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7c673cae FG |
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 | ||
92f5a8d4 | 10 | //--------------------------------------------------------------------------------------// |
7c673cae | 11 | |
92f5a8d4 | 12 | #ifndef BOOST_SYSTEM_NO_DEPRECATED |
7c673cae FG |
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> | |
b32b8144 FG |
27 | # ifdef _MSC_VER |
28 | # pragma comment(lib, "Advapi32.lib") | |
29 | # endif | |
7c673cae FG |
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 | { | |
92f5a8d4 | 110 | BOOL gen_ok = ::CryptGenRandom(handle, static_cast<DWORD>(len), static_cast<unsigned char*>(buf)); |
7c673cae FG |
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 | { | |
92f5a8d4 TL |
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 | |
7c673cae | 138 | const wchar_t hex[] = L"0123456789abcdef"; |
92f5a8d4 TL |
139 | const wchar_t percent = L'%'; |
140 | #else | |
141 | const char hex[] = "0123456789abcdef"; | |
142 | const char percent = '%'; | |
143 | #endif | |
144 | ||
7c673cae FG |
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; | |
92f5a8d4 | 151 | for(path::string_type::size_type i=0; i < s.size(); ++i) |
7c673cae | 152 | { |
92f5a8d4 | 153 | if (s[i] == percent) // digit request |
7c673cae FG |
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 | }}} |