Fix faccessat and add faccessat2#3578
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sporksmith merged 3 commits intoshadow:mainfrom May 3, 2025
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Doesn't pass yet under shadow
The implementation actually matches the faccessat2 syscall, which has a flags parameter. faccessat doesn't (though the libc wrapper does).
This is just like faccessat2, except doesn't take a flags parameter.
stevenengler
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Nice catch!
This looks similar to #3384. I wonder if we should audit all of these to make sure we don't have other instances of these 2/not-2 syscall handlers.
Maybe double check if you haven't that we don't need to make any changes to the libc wrappers in the shim? For example do we need to add faccessat2 somewhere in src/lib/preload-libc/gen_syscall_wrappers_c.py?
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Yup, those are already excluded. |
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Mostly to get the `faccessat` fix in <shadow/shadow#3578>. I don't *think* it's currently affecting these tests, but is a very confusing bug when it does bite.
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In particular, shadow/shadow#3578 fixes `faccessat` behavior that `test-network.sh` depends on (via shell tests like `-x`). get faccessat fix
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Our
faccessathandler incorrectly took an extra flags parameter, which was garbage data. This led to a heisenbug in chutney shell scripts, since sometimes the corresponding register would happen to have 0 and work, but sometimes it would have garbage data and cause the syscall to return an error.This renames the old handler to
faccessat2, which does take the flags parameter, and addsfaccessat, which doesn't.