Cesarus85--mjolnir-vr/docs/object_matching_logs/libcmt_file_obj.md

libs/libcmt/_file.obj exact-match ledger

This atomic lane began from campaign commit 037de80f and was rebased onto campaign commit b06c22ea before final validation. Before any production edit, _file.obj was confirmed MISSING at config index 741, absent from config/parked.json, absent from every local topic ref, object log, and worktree, and free of active peer ownership. The final commit is rebased and revalidated against the then-current campaign tip, recorded below.

Plain-English behavior

This object owns the C runtime's first twenty stream records. At startup it allocates the process-wide stream-pointer table, points its first twenty slots at those records, and marks the three standard streams invalid when the Xbox handle table says that no operating-system handle exists. At shutdown it flushes all streams and, during a normal exit, closes them. The remaining four functions lock and unlock either one of the twenty built-in stream slots or a dynamically allocated stream's embedded critical section.

Primary provenance and January inventory

The primary binary provenance is the authentic XDK 3911 libcmt.lib, whose SHA-256 is 60aa4c87c97eeb6662b31d9d37cf3caba1afabaec72c47b090e7a0ce8b632f55. Its extracted _file.obj member has SHA-256 0f659f05a07e38f9d222652d65108455f23af4da7f8694889b0bdd76e94c2517. CodeView identifies ordinary Microsoft C source d:\xbox-finalfre\private\sdktools\crt\crtw32\stdio\_file.c and compiler ID 0x001c2426. The matching public VC7 source topology is pinned at Git blob d813671b1f1a078968490fd12a0051aec1a86ea0 in QianNangong/VC6Ultimate, path VisualUltimate/WindowsSDKs/vc7/crt/src/_file.c.

The January target owns seven functions and four runtime data sections:

Symbol	Size	Relocations	Normalized SHA-256
___iob_func	6	1	fc9727eae305b45d1df8a58191610014e9104fa57b472dca0dbbded60cb84d82
___initstdio	169	13	27097e0d447d96c7a817fe6609aa0a27564c9bfe01707e1147034dd599401c75
___endstdio	20	3	a8f108bcdc223e3beba542f47f0be40deb27f8a46877d44962a94ac447eb2b2d
__lock_file	47	4	102647f55df903e0d2a761c3eefe014be43d72213218778e5322dc6fb77a7245
__lock_file2	35	2	4268b4ece7145487761b5501b52c2148a02f72c63250f02baec84d6644ab45f3
__unlock_file	47	4	102647f55df903e0d2a761c3eefe014be43d72213218778e5322dc6fb77a7245
__unlock_file2	35	2	4268b4ece7145487761b5501b52c2148a02f72c63250f02baec84d6644ab45f3

Owner	Section	Size	Relocations	Flags	Normalized SHA-256
__iob	.data	640	0	0xC0400040	0e4b0a8b9974a5f43361ef464f25e25ed9b87d058c70a5220f2083c523497724
__cflush	.bss	4	0	0xC0300080	df3f619804a92fdb4057192dc43dd748ea778adc52bc498ce80524c014b81119
_data_002b6aa4	.CRT$XIC	4	1	0xC0300040	df3f619804a92fdb4057192dc43dd748ea778adc52bc498ce80524c014b81119
_data_002b6ab4	.CRT$XPX	4	1	0xC0300040	df3f619804a92fdb4057192dc43dd748ea778adc52bc498ce80524c014b81119

Both initializer sections contain the correct pointer relocation, respectively to ___initstdio and ___endstdio. Every owner is external, has value zero, and has the same section name, contents, relocation identity and addend, and section characteristics as January.

The one csplit ownership distinction

The authentic archive member and January target are byte-identical in all runtime sections and code. Their sole symbolic distinction is relocation 10 inside ___initstdio: the archive spells the loop limit __iob + 640, while csplit gives that exact linked address the standalone external name _data_00319050. This is not an equivalence waiver. The reconstruction uses the source identifier data_00319050, whose normal C decoration produces the target's exact _data_00319050 relocation identity and zero addend.

Measured source-shape experiments

ID	One changed factor	Strict measurement	Result
E00	Compare the untouched archive member with January	All code bytes, code sizes, data bytes, section flags, and runtime relocations match; only the loop-bound relocation spelling is __iob+640 versus _data_00319050+0	Established authentic source and the csplit ownership split
E01	Faithful readable rewrite with a prechecked pointer loop ending at data_00319050	Six siblings exact; ___initstdio 176/169 bytes and 13/13 relocs, with an extra preheader and moved relocations	Rejected
E02	Use the same typed pointer traversal as a do/while	___initstdio restored to 169/169 and all 13 relocation addresses, types, identities, and addends matched; loop branch was unsigned jb instead of January's signed jl	Rejected
E03	Preserve the signed induction comparison used by the original integer-index loop	169/169 and 13/13 with one independent instruction pair reversed at loop entry: candidate loaded __iob before zeroing the index, January zeroed the index first	Rejected; declaration-order variants did not move it
E04	Express the authentic signed integer index explicitly, derive stream inside the loop, and compare the derived next-stream address with the csplit boundary	All seven functions strict-exact; all 359 meaningful code bytes, 29 relocation records, and four runtime owners exact	Accepted

E04 is not a speculative codegen trick. Microsoft's source iterates a signed integer across the twenty initial stream records; VC7 strength-reduces that index into a pointer. Retaining the signed induction is what explains January's jl. The explicitly named csplit boundary is required solely to preserve the target's independently proven relocation owner.

Strict validation

• XDK 3911 CL.Exe 13.00.9254.1 rebuilt the source with the generated, unchanged /O1 /Gy CRT flags.
• coff_compare reports all_equal: true for all seven functions, including exact relocation identities and addends.
• Hardened section comparison reports equality for __iob, __cflush, _data_002b6aa4, and _data_002b6ab4; section names, flags, owner storage, owner offsets, contents, and relocations also agree explicitly.
• Full halobetacache_build and libcmt_build succeeded after the final rebase. The generated build retained XDK 3911 CL.Exe 13.00.9254.1 and unchanged /O1 /Gy flags for this CRT translation unit.
• Regenerated progress credits _file.obj as complete. Campaign totals at this commit are 359/833 objects, 3,496/11,060 functions, and 415,875/2,198,102 code bytes overall. The libcmt slice is 92/212 objects, 148/476 functions, 9,869/55,015 code bytes, and 5,052/8,637 data bytes.
• Regenerated semantic evidence scanned 460 units and evaluated 3,585 functions, accepted 3,501 exact functions, and reported zero unit errors.
• The object-admission audit reports zero candidates and zero revocations. Its one contradicted source/shell/shell_xbox item is pre-existing and unrelated to this object.
• A clean unit regression snapshot followed by forced deletion and rebuilding of build/base/libs/libcmt/_file.obj reports all seven functions still_exact, with zero failures and zero warnings. The manifest also freezes and rechecks all non-code sections, symbol storage, aliases, and undefined imports.
• All 179 repository tooling tests pass. Configuration parsing, git diff --check, prohibited-source review, and final scope review are clean.

House, Berth, readability, and original-bug audit

The implementation uses named constants, named structures, size/offset assertions, vertically formatted prototypes, typed table access, and ordinary control flow. It preserves Microsoft's two-step allocation fallback and its standard-stream handle validation. Raw +0x20 and *0x28 accesses were not copied from disassembly: the critical-section and handle-table layouts are expressed as checked structures. The two data_seg pragmas are the authentic CRT mechanism that owns startup and shutdown callbacks; they are semantic section declarations, not compiler-tuning flags.

There is no assembly, volatile, forced inline/noinline annotation, undefined behavior, byte patch, alignment directive, compiler-flag change, comparator exception, or admission waiver. The 32-bit signed address comparison reflects the original signed integer induction on this fixed 32-bit Xbox target; it does not dereference the csplit boundary. No original behavioral bug was found, so no bug-preservation note is required.