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[wasi-common]: clean up error handling (#1253)

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* Introduce WasiCtxBuilderError error type

`WasiCtxBuilderError` is the `wasi-common` client-facing error type
which is exclusively thrown when building a new `WasiCtx` instance.
As such, building such an instance should not require the client to
understand different WASI errno values as was assumed until now.

This commit is a first step at streamlining error handling in
`wasi-common` and makes way for the `wiggle` crate.

When adding the `WasiCtxBuilderError`, I've had to do two things of
notable importance:
1. I've removed a couple of `ok_or` calls in `WasiCtxBuilder::build`
   and replaced them with `unwrap`s, following the same pattern in
   different builder methods above. This is fine since we _always_
   operate on non-empty `Option`s in `WasiCtxBuilder` thus `unwrap`ing
   will never fail. On the other hand, this might be a good opportunity
   to rethink the structure of our builder, and how we good remove
   the said `Option`s especially since we always populate them with
   empty containers to begin with. I understand this is to make
   chaining of builder methods easier which take and return `&mut self`
   and the same applies to `WasiCtxBuilder::build(&mut self)` method,
   but perhaps it would more cleanly signal the intentions if we simply
   moved `WasiCtxBuilder` instance around. Food for thought!
2. Methods specific to determining rights of passed around `std::fs::File`
   objects when populating `WasiCtx` `FdEntry` entities now return
   `io::Error` directly so that we can reuse them in `WasiCtxBuilder` methods
   (returning `WasiCtxBuilderError` error type), and in syscalls
   (returning WASI errno).

* Return WasiError directly in syscalls

Also, removes `error::Error` type altogether. Now, `io::Error` and
related are automatically converted to their corresponding WASI
errno value encapsulated as `WasiError`.

While here, it made sense to me to move `WasiError` to `wasi` module
which will align itself well with the upcoming changes introduced
by `wiggle`. To different standard `Result` from WASI specific, I've
created a helper alias `WasiResult` also residing in `wasi` module.

* Update wig

* Add from ffi::NulError and pass context to NotADirectory

* Add dummy commit to test CI
This commit is contained in:
Jakub Konka
2020-03-09 22:58:55 +01:00
committed by GitHub
parent 963bf0e255
commit 773915b4bf
59 changed files with 1465 additions and 1552 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
crates/wasi-common/src/hostcalls_impl/misc.rs
View File

@@ -3,7 +3,8 @@ use crate::ctx::WasiCtx;
use crate::fdentry::Descriptor;
use crate::memory::*;
use crate::sys::hostcalls_impl;
use crate::{wasi, wasi32, Error, Result};
use crate::wasi::{self, WasiError, WasiResult};
use crate::wasi32;
use log::{error, trace};
use std::convert::TryFrom;
@@ -12,7 +13,7 @@ pub(crate) fn args_get(
memory: &mut [u8],
argv_ptr: wasi32::uintptr_t,
argv_buf: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"args_get(argv_ptr={:#x?}, argv_buf={:#x?})",
argv_ptr,
@@ -31,7 +32,9 @@ pub(crate) fn args_get(
argv.push(arg_ptr);
let len = wasi32::uintptr_t::try_from(arg_bytes.len())?;
argv_buf_offset = argv_buf_offset.checked_add(len).ok_or(Error::EOVERFLOW)?;
argv_buf_offset = argv_buf_offset
.checked_add(len)
.ok_or(WasiError::EOVERFLOW)?;
}
enc_slice_of_wasi32_uintptr(memory, argv.as_slice(), argv_ptr)
@@ -42,7 +45,7 @@ pub(crate) fn args_sizes_get(
memory: &mut [u8],
argc_ptr: wasi32::uintptr_t,
argv_buf_size_ptr: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"args_sizes_get(argc_ptr={:#x?}, argv_buf_size_ptr={:#x?})",
argc_ptr,
@@ -70,7 +73,7 @@ pub(crate) fn environ_get(
memory: &mut [u8],
environ_ptr: wasi32::uintptr_t,
environ_buf: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"environ_get(environ_ptr={:#x?}, environ_buf={:#x?})",
environ_ptr,
@@ -91,7 +94,7 @@ pub(crate) fn environ_get(
let len = wasi32::uintptr_t::try_from(env_bytes.len())?;
environ_buf_offset = environ_buf_offset
.checked_add(len)
.ok_or(Error::EOVERFLOW)?;
.ok_or(WasiError::EOVERFLOW)?;
}
enc_slice_of_wasi32_uintptr(memory, environ.as_slice(), environ_ptr)
@@ -102,7 +105,7 @@ pub(crate) fn environ_sizes_get(
memory: &mut [u8],
environ_count_ptr: wasi32::uintptr_t,
environ_size_ptr: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"environ_sizes_get(environ_count_ptr={:#x?}, environ_size_ptr={:#x?})",
environ_count_ptr,
@@ -116,7 +119,7 @@ pub(crate) fn environ_sizes_get(
.try_fold(0, |acc: u32, pair| {
acc.checked_add(pair.as_bytes_with_nul().len() as u32)
})
.ok_or(Error::EOVERFLOW)?;
.ok_or(WasiError::EOVERFLOW)?;
trace!(" | *environ_count_ptr={:?}", environ_count);
@@ -132,14 +135,14 @@ pub(crate) fn random_get(
memory: &mut [u8],
buf_ptr: wasi32::uintptr_t,
buf_len: wasi32::size_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!("random_get(buf_ptr={:#x?}, buf_len={:?})", buf_ptr, buf_len);
let buf = dec_slice_of_mut_u8(memory, buf_ptr, buf_len)?;
getrandom::getrandom(buf).map_err(|err| {
error!("getrandom failure: {:?}", err);
Error::EIO
WasiError::EIO
})
}
@@ -148,7 +151,7 @@ pub(crate) fn clock_res_get(
memory: &mut [u8],
clock_id: wasi::__wasi_clockid_t,
resolution_ptr: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"clock_res_get(clock_id={:?}, resolution_ptr={:#x?})",
clock_id,
@@ -168,7 +171,7 @@ pub(crate) fn clock_time_get(
clock_id: wasi::__wasi_clockid_t,
precision: wasi::__wasi_timestamp_t,
time_ptr: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"clock_time_get(clock_id={:?}, precision={:?}, time_ptr={:#x?})",
clock_id,
@@ -183,7 +186,7 @@ pub(crate) fn clock_time_get(
enc_timestamp_byref(memory, time_ptr, time)
}
pub(crate) fn sched_yield(_wasi_ctx: &WasiCtx, _memory: &mut [u8]) -> Result<()> {
pub(crate) fn sched_yield(_wasi_ctx: &WasiCtx, _memory: &mut [u8]) -> WasiResult<()> {
trace!("sched_yield()");
std::thread::yield_now();
@@ -198,7 +201,7 @@ pub(crate) fn poll_oneoff(
output: wasi32::uintptr_t,
nsubscriptions: wasi32::size_t,
nevents: wasi32::uintptr_t,
) -> Result<()> {
) -> WasiResult<()> {
trace!(
"poll_oneoff(input={:#x?}, output={:#x?}, nsubscriptions={}, nevents={:#x?})",
input,
@@ -208,7 +211,7 @@ pub(crate) fn poll_oneoff(
);
if u64::from(nsubscriptions) > wasi::__wasi_filesize_t::max_value() {
return Err(Error::EINVAL);
return Err(WasiError::EINVAL);
}
enc_int_byref(memory, nevents, 0)?;
@@ -222,7 +225,7 @@ pub(crate) fn poll_oneoff(
// As mandated by the WASI spec:
// > If `nsubscriptions` is 0, returns `errno::inval`.
if subscriptions.is_empty() {
return Err(Error::EINVAL);
return Err(WasiError::EINVAL);
}
for subscription in subscriptions {
match subscription.u.tag {
@@ -258,7 +261,7 @@ pub(crate) fn poll_oneoff(
Err(err) => {
let event = wasi::__wasi_event_t {
userdata: subscription.userdata,
error: err.as_wasi_error().as_raw_errno(),
error: err.as_raw_errno(),
r#type: wasi::__WASI_EVENTTYPE_FD_READ,
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
@@ -286,7 +289,7 @@ pub(crate) fn poll_oneoff(
Err(err) => {
let event = wasi::__wasi_event_t {
userdata: subscription.userdata,
error: err.as_wasi_error().as_raw_errno(),
error: err.as_raw_errno(),
r#type: wasi::__WASI_EVENTTYPE_FD_WRITE,
fd_readwrite: wasi::__wasi_event_fd_readwrite_t {
nbytes: 0,
@@ -310,7 +313,7 @@ pub(crate) fn poll_oneoff(
// events have been filtered out as errors in the code above.
hostcalls_impl::poll_oneoff(timeout, fd_events, &mut events)?;
let events_count = u32::try_from(events.len()).map_err(|_| Error::EOVERFLOW)?;
let events_count = u32::try_from(events.len()).map_err(|_| WasiError::EOVERFLOW)?;
enc_events(memory, output, nsubscriptions, events)?;
@@ -319,7 +322,9 @@ pub(crate) fn poll_oneoff(
enc_int_byref(memory, nevents, events_count)
}
fn wasi_clock_to_relative_ns_delay(wasi_clock: wasi::__wasi_subscription_clock_t) -> Result<u128> {
fn wasi_clock_to_relative_ns_delay(
wasi_clock: wasi::__wasi_subscription_clock_t,
) -> WasiResult<u128> {
use std::time::SystemTime;
if wasi_clock.flags != wasi::__WASI_SUBCLOCKFLAGS_SUBSCRIPTION_CLOCK_ABSTIME {
@@ -327,7 +332,7 @@ fn wasi_clock_to_relative_ns_delay(wasi_clock: wasi::__wasi_subscription_clock_t
}
let now: u128 = SystemTime::now()
.duration_since(SystemTime::UNIX_EPOCH)
.map_err(|_| Error::ENOTCAPABLE)?
.map_err(|_| WasiError::ENOTCAPABLE)?
.as_nanos();
let deadline = u128::from(wasi_clock.timeout);
Ok(deadline.saturating_sub(now))
@@ -357,6 +362,6 @@ pub(crate) fn proc_raise(
_wasi_ctx: &WasiCtx,
_memory: &mut [u8],
_sig: wasi::__wasi_signal_t,
) -> Result<()> {
) -> WasiResult<()> {
unimplemented!("proc_raise")
}