libbinder: add getDebugPid

So that the PID of a service/binder can easily be looked up (for parity
w/ HIDL).

Bug: 141187318
Test: use w/ dumpsys
Change-Id: I29bf9acfe0cd1029d7aa2bb466b97347d46f2947

diff --git a/libs/binder/Binder.cpp b/libs/binder/Binder.cpp
index 693045e..34b6ea5 100644 (file)
--- a/libs/binder/Binder.cpp
+++ b/libs/binder/Binder.cpp
@@ -99,6 +99,32 @@ status_t IBinder::getExtension(sp<IBinder>* out) {
     return reply.readNullableStrongBinder(out);
 }
 
+status_t IBinder::getDebugPid(pid_t* out) {
+    BBinder* local = this->localBinder();
+    if (local != nullptr) {
+      *out = local->getDebugPid();
+      return OK;
+    }
+
+    BpBinder* proxy = this->remoteBinder();
+    LOG_ALWAYS_FATAL_IF(proxy == nullptr);
+
+    Parcel data;
+    Parcel reply;
+    status_t status = transact(DEBUG_PID_TRANSACTION, data, &reply);
+    if (status != OK) return status;
+
+    int32_t pid;
+    status = reply.readInt32(&pid);
+    if (status != OK) return status;
+
+    if (pid < 0 || pid > std::numeric_limits<pid_t>::max()) {
+        return BAD_VALUE;
+    }
+    *out = pid;
+    return OK;
+}
+
 // ---------------------------------------------------------------------------
 
 class BBinder::Extras
@@ -152,6 +178,9 @@ status_t BBinder::transact(
         case EXTENSION_TRANSACTION:
             err = reply->writeStrongBinder(getExtension());
             break;
+        case DEBUG_PID_TRANSACTION:
+            err = reply->writeInt32(getDebugPid());
+            break;
         default:
             err = onTransact(code, data, reply, flags);
             break;
@@ -250,6 +279,10 @@ sp<IBinder> BBinder::getExtension() {
     return e->mExtension;
 }
 
+pid_t BBinder::getDebugPid() {
+    return getpid();
+}
+
 void BBinder::setExtension(const sp<IBinder>& extension) {
     Extras* e = getOrCreateExtras();
     e->mExtension = extension;

diff --git a/libs/binder/include/binder/Binder.h b/libs/binder/include/binder/Binder.h
index 1095c7f..5673d5a 100644 (file)
--- a/libs/binder/include/binder/Binder.h
+++ b/libs/binder/include/binder/Binder.h
@@ -68,6 +68,8 @@ public:
     // This must be called before the object is sent to another process. Not thread safe.
     void                setExtension(const sp<IBinder>& extension);
 
+    pid_t               getDebugPid();
+
 protected:
     virtual             ~BBinder();
 

diff --git a/libs/binder/include/binder/IBinder.h b/libs/binder/include/binder/IBinder.h
index 027e088..b127234 100644 (file)
--- a/libs/binder/include/binder/IBinder.h
+++ b/libs/binder/include/binder/IBinder.h
@@ -59,6 +59,7 @@ public:
         INTERFACE_TRANSACTION   = B_PACK_CHARS('_', 'N', 'T', 'F'),
         SYSPROPS_TRANSACTION    = B_PACK_CHARS('_', 'S', 'P', 'R'),
         EXTENSION_TRANSACTION   = B_PACK_CHARS('_', 'E', 'X', 'T'),
+        DEBUG_PID_TRANSACTION   = B_PACK_CHARS('_', 'P', 'I', 'D'),
 
         // Corresponds to TF_ONE_WAY -- an asynchronous call.
         FLAG_ONEWAY             = 0x00000001
@@ -129,6 +130,11 @@ public:
      */
     status_t                getExtension(sp<IBinder>* out);
 
+    /**
+     * Dump PID for a binder, for debugging.
+     */
+    status_t                getDebugPid(pid_t* outPid);
+
     // NOLINTNEXTLINE(google-default-arguments)
     virtual status_t        transact(   uint32_t code,
                                         const Parcel& data,