binder: add getDriverName()

Ass ProcessState::getDriverName() to retrieve the /dev node that
libbinder is initialized with in this process.  This can be used
elsewhere to add debug code that is enabled for only one binder domain
or another.

Test: sailfish

Change-Id: I3ea9f0dcc97204508791bdeb70f790980be278a5
Signed-off-by: Iliyan Malchev <malchev@google.com>

2 files changed, 10 insertions, 1 deletions

diff --git a/include/binder/ProcessState.h b/include/binder/ProcessState.h
index 05e9d09ee8..1ef045d455 100644
--- a/include/binder/ProcessState.h
+++ b/include/binder/ProcessState.h
@@ -69,6 +69,8 @@ public:
             status_t            setThreadPoolMaxThreadCount(size_t maxThreads);
             void                giveThreadPoolName();
 
+            String8             getDriverName();
+
 private:
     friend class IPCThreadState;
     
@@ -86,6 +88,7 @@ private:
 
             handle_entry*       lookupHandleLocked(int32_t handle);
 
+            String8             mDriverName;
             int                 mDriverFD;
             void*               mVMStart;
 
diff --git a/libs/binder/ProcessState.cpp b/libs/binder/ProcessState.cpp
index 5c4cfe2156..9ccf07ca2a 100644
--- a/libs/binder/ProcessState.cpp
+++ b/libs/binder/ProcessState.cpp
@@ -317,6 +317,10 @@ void ProcessState::giveThreadPoolName() {
     androidSetThreadName( makeBinderThreadName().string() );
 }
 
+String8 ProcessState::getDriverName() {
+    return mDriverName;
+}
+
 static int open_driver(const char *driver)
 {
     int fd = open(driver, O_RDWR | O_CLOEXEC);
@@ -346,7 +350,8 @@ static int open_driver(const char *driver)
 }
 
 ProcessState::ProcessState(const char *driver)
-    : mDriverFD(open_driver(driver))
+    : mDriverName(String8(driver))
+    , mDriverFD(open_driver(driver))
     , mVMStart(MAP_FAILED)
     , mThreadCountLock(PTHREAD_MUTEX_INITIALIZER)
     , mThreadCountDecrement(PTHREAD_COND_INITIALIZER)
@@ -367,6 +372,7 @@ ProcessState::ProcessState(const char *driver)
             ALOGE("Using /dev/binder failed: unable to mmap transaction memory.\n");
             close(mDriverFD);
             mDriverFD = -1;
+            mDriverName.clear();
         }
     }