1 // Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Dynamic library facilities.
13 //! A simple wrapper over the platform's dynamic library facilities
16 #![allow(missing_docs)]
25 #[allow(missing_copy_implementations)]
26 pub struct DynamicLibrary {
30 impl Drop for DynamicLibrary {
32 match dl::check_for_errors_in(|| {
34 dl::close(self.handle)
38 Err(str) => panic!("{}", str)
44 // FIXME (#12938): Until DST lands, we cannot decompose &str into
45 // & and str, so we cannot usefully take ToCStr arguments by
46 // reference (without forcing an additional & around &str). So we
47 // are instead temporarily adding an instance for &Path, so that
48 // we can take ToCStr as owned. When DST lands, the &Path instance
49 // should be removed, and arguments bound by ToCStr should be
50 // passed by reference. (Here: in the `open` method.)
52 /// Lazily open a dynamic library. When passed None it gives a
53 /// handle to the calling process
54 pub fn open<T: ToCStr>(filename: Option<T>)
55 -> Result<DynamicLibrary, String> {
57 let mut filename = filename;
58 let maybe_library = dl::check_for_errors_in(|| {
59 match filename.take() {
60 Some(name) => dl::open_external(name),
61 None => dl::open_internal()
65 // The dynamic library must not be constructed if there is
66 // an error opening the library so the destructor does not
70 Ok(handle) => Ok(DynamicLibrary { handle: handle })
75 /// Prepends a path to this process's search path for dynamic libraries
76 pub fn prepend_search_path(path: &Path) {
77 let mut search_path = DynamicLibrary::search_path();
78 search_path.insert(0, path.clone());
79 let newval = DynamicLibrary::create_path(search_path.as_slice());
80 os::setenv(DynamicLibrary::envvar(),
81 str::from_utf8(newval.as_slice()).unwrap());
84 /// From a slice of paths, create a new vector which is suitable to be an
85 /// environment variable for this platforms dylib search path.
86 pub fn create_path(path: &[Path]) -> Vec<u8> {
87 let mut newvar = Vec::new();
88 for (i, path) in path.iter().enumerate() {
89 if i > 0 { newvar.push(DynamicLibrary::separator()); }
90 newvar.push_all(path.as_vec());
95 /// Returns the environment variable for this process's dynamic library
97 pub fn envvar() -> &'static str {
100 } else if cfg!(target_os = "macos") {
107 fn separator() -> u8 {
108 if cfg!(windows) {b';'} else {b':'}
111 /// Returns the current search path for dynamic libraries being used by this
113 pub fn search_path() -> Vec<Path> {
114 let mut ret = Vec::new();
115 match os::getenv_as_bytes(DynamicLibrary::envvar()) {
119 .split(|a| *a == DynamicLibrary::separator()) {
120 ret.push(Path::new(portion));
128 /// Access the value at the symbol of the dynamic library
129 pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<*mut T, String> {
130 // This function should have a lifetime constraint of 'a on
131 // T but that feature is still unimplemented
133 let maybe_symbol_value = dl::check_for_errors_in(|| {
134 symbol.with_c_str(|raw_string| {
135 dl::symbol(self.handle, raw_string)
139 // The value must not be constructed if there is an error so
140 // the destructor does not run.
141 match maybe_symbol_value {
142 Err(err) => Err(err),
143 Ok(symbol_value) => Ok(mem::transmute(symbol_value))
148 #[cfg(all(test, not(target_os = "ios")))]
156 #[cfg_attr(any(windows, target_os = "android"), ignore)] // FIXME #8818, #10379
157 fn test_loading_cosine() {
158 // The math library does not need to be loaded since it is already
159 // statically linked in
160 let none: Option<Path> = None; // appease the typechecker
161 let libm = match DynamicLibrary::open(none) {
162 Err(error) => panic!("Could not load self as module: {}", error),
166 let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
167 match libm.symbol("cos") {
168 Err(error) => panic!("Could not load function cos: {}", error),
169 Ok(cosine) => mem::transmute::<*mut u8, _>(cosine)
174 let expected_result = 1.0;
175 let result = cosine(argument);
176 if result != expected_result {
177 panic!("cos({}) != {} but equaled {} instead", argument,
178 expected_result, result)
183 #[cfg(any(target_os = "linux",
185 target_os = "freebsd",
186 target_os = "dragonfly"))]
187 fn test_errors_do_not_crash() {
188 // Open /dev/null as a library to get an error, and make sure
189 // that only causes an error, and not a crash.
190 let path = Path::new("/dev/null");
191 match DynamicLibrary::open(Some(&path)) {
193 Ok(_) => panic!("Successfully opened the empty library.")
198 #[cfg(any(target_os = "linux",
199 target_os = "android",
202 target_os = "freebsd",
203 target_os = "dragonfly"))]
208 use c_str::{CString, ToCStr};
212 pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
213 filename.with_c_str(|raw_name| {
214 dlopen(raw_name, Lazy as libc::c_int) as *mut u8
218 pub unsafe fn open_internal() -> *mut u8 {
219 dlopen(ptr::null(), Lazy as libc::c_int) as *mut u8
222 pub fn check_for_errors_in<T, F>(f: F) -> Result<T, String> where
225 use sync::{StaticMutex, MUTEX_INIT};
226 static LOCK: StaticMutex = MUTEX_INIT;
228 // dlerror isn't thread safe, so we need to lock around this entire
230 let _guard = LOCK.lock();
231 let _old_error = dlerror();
235 let last_error = dlerror() as *const _;
236 let ret = if ptr::null() == last_error {
239 Err(String::from_str(CString::new(last_error, false).as_str()
247 pub unsafe fn symbol(handle: *mut u8,
248 symbol: *const libc::c_char) -> *mut u8 {
249 dlsym(handle as *mut libc::c_void, symbol) as *mut u8
251 pub unsafe fn close(handle: *mut u8) {
252 dlclose(handle as *mut libc::c_void); ()
265 fn dlopen(filename: *const libc::c_char,
266 flag: libc::c_int) -> *mut libc::c_void;
267 fn dlerror() -> *mut libc::c_char;
268 fn dlsym(handle: *mut libc::c_void,
269 symbol: *const libc::c_char) -> *mut libc::c_void;
270 fn dlclose(handle: *mut libc::c_void) -> libc::c_int;
274 #[cfg(target_os = "windows")]
277 use iter::IteratorExt;
283 use result::Result::{Ok, Err};
290 pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
291 // Windows expects Unicode data
292 let filename_cstr = filename.to_c_str();
293 let filename_str = str::from_utf8(filename_cstr.as_bytes_no_nul()).unwrap();
294 let mut filename_str: Vec<u16> = filename_str.utf16_units().collect();
295 filename_str.push(0);
296 LoadLibraryW(filename_str.as_ptr() as *const libc::c_void) as *mut u8
299 pub unsafe fn open_internal() -> *mut u8 {
300 let mut handle = ptr::null_mut();
301 GetModuleHandleExW(0 as libc::DWORD, ptr::null(), &mut handle);
305 pub fn check_for_errors_in<T, F>(f: F) -> Result<T, String> where
313 let error = os::errno();
317 Err(format!("Error code {}", error))
322 pub unsafe fn symbol(handle: *mut u8, symbol: *const libc::c_char) -> *mut u8 {
323 GetProcAddress(handle as *mut libc::c_void, symbol) as *mut u8
325 pub unsafe fn close(handle: *mut u8) {
326 FreeLibrary(handle as *mut libc::c_void); ()
329 #[allow(non_snake_case)]
331 fn SetLastError(error: libc::size_t);
332 fn LoadLibraryW(name: *const libc::c_void) -> *mut libc::c_void;
333 fn GetModuleHandleExW(dwFlags: libc::DWORD, name: *const u16,
334 handle: *mut *mut libc::c_void)
335 -> *mut libc::c_void;
336 fn GetProcAddress(handle: *mut libc::c_void,
337 name: *const libc::c_char) -> *mut libc::c_void;
338 fn FreeLibrary(handle: *mut libc::c_void);