stty: support any baud on Linux, replace nix with rustix

[oech3]

• Closes stty: support arbitrary baudrate (at least on linux) as GNU coreutils 9.8 #8719 . rustix manages baud rate by u32 on all platforms. But OS itself should support any baud to actually use any baud. This PR adds support for any baud on Linux kernel (since bsd was already supported at nix crate).
• Closes stty: support B460800 and B921600 baud rates #14989 too since rustix has u32 -> enum decoder.

[codspeed]

Merging this PR will regress 1 benchmark

⚠️ 119 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• cksum_default
• du_wide_tree[(5000, 500)]
• cksum_multiple_files
• cksum_crc32b
• factor_multiple_u64s[2]
• cksum_sysv
• dd_copy_8k_blocks
• sort_long_line[10000]
• dd_copy_1m_blocks
• cp_preserve_metadata[(5, 4, 10)]
• …and 109 more

ℹ️ 1 benchmark has no flame graph

The flamegraph could not be generated because too much time was spent in runtime internals, making the visualization not useful for performance analysis.

• sort_dictionary_order[500000]

⚡ 2 improved benchmarks
❌ 1 regressed benchmark
✅ 398 untouched benchmarks
⏩ 70 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	factor_thirteen_39_bit_primes	8.7 s	9.5 s	-9.02%
⚡	Simulation	factor_three_39_bit_primes	800.7 ms	494.1 ms	+62.06%
⚡	Simulation	factor_five_38_bit_primes	1.8 s	1.6 s	+13.27%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing oech3:stty-unsafe (36d4d16) with main (2fb77e8)}

Footnotes

1. 70 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[github-actions]

GNU testsuite comparison:

Note: The gnu test tests/stty/bad-speed is now being skipped but was previously passing.

[xtqqczze]

Would it be possible to separate the refactor replacing nix with rustix from the fix for #8719 into separate PRs?

[oech3]

It is very difficult since rustix automatically supports any baud and nix and rustix cannot be mixed.

[xtqqczze]

if you add a workaround for a rustix issue, make sure to open an issue at https://github.com/bytecodealliance/rustix and link it in the comment.

[oech3]

updated

[xtqqczze]

Actually OLCUC doesn't exist on Apple targets, it was nix mistake...

$ rustc --print host-tuple
aarch64-apple-darwin
$ gstty olcuc  
gstty: invalid argument ‘olcuc’

[oech3]

But libc crate has. If it is functional, we could have an extension.

[xtqqczze]

bytecodealliance/rustix#1706

[xtqqczze]

$ uu-stty --version
stty (uutils coreutils) 0.12.0
$ uu-stty olcuc          
uu-stty: invalid argument 'olcuc'

[oech3]

So we don't lost anything if we removed apple (at here or different PR). OK?

[xtqqczze]

So we don't lost anything if we removed apple (at here or different PR). OK?

Apparently not:

$ git rev-parse HEAD                     
2fb77e8b927b5614438d288b0c72827a87106663
uutils-coreutils % cargo run -q --features unix stty olcuc
stty: invalid argument 'olcuc'

[xtqqczze]

Sorry for the confusion, but there is no issue with the PR, I also see the correct stty: invalid argument 'olcuc' error with oech3:stty-unsafe checked out. (when rebased onto #15360)

[oech3]

It is odd that stty is buildable in any cases.