Struct Mapping 

pub struct Mapping { /* private fields */ }

Describes a single memory mapping entry.

The size of this type heavily influences Starnix’s heap usage in common scenarios, please think twice about increasing its size. Compiling in “release” mode includes a compile time check for size increase.

Implementations

impl Mapping

pub fn name(&self) -> MappingNameRef<'_>

pub fn set_name(&mut self, new: MappingName)

impl Mapping

pub fn new( backing: MappingBacking, flags: MappingFlags, mode: MappingMode, ) -> Mapping

pub fn with_name( backing: MappingBacking, flags: MappingFlags, name: MappingName, mode: MappingMode, ) -> Mapping

pub fn flags(&self) -> MappingFlags

pub fn mapping_mode(&self) -> MappingMode

pub fn set_mapping_mode(&mut self, mode: MappingMode)

pub fn set_flags(&mut self, new_flags: MappingFlags)

pub fn get_backing_internal(&self) -> &MappingBacking

pub fn set_backing_internal(&mut self, backing: MappingBacking)

pub fn set_uffd(&mut self, mode: FaultRegisterMode)

pub fn clear_uffd(&mut self)

pub fn set_mlock(&mut self)

pub fn clear_mlock(&mut self)

pub fn new_private_anonymous( flags: MappingFlags, name: MappingName, mode: MappingMode, ) -> Mapping

pub fn inflate_to_include_guard_pages( &self, range: &Range<UserAddress>, ) -> Range<UserAddress>

pub fn address_to_offset(&self, addr: UserAddress) -> u64

Converts a UserAddress to an offset in this mapping’s memory object.

pub fn can_read(&self) -> bool

pub fn can_write(&self) -> bool

pub fn can_exec(&self) -> bool

pub fn may_exec(&self) -> bool

Returns whether this mapping is allowed to be executable, as reported by me in /proc/[pid]/smaps. For file mappings, this is false if the file is on a noexec mount or is sealed against execution. Security checks (see security::file_mprotect()) may still deny making the mapping executable.

pub fn is_private_file(&self) -> bool

Returns whether this is a private mapping of a file (as opposed to a MAP_SHARED mapping or an anonymous mapping).

Unlike MAP_SHARED and anonymous mappings (which access their backing pages directly), writes to a private file mapping perform copy-on-write against the underlying file VMO. MappingFlags::ANONYMOUS must also be checked because some anonymous mappings (such as mmap of /dev/zero) carry MappingName::File for /proc/<pid>/maps display while setting MappingFlags::ANONYMOUS.

pub fn is_unmodified_private_file(&self) -> bool

Returns whether this is a private file mapping that is not yet recorded as holding pages modified via copy-on-write.

pub fn has_cow_modifications(&self) -> bool

Returns whether this is a private file mapping with pages that were modified via copy-on-write, and are therefore no longer shared with the mapped file.

Copy-on-write modifications are tracked at the granularity of the backing MemoryObject (and synchronized across all mappings sharing that backing memory when write access is enabled), rather than per-page.

pub fn set_cow_modified(&mut self)

Records that the memory of this mapping holds pages modified via copy-on-write. See Mapping::has_cow_modifications.

pub fn vmar_flags(&self) -> MappingFlags

Returns the MappingFlags to apply in the user VMAR when mapping or restoring permissions on populated pages of this mapping.

For writable private file mappings, MappingFlags::WRITE is omitted while the mapping is unmodified (both when initially mapped and across any subsequent VMAR remaps or protection updates) so that the first write faults. Once a write is recorded with Mapping::set_cow_modified, vmar_flags() includes MappingFlags::WRITE.

Note that userfaultfd (MappingFlags::UFFD) strips VMAR permissions separately on unpopulated pages via UserFault, and uses vmar_flags() when restoring permissions on populated or unregistered ranges.

pub fn private_anonymous(&self) -> bool

pub fn write_vm_flags(&self, sink: &mut DynamicFileBuf)

Trait Implementations

impl Clone for Mapping

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Mapping

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for Mapping

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.

impl Eq for Mapping

impl PartialEq for Mapping

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.