[ycbuzi]

What

libc.prx exports siginterrupt (TsrS8nGDQok, a libSceLibcInternal export in the public SDK's stub table) and runs FreeBSD 11.4's lib/libc/gen/siginterrupt.c sequence: read the signal's disposition with sigaction, set or clear the signal's bit in _sigintr and SA_RESTART in the flags, install the disposition again. EINVAL for a signal outside 1 to 128 comes from the first sigaction, as there.

libc cannot call libkernel (libkernel links libc), so this follows the pattern the pthread hooks already use: libc keeps a registered sigaction and the address of the _sigintr set (RegisterSigaction_nid_no_patch in General.hpp), and libkernel registers both from a static initializer in Signals.cpp when it loads, as RegisterPthreadOnLoad does in Thread.cpp. A call before that registration throws. The set is written outside libkernel's registration lock, as FreeBSD's libc writes it without one; the libc debt entry says so, and the libkernel signal entry from #8866 now points here.

Depends on #8866, which adds the _sigintr export and makes signal honour it; this branch is stacked on it and the diff shows both until it merges.

Tested

Windows 11, MinGW GCC 15.2.0, Release, BUILD_TESTING=ON, on main 05f9995 plus #8866:

• guest_signals, extended: siginterrupt(30, 1) sets bit 29 and clears SA_RESTART on the installed handler, a following signal(30) registers without SA_RESTART, siginterrupt(30, 0) clears the bit and restores SA_RESTART; the same on signal 128 (bit 127) with the default disposition; 0, -1 and 129 fail with EINVAL and leave the set alone. guest_signals passes (1 of 1).
• Revert check: with libkernel's registration commented out (everything else kept) the test fails, as siginterrupt throws; restored, it passes. It exits with 0xc0000409 and what(): siginterrupt: libkernel has not registered sigaction on the reverted build, and passes again on the restored one.
• tools/import_audit.py on a one-line registry importing TsrS8nGDQok from libSceLibcInternal.prx against the built libraries: implemented 1, absent 0; the tool exits 1 only to note that --libs has no file named libSceLibcInternal.prx, which libc.prx serves.
• python tools/check_conventions.py --base origin/main --head HEAD passes.
• Not run: Linux.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: feat(libkernel): export _sigintr and let signal honour it #8866
• Fixes: libkernel: public SDK _sigintr data object has no built provider #8846
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

🤖 Generated with Claude Code

[github-actions]

Progress report (65c393a → ec1be8a)

➖ System libraries: 53.23% (+0.0%, +1 implemented functions)

✅ 1 implemented

Library	Name
libc	siginterrupt_nid_postfix

[github-actions]

Other open pull requests touch the same code. Merging one will break the other, or both implement the same thing. If this one builds on them, list them in Depends on.

Pull request	Conflicting files (lines on main)	Same exports	Same new files
PR 6565	docs/dev/debt/libc.md L135
PR 7622	core/libs/prx/libc/src/Process.cpp L1

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 3965	docs/dev/debt/libc.md
PR 3986	core/libs/prx/libkernel/System/src/Signals.cpp core/libs/tests/GuestSignals.cpp
PR 4630	docs/dev/debt/libkernel.md
PR 5021	docs/dev/debt/libc.md docs/dev/debt/libkernel.md
PR 6044	core/libs/tests/GuestSignals.cpp
PR 6149	docs/dev/debt/libkernel.md
PR 6469	docs/dev/debt/libc.md docs/dev/debt/libkernel.md
PR 6740	docs/dev/debt/libkernel.md
PR 6819	docs/dev/debt/libc.md
PR 6879	docs/dev/debt/libc.md docs/dev/debt/libkernel.md
PR 6936	docs/dev/debt/libkernel.md
PR 6977	docs/dev/debt/libkernel.md
PR 7049	docs/dev/debt/libkernel.md
PR 7081	docs/dev/debt/libc.md
PR 7088	docs/dev/debt/libkernel.md
PR 7105	docs/dev/debt/libkernel.md
PR 7121	docs/dev/debt/libkernel.md
PR 7149	docs/dev/debt/libkernel.md
PR 7192	docs/dev/debt/libkernel.md
PR 7201	core/libs/prx/libkernel/System/src/Signals.cpp
PR 7447	docs/dev/debt/libc.md docs/dev/debt/libkernel.md
PR 7509	docs/dev/debt/libkernel.md
PR 7648	docs/dev/debt/libc.md
PR 7715	docs/dev/debt/libc.md
PR 8150	docs/dev/debt/libc.md
PR 8520	docs/dev/debt/libc.md docs/dev/debt/libkernel.md
PR 8523	docs/dev/debt/libkernel.md
PR 8546	docs/dev/debt/libc.md
PR 8550	docs/dev/debt/libc.md
PR 8553	docs/dev/debt/libkernel.md
PR 8658	core/libs/prx/libkernel/System/src/Signals.cpp docs/dev/debt/libkernel.md
PR 8726	docs/dev/debt/libkernel.md

[MarcZX10]

Manual review of the overlap warning: #6565 appends a libc debt entry at the end of debt/libc.md, where this PR also appends its siginterrupt entry; retain both entries when rebasing. The Signals.cpp overlap with #3986 is in blocked-signal/raise logic, while this PR adds the registration hook and updates signal for _sigintr; #7201/#7622 touch only alarm handling. Other debt-file overlaps are unrelated entries. The code overlap is line-disjoint; the only integration change I found is keeping both appended debt entries.

[ycbuzi]

Thanks for the overlap check. Noted for the rebase: both libc debt entries (#6565's and the siginterrupt one here) stay, and the Signals.cpp hunks (registration at the end of the file, the _sigintr line in signal) are apart from #3986's blocked-signal and raise changes.