *
+ * The returned fd must be closed.
+ *
+ * This corresponds to the SDK's android.os.ParcelFileDescriptor.
+ */
+binder_status_t AParcel_readParcelFileDescriptor(const AParcel* parcel, int* fd);
+
+/**
  * Writes an AStatus object to the next location in a non-null parcel.
  *
  * If the status is considered to be a low-level status and has no additional information other
diff --git a/libs/binder/ndk/libbinder_ndk.map.txt b/libs/binder/ndk/libbinder_ndk.map.txt
index f84814fa3c..ec6587a7e4 100644
--- a/libs/binder/ndk/libbinder_ndk.map.txt
+++ b/libs/binder/ndk/libbinder_ndk.map.txt
@@ -38,6 +38,7 @@ LIBBINDER_NDK { # introduced=29
     AParcel_readInt64;
     AParcel_readInt64Array;
     AParcel_readNullableStrongBinder;
+    AParcel_readParcelFileDescriptor;
     AParcel_readStatusHeader;
     AParcel_readString;
     AParcel_readStrongBinder;
@@ -59,6 +60,7 @@ LIBBINDER_NDK { # introduced=29
     AParcel_writeInt32Array;
     AParcel_writeInt64;
     AParcel_writeInt64Array;
+    AParcel_writeParcelFileDescriptor;
     AParcel_writeStatusHeader;
     AParcel_writeString;
     AParcel_writeStrongBinder;
diff --git a/libs/binder/ndk/parcel.cpp b/libs/binder/ndk/parcel.cpp
index 29094dba7b..ffa5caedba 100644
--- a/libs/binder/ndk/parcel.cpp
+++ b/libs/binder/ndk/parcel.cpp
@@ -23,13 +23,17 @@
 #include <limits>
 
 #include <android-base/logging.h>
+#include <android-base/unique_fd.h>
 #include <binder/Parcel.h>
+#include <binder/ParcelFileDescriptor.h>
 #include <utils/Unicode.h>
 
 using ::android::IBinder;
 using ::android::Parcel;
 using ::android::sp;
 using ::android::status_t;
+using ::android::base::unique_fd;
+using ::android::os::ParcelFileDescriptor;
 
 template <typename T>
 using ContiguousArrayGetter = T* (*)(void* arrayData);
@@ -218,6 +222,28 @@ binder_status_t AParcel_readNullableStrongBinder(const AParcel* parcel, AIBinder
     *binder = ret.get();
     return PruneStatusT(status);
 }
+
+binder_status_t AParcel_writeParcelFileDescriptor(AParcel* parcel, int fd) {
+    ParcelFileDescriptor parcelFd((unique_fd(fd)));
+
+    status_t status = parcel->get()->writeParcelable(parcelFd);
+
+    // ownership is retained by caller
+    (void)parcelFd.release().release();
+
+    return PruneStatusT(status);
+}
+
+binder_status_t AParcel_readParcelFileDescriptor(const AParcel* parcel, int* fd) {
+    ParcelFileDescriptor parcelFd;
+    // status_t status = parcelFd.readFromParcel(parcel->get());
+    status_t status = parcel->get()->readParcelable(&parcelFd);
+    if (status != STATUS_OK) return PruneStatusT(status);
+
+    *fd = parcelFd.release().release();
+    return STATUS_OK;
+}
+
 binder_status_t AParcel_writeStatusHeader(AParcel* parcel, const AStatus* status) {
     return PruneStatusT(status->get()->writeToParcel(parcel->get()));
 }