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Reduce boilerplate in wasmtime-wasi (#707)

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This commit uses the `*.witx` files describing the current wasi API to
reduce the boilerplate used to define implementations in the
`wasmtime-wasi` crate. Eventually I'd like to remove lots of boilerplate
in the `wasi-common` crate too, but this should at least be a good start!

The boilerplate removed here is:

* No need to list each function to add it to the
  `wasmtime_runtime::Module` being created

* No need to list the signature of the function in a separate
  `syscalls.rs` file.

Instead the `*.witx` file is processed in a single-use macro inside the
`wasmtime-wasi` crate. This macro uses the signatures known from
`*.witx` to automatically register with the right type in the wasm
module as well as define a wrapper that the wasm module will call into.
Functionally this is all the same as before, it's just defined in a
different way now!

The shim generated by this macro which wasmtime calls into only uses
`i32`/`i64`/etc wasm types, and it internally uses `as` casts to convert
to the right wasi types when delegating into the `wasi-common` crate.

One change was necessary to get this implemented, however. The functions
in `wasi-common` sometimes took `WasiCtx` and sometimes took a slice of
memory. After this PR they uniformly all require both `WasiCtx` and
memory so the wrappers can be auto-generated. The arguments are ignored
if they weren't previously required.
This commit is contained in:
Alex Crichton
2019-12-16 16:37:20 -06:00
committed by GitHub
parent c2ba419409
commit cc4be18119
13 changed files with 343 additions and 1067 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
crates/wasi-common/src/fs/dir.rs
View File

@@ -199,7 +199,7 @@ impl<'ctx> Drop for Dir<'ctx> {
// the file descriptor was closed or not, and if we retried (for
// something like EINTR), we might close another valid file descriptor
// opened after we closed ours.
let _ = unsafe { hostcalls::fd_close(self.ctx, self.fd) };
let _ = unsafe { hostcalls::fd_close(self.ctx, &mut [], self.fd) };
}
}

10
crates/wasi-common/src/fs/file.rs
View File

@@ -35,7 +35,7 @@ impl<'ctx> File<'ctx> {
///
/// [`std::fs::File::sync_all`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.sync_all
pub fn sync_all(&self) -> io::Result<()> {
wasi_errno_to_io_error(unsafe { hostcalls::fd_sync(self.ctx, self.fd) })
wasi_errno_to_io_error(unsafe { hostcalls::fd_sync(self.ctx, &mut [], self.fd) })
}
/// This function is similar to `sync_all`, except that it may not synchronize
@@ -45,7 +45,7 @@ impl<'ctx> File<'ctx> {
///
/// [`std::fs::File::sync_data`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.sync_data
pub fn sync_data(&self) -> io::Result<()> {
wasi_errno_to_io_error(unsafe { hostcalls::fd_datasync(self.ctx, self.fd) })
wasi_errno_to_io_error(unsafe { hostcalls::fd_datasync(self.ctx, &mut [], self.fd) })
}
/// Truncates or extends the underlying file, updating the size of this file
@@ -55,7 +55,9 @@ impl<'ctx> File<'ctx> {
///
/// [`std::fs::File::set_len`]: https://doc.rust-lang.org/std/fs/struct.File.html#method.set_len
pub fn set_len(&self, size: u64) -> io::Result<()> {
wasi_errno_to_io_error(unsafe { hostcalls::fd_filestat_set_size(self.ctx, self.fd, size) })
wasi_errno_to_io_error(unsafe {
hostcalls::fd_filestat_set_size(self.ctx, &mut [], self.fd, size)
})
}
/// Queries metadata about the underlying file.
@@ -75,7 +77,7 @@ impl<'ctx> Drop for File<'ctx> {
// the file descriptor was closed or not, and if we retried (for
// something like EINTR), we might close another valid file descriptor
// opened after we closed ours.
let _ = unsafe { hostcalls::fd_close(self.ctx, self.fd) };
let _ = unsafe { hostcalls::fd_close(self.ctx, &mut [], self.fd) };
}
}

13
crates/wasi-common/src/hostcalls/fs.rs
View File

@@ -3,9 +3,9 @@ use crate::ctx::WasiCtx;
use crate::{hostcalls_impl, wasi, wasi32};
hostcalls! {
pub unsafe fn fd_close(wasi_ctx: &mut WasiCtx, fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_close(wasi_ctx: &mut WasiCtx, memory: &mut [u8], fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_datasync(wasi_ctx: &WasiCtx, fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_datasync(wasi_ctx: &WasiCtx, memory: &mut [u8], fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_pread(
wasi_ctx: &WasiCtx,
@@ -38,6 +38,7 @@ hostcalls! {
pub unsafe fn fd_renumber(
wasi_ctx: &mut WasiCtx,
memory: &mut [u8],
from: wasi::__wasi_fd_t,
to: wasi::__wasi_fd_t,
) -> wasi::__wasi_errno_t;
@@ -67,18 +68,20 @@ hostcalls! {
pub unsafe fn fd_fdstat_set_flags(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
fdflags: wasi::__wasi_fdflags_t,
) -> wasi::__wasi_errno_t;
pub unsafe fn fd_fdstat_set_rights(
wasi_ctx: &mut WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
fs_rights_base: wasi::__wasi_rights_t,
fs_rights_inheriting: wasi::__wasi_rights_t,
) -> wasi::__wasi_errno_t;
pub unsafe fn fd_sync(wasi_ctx: &WasiCtx, fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_sync(wasi_ctx: &WasiCtx, memory: &mut [u8], fd: wasi::__wasi_fd_t,) -> wasi::__wasi_errno_t;
pub unsafe fn fd_write(
wasi_ctx: &mut WasiCtx,
@@ -91,6 +94,7 @@ hostcalls! {
pub unsafe fn fd_advise(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
offset: wasi::__wasi_filesize_t,
len: wasi::__wasi_filesize_t,
@@ -99,6 +103,7 @@ hostcalls! {
pub unsafe fn fd_allocate(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
offset: wasi::__wasi_filesize_t,
len: wasi::__wasi_filesize_t,
@@ -179,6 +184,7 @@ hostcalls! {
pub unsafe fn fd_filestat_set_times(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
st_atim: wasi::__wasi_timestamp_t,
st_mtim: wasi::__wasi_timestamp_t,
@@ -187,6 +193,7 @@ hostcalls! {
pub unsafe fn fd_filestat_set_size(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
fd: wasi::__wasi_fd_t,
st_size: wasi::__wasi_filesize_t,
) -> wasi::__wasi_errno_t;

10
crates/wasi-common/src/hostcalls/misc.rs
View File

@@ -5,7 +5,7 @@ use log::trace;
use wasi_common_cbindgen::wasi_common_cbindgen;
#[wasi_common_cbindgen]
pub unsafe fn proc_exit(rval: wasi::__wasi_exitcode_t) {
pub unsafe fn proc_exit(_wasi_ctx: &WasiCtx, _memory: &mut [u8], rval: wasi::__wasi_exitcode_t) {
trace!("proc_exit(rval={:?})", rval);
// TODO: Rather than call std::process::exit here, we should trigger a
// stack unwind similar to a trap.
@@ -51,18 +51,21 @@ hostcalls! {
) -> wasi::__wasi_errno_t;
pub unsafe fn random_get(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
buf_ptr: wasi32::uintptr_t,
buf_len: wasi32::size_t,
) -> wasi::__wasi_errno_t;
pub unsafe fn clock_res_get(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
clock_id: wasi::__wasi_clockid_t,
resolution_ptr: wasi32::uintptr_t,
) -> wasi::__wasi_errno_t;
pub unsafe fn clock_time_get(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
clock_id: wasi::__wasi_clockid_t,
precision: wasi::__wasi_timestamp_t,
@@ -78,5 +81,8 @@ hostcalls! {
nevents: wasi32::uintptr_t,
) -> wasi::__wasi_errno_t;
pub unsafe fn sched_yield() -> wasi::__wasi_errno_t;
pub unsafe fn sched_yield(
wasi_ctx: &WasiCtx,
memory: &mut [u8],
) -> wasi::__wasi_errno_t;
}

25
crates/wasi-common/src/hostcalls_impl/fs.rs
View File

@@ -14,7 +14,11 @@ use std::fs::File;
use std::io::{self, Read, Seek, SeekFrom, Write};
use std::time::{Duration, SystemTime, UNIX_EPOCH};
pub(crate) unsafe fn fd_close(wasi_ctx: &mut WasiCtx, fd: wasi::__wasi_fd_t) -> Result<()> {
pub(crate) unsafe fn fd_close(
wasi_ctx: &mut WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
) -> Result<()> {
trace!("fd_close(fd={:?})", fd);
if let Ok(fe) = wasi_ctx.get_fd_entry(fd) {
@@ -28,7 +32,11 @@ pub(crate) unsafe fn fd_close(wasi_ctx: &mut WasiCtx, fd: wasi::__wasi_fd_t) ->
Ok(())
}
pub(crate) unsafe fn fd_datasync(wasi_ctx: &WasiCtx, fd: wasi::__wasi_fd_t) -> Result<()> {
pub(crate) unsafe fn fd_datasync(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
) -> Result<()> {
trace!("fd_datasync(fd={:?})", fd);
let fd = wasi_ctx
@@ -173,6 +181,7 @@ pub(crate) unsafe fn fd_read(
pub(crate) unsafe fn fd_renumber(
wasi_ctx: &mut WasiCtx,
_memory: &mut [u8],
from: wasi::__wasi_fd_t,
to: wasi::__wasi_fd_t,
) -> Result<()> {
@@ -289,6 +298,7 @@ pub(crate) unsafe fn fd_fdstat_get(
pub(crate) unsafe fn fd_fdstat_set_flags(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
fdflags: wasi::__wasi_fdflags_t,
) -> Result<()> {
@@ -304,6 +314,7 @@ pub(crate) unsafe fn fd_fdstat_set_flags(
pub(crate) unsafe fn fd_fdstat_set_rights(
wasi_ctx: &mut WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
fs_rights_base: wasi::__wasi_rights_t,
fs_rights_inheriting: wasi::__wasi_rights_t,
@@ -327,7 +338,11 @@ pub(crate) unsafe fn fd_fdstat_set_rights(
Ok(())
}
pub(crate) unsafe fn fd_sync(wasi_ctx: &WasiCtx, fd: wasi::__wasi_fd_t) -> Result<()> {
pub(crate) unsafe fn fd_sync(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
) -> Result<()> {
trace!("fd_sync(fd={:?})", fd);
let fd = wasi_ctx
@@ -381,6 +396,7 @@ pub(crate) unsafe fn fd_write(
pub(crate) unsafe fn fd_advise(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
offset: wasi::__wasi_filesize_t,
len: wasi::__wasi_filesize_t,
@@ -404,6 +420,7 @@ pub(crate) unsafe fn fd_advise(
pub(crate) unsafe fn fd_allocate(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
offset: wasi::__wasi_filesize_t,
len: wasi::__wasi_filesize_t,
@@ -687,6 +704,7 @@ pub(crate) unsafe fn fd_filestat_get(
pub(crate) unsafe fn fd_filestat_set_times(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
st_atim: wasi::__wasi_timestamp_t,
st_mtim: wasi::__wasi_timestamp_t,
@@ -746,6 +764,7 @@ pub(crate) fn fd_filestat_set_times_impl(
pub(crate) unsafe fn fd_filestat_set_size(
wasi_ctx: &WasiCtx,
_memory: &mut [u8],
fd: wasi::__wasi_fd_t,
st_size: wasi::__wasi_filesize_t,
) -> Result<()> {

5
crates/wasi-common/src/hostcalls_impl/misc.rs
View File

@@ -128,6 +128,7 @@ pub(crate) fn environ_sizes_get(
}
pub(crate) fn random_get(
_wasi_ctx: &WasiCtx,
memory: &mut [u8],
buf_ptr: wasi32::uintptr_t,
buf_len: wasi32::size_t,
@@ -143,6 +144,7 @@ pub(crate) fn random_get(
}
pub(crate) fn clock_res_get(
_wasi_ctx: &WasiCtx,
memory: &mut [u8],
clock_id: wasi::__wasi_clockid_t,
resolution_ptr: wasi32::uintptr_t,
@@ -161,6 +163,7 @@ pub(crate) fn clock_res_get(
}
pub(crate) fn clock_time_get(
_wasi_ctx: &WasiCtx,
memory: &mut [u8],
clock_id: wasi::__wasi_clockid_t,
precision: wasi::__wasi_timestamp_t,
@@ -180,7 +183,7 @@ pub(crate) fn clock_time_get(
enc_timestamp_byref(memory, time_ptr, time)
}
pub(crate) fn sched_yield() -> Result<()> {
pub(crate) fn sched_yield(_wasi_ctx: &WasiCtx, _memory: &mut [u8]) -> Result<()> {
trace!("sched_yield()");
std::thread::yield_now();