1 /*
2 * OS and machine specific utility functions
3 * (C) 2015,2016,2017,2018 Jack Lloyd
4 * (C) 2016 Daniel Neus
5 *
6 * Botan is released under the Simplified BSD License (see license.txt)
7 */
8 
9 #include <botan/internal/os_utils.h>
10 #include <botan/cpuid.h>
11 #include <botan/exceptn.h>
12 #include <botan/mem_ops.h>
13 
14 #include <algorithm>
15 #include <chrono>
16 #include <cstdlib>
17 
18 #if defined(BOTAN_TARGET_OS_HAS_THREADS)
19   #include <thread>
20 #endif
21 
22 #if defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO)
23   #include <string.h>
24 #endif
25 
26 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
27   #include <sys/types.h>
28   #include <sys/resource.h>
29   #include <sys/mman.h>
30   #include <signal.h>
31   #include <stdlib.h>
32   #include <setjmp.h>
33   #include <unistd.h>
34   #include <errno.h>
35   #include <termios.h>
36   #undef B0
37 #endif
38 
39 #if defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)
40   #include <emscripten/emscripten.h>
41 #endif
42 
43 #if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL) || defined(BOTAN_TARGET_OS_IS_ANDROID) || \
44   defined(BOTAN_TARGET_OS_HAS_ELF_AUX_INFO)
45   #include <sys/auxv.h>
46 #endif
47 
48 #if defined(BOTAN_TARGET_OS_HAS_WIN32)
49   #define NOMINMAX 1
50   #define _WINSOCKAPI_ // stop windows.h including winsock.h
51   #include <windows.h>
52 #endif
53 
54 #if defined(BOTAN_TARGET_OS_IS_ANDROID)
55   #include <elf.h>
56   extern "C" char **environ;
57 #endif
58 
59 #if defined(BOTAN_TARGET_OS_IS_IOS) || defined(BOTAN_TARGET_OS_IS_MACOS)
60   #include <mach/vm_statistics.h>
61 #endif
62 
63 namespace Botan {
64 
65 // Not defined in OS namespace for historical reasons
secure_scrub_memory(void * ptr,size_t n)66 void secure_scrub_memory(void* ptr, size_t n)
67    {
68 #if defined(BOTAN_TARGET_OS_HAS_RTLSECUREZEROMEMORY)
69    ::RtlSecureZeroMemory(ptr, n);
70 
71 #elif defined(BOTAN_TARGET_OS_HAS_EXPLICIT_BZERO)
72    ::explicit_bzero(ptr, n);
73 
74 #elif defined(BOTAN_TARGET_OS_HAS_EXPLICIT_MEMSET)
75    (void)::explicit_memset(ptr, 0, n);
76 
77 #elif defined(BOTAN_USE_VOLATILE_MEMSET_FOR_ZERO) && (BOTAN_USE_VOLATILE_MEMSET_FOR_ZERO == 1)
78    /*
79    Call memset through a static volatile pointer, which the compiler
80    should not elide. This construct should be safe in conforming
81    compilers, but who knows. I did confirm that on x86-64 GCC 6.1 and
82    Clang 3.8 both create code that saves the memset address in the
83    data segment and unconditionally loads and jumps to that address.
84    */
85    static void* (*const volatile memset_ptr)(void*, int, size_t) = std::memset;
86    (memset_ptr)(ptr, 0, n);
87 #else
88 
89    volatile uint8_t* p = reinterpret_cast<volatile uint8_t*>(ptr);
90 
91    for(size_t i = 0; i != n; ++i)
92       p[i] = 0;
93 #endif
94    }
95 
get_process_id()96 uint32_t OS::get_process_id()
97    {
98 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
99    return ::getpid();
100 #elif defined(BOTAN_TARGET_OS_HAS_WIN32)
101    return ::GetCurrentProcessId();
102 #elif defined(BOTAN_TARGET_OS_IS_INCLUDEOS) || defined(BOTAN_TARGET_OS_IS_LLVM) || defined(BOTAN_TARGET_OS_IS_NONE)
103    return 0; // truly no meaningful value
104 #else
105    #error "Missing get_process_id"
106 #endif
107    }
108 
get_auxval(unsigned long id)109 unsigned long OS::get_auxval(unsigned long id)
110    {
111 #if defined(BOTAN_TARGET_OS_HAS_GETAUXVAL)
112    return ::getauxval(id);
113 #elif defined(BOTAN_TARGET_OS_IS_ANDROID) && defined(BOTAN_TARGET_ARCH_IS_ARM32)
114 
115    if(id == 0)
116       return 0;
117 
118    char **p = environ;
119 
120    while(*p++ != nullptr)
121       ;
122 
123    Elf32_auxv_t *e = reinterpret_cast<Elf32_auxv_t*>(p);
124 
125    while(e != nullptr)
126       {
127       if(e->a_type == id)
128          return e->a_un.a_val;
129       e++;
130       }
131 
132    return 0;
133 #elif defined(BOTAN_TARGET_OS_HAS_ELF_AUX_INFO)
134    unsigned long auxinfo = 0;
135    ::elf_aux_info(id, &auxinfo, sizeof(auxinfo));
136    return auxinfo;
137 #else
138    BOTAN_UNUSED(id);
139    return 0;
140 #endif
141    }
142 
running_in_privileged_state()143 bool OS::running_in_privileged_state()
144    {
145 #if defined(AT_SECURE)
146    return OS::get_auxval(AT_SECURE) != 0;
147 #elif defined(BOTAN_TARGET_OS_HAS_POSIX1)
148    return (::getuid() != ::geteuid()) || (::getgid() != ::getegid());
149 #else
150    return false;
151 #endif
152    }
153 
get_cpu_cycle_counter()154 uint64_t OS::get_cpu_cycle_counter()
155    {
156    uint64_t rtc = 0;
157 
158 #if defined(BOTAN_TARGET_OS_HAS_WIN32)
159    LARGE_INTEGER tv;
160    ::QueryPerformanceCounter(&tv);
161    rtc = tv.QuadPart;
162 
163 #elif defined(BOTAN_USE_GCC_INLINE_ASM)
164 
165 #if defined(BOTAN_TARGET_CPU_IS_X86_FAMILY)
166 
167    if(CPUID::has_rdtsc())
168       {
169       uint32_t rtc_low = 0, rtc_high = 0;
170       asm volatile("rdtsc" : "=d" (rtc_high), "=a" (rtc_low));
171       rtc = (static_cast<uint64_t>(rtc_high) << 32) | rtc_low;
172       }
173 
174 #elif defined(BOTAN_TARGET_ARCH_IS_PPC64)
175 
176    for(;;)
177       {
178       uint32_t rtc_low = 0, rtc_high = 0, rtc_high2 = 0;
179       asm volatile("mftbu %0" : "=r" (rtc_high));
180       asm volatile("mftb %0" : "=r" (rtc_low));
181       asm volatile("mftbu %0" : "=r" (rtc_high2));
182 
183       if(rtc_high == rtc_high2)
184          {
185          rtc = (static_cast<uint64_t>(rtc_high) << 32) | rtc_low;
186          break;
187          }
188       }
189 
190 #elif defined(BOTAN_TARGET_ARCH_IS_ALPHA)
191    asm volatile("rpcc %0" : "=r" (rtc));
192 
193    // OpenBSD does not trap access to the %tick register
194 #elif defined(BOTAN_TARGET_ARCH_IS_SPARC64) && !defined(BOTAN_TARGET_OS_IS_OPENBSD)
195    asm volatile("rd %%tick, %0" : "=r" (rtc));
196 
197 #elif defined(BOTAN_TARGET_ARCH_IS_IA64)
198    asm volatile("mov %0=ar.itc" : "=r" (rtc));
199 
200 #elif defined(BOTAN_TARGET_ARCH_IS_S390X)
201    asm volatile("stck 0(%0)" : : "a" (&rtc) : "memory", "cc");
202 
203 #elif defined(BOTAN_TARGET_ARCH_IS_HPPA)
204    asm volatile("mfctl 16,%0" : "=r" (rtc)); // 64-bit only?
205 
206 #else
207    //#warning "OS::get_cpu_cycle_counter not implemented"
208 #endif
209 
210 #endif
211 
212    return rtc;
213    }
214 
get_cpu_total()215 size_t OS::get_cpu_total()
216    {
217 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(_SC_NPROCESSORS_CONF)
218    const long res = ::sysconf(_SC_NPROCESSORS_CONF);
219    if(res > 0)
220       return static_cast<size_t>(res);
221 #endif
222 
223 #if defined(BOTAN_TARGET_OS_HAS_THREADS)
224    return static_cast<size_t>(std::thread::hardware_concurrency());
225 #else
226    return 1;
227 #endif
228    }
229 
get_cpu_available()230 size_t OS::get_cpu_available()
231    {
232 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(_SC_NPROCESSORS_ONLN)
233    const long res = ::sysconf(_SC_NPROCESSORS_ONLN);
234    if(res > 0)
235       return static_cast<size_t>(res);
236 #endif
237 
238    return OS::get_cpu_total();
239    }
240 
get_high_resolution_clock()241 uint64_t OS::get_high_resolution_clock()
242    {
243    if(uint64_t cpu_clock = OS::get_cpu_cycle_counter())
244       return cpu_clock;
245 
246 #if defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)
247    return emscripten_get_now();
248 #endif
249 
250    /*
251    If we got here either we either don't have an asm instruction
252    above, or (for x86) RDTSC is not available at runtime. Try some
253    clock_gettimes and return the first one that works, or otherwise
254    fall back to std::chrono.
255    */
256 
257 #if defined(BOTAN_TARGET_OS_HAS_CLOCK_GETTIME)
258 
259    // The ordering here is somewhat arbitrary...
260    const clockid_t clock_types[] = {
261 #if defined(CLOCK_MONOTONIC_HR)
262       CLOCK_MONOTONIC_HR,
263 #endif
264 #if defined(CLOCK_MONOTONIC_RAW)
265       CLOCK_MONOTONIC_RAW,
266 #endif
267 #if defined(CLOCK_MONOTONIC)
268       CLOCK_MONOTONIC,
269 #endif
270 #if defined(CLOCK_PROCESS_CPUTIME_ID)
271       CLOCK_PROCESS_CPUTIME_ID,
272 #endif
273 #if defined(CLOCK_THREAD_CPUTIME_ID)
274       CLOCK_THREAD_CPUTIME_ID,
275 #endif
276    };
277 
278    for(clockid_t clock : clock_types)
279       {
280       struct timespec ts;
281       if(::clock_gettime(clock, &ts) == 0)
282          {
283          return (static_cast<uint64_t>(ts.tv_sec) * 1000000000) + static_cast<uint64_t>(ts.tv_nsec);
284          }
285       }
286 #endif
287 
288    // Plain C++11 fallback
289    auto now = std::chrono::high_resolution_clock::now().time_since_epoch();
290    return std::chrono::duration_cast<std::chrono::nanoseconds>(now).count();
291    }
292 
get_system_timestamp_ns()293 uint64_t OS::get_system_timestamp_ns()
294    {
295 #if defined(BOTAN_TARGET_OS_HAS_CLOCK_GETTIME)
296    struct timespec ts;
297    if(::clock_gettime(CLOCK_REALTIME, &ts) == 0)
298       {
299       return (static_cast<uint64_t>(ts.tv_sec) * 1000000000) + static_cast<uint64_t>(ts.tv_nsec);
300       }
301 #endif
302 
303    auto now = std::chrono::system_clock::now().time_since_epoch();
304    return std::chrono::duration_cast<std::chrono::nanoseconds>(now).count();
305    }
306 
system_page_size()307 size_t OS::system_page_size()
308    {
309    const size_t default_page_size = 4096;
310 
311 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
312    long p = ::sysconf(_SC_PAGESIZE);
313    if(p > 1)
314       return static_cast<size_t>(p);
315    else
316       return default_page_size;
317 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
318    BOTAN_UNUSED(default_page_size);
319    SYSTEM_INFO sys_info;
320    ::GetSystemInfo(&sys_info);
321    return sys_info.dwPageSize;
322 #else
323    return default_page_size;
324 #endif
325    }
326 
get_memory_locking_limit()327 size_t OS::get_memory_locking_limit()
328    {
329 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK) && defined(RLIMIT_MEMLOCK)
330    /*
331    * If RLIMIT_MEMLOCK is not defined, likely the OS does not support
332    * unprivileged mlock calls.
333    *
334    * Linux defaults to only 64 KiB of mlockable memory per process
335    * (too small) but BSDs offer a small fraction of total RAM (more
336    * than we need). Bound the total mlock size to 512 KiB which is
337    * enough to run the entire test suite without spilling to non-mlock
338    * memory (and thus presumably also enough for many useful
339    * programs), but small enough that we should not cause problems
340    * even if many processes are mlocking on the same machine.
341    */
342    const size_t user_req = read_env_variable_sz("BOTAN_MLOCK_POOL_SIZE", BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB);
343 
344    const size_t mlock_requested = std::min<size_t>(user_req, BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB);
345 
346    if(mlock_requested > 0)
347       {
348       struct ::rlimit limits;
349 
350       ::getrlimit(RLIMIT_MEMLOCK, &limits);
351 
352       if(limits.rlim_cur < limits.rlim_max)
353          {
354          limits.rlim_cur = limits.rlim_max;
355          ::setrlimit(RLIMIT_MEMLOCK, &limits);
356          ::getrlimit(RLIMIT_MEMLOCK, &limits);
357          }
358 
359       return std::min<size_t>(limits.rlim_cur, mlock_requested * 1024);
360       }
361 
362 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
363    SIZE_T working_min = 0, working_max = 0;
364    if(!::GetProcessWorkingSetSize(::GetCurrentProcess(), &working_min, &working_max))
365       {
366       return 0;
367       }
368 
369    // According to Microsoft MSDN:
370    // 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
371    // In the book "Windows Internals Part 2": the maximum lockable pages are minimum working set size - 8 pages
372    // But the information in the book seems to be inaccurate/outdated
373    // I've tested this on Windows 8.1 x64, Windows 10 x64 and Windows 7 x86
374    // On all three OS the value is 11 instead of 8
375    const size_t overhead = OS::system_page_size() * 11;
376    if(working_min > overhead)
377       {
378       const size_t lockable_bytes = working_min - overhead;
379       return std::min<size_t>(lockable_bytes, BOTAN_MLOCK_ALLOCATOR_MAX_LOCKED_KB * 1024);
380       }
381 #endif
382 
383    // Not supported on this platform
384    return 0;
385    }
386 
read_env_variable(std::string & value_out,const std::string & name)387 bool OS::read_env_variable(std::string& value_out, const std::string& name)
388    {
389    value_out = "";
390 
391    if(running_in_privileged_state())
392       return false;
393 
394 #if defined(BOTAN_TARGET_OS_HAS_WIN32) && defined(BOTAN_BUILD_COMPILER_IS_MSVC)
395    char val[128] = { 0 };
396    size_t req_size = 0;
397    if(getenv_s(&req_size, val, sizeof(val), name.c_str()) == 0)
398       {
399       value_out = std::string(val, req_size);
400       return true;
401       }
402 #else
403    if(const char* val = std::getenv(name.c_str()))
404       {
405       value_out = val;
406       return true;
407       }
408 #endif
409 
410    return false;
411    }
412 
read_env_variable_sz(const std::string & name,size_t def)413 size_t OS::read_env_variable_sz(const std::string& name, size_t def)
414    {
415    std::string value;
416    if(read_env_variable(value, name))
417       {
418       try
419          {
420          const size_t val = std::stoul(value, nullptr);
421          return val;
422          }
423       catch(std::exception&) { /* ignore it */ }
424       }
425 
426    return def;
427    }
428 
429 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
430 
431 namespace {
432 
get_locked_fd()433 int get_locked_fd()
434    {
435 #if defined(BOTAN_TARGET_OS_IS_IOS) || defined(BOTAN_TARGET_OS_IS_MACOS)
436    // On Darwin, tagging anonymous pages allows vmmap to track these.
437    // Allowed from 240 to 255 for userland applications
438    static constexpr int default_locked_fd = 255;
439    int locked_fd = default_locked_fd;
440 
441    if(size_t locked_fdl = OS::read_env_variable_sz("BOTAN_LOCKED_FD", default_locked_fd))
442       {
443       if(locked_fdl < 240 || locked_fdl > 255)
444          {
445          locked_fdl = default_locked_fd;
446          }
447       locked_fd = static_cast<int>(locked_fdl);
448       }
449    return VM_MAKE_TAG(locked_fd);
450 #else
451    return -1;
452 #endif
453    }
454 
455 }
456 
457 #endif
458 
allocate_locked_pages(size_t count)459 std::vector<void*> OS::allocate_locked_pages(size_t count)
460    {
461    std::vector<void*> result;
462 
463 #if (defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)) || defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
464 
465    result.reserve(count);
466 
467    const size_t page_size = OS::system_page_size();
468 
469 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
470    static const int locked_fd = get_locked_fd();
471 #endif
472 
473    for(size_t i = 0; i != count; ++i)
474       {
475       void* ptr = nullptr;
476 
477 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
478 
479 #if !defined(MAP_ANONYMOUS)
480    #define MAP_ANONYMOUS MAP_ANON
481 #endif
482 
483 #if !defined(MAP_NOCORE)
484 #if defined(MAP_CONCEAL)
485    #define MAP_NOCORE MAP_CONCEAL
486 #else
487    #define MAP_NOCORE 0
488 #endif
489 #endif
490 
491 #if !defined(PROT_MAX)
492    #define PROT_MAX(p) 0
493 #endif
494       const int pflags = PROT_READ | PROT_WRITE;
495 
496       ptr = ::mmap(nullptr, 3*page_size,
497                    pflags | PROT_MAX(pflags),
498                    MAP_ANONYMOUS | MAP_PRIVATE | MAP_NOCORE,
499                    /*fd=*/locked_fd, /*offset=*/0);
500 
501       if(ptr == MAP_FAILED)
502          {
503          continue;
504          }
505 
506       // lock the data page
507       if(::mlock(static_cast<uint8_t*>(ptr) + page_size, page_size) != 0)
508          {
509          ::munmap(ptr, 3*page_size);
510          continue;
511          }
512 
513 #if defined(MADV_DONTDUMP)
514       // we ignore errors here, as DONTDUMP is just a bonus
515       ::madvise(static_cast<uint8_t*>(ptr) + page_size, page_size, MADV_DONTDUMP);
516 #endif
517 
518 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
519       ptr = ::VirtualAlloc(nullptr, 3*page_size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
520 
521       if(ptr == nullptr)
522          continue;
523 
524       if(::VirtualLock(static_cast<uint8_t*>(ptr) + page_size, page_size) == 0)
525          {
526          ::VirtualFree(ptr, 0, MEM_RELEASE);
527          continue;
528          }
529 #endif
530 
531       std::memset(ptr, 0, 3*page_size); // zero data page and both guard pages
532 
533       // Make guard page preceeding the data page
534       page_prohibit_access(static_cast<uint8_t*>(ptr));
535       // Make guard page following the data page
536       page_prohibit_access(static_cast<uint8_t*>(ptr) + 2*page_size);
537 
538       result.push_back(static_cast<uint8_t*>(ptr) + page_size);
539       }
540 #else
541    BOTAN_UNUSED(count);
542 #endif
543 
544    return result;
545    }
546 
page_allow_access(void * page)547 void OS::page_allow_access(void* page)
548    {
549 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
550    const size_t page_size = OS::system_page_size();
551    ::mprotect(page, page_size, PROT_READ | PROT_WRITE);
552 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
553    const size_t page_size = OS::system_page_size();
554    DWORD old_perms = 0;
555    ::VirtualProtect(page, page_size, PAGE_READWRITE, &old_perms);
556    BOTAN_UNUSED(old_perms);
557 #else
558    BOTAN_UNUSED(page);
559 #endif
560    }
561 
page_prohibit_access(void * page)562 void OS::page_prohibit_access(void* page)
563    {
564 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
565    const size_t page_size = OS::system_page_size();
566    ::mprotect(page, page_size, PROT_NONE);
567 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
568    const size_t page_size = OS::system_page_size();
569    DWORD old_perms = 0;
570    ::VirtualProtect(page, page_size, PAGE_NOACCESS, &old_perms);
571    BOTAN_UNUSED(old_perms);
572 #else
573    BOTAN_UNUSED(page);
574 #endif
575    }
576 
free_locked_pages(const std::vector<void * > & pages)577 void OS::free_locked_pages(const std::vector<void*>& pages)
578    {
579    const size_t page_size = OS::system_page_size();
580 
581    for(size_t i = 0; i != pages.size(); ++i)
582       {
583       void* ptr = pages[i];
584 
585       secure_scrub_memory(ptr, page_size);
586 
587       // ptr points to the data page, guard pages are before and after
588       page_allow_access(static_cast<uint8_t*>(ptr) - page_size);
589       page_allow_access(static_cast<uint8_t*>(ptr) + page_size);
590 
591 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && defined(BOTAN_TARGET_OS_HAS_POSIX_MLOCK)
592       ::munlock(ptr, page_size);
593       ::munmap(static_cast<uint8_t*>(ptr) - page_size, 3*page_size);
594 #elif defined(BOTAN_TARGET_OS_HAS_VIRTUAL_LOCK)
595       ::VirtualUnlock(ptr, page_size);
596       ::VirtualFree(static_cast<uint8_t*>(ptr) - page_size, 0, MEM_RELEASE);
597 #endif
598       }
599    }
600 
601 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)
602 
603 namespace {
604 
605 static ::sigjmp_buf g_sigill_jmp_buf;
606 
botan_sigill_handler(int)607 void botan_sigill_handler(int)
608    {
609    siglongjmp(g_sigill_jmp_buf, /*non-zero return value*/1);
610    }
611 
612 }
613 
614 #endif
615 
run_cpu_instruction_probe(std::function<int ()> probe_fn)616 int OS::run_cpu_instruction_probe(std::function<int ()> probe_fn)
617    {
618    volatile int probe_result = -3;
619 
620 #if defined(BOTAN_TARGET_OS_HAS_POSIX1) && !defined(BOTAN_TARGET_OS_IS_EMSCRIPTEN)
621    struct sigaction old_sigaction;
622    struct sigaction sigaction;
623 
624    sigaction.sa_handler = botan_sigill_handler;
625    sigemptyset(&sigaction.sa_mask);
626    sigaction.sa_flags = 0;
627 
628    int rc = ::sigaction(SIGILL, &sigaction, &old_sigaction);
629 
630    if(rc != 0)
631       throw System_Error("run_cpu_instruction_probe sigaction failed", errno);
632 
633    rc = sigsetjmp(g_sigill_jmp_buf, /*save sigs*/1);
634 
635    if(rc == 0)
636       {
637       // first call to sigsetjmp
638       probe_result = probe_fn();
639       }
640    else if(rc == 1)
641       {
642       // non-local return from siglongjmp in signal handler: return error
643       probe_result = -1;
644       }
645 
646    // Restore old SIGILL handler, if any
647    rc = ::sigaction(SIGILL, &old_sigaction, nullptr);
648    if(rc != 0)
649       throw System_Error("run_cpu_instruction_probe sigaction restore failed", errno);
650 
651 #else
652    BOTAN_UNUSED(probe_fn);
653 #endif
654 
655    return probe_result;
656    }
657 
suppress_echo_on_terminal()658 std::unique_ptr<OS::Echo_Suppression> OS::suppress_echo_on_terminal()
659    {
660 #if defined(BOTAN_TARGET_OS_HAS_POSIX1)
661    class POSIX_Echo_Suppression : public Echo_Suppression
662       {
663       public:
664          POSIX_Echo_Suppression()
665             {
666             m_stdin_fd = fileno(stdin);
667             if(::tcgetattr(m_stdin_fd, &m_old_termios) != 0)
668                throw System_Error("Getting terminal status failed", errno);
669 
670             struct termios noecho_flags = m_old_termios;
671             noecho_flags.c_lflag &= ~ECHO;
672             noecho_flags.c_lflag |= ECHONL;
673 
674             if(::tcsetattr(m_stdin_fd, TCSANOW, &noecho_flags) != 0)
675                throw System_Error("Clearing terminal echo bit failed", errno);
676             }
677 
678          void reenable_echo() override
679             {
680             if(m_stdin_fd > 0)
681                {
682                if(::tcsetattr(m_stdin_fd, TCSANOW, &m_old_termios) != 0)
683                   throw System_Error("Restoring terminal echo bit failed", errno);
684                m_stdin_fd = -1;
685                }
686             }
687 
688          ~POSIX_Echo_Suppression()
689             {
690             try
691                {
692                reenable_echo();
693                }
694             catch(...)
695                {
696                }
697             }
698 
699       private:
700          int m_stdin_fd;
701          struct termios m_old_termios;
702       };
703 
704    return std::unique_ptr<Echo_Suppression>(new POSIX_Echo_Suppression);
705 
706 #elif defined(BOTAN_TARGET_OS_HAS_WIN32)
707 
708    class Win32_Echo_Suppression : public Echo_Suppression
709       {
710       public:
711          Win32_Echo_Suppression()
712             {
713             m_input_handle = ::GetStdHandle(STD_INPUT_HANDLE);
714             if(::GetConsoleMode(m_input_handle, &m_console_state) == 0)
715                throw System_Error("Getting console mode failed", ::GetLastError());
716 
717             DWORD new_mode = ENABLE_LINE_INPUT | ENABLE_PROCESSED_INPUT;
718             if(::SetConsoleMode(m_input_handle, new_mode) == 0)
719                throw System_Error("Setting console mode failed", ::GetLastError());
720             }
721 
722          void reenable_echo() override
723             {
724             if(m_input_handle != INVALID_HANDLE_VALUE)
725                {
726                if(::SetConsoleMode(m_input_handle, m_console_state) == 0)
727                   throw System_Error("Setting console mode failed", ::GetLastError());
728                m_input_handle = INVALID_HANDLE_VALUE;
729                }
730             }
731 
732          ~Win32_Echo_Suppression()
733             {
734             try
735                {
736                reenable_echo();
737                }
738             catch(...)
739                {
740                }
741             }
742 
743       private:
744          HANDLE m_input_handle;
745          DWORD m_console_state;
746       };
747 
748    return std::unique_ptr<Echo_Suppression>(new Win32_Echo_Suppression);
749 
750 #else
751 
752    // Not supported on this platform, return null
753    return std::unique_ptr<Echo_Suppression>();
754 #endif
755    }
756 
757 }
758