1// Copyright 2014 Renato Tegon Forti, Antony Polukhin.
2// Copyright Antony Polukhin, 2015-2024.
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/posix/path_from_handle.hpp>
14#include <boost/dll/detail/posix/program_location_impl.hpp>
15
16#include <boost/move/utility.hpp>
17#include <boost/core/invoke_swap.hpp>
18#include <boost/predef/os.h>
19
20#include <dlfcn.h>
21#include <cstring> // strncmp
22#if !BOOST_OS_MACOS && !BOOST_OS_IOS && !BOOST_OS_QNX
23# include <link.h>
24#elif BOOST_OS_QNX
25// QNX's copy of <elf.h> and <link.h> reside in sys folder
26# include <sys/link.h>
27#endif
28
29#ifdef BOOST_HAS_PRAGMA_ONCE
30# pragma once
31#endif
32
33namespace boost { namespace dll { namespace detail {
34
35class shared_library_impl {
36
37 BOOST_MOVABLE_BUT_NOT_COPYABLE(shared_library_impl)
38
39public:
40 typedef void* native_handle_t;
41
42 shared_library_impl() BOOST_NOEXCEPT
43 : handle_(NULL)
44 {}
45
46 ~shared_library_impl() BOOST_NOEXCEPT {
47 unload();
48 }
49
50 shared_library_impl(BOOST_RV_REF(shared_library_impl) sl) BOOST_NOEXCEPT
51 : handle_(sl.handle_)
52 {
53 sl.handle_ = NULL;
54 }
55
56 shared_library_impl & operator=(BOOST_RV_REF(shared_library_impl) sl) BOOST_NOEXCEPT {
57 swap(rhs&: sl);
58 return *this;
59 }
60
61
62 static boost::dll::fs::path decorate(const boost::dll::fs::path & sl) {
63 boost::dll::fs::path actual_path = (
64 std::strncmp(s1: sl.filename().string().c_str(), s2: "lib", n: 3)
65 ? boost::dll::fs::path((sl.has_parent_path() ? sl.parent_path() / "lib" : "lib").native() + sl.filename().native())
66 : sl
67 );
68 actual_path += suffix();
69 return actual_path;
70 }
71
72 void load(boost::dll::fs::path sl, load_mode::type portable_mode, boost::dll::fs::error_code &ec) {
73 typedef int native_mode_t;
74 native_mode_t native_mode = static_cast<native_mode_t>(portable_mode);
75 unload();
76
77 // Do not allow opening NULL paths. User must use program_location() instead
78 if (sl.empty()) {
79 boost::dll::detail::reset_dlerror();
80 ec = boost::dll::fs::make_error_code(
81 e: boost::dll::fs::errc::bad_file_descriptor
82 );
83
84 return;
85 }
86
87 // Fixing modes
88 if (!(native_mode & load_mode::rtld_now)) {
89 native_mode |= load_mode::rtld_lazy;
90 }
91
92 if (!(native_mode & load_mode::rtld_global)) {
93 native_mode |= load_mode::rtld_local;
94 }
95
96#if BOOST_OS_LINUX || BOOST_OS_ANDROID
97 if (!sl.has_parent_path() && !(native_mode & load_mode::search_system_folders)) {
98 sl = "." / sl;
99 }
100#else
101 if (!sl.is_absolute() && !(native_mode & load_mode::search_system_folders)) {
102 boost::dll::fs::error_code current_path_ec;
103 boost::dll::fs::path prog_loc = boost::dll::fs::current_path(current_path_ec);
104 if (!current_path_ec) {
105 prog_loc /= sl;
106 sl.swap(prog_loc);
107 }
108 }
109#endif
110
111 native_mode = static_cast<unsigned>(native_mode) & ~static_cast<unsigned>(load_mode::search_system_folders);
112
113 // Trying to open with appended decorations
114 if (!!(native_mode & load_mode::append_decorations)) {
115 native_mode = static_cast<unsigned>(native_mode) & ~static_cast<unsigned>(load_mode::append_decorations);
116
117 boost::dll::fs::path actual_path = decorate(sl);
118 handle_ = dlopen(file: actual_path.c_str(), mode: native_mode);
119 if (handle_) {
120 boost::dll::detail::reset_dlerror();
121 return;
122 }
123 boost::dll::fs::error_code prog_loc_err;
124 boost::dll::fs::path loc = boost::dll::detail::program_location_impl(ec&: prog_loc_err);
125 if (boost::dll::fs::exists(p: actual_path) && !boost::dll::fs::equivalent(p1: sl, p2: loc, ec&: prog_loc_err)) {
126 // decorated path exists : current error is not a bad file descriptor and we are not trying to load the executable itself
127 ec = boost::dll::fs::make_error_code(
128 e: boost::dll::fs::errc::executable_format_error
129 );
130 return;
131 }
132 }
133
134 // Opening by exactly specified path
135 handle_ = dlopen(file: sl.c_str(), mode: native_mode);
136 if (handle_) {
137 boost::dll::detail::reset_dlerror();
138 return;
139 }
140
141 ec = boost::dll::fs::make_error_code(
142 e: boost::dll::fs::errc::bad_file_descriptor
143 );
144
145 // Maybe user wanted to load the executable itself? Checking...
146 // We assume that usually user wants to load a dynamic library not the executable itself, that's why
147 // we try this only after traditional load fails.
148 boost::dll::fs::error_code prog_loc_err;
149 boost::dll::fs::path loc = boost::dll::detail::program_location_impl(ec&: prog_loc_err);
150 if (!prog_loc_err && boost::dll::fs::equivalent(p1: sl, p2: loc, ec&: prog_loc_err) && !prog_loc_err) {
151 // As is known the function dlopen() loads the dynamic library file
152 // named by the null-terminated string filename and returns an opaque
153 // "handle" for the dynamic library. If filename is NULL, then the
154 // returned handle is for the main program.
155 ec.clear();
156 boost::dll::detail::reset_dlerror();
157 handle_ = dlopen(NULL, mode: native_mode);
158 if (!handle_) {
159 ec = boost::dll::fs::make_error_code(
160 e: boost::dll::fs::errc::bad_file_descriptor
161 );
162 }
163 }
164 }
165
166 bool is_loaded() const BOOST_NOEXCEPT {
167 return (handle_ != 0);
168 }
169
170 void unload() BOOST_NOEXCEPT {
171 if (!is_loaded()) {
172 return;
173 }
174
175 dlclose(handle: handle_);
176 handle_ = 0;
177 }
178
179 void swap(shared_library_impl& rhs) BOOST_NOEXCEPT {
180 boost::core::invoke_swap(left&: handle_, right&: rhs.handle_);
181 }
182
183 boost::dll::fs::path full_module_path(boost::dll::fs::error_code &ec) const {
184 return boost::dll::detail::path_from_handle(handle: handle_, ec);
185 }
186
187 static boost::dll::fs::path suffix() {
188 // https://sourceforge.net/p/predef/wiki/OperatingSystems/
189#if BOOST_OS_MACOS || BOOST_OS_IOS
190 return ".dylib";
191#else
192 return ".so";
193#endif
194 }
195
196 void* symbol_addr(const char* sb, boost::dll::fs::error_code &ec) const BOOST_NOEXCEPT {
197 // dlsym - obtain the address of a symbol from a dlopen object
198 void* const symbol = dlsym(handle: handle_, name: sb);
199 if (symbol == NULL) {
200 ec = boost::dll::fs::make_error_code(
201 e: boost::dll::fs::errc::invalid_seek
202 );
203 }
204
205 // If handle does not refer to a valid object opened by dlopen(),
206 // or if the named symbol cannot be found within any of the objects
207 // associated with handle, dlsym() shall return NULL.
208 // More detailed diagnostic information shall be available through dlerror().
209
210 return symbol;
211 }
212
213 native_handle_t native() const BOOST_NOEXCEPT {
214 return handle_;
215 }
216
217private:
218 native_handle_t handle_;
219};
220
221}}} // boost::dll::detail
222
223#endif // BOOST_DLL_SHARED_LIBRARY_IMPL_HPP
224

source code of boost/libs/dll/include/boost/dll/detail/posix/shared_library_impl.hpp