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Use FILE_ATTRIBUTE_TAG_INFO to get reparse tag #101260

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merged 1 commit into from
Sep 2, 2022
Merged

Use FILE_ATTRIBUTE_TAG_INFO to get reparse tag #101260

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6 changes: 6 additions & 0 deletions library/std/src/sys/windows/c.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -454,6 +454,12 @@ pub enum FILE_INFO_BY_HANDLE_CLASS {
MaximumFileInfoByHandlesClass,
}

#[repr(C)]
pub struct FILE_ATTRIBUTE_TAG_INFO {
pub FileAttributes: DWORD,
pub ReparseTag: DWORD,
}

#[repr(C)]
pub struct FILE_DISPOSITION_INFO {
pub DeleteFile: BOOLEAN,
Expand Down
26 changes: 18 additions & 8 deletions library/std/src/sys/windows/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -326,10 +326,15 @@ impl File {
cvt(c::GetFileInformationByHandle(self.handle.as_raw_handle(), &mut info))?;
let mut reparse_tag = 0;
if info.dwFileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
let mut b =
Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
if let Ok((_, buf)) = self.reparse_point(&mut b) {
reparse_tag = (*buf).ReparseTag;
let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
cvt(c::GetFileInformationByHandleEx(
self.handle.as_raw_handle(),
c::FileAttributeTagInfo,
ptr::addr_of_mut!(attr_tag).cast(),
mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
))?;
if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
reparse_tag = attr_tag.ReparseTag;
}
}
Ok(FileAttr {
Expand Down Expand Up @@ -390,10 +395,15 @@ impl File {
attr.file_size = info.AllocationSize as u64;
attr.number_of_links = Some(info.NumberOfLinks);
if attr.file_type().is_reparse_point() {
let mut b =
Align8([MaybeUninit::<u8>::uninit(); c::MAXIMUM_REPARSE_DATA_BUFFER_SIZE]);
if let Ok((_, buf)) = self.reparse_point(&mut b) {
attr.reparse_tag = (*buf).ReparseTag;
let mut attr_tag: c::FILE_ATTRIBUTE_TAG_INFO = mem::zeroed();
cvt(c::GetFileInformationByHandleEx(
self.handle.as_raw_handle(),
c::FileAttributeTagInfo,
ptr::addr_of_mut!(attr_tag).cast(),
mem::size_of::<c::FILE_ATTRIBUTE_TAG_INFO>().try_into().unwrap(),
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Kind of goofy to do this here, but I guess I'm not opposed since the unwrap should vanish and I would generally like us to be more careful about a usize->dword.

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Yeah. I was thinking of our conversation here and noticed it codegened fine. But it is weird. I do think it'd ultimately be better to have a proper wrapper for these cases that can statically assert the size fits into a u32. And also something for the cases that could possibly fail.

))?;
if attr_tag.FileAttributes & c::FILE_ATTRIBUTE_REPARSE_POINT != 0 {
reparse_tag = attr_tag.ReparseTag;
}
}
Ok(attr)
Expand Down