win: add a child ProcessReader test

snapshot/win/process_reader_win_test.cc

 // Copyright 2015 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #include "snapshot/win/process_reader_win.h"
 
+#include <string.h>
 #include <windows.h>
 
 #include "gtest/gtest.h"
+#include "test/win/win_multiprocess.h"
 
 namespace crashpad {
 namespace test {
 namespace {
 
 TEST(ProcessReaderWin, SelfBasic) {
   ProcessReaderWin process_reader;
   ASSERT_TRUE(process_reader.Initialize(GetCurrentProcess()));
 
 #if !defined(ARCH_CPU_64_BITS)
   EXPECT_FALSE(process_reader.Is64Bit());
 #else
   EXPECT_TRUE(process_reader.Is64Bit());
 #endif
 
   EXPECT_EQ(GetCurrentProcessId(), process_reader.ProcessID());
 
   const char kTestMemory[] = "Some test memory";
   char buffer[arraysize(kTestMemory)];
   ASSERT_TRUE(
       process_reader.ReadMemory(reinterpret_cast<uintptr_t>(kTestMemory),
                                 sizeof(kTestMemory),
                                 &buffer));
   EXPECT_STREQ(kTestMemory, buffer);
 }
 
+const char kTestMemory[] = "Read me from another process";
+
+class ProcessReaderChild final : public WinMultiprocess {
+ public:
+  ProcessReaderChild() : WinMultiprocess() {}
+  ~ProcessReaderChild() {}
+
+ private:
+  void WinMultiprocessParent() override {
+    ProcessReaderWin process_reader;
+    ASSERT_TRUE(process_reader.Initialize(ChildProcess()));
+
+#if !defined(ARCH_CPU_64_BITS)
+    EXPECT_FALSE(process_reader.Is64Bit());
+#else
+    EXPECT_TRUE(process_reader.Is64Bit());
+#endif
+
+    WinVMAddress address;
+    CheckedReadFile(ReadPipeHandle(), &address, sizeof(address));
+
+    char buffer[sizeof(kTestMemory)];
+    ASSERT_TRUE(
+        process_reader.ReadMemory(address, sizeof(kTestMemory), &buffer));
+    EXPECT_EQ(0, strcmp(kTestMemory, buffer));
+  }
+
+  void WinMultiprocessChild() override {
+    WinVMAddress address = reinterpret_cast<WinVMAddress>(kTestMemory);
+    CheckedWriteFile(WritePipeHandle(), &address, sizeof(address));
+
+    // Wait for the parent to signal that it's OK to exit by closing its end of
+    // the pipe.
+    CheckedReadFileAtEOF(ReadPipeHandle());
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessReaderChild);
+};
+
+TEST(ProcessReaderWin, ChildBasic) {
+  ProcessReaderChild process_reader_child;
+  process_reader_child.Run();
+}
+
 TEST(ProcessReaderWin, SelfOneThread) {
   ProcessReaderWin process_reader;
   ASSERT_TRUE(process_reader.Initialize(GetCurrentProcess()));
 
   const std::vector<ProcessReaderWin::Thread>& threads =
       process_reader.Threads();
 
   // If other tests ran in this process previously, threads may have been
   // created and may still be running. This check must look for at least one
   // thread, not exactly one thread.
   ASSERT_GE(threads.size(), 1u);
 
   EXPECT_EQ(GetThreadId(GetCurrentThread()), threads[0].id);
 #if defined(ARCH_CPU_64_BITS)
   EXPECT_NE(0, threads[0].context.Rip);
 #else
   EXPECT_NE(0, threads[0].context.Eip);
 #endif
 
   EXPECT_EQ(0, threads[0].suspend_count);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace crashpad