'ls -l' reports spurious "No such file" under fs_mount (xattr syscalls not mediated)

[dmitrykruglov]

Under chroot="/" and fs_mount, the supervisor rewrites paths for openat/statx/newfstatat/faccessat/readlinkat/etc., but not the xattr family. So getxattr/lgetxattr/listxattr on a path under an fs_mount target resolve against the real (empty) mount point instead of the mounted source which leads to ENOENT.

Reproducible via ls -l, which probes xattrs for the ACL + / SELinux . indicator: the listing is correct (mediated statx), but ls also prints ls: <path>: No such file or directory and exits non-zero.

Repro (sandlock 0.8.1):

import os
from sandlock import Sandbox
src = "/tmp/xattr-demo"; os.makedirs(src, exist_ok=True)
open(src + "/f.txt", "w").write("hi")
sb = Sandbox(chroot="/", fs_mount={"/mnt": src},
             fs_readable=["/usr","/lib","/lib64","/bin","/sbin","/etc","/dev","/mnt"],
             fs_writable=["/mnt"], cwd="/mnt")
print(sb.run(["/bin/ls", "-l", "/mnt/f.txt"]))
# stdout: correct listing | stderr: "ls: /mnt/f.txt: No such file or directory" | exit 1

Inside the sandbox, os.stat("/mnt/f.txt") succeeds while lgetxattr("/mnt/f.txt", "system.posix_acl_access") returns errno 2 (ENOENT) — confirming it hit the real /mnt. statx/newfstatat/stat(1) are all fine; only *xattr is affected.

[congwang-mk]

Thanks for the report. xattr syscalls are indeed missing. I submitted PR #86 , please take a look.

[dmitrykruglov]

@congwang-mk, this looks right to me! Thanks so much for the incredibly quick PR, and for the library in general! :)