1 // Copyright 2014 Renato Tegon Forti, Antony Polukhin.
2 // Copyright 2015-2019 Antony Polukhin.
3 //
4 // Distributed under the Boost Software License, Version 1.0.
5 // (See accompanying file LICENSE_1_0.txt
6 // or copy at http://www.boost.org/LICENSE_1_0.txt)
7 
8 #ifndef BOOST_DLL_SHARED_LIBRARY_IMPL_HPP
9 #define BOOST_DLL_SHARED_LIBRARY_IMPL_HPP
10 
11 #include <boost/dll/config.hpp>
12 #include <boost/dll/shared_library_load_mode.hpp>
13 #include <boost/dll/detail/aggressive_ptr_cast.hpp>
14 #include <boost/dll/detail/system_error.hpp>
15 #include <boost/dll/detail/windows/path_from_handle.hpp>
16 
17 #include <boost/move/utility.hpp>
18 #include <boost/swap.hpp>
19 
20 #include <boost/winapi/dll.hpp>
21 
22 #ifdef BOOST_HAS_PRAGMA_ONCE
23 # pragma once
24 #endif
25 
26 namespace boost { namespace dll { namespace detail {
27 
28 class shared_library_impl {
29     BOOST_MOVABLE_BUT_NOT_COPYABLE(shared_library_impl)
30 
31 public:
32     typedef boost::winapi::HMODULE_ native_handle_t;
33 
shared_library_impl()34     shared_library_impl() BOOST_NOEXCEPT
35         : handle_(NULL)
36     {}
37 
~shared_library_impl()38     ~shared_library_impl() BOOST_NOEXCEPT {
39         unload();
40     }
41 
shared_library_impl(BOOST_RV_REF (shared_library_impl)sl)42     shared_library_impl(BOOST_RV_REF(shared_library_impl) sl) BOOST_NOEXCEPT
43         : handle_(sl.handle_)
44     {
45         sl.handle_ = NULL;
46     }
47 
operator =(BOOST_RV_REF (shared_library_impl)sl)48     shared_library_impl & operator=(BOOST_RV_REF(shared_library_impl) sl) BOOST_NOEXCEPT {
49         swap(sl);
50         return *this;
51     }
52 
decorate(const boost::dll::fs::path & sl)53     static boost::dll::fs::path decorate(const boost::dll::fs::path& sl) {
54         boost::dll::fs::path actual_path = sl;
55         actual_path += suffix();
56         return actual_path;
57     }
58 
load(boost::dll::fs::path sl,load_mode::type portable_mode,boost::dll::fs::error_code & ec)59     void load(boost::dll::fs::path sl, load_mode::type portable_mode, boost::dll::fs::error_code &ec) {
60         typedef boost::winapi::DWORD_ native_mode_t;
61         native_mode_t native_mode = static_cast<native_mode_t>(portable_mode);
62         unload();
63 
64         if (!sl.is_absolute() && !(native_mode & load_mode::search_system_folders)) {
65             boost::dll::fs::error_code current_path_ec;
66             boost::dll::fs::path prog_loc = boost::dll::fs::current_path(current_path_ec);
67 
68             if (!current_path_ec) {
69                 prog_loc /= sl;
70                 sl.swap(prog_loc);
71             }
72         }
73         native_mode = static_cast<unsigned>(native_mode) & ~static_cast<unsigned>(load_mode::search_system_folders);
74 
75         // Trying to open with appended decorations
76         if (!!(native_mode & load_mode::append_decorations)) {
77             native_mode = static_cast<unsigned>(native_mode) & ~static_cast<unsigned>(load_mode::append_decorations);
78 
79             if (load_impl(decorate(sl), native_mode, ec)) {
80                 return;
81             }
82 
83             // MinGW loves 'lib' prefix and puts it even on Windows platform.
84             const boost::dll::fs::path mingw_load_path = (
85                 sl.has_parent_path()
86                 ? sl.parent_path() / L"lib"
87                 : L"lib"
88             ).native() + sl.filename().native() + suffix().native();
89             if (load_impl(mingw_load_path, native_mode, ec)) {
90                 return;
91             }
92         }
93 
94         // From MSDN: If the string specifies a module name without a path and the
95         // file name extension is omitted, the function appends the default library
96         // extension .dll to the module name.
97         //
98         // From experiments: Default library extension appended to the module name even if
99         // we have some path. So we do not check for path, only for extension. We can not be sure that
100         // such behavior remain across all platforms, so we add L"." by hand.
101         if (sl.has_extension()) {
102             handle_ = boost::winapi::LoadLibraryExW(sl.c_str(), 0, native_mode);
103         } else {
104             handle_ = boost::winapi::LoadLibraryExW((sl.native() + L".").c_str(), 0, native_mode);
105         }
106 
107         // LoadLibraryExW method is capable of self loading from program_location() path. No special actions
108         // must be taken to allow self loading.
109         if (!handle_) {
110             ec = boost::dll::detail::last_error_code();
111         }
112     }
113 
is_loaded() const114     bool is_loaded() const BOOST_NOEXCEPT {
115         return (handle_ != 0);
116     }
117 
unload()118     void unload() BOOST_NOEXCEPT {
119         if (handle_) {
120             boost::winapi::FreeLibrary(handle_);
121             handle_ = 0;
122         }
123     }
124 
swap(shared_library_impl & rhs)125     void swap(shared_library_impl& rhs) BOOST_NOEXCEPT {
126         boost::swap(handle_, rhs.handle_);
127     }
128 
full_module_path(boost::dll::fs::error_code & ec) const129     boost::dll::fs::path full_module_path(boost::dll::fs::error_code &ec) const {
130         return boost::dll::detail::path_from_handle(handle_, ec);
131     }
132 
suffix()133     static boost::dll::fs::path suffix() {
134         return L".dll";
135     }
136 
symbol_addr(const char * sb,boost::dll::fs::error_code & ec) const137     void* symbol_addr(const char* sb, boost::dll::fs::error_code &ec) const BOOST_NOEXCEPT {
138         if (is_resource()) {
139             // `GetProcAddress` could not be called for libraries loaded with
140             // `LOAD_LIBRARY_AS_DATAFILE`, `LOAD_LIBRARY_AS_DATAFILE_EXCLUSIVE`
141             // or `LOAD_LIBRARY_AS_IMAGE_RESOURCE`.
142             ec = boost::dll::fs::make_error_code(
143                 boost::dll::fs::errc::operation_not_supported
144             );
145 
146             return NULL;
147         }
148 
149         // Judging by the documentation of GetProcAddress
150         // there is no version for UNICODE on desktop/server Windows, because
151         // names of functions are stored in narrow characters.
152         void* const symbol = boost::dll::detail::aggressive_ptr_cast<void*>(
153             boost::winapi::get_proc_address(handle_, sb)
154         );
155         if (symbol == NULL) {
156             ec = boost::dll::detail::last_error_code();
157         }
158 
159         return symbol;
160     }
161 
native() const162     native_handle_t native() const BOOST_NOEXCEPT {
163         return handle_;
164     }
165 
166 private:
167     // Returns true if this load attempt should be the last one.
load_impl(const boost::dll::fs::path & load_path,boost::winapi::DWORD_ mode,boost::dll::fs::error_code & ec)168     bool load_impl(const boost::dll::fs::path &load_path, boost::winapi::DWORD_ mode, boost::dll::fs::error_code &ec) {
169         handle_ = boost::winapi::LoadLibraryExW(load_path.c_str(), 0, mode);
170         if (handle_) {
171             return true;
172         }
173 
174         ec = boost::dll::detail::last_error_code();
175         if (boost::dll::fs::exists(load_path)) {
176             // decorated path exists : current error is not a bad file descriptor
177             return true;
178         }
179 
180         ec.clear();
181         return false;
182     }
183 
is_resource() const184     bool is_resource() const BOOST_NOEXCEPT {
185         return false; /*!!(
186             reinterpret_cast<boost::winapi::ULONG_PTR_>(handle_) & static_cast<boost::winapi::ULONG_PTR_>(3)
187         );*/
188     }
189 
190     native_handle_t handle_;
191 };
192 
193 }}} // boost::dll::detail
194 
195 #endif // BOOST_DLL_SHARED_LIBRARY_IMPL_HPP
196