1//! User and Group ID types.
2
3use crate::backend::c;
4use crate::ffi;
5
6/// A group identifier as a raw integer.
7pub type RawGid = ffi::c_uint;
8/// A user identifier as a raw integer.
9pub type RawUid = ffi::c_uint;
10
11/// `uid_t`—A Unix user ID.
12#[repr(transparent)]
13#[derive(Copy, Clone, Eq, PartialEq, Debug, Hash)]
14pub struct Uid(RawUid);
15
16/// `gid_t`—A Unix group ID.
17#[repr(transparent)]
18#[derive(Copy, Clone, Eq, PartialEq, Debug, Hash)]
19pub struct Gid(RawGid);
20
21impl Uid {
22 /// A `Uid` corresponding to the root user (uid 0).
23 pub const ROOT: Self = Self(0);
24
25 /// Converts a `RawUid` into a `Uid`.
26 ///
27 /// `raw` must be the value of a valid Unix user ID, and not `-1`.
28 #[inline]
29 pub fn from_raw(raw: RawUid) -> Self {
30 debug_assert_ne!(raw, !0);
31 Self(raw)
32 }
33
34 /// Converts a `RawUid` into a `Uid`.
35 ///
36 /// `raw` must be the value of a valid Unix user ID, and not `-1`.
37 #[inline]
38 pub const fn from_raw_unchecked(raw: RawUid) -> Self {
39 Self(raw)
40 }
41
42 /// Converts a `Uid` into a `RawUid`.
43 #[inline]
44 pub const fn as_raw(self) -> RawUid {
45 self.0
46 }
47
48 /// Test whether this uid represents the root user ([`Uid::ROOT`]).
49 #[inline]
50 pub const fn is_root(self) -> bool {
51 self.0 == Self::ROOT.0
52 }
53}
54
55impl Gid {
56 /// A `Gid` corresponding to the root group (gid 0).
57 pub const ROOT: Self = Self(0);
58
59 /// Converts a `RawGid` into a `Gid`.
60 ///
61 /// `raw` must be the value of a valid Unix group ID, and not `-1`.
62 #[inline]
63 pub fn from_raw(raw: RawGid) -> Self {
64 debug_assert_ne!(raw, !0);
65 Self(raw)
66 }
67
68 /// Converts a `RawGid` into a `Gid`.
69 ///
70 /// `raw` must be the value of a valid Unix group ID, and not `-1`.
71 #[inline]
72 pub const fn from_raw_unchecked(raw: RawGid) -> Self {
73 Self(raw)
74 }
75
76 /// Converts a `Gid` into a `RawGid`.
77 #[inline]
78 pub const fn as_raw(self) -> RawGid {
79 self.0
80 }
81
82 /// Test whether this gid represents the root group ([`Gid::ROOT`]).
83 #[inline]
84 pub const fn is_root(self) -> bool {
85 self.0 == Self::ROOT.0
86 }
87}
88
89// Return the raw value of the IDs. In case of `None` it returns `!0` since it
90// has the same bit pattern as `-1` indicating no change to the owner/group ID.
91pub(crate) fn translate_fchown_args(
92 owner: Option<Uid>,
93 group: Option<Gid>,
94) -> (c::uid_t, c::gid_t) {
95 let ow: i32 = match owner {
96 Some(o: Uid) => o.as_raw(),
97 None => !0,
98 };
99
100 let gr: i32 = match group {
101 Some(g: Gid) => g.as_raw(),
102 None => !0,
103 };
104
105 (ow as c::uid_t, gr as c::gid_t)
106}
107
108#[cfg(test)]
109mod tests {
110 use super::*;
111
112 #[test]
113 fn test_sizes() {
114 assert_eq_size!(RawUid, u32);
115 assert_eq_size!(RawGid, u32);
116 assert_eq_size!(RawUid, libc::uid_t);
117 assert_eq_size!(RawGid, libc::gid_t);
118 }
119}
120