| 1 | // |
|---|
| 2 | // Copyright (c) 2018 Andrey Semashev |
|---|
| 3 | // |
|---|
| 4 | // Distributed under the Boost Software License, Version 1.0. |
|---|
| 5 | // (See accompanying file LICENSE_1_0.txt or copy at |
|---|
| 6 | // https://www.boost.org/LICENSE_1_0.txt) |
|---|
| 7 | // |
|---|
| 8 | // getrandom() capable platforms |
|---|
| 9 | // |
|---|
| 10 | |
|---|
| 11 | #include <boost/config.hpp> |
|---|
| 12 | #include <boost/throw_exception.hpp> |
|---|
| 13 | #include <boost/predef/library/c/gnu.h> |
|---|
| 14 | #include <cerrno> |
|---|
| 15 | #include <cstddef> |
|---|
| 16 | |
|---|
| 17 | #if !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM) && !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_DISABLE_LIBC_WRAPPER) |
|---|
| 18 | #if BOOST_LIB_C_GNU >= BOOST_VERSION_NUMBER(2, 25, 0) |
|---|
| 19 | #define BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER |
|---|
| 20 | #elif defined(__has_include) |
|---|
| 21 | #if __has_include(<sys/random.h>) |
|---|
| 22 | #define BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER |
|---|
| 23 | #endif |
|---|
| 24 | #endif |
|---|
| 25 | #endif // !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM) && !defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_DISABLE_LIBC_WRAPPER) |
|---|
| 26 | |
|---|
| 27 | #if defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER) |
|---|
| 28 | #include <sys/random.h> |
|---|
| 29 | #else |
|---|
| 30 | #include <stddef.h> // ssize_t |
|---|
| 31 | #endif |
|---|
| 32 | |
|---|
| 33 | namespace boost { |
|---|
| 34 | namespace uuids { |
|---|
| 35 | namespace detail { |
|---|
| 36 | |
|---|
| 37 | class random_provider_base |
|---|
| 38 | { |
|---|
| 39 | public: |
|---|
| 40 | //! Obtain entropy and place it into a memory location |
|---|
| 41 | //! \param[in] buf the location to write entropy |
|---|
| 42 | //! \param[in] siz the number of bytes to acquire |
|---|
| 43 | void get_random_bytes(void *buf, std::size_t siz) |
|---|
| 44 | { |
|---|
| 45 | std::size_t offset = 0; |
|---|
| 46 | while (offset < siz) |
|---|
| 47 | { |
|---|
| 48 | ssize_t sz = get_random(buf: static_cast< char* >(buf) + offset, size: siz - offset, flags: 0u); |
|---|
| 49 | |
|---|
| 50 | if (BOOST_UNLIKELY(sz < 0)) |
|---|
| 51 | { |
|---|
| 52 | int err = errno; |
|---|
| 53 | if (err == EINTR) |
|---|
| 54 | continue; |
|---|
| 55 | BOOST_THROW_EXCEPTION(entropy_error(err, "getrandom" )); |
|---|
| 56 | } |
|---|
| 57 | |
|---|
| 58 | offset += sz; |
|---|
| 59 | } |
|---|
| 60 | } |
|---|
| 61 | |
|---|
| 62 | private: |
|---|
| 63 | static ssize_t get_random(void *buf, std::size_t size, unsigned int flags) |
|---|
| 64 | { |
|---|
| 65 | #if defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM) |
|---|
| 66 | return BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_IMPL_GETRANDOM(buf, size, flags); |
|---|
| 67 | #elif defined(BOOST_UUID_RANDOM_PROVIDER_GETRANDOM_HAS_LIBC_WRAPPER) |
|---|
| 68 | return ::getrandom(buffer: buf, length: size, flags: flags); |
|---|
| 69 | #else |
|---|
| 70 | return ::syscall(SYS_getrandom, buf, size, flags); |
|---|
| 71 | #endif |
|---|
| 72 | } |
|---|
| 73 | }; |
|---|
| 74 | |
|---|
| 75 | } // detail |
|---|
| 76 | } // uuids |
|---|
| 77 | } // boost |
|---|
| 78 | |
|---|
