commit 4520246d3534c087f3e9253c34f99dd1e45b7bd7
author Xianzhu Wang <wangxianzhu@google.com> Thu Sep 29 12:59:55 2011 +0800
committer Xianzhu Wang <wangxianzhu@google.com> Thu Sep 29 13:42:32 2011 +0800
tree 68fb2d909e6258f785347d60a026b42efeaa93b4
parent 2a32df25b8bb307693173911041458aaca84c84c

Fix SocketListener socket leak issue.

The problem was: if a socket is shared between SocketListener and another
thread, only if the last reference is removed by SocketListener can the socket
be closed, otherwise the socket will leak. This sometimes happens in netd's
dnsproxyd.

This change let the SocketClient own the socket and close the socket when
the SocketClient is destructed.

Change-Id: I2865fbfe9ee4d8b3e43d7e02919dbb2d261f70de

include/sysutils/SocketClient.h

diff --git a/include/sysutils/SocketClient.h b/include/sysutils/SocketClient.h
index d6bb7d5..7d2b1d6 100644
--- a/include/sysutils/SocketClient.h
+++ b/include/sysutils/SocketClient.h
@@ -8,6 +8,7 @@
 
 class SocketClient {
     int             mSocket;
+    bool            mSocketOwned;
     pthread_mutex_t mWriteMutex;
 
     /* Peer process ID */
@@ -24,8 +25,8 @@
     int mRefCount;
 
 public:
-    SocketClient(int sock);
-    virtual ~SocketClient() {}
+    SocketClient(int sock, bool owned);
+    virtual ~SocketClient();
 
     int getSocket() { return mSocket; }
     pid_t getPid() const { return mPid; }

libsysutils/src/SocketClient.cpp

diff --git a/libsysutils/src/SocketClient.cpp b/libsysutils/src/SocketClient.cpp
index 90ca52e..722dcb2 100644
--- a/libsysutils/src/SocketClient.cpp
+++ b/libsysutils/src/SocketClient.cpp
@@ -10,8 +10,9 @@
 
 #include <sysutils/SocketClient.h>
 
-SocketClient::SocketClient(int socket)
+SocketClient::SocketClient(int socket, bool owned)
         : mSocket(socket)
+        , mSocketOwned(owned)
         , mPid(-1)
         , mUid(-1)
         , mGid(-1)
@@ -32,6 +33,13 @@
     }
 }
 
+SocketClient::~SocketClient()
+{
+    if (mSocketOwned) {
+        close(mSocket);
+    }
+}
+
 int SocketClient::sendMsg(int code, const char *msg, bool addErrno) {
     char *buf;
     const char* arg;

libsysutils/src/SocketListener.cpp

diff --git a/libsysutils/src/SocketListener.cpp b/libsysutils/src/SocketListener.cpp
index fcad624..3f871ea 100644
--- a/libsysutils/src/SocketListener.cpp
+++ b/libsysutils/src/SocketListener.cpp
@@ -79,7 +79,7 @@
         SLOGE("Unable to listen on socket (%s)", strerror(errno));
         return -1;
     } else if (!mListen)
-        mClients->push_back(new SocketClient(mSock));
+        mClients->push_back(new SocketClient(mSock, false));
 
     if (pipe(mCtrlPipe)) {
         SLOGE("pipe failed (%s)", strerror(errno));
@@ -191,7 +191,7 @@
                 continue;
             }
             pthread_mutex_lock(&mClientsLock);
-            mClients->push_back(new SocketClient(c));
+            mClients->push_back(new SocketClient(c, true));
             pthread_mutex_unlock(&mClientsLock);
         }
 
@@ -225,12 +225,8 @@
                     }
                 }
                 pthread_mutex_unlock(&mClientsLock);
-                /* Destroy the client */
-                int socket = c->getSocket();
-                if (c->decRef()) {
-                    // Note: 'c' is deleted memory at this point.
-                    close(socket);
-                }
+                /* Remove our reference to the client */
+                c->decRef();
             }
         }
     }