From f74c1a955617b9b571f9439b43cc618d5aba354b Mon Sep 17 00:00:00 2001
From: David Anderson <dvander@google.com>
Date: Mon, 12 Oct 2020 15:54:49 -0700
Subject: [PATCH] fastbootd: Add more logging for when the USB transport fails.

Bug: 161542676
Test: fastboot flashall
Change-Id: Ief4e7452b72504c51c807dd38a07765ad65c96a4
---
 fastboot/device/fastboot_device.cpp | 8 +++++++-
 fastboot/device/usb_client.cpp      | 8 +++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/fastboot/device/fastboot_device.cpp b/fastboot/device/fastboot_device.cpp
index 52ea9f006..35f3de020 100644
--- a/fastboot/device/fastboot_device.cpp
+++ b/fastboot/device/fastboot_device.cpp
@@ -139,7 +139,13 @@ bool FastbootDevice::WriteStatus(FastbootResult result, const std::string& messa
 bool FastbootDevice::HandleData(bool read, std::vector<char>* data) {
     auto read_write_data_size = read ? this->get_transport()->Read(data->data(), data->size())
                                      : this->get_transport()->Write(data->data(), data->size());
-    if (read_write_data_size == -1 || static_cast<size_t>(read_write_data_size) != data->size()) {
+    if (read_write_data_size == -1) {
+        LOG(ERROR) << (read ? "read from" : "write to") << " transport failed";
+        return false;
+    }
+    if (static_cast<size_t>(read_write_data_size) != data->size()) {
+        LOG(ERROR) << (read ? "read" : "write") << " expected " << data->size() << " bytes, got "
+                   << read_write_data_size;
         return false;
     }
     return true;
diff --git a/fastboot/device/usb_client.cpp b/fastboot/device/usb_client.cpp
index c65316707..2caced476 100644
--- a/fastboot/device/usb_client.cpp
+++ b/fastboot/device/usb_client.cpp
@@ -248,7 +248,12 @@ ClientUsbTransport::ClientUsbTransport()
 }
 
 ssize_t ClientUsbTransport::Read(void* data, size_t len) {
-    if (handle_ == nullptr || len > SSIZE_MAX) {
+    if (handle_ == nullptr) {
+        LOG(ERROR) << "ClientUsbTransport: no handle";
+        return -1;
+    }
+    if (len > SSIZE_MAX) {
+        LOG(ERROR) << "ClientUsbTransport: maximum length exceeds bounds";
         return -1;
     }
     char* char_data = static_cast<char*>(data);
@@ -258,6 +263,7 @@ ssize_t ClientUsbTransport::Read(void* data, size_t len) {
         auto bytes_read_now =
                 handle_->read(handle_.get(), char_data, bytes_to_read, true /* allow_partial */);
         if (bytes_read_now < 0) {
+            PLOG(ERROR) << "ClientUsbTransport: read failed";
             return bytes_read_total == 0 ? -1 : bytes_read_total;
         }
         bytes_read_total += bytes_read_now;