diff options
Diffstat (limited to 'comm/third_party/botan/src/lib/utils/os_utils.cpp')
| -rw-r--r-- | comm/third_party/botan/src/lib/utils/os_utils.cpp | 757 |
1 files changed, 757 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/utils/os_utils.cpp b/comm/third_party/botan/src/lib/utils/os_utils.cpp new file mode 100644 index 0000000000..f5151da42b --- /dev/null +++ b/comm/third_party/botan/src/lib/utils/os_utils.cpp @@ -0,0 +1,757 @@ +/* +* OS and machine specific utility functions +* (C) 2015,2016,2017,2018 Jack Lloyd +* (C) 2016 Daniel Neus +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/internal/os_utils.h> +#include <botan/cpuid.h> +#include <botan/exceptn.h> +#include <botan/mem_ops.h> + +#include <algorithm> +#include <chrono> +#include <cstdlib> + +#if defined(BOTAN_TARGET_OS_HAS_THREADS) + #include <thread> +#endif + +#if defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO) + #include <string.h> +#endif + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + #include <sys/types.h> + #include <sys/resource.h> + #include <sys/mman.h> + #include <signal.h> + #include <stdlib.h> + #include <setjmp.h> + #include <unistd.h> + #include <errno.h> + #include <termios.h> + #undef B0 +#endif + +#if defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN) + #include <emscripten/emscripten.h> +#endif + +#if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL) || defined(BOTAN_TARGET_OS_IS_ANDROID) || \ + defined(BOTAN_TARGET_OS_HAS_ELF_AUX_INFO) + #include <sys/auxv.h> +#endif + +#if defined(BOTAN_TARGET_OS_HAS_WIN32) + #define NOMINMAX 1 + #define _WINSOCKAPI_ // stop windows.h including winsock.h + #include <windows.h> +#endif + +#if defined(BOTAN_TARGET_OS_IS_ANDROID) + #include <elf.h> + extern "C" char **environ; +#endif + +#if defined(BOTAN_TARGET_OS_IS_IOS) || defined(BOTAN_TARGET_OS_IS_MACOS) + #include <mach/vm_statistics.h> +#endif + +namespace Botan { + +// Not defined in OS namespace for historical reasons +void secure_scrub_memory(void* ptr, size_t n) + { +#if defined(BOTAN_TARGET_OS_HAS_RTLSECUREZEROMEMORY) + ::RtlSecureZeroMemory(ptr, n); + +#elif defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO) + ::explicit_bzero(ptr, n); + +#elif defined(BOTAN_TARGET_OS_HAS_EXPLICIT_MEMSET) + (void)::explicit_memset(ptr, 0, n); + +#elif defined(BOTAN_USE_VOLATILE_MEMSET_FOR_ZERO) && (BOTAN_USE_VOLATILE_MEMSET_FOR_ZERO == 1) + /* + Call memset through a static volatile pointer, which the compiler + should not elide. This construct should be safe in conforming + compilers, but who knows. I did confirm that on x86-64 GCC 6.1 and + Clang 3.8 both create code that saves the memset address in the + data segment and unconditionally loads and jumps to that address. + */ + static void* (*const volatile memset_ptr)(void*, int, size_t) = std::memset; + (memset_ptr)(ptr, 0, n); +#else + + volatile uint8_t* p = reinterpret_cast<volatile uint8_t*>(ptr); + + for(size_t i = 0; i != n; ++i) + p[i] = 0; +#endif + } + +uint32_t OS::get_process_id() + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + return ::getpid(); +#elif defined(BOTAN_TARGET_OS_HAS_WIN32) + return ::GetCurrentProcessId(); +#elif defined(BOTAN_TARGET_OS_IS_INCLUDEOS) || defined(BOTAN_TARGET_OS_IS_LLVM) || defined(BOTAN_TARGET_OS_IS_NONE) + return 0; // truly no meaningful value +#else + #error "Missing get_process_id" +#endif + } + +unsigned long OS::get_auxval(unsigned long id) + { +#if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL) + return ::getauxval(id); +#elif defined(BOTAN_TARGET_OS_IS_ANDROID) && defined(BOTAN_TARGET_ARCH_IS_ARM32) + + if(id == 0) + return 0; + + char **p = environ; + + while(*p++ != nullptr) + ; + + Elf32_auxv_t *e = reinterpret_cast<Elf32_auxv_t*>(p); + + while(e != nullptr) + { + if(e->a_type == id) + return e->a_un.a_val; + e++; + } + + return 0; +#elif defined(BOTAN_TARGET_OS_HAS_ELF_AUX_INFO) + unsigned long auxinfo = 0; + ::elf_aux_info(id, &auxinfo, sizeof(auxinfo)); + return auxinfo; +#else + BOTAN_UNUSED(id); + return 0; +#endif + } + +bool OS::running_in_privileged_state() + { +#if defined(AT_SECURE) + return OS::get_auxval(AT_SECURE) != 0; +#elif defined(BOTAN_TARGET_OS_HAS_POSIX1) + return (::getuid() != ::geteuid()) || (::getgid() != ::getegid()); +#else + return false; +#endif + } + +uint64_t OS::get_cpu_cycle_counter() + { + uint64_t rtc = 0; + +#if defined(BOTAN_TARGET_OS_HAS_WIN32) + LARGE_INTEGER tv; + ::QueryPerformanceCounter(&tv); + rtc = tv.QuadPart; + +#elif defined(BOTAN_USE_GCC_INLINE_ASM) + +#if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY) + + if(CPUID::has_rdtsc()) + { + uint32_t rtc_low = 0, rtc_high = 0; + asm volatile("rdtsc" : "=d" (rtc_high), "=a" (rtc_low)); + rtc = (static_cast<uint64_t>(rtc_high) << 32) | rtc_low; + } + +#elif defined(BOTAN_TARGET_ARCH_IS_PPC64) + + for(;;) + { + uint32_t rtc_low = 0, rtc_high = 0, rtc_high2 = 0; + asm volatile("mftbu %0" : "=r" (rtc_high)); + asm volatile("mftb %0" : "=r" (rtc_low)); + asm volatile("mftbu %0" : "=r" (rtc_high2)); + + if(rtc_high == rtc_high2) + { + rtc = (static_cast<uint64_t>(rtc_high) << 32) | rtc_low; + break; + } + } + +#elif defined(BOTAN_TARGET_ARCH_IS_ALPHA) + asm volatile("rpcc %0" : "=r" (rtc)); + + // OpenBSD does not trap access to the %tick register +#elif defined(BOTAN_TARGET_ARCH_IS_SPARC64) && !defined(BOTAN_TARGET_OS_IS_OPENBSD) + asm volatile("rd %%tick, %0" : "=r" (rtc)); + +#elif defined(BOTAN_TARGET_ARCH_IS_IA64) + asm volatile("mov %0=ar.itc" : "=r" (rtc)); + +#elif defined(BOTAN_TARGET_ARCH_IS_S390X) + asm volatile("stck 0(%0)" : : "a" (&rtc) : "memory", "cc"); + +#elif defined(BOTAN_TARGET_ARCH_IS_HPPA) + asm volatile("mfctl 16,%0" : "=r" (rtc)); // 64-bit only? + +#else + //#warning "OS::get_cpu_cycle_counter not implemented" +#endif + +#endif + + return rtc; + } + +size_t OS::get_cpu_total() + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(_SC_NPROCESSORS_CONF) + const long res = ::sysconf(_SC_NPROCESSORS_CONF); + if(res > 0) + return static_cast<size_t>(res); +#endif + +#if defined(BOTAN_TARGET_OS_HAS_THREADS) + return static_cast<size_t>(std::thread::hardware_concurrency()); +#else + return 1; +#endif + } + +size_t OS::get_cpu_available() + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(_SC_NPROCESSORS_ONLN) + const long res = ::sysconf(_SC_NPROCESSORS_ONLN); + if(res > 0) + return static_cast<size_t>(res); +#endif + + return OS::get_cpu_total(); + } + +uint64_t OS::get_high_resolution_clock() + { + if(uint64_t cpu_clock = OS::get_cpu_cycle_counter()) + return cpu_clock; + +#if defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN) + return emscripten_get_now(); +#endif + + /* + If we got here either we either don't have an asm instruction + above, or (for x86) RDTSC is not available at runtime. Try some + clock_gettimes and return the first one that works, or otherwise + fall back to std::chrono. + */ + +#if defined(BOTAN_TARGET_OS_HAS_CLOCK_GETTIME) + + // The ordering here is somewhat arbitrary... + const clockid_t clock_types[] = { +#if defined(CLOCK_MONOTONIC_HR) + CLOCK_MONOTONIC_HR, +#endif +#if defined(CLOCK_MONOTONIC_RAW) + CLOCK_MONOTONIC_RAW, +#endif +#if defined(CLOCK_MONOTONIC) + CLOCK_MONOTONIC, +#endif +#if defined(CLOCK_PROCESS_CPUTIME_ID) + CLOCK_PROCESS_CPUTIME_ID, +#endif +#if defined(CLOCK_THREAD_CPUTIME_ID) + CLOCK_THREAD_CPUTIME_ID, +#endif + }; + + for(clockid_t clock : clock_types) + { + struct timespec ts; + if(::clock_gettime(clock, &ts) == 0) + { + return (static_cast<uint64_t>(ts.tv_sec) * 1000000000) + static_cast<uint64_t>(ts.tv_nsec); + } + } +#endif + + // Plain C++11 fallback + auto now = std::chrono::high_resolution_clock::now().time_since_epoch(); + return std::chrono::duration_cast<std::chrono::nanoseconds>(now).count(); + } + +uint64_t OS::get_system_timestamp_ns() + { +#if defined(BOTAN_TARGET_OS_HAS_CLOCK_GETTIME) + struct timespec ts; + if(::clock_gettime(CLOCK_REALTIME, &ts) == 0) + { + return (static_cast<uint64_t>(ts.tv_sec) * 1000000000) + static_cast<uint64_t>(ts.tv_nsec); + } +#endif + + auto now = std::chrono::system_clock::now().time_since_epoch(); + return std::chrono::duration_cast<std::chrono::nanoseconds>(now).count(); + } + +size_t OS::system_page_size() + { + const size_t default_page_size = 4096; + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + long p = ::sysconf(_SC_PAGESIZE); + if(p > 1) + return static_cast<size_t>(p); + else + return default_page_size; +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + BOTAN_UNUSED(default_page_size); + SYSTEM_INFO sys_info; + ::GetSystemInfo(&sys_info); + return sys_info.dwPageSize; +#else + return default_page_size; +#endif + } + +size_t OS::get_memory_locking_limit() + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) && defined(RLIMIT_MEMLOCK) + /* + * If RLIMIT_MEMLOCK is not defined, likely the OS does not support + * unprivileged mlock calls. + * + * Linux defaults to only 64 KiB of mlockable memory per process + * (too small) but BSDs offer a small fraction of total RAM (more + * than we need). Bound the total mlock size to 512 KiB which is + * enough to run the entire test suite without spilling to non-mlock + * memory (and thus presumably also enough for many useful + * programs), but small enough that we should not cause problems + * even if many processes are mlocking on the same machine. + */ + const size_t user_req = read_env_variable_sz("BOTAN_MLOCK_POOL_SIZE", BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB); + + const size_t mlock_requested = std::min<size_t>(user_req, BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB); + + if(mlock_requested > 0) + { + struct ::rlimit limits; + + ::getrlimit(RLIMIT_MEMLOCK, &limits); + + if(limits.rlim_cur < limits.rlim_max) + { + limits.rlim_cur = limits.rlim_max; + ::setrlimit(RLIMIT_MEMLOCK, &limits); + ::getrlimit(RLIMIT_MEMLOCK, &limits); + } + + return std::min<size_t>(limits.rlim_cur, mlock_requested * 1024); + } + +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + SIZE_T working_min = 0, working_max = 0; + if(!::GetProcessWorkingSetSize(::GetCurrentProcess(), &working_min, &working_max)) + { + return 0; + } + + // According to Microsoft MSDN: + // The maximum number of pages that a process can lock is equal to the number of pages in its minimum working set minus a small overhead + // In the book "Windows Internals Part 2": the maximum lockable pages are minimum working set size - 8 pages + // But the information in the book seems to be inaccurate/outdated + // I've tested this on Windows 8.1 x64, Windows 10 x64 and Windows 7 x86 + // On all three OS the value is 11 instead of 8 + const size_t overhead = OS::system_page_size() * 11; + if(working_min > overhead) + { + const size_t lockable_bytes = working_min - overhead; + return std::min<size_t>(lockable_bytes, BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB * 1024); + } +#endif + + // Not supported on this platform + return 0; + } + +bool OS::read_env_variable(std::string& value_out, const std::string& name) + { + value_out = ""; + + if(running_in_privileged_state()) + return false; + +#if defined(BOTAN_TARGET_OS_HAS_WIN32) && defined(BOTAN_BUILD_COMPILER_IS_MSVC) + char val[128] = { 0 }; + size_t req_size = 0; + if(getenv_s(&req_size, val, sizeof(val), name.c_str()) == 0) + { + value_out = std::string(val, req_size); + return true; + } +#else + if(const char* val = std::getenv(name.c_str())) + { + value_out = val; + return true; + } +#endif + + return false; + } + +size_t OS::read_env_variable_sz(const std::string& name, size_t def) + { + std::string value; + if(read_env_variable(value, name)) + { + try + { + const size_t val = std::stoul(value, nullptr); + return val; + } + catch(std::exception&) { /* ignore it */ } + } + + return def; + } + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) + +namespace { + +int get_locked_fd() + { +#if defined(BOTAN_TARGET_OS_IS_IOS) || defined(BOTAN_TARGET_OS_IS_MACOS) + // On Darwin, tagging anonymous pages allows vmmap to track these. + // Allowed from 240 to 255 for userland applications + static constexpr int default_locked_fd = 255; + int locked_fd = default_locked_fd; + + if(size_t locked_fdl = OS::read_env_variable_sz("BOTAN_LOCKED_FD", default_locked_fd)) + { + if(locked_fdl < 240 || locked_fdl > 255) + { + locked_fdl = default_locked_fd; + } + locked_fd = static_cast<int>(locked_fdl); + } + return VM_MAKE_TAG(locked_fd); +#else + return -1; +#endif + } + +} + +#endif + +std::vector<void*> OS::allocate_locked_pages(size_t count) + { + std::vector<void*> result; + +#if (defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)) || defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + + result.reserve(count); + + const size_t page_size = OS::system_page_size(); + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) + static const int locked_fd = get_locked_fd(); +#endif + + for(size_t i = 0; i != count; ++i) + { + void* ptr = nullptr; + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) + +#if !defined(MAP_ANONYMOUS) + #define MAP_ANONYMOUS MAP_ANON +#endif + +#if !defined(MAP_NOCORE) +#if defined(MAP_CONCEAL) + #define MAP_NOCORE MAP_CONCEAL +#else + #define MAP_NOCORE 0 +#endif +#endif + +#if !defined(PROT_MAX) + #define PROT_MAX(p) 0 +#endif + const int pflags = PROT_READ | PROT_WRITE; + + ptr = ::mmap(nullptr, 3*page_size, + pflags | PROT_MAX(pflags), + MAP_ANONYMOUS | MAP_PRIVATE | MAP_NOCORE, + /*fd=*/locked_fd, /*offset=*/0); + + if(ptr == MAP_FAILED) + { + continue; + } + + // lock the data page + if(::mlock(static_cast<uint8_t*>(ptr) + page_size, page_size) != 0) + { + ::munmap(ptr, 3*page_size); + continue; + } + +#if defined(MADV_DONTDUMP) + // we ignore errors here, as DONTDUMP is just a bonus + ::madvise(static_cast<uint8_t*>(ptr) + page_size, page_size, MADV_DONTDUMP); +#endif + +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + ptr = ::VirtualAlloc(nullptr, 3*page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE); + + if(ptr == nullptr) + continue; + + if(::VirtualLock(static_cast<uint8_t*>(ptr) + page_size, page_size) == 0) + { + ::VirtualFree(ptr, 0, MEM_RELEASE); + continue; + } +#endif + + std::memset(ptr, 0, 3*page_size); // zero data page and both guard pages + + // Make guard page preceeding the data page + page_prohibit_access(static_cast<uint8_t*>(ptr)); + // Make guard page following the data page + page_prohibit_access(static_cast<uint8_t*>(ptr) + 2*page_size); + + result.push_back(static_cast<uint8_t*>(ptr) + page_size); + } +#else + BOTAN_UNUSED(count); +#endif + + return result; + } + +void OS::page_allow_access(void* page) + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + const size_t page_size = OS::system_page_size(); + ::mprotect(page, page_size, PROT_READ | PROT_WRITE); +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + const size_t page_size = OS::system_page_size(); + DWORD old_perms = 0; + ::VirtualProtect(page, page_size, PAGE_READWRITE, &old_perms); + BOTAN_UNUSED(old_perms); +#else + BOTAN_UNUSED(page); +#endif + } + +void OS::page_prohibit_access(void* page) + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + const size_t page_size = OS::system_page_size(); + ::mprotect(page, page_size, PROT_NONE); +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + const size_t page_size = OS::system_page_size(); + DWORD old_perms = 0; + ::VirtualProtect(page, page_size, PAGE_NOACCESS, &old_perms); + BOTAN_UNUSED(old_perms); +#else + BOTAN_UNUSED(page); +#endif + } + +void OS::free_locked_pages(const std::vector<void*>& pages) + { + const size_t page_size = OS::system_page_size(); + + for(size_t i = 0; i != pages.size(); ++i) + { + void* ptr = pages[i]; + + secure_scrub_memory(ptr, page_size); + + // ptr points to the data page, guard pages are before and after + page_allow_access(static_cast<uint8_t*>(ptr) - page_size); + page_allow_access(static_cast<uint8_t*>(ptr) + page_size); + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) + ::munlock(ptr, page_size); + ::munmap(static_cast<uint8_t*>(ptr) - page_size, 3*page_size); +#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK) + ::VirtualUnlock(ptr, page_size); + ::VirtualFree(static_cast<uint8_t*>(ptr) - page_size, 0, MEM_RELEASE); +#endif + } + } + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN) + +namespace { + +static ::sigjmp_buf g_sigill_jmp_buf; + +void botan_sigill_handler(int) + { + siglongjmp(g_sigill_jmp_buf, /*non-zero return value*/1); + } + +} + +#endif + +int OS::run_cpu_instruction_probe(std::function<int ()> probe_fn) + { + volatile int probe_result = -3; + +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN) + struct sigaction old_sigaction; + struct sigaction sigaction; + + sigaction.sa_handler = botan_sigill_handler; + sigemptyset(&sigaction.sa_mask); + sigaction.sa_flags = 0; + + int rc = ::sigaction(SIGILL, &sigaction, &old_sigaction); + + if(rc != 0) + throw System_Error("run_cpu_instruction_probe sigaction failed", errno); + + rc = sigsetjmp(g_sigill_jmp_buf, /*save sigs*/1); + + if(rc == 0) + { + // first call to sigsetjmp + probe_result = probe_fn(); + } + else if(rc == 1) + { + // non-local return from siglongjmp in signal handler: return error + probe_result = -1; + } + + // Restore old SIGILL handler, if any + rc = ::sigaction(SIGILL, &old_sigaction, nullptr); + if(rc != 0) + throw System_Error("run_cpu_instruction_probe sigaction restore failed", errno); + +#else + BOTAN_UNUSED(probe_fn); +#endif + + return probe_result; + } + +std::unique_ptr<OS::Echo_Suppression> OS::suppress_echo_on_terminal() + { +#if defined(BOTAN_TARGET_OS_HAS_POSIX1) + class POSIX_Echo_Suppression : public Echo_Suppression + { + public: + POSIX_Echo_Suppression() + { + m_stdin_fd = fileno(stdin); + if(::tcgetattr(m_stdin_fd, &m_old_termios) != 0) + throw System_Error("Getting terminal status failed", errno); + + struct termios noecho_flags = m_old_termios; + noecho_flags.c_lflag &= ~ECHO; + noecho_flags.c_lflag |= ECHONL; + + if(::tcsetattr(m_stdin_fd, TCSANOW, &noecho_flags) != 0) + throw System_Error("Clearing terminal echo bit failed", errno); + } + + void reenable_echo() override + { + if(m_stdin_fd > 0) + { + if(::tcsetattr(m_stdin_fd, TCSANOW, &m_old_termios) != 0) + throw System_Error("Restoring terminal echo bit failed", errno); + m_stdin_fd = -1; + } + } + + ~POSIX_Echo_Suppression() + { + try + { + reenable_echo(); + } + catch(...) + { + } + } + + private: + int m_stdin_fd; + struct termios m_old_termios; + }; + + return std::unique_ptr<Echo_Suppression>(new POSIX_Echo_Suppression); + +#elif defined(BOTAN_TARGET_OS_HAS_WIN32) + + class Win32_Echo_Suppression : public Echo_Suppression + { + public: + Win32_Echo_Suppression() + { + m_input_handle = ::GetStdHandle(STD_INPUT_HANDLE); + if(::GetConsoleMode(m_input_handle, &m_console_state) == 0) + throw System_Error("Getting console mode failed", ::GetLastError()); + + DWORD new_mode = ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT; + if(::SetConsoleMode(m_input_handle, new_mode) == 0) + throw System_Error("Setting console mode failed", ::GetLastError()); + } + + void reenable_echo() override + { + if(m_input_handle != INVALID_HANDLE_VALUE) + { + if(::SetConsoleMode(m_input_handle, m_console_state) == 0) + throw System_Error("Setting console mode failed", ::GetLastError()); + m_input_handle = INVALID_HANDLE_VALUE; + } + } + + ~Win32_Echo_Suppression() + { + try + { + reenable_echo(); + } + catch(...) + { + } + } + + private: + HANDLE m_input_handle; + DWORD m_console_state; + }; + + return std::unique_ptr<Echo_Suppression>(new Win32_Echo_Suppression); + +#else + + // Not supported on this platform, return null + return std::unique_ptr<Echo_Suppression>(); +#endif + } + +} |