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Fix statx byte order on big-endian guests#1634
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Statx32/Statx64 (and their StatxTimestamp structs) were defined only as
little-endian ctypes.Structure, and ql_syscall_statx used them regardless
of guest endianness. Every other stat-family struct already has an explicit
big-endian variant selected by ql.arch.endian; statx was the lone gap.
On a big-endian guest (e.g. MIPS/MIPS64 EB) this byte-swaps every statx
field. In particular stx_mode loses its S_IFDIR bit, so a directory looks
like a plain file and `busybox ls /` just echoes the argument instead of
listing the directory.
Add Statx{32,64}EB / StatxTimestamp{32,64}EB (ctypes.BigEndianStructure,
reusing the little-endian field layouts) and pick them when the guest is
big-endian. The little-endian path is byte-for-byte unchanged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Drives ql_syscall_statx on a big-endian MIPS context and checks that stx_mode, read back in the guest's byte order, still reports a directory (S_IFDIR). Before the fix the statx struct was emitted little-endian regardless of guest endianness, so the type bits were byte-swapped and a directory looked like a regular file. Self-contained (no rootfs binary, runs on stock unicorn). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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What
Fixes
statxreturning a byte-swappedstruct statxon big-endian guests.ql_syscall_statxalways serialized the result with the little-endianStatx32/Statx64(ctypes.Structure), regardless of guest endianness. Every other stat-family struct instat.pyalready has a big-endian variant selected viaql.arch.endian;statxwas the only one missing it. On a big-endian guest this byte-swaps every field — most visiblystx_mode, which loses itsS_IFDIRbit, so a directory looks like a plain file (e.g.busybox ls /prints the path name instead of listing it). Modern glibc routesstat/fstatatthroughstatx, so this affects ordinary directory operations, not just directstatxcallers.Closes #1633.
How
Statx32EB/Statx64EB(andStatxTimestamp32EB/StatxTimestamp64EB) asctypes.BigEndianStructure, reusing the little-endian field layouts.ql_syscall_statxwhenql.arch.endian == QL_ENDIAN.EB.Test
test_elf.ELFTest.test_linux_statx_bigendiandrivesql_syscall_statxon a big-endian MIPS context and checks thatstx_mode, read back in the guest's byte order, still reports a directory. It is self-contained (no rootfs binary, runs on stock unicorn) and fails ondev(AssertionError), passes with this fix.Checklist