Manual Debug for Unix ExitCode ExitStatus ExitStatusError
These structs have misleading names. An ExitStatus[Error] is actually a Unix wait status; an ExitCode is actually an exit status. These misleading names appear in the `Debug` output.
The `Display` impls on Unix have been improved, but the `Debug` impls are still misleading, as reported in #74832.
Fix this by pretending that these internal structs are called `unix_exit_status` and `unix_wait_status` as applicable. (We can't actually rename the structs because of the way that the cross-platform machinery works: the names are cross-platform.)
After this change, this program
```
#![feature(exit_status_error)]
fn main(){
let x = std::process::Command::new("false").status().unwrap();
dbg!(x.exit_ok());
eprintln!("x={:?}",x);
}
```
produces this output
```
[src/main.rs:4] x.exit_ok() = Err(
ExitStatusError(
unix_wait_status(
256,
),
),
)
x=ExitStatus(unix_wait_status(256))
```
Closes#74832
Remove unnecessary unsafe block in `process_unix`
Because it's nested under this unsafe fn!
This block isn't detected as unnecessary because of a bug in the compiler: #88260.
This allows using longer paths for filesystem operations without the user needing to `canonicalize` or manually prefix paths.
If the path is already verbatim than this has no effect.
On MinGW toolchains the various features (such as function sections)
necessary to eliminate dead function references are disabled due to
various bugs. This means that the windows sockets library will most
likely remain linked to any mingw toolchain built program that also
utilizes libstd.
That said, I made an attempt to also enable `function-sections` and
`--gc-sections` during my experiments, but the symbol references
remained, sadly.
Restructure std::rt
These changes should reduce binary size slightly while at the same slightly improving performance of startup, thread spawning and `std:🧵:current()`. I haven't verified if the compiler is able to optimize some of these cases already, but at least for some others the compiler is unable to do these optimizations as they slightly change behavior in cases where program startup would crash anyway by omitting a backtrace and panic location.
I can remove 6f6bb16 if preferred.
The reference automatically coerces to a pointer. Writing an explicit
cast here is slightly misleading because that's most commonly used when
a pointer needs to be converted from one pointer type to another, e.g.
`*const c_void` to `*const sigaction` or vice versa.
SOLID[1] is an embedded development platform provided by Kyoto
Microcomputer Co., Ltd. This commit introduces a basic Tier 3 support
for SOLID.
# New Targets
The following targets are added:
- `aarch64-kmc-solid_asp3`
- `armv7a-kmc-solid_asp3-eabi`
- `armv7a-kmc-solid_asp3-eabihf`
SOLID's target software system can be divided into two parts: an
RTOS kernel, which is responsible for threading and synchronization,
and Core Services, which provides filesystems, networking, and other
things. The RTOS kernel is a μITRON4.0[2][3]-derived kernel based on
the open-source TOPPERS RTOS kernels[4]. For uniprocessor systems
(more precisely, systems where only one processor core is allocated for
SOLID), this will be the TOPPERS/ASP3 kernel. As μITRON is
traditionally only specified at the source-code level, the ABI is
unique to each implementation, which is why `asp3` is included in the
target names.
More targets could be added later, as we support other base kernels
(there are at least three at the point of writing) and are interested
in supporting other processor architectures in the future.
# C Compiler
Although SOLID provides its own supported C/C++ build toolchain, GNU Arm
Embedded Toolchain seems to work for the purpose of building Rust.
# Unresolved Questions
A μITRON4 kernel can support `Thread::unpark` natively, but it's not
used by this commit's implementation because the underlying kernel
feature is also used to implement `Condvar`, and it's unclear whether
`std` should guarantee that parking tokens are not clobbered by other
synchronization primitives.
# Unsupported or Unimplemented Features
Most features are implemented. The following features are not
implemented due to the lack of native support:
- `fs::File::{file_attr, truncate, duplicate, set_permissions}`
- `fs::{symlink, link, canonicalize}`
- Process creation
- Command-line arguments
Backtrace generation is not really a good fit for embedded targets, so
it's intentionally left unimplemented. Unwinding is functional, however.
## Dynamic Linking
Dynamic linking is not supported. The target platform supports dynamic
linking, but enabling this in Rust causes several problems.
- The linker invocation used to build the shared object of `std` is
too long for the platform-provided linker to handle.
- A linker script with specific requirements is required for the
compiled shared object to be actually loadable.
As such, we decided to disable dynamic linking for now. Regardless, the
users can try to create shared objects by manually invoking the linker.
## Executable
Building an executable is not supported as the notion of "executable
files" isn't well-defined for these targets.
[1] https://solid.kmckk.com/SOLID/
[2] http://ertl.jp/ITRON/SPEC/mitron4-e.html
[3] https://en.wikipedia.org/wiki/ITRON_project
[4] https://toppers.jp/
Fix WinUWP std compilation errors due to I/O safety
I/O safety for Windows has landed in #87329. However, it does not cover UWP specific parts and prevents all UWP targets from building. See https://github.com/YtFlow/Maple/issues/18. This PR fixes these compile errors when building std for UWP targets.
This is a straightforward wrapper that uses the existing helpers for C
string handling and errno handling.
Having this available is convenient for UNIX utility programs written in
Rust, and avoids having to call unsafe functions like `libc::chown`
directly and handle errors manually, in a program that may otherwise be
entirely safe code.
In addition, these functions provide a more Rustic interface by
accepting appropriate traits and using `None` rather than `-1`.
While issues have been seen on arm64 platforms the Arm architecture requires
that the counter monotonically increases and that it must provide a uniform
view of system time (e.g. it must not be possible for a core to receive a
message from another core with a time stamp and observe time going backwards
(ARM DDI 0487G.b D11.1.2). While there have been a few 64bit SoCs that have
bugs (#49281, #56940) which cause time to not monotonically increase, these have
been fixed in the Linux kernel and we shouldn't penalize all Arm SoCs for those
who refuse to update their kernels:
SUN50I_ERRATUM_UNKNOWN1 - Allwinner A64 / Pine A64 - fixed in 5.1
FSL_ERRATUM_A008585 - Freescale LS2080A/LS1043A - fixed in 4.10
HISILICON_ERRATUM_161010101 - Hisilicon 1610 - fixed in 4.11
ARM64_ERRATUM_858921 - Cortex A73 - fixed in 4.12
255a3f3e18 std: Force `Instant::now()` to be monotonic added a mutex to work around
this problem and a small test program using glommio shows the majority of time spent
acquiring and releasing this Mutex. 3914a7b0da tries to improve this, but actually
makes it worse on big systems as for 128b atomics a ldxp/stxp pair (and
successful loop) is required which is expensive as a lock and because of how
the load/store-exclusives scale on large Arm systems is both unfair to threads
and tends to go backwards in performance.
Allow writing of incomplete UTF-8 sequences to the Windows console via stdout/stderr
# Problem
Writes of just an incomplete UTF-8 byte sequence (e.g. `b"\xC3"` or `b"\xF0\x9F"`) to stdout/stderr with a Windows console attached error with `io::ErrorKind::InvalidData, "Windows stdio in console mode does not support writing non-UTF-8 byte sequences"` even though further writes could complete the codepoint. This is currently a rare occurence since the [linewritershim](2c56ea38b0/library/std/src/io/buffered/linewritershim.rs) implementation flushes complete lines immediately and buffers up to 1024 bytes for incomplete lines. It can still happen as described in #83258.
The problem will become more pronounced once the developer can switch stdout/stderr from line-buffered to block-buffered or immediate when the changes in the "Switchable buffering for Stdout" pull request (#78515) get merged.
# Patch description
If there is at least one valid UTF-8 codepoint all valid UTF-8 is passed through to the extracted `write_valid_utf8_to_console()` fn. The new code only comes into play if `write()` is being passed a short byte slice comprising an incomplete UTF-8 codepoint. In this case up to three bytes are buffered in the `IncompleteUtf8` struct associated with `Stdout` / `Stderr`. The bytes are accepted one at a time. As soon as an error can be detected `io::ErrorKind::InvalidData, "Windows stdio in console mode does not support writing non-UTF-8 byte sequences"` is returned. Once a complete UTF-8 codepoint is received it is passed to the `write_valid_utf8_to_console()` and the buffer length is set to zero.
Calling `flush()` will neither error nor write anything if an incomplete codepoint is present in the buffer.
# Tests
Currently there are no Windows-specific tests for console writing code at all. Writing (regression) tests for this problem is a bit challenging since unit tests and UI tests don't run in a console and suddenly popping up another console window might be surprising to developers running the testsuite and it might not work at all in CI builds. To just test the new functionality in unit tests the code would need to be refactored. Some guidance on how to proceed would be appreciated.
# Public API changes
* `std::str::verifications::utf8_char_width()` would be exposed as `std::str::utf8_char_width()` behind the "str_internals" feature gate.
# Related issues
* Fixes#83258.
* PR #78515 will exacerbate the problem.
# Open questions
* Add tests?
* Squash into one commit with better commit message?
Use the return value of readdir_r() instead of errno
POSIX says:
> If successful, the readdir_r() function shall return zero; otherwise,
> an error number shall be returned to indicate the error.
But we were previously using errno instead of the return value. This
led to issue #86649.
POSIX says:
> If successful, the readdir_r() function shall return zero; otherwise,
> an error number shall be returned to indicate the error.
But we were previously using errno instead of the return value. This
led to issue #86649.
These structs have misleading names. An ExitStatus[Error] is actually
a Unix wait status; an ExitCode is actually an exit status.
The Display impls are fixed, but the Debug impls are still misleading,
as reported in #74832.
Fix this by pretending that these internal structs are called
`unix_exit_status` and `unix_wait_status` as applicable. (We can't
actually rename the structs because of the way that the cross-platform
machinery works: the names are cross-platform.)
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Unbox mutexes, condvars and rwlocks on hermit
[RustyHermit](https://github.com/hermitcore/rusty-hermit) provides now movable synchronization primitives and we are able to unbox mutexes and condvars.
Change WASI's `RawFd` from `u32` to `c_int` (`i32`).
WASI previously used `u32` as its `RawFd` type, since its "file descriptors"
are unsigned table indices, and there's no fundamental reason why WASI can't
have more than 2^31 handles.
However, this creates myriad little incompability problems with code
that also supports Unix platforms, where `RawFd` is `c_int`. While WASI
isn't a Unix, it often shares code with Unix, and this difference made
such shared code inconvenient. #87329 is the most recent example of such
code.
So, switch WASI to use `c_int`, which is `i32`. This will mean that code
intending to support WASI should ideally avoid assuming that negative file
descriptors are invalid, even though POSIX itself says that file descriptors
are never negative.
This is a breaking change, but `RawFd` is considerd an experimental
feature in [the documentation].
[the documentation]: https://doc.rust-lang.org/stable/std/os/wasi/io/type.RawFd.html
r? `@alexcrichton`
WASI previously used `u32` as its `RawFd` type, since its "file descriptors"
are unsigned table indices, and there's no fundamental reason why WASI can't
have more than 2^31 handles.
However, this creates myriad little incompability problems with code
that also supports Unix platforms, where `RawFd` is `c_int`. While WASI
isn't a Unix, it often shares code with Unix, and this difference made
such shared code inconvenient. #87329 is the most recent example of such
code.
So, switch WASI to use `c_int`, which is `i32`. This will mean that code
intending to support WASI should ideally avoid assuming that negative file
descriptors are invalid, even though POSIX itself says that file descriptors
are never negative.
This is a breaking change, but `RawFd` is considerd an experimental
feature in [the documentation].
[the documentation]: https://doc.rust-lang.org/stable/std/os/wasi/io/type.RawFd.html
