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.
13 Dynamic library facilities.
15 A simple wrapper over the platform's dynamic library facilities
20 #![allow(missing_doc)]
23 use collections::MutableSeq;
30 use path::{Path,GenericPath};
32 use slice::{Slice,ImmutableSlice};
37 pub struct DynamicLibrary { handle: *mut u8 }
39 impl Drop for DynamicLibrary {
41 match dl::check_for_errors_in(|| {
43 dl::close(self.handle)
47 Err(str) => fail!("{}", str)
53 // FIXME (#12938): Until DST lands, we cannot decompose &str into
54 // & and str, so we cannot usefully take ToCStr arguments by
55 // reference (without forcing an additional & around &str). So we
56 // are instead temporarily adding an instance for &Path, so that
57 // we can take ToCStr as owned. When DST lands, the &Path instance
58 // should be removed, and arguments bound by ToCStr should be
59 // passed by reference. (Here: in the `open` method.)
61 /// Lazily open a dynamic library. When passed None it gives a
62 /// handle to the calling process
63 pub fn open<T: ToCStr>(filename: Option<T>)
64 -> Result<DynamicLibrary, String> {
66 let mut filename = filename;
67 let maybe_library = dl::check_for_errors_in(|| {
68 match filename.take() {
69 Some(name) => dl::open_external(name),
70 None => dl::open_internal()
74 // The dynamic library must not be constructed if there is
75 // an error opening the library so the destructor does not
79 Ok(handle) => Ok(DynamicLibrary { handle: handle })
84 /// Prepends a path to this process's search path for dynamic libraries
85 pub fn prepend_search_path(path: &Path) {
86 let mut search_path = DynamicLibrary::search_path();
87 search_path.insert(0, path.clone());
88 let newval = DynamicLibrary::create_path(search_path.as_slice());
89 os::setenv(DynamicLibrary::envvar(),
90 str::from_utf8(newval.as_slice()).unwrap());
93 /// From a slice of paths, create a new vector which is suitable to be an
94 /// environment variable for this platforms dylib search path.
95 pub fn create_path(path: &[Path]) -> Vec<u8> {
96 let mut newvar = Vec::new();
97 for (i, path) in path.iter().enumerate() {
98 if i > 0 { newvar.push(DynamicLibrary::separator()); }
99 newvar.push_all(path.as_vec());
104 /// Returns the environment variable for this process's dynamic library
106 pub fn envvar() -> &'static str {
109 } else if cfg!(target_os = "macos") {
116 fn separator() -> u8 {
117 if cfg!(windows) {b';'} else {b':'}
120 /// Returns the current search path for dynamic libraries being used by this
122 pub fn search_path() -> Vec<Path> {
123 let mut ret = Vec::new();
124 match os::getenv_as_bytes(DynamicLibrary::envvar()) {
128 .split(|a| *a == DynamicLibrary::separator()) {
129 ret.push(Path::new(portion));
137 /// Access the value at the symbol of the dynamic library
138 pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<*mut T, String> {
139 // This function should have a lifetime constraint of 'a on
140 // T but that feature is still unimplemented
142 let maybe_symbol_value = dl::check_for_errors_in(|| {
143 symbol.with_c_str(|raw_string| {
144 dl::symbol(self.handle, raw_string)
148 // The value must not be constructed if there is an error so
149 // the destructor does not run.
150 match maybe_symbol_value {
151 Err(err) => Err(err),
152 Ok(symbol_value) => Ok(mem::transmute(symbol_value))
157 #[cfg(test, not(target_os = "ios"))]
165 #[ignore(cfg(windows))] // FIXME #8818
166 #[ignore(cfg(target_os="android"))] // FIXME(#10379)
167 fn test_loading_cosine() {
168 // The math library does not need to be loaded since it is already
169 // statically linked in
170 let none: Option<Path> = None; // appease the typechecker
171 let libm = match DynamicLibrary::open(none) {
172 Err(error) => fail!("Could not load self as module: {}", error),
176 let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
177 match libm.symbol("cos") {
178 Err(error) => fail!("Could not load function cos: {}", error),
179 Ok(cosine) => mem::transmute::<*mut u8, _>(cosine)
184 let expected_result = 1.0;
185 let result = cosine(argument);
186 if result != expected_result {
187 fail!("cos({:?}) != {:?} but equaled {:?} instead", argument,
188 expected_result, result)
193 #[cfg(target_os = "linux")]
194 #[cfg(target_os = "macos")]
195 #[cfg(target_os = "freebsd")]
196 #[cfg(target_os = "dragonfly")]
197 fn test_errors_do_not_crash() {
198 // Open /dev/null as a library to get an error, and make sure
199 // that only causes an error, and not a crash.
200 let path = Path::new("/dev/null");
201 match DynamicLibrary::open(Some(&path)) {
203 Ok(_) => fail!("Successfully opened the empty library.")
208 #[cfg(target_os = "linux")]
209 #[cfg(target_os = "android")]
210 #[cfg(target_os = "macos")]
211 #[cfg(target_os = "ios")]
212 #[cfg(target_os = "freebsd")]
213 #[cfg(target_os = "dragonfly")]
216 use c_str::{CString, ToCStr};
222 pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
223 filename.with_c_str(|raw_name| {
224 dlopen(raw_name, Lazy as libc::c_int) as *mut u8
228 pub unsafe fn open_internal() -> *mut u8 {
229 dlopen(ptr::null(), Lazy as libc::c_int) as *mut u8
232 pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, String> {
233 use rt::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
234 static mut lock: StaticNativeMutex = NATIVE_MUTEX_INIT;
236 // dlerror isn't thread safe, so we need to lock around this entire
238 let _guard = lock.lock();
239 let _old_error = dlerror();
243 let last_error = dlerror() as *const _;
244 let ret = if ptr::null() == last_error {
247 Err(String::from_str(CString::new(last_error, false).as_str()
255 pub unsafe fn symbol(handle: *mut u8,
256 symbol: *const libc::c_char) -> *mut u8 {
257 dlsym(handle as *mut libc::c_void, symbol) as *mut u8
259 pub unsafe fn close(handle: *mut u8) {
260 dlclose(handle as *mut libc::c_void); ()
272 fn dlopen(filename: *const libc::c_char,
273 flag: libc::c_int) -> *mut libc::c_void;
274 fn dlerror() -> *mut libc::c_char;
275 fn dlsym(handle: *mut libc::c_void,
276 symbol: *const libc::c_char) -> *mut libc::c_void;
277 fn dlclose(handle: *mut libc::c_void) -> libc::c_int;
281 #[cfg(target_os = "win32")]
288 use result::{Ok, Err, Result};
294 pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
295 // Windows expects Unicode data
296 let filename_cstr = filename.to_c_str();
297 let filename_str = str::from_utf8(filename_cstr.as_bytes_no_nul()).unwrap();
298 let filename_str: Vec<u16> = filename_str.utf16_units().collect();
299 let filename_str = filename_str.append_one(0);
300 LoadLibraryW(filename_str.as_ptr() as *const libc::c_void) as *mut u8
303 pub unsafe fn open_internal() -> *mut u8 {
304 let mut handle = ptr::mut_null();
305 GetModuleHandleExW(0 as libc::DWORD, ptr::null(), &mut handle);
309 pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, String> {
315 let error = os::errno();
319 Err(format!("Error code {}", error))
324 pub unsafe fn symbol(handle: *mut u8, symbol: *const libc::c_char) -> *mut u8 {
325 GetProcAddress(handle as *mut libc::c_void, symbol) as *mut u8
327 pub unsafe fn close(handle: *mut u8) {
328 FreeLibrary(handle as *mut libc::c_void); ()
331 #[allow(non_snake_case_functions)]
333 fn SetLastError(error: libc::size_t);
334 fn LoadLibraryW(name: *const libc::c_void) -> *mut libc::c_void;
335 fn GetModuleHandleExW(dwFlags: libc::DWORD, name: *const u16,
336 handle: *mut *mut libc::c_void)
337 -> *mut libc::c_void;
338 fn GetProcAddress(handle: *mut libc::c_void,
339 name: *const libc::c_char) -> *mut libc::c_void;
340 fn FreeLibrary(handle: *mut libc::c_void);