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 mode,boost::dll::fs::error_code & ec)59     void load(boost::dll::fs::path sl, load_mode::type mode, boost::dll::fs::error_code &ec) {
60         typedef boost::winapi::DWORD_ native_mode_t;
61         unload();
62 
63         if (!sl.is_absolute() && !(mode & load_mode::search_system_folders)) {
64             boost::dll::fs::error_code current_path_ec;
65             boost::dll::fs::path prog_loc = boost::dll::fs::current_path(current_path_ec);
66 
67             if (!current_path_ec) {
68                 prog_loc /= sl;
69                 sl.swap(prog_loc);
70             }
71         }
72         mode &= ~load_mode::search_system_folders;
73 
74         // Trying to open with appended decorations
75         if (!!(mode & load_mode::append_decorations)) {
76             mode &= ~load_mode::append_decorations;
77 
78             if (load_impl(decorate(sl), static_cast<native_mode_t>(mode), ec)) {
79                 return;
80             }
81 
82             // MinGW loves 'lib' prefix and puts it even on Windows platform.
83             const boost::dll::fs::path mingw_load_path = (
84                 sl.has_parent_path()
85                 ? sl.parent_path() / L"lib"
86                 : L"lib"
87             ).native() + sl.filename().native() + suffix().native();
88             if (load_impl(mingw_load_path, static_cast<native_mode_t>(mode), ec)) {
89                 return;
90             }
91         }
92 
93         // From MSDN: If the string specifies a module name without a path and the
94         // file name extension is omitted, the function appends the default library
95         // extension .dll to the module name.
96         //
97         // From experiments: Default library extension appended to the module name even if
98         // we have some path. So we do not check for path, only for extension. We can not be sure that
99         // such behavior remain across all platforms, so we add L"." by hand.
100         if (sl.has_extension()) {
101             handle_ = boost::winapi::LoadLibraryExW(sl.c_str(), 0, static_cast<native_mode_t>(mode));
102         } else {
103             handle_ = boost::winapi::LoadLibraryExW((sl.native() + L".").c_str(), 0, static_cast<native_mode_t>(mode));
104         }
105 
106         // LoadLibraryExW method is capable of self loading from program_location() path. No special actions
107         // must be taken to allow self loading.
108         if (!handle_) {
109             ec = boost::dll::detail::last_error_code();
110         }
111     }
112 
is_loaded() const113     bool is_loaded() const BOOST_NOEXCEPT {
114         return (handle_ != 0);
115     }
116 
unload()117     void unload() BOOST_NOEXCEPT {
118         if (handle_) {
119             boost::winapi::FreeLibrary(handle_);
120             handle_ = 0;
121         }
122     }
123 
swap(shared_library_impl & rhs)124     void swap(shared_library_impl& rhs) BOOST_NOEXCEPT {
125         boost::swap(handle_, rhs.handle_);
126     }
127 
full_module_path(boost::dll::fs::error_code & ec) const128     boost::dll::fs::path full_module_path(boost::dll::fs::error_code &ec) const {
129         return boost::dll::detail::path_from_handle(handle_, ec);
130     }
131 
suffix()132     static boost::dll::fs::path suffix() {
133         return L".dll";
134     }
135 
symbol_addr(const char * sb,boost::dll::fs::error_code & ec) const136     void* symbol_addr(const char* sb, boost::dll::fs::error_code &ec) const BOOST_NOEXCEPT {
137         if (is_resource()) {
138             // `GetProcAddress` could not be called for libraries loaded with
139             // `LOAD_LIBRARY_AS_DATAFILE`, `LOAD_LIBRARY_AS_DATAFILE_EXCLUSIVE`
140             // or `LOAD_LIBRARY_AS_IMAGE_RESOURCE`.
141             ec = boost::dll::fs::make_error_code(
142                 boost::dll::fs::errc::operation_not_supported
143             );
144 
145             return NULL;
146         }
147 
148         // Judging by the documentation of GetProcAddress
149         // there is no version for UNICODE on desktop/server Windows, because
150         // names of functions are stored in narrow characters.
151         void* const symbol = boost::dll::detail::aggressive_ptr_cast<void*>(
152             boost::winapi::get_proc_address(handle_, sb)
153         );
154         if (symbol == NULL) {
155             ec = boost::dll::detail::last_error_code();
156         }
157 
158         return symbol;
159     }
160 
native() const161     native_handle_t native() const BOOST_NOEXCEPT {
162         return handle_;
163     }
164 
165 private:
166     // 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)167     bool load_impl(const boost::dll::fs::path &load_path, boost::winapi::DWORD_ mode, boost::dll::fs::error_code &ec) {
168         handle_ = boost::winapi::LoadLibraryExW(load_path.c_str(), 0, mode);
169         if (handle_) {
170             return true;
171         }
172 
173         ec = boost::dll::detail::last_error_code();
174         if (boost::dll::fs::exists(load_path)) {
175             // decorated path exists : current error is not a bad file descriptor
176             return true;
177         }
178 
179         ec.clear();
180         return false;
181     }
182 
is_resource() const183     bool is_resource() const BOOST_NOEXCEPT {
184         return false; /*!!(
185             reinterpret_cast<boost::winapi::ULONG_PTR_>(handle_) & static_cast<boost::winapi::ULONG_PTR_>(3)
186         );*/
187     }
188 
189     native_handle_t handle_;
190 };
191 
192 }}} // boost::dll::detail
193 
194 #endif // BOOST_DLL_SHARED_LIBRARY_IMPL_HPP
195