Add most of ProcessReader and its test

util/mac/process_reader_test.cc

+// Copyright 2014 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 "util/mac/process_reader.h"
+
+#include <dispatch/dispatch.h>
+#include <mach/mach.h>
+#include <string.h>
+
+#include <map>
+#include <string>
+
+#include "base/logging.h"
+#include "base/mac/scoped_mach_port.h"
+#include "base/posix/eintr_wrapper.h"
+#include "build/build_config.h"
+#include "gtest/gtest.h"
+#include "util/file/fd_io.h"
+#include "util/stdlib/pointer_container.h"
+#include "util/test/mac/mach_errors.h"
+#include "util/test/mac/mach_multiprocess.h"
+#include "util/test/errors.h"
+
+namespace {
+
+using namespace crashpad;
+using namespace crashpad::test;
+
+TEST(ProcessReader, SelfBasic) {
+  ProcessReader process_reader;
+  ASSERT_TRUE(process_reader.Initialize(mach_task_self()));
+
+#if !defined(ARCH_CPU_64_BITS)
+  EXPECT_FALSE(process_reader.Is64Bit());
+#else
+  EXPECT_TRUE(process_reader.Is64Bit());
+#endif
+
+  EXPECT_EQ(getpid(), process_reader.ProcessID());
+  EXPECT_EQ(getppid(), process_reader.ParentProcessID());
+
+  const char kTestMemory[] = "Some test memory";
+  char buffer[arraysize(kTestMemory)];
+  ASSERT_TRUE(process_reader.Memory()->Read(
+      reinterpret_cast<mach_vm_address_t>(kTestMemory),
+      sizeof(kTestMemory),
+      &buffer));
+  EXPECT_STREQ(kTestMemory, buffer);
+}
+
+const char kTestMemory[] = "Read me from another process";
+
+class ProcessReaderChild final : public MachMultiprocess {
+ public:
+  ProcessReaderChild() : MachMultiprocess() {}
+
+  ~ProcessReaderChild() {}
+
+ protected:
+  void Parent() override {
+    ProcessReader process_reader;
+    ASSERT_TRUE(process_reader.Initialize(ChildTask()));
+
+#if !defined(ARCH_CPU_64_BITS)
+    EXPECT_FALSE(process_reader.Is64Bit());
+#else
+    EXPECT_TRUE(process_reader.Is64Bit());
+#endif
+
+    EXPECT_EQ(getpid(), process_reader.ParentProcessID());
+    EXPECT_EQ(ChildPID(), process_reader.ProcessID());
+
+    int read_fd = ReadPipeFD();
+
+    mach_vm_address_t address;
+    int rv = ReadFD(read_fd, &address, sizeof(address));
+    ASSERT_EQ(static_cast<ssize_t>(sizeof(address)), rv)
+        << ErrnoMessage("read");
+
+    std::string read_string;
+    ASSERT_TRUE(process_reader.Memory()->ReadCString(address, &read_string));
+    EXPECT_EQ(kTestMemory, read_string);
+
+    // Tell the child that it’s OK to exit. The child needed to be kept alive
+    // until the parent finished working with it.
+    int write_fd = WritePipeFD();
+    char c = '\0';
+    rv = WriteFD(write_fd, &c, 1);
+    ASSERT_EQ(1, rv) << ErrnoMessage("write");
+  }
+
+  void Child() override {
+    int write_fd = WritePipeFD();
+
+    mach_vm_address_t address =
+        reinterpret_cast<mach_vm_address_t>(kTestMemory);
+    int rv = WriteFD(write_fd, &address, sizeof(address));
+    ASSERT_EQ(static_cast<ssize_t>(sizeof(address)), rv)
+        << ErrnoMessage("write");
+
+    // Wait for the parent to say that it’s OK to exit.
+    int read_fd = ReadPipeFD();
+    char c;
+    rv = ReadFD(read_fd, &c, 1);
+    ASSERT_EQ(1, rv) << ErrnoMessage("read");
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ProcessReaderChild);
+};
+
+TEST(ProcessReader, ChildBasic) {
+  ProcessReaderChild process_reader_child;
+  process_reader_child.Run();
+}
+
+// Returns a thread ID given a pthread_t. This wraps pthread_threadid_np() but
+// that function has a cumbersome interface because it returns a success value.
+// This function CHECKs success and returns the thread ID directly.
+uint64_t PthreadToThreadID(pthread_t pthread) {
+  uint64_t thread_id;
+  int rv = pthread_threadid_np(pthread, &thread_id);
+  CHECK_EQ(rv, 0);
+  return thread_id;
+}
+
+TEST(ProcessReader, SelfOneThread) {
+  ProcessReader process_reader;
+  ASSERT_TRUE(process_reader.Initialize(mach_task_self()));
+
+  const std::vector<ProcessReaderThread>& 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(PthreadToThreadID(pthread_self()), threads[0].id);
+
+  base::mac::ScopedMachSendRight thread_self(mach_thread_self());
+  EXPECT_EQ(thread_self, threads[0].port);
+
+  EXPECT_EQ(0, threads[0].suspend_count);
+}
+
+class TestThreadPool {
+ public:
+  struct ThreadExpectation {
+    mach_vm_address_t stack_address;
+    int suspend_count;
+  };
+
+  TestThreadPool() : thread_infos_() {
+  }
+
+  // Resumes suspended threads, signals each thread’s exit semaphore asking it
+  // to exit, and joins each thread, blocking until they have all exited.
+  ~TestThreadPool() {
+    for (ThreadInfo* thread_info : thread_infos_) {
+      mach_port_t thread_port = pthread_mach_thread_np(thread_info->pthread);
+      while (thread_info->suspend_count > 0) {
+        kern_return_t kr = thread_resume(thread_port);
+        EXPECT_EQ(KERN_SUCCESS, kr) << MachErrorMessage(kr, "thread_resume");
+        --thread_info->suspend_count;
+      }
+    }
+
+    for (const ThreadInfo* thread_info : thread_infos_) {
+      dispatch_semaphore_signal(thread_info->exit_semaphore);
+    }
+
+    for (const ThreadInfo* thread_info : thread_infos_) {
+      int rv = pthread_join(thread_info->pthread, NULL);
+      CHECK_EQ(0, rv);
+    }
+  }
+
+  // Starts |thread_count| threads and waits on each thread’s ready semaphore,
+  // so that when this function returns, all threads have been started and have
+  // all run to the point that they’ve signalled that they are ready.
+  void StartThreads(size_t thread_count) {
+    ASSERT_TRUE(thread_infos_.empty());
+
+    for (size_t thread_index = 0; thread_index < thread_count; ++thread_index) {
+      ThreadInfo* thread_info = new ThreadInfo();
+      thread_infos_.push_back(thread_info);
+
+      int rv = pthread_create(&thread_info->pthread,
+                              NULL,
+                              ThreadMain,
+                              thread_info);
+      ASSERT_EQ(0, rv);
+    }
+
+    for (const ThreadInfo* thread_info : thread_infos_) {
+      long rv = dispatch_semaphore_wait(thread_info->ready_semaphore,
+                                        DISPATCH_TIME_FOREVER);
+      ASSERT_EQ(0, rv);
+    }
+
+    // If present, suspend the thread at indices 1 through 3 the same number of
+    // times as their index. This tests reporting of suspend counts.
+    for (size_t thread_index = 1;
+         thread_index < thread_infos_.size() && thread_index < 4;
+         ++thread_index) {
+      mach_port_t thread_port =
+          pthread_mach_thread_np(thread_infos_[thread_index]->pthread);
+      for (size_t suspend_count = 0;
+           suspend_count < thread_index;
+           ++suspend_count) {
+        kern_return_t kr = thread_suspend(thread_port);
+        EXPECT_EQ(KERN_SUCCESS, kr) << MachErrorMessage(kr, "thread_suspend");
+        if (kr == KERN_SUCCESS) {
+          ++thread_infos_[thread_index]->suspend_count;
+        }
+      }
+    }
+  }
+
+  uint64_t GetThreadInfo(size_t thread_index,
+                         ThreadExpectation* expectation) {
+    CHECK_LT(thread_index, thread_infos_.size());
+
+    const ThreadInfo* thread_info = thread_infos_[thread_index];
+    expectation->stack_address = thread_info->stack_address;
+    expectation->suspend_count = thread_info->suspend_count;
+
+    return PthreadToThreadID(thread_info->pthread);
+  }
+
+ private:
+  struct ThreadInfo {
+    ThreadInfo()
+        : pthread(NULL),
+          stack_address(0),
+          ready_semaphore(dispatch_semaphore_create(0)),
+          exit_semaphore(dispatch_semaphore_create(0)),
+          suspend_count(0) {
+    }
+
+    ~ThreadInfo() {
+      dispatch_release(exit_semaphore);
+      dispatch_release(ready_semaphore);
+    }
+
+    // The thread’s ID, set at the time the thread is created.
+    pthread_t pthread;
+
+    // An address somewhere within the thread’s stack. The thread sets this in
+    // its ThreadMain().
+    mach_vm_address_t stack_address;
+
+    // The worker thread signals ready_semaphore to indicate that it’s done
+    // setting up its ThreadInfo structure. The main thread waits on this
+    // semaphore before using any data that the worker thread is responsible for
+    // setting.
+    dispatch_semaphore_t ready_semaphore;
+
+    // The worker thread waits on exit_semaphore to determine when it’s safe to
+    // exit. The main thread signals exit_semaphore when it no longer needs the
+    // worker thread.
+    dispatch_semaphore_t exit_semaphore;
+
+    // The thread’s suspend count.
+    int suspend_count;
+  };
+
+  static void* ThreadMain(void* argument) {
+    ThreadInfo* thread_info = static_cast<ThreadInfo*>(argument);
+
+    thread_info->stack_address =
+        reinterpret_cast<mach_vm_address_t>(&thread_info);
+
+    dispatch_semaphore_signal(thread_info->ready_semaphore);
+    dispatch_semaphore_wait(thread_info->exit_semaphore, DISPATCH_TIME_FOREVER);
+
+    // Check this here after everything’s known to be synchronized, otherwise
+    // there’s a race between the parent thread storing this thread’s pthread_t
+    // in thread_info_pthread and this thread starting and attempting to access
+    // it.
+    CHECK_EQ(pthread_self(), thread_info->pthread);
+
+    return NULL;
+  }
+
+  // This is a PointerVector because the address of a ThreadInfo object is
+  // passed to each thread’s ThreadMain(), so they cannot move around in memory.
+  PointerVector<ThreadInfo> thread_infos_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestThreadPool);
+};
+
+typedef std::map<uint64_t, TestThreadPool::ThreadExpectation> ThreadMap;
+
+// Verifies that all of the threads in |threads|, obtained from ProcessReader,
+// agree with the expectation in |thread_map|. If |tolerate_extra_threads| is
+// true, |threads| is allowed to contain threads that are not listed in
+// |thread_map|. This is useful when testing situations where code outside of
+// the test’s control (such as system libraries) may start threads, or may have
+// started threads prior to a test’s execution.
+void ExpectSeveralThreads(ThreadMap* thread_map,
+                          const std::vector<ProcessReaderThread>& threads,
+                          const bool tolerate_extra_threads) {
+  if (tolerate_extra_threads) {
+    ASSERT_GE(threads.size(), thread_map->size());
+  } else {
+    ASSERT_EQ(thread_map->size(), threads.size());
+  }
+
+  for (size_t thread_index = 0; thread_index < threads.size(); ++thread_index) {
+    const ProcessReaderThread& thread = threads[thread_index];
+    mach_vm_address_t thread_stack_region_end =
+        thread.stack_region_address + thread.stack_region_size;
+
+    const auto& iterator = thread_map->find(thread.id);
+    if (!tolerate_extra_threads) {
+      // Make sure that the thread is in the expectation map.
+      ASSERT_NE(thread_map->end(), iterator);
+    }
+
+    if (iterator != thread_map->end()) {
+      EXPECT_GE(iterator->second.stack_address, thread.stack_region_address);
+      EXPECT_LT(iterator->second.stack_address, thread_stack_region_end);
+
+      EXPECT_EQ(iterator->second.suspend_count, thread.suspend_count);
+
+      // Remove the thread from the expectation map since it’s already been
+      // found. This makes it easy to check for duplicate thread IDs, and makes
+      // it easy to check that all expected threads were found.
+      thread_map->erase(iterator);
+    }
+
+    // Make sure that this thread’s ID, stack region, and port don’t conflict
+    // with any other thread’s. Each thread should have a unique value for its
+    // ID and port, and each should have its own stack that doesn’t touch any
+    // other thread’s stack.
+    for (size_t other_thread_index = 0;
+         other_thread_index < threads.size();
+         ++other_thread_index) {
+      if (thread_index == other_thread_index) {
+        continue;
+      }
+
+      const ProcessReaderThread& other_thread = threads[other_thread_index];
+
+      EXPECT_NE(thread.id, other_thread.id);
+      EXPECT_NE(thread.port, other_thread.port);
+
+      mach_vm_address_t other_thread_stack_region_end =
+          other_thread.stack_region_address + other_thread.stack_region_size;
+      EXPECT_FALSE(
+          thread.stack_region_address >= other_thread.stack_region_address &&
+          thread.stack_region_address < other_thread_stack_region_end);
+      EXPECT_FALSE(
+          thread_stack_region_end > other_thread.stack_region_address &
+          thread_stack_region_end <= other_thread_stack_region_end);
+    }
+  }
+
+  // Make sure that each expected thread was found.
+  EXPECT_TRUE(thread_map->empty());
+}
+
+TEST(ProcessReader, SelfSeveralThreads) {
+  // Set up the ProcessReader here, before any other threads are running. This
+  // tests that the threads it returns are lazily initialized as a snapshot of
+  // the threads at the time of the first call to Threads(), and not at the
+  // time the ProcessReader was created or initialized.
+  ProcessReader process_reader;
+  ASSERT_TRUE(process_reader.Initialize(mach_task_self()));
+
+  TestThreadPool thread_pool;
+  const size_t kChildThreads = 16;
+  thread_pool.StartThreads(kChildThreads);
+  if (Test::HasFatalFailure()) {
+    return;
+  }
+
+  // Build a map of all expected threads, keyed by each thread’s ID. The values
+  // are addresses that should lie somewhere within each thread’s stack.
+  ThreadMap thread_map;
+  const uint64_t self_thread_id = PthreadToThreadID(pthread_self());
+  TestThreadPool::ThreadExpectation expectation;
+  expectation.stack_address = reinterpret_cast<mach_vm_address_t>(&thread_map);
+  expectation.suspend_count = 0;
+  thread_map[self_thread_id] = expectation;
+  for (size_t thread_index = 0; thread_index < kChildThreads; ++thread_index) {
+    uint64_t thread_id = thread_pool.GetThreadInfo(thread_index, &expectation);
+
+    // There can’t be any duplicate thread IDs.
+    EXPECT_EQ(0u, thread_map.count(thread_id));
+
+    thread_map[thread_id] = expectation;
+  }
+
+  const std::vector<ProcessReaderThread>& threads = process_reader.Threads();
+
+  // Other tests that have run previously may have resulted in the creation of
+  // threads that still exist, so pass true for |tolerate_extra_threads|.
+  ExpectSeveralThreads(&thread_map, threads, true);
+
+  // When testing in-process, verify that when this thread shows up in the
+  // vector, it has the expected thread port, and that this thread port only
+  // shows up once.
+  base::mac::ScopedMachSendRight thread_self(mach_thread_self());
+  bool found_thread_self = false;
+  for (const ProcessReaderThread& thread : threads) {
+    if (thread.port == thread_self) {
+      EXPECT_FALSE(found_thread_self);
+      found_thread_self = true;
+      EXPECT_EQ(self_thread_id, thread.id);
+    }
+  }
+  EXPECT_TRUE(found_thread_self);
+}
+
+class ProcessReaderThreadedChild final : public MachMultiprocess {
+ public:
+  explicit ProcessReaderThreadedChild(size_t thread_count)
+      : MachMultiprocess(),
+        thread_count_(thread_count) {
+  }
+
+  ~ProcessReaderThreadedChild() {}
+
+ protected:
+  void Parent() override {
+    ProcessReader process_reader;
+    ASSERT_TRUE(process_reader.Initialize(ChildTask()));
+
+    int read_fd = ReadPipeFD();
+
+    // Build a map of all expected threads, keyed by each thread’s ID, and with
+    // addresses that should lie somewhere within each thread’s stack as values.
+    // These IDs and addresses all come from the child process via the pipe.
+    ThreadMap thread_map;
+    for (size_t thread_index = 0;
+         thread_index < thread_count_ + 1;
+         ++thread_index) {
+      uint64_t thread_id;
+      int rv = ReadFD(read_fd, &thread_id, sizeof(thread_id));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(thread_id)), rv)
+          << ErrnoMessage("read");
+
+      TestThreadPool::ThreadExpectation expectation;
+      rv = ReadFD(read_fd,
+                  &expectation.stack_address,
+                  sizeof(expectation.stack_address));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.stack_address)), rv)
+          << ErrnoMessage("read");
+
+      rv = ReadFD(read_fd,
+                  &expectation.suspend_count,
+                  sizeof(expectation.suspend_count));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.suspend_count)), rv)
+          << ErrnoMessage("read");
+
+      // There can’t be any duplicate thread IDs.
+      EXPECT_EQ(0u, thread_map.count(thread_id));
+
+      thread_map[thread_id] = expectation;
+    }
+
+    const std::vector<ProcessReaderThread>& threads = process_reader.Threads();
+
+    // The child shouldn’t have any threads other than its main thread and the
+    // ones it created in its pool, so pass false for |tolerate_extra_threads|.
+    ExpectSeveralThreads(&thread_map, threads, false);
+
+    // Tell the child that it’s OK to exit. The child needed to be kept alive
+    // until the parent finished working with it.
+    int write_fd = WritePipeFD();
+    char c = '\0';
+    int rv = WriteFD(write_fd, &c, 1);
+    ASSERT_EQ(1, rv) << ErrnoMessage("write");
+  }
+
+  void Child() override {
+    TestThreadPool thread_pool;
+    thread_pool.StartThreads(thread_count_);
+    if (testing::Test::HasFatalFailure()) {
+      return;
+    }
+
+    int write_fd = WritePipeFD();
+
+    // This thread isn’t part of the thread pool, but the parent will be able
+    // to inspect it. Write an entry for it.
+    uint64_t thread_id = PthreadToThreadID(pthread_self());
+
+    int rv = WriteFD(write_fd, &thread_id, sizeof(thread_id));
+    ASSERT_EQ(static_cast<ssize_t>(sizeof(thread_id)), rv)
+        << ErrnoMessage("write");
+
+    TestThreadPool::ThreadExpectation expectation;
+    expectation.stack_address = reinterpret_cast<mach_vm_address_t>(&thread_id);
+    expectation.suspend_count = 0;
+
+    rv = WriteFD(write_fd,
+                 &expectation.stack_address,
+                 sizeof(expectation.stack_address));
+    ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.stack_address)), rv)
+        << ErrnoMessage("write");
+
+    rv = WriteFD(write_fd,
+                 &expectation.suspend_count,
+                 sizeof(expectation.suspend_count));
+    ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.suspend_count)), rv)
+        << ErrnoMessage("write");
+
+    // Write an entry for everything in the thread pool.
+    for (size_t thread_index = 0;
+         thread_index < thread_count_;
+         ++thread_index) {
+      uint64_t thread_id =
+          thread_pool.GetThreadInfo(thread_index, &expectation);
+
+      rv = WriteFD(write_fd, &thread_id, sizeof(thread_id));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(thread_id)), rv)
+          << ErrnoMessage("write");
+
+      rv = WriteFD(write_fd,
+                   &expectation.stack_address,
+                   sizeof(expectation.stack_address));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.stack_address)), rv)
+          << ErrnoMessage("write");
+
+      rv = WriteFD(write_fd,
+                   &expectation.suspend_count,
+                   sizeof(expectation.suspend_count));
+      ASSERT_EQ(static_cast<ssize_t>(sizeof(expectation.suspend_count)), rv)
+          << ErrnoMessage("write");
+    }
+
+    // Wait for the parent to say that it’s OK to exit.
+    int read_fd = ReadPipeFD();
+    char c;
+    rv = ReadFD(read_fd, &c, 1);
+    ASSERT_EQ(1, rv) << ErrnoMessage("read");
+  }
+
+ private:
+  size_t thread_count_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessReaderThreadedChild);
+};
+
+TEST(ProcessReader, ChildOneThread) {
+  // The main thread plus zero child threads equals one thread.
+  const size_t kChildThreads = 0;
+  ProcessReaderThreadedChild process_reader_threaded_child(kChildThreads);
+  process_reader_threaded_child.Run();
+}
+
+TEST(ProcessReader, ChildSeveralThreads) {
+  const size_t kChildThreads = 64;
+  ProcessReaderThreadedChild process_reader_threaded_child(kChildThreads);
+  process_reader_threaded_child.Run();
+}
+
+}  // namespace