ceph/src/boost/boost/uuid/detail/random_provider_posix.ipp

   1 /* boost uuid/detail/random_provider_posix implementation
   2 *
   3 * Copyright Jens Maurer 2000
   4 * Copyright 2007 Andy Tompkins.
   5 * Copyright Steven Watanabe 2010-2011
   6 * Copyright 2017 James E. King III
   7 *
   8 * Distributed under the Boost Software License, Version 1.0. (See
   9 * accompanying file LICENSE_1_0.txt or copy at
  10 * https://www.boost.org/LICENSE_1_0.txt)
  11 *
  12 * $Id$
  13 */
  14
  15 #include <boost/config.hpp>
  16 #include <boost/core/ignore_unused.hpp>
  17 #include <boost/move/core.hpp>
  18 #include <boost/throw_exception.hpp>
  19 #include <boost/uuid/entropy_error.hpp>
  20 #include <cerrno>
  21 #include <cstddef>
  22 #include <fcntl.h>    // open
  23 #include <sys/stat.h>
  24 #include <sys/types.h>
  25 #if defined(BOOST_HAS_UNISTD_H)
  26 #include <unistd.h>
  27 #endif
  28
  29 #ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE
  30 #define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE ::close
  31 #endif
  32 #ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN
  33 #define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN ::open
  34 #endif
  35 #ifndef BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ
  36 #define BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ ::read
  37 #endif
  38
  39 namespace boost {
  40 namespace uuids {
  41 namespace detail {
  42
  43 class random_provider_base
  44 {
  45     BOOST_MOVABLE_BUT_NOT_COPYABLE(random_provider_base)
  46
  47 public:
  48     random_provider_base()
  49       : fd_(-1)
  50     {
  51         int flags = O_RDONLY;
  52 #if defined(O_CLOEXEC)
  53         flags |= O_CLOEXEC;
  54 #endif
  55         fd_ = BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_OPEN("/dev/urandom", flags);
  56
  57         if (BOOST_UNLIKELY(-1 == fd_))
  58         {
  59             int err = errno;
  60             BOOST_THROW_EXCEPTION(entropy_error(err, "open /dev/urandom"));
  61         }
  62     }
  63
  64     random_provider_base(BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT : fd_(that.fd_)
  65     {
  66         that.fd_ = -1;
  67     }
  68
  69     random_provider_base& operator= (BOOST_RV_REF(random_provider_base) that) BOOST_NOEXCEPT
  70     {
  71         destroy();
  72         fd_ = that.fd_;
  73         that.fd_ = -1;
  74         return *this;
  75     }
  76
  77     ~random_provider_base() BOOST_NOEXCEPT
  78     {
  79         destroy();
  80     }
  81
  82     //! Obtain entropy and place it into a memory location
  83     //! \param[in]  buf  the location to write entropy
  84     //! \param[in]  siz  the number of bytes to acquire
  85     void get_random_bytes(void *buf, std::size_t siz)
  86     {
  87         std::size_t offset = 0;
  88         while (offset < siz)
  89         {
  90             ssize_t sz = BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_READ(
  91                 fd_, static_cast<char *>(buf) + offset, siz - offset);
  92
  93             if (BOOST_UNLIKELY(sz < 0))
  94             {
  95                 int err = errno;
  96                 if (err == EINTR)
  97                     continue;
  98                 BOOST_THROW_EXCEPTION(entropy_error(err, "read"));
  99             }
 100
 101             offset += sz;
 102         }
 103     }
 104
 105 private:
 106     void destroy() BOOST_NOEXCEPT
 107     {
 108         if (fd_ >= 0)
 109         {
 110             boost::ignore_unused(BOOST_UUID_RANDOM_PROVIDER_POSIX_IMPL_CLOSE(fd_));
 111         }
 112     }
 113
 114 private:
 115     int fd_;
 116 };
 117
 118 } // detail
 119 } // uuids
 120 } // boost