Implement network primitives with ideal Rust layout, not C system layout
This PR is the result of this internals forum thread: https://internals.rust-lang.org/t/why-are-socketaddrv4-socketaddrv6-based-on-low-level-sockaddr-in-6/13321.
Instead of basing `std:::net::{Ipv4Addr, Ipv6Addr, SocketAddrV4, SocketAddrV6}` on system (C) structs, they are encoded in a more optimal and idiomatic Rust way.
This changes the public API of std by introducing structural equality impls for all four types here, which means that `match ipv4addr { SOME_CONSTANT => ... }` will now compile, whereas previously this was an error. No other intentional changes are introduced to public API.
It's possible to observe the current layout of these types (e.g., by pointer casting); most but not all libraries which were found by Crater to do this have had updates issued and affected versions yanked. See report below.
### Benefits of this change
- It will become possible to move these fundamental network types from `std` into `core` ([RFC](https://github.com/rust-lang/rfcs/pull/2832)).
- Some methods that can't be made `const fn`s today can be made `const fn`s with this change.
- `SocketAddrV4` only occupies 6 bytes instead of 16 bytes.
- These simple primitives become easier to read and uses less `unsafe`.
- Makes these types support structural equality, which means you can now (for instance) match an `Ipv4Addr` against a constant
### ~Remaining~ Previous problems
This change obviously changes the memory layout of the types. And it turns out some libraries invalidly assumes the memory layout and does very dangerous pointer casts to convert them. These libraries will have undefined behaviour and perform invalid memory access until patched.
- [x] - `mio` - Issue: https://github.com/tokio-rs/mio/issues/1386.
- [x] `0.7` branch https://github.com/tokio-rs/mio/pull/1388
- [x] `0.7.6` published https://github.com/tokio-rs/mio/pull/1398
- [x] Yank all `0.7` versions older than `0.7.6`
- [x] Report `<0.7.6` to RustSec Advisory Database https://rustsec.org/advisories/RUSTSEC-2020-0081.html
- [x] - `socket2` - Issue: https://github.com/rust-lang/socket2-rs/issues/119.
- [x] `0.3.x` branch https://github.com/rust-lang/socket2-rs/pull/120
- [x] `0.3.16` published
- [x] `master` branch https://github.com/rust-lang/socket2-rs/pull/122
- [x] Yank all `0.3` versions older than `0.3.16`
- [x] Report `<0.3.16` to RustSec Advisory Database https://rustsec.org/advisories/RUSTSEC-2020-0079.html
- [x] - `net2` - Issue: https://github.com/deprecrated/net2-rs/issues/105
- [x] https://github.com/deprecrated/net2-rs/pull/106
- [x] `0.2.36` published
- [x] Yank all `0.2` versions older than `0.2.36`
- [x] Report `<0.2.36` to RustSec Advisory Database https://rustsec.org/advisories/RUSTSEC-2020-0078.html
- [x] - `miow` - Issue: https://github.com/yoshuawuyts/miow/issues/38
- [x] `0.3.x` - https://github.com/yoshuawuyts/miow/pull/39
- [x] `0.3.6` published
- [x] `0.2.x` - https://github.com/yoshuawuyts/miow/pull/40
- [x] `0.2.2` published
- [x] Yanked all `0.2` versions older than `0.2.2`
- [x] Yanked all `0.3` versions older than `0.3.6`
- [x] Report `<0.2.2` and `<0.3.6` to RustSec Advisory Database https://rustsec.org/advisories/RUSTSEC-2020-0080.html
- [x] - `quinn master` (aka what became 0.7) - https://github.com/quinn-rs/quinn/issues/968https://github.com/quinn-rs/quinn/pull/987
- [x] - `quinn 0.6` - https://github.com/quinn-rs/quinn/pull/1045
- [x] - `quinn 0.5` - https://github.com/quinn-rs/quinn/pull/1046
- [x] - Release `0.7.0`, `0.6.2` and `0.5.4`
- [x] - `nb-connect` - https://github.com/smol-rs/nb-connect/issues/1
- [x] - Release `1.0.3`
- [x] - Yank all versions older than `1.0.3`
- [x] - `shadowsocks-rust` - https://github.com/shadowsocks/shadowsocks-rust/issues/462
- [ ] - `rio` - https://github.com/spacejam/rio/issues/44
- [ ] - `seaslug` - https://github.com/spacejam/seaslug/issues/1
#### Fixed crate versions
All crates I have found that assumed the memory layout have been fixed and published. The crates and versions that will continue working even as/if this PR is merged is (please upgrade these to help unblock this PR):
* `net2 0.2.36`
* `socket2 0.3.16`
* `miow 0.2.2`
* `miow 0.3.6`
* `mio 0.7.6`
* `mio 0.6.23` - Never had the invalid assumption itself, but has now been bumped to only allow fixed dependencies (`net2` + `miow`)
* `nb-connect 1.0.3`
* `quinn 0.5.4`
* `quinn 0.6.2`
### Release notes draft
This release changes the memory layout of `Ipv4Addr`, `Ipv6Addr`, `SocketAddrV4` and `SocketAddrV6`. The standard library no longer implements these as the corresponding `libc` structs (`sockaddr_in`, `sockaddr_in6` etc.). This internal representation was never exposed, but some crates relied on it anyway by unsafely transmuting. This change will cause those crates to make invalid memory accesses. Notably `net2 <0.2.36`, `socket2 <0.3.16`, `mio <0.7.6`, `miow <0.3.6` and a few other crates are affected. All known affected crates have been patched and have had fixed versions published over a year ago. If any affected crate is still in your dependency tree, you need to upgrade them before using this version of Rust.
This updates the standard library's documentation to use the new syntax. The
documentation is worthwhile to update as it should be more idiomatic
(particularly for features like this, which are nice for users to get acquainted
with). The general codebase is likely more hassle than benefit to update: it'll
hurt git blame, and generally updates can be done by folks updating the code if
(and when) that makes things more readable with the new format.
A few places in the compiler and library code are updated (mostly just due to
already having been done when this commit was first authored).
This removes all mutex/atomics based workarounds for non-monotonic clocks and makes the previously panicking methods saturating instead.
Effectively this moves the monotonization from `Instant` construction to the comparisons.
This has some observable effects, especially on platforms without monotonic clocks:
* Incorrectly ordered Instant comparisons no longer panic. This may hide some programming errors until someone actually looks at the resulting `Duration`
* `checked_duration_since` will now return `None` in more cases. Previously it only happened when one compared instants obtained in the wrong order or
manually created ones. Now it also does on backslides.
The upside is reduced complexity and lower overhead of `Instant::now`.
They are also removed from the prelude as per the decision in
https://github.com/rust-lang/rust/issues/87228.
stdarch and compiler-builtins are updated to work with the new, stable
asm! and global_asm! macros.
Move `os_str_bytes` to `sys::unix`
Followup to #84967, with `OsStrExt` and `OsStringExt` moved out of `sys_common`, there is no reason anymore for `os_str_bytes` to live in `sys_common` and not in sys. This pr moves it to the location `sys::unix::os_str` and reuses the code on other platforms via `#[path]` (as is common in `sys`) instead of importing.
Change environment variable getters to error recoverably
This PR changes the standard library environment variable getter functions to error recoverably (i.e. not panic) when given an invalid value.
On some platforms, it is invalid for environment variable names to contain `'\0'` or `'='`, or for their values to contain `'\0'`. Currently, the standard library panics when manipulating environment variables with names or values that violate these invariants. However, this behavior doesn't make a lot of sense, at least in the case of getters. If the environment variable is missing, the standard library just returns an error value, rather than panicking. It doesn't make sense to treat the case where the variable is invalid any differently from that. See the [internals thread](https://internals.rust-lang.org/t/why-should-std-var-panic/14847) for discussion. Thus, this PR changes the functions to error recoverably in this case as well.
If desired, I could change the functions that manipulate environment variables in other ways as well. I didn't do that here because it wasn't entirely clear what to change them to. Should they error silently or do something else? If someone tells me how to change them, I'm happy to implement the changes.
This fixes#86082, an ICE that arises from the current behavior. It also adds a regression test to make sure the ICE does not occur again in the future.
`@rustbot` label +T-libs
r? `@joshtriplett`
Redefine `ErrorKind::Other` and stop using it in std.
This implements the idea I shared yesterday in the libs meeting when we were discussing how to handle adding new `ErrorKind`s to the standard library: This redefines `Other` to be for *user defined errors only*, and changes all uses of `Other` in the standard library to a `#[doc(hidden)]` and permanently `#[unstable]` `ErrorKind` that users can not match on. This ensures that adding `ErrorKind`s at a later point in time is not a breaking change, since the user couldn't match on these errors anyway. This way, we use the `#[non_exhaustive]` property of the enum in a more effective way.
Open questions:
- How do we check this change doesn't cause too much breakage? Will a crate run help and be enough?
- How do we ensure we don't accidentally start using `Other` again in the standard library? We don't have a `pub(not crate)` or `#[deprecated(in this crate only)]`.
cc https://github.com/rust-lang/rust/pull/79965
cc `@rust-lang/libs` `@ijackson`
r? `@dtolnay`
Move `available_concurrency` implementation to `sys`
This splits out the platform-specific implementation of `available_concurrency` to the corresponding platforms under `sys`. No changes are made to the implementation.
Tidy didn't lint against this code being originally added outside of `sys` because of a bug (see #84677), this PR also reverts the exclusion that was introduced in that bugfix.
Tracking issue of `available_concurrency`: #74479
- Split `sys_common::RWLock` between `StaticRWLock` and `MovableRWLock`
- Unbox `RwLock` on some platforms (Windows, Wasm and unsupported)
- Simplify `RwLock::into_inner`
Rearrange SGX split module files
In #75979 several inlined modules were split out into multiple files.
This PR keeps the multiple files but moves a few things around to
organize things in a coherent way.
In #75979 several inlined modules were split out into multiple files.
This PR keeps the multiple files but moves a few things around to
organize things in a coherent way.
Be stricter about rejecting LLVM reserved registers in asm!
LLVM will silently produce incorrect code if these registers are used as operands.
cc `@rust-lang/wg-inline-asm`
