From 08018dd92565e74c46e58aae91895edad761cc84 Mon Sep 17 00:00:00 2001
From: Kenny Root <kroot@google.com>
Date: Sat, 1 Feb 2020 11:29:20 -0800
Subject: [PATCH] rebootescrow: eliminate copy during read

Instead of reading into a std::string, read directly into the std::vector of bytes
This saves a copy and reduces memory overhead slightly.

Test: atest VtsHalRebootEscrowTargetTest
Bug: 148177693
Change-Id: I4dfe552f21394fb0891858b34a481b489dc3c684
---
 rebootescrow/aidl/default/RebootEscrow.cpp | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/rebootescrow/aidl/default/RebootEscrow.cpp b/rebootescrow/aidl/default/RebootEscrow.cpp
index 5ae96f6086..dbc09215b3 100644
--- a/rebootescrow/aidl/default/RebootEscrow.cpp
+++ b/rebootescrow/aidl/default/RebootEscrow.cpp
@@ -55,13 +55,12 @@ ndk::ScopedAStatus RebootEscrow::retrieveKey(std::vector<int8_t>* _aidl_return)
         return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_UNSUPPORTED_OPERATION));
     }
 
-    std::string encodedString;
-    if (!::android::base::ReadFdToString(fd, &encodedString)) {
-        LOG(WARNING) << "Could not read device to string";
+    std::vector<uint8_t> encodedBytes(hadamard::OUTPUT_SIZE_BYTES);
+    if (!::android::base::ReadFully(fd, &encodedBytes[0], encodedBytes.size())) {
+        LOG(WARNING) << "Could not read device";
         return ndk::ScopedAStatus(AStatus_fromExceptionCode(EX_UNSUPPORTED_OPERATION));
     }
 
-    std::vector<uint8_t> encodedBytes(encodedString.begin(), encodedString.end());
     auto keyBytes = hadamard::DecodeKey(encodedBytes);
 
     std::vector<int8_t> signedKeyBytes(keyBytes.begin(), keyBytes.end());