Add a specialized LocalUnwinder object.

This object is for doing many local unwinds across different threads
at any point during a program's execution.

Also add LocalUpdatableMaps that will re-read the maps data under certain
circumstances.

This first version does not support jit or dex pc data.

Bug: 74361929

Test: Ran unit tests.
Change-Id: I790662366d3fed677f31b3288182950c494de9ad
diff --git a/libunwindstack/tests/LocalUnwinderTest.cpp b/libunwindstack/tests/LocalUnwinderTest.cpp
new file mode 100644
index 0000000..56a18cd
--- /dev/null
+++ b/libunwindstack/tests/LocalUnwinderTest.cpp
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * 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 <dlfcn.h>
+#include <inttypes.h>
+#include <signal.h>
+#include <stdint.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include <gtest/gtest.h>
+
+#include <android-base/stringprintf.h>
+
+#include <unwindstack/LocalUnwinder.h>
+
+namespace unwindstack {
+
+static std::vector<LocalFrameData>* g_frame_info;
+static LocalUnwinder* g_unwinder;
+
+extern "C" void SignalLocalInnerFunction() {
+  g_unwinder->Unwind(g_frame_info, 256);
+}
+
+extern "C" void SignalLocalMiddleFunction() {
+  SignalLocalInnerFunction();
+}
+
+extern "C" void SignalLocalOuterFunction() {
+  SignalLocalMiddleFunction();
+}
+
+static void SignalLocalCallerHandler(int, siginfo_t*, void*) {
+  SignalLocalOuterFunction();
+}
+
+static std::string ErrorMsg(const std::vector<const char*>& function_names,
+                            const std::vector<LocalFrameData>& frame_info) {
+  std::string unwind;
+  size_t i = 0;
+  for (const auto& frame : frame_info) {
+    unwind += android::base::StringPrintf("#%02zu pc 0x%" PRIx64 " rel_pc 0x%" PRIx64, i++,
+                                          frame.pc, frame.rel_pc);
+    if (frame.map_info != nullptr) {
+      if (!frame.map_info->name.empty()) {
+        unwind += " " + frame.map_info->name;
+      } else {
+        unwind += android::base::StringPrintf(" 0x%" PRIx64 "-0x%" PRIx64, frame.map_info->start,
+                                              frame.map_info->end);
+      }
+      if (frame.map_info->offset != 0) {
+        unwind += android::base::StringPrintf(" offset 0x%" PRIx64, frame.map_info->offset);
+      }
+    }
+    if (!frame.function_name.empty()) {
+      unwind += " " + frame.function_name;
+      if (frame.function_offset != 0) {
+        unwind += android::base::StringPrintf("+%" PRId64, frame.function_offset);
+      }
+    }
+    unwind += '\n';
+  }
+
+  return std::string(
+             "Unwind completed without finding all frames\n"
+             "  Looking for function: ") +
+         function_names.front() + "\n" + "Unwind data:\n" + unwind;
+}
+
+// This test assumes that this code is compiled with optimizations turned
+// off. If this doesn't happen, then all of the calls will be optimized
+// away.
+extern "C" void LocalInnerFunction(LocalUnwinder* unwinder, bool unwind_through_signal) {
+  std::vector<LocalFrameData> frame_info;
+  g_frame_info = &frame_info;
+  g_unwinder = unwinder;
+  std::vector<const char*> expected_function_names;
+
+  if (unwind_through_signal) {
+    struct sigaction act, oldact;
+    memset(&act, 0, sizeof(act));
+    act.sa_sigaction = SignalLocalCallerHandler;
+    act.sa_flags = SA_RESTART | SA_ONSTACK;
+    ASSERT_EQ(0, sigaction(SIGUSR1, &act, &oldact));
+
+    raise(SIGUSR1);
+
+    ASSERT_EQ(0, sigaction(SIGUSR1, &oldact, nullptr));
+
+    expected_function_names = {"LocalOuterFunction",        "LocalMiddleFunction",
+                               "LocalInnerFunction",        "SignalLocalOuterFunction",
+                               "SignalLocalMiddleFunction", "SignalLocalInnerFunction"};
+  } else {
+    ASSERT_TRUE(unwinder->Unwind(&frame_info, 256));
+
+    expected_function_names = {"LocalOuterFunction", "LocalMiddleFunction", "LocalInnerFunction"};
+  }
+
+  for (auto& frame : frame_info) {
+    if (frame.function_name == expected_function_names.back()) {
+      expected_function_names.pop_back();
+      if (expected_function_names.empty()) {
+        break;
+      }
+    }
+  }
+
+  ASSERT_TRUE(expected_function_names.empty()) << ErrorMsg(expected_function_names, frame_info);
+}
+
+extern "C" void LocalMiddleFunction(LocalUnwinder* unwinder, bool unwind_through_signal) {
+  LocalInnerFunction(unwinder, unwind_through_signal);
+}
+
+extern "C" void LocalOuterFunction(LocalUnwinder* unwinder, bool unwind_through_signal) {
+  LocalMiddleFunction(unwinder, unwind_through_signal);
+}
+
+class LocalUnwinderTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    unwinder_.reset(new LocalUnwinder);
+    ASSERT_TRUE(unwinder_->Init());
+  }
+
+  std::unique_ptr<LocalUnwinder> unwinder_;
+};
+
+TEST_F(LocalUnwinderTest, local) {
+  LocalOuterFunction(unwinder_.get(), false);
+}
+
+TEST_F(LocalUnwinderTest, local_signal) {
+  LocalOuterFunction(unwinder_.get(), true);
+}
+
+TEST_F(LocalUnwinderTest, local_multiple) {
+  ASSERT_NO_FATAL_FAILURE(LocalOuterFunction(unwinder_.get(), false));
+
+  ASSERT_NO_FATAL_FAILURE(LocalOuterFunction(unwinder_.get(), true));
+
+  ASSERT_NO_FATAL_FAILURE(LocalOuterFunction(unwinder_.get(), false));
+
+  ASSERT_NO_FATAL_FAILURE(LocalOuterFunction(unwinder_.get(), true));
+}
+
+// This test verifies that doing an unwind before and after a dlopen
+// works. It's verifying that the maps read during the first unwind
+// do not cause a problem when doing the unwind using the code in
+// the dlopen'd code.
+TEST_F(LocalUnwinderTest, unwind_after_dlopen) {
+  // Prime the maps data.
+  ASSERT_NO_FATAL_FAILURE(LocalOuterFunction(unwinder_.get(), false));
+
+  std::string testlib(testing::internal::GetArgvs()[0]);
+  auto const value = testlib.find_last_of('/');
+  if (value == std::string::npos) {
+    testlib = "../";
+  } else {
+    testlib = testlib.substr(0, value + 1) + "../";
+  }
+  testlib += "libunwindstack_local.so";
+
+  void* handle = dlopen(testlib.c_str(), RTLD_NOW);
+  ASSERT_TRUE(handle != nullptr);
+
+  void (*unwind_function)(void*, void*) =
+      reinterpret_cast<void (*)(void*, void*)>(dlsym(handle, "TestlibLevel1"));
+  ASSERT_TRUE(unwind_function != nullptr);
+
+  std::vector<LocalFrameData> frame_info;
+  unwind_function(unwinder_.get(), &frame_info);
+
+  ASSERT_EQ(0, dlclose(handle));
+
+  std::vector<const char*> expected_function_names{"TestlibLevel1", "TestlibLevel2",
+                                                   "TestlibLevel3", "TestlibLevel4"};
+
+  for (auto& frame : frame_info) {
+    if (frame.function_name == expected_function_names.back()) {
+      expected_function_names.pop_back();
+      if (expected_function_names.empty()) {
+        break;
+      }
+    }
+  }
+
+  ASSERT_TRUE(expected_function_names.empty()) << ErrorMsg(expected_function_names, frame_info);
+}
+
+}  // namespace unwindstack