xargs: Limit -n to {ARG_MAX}
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Authored by des on Jul 25 2025, 6:58 PM.

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Reviewers

jlduran
emaste
markj

Commits

rGb1e5e3b668e5: xargs: Limit -n to {ARG_MAX}
rG39bc7081b8a9: xargs: Limit -n to {ARG_MAX}
rGa7fa987abe1f: xargs: Limit -n to {ARG_MAX}

Summary

Since it's not possible to pass more than {ARG_MAX} bytes on the command
line, it's also not possible to pass more than {ARG_MAX} individual
arguments. Therefore, {ARG_MAX} is a reasonable upper bound for the -n
option. This resolves both the arithmetic overflow issue and the CI OOM
issue, so we can safely re-enable the test.

Fixes: eab91d008165
Fixes: 2682a1552724
MFC after: 1 week

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Skipped

Build Status

Buildable 65728
Build 62611: arc lint + arc unit

Event Timeline

des created this revision.Jul 25 2025, 6:58 PM

Herald added a subscriber: imp. · View Herald TranscriptJul 25 2025, 6:58 PM

des requested review of this revision.Jul 25 2025, 6:58 PM

Harbormaster completed remote builds in B65725: Diff 159126.Jul 25 2025, 6:58 PM

des added a child revision: D51537: xargs: Convert tests to ATF.Jul 25 2025, 6:58 PM

des mentioned this in D41040: xargs: Avoid a possible multiplication overflow.Jul 25 2025, 6:58 PM

des added reviewers: jlduran, emaste, markj.

seems reasonable

usr.bin/xargs/tests/regress.sh
15–16	since the filename is fixed as n524288.out anyway it seems using `$(())` is an unnecessary minor obfuscation

This revision is now accepted and ready to land.Jul 25 2025, 7:24 PM

des marked an inline comment as done.Jul 25 2025, 7:26 PM

des added inline comments.

usr.bin/xargs/tests/regress.sh
15–16	it gets dropped in D51537

des marked an inline comment as done.Jul 25 2025, 7:28 PM

des added inline comments.

usr.bin/xargs/tests/regress.sh
15–16	the reason for it btw is that's how `ARG_MAX` is defined in `sys/sys/syslimits.h`: #define ARG_MAX (2 * 256 * 1024) /* max bytes for an exec function */