Struct UserSliceRead 

pub struct UserSliceRead { /* private fields */ }

A validated read-only reference to a user-space memory region.

Construction validates that [ptr, ptr+len) is mapped and readable by the current process. After construction, the kernel can safely read from this region.

Note: The mapping could theoretically be changed by another thread between validation and use. On our single-core kernel this can’t happen because we don’t preempt during a syscall handler (interrupts are re-enabled but the scheduler won’t remove our mappings). For SMP this would need additional protection (e.g. pinning pages).

Implementations

impl UserSliceRead

pub fn new(ptr: u64, len: usize) -> Result<Self, UserSliceError>

Create a new validated read-only user slice.

Fails if:

• ptr is null
• ptr + len overflows or crosses into kernel space
• Any page in the range is not mapped or not user-accessible

pub fn len(&self) -> usize

The length of the validated region in bytes.

pub fn is_empty(&self) -> bool

Whether the region is empty (zero length).

pub fn read_to_vec(&self) -> Vec<u8>

Copy validated user data into a kernel-owned Vec<u8>.

Returns a vector containing a copy of the user memory.

pub fn copy_to(&self, dest: &mut [u8]) -> usize

Copy validated user data into a kernel buffer.

Copies min(self.len, dest.len()) bytes and returns how many were copied.

pub fn read_u8(&self, offset: usize) -> Result<u8, UserSliceError>

Read a single byte from the user slice at the given offset.

pub fn read_u64(&self, offset: usize) -> Result<u64, UserSliceError>

Read a u64 from the user slice at the given offset.

pub fn read_val<T: Copy>(&self) -> Result<T, UserSliceError>

Read a value of type T from the user slice.

Safety

The caller must ensure that T is Pod (plain old data) and that the slice is at least size_of::() bytes.

pub fn as_ptr(&self) -> u64

Get the raw pointer (for logging/debugging only).