[sguckiran]

What

Fixes boykopovar#5067. sceKernelConvertUtcToLocaltime and sceKernelConvertLocaltimeToUtc returned the time unchanged, while libc localtime follows the host zone. PPSA99203 (PS5SX2) draws its on-screen clock and its settings log times from sceKernelConvertUtcToLocaltime followed by gmtime_r (source). Because of that, it showed UTC as local time in boykopovar#5067.

• Both conversions now use the host zone's offset at the given instant: localtime_r/tm_gmtoff on POSIX and localtime_s with _get_timezone/_get_dstbias on Windows, the same sources libc localtime_s uses. Windows times outside the CRT range move by whole 400-year cycles, as libc does.
• KernelTimesec.west_sec holds the standard offset in seconds east of UTC, despite its name, and dst_sec holds the daylight saving seconds in effect. This follows PS5SX2's own notes from a console, where the call wrote 7200 and 3600, and shadPS4, which also stores seconds east. Whether west_sec includes daylight saving is not settled, and the open question is recorded in docs/dev/debt/libkernel.md.
• sceKernelConvertLocaltimeToUtc finds the offset in two passes. In a skipped or repeated local hour it takes the offset in effect one standard offset earlier (recorded as debt).
• sceKernelGettimezone and the gettimeofday time zone are unchanged (no offset, no daylight saving) and recorded as debt. fix(libSceSystemService): report the host time zone and summer time boykopovar/AnyPS5#5084 makes the matching change for sceSystemServiceParamGetInt.

Tested

Ubuntu 24.04, GCC 13.3, Release. guest_freebsd_clocks passes. It now pins TZ and checks both directions for UTC0, IST-5:30 (+5:30), BRT+3 (-3:00) and EST5EDT in January (-5:00) and July (-4:00 with 3600 s of daylight saving), including the KernelTimesec fields. It also passes with no zoneinfo files (TZDIR=/nonexistent) and with a host TZ=America/Toronto. The new checks abort on the previous Time.cpp. The existing identity and guard checks run under UTC0. Relinker-only build: all tests pass. Not tested on Windows or with a title.

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: none
• Unblocks: none
• AI-assisted: yes (Claude Code)

🤖 Generated with Claude Code

https://claude.ai/code/session_017iLxaSz4qjmirfqKZdhVQk