linux-support 0.0.25

// This file is part of linux-support. It is subject to the license terms in the COPYRIGHT file found in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/linux-support/master/COPYRIGHT. No part of linux-support, including this file, may be copied, modified, propagated, or distributed except according to the terms contained in the COPYRIGHT file.
// Copyright © 2020 The developers of linux-support. See the COPYRIGHT file in the top-level directory of this distribution and at https://raw.githubusercontent.com/lemonrock/linux-support/master/COPYRIGHT.


/// An User Identifier or a Group Identifier.
///
/// Linux uid and gid values can never be negative (unlike, say HP-UX).
pub trait UserOrGroupIdentifier: Sized + Copy + Into<u32> + Default + PartialEq + Eq + PartialOrd + Ord + Hash + FromBytes<Error=ParseNumberError>
{
	/// Zero.
	const Zero: Self;

	/// File name.
	const FileName: &'static str;

	/// Root.
	const root: Self;
	
	/// Current real value (also default).
	fn current_real() -> Self;

	/// Current effective value.
	fn current_effective() -> Self;

	/// `Self::current_real()` will return the uid/gid of the user/group who invoked the program and `Self::current_effective(0` will return the uid/gid of the user/group that owns the executable.
	#[inline(always)]
	fn running_setuid() -> bool
	{
		Self::current_real() != Self::current_effective()
	}

	/// Current real, effective and saved-set values.
	fn current_real_effective_and_saved_set() -> (Self, Self, Self);

	/// Sets the real, effective and saved-set.
	fn set_real_effective_and_saved_set(real: Option<Self>, effective: Option<Self>, saved_set: Option<Self>);

	/// Sets the file system (fs) user or group.
	///
	/// Returns the previous value.
	fn set_file_system(self) -> Self;

	/// Is root user (or group).
	#[inline(always)]
	fn is_root(self) -> bool
	{
		self == Self::root
	}
}