STD support for the Nintendo 3DS
Rustc already supports compiling for the Nintendo 3DS using the `armv6k-nintendo-3ds` target (Tier 3). Until now though, only `core` and `alloc` were supported. This PR adds standard library support for the Nintendo 3DS. A notable exclusion is `std::thread` support, which will come in a follow-up PR as it requires more complicated changes.
This has been a joint effort by `@Meziu,` `@ian-h-chamberlain,` myself, and prior work by `@rust3ds` members.
### Background
The Nintendo 3DS (Horizon OS) is a mostly-UNIX looking system, with the caveat that it does not come with a full libc implementation out of the box. On the homebrew side (I'm not under NDA), the libc interface is partially implemented by the [devkitPro](https://devkitpro.org/wiki/devkitPro_pacman) toolchain and a user library like [`libctru`](https://github.com/devkitPro/libctru). This is important because there are [some possible legal barriers](https://github.com/rust-lang/rust/pull/88529#issuecomment-919938396) to linking directly to a library that uses the underlying platform APIs, since they might be considered a trade secret or under NDA.
To get around this, the standard library impl for the 3DS does not directly depend on any platform-level APIs. Instead, it expects standard libc functions to be linked in. The implementation of these libc functions is left to the user. Some functions are provided by the devkitPro toolchain, but in our testing, we used the following to fill in the other functions:
- [`libctru`] - provides more basic APIs, such as `nanosleep`. Linked in by way of [`ctru-sys`](https://github.com/Meziu/ctru-rs/tree/master/ctru-sys).
- [`pthread-3ds`](https://github.com/Meziu/pthread-3ds) - provides pthread APIs for `std::thread`. Implemented using [`libctru`].
- [`linker-fix-3ds`](https://github.com/Meziu/rust-linker-fix-3ds) - fulfills some other missing libc APIs. Implemented using [`libctru`].
For more details, see the `src/doc/rustc/src/platform-support/armv6k-nintendo-3ds.md` file added in this PR.
### Notes
We've already upstreamed changes to the [`libc`] crate to support this PR, as well as the upcoming threading PR. These changes have all been released as of 0.2.121, so we bump the crate version in this PR.
Edit: After some rebases, the version bump has already been merged so it doesn't appear in this PR.
A lot of the changes in this PR are straightforward, and follow in the footsteps of the ESP-IDF target: https://github.com/rust-lang/rust/pull/87666.
The 3DS does not support user space process spawning, so these APIs are unimplemented (similar to ESP-IDF).
[`libctru`]: https://github.com/devkitPro/libctru
[`libc`]: https://github.com/rust-lang/libc
Fix use of SetHandleInformation on UWP
The use of `SetHandleInformation` (introduced in #96441 to make `HANDLE` inheritable) breaks UWP builds because it is not available for UWP targets.
Proposed workaround: duplicate the `HANDLE` with `inherit = true` and immediately close the old one. Traditional Windows Desktop programs are not affected.
cc `@ChrisDenton`
Add rustc_nonnull_optimization_guaranteed to Owned/Borrowed Fd/Socket
PR #94586 added support for using
`rustc_nonnull_optimization_guaranteed` on values where the "null" value
is the all-ones bitpattern.
Now that #94586 has made it to the stage0 compiler, add
`rustc_nonnull_optimization_guaranteed` to `OwnedFd`, `BorrowedFd`,
`OwnedSocket`, and `BorrowedSocket`, since these types all exclude
all-ones bitpatterns.
This allows `Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`,
and `Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
[I/O safety RFC]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md#ownedfd-and-borrowedfdfd-1
PR #94586 added support for using
`rustc_nonnull_optimization_guaranteed` on values where the "null" value
is the all-ones bitpattern.
Now that #94586 has made it to the stage0 compiler, add
`rustc_nonnull_optimization_guaranteed` to `OwnedFd`, `BorrowedFd`,
`OwnedSocket`, and `BorrowedSocket`, since these types all exclude
all-ones bitpatterns.
This allows `Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`,
and `Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
[I/O safety RFC]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md#ownedfd-and-borrowedfdfd-1
Clarify that when `BorrowedHandle`, `OwnedHandle`, or `HandleOrNull`
hold the value `-1`, it always means the current process handle, and not
`INVALID_HANDLE_VALUE`.
Make `BorrowedFd::borrow_raw` a const fn.
Making `BorrowedFd::borrow_raw` a const fn allows it to be used to
create a constant `BorrowedFd<'static>` holding constants such as
`AT_FDCWD`. This will allow [`rustix::fs::cwd`] to become a const fn.
For consistency, make similar changes to `BorrowedHandle::borrow_raw`
and `BorrowedSocket::borrow_raw`.
[`rustix::fs::cwd`]: https://docs.rs/rustix/latest/rustix/fs/fn.cwd.html
r? `@joshtriplett`
Remove `#[rustc_deprecated]`
This removes `#[rustc_deprecated]` and introduces diagnostics to help users to the right direction (that being `#[deprecated]`). All uses of `#[rustc_deprecated]` have been converted. CI is expected to fail initially; this requires #95958, which includes converting `stdarch`.
I plan on following up in a short while (maybe a bootstrap cycle?) removing the diagnostics, as they're only intended to be short-term.
Windows: Make stdin pipes synchronous
Stdin pipes do not need to be used asynchronously within the standard library. This is a first step in making pipes mostly synchronous.
r? `@m-ou-se`
Define a dedicated error type for `HandleOrNull` and `HandleOrInvalid`.
Define `NullHandleError` and `InvalidHandleError` types, that implement std::error::Error, and use them as the error types in `HandleOrNull` and `HandleOrInvalid`,
This addresses [this concern](https://github.com/rust-lang/rust/issues/87074#issuecomment-1080031167).
This is the same as #95387.
r? `@joshtriplett`
Making `BorrowedFd::borrow_raw` a const fn allows it to be used to
create a constant `BorrowedFd<'static>` holding constants such as
`AT_FDCWD`. This will allow [`rustix::fs::cwd`] to become a const fn.
For consistency, make similar changes to `BorrowedHandle::borrow_raw`
and `BorrowedSocket::borrow_raw`.
[`rustix::fs::cwd`]: https://docs.rs/rustix/latest/rustix/fs/fn.cwd.html
In the `TryFrom<HandleOrInvalid> for OwnedHandle` and
`TryFrom<HandleOrNull> for OwnedHandle` implemenations, `forget` the
owned handle on the error path, to avoid calling `CloseHandle` on an
invalid handle. It's harmless, except that it may overwrite the
thread's `GetLastError` error.
Add a `process_group` method to UNIX `CommandExt`
- Tracking issue: #93857
- RFC: https://github.com/rust-lang/rfcs/pull/3228
Add a `process_group` method to `std::os::unix::process::CommandExt` that
allows setting the process group id (i.e. calling `setpgid`) in the child, thus
enabling users to set process groups while leveraging the `posix_spawn` fast
path.
Consistently present absent stdio handles on Windows as NULL handles.
This addresses #90964 by making the std API consistent about presenting
absent stdio handles on Windows as NULL handles. Stdio handles may be
absent due to `#![windows_subsystem = "windows"]`, due to the console
being detached, or due to a child process having been launched from a
parent where stdio handles are absent.
Specifically, this fixes the case of child processes of parents with absent
stdio, which previously ended up with `stdin().as_raw_handle()` returning
`INVALID_HANDLE_VALUE`, which was surprising, and which overlapped with an
unrelated valid handle value. With this patch, `stdin().as_raw_handle()`
now returns null in these situation, which is consistent with what it
does in the parent process.
And, document this in the "Windows Portability Considerations" sections of
the relevant documentation.
