Fetch peer credentials for local sockets

Fetch the PID, UID, and GID of the remote side of a local socket
connection in case any users of this library class want to check it.

Change-Id: Ia3230e6bc68ab6f93160df9f5996d2bf744b872c
diff --git a/include/sysutils/SocketClient.h b/include/sysutils/SocketClient.h
index 469dd9d..e7fb177 100644
--- a/include/sysutils/SocketClient.h
+++ b/include/sysutils/SocketClient.h
@@ -4,16 +4,29 @@
 #include "../../../frameworks/base/include/utils/List.h"
 
 #include <pthread.h>
+#include <sys/types.h>
 
 class SocketClient {
     int             mSocket;
     pthread_mutex_t mWriteMutex;
 
+    /* Peer process ID */
+    pid_t mPid;
+
+    /* Peer user ID */
+    uid_t mUid;
+
+    /* Peer group ID */
+    gid_t mGid;
+
 public:
     SocketClient(int sock);
     virtual ~SocketClient() {}
 
     int getSocket() { return mSocket; }
+    pid_t getPid() const { return mPid; }
+    uid_t getUid() const { return mUid; }
+    gid_t getGid() const { return mGid; }
 
     int sendMsg(int code, const char *msg, bool addErrno);
     int sendMsg(const char *msg);