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 #ifndef BOOST_SYSTEM_NO_DEPRECATED
  13 # define BOOST_SYSTEM_NO_DEPRECATED
  14 #endif
  15
  16 #include <boost/filesystem/operations.hpp>
  17 #include <cassert>
  18
  19 # ifdef BOOST_POSIX_API
  20 #   include <fcntl.h>
  21 #   ifdef BOOST_HAS_UNISTD_H
  22 #      include <unistd.h>
  23 #   endif
  24 # else // BOOST_WINDOWS_API
  25 #   include <windows.h>
  26 #   include <wincrypt.h>
  27 #   ifdef _MSC_VER
  28 #      pragma comment(lib, "Advapi32.lib")
  29 #   endif
  30 # endif
  31
  32 namespace {
  33
  34 void fail(int err, boost::system::error_code* ec)
  35 {
  36   if (ec == 0)
  37     BOOST_FILESYSTEM_THROW( boost::system::system_error(err,
  38       boost::system::system_category(),
  39       "boost::filesystem::unique_path"));
  40
  41   ec->assign(err, boost::system::system_category());
  42   return;
  43 }
  44
  45 #ifdef BOOST_WINDOWS_API
  46
  47 int acquire_crypt_handle(HCRYPTPROV& handle)
  48 {
  49   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  50     return 0;
  51
  52   int errval = ::GetLastError();
  53   if (errval != NTE_BAD_KEYSET)
  54     return errval;
  55
  56   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_NEWKEYSET | CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  57     return 0;
  58
  59   errval = ::GetLastError();
  60   // Another thread could have attempted to create the keyset at the same time.
  61   if (errval != NTE_EXISTS)
  62     return errval;
  63
  64   if (::CryptAcquireContextW(&handle, 0, 0, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
  65     return 0;
  66
  67   return ::GetLastError();
  68 }
  69
  70 #endif
  71
  72 void system_crypt_random(void* buf, std::size_t len, boost::system::error_code* ec)
  73 {
  74 # ifdef BOOST_POSIX_API
  75
  76   int file = open("/dev/urandom", O_RDONLY);
  77   if (file == -1)
  78   {
  79     file = open("/dev/random", O_RDONLY);
  80     if (file == -1)
  81     {
  82       fail(errno, ec);
  83       return;
  84     }
  85   }
  86
  87   size_t bytes_read = 0;
  88   while (bytes_read < len)
  89   {
  90     ssize_t n = read(file, buf, len - bytes_read);
  91     if (n == -1)
  92     {
  93       close(file);
  94       fail(errno, ec);
  95       return;
  96     }
  97     bytes_read += n;
  98     buf = static_cast<char*>(buf) + n;
  99   }
 100
 101   close(file);
 102
 103 # else // BOOST_WINDOWS_API
 104
 105   HCRYPTPROV handle;
 106   int errval = acquire_crypt_handle(handle);
 107
 108   if (!errval)
 109   {
 110     BOOL gen_ok = ::CryptGenRandom(handle, static_cast<DWORD>(len), static_cast<unsigned char*>(buf));
 111     if (!gen_ok)
 112       errval = ::GetLastError();
 113     ::CryptReleaseContext(handle, 0);
 114   }
 115
 116   if (!errval) return;
 117
 118   fail(errval, ec);
 119 # endif
 120 }
 121
 122 }  // unnamed namespace
 123
 124 namespace boost { namespace filesystem { namespace detail {
 125
 126 BOOST_FILESYSTEM_DECL
 127 path unique_path(const path& model, system::error_code* ec)
 128 {
 129   // This function used wstring for fear of misidentifying
 130   // a part of a multibyte character as a percent sign.
 131   // However, double byte encodings only have 80-FF as lead
 132   // bytes and 40-7F as trailing bytes, whereas % is 25.
 133   // So, use string on POSIX and avoid conversions.
 134
 135   path::string_type s( model.native() );
 136
 137 #ifdef BOOST_WINDOWS_API
 138   const wchar_t hex[] = L"0123456789abcdef";
 139   const wchar_t percent = L'%';
 140 #else
 141   const char hex[] = "0123456789abcdef";
 142   const char percent = '%';
 143 #endif
 144
 145   char ran[] = "123456789abcdef";  // init to avoid clang static analyzer message
 146                                    // see ticket #8954
 147   assert(sizeof(ran) == 16);
 148   const int max_nibbles = 2 * sizeof(ran);   // 4-bits per nibble
 149
 150   int nibbles_used = max_nibbles;
 151   for(path::string_type::size_type i=0; i < s.size(); ++i)
 152   {
 153     if (s[i] == percent)                     // digit request
 154     {
 155       if (nibbles_used == max_nibbles)
 156       {
 157         system_crypt_random(ran, sizeof(ran), ec);
 158         if (ec != 0 && *ec)
 159           return "";
 160         nibbles_used = 0;
 161       }
 162       int c = ran[nibbles_used/2];
 163       c >>= 4 * (nibbles_used++ & 1);  // if odd, shift right 1 nibble
 164       s[i] = hex[c & 0xf];             // convert to hex digit and replace
 165     }
 166   }
 167
 168   if (ec != 0) ec->clear();
 169
 170   return s;
 171 }
 172
 173 }}}