Struct BinaryPayload 

pub struct BinaryPayload {
    pub total_bytes_u32be: [u8; 4],
    pub data_type: u8,
    pub _marker: PhantomData<PhantomPinned>,
}

The structure of the “binary message” payload for the PAM_BINARY_PROMPT extension from Linux-PAM.

Fields

total_bytes_u32be: [u8; 4]

The total byte size of the message, including this header, as u32 in network byte order (big endian).

data_type: u8

A tag used to provide some kind of hint as to what the data is. Its meaning is undefined.

_marker: PhantomData<PhantomPinned>

Where the data itself would start, used as a marker to make this not Unpin (since it is effectively an intrusive data structure pointing to immediately after itself).

Implementations

impl BinaryPayload

pub const MAX_SIZE: usize

The most data it’s possible to put into a BinaryPayload.

pub fn fill(buf: &mut [u8], data: &[u8], data_type: u8)

Fills in the provided buffer with the given data.

This uses copy_from_slice internally, so buf must be exactly 5 bytes longer than data, or this function will panic.

pub unsafe fn total_bytes(this: *const Self) -> usize

The total storage needed for the message, including header.

Safety

The pointer must point to a valid BinaryPayload.

pub unsafe fn buffer_of<'a>(ptr: *const Self) -> &'a [u8]

Gets the total byte buffer of the BinaryMessage stored at the pointer.

The returned data slice is borrowed from where the pointer points to.

Safety

• The pointer must point to a valid BinaryPayload.
• The borrowed data must not outlive the pointer’s validity.

pub unsafe fn contents<'a>(ptr: *const Self) -> (&'a [u8], u8)

Gets the contents of the BinaryMessage stored at the given pointer.

The returned data slice is borrowed from where the pointer points to. This is a cheap operation and doesn’t do any copying.

We don’t take a &self reference here because accessing beyond the range of the Self data (i.e., beyond the 5 bytes of self) is undefined behavior. Instead, you have to pass a raw pointer directly to the data.

Safety

• The pointer must point to a valid BinaryPayload.
• The borrowed data must not outlive the pointer’s validity.

pub unsafe fn zero(ptr: *mut Self)

Zeroes out the data of this payload.

Safety

• The pointer must point to a valid BinaryPayload.
• The binary payload must not be used in the future, since its length metadata is gone and so its buffer is unknown.