Return Result<String, String> from getusername

src/whoami/platform/unix.rs

@@ -16,9 +16,10 @@ extern {
     pub fn geteuid() -> libc::uid_t;
 }
 
-pub unsafe fn getusername() -> String {
+pub unsafe fn getusername() -> Result<String, String> {
     let passwd: *const c_passwd = getpwuid(geteuid());
 
     let pw_name: *const libc::c_char = (*passwd).pw_name;
-    String::from_utf8_lossy(::std::ffi::CStr::from_ptr(pw_name).to_bytes()).to_string()
+    let username = String::from_utf8_lossy(::std::ffi::CStr::from_ptr(pw_name).to_bytes()).to_string();
+    Ok(username)
 }

src/whoami/platform/windows.rs

@@ -18,11 +18,12 @@ use std::ffi::OsString;
 use std::os::windows::ffi::OsStringExt;
 use self::wide::FromWide;
 
-pub unsafe fn getusername() -> String {
+pub unsafe fn getusername() -> Result<String, String> {
     let mut buffer: [winapi::WCHAR; winapi::UNLEN as usize + 1] = mem::uninitialized();
     let mut len = buffer.len() as winapi::DWORD;
     if advapi32::GetUserNameW(buffer.as_mut_ptr(), &mut len) == 0 {
-        crash!(1, "failed to get username");
+        return Err("failed to get username".to_string())
     }
-    String::from_wide(&buffer[..len as usize - 1])
+    let username = String::from_wide(&buffer[..len as usize - 1]);
+    Ok(username)
 }

src/whoami/whoami.rs

@@ -54,7 +54,9 @@ pub fn uumain(args: Vec<String>) -> i32 {
 
 pub fn exec() {
     unsafe {
-        let username = platform::getusername();
-        println!("{}", username);
+        match platform::getusername() {
+            Ok(username) => println!("{}", username),
+            Err(msg) => crash!(libc::EXIT_FAILURE, "{}", msg),
+        }
     }
 }