diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/audioipc2/src/shm.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/audioipc2/src/shm.rs')
-rw-r--r-- | third_party/rust/audioipc2/src/shm.rs | 334 |
1 files changed, 334 insertions, 0 deletions
diff --git a/third_party/rust/audioipc2/src/shm.rs b/third_party/rust/audioipc2/src/shm.rs new file mode 100644 index 0000000000..2aaa92ef36 --- /dev/null +++ b/third_party/rust/audioipc2/src/shm.rs @@ -0,0 +1,334 @@ +// Copyright © 2017 Mozilla Foundation +// +// This program is made available under an ISC-style license. See the +// accompanying file LICENSE for details. + +#![allow(clippy::missing_safety_doc)] + +use crate::errors::*; +use crate::PlatformHandle; +use std::{convert::TryInto, ffi::c_void, slice}; + +#[cfg(unix)] +pub use unix::SharedMem; +#[cfg(windows)] +pub use windows::SharedMem; + +#[derive(Copy, Clone)] +struct SharedMemView { + ptr: *mut c_void, + size: usize, +} + +unsafe impl Send for SharedMemView {} + +impl SharedMemView { + pub unsafe fn get_slice(&self, size: usize) -> Result<&[u8]> { + let map = slice::from_raw_parts(self.ptr as _, self.size); + if size <= self.size { + Ok(&map[..size]) + } else { + bail!("mmap size"); + } + } + + pub unsafe fn get_mut_slice(&mut self, size: usize) -> Result<&mut [u8]> { + let map = slice::from_raw_parts_mut(self.ptr as _, self.size); + if size <= self.size { + Ok(&mut map[..size]) + } else { + bail!("mmap size") + } + } +} + +#[cfg(unix)] +mod unix { + use super::*; + use memmap2::{MmapMut, MmapOptions}; + use std::fs::File; + use std::os::unix::io::{AsRawFd, FromRawFd}; + + #[cfg(target_os = "android")] + fn open_shm_file(_id: &str, size: usize) -> Result<File> { + unsafe { + let fd = ashmem::ASharedMemory_create(std::ptr::null(), size); + if fd >= 0 { + // Drop PROT_EXEC + let r = ashmem::ASharedMemory_setProt(fd, libc::PROT_READ | libc::PROT_WRITE); + assert_eq!(r, 0); + return Ok(File::from_raw_fd(fd.try_into().unwrap())); + } + Err(std::io::Error::last_os_error().into()) + } + } + + #[cfg(not(target_os = "android"))] + fn open_shm_file(id: &str, size: usize) -> Result<File> { + let file = open_shm_file_impl(id)?; + allocate_file(&file, size)?; + Ok(file) + } + + #[cfg(not(target_os = "android"))] + fn open_shm_file_impl(id: &str) -> Result<File> { + use std::env::temp_dir; + use std::fs::{remove_file, OpenOptions}; + + let id_cstring = std::ffi::CString::new(id).unwrap(); + + #[cfg(target_os = "linux")] + { + unsafe { + let r = libc::syscall(libc::SYS_memfd_create, id_cstring.as_ptr(), 0); + if r >= 0 { + return Ok(File::from_raw_fd(r.try_into().unwrap())); + } + } + + let mut path = std::path::PathBuf::from("/dev/shm"); + path.push(id); + + if let Ok(file) = OpenOptions::new() + .read(true) + .write(true) + .create_new(true) + .open(&path) + { + let _ = remove_file(&path); + return Ok(file); + } + } + + unsafe { + let fd = libc::shm_open( + id_cstring.as_ptr(), + libc::O_RDWR | libc::O_CREAT | libc::O_EXCL, + 0o600, + ); + if fd >= 0 { + libc::shm_unlink(id_cstring.as_ptr()); + return Ok(File::from_raw_fd(fd)); + } + } + + let mut path = temp_dir(); + path.push(id); + + let file = OpenOptions::new() + .read(true) + .write(true) + .create_new(true) + .open(&path)?; + + let _ = remove_file(&path); + Ok(file) + } + + #[cfg(not(target_os = "android"))] + fn handle_enospc(s: &str) -> Result<()> { + let err = std::io::Error::last_os_error(); + let errno = err.raw_os_error().unwrap_or(0); + assert_ne!(errno, 0); + debug!("allocate_file: {} failed errno={}", s, errno); + if errno == libc::ENOSPC { + return Err(err.into()); + } + Ok(()) + } + + #[cfg(not(target_os = "android"))] + fn allocate_file(file: &File, size: usize) -> Result<()> { + // First, set the file size. This may create a sparse file on + // many systems, which can fail with SIGBUS when accessed via a + // mapping and the lazy backing allocation fails due to low disk + // space. To avoid this, try to force the entire file to be + // preallocated before mapping using OS-specific approaches below. + + file.set_len(size.try_into().unwrap())?; + + let fd = file.as_raw_fd(); + let size: libc::off_t = size.try_into().unwrap(); + + // Try Linux-specific fallocate. + #[cfg(target_os = "linux")] + { + if unsafe { libc::fallocate(fd, 0, 0, size) } == 0 { + return Ok(()); + } + handle_enospc("fallocate()")?; + } + + // Try macOS-specific fcntl. + #[cfg(target_os = "macos")] + { + let params = libc::fstore_t { + fst_flags: libc::F_ALLOCATEALL, + fst_posmode: libc::F_PEOFPOSMODE, + fst_offset: 0, + fst_length: size, + fst_bytesalloc: 0, + }; + if unsafe { libc::fcntl(fd, libc::F_PREALLOCATE, ¶ms) } == 0 { + return Ok(()); + } + handle_enospc("fcntl(F_PREALLOCATE)")?; + } + + // Fall back to portable version, where available. + #[cfg(any(target_os = "linux", target_os = "freebsd", target_os = "dragonfly"))] + { + if unsafe { libc::posix_fallocate(fd, 0, size) } == 0 { + return Ok(()); + } + handle_enospc("posix_fallocate()")?; + } + + Ok(()) + } + + pub struct SharedMem { + file: File, + _mmap: MmapMut, + view: SharedMemView, + } + + impl SharedMem { + pub fn new(id: &str, size: usize) -> Result<SharedMem> { + let file = open_shm_file(id, size)?; + let mut mmap = unsafe { MmapOptions::new().len(size).map_mut(&file)? }; + assert_eq!(mmap.len(), size); + let view = SharedMemView { + ptr: mmap.as_mut_ptr() as _, + size, + }; + Ok(SharedMem { + file, + _mmap: mmap, + view, + }) + } + + pub unsafe fn make_handle(&self) -> Result<PlatformHandle> { + PlatformHandle::duplicate(self.file.as_raw_fd()).map_err(|e| e.into()) + } + + pub unsafe fn from(handle: PlatformHandle, size: usize) -> Result<SharedMem> { + let file = File::from_raw_fd(handle.into_raw()); + let mut mmap = MmapOptions::new().len(size).map_mut(&file)?; + assert_eq!(mmap.len(), size); + let view = SharedMemView { + ptr: mmap.as_mut_ptr() as _, + size, + }; + Ok(SharedMem { + file, + _mmap: mmap, + view, + }) + } + + pub unsafe fn get_slice(&self, size: usize) -> Result<&[u8]> { + self.view.get_slice(size) + } + + pub unsafe fn get_mut_slice(&mut self, size: usize) -> Result<&mut [u8]> { + self.view.get_mut_slice(size) + } + + pub fn get_size(&self) -> usize { + self.view.size + } + } +} + +#[cfg(windows)] +mod windows { + use super::*; + use std::ptr; + use winapi::{ + shared::{minwindef::DWORD, ntdef::HANDLE}, + um::{ + handleapi::CloseHandle, + memoryapi::{MapViewOfFile, UnmapViewOfFile, FILE_MAP_ALL_ACCESS}, + winbase::CreateFileMappingA, + winnt::PAGE_READWRITE, + }, + }; + + use crate::INVALID_HANDLE_VALUE; + + pub struct SharedMem { + handle: HANDLE, + view: SharedMemView, + } + + unsafe impl Send for SharedMem {} + + impl Drop for SharedMem { + fn drop(&mut self) { + unsafe { + let ok = UnmapViewOfFile(self.view.ptr); + assert_ne!(ok, 0); + let ok = CloseHandle(self.handle); + assert_ne!(ok, 0); + } + } + } + + impl SharedMem { + pub fn new(_id: &str, size: usize) -> Result<SharedMem> { + unsafe { + let handle = CreateFileMappingA( + INVALID_HANDLE_VALUE, + ptr::null_mut(), + PAGE_READWRITE, + (size as u64 >> 32).try_into().unwrap(), + (size as u64 & (DWORD::MAX as u64)).try_into().unwrap(), + ptr::null(), + ); + if handle.is_null() { + return Err(std::io::Error::last_os_error().into()); + } + + let ptr = MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, size); + if ptr.is_null() { + return Err(std::io::Error::last_os_error().into()); + } + + Ok(SharedMem { + handle, + view: SharedMemView { ptr, size }, + }) + } + } + + pub unsafe fn make_handle(&self) -> Result<PlatformHandle> { + PlatformHandle::duplicate(self.handle).map_err(|e| e.into()) + } + + pub unsafe fn from(handle: PlatformHandle, size: usize) -> Result<SharedMem> { + let handle = handle.into_raw(); + let ptr = MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, size); + if ptr.is_null() { + return Err(std::io::Error::last_os_error().into()); + } + Ok(SharedMem { + handle, + view: SharedMemView { ptr, size }, + }) + } + + pub unsafe fn get_slice(&self, size: usize) -> Result<&[u8]> { + self.view.get_slice(size) + } + + pub unsafe fn get_mut_slice(&mut self, size: usize) -> Result<&mut [u8]> { + self.view.get_mut_slice(size) + } + + pub fn get_size(&self) -> usize { + self.view.size + } + } +} |