Botan::OS Namespace Reference

Classes
class	Echo_Suppression
class	Socket
class	SocketUDP

Functions
std::vector< void * >	allocate_locked_pages (size_t count)
void	free_locked_pages (const std::vector< void * > &pages)
unsigned long	get_auxval (unsigned long id)
size_t BOTAN_TEST_API	get_cpu_available ()
uint64_t BOTAN_TEST_API	get_cpu_cycle_counter ()
size_t BOTAN_TEST_API	get_cpu_total ()
uint64_t BOTAN_TEST_API	get_high_resolution_clock ()
size_t	get_memory_locking_limit ()
uint32_t BOTAN_TEST_API	get_process_id ()
uint64_t BOTAN_TEST_API	get_system_timestamp_ns ()
std::unique_ptr< Socket > BOTAN_TEST_API	open_socket (const std::string &hostname, const std::string &service, std::chrono::milliseconds timeout)
std::unique_ptr< SocketUDP > BOTAN_TEST_API	open_socket_udp (const std::string &hostname, const std::string &service, std::chrono::microseconds timeout)
std::unique_ptr< SocketUDP > BOTAN_TEST_API	open_socket_udp (const std::string &uri, std::chrono::microseconds timeout)
void	page_allow_access (void *page)
void	page_prohibit_access (void *page)
bool	read_env_variable (std::string &value_out, const std::string &var_name)
size_t	read_env_variable_sz (const std::string &var_name, size_t def_value=0)
int BOTAN_TEST_API	run_cpu_instruction_probe (std::function< int()> probe_fn)
bool	running_in_privileged_state ()
std::unique_ptr< Echo_Suppression > BOTAN_UNSTABLE_API	suppress_echo_on_terminal ()
size_t	system_page_size ()

Function Documentation

std::vector< void * > Botan::OS::allocate_locked_pages

(

size_t

count

)

Request count pages of RAM which are locked into memory using mlock, VirtualLock, or some similar OS specific API. Free it with free_locked_pages.

Returns an empty list on failure. This function is allowed to return fewer than count pages.

The contents of the allocated pages are undefined.

Each page is preceded by and followed by a page which is marked as noaccess, such that accessing it will cause a crash. This turns out of bound reads/writes into crash events.

Parameters

count

requested number of locked pages

Definition at line 459 of file os_utils.cpp.

References page_prohibit_access(), and 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

   std::vector<void*> result;
   result.reserve(count);

   const size_t page_size = OS::system_page_size();

   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, 2*page_size,
                   pflags | PROT_MAX(pflags),
                   MAP_ANONYMOUS | MAP_PRIVATE | MAP_NOCORE,
                   /*fd=*/locked_fd, /*offset=*/0);

      if(ptr == MAP_FAILED)
         {
         continue;
         }

      // failed to lock
      if(::mlock(ptr, page_size) != 0)
         {
         ::munmap(ptr, 2*page_size);
         continue;
         }

#if defined(MADV_DONTDUMP)
      // we ignore errors here, as DONTDUMP is just a bonus
      ::madvise(ptr, page_size, MADV_DONTDUMP);
#endif

#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
      ptr = ::VirtualAlloc(nullptr, 2*page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);

      if(ptr == nullptr)
         continue;

      if(::VirtualLock(ptr, page_size) == 0)
         {
         ::VirtualFree(ptr, 0, MEM_RELEASE);
         continue;
         }
#endif

      std::memset(ptr, 0, 2*page_size); // zero both data and guard pages

      // Make guard page following the data page
      page_prohibit_access(static_cast<uint8_t*>(ptr) + page_size);

      result.push_back(ptr);
      }

   return result;
   }

void Botan::OS::free_locked_pages

(

const std::vector< void * > &

pages

)

Free memory allocated by allocate_locked_pages

Parameters

pages

a list of pages returned by allocate_locked_pages

Definition at line 563 of file os_utils.cpp.

References page_allow_access(), Botan::secure_scrub_memory(), and system_page_size().

   {
   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 page follows
      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(ptr, 2*page_size);
#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
      ::VirtualUnlock(ptr, page_size);
      ::VirtualFree(ptr, 0, MEM_RELEASE);
#endif
      }
   }

unsigned long Botan::OS::get_auxval

(

unsigned long

id

)

Return the ELF auxiliary vector cooresponding to the given ID. This only makes sense on Unix-like systems and is currently only supported on Linux, Android, and FreeBSD.

Returns zero if not supported on the current system or if the id provided is not known.

Definition at line 109 of file os_utils.cpp.

References BOTAN_UNUSED.

Referenced by running_in_privileged_state().

   {
#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
   }

size_t Botan::OS::get_cpu_available

(

)

Definition at line 230 of file os_utils.cpp.

References get_cpu_total().

Referenced by Botan::Thread_Pool::Thread_Pool().

   {
#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 Botan::OS::get_cpu_cycle_counter

(

)

Returns

CPU processor clock, if available

On Windows, calls QueryPerformanceCounter.

Under GCC or Clang on supported platforms the hardware cycle counter is queried. Currently supported processors are x86, PPC, Alpha, SPARC, IA-64, S/390x, and HP-PA. If no CPU cycle counter is available on this system, returns zero.

Definition at line 154 of file os_utils.cpp.

Referenced by get_high_resolution_clock(), Botan::Timer::start(), and Botan::Timer::stop().

   {
   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 Botan::OS::get_cpu_total

(

)

Definition at line 215 of file os_utils.cpp.

Referenced by get_cpu_available().

   {
#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
   }

uint64_t Botan::OS::get_high_resolution_clock

(

)

Definition at line 241 of file os_utils.cpp.

References get_cpu_cycle_counter().

Referenced by Botan::Stateful_RNG::randomize_with_ts_input(), and Botan::RandomNumberGenerator::randomize_with_ts_input().

   {
   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();
   }

size_t Botan::OS::get_memory_locking_limit

(

)

Returns

maximum amount of memory (in bytes) Botan could/should hyptothetically allocate for the memory poool. Reads environment variable "BOTAN_MLOCK_POOL_SIZE", set to "0" to disable pool.

Definition at line 327 of file os_utils.cpp.

References read_env_variable_sz(), and system_page_size().

   {
#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;
   }

uint32_t Botan::OS::get_process_id

(

)

Returns

process ID assigned by the operating system. On Unix and Windows systems, this always returns a result On IncludeOS it returns 0 since there is no process ID to speak of in a unikernel.

Definition at line 96 of file os_utils.cpp.

Referenced by Botan::Stateful_RNG::reseed_check().

   {
#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)
   return 0; // truly no meaningful value
#else
   #error "Missing get_process_id"
#endif
   }

uint64_t Botan::OS::get_system_timestamp_ns

(

)

Returns

system clock (reflecting wall clock) with best resolution available, normalized to nanoseconds resolution.

Definition at line 293 of file os_utils.cpp.

Referenced by Botan::Stateful_RNG::randomize_with_ts_input(), Botan::RandomNumberGenerator::randomize_with_ts_input(), Botan::Timer::start(), and Botan::Timer::stop().

   {
#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::unique_ptr< OS::Socket > Botan::OS::open_socket	(	const std::string &	hostname,
		const std::string &	service,
		std::chrono::milliseconds	timeout
	)

Open up a socket. Will throw on error. Returns null if sockets are not available on this platform.

Definition at line 352 of file socket.cpp.

References BOTAN_UNUSED.

   {
#if defined(BOTAN_HAS_BOOST_ASIO)
   return std::unique_ptr<OS::Socket>(new Asio_Socket(hostname, service, timeout));

#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS) || defined(BOTAN_TARGET_OS_HAS_WINSOCK2)
   return std::unique_ptr<OS::Socket>(new BSD_Socket(hostname, service, timeout));

#else
   BOTAN_UNUSED(hostname);
   BOTAN_UNUSED(service);
   BOTAN_UNUSED(timeout);
   // No sockets for you
   return std::unique_ptr<Socket>();
#endif
   }

std::unique_ptr< OS::SocketUDP > Botan::OS::open_socket_udp	(	const std::string &	hostname,
		const std::string &	service,
		std::chrono::microseconds	timeout
	)

Open up a socket. Will throw on error. Returns null if sockets are not available on this platform.

Definition at line 316 of file socket_udp.cpp.

References BOTAN_UNUSED.

Referenced by Botan::Roughtime::online_request(), and open_socket_udp().

   {
#if defined(BOTAN_HAS_BOOST_ASIO)
   return std::unique_ptr<OS::SocketUDP>(new Asio_SocketUDP(hostname, service, timeout));
#elif defined(BOTAN_TARGET_OS_HAS_SOCKETS) || defined(BOTAN_TARGET_OS_HAS_WINSOCK2)
   return std::unique_ptr<OS::SocketUDP>(new BSD_SocketUDP(hostname, service, timeout));
#else
   BOTAN_UNUSED(hostname);
   BOTAN_UNUSED(service);
   BOTAN_UNUSED(timeout);
   return std::unique_ptr<OS::SocketUDP>();
#endif
   }

std::unique_ptr< OS::SocketUDP > Botan::OS::open_socket_udp	(	const std::string &	uri,
		std::chrono::microseconds	timeout
	)

Open up a socket. Will throw on error. Returns null if sockets are not available on this platform.

Definition at line 333 of file socket_udp.cpp.

References Botan::URI::fromAny(), open_socket_udp(), and Botan::ASN1::to_string().

   {
   const auto uri = URI::fromAny(uri_string);
   if(uri.port == 0)
      { throw Invalid_Argument("UDP port not specified"); }
   return open_socket_udp(uri.host, std::to_string(uri.port), timeout);
   }

void Botan::OS::page_allow_access

(

void *

page

)

Set the MMU to allow R/W access to this page

Definition at line 539 of file os_utils.cpp.

References BOTAN_UNUSED, and system_page_size().

Referenced by Botan::Memory_Pool::allocate(), free_locked_pages(), Botan::Sodium::sodium_mprotect_readwrite(), and Botan::Memory_Pool::~Memory_Pool().

   {
   const size_t page_size = OS::system_page_size();
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
   ::mprotect(page, page_size, PROT_READ | PROT_WRITE);
#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
   DWORD old_perms = 0;
   ::VirtualProtect(page, page_size, PAGE_READWRITE, &old_perms);
   BOTAN_UNUSED(old_perms);
#endif
   }

void Botan::OS::page_prohibit_access

(

void *

page

)

Set the MMU to prohibit access to this page

Definition at line 551 of file os_utils.cpp.

References BOTAN_UNUSED, and system_page_size().

Referenced by allocate_locked_pages(), Botan::Memory_Pool::deallocate(), Botan::Memory_Pool::Memory_Pool(), and Botan::Sodium::sodium_mprotect_noaccess().

   {
   const size_t page_size = OS::system_page_size();
#if defined(BOTAN_TARGET_OS_HAS_POSIX1)
   ::mprotect(page, page_size, PROT_NONE);
#elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
   DWORD old_perms = 0;
   ::VirtualProtect(page, page_size, PAGE_NOACCESS, &old_perms);
   BOTAN_UNUSED(old_perms);
#endif
   }

bool Botan::OS::read_env_variable	(	std::string &	value_out,
		const std::string &	var_name
	)

Read the value of an environment variable, setting it to value_out if it exists. Returns false and sets value_out to empty string if no such variable is set. If the process seems to be running in a privileged state (such as setuid) then always returns false and does not examine the environment.

Definition at line 387 of file os_utils.cpp.

References running_in_privileged_state().

Referenced by Botan_FFI::ffi_error_exception_thrown(), and read_env_variable_sz().

   {
   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 Botan::OS::read_env_variable_sz	(	const std::string &	var_name,
		size_t	def_value = 0
	)

Read the value of an environment variable and convert it to an integer. If not set or conversion fails, returns the default value.

If the process seems to be running in a privileged state (such as setuid) then always returns nullptr, similiar to glibc's secure_getenv.

Definition at line 413 of file os_utils.cpp.

References read_env_variable().

Referenced by get_memory_locking_limit(), and Botan::Thread_Pool::global_instance().

   {
   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;
   }

int Botan::OS::run_cpu_instruction_probe

(

std::function< int()>

probe_fn

)

Run a probe instruction to test for support for a CPU instruction. Runs in system-specific env that catches illegal instructions; this function always fails if the OS doesn't provide this. Returns value of probe_fn, if it could run. If error occurs, returns negative number. This allows probe_fn to indicate errors of its own, if it wants. For example the instruction might not only be only available on some CPUs, but also buggy on some subset of these - the probe function can test to make sure the instruction works properly before indicating that the instruction is available.

Warning

on Unix systems uses signal handling in a way that is not thread safe. It should only be called in a single-threaded context (ie, at static init time).

If probe_fn throws an exception the result is undefined.

Return codes: -1 illegal instruction detected

Definition at line 601 of file os_utils.cpp.

References BOTAN_UNUSED.

   {
   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;
   }

bool Botan::OS::running_in_privileged_state

(

)

Test if we are currently running with elevated permissions eg setuid, setgid, or with POSIX caps set.

Definition at line 143 of file os_utils.cpp.

References get_auxval().

Referenced by Botan::Entropy_Source::create(), and read_env_variable().

   {
#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
   }

std::unique_ptr< OS::Echo_Suppression > Botan::OS::suppress_echo_on_terminal

(

)

Suppress echo on the terminal Returns null if this operation is not supported on the current system.

Definition at line 643 of file os_utils.cpp.

   {
#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
   }

size_t Botan::OS::system_page_size

(

)

Return the size of a memory page, if that can be derived on the current system. Otherwise returns some default value (eg 4096)

Definition at line 307 of file os_utils.cpp.

References BOTAN_UNUSED.

Referenced by allocate_locked_pages(), free_locked_pages(), get_memory_locking_limit(), page_allow_access(), and page_prohibit_access().

   {
   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
   }