getopt.rs(3): fixed pointer shenanigans

src/getopt.rs

@@ -16,7 +16,7 @@
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
 
-use std::ffi::{ c_int, c_char, CString };
+use std::ffi::{ c_int, c_char, CString, CStr };
 
 pub struct Opt {
 	pub arg: Option<String>,
@@ -36,19 +36,21 @@ pub trait GetOpt {
 
 impl GetOpt for Vec<String> {
     fn getopt(&self, optstring: &str) -> Option<Result<Opt, OptError>> {
-		let argv = self
+        let c_strings: Vec<_> = self
 			.iter()
 			.cloned()
 			.map(CString::new)
 			.map(Result::unwrap)
-			.map(|x| x.as_ptr() as c_char)
-			.collect::<Vec<c_char>>()
-			.as_ptr() as *const *mut c_char;
-		let opts = CString::new(optstring).unwrap().into_raw();
+			.collect();
+
+        let argv: Vec<_> = c_strings.iter().map(|x| x.as_ptr()).collect();
+        let argv_ptr = argv.as_ptr() as *const *mut c_char;
+        let optstring_c = CString::new(optstring).unwrap();
+        let opts = optstring_c.into_raw();
         let len = self.len() as c_int;
 
         unsafe {
-			let a = match getopt(len, argv, opts) {
+            let a = match getopt(len, argv_ptr, opts) {
 				/* From getopt(3p):
 				 *
 				 * The getopt() function shall return the next option character
@@ -65,11 +67,11 @@ impl GetOpt for Vec<String> {
 				 *
 				 * Otherwise, getopt() shall return -1 when all command line
 				 * options are parsed. */
-				58 => { // ASCII value for ':'
+                58 => { /* ASCII value for ':' */
 					return Some(Err(OptError::MissingArg));
 				},
-				63 => { // ASCII value for '?'
-					return Some(Err(OptError::UnknownOpt));
+                63 => { /* ASCII value for '?' */
+					return Some(Err(OptError::UnknownOpt))
 				},
 				/* From getopt(3p):
 				 *
@@ -85,17 +87,16 @@ impl GetOpt for Vec<String> {
 				 *
 				 * getopt() shall return -1 after incrementing optind. */
                 -1 => return None,
-				a => a.to_string(),
+                _ => CStr::from_ptr(optarg).to_string_lossy().into_owned(),
             };
 
             Some(Ok(Opt { arg: Some(a), ind: optind, opt: optopt }))
         }
     }
 }
-
 /* binding to getopt(3p) */
 extern "C" {
-	static mut _optarg: *mut c_char;
+	static mut optarg: *mut c_char;
 	static mut _opterr: c_int;
 	static mut optind: c_int;
 	static mut optopt: c_int;