From ef57d54f80774701eee8bdb45185fb33e5ced473 Mon Sep 17 00:00:00 2001
From: Ting-Yuan Huang <laszio@google.com>
Date: Wed, 19 Oct 2016 18:15:30 -0700
Subject: [PATCH] adb: fix undefined behavior

system/core/adb/shell_service_protocol_test.cpp:94:14: warning: Null
passed to a callee that requires a non-null 1st parameter
            !memcmp(data, protocol->data(), data_length));

C99 requires memcmp() to take non-null pointers.

Bug: none
Test: clang-tidy doesn't complain
Change-Id: I77b8d9373fa257a070ffc7fd318231c2c9ea84c3
---
 adb/shell_service_protocol_test.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/adb/shell_service_protocol_test.cpp b/adb/shell_service_protocol_test.cpp
index a826035ab..b0fa3edbb 100644
--- a/adb/shell_service_protocol_test.cpp
+++ b/adb/shell_service_protocol_test.cpp
@@ -86,9 +86,10 @@ sig_t ShellProtocolTest::saved_sigpipe_handler_ = nullptr;
 
 namespace {
 
-// Returns true if the packet contains the given values.
+// Returns true if the packet contains the given values. `data` can't be null.
 bool PacketEquals(const ShellProtocol* protocol, ShellProtocol::Id id,
                     const void* data, size_t data_length) {
+    // Note that passing memcmp null is bad, even if data_length is 0.
     return (protocol->id() == id &&
             protocol->data_length() == data_length &&
             !memcmp(data, protocol->data(), data_length));
@@ -130,7 +131,8 @@ TEST_F(ShellProtocolTest, ZeroLengthPacket) {
 
     ASSERT_TRUE(write_protocol_->Write(id, 0));
     ASSERT_TRUE(read_protocol_->Read());
-    ASSERT_TRUE(PacketEquals(read_protocol_, id, nullptr, 0));
+    char buf[1];
+    ASSERT_TRUE(PacketEquals(read_protocol_, id, buf, 0));
 }
 
 // Tests exit code packets.