adb: fix two device offline problems.

When device goes offline, user usually has to manually replug the
usb device. This patch tries to solve two offline situations, all
because when adb on host is killed, the adbd on device is not notified.

1. When adb server is killed while pushing a large file to device,
the device is still reading the unfinished large message. So the
device thinks of the CNXN message as part of the previous unfinished
message, so it doesn't reply and the device is in offline state.

The solution is to add a write_msg_lock in atransport struct. And it
kicks the transport only after sending a whole message. By kicking
all transports before exit, we ensure that we don't write part of
a message to any device. So next time we start adb server, the device
should be waiting for a new message.

2. When adb server is killed while pulling a large file from device,
the device is still trying to send the unfinished large message. So
adb on host usually reads data with EOVERFLOW error. This is because
adb on host is reading less than one packet sent from device.

The solution is to use buffered read on host. The max packet size
of bulk transactions in USB 3.0 is 1024 bytes. By preparing an at least
1024 bytes buffer when reading, EOVERFLOW no longer occurs. And teach
adb host to ignore wrong messages.

To be safe, this patch doesn't change any logic on device.

Bug: http://b/32952319
Test: run python -m unittest -q test_device.DeviceOfflineTest
Test: on linux/mac/windows with bullhead, ryu.
Change-Id: Ib149d30028a62a6f03857b8a95ab5a1d6e9b9c4e

1 files changed, 36 insertions, 27 deletions

diff --git a/adb/adb.cpp b/adb/adb.cpp
index cf6b3593d..33d6bda47 100644
--- a/adb/adb.cpp
+++ b/adb/adb.cpp
@@ -253,6 +253,19 @@ void send_connect(atransport* t) {
     send_packet(cp, t);
 }
 
+#if ADB_HOST
+
+void SendConnectOnHost(atransport* t) {
+    // Send an empty message before A_CNXN message. This is because the data toggle of the ep_out on
+    // host and ep_in on device may not be the same.
+    apacket* p = get_apacket();
+    CHECK(p);
+    send_packet(p, t);
+    send_connect(t);
+}
+
+#endif
+
 // qual_overwrite is used to overwrite a qualifier string.  dst is a
 // pointer to a char pointer.  It is assumed that if *dst is non-NULL, it
 // was malloc'ed and needs to freed.  *dst will be set to a dup of src.
@@ -299,29 +312,29 @@ void parse_banner(const std::string& banner, atransport* t) {
     const std::string& type = pieces[0];
     if (type == "bootloader") {
         D("setting connection_state to kCsBootloader");
-        t->connection_state = kCsBootloader;
+        t->SetConnectionState(kCsBootloader);
         update_transports();
     } else if (type == "device") {
         D("setting connection_state to kCsDevice");
-        t->connection_state = kCsDevice;
+        t->SetConnectionState(kCsDevice);
         update_transports();
     } else if (type == "recovery") {
         D("setting connection_state to kCsRecovery");
-        t->connection_state = kCsRecovery;
+        t->SetConnectionState(kCsRecovery);
         update_transports();
     } else if (type == "sideload") {
         D("setting connection_state to kCsSideload");
-        t->connection_state = kCsSideload;
+        t->SetConnectionState(kCsSideload);
         update_transports();
     } else {
         D("setting connection_state to kCsHost");
-        t->connection_state = kCsHost;
+        t->SetConnectionState(kCsHost);
     }
 }
 
 static void handle_new_connection(atransport* t, apacket* p) {
-    if (t->connection_state != kCsOffline) {
-        t->connection_state = kCsOffline;
+    if (t->GetConnectionState() != kCsOffline) {
+        t->SetConnectionState(kCsOffline);
         handle_offline(t);
     }
 
@@ -355,10 +368,10 @@ void handle_packet(apacket *p, atransport *t)
         if (p->msg.arg0){
             send_packet(p, t);
 #if ADB_HOST
-            send_connect(t);
+            SendConnectOnHost(t);
 #endif
         } else {
-            t->connection_state = kCsOffline;
+            t->SetConnectionState(kCsOffline);
             handle_offline(t);
             send_packet(p, t);
         }
@@ -372,7 +385,9 @@ void handle_packet(apacket *p, atransport *t)
         switch (p->msg.arg0) {
 #if ADB_HOST
             case ADB_AUTH_TOKEN:
-                t->connection_state = kCsUnauthorized;
+                if (t->GetConnectionState() == kCsOffline) {
+                    t->SetConnectionState(kCsUnauthorized);
+                }
                 send_auth_response(p->data, p->msg.data_length, t);
                 break;
 #else
@@ -391,7 +406,7 @@ void handle_packet(apacket *p, atransport *t)
                 break;
 #endif
             default:
-                t->connection_state = kCsOffline;
+                t->SetConnectionState(kCsOffline);
                 handle_offline(t);
                 break;
         }
@@ -1034,7 +1049,6 @@ static int SendOkay(int fd, const std::string& s) {
     SendProtocolString(fd, s);
     return 0;
 }
-#endif
 
 int handle_host_request(const char* service, TransportType type,
                         const char* serial, int reply_fd, asocket* s) {
@@ -1053,7 +1067,6 @@ int handle_host_request(const char* service, TransportType type,
         android::base::quick_exit(0);
     }
 
-#if ADB_HOST
     // "transport:" is used for switching transport with a specified serial number
     // "transport-usb:" is used for switching transport to the only USB transport
     // "transport-local:" is used for switching transport to the only local transport
@@ -1098,16 +1111,10 @@ int handle_host_request(const char* service, TransportType type,
     if (!strcmp(service, "reconnect-offline")) {
         std::string response;
         close_usb_devices([&response](const atransport* transport) {
-            switch (transport->connection_state) {
+            switch (transport->GetConnectionState()) {
                 case kCsOffline:
                 case kCsUnauthorized:
-                    response += "reconnecting ";
-                    if (transport->serial) {
-                        response += transport->serial;
-                    } else {
-                        response += "<unknown>";
-                    }
-                    response += "\n";
+                    response += "reconnecting " + transport->serial_name() + "\n";
                     return true;
                 default:
                     return false;
@@ -1131,7 +1138,6 @@ int handle_host_request(const char* service, TransportType type,
         return 0;
     }
 
-#if ADB_HOST
     if (!strcmp(service, "host-features")) {
         FeatureSet features = supported_features();
         // Abuse features to report libusb status.
@@ -1141,7 +1147,6 @@ int handle_host_request(const char* service, TransportType type,
         SendOkay(reply_fd, FeatureSetToString(features));
         return 0;
     }
-#endif
 
     // remove TCP transport
     if (!strncmp(service, "disconnect:", 11)) {
@@ -1211,15 +1216,19 @@ int handle_host_request(const char* service, TransportType type,
     }
 
     if (!strcmp(service, "reconnect")) {
-        if (s->transport != nullptr) {
-            kick_transport(s->transport);
+        std::string response;
+        atransport* t = acquire_one_transport(type, serial, nullptr, &response, true);
+        if (t != nullptr) {
+            kick_transport(t);
+            response =
+                "reconnecting " + t->serial_name() + " [" + t->connection_state_name() + "]\n";
         }
-        return SendOkay(reply_fd, "done");
+        return SendOkay(reply_fd, response);
     }
-#endif // ADB_HOST
 
     int ret = handle_forward_request(service, type, serial, reply_fd);
     if (ret >= 0)
       return ret - 1;
     return -1;
 }
+#endif  // ADB_HOST