forked from beerpsi/chuniio-yubideck
220 lines
6.8 KiB
Rust
220 lines
6.8 KiB
Rust
use std::{os::unix::io::RawFd, ptr::null_mut};
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use nix::{
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fcntl::OFlag,
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sys::{
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mman::{mmap, munmap, shm_open, shm_unlink, MapFlags, ProtFlags},
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stat::{fstat, Mode},
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},
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unistd::{close, ftruncate},
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};
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use crate::{log::*, ShmemError};
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#[derive(Clone, Default)]
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pub struct ShmemConfExt;
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pub struct MapData {
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//On linux, you must shm_unlink() the object created for the mapping. It wont disappear automatically.
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owner: bool,
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//File descriptor to our open mapping
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map_fd: RawFd,
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//Shared mapping uid
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pub unique_id: String,
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//Total size of the mapping
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pub map_size: usize,
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//Pointer to the first address of our mapping
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pub map_ptr: *mut u8,
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}
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impl MapData {
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pub fn as_mut_ptr(&self) -> *mut u8 {
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self.map_ptr
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}
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}
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/// Shared memory teardown for linux
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impl Drop for MapData {
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///Takes care of properly closing the SharedMem (munmap(), shmem_unlink(), close())
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fn drop(&mut self) {
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//Unmap memory
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if !self.map_ptr.is_null() {
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trace!(
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"munmap(map_ptr:{:p},map_size:{})",
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self.map_ptr,
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self.map_size
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);
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if let Err(_e) = unsafe { munmap(self.map_ptr as *mut _, self.map_size) } {
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debug!("Failed to munmap() shared memory mapping : {}", _e);
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};
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}
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//Unlink shmem
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if self.map_fd != 0 {
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//unlink shmem if we created it
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if self.owner {
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debug!("Deleting persistent mapping");
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trace!("shm_unlink({})", self.unique_id.as_str());
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if let Err(_e) = shm_unlink(self.unique_id.as_str()) {
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debug!("Failed to shm_unlink() shared memory : {}", _e);
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};
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}
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trace!("close({})", self.map_fd);
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if let Err(_e) = close(self.map_fd) {
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debug!(
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"os_impl::Linux : Failed to close() shared memory file descriptor : {}",
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_e
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);
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};
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}
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}
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}
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impl MapData {
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pub fn set_owner(&mut self, is_owner: bool) -> bool {
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let prev_val = self.owner;
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self.owner = is_owner;
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prev_val
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}
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}
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/// Creates a mapping specified by the uid and size
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pub fn create_mapping(unique_id: &str, map_size: usize) -> Result<MapData, ShmemError> {
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//Create shared memory file descriptor
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debug!("Creating persistent mapping at {}", unique_id);
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let shmem_fd = match shm_open(
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unique_id, //Unique name that usualy pops up in /dev/shm/
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OFlag::O_CREAT | OFlag::O_EXCL | OFlag::O_RDWR, //create exclusively (error if collision) and read/write to allow resize
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Mode::S_IRUSR | Mode::S_IWUSR, //Permission allow user+rw
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) {
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Ok(v) => {
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trace!(
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"shm_open({}, {:X}, {:X}) == {}",
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unique_id,
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OFlag::O_CREAT | OFlag::O_EXCL | OFlag::O_RDWR,
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Mode::S_IRUSR | Mode::S_IWUSR,
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v
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);
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v
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}
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Err(nix::Error::EEXIST) => return Err(ShmemError::MappingIdExists),
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Err(e) => return Err(ShmemError::MapCreateFailed(e as u32)),
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};
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let mut new_map: MapData = MapData {
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owner: true,
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unique_id: String::from(unique_id),
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map_fd: shmem_fd,
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map_size,
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map_ptr: null_mut(),
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};
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//Enlarge the memory descriptor file size to the requested map size
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debug!("Creating memory mapping");
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trace!("ftruncate({}, {})", new_map.map_fd, new_map.map_size);
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match ftruncate(new_map.map_fd, new_map.map_size as _) {
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Ok(_) => {}
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Err(e) => return Err(ShmemError::UnknownOsError(e as u32)),
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};
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//Put the mapping in our address space
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debug!("Loading mapping into address space");
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new_map.map_ptr = match unsafe {
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mmap(
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null_mut(), //Desired addr
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new_map.map_size, //size of mapping
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ProtFlags::PROT_READ | ProtFlags::PROT_WRITE, //Permissions on pages
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MapFlags::MAP_SHARED, //What kind of mapping
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new_map.map_fd, //fd
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0, //Offset into fd
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)
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} {
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Ok(v) => {
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trace!(
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"mmap(NULL, {}, {:X}, {:X}, {}, 0) == {:p}",
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new_map.map_size,
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ProtFlags::PROT_READ | ProtFlags::PROT_WRITE,
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MapFlags::MAP_SHARED,
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new_map.map_fd,
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v
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);
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v as *mut _
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}
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Err(e) => return Err(ShmemError::MapCreateFailed(e as u32)),
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};
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Ok(new_map)
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}
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/// Opens an existing mapping specified by its uid
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pub fn open_mapping(
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unique_id: &str,
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_map_size: usize,
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_ext: &ShmemConfExt,
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) -> Result<MapData, ShmemError> {
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//Open shared memory
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debug!("Openning persistent mapping at {}", unique_id);
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let shmem_fd = match shm_open(
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unique_id,
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OFlag::O_RDWR, //Open read write
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Mode::S_IRUSR,
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) {
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Ok(v) => {
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trace!(
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"shm_open({}, {:X}, {:X}) == {}",
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unique_id,
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OFlag::O_RDWR,
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Mode::S_IRUSR,
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v
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);
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v
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}
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Err(e) => return Err(ShmemError::MapOpenFailed(e as u32)),
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};
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let mut new_map: MapData = MapData {
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owner: false,
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unique_id: String::from(unique_id),
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map_fd: shmem_fd,
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map_size: 0,
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map_ptr: null_mut(),
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};
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//Get mmap size
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new_map.map_size = match fstat(new_map.map_fd) {
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Ok(v) => v.st_size as usize,
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Err(e) => return Err(ShmemError::MapOpenFailed(e as u32)),
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};
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//Map memory into our address space
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debug!("Loading mapping into address space");
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new_map.map_ptr = match unsafe {
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mmap(
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null_mut(), //Desired addr
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new_map.map_size, //size of mapping
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ProtFlags::PROT_READ | ProtFlags::PROT_WRITE, //Permissions on pages
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MapFlags::MAP_SHARED, //What kind of mapping
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new_map.map_fd, //fd
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0, //Offset into fd
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)
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} {
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Ok(v) => {
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trace!(
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"mmap(NULL, {}, {:X}, {:X}, {}, 0) == {:p}",
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new_map.map_size,
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ProtFlags::PROT_READ | ProtFlags::PROT_WRITE,
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MapFlags::MAP_SHARED,
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new_map.map_fd,
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v
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);
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v as *mut _
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}
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Err(e) => return Err(ShmemError::MapOpenFailed(e as u32)),
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};
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Ok(new_map)
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}
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