95 lines
2.2 KiB
Rust
95 lines
2.2 KiB
Rust
use std::{
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ffi::c_void,
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io,
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ops::{Deref, DerefMut},
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os::fd::{AsRawFd, FromRawFd, OwnedFd, RawFd},
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ptr::null_mut,
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};
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use crate::sys;
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pub struct SharedMemoryImpl {
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fd: OwnedFd,
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size: usize,
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}
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pub struct FileMappingImpl {
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fd: OwnedFd,
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pointer: *mut c_void,
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size: usize,
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}
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impl sys::SharedMemory for SharedMemoryImpl {
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type Mapping = FileMappingImpl;
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fn map(self) -> io::Result<Self::Mapping> {
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<FileMappingImpl as sys::FileMapping>::map(self.fd, self.size)
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}
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fn new(size: usize) -> io::Result<Self> {
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let fd = unsafe { libc::memfd_create(c"cross-shm".as_ptr(), libc::MFD_CLOEXEC) };
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if fd < 0 {
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return Err(io::Error::last_os_error());
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}
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let fd = unsafe { OwnedFd::from_raw_fd(fd) };
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if unsafe { libc::ftruncate(fd.as_raw_fd(), size as i64) } != 0 {
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return Err(io::Error::last_os_error());
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}
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Ok(Self { fd, size })
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}
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}
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impl AsRawFd for SharedMemoryImpl {
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fn as_raw_fd(&self) -> RawFd {
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self.fd.as_raw_fd()
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}
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}
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impl sys::FileMapping for FileMappingImpl {
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fn map<F: Into<OwnedFd>>(file: F, size: usize) -> io::Result<Self> {
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let fd: OwnedFd = file.into();
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let pointer = unsafe {
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libc::mmap(
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null_mut(),
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size,
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libc::PROT_READ | libc::PROT_WRITE,
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libc::MAP_SHARED,
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fd.as_raw_fd(),
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0,
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)
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};
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if pointer == libc::MAP_FAILED {
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return Err(io::Error::last_os_error());
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}
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Ok(Self { fd, pointer, size })
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}
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}
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impl Drop for FileMappingImpl {
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fn drop(&mut self) {
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unsafe {
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libc::munmap(self.pointer, self.size);
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}
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}
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}
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impl Deref for FileMappingImpl {
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type Target = [u8];
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fn deref(&self) -> &Self::Target {
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unsafe { core::slice::from_raw_parts(self.pointer.cast(), self.size) }
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}
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}
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impl DerefMut for FileMappingImpl {
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fn deref_mut(&mut self) -> &mut Self::Target {
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unsafe { core::slice::from_raw_parts_mut(self.pointer.cast(), self.size) }
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}
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}
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impl AsRawFd for FileMappingImpl {
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fn as_raw_fd(&self) -> RawFd {
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self.fd.as_raw_fd()
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}
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}
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