SocketClient: add optional reference counting
Needed to fix a race in netd.
Bug: 3438459
Change-Id: Icd7f5f035510235f733a25c0621479d3e644b152
diff --git a/include/sysutils/SocketClient.h b/include/sysutils/SocketClient.h
index 2fcc331..ef6dd9b 100644
--- a/include/sysutils/SocketClient.h
+++ b/include/sysutils/SocketClient.h
@@ -19,6 +19,10 @@
/* Peer group ID */
gid_t mGid;
+ /* Reference count (starts at 1) */
+ pthread_mutex_t mRefCountMutex;
+ int mRefCount;
+
public:
SocketClient(int sock);
virtual ~SocketClient() {}
@@ -34,6 +38,13 @@
// Sending binary data:
int sendData(const void *data, int len);
+
+ // Optional reference counting. Reference count starts at 1. If
+ // it's decremented to 0, it deletes itself.
+ // SocketListener creates a SocketClient (at refcount 1) and calls
+ // decRef() when it's done with the client.
+ void incRef();
+ void decRef();
};
typedef android::List<SocketClient *> SocketClientCollection;
diff --git a/libsysutils/src/SocketClient.cpp b/libsysutils/src/SocketClient.cpp
index a6aed26..6d4dff4 100644
--- a/libsysutils/src/SocketClient.cpp
+++ b/libsysutils/src/SocketClient.cpp
@@ -15,8 +15,10 @@
, mPid(-1)
, mUid(-1)
, mGid(-1)
+ , mRefCount(1)
{
pthread_mutex_init(&mWriteMutex, NULL);
+ pthread_mutex_init(&mRefCountMutex, NULL);
struct ucred creds;
socklen_t szCreds = sizeof(creds);
@@ -100,3 +102,22 @@
pthread_mutex_unlock(&mWriteMutex);
return 0;
}
+
+void SocketClient::incRef() {
+ pthread_mutex_lock(&mRefCountMutex);
+ mRefCount++;
+ pthread_mutex_unlock(&mRefCountMutex);
+}
+
+void SocketClient::decRef() {
+ bool deleteSelf = false;
+ pthread_mutex_lock(&mRefCountMutex);
+ mRefCount--;
+ if (mRefCount == 0) {
+ deleteSelf = true;
+ }
+ pthread_mutex_unlock(&mRefCountMutex);
+ if (deleteSelf) {
+ delete this;
+ }
+}
diff --git a/libsysutils/src/SocketListener.cpp b/libsysutils/src/SocketListener.cpp
index 611d5fe..dde9b55 100644
--- a/libsysutils/src/SocketListener.cpp
+++ b/libsysutils/src/SocketListener.cpp
@@ -55,7 +55,7 @@
}
SocketClientCollection::iterator it;
for (it = mClients->begin(); it != mClients->end();) {
- delete (*it);
+ (*it)->decRef();
it = mClients->erase(it);
}
delete mClients;
@@ -226,7 +226,7 @@
pthread_mutex_unlock(&mClientsLock);
/* Destroy the client */
close(c->getSocket());
- delete c;
+ c->decRef();
}
}
}