| /* |
| * Copyright (C) 2016 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 <sys/ptrace.h> |
| |
| #include <elf.h> |
| #include <sched.h> |
| #include <sys/prctl.h> |
| #include <sys/uio.h> |
| #include <sys/user.h> |
| #include <unistd.h> |
| |
| #include <gtest/gtest.h> |
| |
| // Host libc does not define this. |
| #ifndef TRAP_HWBKPT |
| #define TRAP_HWBKPT 4 |
| #endif |
| |
| template<typename T> |
| static void __attribute__((noreturn)) fork_child(unsigned cpu, T &data) { |
| // Extra precaution: make sure we go away if anything happens to our parent. |
| if (prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0) == -1) { |
| perror("prctl(PR_SET_PDEATHSIG)"); |
| _exit(1); |
| } |
| |
| cpu_set_t cpus; |
| CPU_ZERO(&cpus); |
| CPU_SET(cpu, &cpus); |
| if (sched_setaffinity(0, sizeof cpus, &cpus) == -1) { |
| perror("sched_setaffinity"); |
| _exit(2); |
| } |
| if (ptrace(PTRACE_TRACEME, 0, nullptr, nullptr) == -1) { |
| perror("ptrace(PTRACE_TRACEME)"); |
| _exit(3); |
| } |
| |
| raise(SIGSTOP); // Synchronize with the tracer, let it set the watchpoint. |
| |
| data = 1; // Now trigger the watchpoint. |
| |
| _exit(0); |
| } |
| |
| class ChildGuard { |
| public: |
| explicit ChildGuard(pid_t pid) : pid(pid) {} |
| |
| ~ChildGuard() { |
| kill(pid, SIGKILL); |
| int status; |
| waitpid(pid, &status, 0); |
| } |
| |
| private: |
| pid_t pid; |
| }; |
| |
| static bool are_watchpoints_supported(pid_t child) { |
| #if defined(__arm__) |
| long capabilities; |
| long result = ptrace(PTRACE_GETHBPREGS, child, 0, &capabilities); |
| if (result == -1) { |
| EXPECT_EQ(EIO, errno); |
| return false; |
| } |
| return ((capabilities >> 8) & 0xff) > 0; |
| #elif defined(__aarch64__) |
| user_hwdebug_state dreg_state; |
| iovec iov; |
| iov.iov_base = &dreg_state; |
| iov.iov_len = sizeof(dreg_state); |
| |
| long result = ptrace(PTRACE_GETREGSET, child, NT_ARM_HW_WATCH, &iov); |
| if (result == -1) { |
| EXPECT_EQ(EINVAL, errno); |
| return false; |
| } |
| return (dreg_state.dbg_info & 0xff) > 0; |
| #elif defined(__i386__) || defined(__x86_64__) |
| // We assume watchpoints are always supported on x86. |
| (void) child; |
| return true; |
| #else |
| // TODO: mips support. |
| (void) child; |
| return false; |
| #endif |
| } |
| |
| static void set_watchpoint(pid_t child, const void *address, size_t size) { |
| #if defined(__arm__) || defined(__aarch64__) |
| const unsigned byte_mask = (1 << size) - 1; |
| const unsigned type = 2; // Write. |
| const unsigned enable = 1; |
| const unsigned control = byte_mask << 5 | type << 3 | enable; |
| |
| #ifdef __arm__ |
| ASSERT_EQ(0, ptrace(PTRACE_SETHBPREGS, child, -1, &address)) << strerror(errno); |
| ASSERT_EQ(0, ptrace(PTRACE_SETHBPREGS, child, -2, &control)) << strerror(errno); |
| #else // aarch64 |
| user_hwdebug_state dreg_state; |
| memset(&dreg_state, 0, sizeof dreg_state); |
| dreg_state.dbg_regs[0].addr = reinterpret_cast<uintptr_t>(address); |
| dreg_state.dbg_regs[0].ctrl = control; |
| |
| iovec iov; |
| iov.iov_base = &dreg_state; |
| iov.iov_len = offsetof(user_hwdebug_state, dbg_regs) + sizeof(dreg_state.dbg_regs[0]); |
| |
| ASSERT_EQ(0, ptrace(PTRACE_SETREGSET, child, NT_ARM_HW_WATCH, &iov)) << strerror(errno); |
| #endif |
| #elif defined(__i386__) || defined(__x86_64__) |
| ASSERT_EQ(0, ptrace(PTRACE_POKEUSER, child, offsetof(user, u_debugreg[0]), address)) << strerror(errno); |
| errno = 0; |
| unsigned data = ptrace(PTRACE_PEEKUSER, child, offsetof(user, u_debugreg[7]), nullptr); |
| ASSERT_EQ(0, errno); |
| |
| const unsigned size_flag = (size == 8) ? 2 : size - 1; |
| const unsigned enable = 1; |
| const unsigned type = 1; // Write. |
| |
| const unsigned mask = 3 << 18 | 3 << 16 | 1; |
| const unsigned value = size_flag << 18 | type << 16 | enable; |
| data &= mask; |
| data |= value; |
| ASSERT_EQ(0, ptrace(PTRACE_POKEUSER, child, offsetof(user, u_debugreg[7]), data)) << strerror(errno); |
| #else |
| (void) child; |
| (void) address; |
| (void) size; |
| #endif |
| } |
| |
| template<typename T> |
| static void run_watchpoint_test_impl(unsigned cpu) { |
| alignas(8) T data = 0; |
| |
| pid_t child = fork(); |
| ASSERT_NE(-1, child) << strerror(errno); |
| if (child == 0) fork_child(cpu, data); |
| |
| ChildGuard guard(child); |
| |
| int status; |
| ASSERT_EQ(child, waitpid(child, &status, __WALL)) << strerror(errno); |
| ASSERT_TRUE(WIFSTOPPED(status)) << "Status was: " << status; |
| ASSERT_EQ(SIGSTOP, WSTOPSIG(status)) << "Status was: " << status; |
| |
| if (!are_watchpoints_supported(child)) return; |
| |
| set_watchpoint(child, &data, sizeof data); |
| |
| ASSERT_EQ(0, ptrace(PTRACE_CONT, child, nullptr, nullptr)) << strerror(errno); |
| ASSERT_EQ(child, waitpid(child, &status, __WALL)) << strerror(errno); |
| ASSERT_TRUE(WIFSTOPPED(status)) << "Status was: " << status; |
| ASSERT_EQ(SIGTRAP, WSTOPSIG(status)) << "Status was: " << status; |
| |
| siginfo_t siginfo; |
| ASSERT_EQ(0, ptrace(PTRACE_GETSIGINFO, child, nullptr, &siginfo)) << strerror(errno); |
| ASSERT_EQ(TRAP_HWBKPT, siginfo.si_code); |
| #if defined(__arm__) || defined(__aarch64__) |
| ASSERT_EQ(&data, siginfo.si_addr); |
| #endif |
| } |
| |
| static void run_watchpoint_test(unsigned cpu) { |
| run_watchpoint_test_impl<uint8_t>(cpu); |
| run_watchpoint_test_impl<uint16_t>(cpu); |
| run_watchpoint_test_impl<uint32_t>(cpu); |
| #if defined(__LP64__) |
| run_watchpoint_test_impl<uint64_t>(cpu); |
| #endif |
| } |
| |
| // Test watchpoint API. The test is considered successful if our watchpoints get hit OR the |
| // system reports that watchpoint support is not present. We run the test for different |
| // watchpoint sizes, while pinning the process to each cpu in turn, for better coverage. |
| TEST(ptrace, watchpoint_stress) { |
| cpu_set_t available_cpus; |
| ASSERT_EQ(0, sched_getaffinity(0, sizeof available_cpus, &available_cpus)); |
| |
| for (size_t cpu = 0; cpu < CPU_SETSIZE; ++cpu) { |
| if (!CPU_ISSET(cpu, &available_cpus)) continue; |
| run_watchpoint_test(cpu); |
| } |
| } |