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// Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Dynamic library facilities.
//!
//! A simple wrapper over the platform's dynamic library facilities
extern crate libc;
use std::env;
use std::ffi::{CString, OsString};
use std::mem;
use std::path::{Path, PathBuf};
pub struct DynamicLibrary {
handle: *mut u8
}
impl Drop for DynamicLibrary {
fn drop(&mut self) {
match dl::check_for_errors_in(|| {
unsafe {
dl::close(self.handle)
}
}) {
Ok(()) => {},
Err(str) => panic!("{}", str)
}
}
}
impl DynamicLibrary {
// FIXME (#12938): Until DST lands, we cannot decompose &str into
// & and str, so we cannot usefully take ToCStr arguments by
// reference (without forcing an additional & around &str). So we
// are instead temporarily adding an instance for &Path, so that
// we can take ToCStr as owned. When DST lands, the &Path instance
// should be removed, and arguments bound by ToCStr should be
// passed by reference. (Here: in the `open` method.)
/// Lazily open a dynamic library. When passed None it gives a
/// handle to the calling process
pub fn open(filename: Option<&Path>) -> Result<DynamicLibrary, String> {
let maybe_library = dl::open(filename.map(|path| path.as_os_str()));
// The dynamic library must not be constructed if there is
// an error opening the library so the destructor does not
// run.
match maybe_library {
Err(err) => Err(err),
Ok(handle) => Ok(DynamicLibrary { handle: handle })
}
}
/// Prepends a path to this process's search path for dynamic libraries
pub fn prepend_search_path(path: &Path) {
let mut search_path = DynamicLibrary::search_path();
search_path.insert(0, path.to_path_buf());
env::set_var(DynamicLibrary::envvar(), &DynamicLibrary::create_path(&search_path));
}
/// From a slice of paths, create a new vector which is suitable to be an
/// environment variable for this platforms dylib search path.
pub fn create_path(path: &[PathBuf]) -> OsString {
let mut newvar = OsString::new();
for (i, path) in path.iter().enumerate() {
if i > 0 { newvar.push(DynamicLibrary::separator()); }
newvar.push(path);
}
return newvar;
}
/// Returns the environment variable for this process's dynamic library
/// search path
pub fn envvar() -> &'static str {
if cfg!(windows) {
"PATH"
} else if cfg!(target_os = "macos") {
"DYLD_LIBRARY_PATH"
} else {
"LD_LIBRARY_PATH"
}
}
fn separator() -> &'static str {
if cfg!(windows) { ";" } else { ":" }
}
/// Returns the current search path for dynamic libraries being used by this
/// process
pub fn search_path() -> Vec<PathBuf> {
match env::var_os(DynamicLibrary::envvar()) {
Some(var) => env::split_paths(&var).collect(),
None => Vec::new(),
}
}
/// Access the value at the symbol of the dynamic library
pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<*mut T, String> {
// This function should have a lifetime constraint of 'a on
// T but that feature is still unimplemented
let raw_string = CString::new(symbol).unwrap();
let maybe_symbol_value = dl::check_for_errors_in(|| {
dl::symbol(self.handle, raw_string.as_ptr())
});
// The value must not be constructed if there is an error so
// the destructor does not run.
match maybe_symbol_value {
Err(err) => Err(err),
Ok(symbol_value) => Ok(mem::transmute(symbol_value))
}
}
}
#[cfg(all(test, not(target_os = "ios")))]
mod test {
use super::*;
use std::mem;
use path::Path;
#[test]
#[cfg_attr(any(windows, target_os = "android"), ignore)] // FIXME #8818, #10379
fn test_loading_cosine() {
// The math library does not need to be loaded since it is already
// statically linked in
let libm = match DynamicLibrary::open(None) {
Err(error) => panic!("Could not load self as module: {}", error),
Ok(libm) => libm
};
let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
match libm.symbol("cos") {
Err(error) => panic!("Could not load function cos: {}", error),
Ok(cosine) => mem::transmute::<*mut u8, _>(cosine)
}
};
let argument = 0.0;
let expected_result = 1.0;
let result = cosine(argument);
if result != expected_result {
panic!("cos({}) != {} but equaled {} instead", argument,
expected_result, result)
}
}
#[test]
#[cfg(any(target_os = "linux",
target_os = "macos",
target_os = "freebsd",
target_os = "dragonfly",
target_os = "bitrig",
target_os = "openbsd"))]
fn test_errors_do_not_crash() {
// Open /dev/null as a library to get an error, and make sure
// that only causes an error, and not a crash.
let path = Path::new("/dev/null");
match DynamicLibrary::open(Some(&path)) {
Err(_) => {}
Ok(_) => panic!("Successfully opened the empty library.")
}
}
}
#[cfg(any(target_os = "linux",
target_os = "android",
target_os = "macos",
target_os = "ios",
target_os = "freebsd",
target_os = "dragonfly",
target_os = "bitrig",
target_os = "openbsd"))]
mod dl {
use std::ffi::{CStr, OsStr, CString};
use std::os::unix::ffi::OsStrExt;
use std::str;
use std::ptr;
use libc;
pub fn open(filename: Option<&OsStr>) -> Result<*mut u8, String> {
check_for_errors_in(|| {
unsafe {
match filename {
Some(filename) => open_external(filename),
None => open_internal(),
}
}
})
}
const LAZY: libc::c_int = 1;
unsafe fn open_external(filename: &OsStr) -> *mut u8 {
let s = CString::new(filename.as_bytes()).unwrap(); //to_cstring().unwrap();
dlopen(s.as_ptr(), LAZY) as *mut u8
}
unsafe fn open_internal() -> *mut u8 {
dlopen(ptr::null(), LAZY) as *mut u8
}
pub fn check_for_errors_in<T, F>(f: F) -> Result<T, String> where
F: FnOnce() -> T,
{
//use std::sync::{StaticMutex, MUTEX_INIT};
//static LOCK: StaticMutex = MUTEX_INIT;
unsafe {
//dlerror isn't thread safe, so we need to lock around this entire
//sequence
//let _guard = LOCK.lock();
//let _old_error = dlerror();
let result = f();
let last_error = dlerror() as *const _;
let ret = if ptr::null() == last_error {
Ok(result)
} else {
let s = CStr::from_ptr(last_error).to_bytes();
Err(str::from_utf8(s).unwrap().to_string())
};
ret
}
}
pub unsafe fn symbol(handle: *mut u8,
symbol: *const libc::c_char) -> *mut u8 {
dlsym(handle as *mut libc::c_void, symbol) as *mut u8
}
pub unsafe fn close(handle: *mut u8) {
dlclose(handle as *mut libc::c_void); ()
}
extern {
fn dlopen(filename: *const libc::c_char,
flag: libc::c_int) -> *mut libc::c_void;
fn dlerror() -> *mut libc::c_char;
fn dlsym(handle: *mut libc::c_void,
symbol: *const libc::c_char) -> *mut libc::c_void;
fn dlclose(handle: *mut libc::c_void) -> libc::c_int;
}
}
#[cfg(target_os = "windows")]
mod dl {
use std::ffi::OsStr;
use std::iter::Iterator;
use std::libc::consts::os::extra::ERROR_CALL_NOT_IMPLEMENTED;
use std::ops::FnOnce;
use std::sys::os;
use std::os::windows::prelude::*;
use std::option::Option::{self, Some, None};
use std::ptr;
use std::result::Result;
use std::result::Result::{Ok, Err};
use std::string::String;
use std::vec::Vec;
use std::sys::c::compat::kernel32::SetThreadErrorMode;
pub fn open(filename: Option<&OsStr>) -> Result<*mut u8, String> {
// disable "dll load failed" error dialog.
let mut use_thread_mode = true;
let prev_error_mode = unsafe {
// SEM_FAILCRITICALERRORS 0x01
let new_error_mode = 1;
let mut prev_error_mode = 0;
// Windows >= 7 supports thread error mode.
let result = SetThreadErrorMode(new_error_mode, &mut prev_error_mode);
if result == 0 {
let err = os::errno();
if err as libc::c_int == ERROR_CALL_NOT_IMPLEMENTED {
use_thread_mode = false;
// SetThreadErrorMode not found. use fallback solution:
// SetErrorMode() Note that SetErrorMode is process-wide so
// this can cause race condition! However, since even
// Windows APIs do not care of such problem (#20650), we
// just assume SetErrorMode race is not a great deal.
prev_error_mode = SetErrorMode(new_error_mode);
}
}
prev_error_mode
};
unsafe {
SetLastError(0);
}
let result = match filename {
Some(filename) => {
let filename_str: Vec<_> =
filename.encode_wide().chain(Some(0).into_iter()).collect();
let result = unsafe {
LoadLibraryW(filename_str.as_ptr() as *const libc::c_void)
};
// beware: Vec/String may change errno during drop!
// so we get error here.
if result == ptr::null_mut() {
let errno = os::errno();
Err(os::error_string(errno))
} else {
Ok(result as *mut u8)
}
}
None => {
let mut handle = ptr::null_mut();
let succeeded = unsafe {
GetModuleHandleExW(0 as libc::DWORD, ptr::null(), &mut handle)
};
if succeeded == libc::FALSE {
let errno = os::errno();
Err(os::error_string(errno))
} else {
Ok(handle as *mut u8)
}
}
};
unsafe {
if use_thread_mode {
SetThreadErrorMode(prev_error_mode, ptr::null_mut());
} else {
SetErrorMode(prev_error_mode);
}
}
result
}
pub fn check_for_errors_in<T, F>(f: F) -> Result<T, String> where
F: FnOnce() -> T,
{
unsafe {
SetLastError(0);
let result = f();
let error = os::errno();
if 0 == error {
Ok(result)
} else {
Err(format!("Error code {}", error))
}
}
}
pub unsafe fn symbol(handle: *mut u8, symbol: *const libc::c_char) -> *mut u8 {
GetProcAddress(handle as *mut libc::c_void, symbol) as *mut u8
}
pub unsafe fn close(handle: *mut u8) {
FreeLibrary(handle as *mut libc::c_void); ()
}
#[allow(non_snake_case)]
extern "system" {
fn SetLastError(error: libc::size_t);
fn LoadLibraryW(name: *const libc::c_void) -> *mut libc::c_void;
fn GetModuleHandleExW(dwFlags: libc::DWORD, name: *const u16,
handle: *mut *mut libc::c_void) -> libc::BOOL;
fn GetProcAddress(handle: *mut libc::c_void,
name: *const libc::c_char) -> *mut libc::c_void;
fn FreeLibrary(handle: *mut libc::c_void);
fn SetErrorMode(uMode: libc::c_uint) -> libc::c_uint;
}
}
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