/*

* 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/exceptn.h>

#include <botan/mem_ops.h>

#include <botan/internal/cpuid.h>

#include <algorithm>

#include <chrono>

#include <cstdlib>

#include <iomanip>

#include <sstream>

#if defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO)

   #include <string.h>

#endif

#if defined(BOTAN_TARGET_OS_HAS_POSIX1)

   #include <errno.h>

   #include <pthread.h>

   #include <setjmp.h>

   #include <signal.h>

   #include <stdlib.h>

   #include <sys/mman.h>

   #include <sys/resource.h>

   #include <sys/types.h>

   #include <termios.h>

   #include <unistd.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_AUXINFO)

   #include <dlfcn.h>

   #include <elf.h>

#endif

#if defined(BOTAN_TARGET_OS_HAS_WIN32)

   #define NOMINMAX 1

   #define _WINSOCKAPI_  // stop windows.h including winsock.h

   #include <windows.h>

   #if defined(BOTAN_BUILD_COMPILER_IS_MSVC)

      #include <libloaderapi.h>

      #include <stringapiset.h>

   #endif

#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>

   #include <sys/sysctl.h>

   #include <sys/types.h>

#endif

#if defined(BOTAN_TARGET_OS_HAS_PRCTL)

   #include <sys/prctl.h>

#endif

#if defined(BOTAN_TARGET_OS_IS_FREEBSD) || defined(BOTAN_TARGET_OS_IS_OPENBSD) || defined(BOTAN_TARGET_OS_IS_DRAGONFLY)

   #include <pthread_np.h>

#endif

#if defined(BOTAN_TARGET_OS_IS_HAIKU)

   #include <kernel/OS.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_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(static_cast<int>(id), &auxinfo, sizeof(auxinfo));

   return auxinfo;

#elif defined(BOTAN_TARGET_OS_HAS_AUXINFO)

   for(const AuxInfo* auxinfo = static_cast<AuxInfo*>(::_dlauxinfo()); auxinfo != AT_NULL; ++auxinfo) {

      if(id == auxinfo->a_type)

         return auxinfo->a_v;

   }

   return 0;

#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_available() {

#if defined(BOTAN_TARGET_OS_HAS_POSIX1)

   #if defined(_SC_NPROCESSORS_ONLN)

   const long cpu_online = ::sysconf(_SC_NPROCESSORS_ONLN);

   if(cpu_online > 0) {

      return static_cast<size_t>(cpu_online);

   }

   #endif

   #if defined(_SC_NPROCESSORS_CONF)

   const long cpu_conf = ::sysconf(_SC_NPROCESSORS_CONF);

   if(cpu_conf > 0) {

      return static_cast<size_t>(cpu_conf);

   }

   #endif

#endif

#if defined(BOTAN_TARGET_OS_HAS_THREADS)

   // hardware_concurrency is allowed to return 0 if the value is not

   // well defined or not computable.

   const size_t hw_concur = std::thread::hardware_concurrency();

   if(hw_concur > 0) {

      return hw_concur;

   }

#endif

   return 1;

}

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();

}

std::string OS::format_time(time_t time, const std::string& format) {

   std::tm tm;

#if defined(BOTAN_TARGET_OS_HAS_WIN32)

   localtime_s(&tm, &time);

#elif defined(BOTAN_TARGET_OS_HAS_POSIX1)

   localtime_r(&time, &tm);

#else

   if(auto tmp = std::localtime(&time)) {

      tm = *tmp;

   } else {

      throw Encoding_Error("Could not convert time_t to localtime");

   }

#endif

   std::ostringstream oss;

   oss << std::put_time(&tm, format.c_str());

   return oss.str();

}

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() {

   /*

   * 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 max_locked_kb = 512;

   /*

   * If RLIMIT_MEMLOCK is not defined, likely the OS does not support

   * unprivileged mlock calls.

   */

#if defined(RLIMIT_MEMLOCK) && defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)

   const size_t mlock_requested =

      std::min<size_t>(read_env_variable_sz("BOTAN_MLOCK_POOL_SIZE", max_locked_kb), 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)

   const size_t mlock_requested =

      std::min<size_t>(read_env_variable_sz("BOTAN_MLOCK_POOL_SIZE", max_locked_kb), max_locked_kb);

   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, mlock_requested * 1024);

   }

#else

   // Not supported on this platform

   BOTAN_UNUSED(max_locked_kb);

#endif

   return 0;

}

bool OS::read_env_variable(std::string& value_out, std::string_view name_view) {

   value_out = "";

   if(running_in_privileged_state()) {

      return false;

   }

#if defined(BOTAN_TARGET_OS_HAS_WIN32) && defined(BOTAN_BUILD_COMPILER_IS_MSVC)

   const std::string name(name_view);

   char val[128] = {0};

   size_t req_size = 0;

   if(getenv_s(&req_size, val, sizeof(val), name.c_str()) == 0) {

      // Microsoft's implementation always writes a terminating \0,

      // and includes it in the reported length of the environment variable

      // if a value exists.

      if(req_size > 0 && val[req_size - 1] == '\0') {

         value_out = std::string(val);

      } else {

         value_out = std::string(val, req_size);

      }

      return true;

   }

#else

   const std::string name(name_view);

   if(const char* val = std::getenv(name.c_str())) {

      value_out = val;

      return true;

   }

#endif

   return false;

}

size_t OS::read_env_variable_sz(std::string_view name, size_t def) {

   std::string value;

   if(read_env_variable(value, name) && !value.empty()) {

      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

}

}  // namespace

#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)

      int mmap_flags = MAP_PRIVATE;

      #if defined(MAP_ANONYMOUS)

      mmap_flags |= MAP_ANONYMOUS;

      #elif defined(MAP_ANON)

      mmap_flags |= MAP_ANON;

      #endif

      #if defined(MAP_CONCEAL)

      mmap_flags |= MAP_CONCEAL;

      #elif defined(MAP_NOCORE)

      mmap_flags |= MAP_NOCORE;

      #endif

      int mmap_prot = PROT_READ | PROT_WRITE;

      #if defined(PROT_MAX)

      mmap_prot |= PROT_MAX(mmap_prot);

      #endif

      ptr = ::mmap(nullptr,

                   3 * page_size,

                   mmap_prot,

                   mmap_flags,

                   /*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

      // Attempts to name the data page

      page_named(ptr, 3 * page_size);

      // 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

   }

}

void OS::page_named(void* page, size_t size) {

#if defined(BOTAN_TARGET_OS_HAS_PRCTL) && defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)

   static constexpr char name[] = "Botan mlock pool";

   int r = prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, reinterpret_cast<uintptr_t>(page), size, name);

   BOTAN_UNUSED(r);

#else

   BOTAN_UNUSED(page, size);

#endif

}

#if defined(BOTAN_TARGET_OS_HAS_THREADS)

void OS::set_thread_name(std::thread& thread, const std::string& name) {

   #if defined(BOTAN_TARGET_OS_IS_LINUX) || defined(BOTAN_TARGET_OS_IS_FREEBSD) || defined(BOTAN_TARGET_OS_IS_DRAGONFLY)

   static_cast<void>(pthread_setname_np(thread.native_handle(), name.c_str()));

   #elif defined(BOTAN_TARGET_OS_IS_OPENBSD)

   static_cast<void>(pthread_set_name_np(thread.native_handle(), name.c_str()));

   #elif defined(BOTAN_TARGET_OS_IS_NETBSD)

   static_cast<void>(pthread_setname_np(thread.native_handle(), "%s", const_cast<char*>(name.c_str())));

   #elif defined(BOTAN_TARGET_OS_HAS_WIN32) && defined(_LIBCPP_HAS_THREAD_API_PTHREAD)

   static_cast<void>(pthread_setname_np(thread.native_handle(), name.c_str()));

   #elif defined(BOTAN_TARGET_OS_HAS_WIN32) && defined(BOTAN_BUILD_COMPILER_IS_MSVC)

   typedef HRESULT(WINAPI * std_proc)(HANDLE, PCWSTR);

   HMODULE kern = GetModuleHandleA("KernelBase.dll");

   std_proc set_thread_name = reinterpret_cast<std_proc>(GetProcAddress(kern, "SetThreadDescription"));

   if(set_thread_name) {

      std::wstring w;

      auto sz = MultiByteToWideChar(CP_UTF8, 0, name.data(), -1, nullptr, 0);

      if(sz > 0) {

         w.resize(sz);

         if(MultiByteToWideChar(CP_UTF8, 0, name.data(), -1, &w[0], sz) > 0) {

            (void)set_thread_name(thread.native_handle(), w.c_str());

         }

      }

   }

   #elif defined(BOTAN_TARGET_OS_IF_HAIKU)

   auto thread_id = get_pthread_thread_id(thread.native_handle());

   static_cast<void>(rename_thread(thread_id, name.c_str()));

   #else

   // TODO other possible oses ?

   // macOs does not seem to allow to name threads other than the current one.

   BOTAN_UNUSED(thread, name);

   #endif

}

#endif

#if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)

namespace {

// NOLINTNEXTLINE(*-avoid-non-const-global-variables)

::sigjmp_buf g_sigill_jmp_buf;

void botan_sigill_handler(int /*unused*/) {

   siglongjmp(g_sigill_jmp_buf, /*non-zero return value*/ 1);

}

}  // namespace

#endif

int OS::run_cpu_instruction_probe(const 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() override {

            try {

               reenable_echo();

            } catch(...) {}

         }

         POSIX_Echo_Suppression(const POSIX_Echo_Suppression& other) = delete;

         POSIX_Echo_Suppression(POSIX_Echo_Suppression&& other) = delete;

         POSIX_Echo_Suppression& operator=(const POSIX_Echo_Suppression& other) = delete;

         POSIX_Echo_Suppression& operator=(POSIX_Echo_Suppression&& other) = delete;

      private:

         int m_stdin_fd;

         struct termios m_old_termios;

   };

   return std::make_unique<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() override {

            try {

               reenable_echo();

            } catch(...) {}

         }

         Win32_Echo_Suppression(const Win32_Echo_Suppression& other) = delete;

         Win32_Echo_Suppression(Win32_Echo_Suppression&& other) = delete;

         Win32_Echo_Suppression& operator=(const Win32_Echo_Suppression& other) = delete;

         Win32_Echo_Suppression& operator=(Win32_Echo_Suppression&& other) = delete;

      private:

         HANDLE m_input_handle;

         DWORD m_console_state;

   };

   return std::make_unique<Win32_Echo_Suppression>();

#else

   // Not supported on this platform, return null

   return nullptr;

#endif

}

}  // namespace Botan