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
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169

//! Some register syscall related types or parameters.

use std::os::unix::io::RawFd;
use std::{fmt, io, mem, ptr};

use crate::sys;

pub(crate) fn execute(
    fd: RawFd,
    opcode: libc::c_uint,
    arg: *const libc::c_void,
    len: libc::c_uint,
) -> io::Result<i32> {
    unsafe {
        let ret = sys::io_uring_register(fd, opcode, arg, len);
        if ret >= 0 {
            Ok(ret)
        } else {
            Err(io::Error::last_os_error())
        }
    }
}

/// Information about what `io_uring` features the kernel supports.
///
/// You can fill this in with [`register_probe`](crate::Submitter::register_probe).
pub struct Probe(ptr::NonNull<sys::io_uring_probe>);

impl Probe {
    pub(crate) const COUNT: usize = 256;
    pub(crate) const SIZE: usize = mem::size_of::<sys::io_uring_probe>()
        + Self::COUNT * mem::size_of::<sys::io_uring_probe_op>();

    /// Create a new probe with no features enabled.
    #[allow(clippy::cast_ptr_alignment)]
    pub fn new() -> Probe {
        use std::alloc::{alloc_zeroed, Layout};

        let probe_align = Layout::new::<sys::io_uring_probe>().align();
        let ptr = unsafe {
            let probe_layout = Layout::from_size_align_unchecked(Probe::SIZE, probe_align);
            alloc_zeroed(probe_layout)
        };

        ptr::NonNull::new(ptr)
            .map(ptr::NonNull::cast)
            .map(Probe)
            .expect("Probe alloc failed!")
    }

    #[inline]
    pub(crate) fn as_mut_ptr(&mut self) -> *mut sys::io_uring_probe {
        self.0.as_ptr()
    }

    /// Get whether a specific opcode is supported.
    pub fn is_supported(&self, opcode: u8) -> bool {
        unsafe {
            let probe = &*self.0.as_ptr();

            if opcode <= probe.last_op {
                let ops = probe.ops.as_slice(Self::COUNT);
                ops[opcode as usize].flags & (sys::IO_URING_OP_SUPPORTED as u16) != 0
            } else {
                false
            }
        }
    }
}

impl Default for Probe {
    #[inline]
    fn default() -> Probe {
        Probe::new()
    }
}

impl fmt::Debug for Probe {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        struct Op(sys::io_uring_probe_op);

        impl fmt::Debug for Op {
            #[inline]
            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
                f.debug_struct("Op").field("code", &self.0.op).finish()
            }
        }

        let probe = unsafe { &*self.0.as_ptr() };
        let list = unsafe { probe.ops.as_slice(probe.last_op as usize + 1) };
        let list = list
            .iter()
            .filter(|op| op.flags & (sys::IO_URING_OP_SUPPORTED as u16) != 0)
            .map(|&op| Op(op));

        f.debug_set().entries(list).finish()
    }
}

impl Drop for Probe {
    fn drop(&mut self) {
        use std::alloc::{dealloc, Layout};

        let probe_align = Layout::new::<sys::io_uring_probe>().align();
        unsafe {
            let probe_layout = Layout::from_size_align_unchecked(Probe::SIZE, probe_align);
            dealloc(self.0.as_ptr() as *mut _, probe_layout);
        }
    }
}

/// An allowed feature of io_uring. You can set the allowed features with
/// [`register_restrictions`](crate::Submitter::register_restrictions).
///
/// Requires the `unstable` feature.
#[cfg(feature = "unstable")]
#[repr(transparent)]
pub struct Restriction(sys::io_uring_restriction);

/// inline zeroed to improve codegen
#[cfg(feature = "unstable")]
#[inline(always)]
fn res_zeroed() -> sys::io_uring_restriction {
    unsafe { std::mem::zeroed() }
}

#[cfg(feature = "unstable")]
impl Restriction {
    /// Allow an `io_uring_register` opcode.
    pub fn register_op(op: u8) -> Restriction {
        let mut res = res_zeroed();
        res.opcode = sys::IORING_RESTRICTION_REGISTER_OP as _;
        res.__bindgen_anon_1.register_op = op;
        Restriction(res)
    }

    /// Allow a submission queue event opcode.
    pub fn sqe_op(op: u8) -> Restriction {
        let mut res = res_zeroed();
        res.opcode = sys::IORING_RESTRICTION_SQE_OP as _;
        res.__bindgen_anon_1.sqe_op = op;
        Restriction(res)
    }

    /// Allow the given [submission queue event flags](crate::squeue::Flags).
    pub fn sqe_flags_allowed(flags: u8) -> Restriction {
        let mut res = res_zeroed();
        res.opcode = sys::IORING_RESTRICTION_SQE_FLAGS_ALLOWED as _;
        res.__bindgen_anon_1.sqe_flags = flags;
        Restriction(res)
    }

    /// Require the given [submission queue event flags](crate::squeue::Flags). These flags must be
    /// set on every submission.
    pub fn sqe_flags_required(flags: u8) -> Restriction {
        let mut res = res_zeroed();
        res.opcode = sys::IORING_RESTRICTION_SQE_FLAGS_REQUIRED as _;
        res.__bindgen_anon_1.sqe_flags = flags;
        Restriction(res)
    }
}

/// A RawFd, which can be used for
/// [register_files_update](crate::Submitter::register_files_update).
///
/// File descriptors can be skipped if they are set to `SKIP_FILE`.
/// Skipping an fd will not touch the file associated with the previous fd at that index.
#[cfg(feature = "unstable")]
pub const SKIP_FILE: RawFd = sys::IORING_REGISTER_FILES_SKIP;