| // 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 "client/capture_context_mac.h" |
| |
| #include <mach/mach.h> |
| #include <stdint.h> |
| |
| #include <algorithm> |
| |
| #include "build/build_config.h" |
| #include "gtest/gtest.h" |
| #include "util/misc/address_sanitizer.h" |
| #include "util/misc/implicit_cast.h" |
| |
| namespace crashpad { |
| namespace test { |
| namespace { |
| |
| // If the context structure has fields that tell whether it’s valid, such as |
| // magic numbers or size fields, sanity-checks those fields for validity with |
| // fatal gtest assertions. For other fields, where it’s possible to reason about |
| // their validity based solely on their contents, sanity-checks via nonfatal |
| // gtest assertions. |
| void SanityCheckContext(const NativeCPUContext& context) { |
| #if defined(ARCH_CPU_X86) |
| ASSERT_EQ(implicit_cast<thread_state_flavor_t>(context.tsh.flavor), |
| implicit_cast<thread_state_flavor_t>(x86_THREAD_STATE32)); |
| ASSERT_EQ(implicit_cast<uint32_t>(context.tsh.count), |
| implicit_cast<uint32_t>(x86_THREAD_STATE32_COUNT)); |
| #elif defined(ARCH_CPU_X86_64) |
| ASSERT_EQ(implicit_cast<thread_state_flavor_t>(context.tsh.flavor), |
| implicit_cast<thread_state_flavor_t>(x86_THREAD_STATE64)); |
| ASSERT_EQ(implicit_cast<uint32_t>(context.tsh.count), |
| implicit_cast<uint32_t>(x86_THREAD_STATE64_COUNT)); |
| #endif |
| |
| #if defined(ARCH_CPU_X86_FAMILY) |
| // The segment registers are only capable of storing 16-bit quantities, but |
| // the context structure provides native integer-width fields for them. Ensure |
| // that the high bits are all clear. |
| // |
| // Many bit positions in the flags register are reserved and will always read |
| // a known value. Most reserved bits are always 0, but bit 1 is always 1. |
| // Check that the reserved bits are all set to their expected values. Note |
| // that the set of reserved bits may be relaxed over time with newer CPUs, and |
| // that this test may need to be changed to reflect these developments. The |
| // current set of reserved bits are 1, 3, 5, 15, and 22 and higher. See Intel |
| // Software Developer’s Manual, Volume 1: Basic Architecture (253665-051), |
| // 3.4.3 “EFLAGS Register”, and AMD Architecture Programmer’s Manual, Volume |
| // 2: System Programming (24593-3.24), 3.1.6 “RFLAGS Register”. |
| #if defined(ARCH_CPU_X86) |
| EXPECT_EQ(context.uts.ts32.__cs & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__ds & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__es & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__fs & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__gs & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__ss & ~0xffff, 0u); |
| EXPECT_EQ(context.uts.ts32.__eflags & 0xffc0802a, 2u); |
| #elif defined(ARCH_CPU_X86_64) |
| EXPECT_EQ(context.uts.ts64.__cs & ~UINT64_C(0xffff), 0u); |
| EXPECT_EQ(context.uts.ts64.__fs & ~UINT64_C(0xffff), 0u); |
| EXPECT_EQ(context.uts.ts64.__gs & ~UINT64_C(0xffff), 0u); |
| EXPECT_EQ(context.uts.ts64.__rflags & UINT64_C(0xffffffffffc0802a), 2u); |
| #endif |
| #endif |
| } |
| |
| // A CPU-independent function to return the program counter. |
| uintptr_t ProgramCounterFromContext(const NativeCPUContext& context) { |
| #if defined(ARCH_CPU_X86) |
| return context.uts.ts32.__eip; |
| #elif defined(ARCH_CPU_X86_64) |
| return context.uts.ts64.__rip; |
| #endif |
| } |
| |
| // A CPU-independent function to return the stack pointer. |
| uintptr_t StackPointerFromContext(const NativeCPUContext& context) { |
| #if defined(ARCH_CPU_X86) |
| return context.uts.ts32.__esp; |
| #elif defined(ARCH_CPU_X86_64) |
| return context.uts.ts64.__rsp; |
| #endif |
| } |
| |
| void TestCaptureContext() { |
| NativeCPUContext context_1; |
| CaptureContext(&context_1); |
| |
| { |
| SCOPED_TRACE("context_1"); |
| ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_1)); |
| } |
| |
| // The program counter reference value is this function’s address. The |
| // captured program counter should be slightly greater than or equal to the |
| // reference program counter. |
| uintptr_t pc = ProgramCounterFromContext(context_1); |
| |
| #if !defined(ADDRESS_SANITIZER) |
| // AddressSanitizer can cause enough code bloat that the “nearby” check would |
| // likely fail. |
| const uintptr_t kReferencePC = |
| reinterpret_cast<uintptr_t>(TestCaptureContext); |
| EXPECT_LT(pc - kReferencePC, 64u); |
| #endif // !defined(ADDRESS_SANITIZER) |
| |
| // Declare sp and context_2 here because all local variables need to be |
| // declared before computing the stack pointer reference value, so that the |
| // reference value can be the lowest value possible. |
| uintptr_t sp; |
| NativeCPUContext context_2; |
| |
| // The stack pointer reference value is the lowest address of a local variable |
| // in this function. The captured program counter will be slightly less than |
| // or equal to the reference stack pointer. |
| const uintptr_t kReferenceSP = |
| std::min(std::min(reinterpret_cast<uintptr_t>(&context_1), |
| reinterpret_cast<uintptr_t>(&context_2)), |
| std::min(reinterpret_cast<uintptr_t>(&pc), |
| reinterpret_cast<uintptr_t>(&sp))); |
| sp = StackPointerFromContext(context_1); |
| EXPECT_LT(kReferenceSP - sp, 512u); |
| |
| // Capture the context again, expecting that the stack pointer stays the same |
| // and the program counter increases. Strictly speaking, there’s no guarantee |
| // that these conditions will hold, although they do for known compilers even |
| // under typical optimization. |
| CaptureContext(&context_2); |
| |
| { |
| SCOPED_TRACE("context_2"); |
| ASSERT_NO_FATAL_FAILURE(SanityCheckContext(context_2)); |
| } |
| |
| EXPECT_EQ(StackPointerFromContext(context_2), sp); |
| EXPECT_GT(ProgramCounterFromContext(context_2), pc); |
| } |
| |
| TEST(CaptureContextMac, CaptureContext) { |
| ASSERT_NO_FATAL_FAILURE(TestCaptureContext()); |
| } |
| |
| } // namespace |
| } // namespace test |
| } // namespace crashpad |