Import shared_library rust crate

Bug: b/189133061
Test: cd external/rush/crates/shared_library && mm
Change-Id: Ia68e3d776dcef821b1aee02ac2e82a1a1ddd2957

11 files changed, 916 insertions, 0 deletions

diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..13cc0cc
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,48 @@
+// This file is generated by cargo2android.py --run --device --dependencies --tests.
+// Do not modify this file as changes will be overridden on upgrade.
+
+
+
+rust_library {
+    name: "libshared_library",
+    host_supported: true,
+    crate_name: "shared_library",
+    cargo_env_compat: true,
+    cargo_pkg_version: "0.1.9",
+    srcs: ["src/lib.rs"],
+    edition: "2015",
+    rustlibs: [
+        "liblazy_static",
+        "liblibc",
+    ],
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.virt",
+    ],
+}
+
+rust_defaults {
+    name: "shared_library_test_defaults",
+    crate_name: "shared_library",
+    srcs: ["src/lib.rs"],
+    test_suites: ["general-tests"],
+    auto_gen_config: true,
+    edition: "2015",
+    rustlibs: [
+        "liblazy_static",
+        "liblibc",
+    ],
+}
+
+rust_test_host {
+    name: "shared_library_host_test_src_lib",
+    defaults: ["shared_library_test_defaults"],
+    test_options: {
+        unit_test: true,
+    },
+}
+
+rust_test {
+    name: "shared_library_device_test_src_lib",
+    defaults: ["shared_library_test_defaults"],
+}
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..1d7d58b
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,24 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g. crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "shared_library"
+version = "0.1.9"
+authors = ["Pierre Krieger <pierre.krieger1708@gmail.com>"]
+description = "Easily bind to and load shared libraries"
+license = "Apache-2.0/MIT"
+repository = "https://github.com/tomaka/shared_library/"
+[dependencies.lazy_static]
+version = "1"
+
+[dependencies.libc]
+version = "0.2"
diff --git a/Cargo.toml.orig b/Cargo.toml.orig
new file mode 100644
index 0000000..be74698
--- /dev/null
+++ b/Cargo.toml.orig
@@ -0,0 +1,11 @@
+[package]
+name = "shared_library"
+version = "0.1.9"
+authors = ["Pierre Krieger <pierre.krieger1708@gmail.com>"]
+description = "Easily bind to and load shared libraries"
+license = "Apache-2.0/MIT"
+repository = "https://github.com/tomaka/shared_library/"
+
+[dependencies]
+libc = "0.2"
+lazy_static = "1"
diff --git a/LICENSE b/LICENSE
new file mode 120000
index 0000000..6b579aa
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1 @@
+LICENSE-APACHE
\ No newline at end of file
diff --git a/LICENSE-APACHE b/LICENSE-APACHE
new file mode 100644
index 0000000..1b22bef
--- /dev/null
+++ b/LICENSE-APACHE
@@ -0,0 +1,201 @@
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+   Contributor provides its Contributions) on an "AS IS" BASIS,
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+Licensed under the Apache License, Version 2.0 (the "License");
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+Unless required by applicable law or agreed to in writing, software
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diff --git a/LICENSE-MIT b/LICENSE-MIT
new file mode 100644
index 0000000..4f2b149
--- /dev/null
+++ b/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2017 Pierre Krieger
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..0b6518d
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,20 @@
+name: "shared_library"
+description: "Easily bind to and load shared libraries"
+third_party {
+  url {
+    type: HOMEPAGE
+    value: "https://crates.io/crates/shared_library"
+  }
+  url {
+    type: ARCHIVE
+    value: "https://static.crates.io/crates/shared_library/shared_library-0.1.9.crate"
+  }
+  version: "0.1.9"
+  # Dual-licensed, using the least restrictive per go/thirdpartylicenses#same.
+  license_type: NOTICE
+  last_upgrade_date {
+    year: 2021
+    month: 8
+    day: 30
+  }
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..45dc4dd
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+include platform/prebuilts/rust:master:/OWNERS
diff --git a/src/dynamic_library.rs b/src/dynamic_library.rs
new file mode 100644
index 0000000..753b632
--- /dev/null
+++ b/src/dynamic_library.rs
@@ -0,0 +1,410 @@
+// 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
+
+#![allow(missing_docs)]
+
+use std::env;
+use std::ffi::{CString, OsString};
+use std::mem;
+use std::path::{Path, PathBuf};
+use libc;
+
+pub struct DynamicLibrary {
+    handle: *mut u8
+}
+
+unsafe impl Send for DynamicLibrary {}
+unsafe impl Sync for DynamicLibrary {}
+
+impl Drop for DynamicLibrary {
+    fn drop(&mut self) {
+        if let Err(str) = dl::check_for_errors_in(|| unsafe {
+            dl::close(self.handle)
+        }) {
+            panic!("{}", str)
+        }
+    }
+}
+
+/// Special handles to be used with the `symbol_special` function. These are 
+/// provided by a GNU only extension and are not included as part of the POSIX 
+/// standard. 
+///
+/// See https://linux.die.net/man/3/dlsym for their behaviour.
+#[cfg(target_os = "linux")]
+pub enum SpecialHandles {
+    Next,
+    Default,
+}
+
+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 loads the dynamic library named `filename` into memory and 
+    /// then returns an opaque "handle" for that dynamic library.
+    ///
+    /// Returns a handle to the calling process when passed `None`.
+    pub fn open(filename: Option<&Path>) -> Result<Self, String> {
+        // The dynamic library must not be constructed if there is
+        // an error opening the library so the destructor does not
+        // run.
+        dl::open(filename.map(|path| path.as_os_str()))
+            .map(|handle| DynamicLibrary { handle })
+    }
+
+    /// Prepends a path to this process's search path for dynamic libraries
+    pub fn prepend_search_path(path: &Path) {
+        let mut search_path = Self::search_path();
+        search_path.insert(0, path.to_path_buf());
+        env::set_var(Self::envvar(), &Self::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(Self::separator()); }
+            newvar.push(path);
+        }
+        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"
+        }
+    }
+
+    //TODO: turn this and `envvar` into associated constants
+    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(Self::envvar()) {
+            Some(var) => env::split_paths(&var).collect(),
+            None => Vec::new(),
+        }
+    }
+
+    /// Returns the address of where symbol `symbol` was loaded into memory.
+    ///
+    /// In POSIX compliant systems, we return 'Err' if the symbol was not found, 
+    /// in this library or any of the libraries that were automatically loaded 
+    /// when this library was loaded.
+    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();
+        // The value must not be constructed if there is an error so
+        // the destructor does not run.
+        dl::check_for_errors_in(|| {
+                dl::symbol(self.handle as *mut libc::c_void, raw_string.as_ptr() as *const _)
+            })
+            .map(|sym| mem::transmute(sym))
+    }
+
+    /// Returns the address of the first occurance of symbol `symbol` using the 
+    /// default library search order if you use `SpecialHandles::Default`.
+    ///
+    /// Returns the address of the next occurance of symbol `symbol` after the 
+    /// current library in the default library search order if you use 
+    /// `SpecialHandles::Next`.
+    #[cfg(target_os = "linux")]
+    pub unsafe fn symbol_special<T>(handle: SpecialHandles, symbol: &str) -> Result<*mut T, String> {
+        // This function should have a lifetime constraint of 'a on
+        // T but that feature is still unimplemented
+
+        let handle = match handle {
+            SpecialHandles::Next => mem::transmute::<libc::c_long, _>(-1),
+            SpecialHandles::Default => ::std::ptr::null_mut(),
+        };
+
+        let raw_string = CString::new(symbol).unwrap();
+        // The value must not be constructed if there is an error so
+        // the destructor does not run.
+        dl::check_for_errors_in(|| {
+                dl::symbol(handle, raw_string.as_ptr() as *const _)
+            })
+            .map(|sym| mem::transmute(sym))
+    }
+}
+
+#[cfg(all(test, not(target_os = "ios")))]
+mod test {
+    use super::*;
+    use std::mem;
+    use std::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 = "fuchsia",
+              target_os = "netbsd",
+              target_os = "dragonfly",
+              target_os = "bitrig",
+              target_os = "openbsd",
+              target_os = "solaris"))]
+    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.")
+        }
+    }
+}
+
+//TODO: use `unix` shortcut?
+#[cfg(any(target_os = "linux",
+          target_os = "android",
+          target_os = "macos",
+          target_os = "ios",
+          target_os = "fuchsia",
+          target_os = "freebsd",
+          target_os = "netbsd",
+          target_os = "dragonfly",
+          target_os = "bitrig",
+          target_os = "openbsd",
+          target_os = "solaris",
+          target_os = "emscripten"))]
+mod dl {
+    use std::ffi::{CString, CStr, OsStr};
+    use std::os::unix::ffi::OsStrExt;
+    use std::str;
+    use libc;
+    use std::ptr;
+    use std::sync::Mutex;
+
+    lazy_static! {
+        static ref LOCK: Mutex<()> = Mutex::new(());
+    }
+
+    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().to_vec()).unwrap();
+        dlopen(s.as_ptr() as *const _, 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,
+    {
+        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 libc::c_void,
+        symbol: *const libc::c_char,
+    ) -> *mut u8 {
+        dlsym(handle, 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 libc;
+    use std::ops::FnOnce;
+    use std::io::Error as IoError;
+    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;
+
+    pub fn open(filename: Option<&OsStr>) -> Result<*mut u8, String> {
+        // disable "dll load failed" error dialog.
+        let prev_error_mode = unsafe {
+            // SEM_FAILCRITICALERRORS 0x01
+            let new_error_mode = 1;
+            SetErrorMode(new_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() {
+                    Err(format!("{}", IoError::last_os_error()))
+                } else {
+                    Ok(result as *mut u8)
+                }
+            }
+            None => {
+                let mut handle = ptr::null_mut();
+                let succeeded = unsafe {
+                    GetModuleHandleExW(0, ptr::null(), &mut handle)
+                };
+                if succeeded == 0 {
+                    Err(format!("{}", IoError::last_os_error()))
+                } else {
+                    Ok(handle as *mut u8)
+                }
+            }
+        };
+
+        unsafe {
+            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 = IoError::last_os_error();
+            if 0 == error.raw_os_error().unwrap() {
+                Ok(result)
+            } else {
+                Err(format!("{}", error))
+            }
+        }
+    }
+
+    pub unsafe fn symbol(handle: *mut libc::c_void, symbol: *const libc::c_char) -> *mut u8 {
+        GetProcAddress(handle, 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: u32,
+            name: *const u16,
+            handle: *mut *mut libc::c_void,
+        ) -> i32;
+        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;
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..e698a47
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,175 @@
+extern crate libc;
+
+#[macro_use]
+extern crate lazy_static;
+
+pub mod dynamic_library;
+
+/// Error that can happen while loading the shared library.
+#[derive(Debug, Clone)]
+pub enum LoadingError {
+    /// 
+    LibraryNotFound {
+        descr: String,
+    },
+
+    /// One of the symbols could not be found in the library.
+    SymbolNotFound {
+        /// The symbol.
+        symbol: &'static str,
+    }
+}
+
+#[macro_export]
+macro_rules! shared_library {
+    ($struct_name:ident, pub $($rest:tt)+) => {
+        shared_library!(__impl $struct_name [] [] [] pub $($rest)+);
+    };
+
+    ($struct_name:ident, fn $($rest:tt)+) => {
+        shared_library!(__impl $struct_name [] [] [] fn $($rest)+);
+    };
+
+    ($struct_name:ident, static $($rest:tt)+) => {
+        shared_library!(__impl $struct_name [] [] [] static $($rest)+);
+    };
+
+    ($struct_name:ident, $def_path:expr, $($rest:tt)+) => {
+        shared_library!(__impl $struct_name [] [$def_path] [] $($rest)+);
+    };
+
+    (__impl $struct_name:ident
+            [$($p1:tt)*] [$($p2:tt)*] [$($p3:tt)*]
+            , $($rest:tt)*
+    ) => {
+        shared_library!(__impl $struct_name [$($p1)*] [$($p2)*] [$($p3)*] $($rest)*);
+    };
+
+    (__impl $struct_name:ident
+            [$($p1:tt)*] [$($p2:tt)*] [$($p3:tt)*]
+            pub $($rest:tt)*
+    ) => {
+        shared_library!(__impl $struct_name
+                       [$($p1)*] [$($p2)*] [$($p3)* pub] $($rest)*);
+    };
+
+    (__impl $struct_name:ident
+            [$($p1:tt)*] [$($p2:tt)*] [$($p3:tt)*]
+            fn $name:ident($($p:ident:$ty:ty),*) -> $ret:ty, $($rest:tt)*
+    ) => {
+        shared_library!(__impl $struct_name
+                       [$($p1)*, $name:unsafe extern fn($($p:$ty),*) -> $ret]
+                       [$($p2)*]
+                       [$($p3)*
+                           unsafe fn $name($($p:$ty),*) -> $ret {
+                               #![allow(dead_code)]
+                               ($struct_name::get_static_ref().$name)($($p),*)
+                           }
+                        ] $($rest)*);
+    };
+
+    (__impl $struct_name:ident
+            [$($p1:tt)*] [$($p2:tt)*] [$($p3:tt)*]
+            static $name:ident:$ty:ty, $($rest:tt)*
+    ) => {
+        shared_library!(__impl $struct_name
+                       [$($p1)*, $name: $ty]
+                       [$($p2)*]
+                       [$($p3)*] $($rest)*);
+    };
+
+    (__impl $struct_name:ident
+            [$($p1:tt)*] [$($p2:tt)*] [$($p3:tt)*]
+            fn $name:ident($($p:ident:$ty:ty),*), $($rest:tt)*
+    ) => {
+        shared_library!(__impl $struct_name
+                       [$($p1)*] [$($p2)*] [$($p3)*]
+                       fn $name($($p:$ty),*) -> (), $($rest)*);
+    };
+
+    (__impl $struct_name:ident [$(,$mem_n:ident:$mem_t:ty)+] [$($p2:tt)*] [$($p3:tt)*]) => {
+        /// Symbols loaded from a shared library.
+        #[allow(non_snake_case)]
+        pub struct $struct_name {
+            _library_guard: $crate::dynamic_library::DynamicLibrary,
+            $(
+                pub $mem_n: $mem_t,
+            )+
+        }
+
+        impl $struct_name {
+            /// Tries to open the dynamic library.
+            #[allow(non_snake_case)]
+            pub fn open(path: &::std::path::Path) -> Result<$struct_name, $crate::LoadingError> {
+                use std::mem;
+
+                let dylib = match $crate::dynamic_library::DynamicLibrary::open(Some(path)) {
+                    Ok(l) => l,
+                    Err(reason) => return Err($crate::LoadingError::LibraryNotFound { descr: reason })
+                };
+
+                $(
+                    let $mem_n: *mut () = match unsafe { dylib.symbol(stringify!($mem_n)) } {
+                        Ok(s) => s,
+                        Err(_) => return Err($crate::LoadingError::SymbolNotFound { symbol: stringify!($mem_n) }),
+                    };
+                )+
+
+                Ok($struct_name {
+                    _library_guard: dylib,
+                    $(
+                        $mem_n: unsafe { mem::transmute($mem_n) },
+                    )+
+                })
+            }
+        }
+
+        shared_library!(__write_static_fns $struct_name [] [$($p2)*] [$($p3)*]);
+    };
+
+    (__write_static_fns $struct_name:ident [$($p1:tt)*] [] [$($p3:tt)*]) => {
+    };
+
+    (__write_static_fns $struct_name:ident [$($p1:tt)*] [$defpath:expr] [$($standalones:item)+]) => {
+        impl $struct_name {
+            /// This function is used by the regular functions.
+            fn get_static_ref() -> &'static $struct_name {
+                $struct_name::try_loading().ok()
+                                           .expect(concat!("Could not open dynamic \
+                                                            library `", stringify!($struct_name),
+                                                            "`"))
+            }
+
+            /// Try loading the static symbols linked to this library.
+            pub fn try_loading() -> Result<&'static $struct_name, $crate::LoadingError> {
+                use std::sync::{Mutex, Once, ONCE_INIT};
+                use std::mem;
+
+                unsafe {
+                    static mut DATA: *const Mutex<Option<$struct_name>> = 0 as *const _;
+
+                    static mut INIT: Once = ONCE_INIT;
+                    INIT.call_once(|| {
+                        let data = Box::new(Mutex::new(None));
+                        DATA = &*data;
+                        mem::forget(data);
+                    });
+
+                    let data: &Mutex<Option<$struct_name>> = &*DATA;
+                    let mut data = data.lock().unwrap();
+
+                    if let Some(ref data) = *data {
+                        return Ok(mem::transmute(data));
+                    }
+
+                    let path = ::std::path::Path::new($defpath);
+                    let result = try!($struct_name::open(path));
+                    *data = Some(result);
+                    Ok(mem::transmute(data.as_ref().unwrap()))
+                }
+            }
+        }
+
+        $($standalones)+
+    };
+}