Improve unreachable error messages

src/switch.rs

@@ -19,54 +19,54 @@ extern {
 /// Sets current user for the running process, requires root priviledges.
 pub fn set_current_uid(uid: uid_t) -> IOResult<()> {
     match unsafe { setuid(uid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("setuid returned {}", n)
     }
 }
 
 /// Set current group for the running process, requires root priviledges.
 pub fn set_current_gid(gid: gid_t) -> IOResult<()> {
     match unsafe { setgid(gid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("setgid returned {}", n)
     }
 }
 
 /// Set effective user for the running process, requires root priviledges.
 pub fn set_effective_uid(uid: uid_t) -> IOResult<()> {
     match unsafe { seteuid(uid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("seteuid returned {}", n)
     }
 }
 
 /// Set effective user for the running process, requires root priviledges.
 pub fn set_effective_gid(gid: gid_t) -> IOResult<()> {
     match unsafe { setegid(gid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("setegid returned {}", n)
     }
 }
 
 /// Atomically set current and effective user for the running process, requires root priviledges.
 pub fn set_both_uid(ruid: uid_t, euid: uid_t) -> IOResult<()> {
     match unsafe { setreuid(ruid, euid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("setreuid returned {}", n)
     }
 }
 
 /// Atomically set current and effective group for the running process, requires root priviledges.
 pub fn set_both_gid(rgid: gid_t, egid: gid_t) -> IOResult<()> {
     match unsafe { setregid(rgid, egid) } {
-        0 => Ok(()),
+         0 => Ok(()),
         -1 => Err(IOError::last_os_error()),
-        _ => unreachable!()
+         n => unreachable!("setregid returned {}", n)
     }
 }