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e0b1193361
This is intended to a Rust analog to "src/util", which has
many utilities used by Mesa developers. This is mostly
a copy of ${crosvm} rutabaga_gfx/src/rutabaga_os (which will
be deleted in favor of this crate).
Key constructs include:
- SharedMemory
- MemoryMapping
- Tube (sockets, essentially)
- OwnedDescriptor (HANDLE or fd-based)
- WaitContext (epoll, ..)
As one would expect, Linux implementations are the most complete.
Acked-by: Aaron Ruby <aruby@qnx.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35210>
62 lines
1.7 KiB
Rust
62 lines
1.7 KiB
Rust
// Copyright 2025 Google
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// SPDX-License-Identifier: MIT
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use std::ffi::CStr;
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use std::os::fd::AsRawFd;
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use std::os::fd::IntoRawFd;
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use std::os::unix::io::OwnedFd;
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use rustix::fs::ftruncate;
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use rustix::fs::memfd_create;
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use rustix::fs::MemfdFlags;
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use crate::descriptor::AsRawDescriptor;
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use crate::descriptor::IntoRawDescriptor;
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use crate::MesaResult;
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use crate::RawDescriptor;
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pub struct SharedMemory {
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fd: OwnedFd,
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size: u64,
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}
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impl SharedMemory {
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/// Creates a new shared memory file descriptor with zero size.
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///
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/// If a name is given, it will appear in `/proc/self/fd/<shm fd>` for the purposes of
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/// debugging. The name does not need to be unique.
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///
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/// The file descriptor is opened with the close on exec flag and allows memfd sealing.
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pub fn new(debug_name: &CStr, size: u64) -> MesaResult<SharedMemory> {
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let fd = memfd_create(debug_name, MemfdFlags::CLOEXEC | MemfdFlags::ALLOW_SEALING)?;
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ftruncate(&fd, size)?;
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Ok(SharedMemory { fd, size })
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}
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/// Gets the size in bytes of the shared memory.
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///
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/// The size returned here does not reflect changes by other interfaces or users of the shared
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/// memory file descriptor..
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pub fn size(&self) -> u64 {
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self.size
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}
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}
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impl AsRawDescriptor for SharedMemory {
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fn as_raw_descriptor(&self) -> RawDescriptor {
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self.fd.as_raw_fd()
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}
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}
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impl IntoRawDescriptor for SharedMemory {
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fn into_raw_descriptor(self) -> RawDescriptor {
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self.fd.into_raw_fd()
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}
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}
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pub fn page_size() -> MesaResult<u64> {
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// TODO: Once all platforms support it, use rustix page_size() function everywhere.
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Ok(rustix::param::page_size() as _)
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}
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