Fix calling destructor on uninitialized dynamic library crash.

src/libstd/unstable/dynamic_lib.rs

@@ -31,7 +31,7 @@ impl Drop for DynamicLibrary {
  dl::close(self.handle)
  }
  } {
- Ok(()) => { },
+ Ok(()) => {},
  Err(str) => fail!(str)
  }
  }
@@ -41,14 +41,20 @@ impl DynamicLibrary {
  /// Lazily open a dynamic library. When passed None it gives a
  /// handle to the calling process
  pub fn open(filename: Option<&path::Path>) -> Result<DynamicLibrary, ~str> {
- do dl::check_for_errors_in {
- unsafe {
- DynamicLibrary { handle:
- match filename {
- Some(name) => dl::open_external(name),
- None => dl::open_internal()
- }
+ unsafe {
+ let maybe_library = do dl::check_for_errors_in {
+ match filename {
+ Some(name) => dl::open_external(name),
+ None => dl::open_internal()
  }
+ };
+
+ // 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 })
  }
  }
  }
@@ -58,41 +64,69 @@ impl DynamicLibrary {
  // This function should have a lifetime constraint of 'self on
  // T but that feature is still unimplemented
 
- do dl::check_for_errors_in {
- let symbol_value = do symbol.as_c_str |raw_string| {
+ let maybe_symbol_value = do dl::check_for_errors_in {
+ do symbol.as_c_str |raw_string| {
  dl::symbol(self.handle, raw_string)
- };
+ }
+ };
 
- cast::transmute(symbol_value)
+ // 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(cast::transmute(symbol_value))
  }
  }
 }
 
-#[test]
-#[ignore(cfg(windows))]
-priv 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) => fail!("Could not load self as module: %s", error),
- Ok (libm) => libm
- };
-
- // Unfortunately due to issue #6194 it is not possible to call
- // this as a C function
- let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
- match libm.symbol("cos") {
- Err (error) => fail!("Could not load function cos: %s", error),
- Ok (cosine) => cosine
+
+#[cfg(test)]
+mod test {
+ use super::*;
+ use option::*;
+ use result::*;
+ use path::*;
+ use libc;
+
+ #[test]
+ 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) => fail!("Could not load self as module: %s", error),
+ Ok(libm) => libm
+ };
+
+ // Unfortunately due to issue #6194 it is not possible to call
+ // this as a C function
+ let cosine: extern fn(libc::c_double) -> libc::c_double = unsafe {
+ match libm.symbol("cos") {
+ Err(error) => fail!("Could not load function cos: %s", error),
+ Ok(cosine) => cosine
+ }
+ };
+
+ let argument = 0.0;
+ let expected_result = 1.0;
+ let result = cosine(argument);
+ if result != expected_result {
+ fail!("cos(%?) != %? but equaled %? instead", argument,
+ expected_result, result)
+ }
+ }
+
+ #[test]
+ #[cfg(target_os = "linux")]
+ #[cfg(target_os = "macos")]
+ #[cfg(target_os = "freebsd")]
+ 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 = GenericPath::from_str("/dev/null");
+ match DynamicLibrary::open(Some(&path)) {
+ Err(_) => {}
+ Ok(_) => fail!("Successfully opened the empty library.")
  }
- };
-
- let argument = 0.0;
- let expected_result = 1.0;
- let result = cosine(argument);
- if result != expected_result {
- fail!("cos(%?) != %? but equaled %? instead", argument,
- expected_result, result)
  }
 }