From 6933d54e0944c773a39ee69ecb34ede3bebf3799 Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Tue, 26 Mar 2019 13:21:42 -0700
Subject: [PATCH] adbd: listen to all functionfs events.

Monitor for FUNCTIONFS_UNBIND as well, so that in the case where we get
FUNCTIONFS_BIND, FUNCTIONFS_UNBIND, FUNCTIONFS_BIND, we don't trigger an
assertion failure from seeing two FUNCTIONFS_BINDs.

Bug: http://b/129134256
Test: manual
Change-Id: I80af5f4b833513e932262638b9f8d76bbcb35504
---
 adb/daemon/usb.cpp | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/adb/daemon/usb.cpp b/adb/daemon/usb.cpp
index 765357971..8a5000336 100644
--- a/adb/daemon/usb.cpp
+++ b/adb/daemon/usb.cpp
@@ -267,7 +267,7 @@ struct UsbFfsConnection : public Connection {
             adb_thread_setname("UsbFfs-monitor");
 
             bool bound = false;
-            bool started = false;
+            bool enabled = false;
             bool running = true;
             while (running) {
                 adb_pollfd pfd[2] = {
@@ -298,16 +298,32 @@ struct UsbFfsConnection : public Connection {
                 switch (event.type) {
                     case FUNCTIONFS_BIND:
                         CHECK(!bound) << "received FUNCTIONFS_BIND while already bound?";
+                        CHECK(!enabled) << "received FUNCTIONFS_BIND while already enabled?";
                         bound = true;
+
                         break;
 
                     case FUNCTIONFS_ENABLE:
-                        CHECK(!started) << "received FUNCTIONFS_ENABLE while already running?";
-                        started = true;
+                        CHECK(bound) << "received FUNCTIONFS_ENABLE while not bound?";
+                        CHECK(!enabled) << "received FUNCTIONFS_ENABLE while already enabled?";
+                        enabled = true;
+
                         StartWorker();
                         break;
 
                     case FUNCTIONFS_DISABLE:
+                        CHECK(bound) << "received FUNCTIONFS_DISABLE while not bound?";
+                        CHECK(enabled) << "received FUNCTIONFS_DISABLE while not enabled?";
+                        enabled = false;
+
+                        running = false;
+                        break;
+
+                    case FUNCTIONFS_UNBIND:
+                        CHECK(!enabled) << "received FUNCTIONFS_UNBIND while still enabled?";
+                        CHECK(bound) << "received FUNCTIONFS_UNBIND when not bound?";
+                        bound = false;
+
                         running = false;
                         break;
                 }
@@ -339,7 +355,7 @@ struct UsbFfsConnection : public Connection {
                     LOG(FATAL) << "hit EOF on eventfd";
                 }
 
-                WaitForEvents();
+                ReadEvents();
             }
         });
     }
@@ -389,7 +405,7 @@ struct UsbFfsConnection : public Connection {
         return block;
     }
 
-    void WaitForEvents() {
+    void ReadEvents() {
         static constexpr size_t kMaxEvents = kUsbReadQueueDepth + kUsbWriteQueueDepth;
         struct io_event events[kMaxEvents];
         struct timespec timeout = {.tv_sec = 0, .tv_nsec = 0};