rustix/
ugid.rs

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 = match owner {
96        Some(o) => o.as_raw(),
97        None => !0,
98    };
99
100    let gr = match group {
101        Some(g) => 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}
rustix/ugid.rs

rustix/
ugid.rs
