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

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

//! Type-safe bindings for Zircon object properties.

use crate::{sys, HandleRef, Status};
use std::ops::Deref;
use zerocopy::{FromBytes, Immutable, IntoBytes};

/// Object property types for use with [object_get_property()] and [object_set_property].
#[derive(Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
#[repr(transparent)]
pub struct Property(u32);

impl Deref for Property {
    type Target = u32;

    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

/// A definition for properties about a zircon object.
///
/// # Safety
///
/// `PROPERTY` must correspond to a valid property type and `PropTy` must be the
/// corresponding value type for that property. See
/// https://fuchsia.dev/fuchsia-src/reference/syscalls/object_get_property for a
/// list of available properties and their corresponding value types.
///
/// It must be valid to treat `PropTy` as its corresponding property type and
/// writing the property type to a `PropTy` must completely initialize it. That
/// is, `PropTy` must be "transparent" over the property type.
pub(crate) unsafe trait PropertyQuery {
    /// The raw `Property` value
    const PROPERTY: Property;
    /// The data type of this property
    type PropTy: IntoBytes + FromBytes + Immutable;
}

assoc_values!(Property, [
    NAME = sys::ZX_PROP_NAME;

    #[cfg(target_arch = "x86_64")]
    REGISTER_GS = sys::ZX_PROP_REGISTER_GS;
    #[cfg(target_arch = "x86_64")]
    REGISTER_FS = sys::ZX_PROP_REGISTER_FS;

    PROCESS_BREAK_ON_LOAD = sys::ZX_PROP_PROCESS_BREAK_ON_LOAD;
    PROCESS_DEBUG_ADDR = sys::ZX_PROP_PROCESS_DEBUG_ADDR;
    PROCESS_VDSO_BASE_ADDRESS = sys::ZX_PROP_PROCESS_VDSO_BASE_ADDRESS;
    SOCKET_RX_THRESHOLD = sys::ZX_PROP_SOCKET_RX_THRESHOLD;
    SOCKET_TX_THRESHOLD = sys::ZX_PROP_SOCKET_TX_THRESHOLD;
    CHANNEL_TX_MSG_MAX = sys::ZX_PROP_CHANNEL_TX_MSG_MAX;
    JOB_KILL_ON_OOM = sys::ZX_PROP_JOB_KILL_ON_OOM;
    EXCEPTION_STATE = sys::ZX_PROP_EXCEPTION_STATE;
    VMO_CONTENT_SIZE = sys::ZX_PROP_VMO_CONTENT_SIZE;
    STREAM_MODE_APPEND = sys::ZX_PROP_STREAM_MODE_APPEND;
]);

/// Get a property on a zircon object
pub(crate) fn object_get_property<P: PropertyQuery>(
    handle: HandleRef<'_>,
) -> Result<P::PropTy, Status>
where
    P::PropTy: FromBytes + Immutable,
{
    // this is safe due to the contract on the P::PropTy type in the ObjectProperty trait.
    let mut out = ::std::mem::MaybeUninit::<P::PropTy>::uninit();
    let status = unsafe {
        sys::zx_object_get_property(
            handle.raw_handle(),
            *P::PROPERTY,
            out.as_mut_ptr().cast::<u8>(),
            std::mem::size_of::<P::PropTy>(),
        )
    };
    Status::ok(status).map(|_| unsafe { out.assume_init() })
}

/// Set a property on a zircon object
pub(crate) fn object_set_property<P: PropertyQuery>(
    handle: HandleRef<'_>,
    val: &P::PropTy,
) -> Result<(), Status>
where
    P::PropTy: IntoBytes + Immutable,
{
    let status = unsafe {
        sys::zx_object_set_property(
            handle.raw_handle(),
            *P::PROPERTY,
            std::ptr::from_ref(val).cast::<u8>(),
            std::mem::size_of::<P::PropTy>(),
        )
    };
    Status::ok(status)
}