// Copyright 2018 The gVisor Authors. // // 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. #ifndef GVISOR_TEST_UTIL_SIGNAL_UTIL_H_ #define GVISOR_TEST_UTIL_SIGNAL_UTIL_H_ #include <signal.h> #include <sys/syscall.h> #include <unistd.h> #include <ostream> #include "gmock/gmock.h" #include "test/util/cleanup.h" #include "test/util/posix_error.h" // Format a sigset_t as a comma separated list of numeric ranges. ::std::ostream& operator<<(::std::ostream& os, const sigset_t& sigset); namespace gvisor { namespace testing { // The maximum signal number. static constexpr int kMaxSignal = 64; // Wrapper for the tgkill(2) syscall, which glibc does not provide. inline int tgkill(pid_t tgid, pid_t tid, int sig) { return syscall(__NR_tgkill, tgid, tid, sig); } // Installs the passed sigaction and returns a cleanup function to restore the // previous handler when it goes out of scope. PosixErrorOr<Cleanup> ScopedSigaction(int sig, struct sigaction const& sa); // Updates the signal mask as per sigprocmask(2) and returns a cleanup function // to restore the previous signal mask when it goes out of scope. PosixErrorOr<Cleanup> ScopedSignalMask(int how, sigset_t const& set); // ScopedSignalMask variant that creates a mask of the single signal 'sig'. inline PosixErrorOr<Cleanup> ScopedSignalMask(int how, int sig) { sigset_t set; sigemptyset(&set); sigaddset(&set, sig); return ScopedSignalMask(how, set); } // Asserts equality of two sigset_t values. MATCHER_P(EqualsSigset, value, "equals " + ::testing::PrintToString(value)) { for (int sig = 1; sig <= kMaxSignal; ++sig) { if (sigismember(&arg, sig) != sigismember(&value, sig)) { return false; } } return true; } #ifdef __x86_64__ // Fault can be used to generate a synchronous SIGSEGV. // // This fault can be fixed up in a handler via fixup, below. inline void Fault() { // Zero and dereference %ax. asm("movabs $0, %%rax\r\n" "mov 0(%%rax), %%rax\r\n" : : : "ax"); } // FixupFault fixes up a fault generated by fault, above. inline void FixupFault(ucontext_t* ctx) { // Skip the bad instruction above. // // The encoding is 0x48 0xab 0x00. ctx->uc_mcontext.gregs[REG_RIP] += 3; } #elif __aarch64__ inline void Fault() { // Zero and dereference x0. asm("mov xzr, x0\r\n" "str xzr, [x0]\r\n" : : : "x0"); } inline void FixupFault(ucontext_t* ctx) { // Skip the bad instruction above. ctx->uc_mcontext.pc += 4; } #endif } // namespace testing } // namespace gvisor #endif // GVISOR_TEST_UTIL_SIGNAL_UTIL_H_