build: rename and gate systemd_logind configuration

[xtqqczze]

Rename the feat_systemd_logind feature to systemd_logind.

Prevent systemd_logind code from being enabled on unsupported platforms, improving cross-platform compilation and bringing the workspace closer to supporting:

cargo check -q --workspace --all-targets --all-features --target x86_64-pc-windows-gnu

[oech3]

We remove it at #11579 .

[github-actions]

Binary size comparison:

Individual binary size comparison VS main (threshold: >=5% AND >=4 KB).

Total size of compared binaries: 148.57 MB (+972 KB, +0.64%)

Significant per-binary changes:
  ls         2.11 MB ->    3.25 MB  (+1.14 MB, +54.36%)
  mkfifo     1.16 MB ->    1.08 MB  (-76 KB, -6.42%)
  mknod      1.16 MB ->    1.09 MB  (-76 KB, -6.38%)
  mkdir      1.16 MB ->    1.09 MB  (-72 KB, -6.04%)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/resolution (fails in this run but passes in the 'main' branch)

[codspeed]

Merging this PR will improve performance by 44.44%

⚠️ 120 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

• sort_mixed_utf8_locale
• du_wide_tree[(5000, 500)]
• cksum_raw_output
• dd_copy_partial
• cksum_sysv
• factor_multiple_u64s[2]
• cksum_default
• cksum_multiple_files
• du_all_wide_tree[(5000, 500)]
• cksum_crc
• …and 110 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]

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 2 improved benchmarks
✅ 399 untouched benchmarks
⏩ 70 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	factor_three_39_bit_primes	593.6 ms	348.4 ms	+70.41%
⚡	Simulation	factor_five_38_bit_primes	1.9 s	1.5 s	+22.44%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing xtqqczze:feat_systemd_logind (d86605d) with main (2e28cc3)}

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. ↩

[oech3]

I think systemd is better if it can be renamed. But I prefer #11579 .

[xtqqczze]

@sylvestre Regardless of whether #11579 is desirable (and I think it probably is), I still think we should merge this in the meantime. The merge conflicts should be straightforward to resolve.

[xtqqczze]

@sylvestre Could you merge this please; I have changes depending on this.

[xtqqczze]

@sylvestre ready

[oech3]

I like --features systemd for the case someone started using libsystemd.so much more (and shorter name).

[xtqqczze]

I like --features systemd for the case someone started using libsystemd.so much more (and shorter name).

Currently we are not using general libsystemd functionality; just the systemd-logind subsystem. So it is shorter, but potentially misleading because it suggests broader integration than actually exists.

[oech3]

It is not matter since we use openssl instead of openssl_api_name for cksum.

[xtqqczze]

It is not matter since we use openssl instead of openssl_api_name for cksum.

I think we have a feature named openssl to match the crate name, rather than anything particularly well considered.

[sylvestre]

Thanks for your PR

[oech3]

> cargo check --features systemd_logind
error: the package 'coreutils' does not contain this feature: systemd_logind
help: packages with the missing feature: uucore, uu_pinky, uu_uptime, uu_users, uu_who

[xtqqczze]

error: the package 'coreutils' does not contain this feature: systemd_logind

That's because it's still named feat_systemd_logind for coreutils, since we expect a feat_ prefix for the build script. feat_selinux is the same.

[oech3]

Different feature name breaks GNUmakefile when MULTICALL=* was changed.

[xtqqczze]

@oech3 Is there any breakage from this PR?

[oech3]

I opened #15454 .

make MULTICALL=y needs CARGOFLAGS=--features=feat_systemd_logind while make MULTICALL=n needs CARGOFLAGS=--features=systemd_logind.

[xtqqczze]

@oech3 Sorry, I don't understand the make workflow. Could you please share the command and error message for any breakage.

[oech3]

This is needed for consitency. If downstream wrote the buildscript using make, consumer needs to change feature name too just for changing multicall or individual.

[xtqqczze]

If there is no breakage from this PR then let’s discuss in #15454 instead.

[oech3]

Well... changing feature name is always breaking change for build script.

[xtqqczze]

I don’t see feat_systemd_logind referenced in any build scripts. Could you point to a specific build script or downstream use that breaks as a result of this change?

[oech3]

make MULTICALL=n UTILS=who CARGOFLAGS=--features=feat_systemd_logind is broken now.
UTILS=who is just an example.

[xtqqczze]

I’ll accept that renaming a feature can be a breaking change. However, without a compatibility requirement to preserve the old name, I don’t see why this is a problem. I won’t discuss this further in this thread.

[oech3]

I don't require compatibility for feature name i.e. I'm fine with make MULTICALL=n UTILS=who CARGOFLAGS=--features=systemd_logind. However ,if we use it, we should accept make MULTICALL=y UTILS=who CARGOFLAGS=--features=systemd_logind too.