zvariant/
fd.rs

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1use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
2use static_assertions::assert_impl_all;
3use std::os::unix::io;
4
5use crate::{Basic, EncodingFormat, Signature, Type};
6
7/// A [`RawFd`](https://doc.rust-lang.org/std/os/unix/io/type.RawFd.html) wrapper.
8///
9/// See also `OwnedFd` if you need a wrapper that takes ownership of the file.
10///
11/// We wrap the `RawFd` type so that we can implement [`Serialize`] and [`Deserialize`] for it.
12/// File descriptors are serialized in a special way and you need to use specific [serializer] and
13/// [deserializer] API when file descriptors are or could be involved.
14///
15/// [`Serialize`]: https://docs.serde.rs/serde/trait.Serialize.html
16/// [`Deserialize`]: https://docs.serde.rs/serde/de/trait.Deserialize.html
17/// [deserializer]: fn.from_slice_fds.html
18/// [serializer]: fn.to_bytes_fds.html
19#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
20pub struct Fd(io::RawFd);
21
22macro_rules! fd_impl {
23    ($i:ident) => {
24        assert_impl_all!($i: Send, Sync, Unpin);
25
26        impl Basic for $i {
27            const SIGNATURE_CHAR: char = 'h';
28            const SIGNATURE_STR: &'static str = "h";
29
30            fn alignment(format: EncodingFormat) -> usize {
31                u32::alignment(format)
32            }
33        }
34
35        impl Type for $i {
36            fn signature() -> Signature<'static> {
37                Signature::from_static_str_unchecked(Self::SIGNATURE_STR)
38            }
39        }
40    };
41}
42
43fd_impl!(Fd);
44
45impl Serialize for Fd {
46    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
47    where
48        S: Serializer,
49    {
50        serializer.serialize_i32(self.0)
51    }
52}
53
54impl<'de> Deserialize<'de> for Fd {
55    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
56    where
57        D: Deserializer<'de>,
58    {
59        Ok(Fd(i32::deserialize(deserializer)?))
60    }
61}
62
63impl From<io::RawFd> for Fd {
64    fn from(value: io::RawFd) -> Self {
65        Self(value)
66    }
67}
68
69impl<T> From<&T> for Fd
70where
71    T: io::AsRawFd,
72{
73    fn from(t: &T) -> Self {
74        Self(t.as_raw_fd())
75    }
76}
77
78impl io::AsRawFd for Fd {
79    fn as_raw_fd(&self) -> io::RawFd {
80        self.0
81    }
82}
83
84impl std::fmt::Display for Fd {
85    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
86        self.0.fmt(f)
87    }
88}
89
90/// An owned [`RawFd`](https://doc.rust-lang.org/std/os/unix/io/type.RawFd.html) wrapper.
91///
92/// See also [`Fd`]. This type owns the file and will close it on drop. On deserialize, it will
93/// duplicate the file descriptor.
94#[derive(Debug, PartialEq, Eq, Hash)]
95pub struct OwnedFd {
96    inner: io::RawFd,
97}
98
99impl Drop for OwnedFd {
100    fn drop(&mut self) {
101        unsafe {
102            libc::close(self.inner);
103        }
104    }
105}
106
107fd_impl!(OwnedFd);
108
109impl Serialize for OwnedFd {
110    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
111    where
112        S: Serializer,
113    {
114        serializer.serialize_i32(self.inner)
115    }
116}
117
118impl<'de> Deserialize<'de> for OwnedFd {
119    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
120    where
121        D: Deserializer<'de>,
122    {
123        let fd = unsafe { libc::dup(i32::deserialize(deserializer)?) };
124        if fd < 0 {
125            return Err(D::Error::custom(std::io::Error::last_os_error()));
126        }
127        Ok(OwnedFd { inner: fd })
128    }
129}
130
131impl io::FromRawFd for OwnedFd {
132    unsafe fn from_raw_fd(fd: io::RawFd) -> Self {
133        Self { inner: fd }
134    }
135}
136
137impl io::AsRawFd for OwnedFd {
138    fn as_raw_fd(&self) -> io::RawFd {
139        self.inner
140    }
141}
142
143impl io::IntoRawFd for OwnedFd {
144    fn into_raw_fd(self) -> io::RawFd {
145        let fd = self.inner;
146        std::mem::forget(self);
147        fd
148    }
149}
150
151impl std::fmt::Display for OwnedFd {
152    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
153        self.inner.fmt(f)
154    }
155}
zvariant/fd.rs

zvariant/
fd.rs
