diff options
Diffstat (limited to 'third_party/rust/lucet-wasi-wasmsbx/src/fdentry.rs')
| -rw-r--r-- | third_party/rust/lucet-wasi-wasmsbx/src/fdentry.rs | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/third_party/rust/lucet-wasi-wasmsbx/src/fdentry.rs b/third_party/rust/lucet-wasi-wasmsbx/src/fdentry.rs new file mode 100644 index 0000000000..7c65a64705 --- /dev/null +++ b/third_party/rust/lucet-wasi-wasmsbx/src/fdentry.rs @@ -0,0 +1,169 @@ +use crate::host; +use std::fs::File; +use std::os::unix::prelude::{FileTypeExt, FromRawFd, IntoRawFd, RawFd}; +use std::path::PathBuf; + +#[derive(Debug)] +pub struct FdEntry { + pub fd_object: FdObject, + pub rights_base: host::__wasi_rights_t, + pub rights_inheriting: host::__wasi_rights_t, + pub preopen_path: Option<PathBuf>, +} + +impl FdEntry { + pub fn from_file(file: File) -> FdEntry { + unsafe { FdEntry::from_raw_fd(file.into_raw_fd()) } + } + pub unsafe fn from_raw_fd_for_io_desc(rawfd: RawFd, writable : bool) -> FdEntry { + let (ty, mut rights_base, rights_inheriting) = + ( + host::__WASI_FILETYPE_CHARACTER_DEVICE, + host::RIGHTS_TTY_BASE, + host::RIGHTS_TTY_BASE, + ); + + if !writable { + rights_base &= !host::__WASI_RIGHT_FD_WRITE as host::__wasi_rights_t; + } else { + rights_base &= !host::__WASI_RIGHT_FD_READ as host::__wasi_rights_t; + } + + FdEntry { + fd_object: FdObject { + ty: ty as u8, + rawfd, + needs_close: true, + }, + rights_base, + rights_inheriting, + preopen_path: None, + } + } + +} + +impl FromRawFd for FdEntry { + // TODO: make this a different function with error handling, rather than using the trait method + unsafe fn from_raw_fd(rawfd: RawFd) -> FdEntry { + let (ty, mut rights_base, rights_inheriting) = + determine_type_rights(rawfd).expect("can determine file rights"); + + use nix::fcntl::{fcntl, OFlag, F_GETFL}; + let flags_bits = fcntl(rawfd, F_GETFL).expect("fcntl succeeds"); + let flags = OFlag::from_bits_truncate(flags_bits); + let accmode = flags & OFlag::O_ACCMODE; + if accmode == OFlag::O_RDONLY { + rights_base &= !host::__WASI_RIGHT_FD_WRITE as host::__wasi_rights_t; + } else if accmode == OFlag::O_WRONLY { + rights_base &= !host::__WASI_RIGHT_FD_READ as host::__wasi_rights_t; + } + + FdEntry { + fd_object: FdObject { + ty: ty as u8, + rawfd, + needs_close: true, + }, + rights_base, + rights_inheriting, + preopen_path: None, + } + } +} + +// TODO: can probably make this safe by using fcntl directly rather than going through `File` +pub unsafe fn determine_type_rights( + rawfd: RawFd, +) -> Result< + ( + host::__wasi_filetype_t, + host::__wasi_rights_t, + host::__wasi_rights_t, + ), + host::__wasi_errno_t, +> { + let (ty, rights_base, rights_inheriting) = { + let file = File::from_raw_fd(rawfd); + let ft = file.metadata().unwrap().file_type(); + // we just make a `File` here for convenience; we don't want it to close when it drops + std::mem::forget(file); + if ft.is_block_device() { + ( + host::__WASI_FILETYPE_BLOCK_DEVICE, + host::RIGHTS_BLOCK_DEVICE_BASE, + host::RIGHTS_BLOCK_DEVICE_INHERITING, + ) + } else if ft.is_char_device() { + if nix::unistd::isatty(rawfd).unwrap() { + ( + host::__WASI_FILETYPE_CHARACTER_DEVICE, + host::RIGHTS_TTY_BASE, + host::RIGHTS_TTY_BASE, + ) + } else { + ( + host::__WASI_FILETYPE_CHARACTER_DEVICE, + host::RIGHTS_CHARACTER_DEVICE_BASE, + host::RIGHTS_CHARACTER_DEVICE_INHERITING, + ) + } + } else if ft.is_dir() { + ( + host::__WASI_FILETYPE_DIRECTORY, + host::RIGHTS_DIRECTORY_BASE, + host::RIGHTS_DIRECTORY_INHERITING, + ) + } else if ft.is_file() { + ( + host::__WASI_FILETYPE_REGULAR_FILE, + host::RIGHTS_REGULAR_FILE_BASE, + host::RIGHTS_REGULAR_FILE_INHERITING, + ) + // } else if ft.is_socket() { + // use nix::sys::socket; + // match socket::getsockopt(rawfd, socket::sockopt::SockType).unwrap() { + // socket::SockType::Datagram => ( + // host::__WASI_FILETYPE_SOCKET_DGRAM, + // host::RIGHTS_SOCKET_BASE, + // host::RIGHTS_SOCKET_INHERITING, + // ), + // socket::SockType::Stream => ( + // host::__WASI_FILETYPE_SOCKET_STREAM, + // host::RIGHTS_SOCKET_BASE, + // host::RIGHTS_SOCKET_INHERITING, + // ), + // _ => return Err(host::__WASI_EINVAL as host::__wasi_errno_t), + // } + } else if ft.is_fifo() { + ( + host::__WASI_FILETYPE_SOCKET_STREAM, + host::RIGHTS_SOCKET_BASE, + host::RIGHTS_SOCKET_INHERITING, + ) + } else { + return Err(host::__WASI_EINVAL as host::__wasi_errno_t); + } + }; + Ok(( + ty as host::__wasi_filetype_t, + rights_base, + rights_inheriting, + )) +} + +#[derive(Debug)] +pub struct FdObject { + pub ty: host::__wasi_filetype_t, + pub rawfd: RawFd, + pub needs_close: bool, + // TODO: directories +} + +impl Drop for FdObject { + fn drop(&mut self) { + if self.needs_close { + nix::unistd::close(self.rawfd).unwrap_or_else(|e| eprintln!("FdObject::drop(): {}", e)); + } + } +} |