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)]
20 use iter::IteratorExt;
25 use path::{Path,GenericPath};
27 use slice::{AsSlice,SlicePrelude};
32 pub struct DynamicLibrary { handle: *mut u8 }
34 impl Drop for DynamicLibrary {
36 match dl::check_for_errors_in(|| {
38 dl::close(self.handle)
42 Err(str) => panic!("{}", str)
48 // FIXME (#12938): Until DST lands, we cannot decompose &str into
49 // & and str, so we cannot usefully take ToCStr arguments by
50 // reference (without forcing an additional & around &str). So we
51 // are instead temporarily adding an instance for &Path, so that
52 // we can take ToCStr as owned. When DST lands, the &Path instance
53 // should be removed, and arguments bound by ToCStr should be
54 // passed by reference. (Here: in the `open` method.)
56 /// Lazily open a dynamic library. When passed None it gives a
57 /// handle to the calling process
58 pub fn open<T: ToCStr>(filename: Option<T>)
59 -> Result<DynamicLibrary, String> {
61 let mut filename = filename;
62 let maybe_library = dl::check_for_errors_in(|| {
63 match filename.take() {
64 Some(name) => dl::open_external(name),
65 None => dl::open_internal()
69 // The dynamic library must not be constructed if there is
70 // an error opening the library so the destructor does not
74 Ok(handle) => Ok(DynamicLibrary { handle: handle })
79 /// Prepends a path to this process's search path for dynamic libraries
80 pub fn prepend_search_path(path: &Path) {
81 let mut search_path = DynamicLibrary::search_path();
82 search_path.insert(0, path.clone());
83 let newval = DynamicLibrary::create_path(search_path.as_slice());
84 os::setenv(DynamicLibrary::envvar(),
85 str::from_utf8(newval.as_slice()).unwrap());
88 /// From a slice of paths, create a new vector which is suitable to be an
89 /// environment variable for this platforms dylib search path.
90 pub fn create_path(path: &[Path]) -> Vec<u8> {
91 let mut newvar = Vec::new();
92 for (i, path) in path.iter().enumerate() {
93 if i > 0 { newvar.push(DynamicLibrary::separator()); }
94 newvar.push_all(path.as_vec());
99 /// Returns the environment variable for this process's dynamic library
101 pub fn envvar() -> &'static str {
104 } else if cfg!(target_os = "macos") {
111 fn separator() -> u8 {
112 if cfg!(windows) {b';'} else {b':'}
115 /// Returns the current search path for dynamic libraries being used by this
117 pub fn search_path() -> Vec<Path> {
118 let mut ret = Vec::new();
119 match os::getenv_as_bytes(DynamicLibrary::envvar()) {
123 .split(|a| *a == DynamicLibrary::separator()) {
124 ret.push(Path::new(portion));
132 /// Access the value at the symbol of the dynamic library
133 pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<*mut T, String> {
134 // This function should have a lifetime constraint of 'a on
135 // T but that feature is still unimplemented
137 let maybe_symbol_value = dl::check_for_errors_in(|| {
138 symbol.with_c_str(|raw_string| {
139 dl::symbol(self.handle, raw_string)
143 // The value must not be constructed if there is an error so
144 // the destructor does not run.
145 match maybe_symbol_value {
146 Err(err) => Err(err),
147 Ok(symbol_value) => Ok(mem::transmute(symbol_value))
152 #[cfg(all(test, not(target_os = "ios")))]
160 #[cfg_attr(any(windows, target_os = "android"), ignore)] // FIXME #8818, #10379
161 fn test_loading_cosine() {
162 // The math library does not need to be loaded since it is already
163 // statically linked in
164 let none: Option<Path> = None; // appease the typechecker
165 let libm = match DynamicLibrary::open(none) {
166 Err(error) => panic!("Could not load self as module: {}", error),
170 let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
171 match libm.symbol("cos") {
172 Err(error) => panic!("Could not load function cos: {}", error),
173 Ok(cosine) => mem::transmute::<*mut u8, _>(cosine)
178 let expected_result = 1.0;
179 let result = cosine(argument);
180 if result != expected_result {
181 panic!("cos({}) != {} but equaled {} instead", argument,
182 expected_result, result)
187 #[cfg(any(target_os = "linux",
189 target_os = "freebsd",
190 target_os = "dragonfly"))]
191 fn test_errors_do_not_crash() {
192 // Open /dev/null as a library to get an error, and make sure
193 // that only causes an error, and not a crash.
194 let path = Path::new("/dev/null");
195 match DynamicLibrary::open(Some(&path)) {
197 Ok(_) => panic!("Successfully opened the empty library.")
202 #[cfg(any(target_os = "linux",
203 target_os = "android",
206 target_os = "freebsd",
207 target_os = "dragonfly"))]
209 pub use self::Rtld::*;
211 use c_str::{CString, ToCStr};
217 pub unsafe fn open_external<T: ToCStr>(filename: T) -> *mut u8 {
218 filename.with_c_str(|raw_name| {
219 dlopen(raw_name, Lazy as libc::c_int) as *mut u8
223 pub unsafe fn open_internal() -> *mut u8 {
224 dlopen(ptr::null(), Lazy as libc::c_int) as *mut u8
227 pub fn check_for_errors_in<T>(f: || -> T) -> Result<T, String> {
228 use rustrt::mutex::{StaticNativeMutex, NATIVE_MUTEX_INIT};
229 static LOCK: StaticNativeMutex = NATIVE_MUTEX_INIT;
231 // dlerror isn't thread safe, so we need to lock around this entire
233 let _guard = LOCK.lock();
234 let _old_error = dlerror();
238 let last_error = dlerror() as *const _;
239 let ret = if ptr::null() == last_error {
242 Err(String::from_str(CString::new(last_error, false).as_str()
250 pub unsafe fn symbol(handle: *mut u8,
251 symbol: *const libc::c_char) -> *mut u8 {
252 dlsym(handle as *mut libc::c_void, symbol) as *mut u8
254 pub unsafe fn close(handle: *mut u8) {
255 dlclose(handle as *mut libc::c_void); ()
267 fn dlopen(filename: *const libc::c_char,
268 flag: libc::c_int) -> *mut libc::c_void;
269 fn dlerror() -> *mut libc::c_char;
270 fn dlsym(handle: *mut libc::c_void,
271 symbol: *const libc::c_char) -> *mut libc::c_void;
272 fn dlclose(handle: *mut libc::c_void) -> libc::c_int;
276 #[cfg(target_os = "windows")]
279 use iter::IteratorExt;
283 use result::{Ok, Err, Result};
284 use slice::SlicePrelude;
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: || -> T) -> Result<T, String> {
311 let error = os::errno();
315 Err(format!("Error code {}", error))
320 pub unsafe fn symbol(handle: *mut u8, symbol: *const libc::c_char) -> *mut u8 {
321 GetProcAddress(handle as *mut libc::c_void, symbol) as *mut u8
323 pub unsafe fn close(handle: *mut u8) {
324 FreeLibrary(handle as *mut libc::c_void); ()
327 #[allow(non_snake_case)]
329 fn SetLastError(error: libc::size_t);
330 fn LoadLibraryW(name: *const libc::c_void) -> *mut libc::c_void;
331 fn GetModuleHandleExW(dwFlags: libc::DWORD, name: *const u16,
332 handle: *mut *mut libc::c_void)
333 -> *mut libc::c_void;
334 fn GetProcAddress(handle: *mut libc::c_void,
335 name: *const libc::c_char) -> *mut libc::c_void;
336 fn FreeLibrary(handle: *mut libc::c_void);