ceph/src/boost/libs/filesystem/src/unique_path.cpp

   1 //  filesystem unique_path.cpp  --------------------------------------------------------//
   2
   3 //  Copyright Beman Dawes 2010
   4
   5 //  Distributed under the Boost Software License, Version 1.0.
   6 //  See http://www.boost.org/LICENSE_1_0.txt
   7
   8 //  Library home page: http://www.boost.org/libs/filesystem
   9
  10 //--------------------------------------------------------------------------------------//
  11
  12 // define BOOST_FILESYSTEM_SOURCE so that <boost/filesystem/config.hpp> knows
  13 // the library is being built (possibly exporting rather than importing code)
  14 #define BOOST_FILESYSTEM_SOURCE
  15
  16 #ifndef BOOST_SYSTEM_NO_DEPRECATED
  17 # define BOOST_SYSTEM_NO_DEPRECATED
  18 #endif
  19
  20 #include <boost/filesystem/operations.hpp>
  21 #include <cassert>
  22
  23 # ifdef BOOST_POSIX_API
  24 #   include <fcntl.h>
  25 #   ifdef BOOST_HAS_UNISTD_H
  26 #      include <unistd.h>
  27 #   endif
  28 # else // BOOST_WINDOWS_API
  29 #   include <windows.h>
  30 #   include <wincrypt.h>
  31 #   ifdef _MSC_VER
  32 #      pragma comment(lib, "Advapi32.lib")
  33 #   endif
  34 # endif
  35
  36 namespace {
  37
  38 void fail(int err, boost::system::error_code* ec)
  39 {
  40   if (ec == 0)
  41     BOOST_FILESYSTEM_THROW( boost::system::system_error(err,
  42       boost::system::system_category(),
  43       "boost::filesystem::unique_path"));
  44
  45   ec->assign(err, boost::system::system_category());
  46   return;
  47 }
  48
  49 #ifdef BOOST_WINDOWS_API
  50
  51 int acquire_crypt_handle(HCRYPTPROV& handle)
  52 {
  53   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  54     return 0;
  55
  56   int errval = ::GetLastError();
  57   if (errval != NTE_BAD_KEYSET)
  58     return errval;
  59
  60   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET | CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  61     return 0;
  62
  63   errval = ::GetLastError();
  64   // Another thread could have attempted to create the keyset at the same time.
  65   if (errval != NTE_EXISTS)
  66     return errval;
  67
  68   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  69     return 0;
  70
  71   return ::GetLastError();
  72 }
  73
  74 #endif
  75
  76 void system_crypt_random(void* buf, std::size_t len, boost::system::error_code* ec)
  77 {
  78 # ifdef BOOST_POSIX_API
  79
  80   int file = open("/dev/urandom", O_RDONLY);
  81   if (file == -1)
  82   {
  83     file = open("/dev/random", O_RDONLY);
  84     if (file == -1)
  85     {
  86       fail(errno, ec);
  87       return;
  88     }
  89   }
  90
  91   size_t bytes_read = 0;
  92   while (bytes_read < len)
  93   {
  94     ssize_t n = read(file, buf, len - bytes_read);
  95     if (n == -1)
  96     {
  97       close(file);
  98       fail(errno, ec);
  99       return;
 100     }
 101     bytes_read += n;
 102     buf = static_cast<char*>(buf) + n;
 103   }
 104
 105   close(file);
 106
 107 # else // BOOST_WINDOWS_API
 108
 109   HCRYPTPROV handle;
 110   int errval = acquire_crypt_handle(handle);
 111
 112   if (!errval)
 113   {
 114     BOOL gen_ok = ::CryptGenRandom(handle, len, static_cast<unsigned char*>(buf));
 115     if (!gen_ok)
 116       errval = ::GetLastError();
 117     ::CryptReleaseContext(handle, 0);
 118   }
 119
 120   if (!errval) return;
 121
 122   fail(errval, ec);
 123 # endif
 124 }
 125
 126 }  // unnamed namespace
 127
 128 namespace boost { namespace filesystem { namespace detail {
 129
 130 BOOST_FILESYSTEM_DECL
 131 path unique_path(const path& model, system::error_code* ec)
 132 {
 133   std::wstring s (model.wstring());  // std::string ng for MBCS encoded POSIX
 134   const wchar_t hex[] = L"0123456789abcdef";
 135   char ran[] = "123456789abcdef";  // init to avoid clang static analyzer message
 136                                    // see ticket #8954
 137   assert(sizeof(ran) == 16);
 138   const int max_nibbles = 2 * sizeof(ran);   // 4-bits per nibble
 139
 140   int nibbles_used = max_nibbles;
 141   for(std::wstring::size_type i=0; i < s.size(); ++i)
 142   {
 143     if (s[i] == L'%')                        // digit request
 144     {
 145       if (nibbles_used == max_nibbles)
 146       {
 147         system_crypt_random(ran, sizeof(ran), ec);
 148         if (ec != 0 && *ec)
 149           return "";
 150         nibbles_used = 0;
 151       }
 152       int c = ran[nibbles_used/2];
 153       c >>= 4 * (nibbles_used++ & 1);  // if odd, shift right 1 nibble
 154       s[i] = hex[c & 0xf];             // convert to hex digit and replace
 155     }
 156   }
 157
 158   if (ec != 0) ec->clear();
 159
 160   return s;
 161 }
 162
 163 }}}