| /* |
| * Copyright (C) 2020 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 <gtest/gtest.h> |
| |
| #if defined(__BIONIC__) |
| |
| #include <sys/mman.h> |
| |
| #include "platform/bionic/android_unsafe_frame_pointer_chase.h" |
| |
| // Prevent tail calls inside recurse. |
| __attribute__((weak, noinline)) size_t nop(size_t val) { |
| return val; |
| } |
| |
| // Call android_unsafe_frame_pointer_chase inside count recurse stack frames. |
| __attribute__((weak, noinline)) int recurse(int count, uintptr_t* buf, size_t num_entries) { |
| if (count != 0) return nop(recurse(count - 1, buf, num_entries)); |
| return nop(android_unsafe_frame_pointer_chase(buf, num_entries)); |
| } |
| |
| static constexpr size_t kNumFrames = 32; |
| |
| static bool CheckFrames(uintptr_t* frames, size_t num_frames) { |
| // We expect one recurse frame calling android_unsafe_frame_pointer_chase, followed by kNumFrames identical |
| // recurse frames calling themselves, followed by at least one frame (the first caller of |
| // recurse). |
| if (num_frames < kNumFrames + 2) { |
| printf("num_frames (0x%zu) < kNumFrames + 2", num_frames); |
| return false; |
| } |
| |
| if (frames[0] == frames[1]) { |
| printf("frames[0] == frames[1] (0x%zx)", frames[0]); |
| return false; |
| } |
| |
| for (size_t i = 2; i <= kNumFrames; ++i) { |
| if (frames[i] != frames[1]) { |
| printf("frames[i] (0x%zx) != frames[1] (0x%zx)", frames[i], frames[1]); |
| return false; |
| } |
| } |
| |
| if (frames[kNumFrames] == frames[kNumFrames + 1]) { |
| printf("frames[kNumFrames] == frames[kNumFrames + 1] (0x%zx)", frames[kNumFrames]); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| TEST(android_unsafe_frame_pointer_chase, main_thread) { |
| size_t size = recurse(kNumFrames, 0, 0); |
| |
| uintptr_t frames[kNumFrames + 2]; |
| size_t size2 = recurse(kNumFrames, frames, kNumFrames + 2); |
| EXPECT_EQ(size2, size); |
| |
| EXPECT_TRUE(CheckFrames(frames, size)); |
| } |
| |
| static const char* tester_func() { |
| size_t size = recurse(kNumFrames, 0, 0); |
| |
| uintptr_t frames[kNumFrames + 2]; |
| size_t size2 = recurse(kNumFrames, frames, kNumFrames + 2); |
| if (size2 != size) { |
| return "size2 != size"; |
| } |
| |
| if (!CheckFrames(frames, size)) { |
| return "CheckFrames failed"; |
| } |
| return nullptr; |
| } |
| |
| static void* BacktraceThread(void*) { |
| return (void*)tester_func(); |
| } |
| |
| TEST(android_unsafe_frame_pointer_chase, pthread) { |
| pthread_t t; |
| ASSERT_EQ(0, pthread_create(&t, nullptr, BacktraceThread, nullptr)); |
| void* retval; |
| ASSERT_EQ(0, pthread_join(t, &retval)); |
| EXPECT_EQ(nullptr, reinterpret_cast<char*>(retval)); |
| } |
| |
| static bool g_handler_called; |
| static const char* g_handler_tester_result; |
| |
| static void BacktraceHandler(int) { |
| g_handler_called = true; |
| g_handler_tester_result = tester_func(); |
| } |
| |
| static constexpr size_t kStackSize = 16384; |
| |
| static void* SignalBacktraceThread(void* sp) { |
| stack_t ss; |
| ss.ss_sp = sp; |
| ss.ss_flags = 0; |
| ss.ss_size = kStackSize; |
| sigaltstack(&ss, nullptr); |
| |
| struct sigaction s = {}; |
| s.sa_handler = BacktraceHandler; |
| s.sa_flags = SA_ONSTACK; |
| sigaction(SIGRTMIN, &s, nullptr); |
| |
| raise(SIGRTMIN); |
| return nullptr; |
| } |
| |
| TEST(android_unsafe_frame_pointer_chase, sigaltstack) { |
| // Create threads where the alternate stack appears both after and before the regular stack, and |
| // call android_unsafe_frame_pointer_chase from a signal handler. Without handling for the |
| // alternate signal stack, this would cause false negatives or potential false positives in the |
| // android_unsafe_frame_pointer_chase function. |
| void* stacks = |
| mmap(nullptr, kStackSize * 2, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0); |
| |
| for (unsigned i = 0; i != 2; ++i) { |
| pthread_t t; |
| pthread_attr_t attr; |
| ASSERT_EQ(0, pthread_attr_init(&attr)); |
| ASSERT_EQ(0, pthread_attr_setstack(&attr, reinterpret_cast<char*>(stacks) + kStackSize * i, |
| kStackSize)); |
| |
| ASSERT_EQ(0, pthread_create(&t, &attr, SignalBacktraceThread, |
| reinterpret_cast<char*>(stacks) + kStackSize * (1 - i))); |
| void* retval; |
| ASSERT_EQ(0, pthread_join(t, &retval)); |
| |
| EXPECT_TRUE(g_handler_called); |
| EXPECT_EQ(nullptr, g_handler_tester_result); |
| g_handler_called = false; |
| } |
| |
| munmap(stacks, kStackSize * 2); |
| } |
| |
| #endif // __BIONIC__ |