This is technically "not necessary", as we will "just" segfault instead
if we e.g. arrive inside the handler fn with the null altstack. However,
it seems incorrect to go about this hoping that segfaulting is okay,
seeing as how our purpose here is to mitigate stack overflow problems.
Make sure NEED_ALTSTACK syncs with PAGE_SIZE when we do.
Co-authored-by: Jonas Böttiger <jonasboettiger@icloud.com>
Make os/windows and pal/windows default to `#![deny(unsafe_op_in_unsafe_fn)]`
This is to prevent regressions in modules that currently pass. I did also fix up a few trivial places where the module contained only one or two simple wrappers. In more complex cases we should try to ensure the `unsafe` blocks are appropriately scoped and have any appropriate safety comments.
This does not fix the windows bits of #127747 but it should help prevent regressions until that is done and also make it more obvious specifically which modules need attention.
std: `#![deny(unsafe_op_in_unsafe_fn)]` in platform-independent code
This applies the `unsafe_op_in_unsafe_fn` lint in all places in std that _do not have platform-specific cfg in their code_. For all such places, the lint remains allowed, because they need further work to address the relevant concerns. This list includes:
- `std::backtrace_rs` (internal-only)
- `std::sys` (internal-only)
- `std::os`
Notably this eliminates all "unwrapped" unsafe operations in `std::io` and `std::sync`, which will make them much more auditable in the future. Such has *also* been left for future work. While I made a few safety comments along the way on interfaces I have grown sufficiently familiar with, in most cases I had no context, nor particular confidence the unsafety was correct.
In the cases where I was able to determine the unsafety was correct without having prior context, it was obviously redundant. For example, an unsafe function calling another unsafe function that has the exact same contract, forwarding its caller's requirements just as it forwards its actual call.
Windows: Remove some unnecessary type aliases
Back in the olden days, C did not have fixed-width types so these type aliases were at least potentially useful. Nowadays, and especially in Rust, we don't need the aliases and they don't help with anything. Notably the windows bindings we use also don't bother with the aliases. And even when we have used aliases they're often only used once then forgotten about.
The only one that gives me pause is `DWORD` because it's used a fair bit. But it's still used inconsistently and we implicitly assume it's a `u32` anyway (e.g. `as` casting from an `i32`).
std: removes logarithms family function edge cases handling for solaris.
Issue had been fixed over time with solaris, 11.x behaves correctly
(and we support it as minimum), illumos works correctly too.
Merge Apple `std::os` extensions modules into `std::os::darwin`
The functionality available on Apple platforms are very similar, and were (basically) duplicated for each platform.
This PR rectifies that by merging the code into one module.
Ultimately, I've done this to fix `./x build library --target=aarch64-apple-tvos,aarch64-apple-watchos,aarch64-apple-visionos`, as that currently fails because of dead code warnings.
Publically exposing these to tvOS/watchOS/visionOS targets is considered in https://github.com/rust-lang/rust/pull/123723, but that seems to be dragging out, and in any case I think it makes sense to do the refactor separately from stabilization.
r? libs
Fixes https://github.com/rust-lang/rust/issues/121640 and https://github.com/rust-lang/rust/issues/124825.
The functionality available on Apple platforms are very similar, and
were duplicated for each platform.
Additionally, this fixes a warning when compiling the standard library
for tvOS, watchOS and visionOS by marking the corresponding code as
dead code.
Use ManuallyDrop in BufWriter::into_parts
The fact that `mem::forget` takes by value means that it interacts very poorly with Stacked Borrows; generally users think of calling it as a no-op, but in Stacked Borrows, the field retagging tends to cause surprise tag invalidation.
