lx 0.4.0

A no_std crate to use Linux system calls
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148

use core::{
    marker::PhantomData,
    mem,
};

use crate::{
    ioctl,
    AsRawFd,
};

/// An ioctl's direction.
#[repr(u8)]
pub enum Direction {
    /// The argument is ignored.
    None = 0b00,

    /// This is a write-like operation: the kernel only reads from the argument.
    Write = 0b01,

    /// This is a read-like operation: the kernel only writes to the argument.
    Read = 0b10,

    /// The kernel reads and writes to the argument.
    ReadWrite = 0b11,
}

/// Computes a command number, or request number in a similar way to the `_IO`, `_IOR, `_IOW` and
/// `_IOWR` C macros.
pub const fn cmd(dir: Direction, ty: u8, nr: u8, size: usize) -> u32 {
    if size >> 14 != 0 {
        panic!("size must not exceed 14 bits");
    }
    (nr as u32) | ((ty as u32) << 8) | ((size as u32) << 16) | ((dir as u32) << 30)
}

pub struct None {
    cmd: u32,
}

impl None {
    pub const fn new(ty: u8, nr: u8) -> Self {
        Self {
            cmd: cmd(Direction::None, ty, nr, 0),
        }
    }

    pub const fn cmd(&self) -> u32 {
        self.cmd
    }

    /// Calls the ioctl on a file descriptor.
    ///
    /// # Safety
    ///
    /// This library does know know about the different ioctls. It is up to the caller to ensure
    /// that the ioctl it is making is safe.
    #[inline]
    pub unsafe fn call(&self, fd: &impl AsRawFd) -> crate::Result<i32> {
        ioctl(fd, self.cmd, 0)
    }
}

pub struct Read<T> {
    cmd: u32,
    _marker: PhantomData<*mut T>,
}

impl<T> Read<T> {
    pub const fn new(ty: u8, nr: u8) -> Self {
        Self {
            cmd: cmd(Direction::Read, ty, nr, mem::size_of::<T>()),
            _marker: PhantomData,
        }
    }

    pub const fn cmd(&self) -> u32 {
        self.cmd
    }

    /// Calls the ioctl.
    ///
    /// # Safety
    ///
    /// This library does know know about the different ioctls. It is up to the caller to ensure
    /// that the ioctl it is making is safe.
    #[inline]
    pub unsafe fn call(&self, fd: &impl AsRawFd, t: &mut T) -> crate::Result<i32> {
        ioctl(fd, self.cmd, t as *mut T as usize)
    }
}

pub struct Write<T> {
    cmd: u32,
    _marker: PhantomData<*const T>,
}

impl<T> Write<T> {
    pub const fn new(ty: u8, nr: u8) -> Self {
        Self {
            cmd: cmd(Direction::Write, ty, nr, mem::size_of::<T>()),
            _marker: PhantomData,
        }
    }

    pub const fn cmd(&self) -> u32 {
        self.cmd
    }

    /// Calls the ioctl.
    ///
    /// # Safety
    ///
    /// This library does know know about the different ioctls. It is up to the caller to ensure
    /// that the ioctl it is making is safe.
    #[inline]
    pub unsafe fn call(&self, fd: &impl AsRawFd, t: &T) -> crate::Result<i32> {
        ioctl(fd, self.cmd, t as *const T as usize)
    }
}

pub struct ReadWrite<T> {
    cmd: u32,
    _marker: PhantomData<*mut T>,
}

impl<T> ReadWrite<T> {
    pub const fn new(ty: u8, nr: u8) -> Self {
        Self {
            cmd: cmd(Direction::ReadWrite, ty, nr, mem::size_of::<T>()),
            _marker: PhantomData,
        }
    }

    pub const fn cmd(&self) -> u32 {
        self.cmd
    }

    /// Calls the ioctl.
    ///
    /// # Safety
    ///
    /// This library does know know about the different ioctls. It is up to the caller to ensure
    /// that the ioctl it is making is safe.
    #[inline]
    pub unsafe fn call(&self, fd: &impl AsRawFd, t: &mut T) -> crate::Result<i32> {
        ioctl(fd, self.cmd, t as *mut T as usize)
    }
}