commit 4407bc1e3a473f7c6c7beaef61b5862c67640e58
author Andrei Homescu <ahomescu@google.com> Tue Mar 21 23:25:25 2023 +0000
committer Andrei Homescu <ahomescu@google.com> Tue Mar 21 23:32:16 2023 +0000
tree fd2345dd917f3f57220f827a863b5a3c5a058c96
parent 637a8a4b41c5d68d3768bd65f218818a6a1a3a5f

RPC Binder: Fix TIPC disconnect error code

TIPC on Android returns ENOTCONN if the connection
goes down. Most of libbinder uses DEAD_OBJECT which is
-EPIPE instead. This adds a new function that converts
-ENOTCONN to DEAD_OBJECT manually when returning from
RpcTransportTipcAndroid, for better compatibility with
the rest of libbinder and its tests.

Bug: 230135749
Test: binderRpcToTrustyTest
Change-Id: I6e4b7bdbe214f23f195e14a0e023eba7e944085b

libs/binder/RpcTransportTipcAndroid.cpp

diff --git a/libs/binder/RpcTransportTipcAndroid.cpp b/libs/binder/RpcTransportTipcAndroid.cpp
index 8b3ddfb..d5a6da2 100644
--- a/libs/binder/RpcTransportTipcAndroid.cpp
+++ b/libs/binder/RpcTransportTipcAndroid.cpp
@@ -54,7 +54,7 @@
             }
 
             LOG_RPC_DETAIL("RpcTransport poll(): %s", strerror(savedErrno));
-            return -savedErrno;
+            return adjustStatus(-savedErrno);
         }
 
         if (pfd.revents & POLLNVAL) {
@@ -87,8 +87,10 @@
                                 "File descriptors are not supported on Trusty yet");
             return TEMP_FAILURE_RETRY(tipc_send(mSocket.fd.get(), iovs, niovs, nullptr, 0));
         };
-        return interruptableReadOrWrite(mSocket, fdTrigger, iovs, niovs, writeFn, "tipc_send",
-                                        POLLOUT, altPoll);
+
+        status_t status = interruptableReadOrWrite(mSocket, fdTrigger, iovs, niovs, writeFn,
+                                                   "tipc_send", POLLOUT, altPoll);
+        return adjustStatus(status);
     }
 
     status_t interruptableReadFully(
@@ -121,13 +123,26 @@
 
             return processSize;
         };
-        return interruptableReadOrWrite(mSocket, fdTrigger, iovs, niovs, readFn, "read", POLLIN,
-                                        altPoll);
+
+        status_t status = interruptableReadOrWrite(mSocket, fdTrigger, iovs, niovs, readFn, "read",
+                                                   POLLIN, altPoll);
+        return adjustStatus(status);
     }
 
     bool isWaiting() override { return mSocket.isInPollingState(); }
 
 private:
+    status_t adjustStatus(status_t status) {
+        if (status == -ENOTCONN) {
+            // TIPC returns ENOTCONN on disconnect, but that's basically
+            // the same as DEAD_OBJECT and the latter is the common libbinder
+            // error code for dead connections
+            return DEAD_OBJECT;
+        }
+
+        return status;
+    }
+
     status_t fillReadBuffer() {
         if (mReadBufferPos < mReadBufferSize) {
             return OK;
@@ -167,7 +182,7 @@
                     continue;
                 } else {
                     LOG_RPC_DETAIL("RpcTransport fillBuffer(): %s", strerror(savedErrno));
-                    return -savedErrno;
+                    return adjustStatus(-savedErrno);
                 }
             } else {
                 mReadBufferSize = static_cast<size_t>(processSize);