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uucore: correctly truncate response if getgroups shrinks #6978

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Merged
merged 2 commits into from
Dec 19, 2024
Merged

uucore: correctly truncate response if getgroups shrinks #6978

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uucore: correctly truncate response if getgroups shrinks
santtu Dec 18, 2024
8c76d0a
Merge branch 'main' into patch-1
santtu Dec 19, 2024
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5 changes: 3 additions & 2 deletions src/uucore/src/lib/features/entries.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -83,13 +83,14 @@ pub fn get_groups() -> IOResult<Vec<gid_t>> {
if res == -1 {
let err = IOError::last_os_error();
if err.raw_os_error() == Some(libc::EINVAL) {
// Number of groups changed, retry
// Number of groups has increased, retry
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are you sure it is always increased ?

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POSIX.1-1988 on getgroups return value:

[EINVAL]
The gidsetsize argument is non-zero and less than the number of group IDs that would have been returned.

Since ngroups is based on earlier getgroups return value, the only case where EINVAL is returned when the indicated size (ngroups parameter for getgroups) is less than what the return list would be. If the reserved space is larger than the actual list, then res != -1.

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oh, cool, thanks :)

continue;
} else {
return Err(err);
}
} else {
groups.truncate(ngroups.try_into().unwrap());
// Number of groups may have decreased
groups.truncate(res.try_into().unwrap());
return Ok(groups);
}
}
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