diff --git a/library/std/src/sys/stdio/mod.rs b/library/std/src/sys/stdio/mod.rs index 314f226f07beb..7436e4d9de4da 100644 --- a/library/std/src/sys/stdio/mod.rs +++ b/library/std/src/sys/stdio/mod.rs @@ -29,9 +29,13 @@ cfg_select! { mod uefi; pub use uefi::*; } - target_os = "wasi" => { - mod wasi; - pub use wasi::*; + all(target_os = "wasi", target_env = "p1") => { + mod wasip1; + pub use wasip1::*; + } + all(target_os = "wasi", target_env = "p2") => { + mod wasip2; + pub use wasip2::*; } target_os = "xous" => { mod xous; diff --git a/library/std/src/sys/stdio/wasi.rs b/library/std/src/sys/stdio/wasip1.rs similarity index 100% rename from library/std/src/sys/stdio/wasi.rs rename to library/std/src/sys/stdio/wasip1.rs diff --git a/library/std/src/sys/stdio/wasip2.rs b/library/std/src/sys/stdio/wasip2.rs new file mode 100644 index 0000000000000..1fcb49a083dd0 --- /dev/null +++ b/library/std/src/sys/stdio/wasip2.rs @@ -0,0 +1,120 @@ +use wasip2::cli; +use wasip2::io::streams::{Error, InputStream, OutputStream, StreamError}; + +use crate::io::{self, BorrowedBuf, BorrowedCursor}; + +pub struct Stdin(Option); +pub struct Stdout(Option); +pub struct Stderr(Option); + +fn error_to_io(err: Error) -> io::Error { + // There exists a function in `wasi:filesystem` to optionally acquire an + // error code from an error, but the streams in use in this module are + // exclusively used with stdio meaning that a filesystem error is not + // possible here. + // + // In lieu of an error code, which WASIp2 does not specify, this instead + // carries along the `to_debug_string` implementation that the host + // supplies. If this becomes too expensive in the future this could also + // become `io::Error::from_raw_os_error(libc::EIO)` or similar. + io::Error::new(io::ErrorKind::Other, err.to_debug_string()) +} + +impl Stdin { + pub const fn new() -> Stdin { + Stdin(None) + } + + fn stream(&mut self) -> &InputStream { + self.0.get_or_insert_with(cli::stdin::get_stdin) + } +} + +impl io::Read for Stdin { + fn read(&mut self, data: &mut [u8]) -> io::Result { + let mut buf = BorrowedBuf::from(data); + self.read_buf(buf.unfilled())?; + Ok(buf.len()) + } + + fn read_buf(&mut self, mut buf: BorrowedCursor<'_>) -> io::Result<()> { + match self.stream().blocking_read(u64::try_from(buf.capacity()).unwrap()) { + Ok(result) => { + buf.append(&result); + Ok(()) + } + Err(StreamError::Closed) => Ok(()), + Err(StreamError::LastOperationFailed(e)) => Err(error_to_io(e)), + } + } +} + +impl Stdout { + pub const fn new() -> Stdout { + Stdout(None) + } + + fn stream(&mut self) -> &OutputStream { + self.0.get_or_insert_with(cli::stdout::get_stdout) + } +} + +fn write(stream: &OutputStream, buf: &[u8]) -> io::Result { + // WASIp2's `blocking_write_and_flush` function is defined as accepting no + // more than 4096 bytes. Larger writes can be issued by manually using + // `check_write`, `write`, and `blocking_flush`, but for now just go ahead + // and use `blocking_write_and_flush` and report a short write and let a + // higher level loop over the result. + const MAX: usize = 4096; + let buf = &buf[..buf.len().min(MAX)]; + match stream.blocking_write_and_flush(buf) { + Ok(()) => Ok(buf.len()), + Err(StreamError::Closed) => Ok(0), + Err(StreamError::LastOperationFailed(e)) => Err(error_to_io(e)), + } +} + +impl io::Write for Stdout { + fn write(&mut self, data: &[u8]) -> io::Result { + write(self.stream(), data) + } + + fn flush(&mut self) -> io::Result<()> { + // Note that `OutputStream` has a `flush` function but for stdio all + // writes are accompanied with a flush which means that this flush + // doesn't need to do anything. + Ok(()) + } +} + +impl Stderr { + pub const fn new() -> Stderr { + Stderr(None) + } + + fn stream(&mut self) -> &OutputStream { + self.0.get_or_insert_with(cli::stderr::get_stderr) + } +} + +impl io::Write for Stderr { + fn write(&mut self, data: &[u8]) -> io::Result { + write(self.stream(), data) + } + + fn flush(&mut self) -> io::Result<()> { + // See `Stdout::flush` for why this is a noop. + Ok(()) + } +} + +pub const STDIN_BUF_SIZE: usize = crate::sys::io::DEFAULT_BUF_SIZE; + +pub fn is_ebadf(_err: &io::Error) -> bool { + // WASIp2 stdio streams are always available so ebadf never shows up. + false +} + +pub fn panic_output() -> Option { + Some(Stderr::new()) +}