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Rollup merge of #104558 - thomcc:unalign-diriter, r=ChrisDenton

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Don't assume `FILE_ID_BOTH_DIR_INFO` will be aligned

Fixes #104530. See that issue for info.

r? `@ChrisDenton`
This commit is contained in:
Matthias Krüger 2022-11-20 18:21:47 +01:00 committed by GitHub
commit 379d3365fd
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 23 additions and 10 deletions
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33
library/std/src/sys/windows/fs.rs
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@ -1,5 +1,6 @@
use crate::os::windows::prelude::*;
use crate::borrow::Cow;
use crate::ffi::OsString;
use crate::fmt;
use crate::io::{self, BorrowedCursor, Error, IoSlice, IoSliceMut, SeekFrom};
@ -719,7 +720,7 @@ impl<'a> DirBuffIter<'a> {
}
}
impl<'a> Iterator for DirBuffIter<'a> {
type Item = (&'a [u16], bool);
type Item = (Cow<'a, [u16]>, bool);
fn next(&mut self) -> Option<Self::Item> {
use crate::mem::size_of;
let buffer = &self.buffer?[self.cursor..];
@ -734,15 +735,19 @@ impl<'a> Iterator for DirBuffIter<'a> {
// `FileNameLength` bytes)
let (name, is_directory, next_entry) = unsafe {
let info = buffer.as_ptr().cast::<c::FILE_ID_BOTH_DIR_INFO>();
// Guaranteed to be aligned in documentation for
// While this is guaranteed to be aligned in documentation for
// https://docs.microsoft.com/en-us/windows/win32/api/winbase/ns-winbase-file_id_both_dir_info
assert!(info.is_aligned());
let next_entry = (*info).NextEntryOffset as usize;
let name = crate::slice::from_raw_parts(
// it does not seem that reality is so kind, and assuming this
// caused crashes in some cases (https://github.com/rust-lang/rust/issues/104530)
// presumably, this can be blamed on buggy filesystem drivers, but who knows.
let next_entry = ptr::addr_of!((*info).NextEntryOffset).read_unaligned() as usize;
let length = ptr::addr_of!((*info).FileNameLength).read_unaligned() as usize;
let attrs = ptr::addr_of!((*info).FileAttributes).read_unaligned();
let name = from_maybe_unaligned(
ptr::addr_of!((*info).FileName).cast::<u16>(),
(*info).FileNameLength as usize / size_of::<u16>(),
length / size_of::<u16>(),
);
let is_directory = ((*info).FileAttributes & c::FILE_ATTRIBUTE_DIRECTORY) != 0;
let is_directory = (attrs & c::FILE_ATTRIBUTE_DIRECTORY) != 0;
(name, is_directory, next_entry)
};
@ -755,13 +760,21 @@ impl<'a> Iterator for DirBuffIter<'a> {
// Skip `.` and `..` pseudo entries.
const DOT: u16 = b'.' as u16;
match name {
match &name[..] {
[DOT] | [DOT, DOT] => self.next(),
_ => Some((name, is_directory)),
}
}
}
unsafe fn from_maybe_unaligned<'a>(p: *const u16, len: usize) -> Cow<'a, [u16]> {
if p.is_aligned() {
Cow::Borrowed(crate::slice::from_raw_parts(p, len))
} else {
Cow::Owned((0..len).map(|i| p.add(i).read_unaligned()).collect())
}
}
/// Open a link relative to the parent directory, ensure no symlinks are followed.
fn open_link_no_reparse(parent: &File, name: &[u16], access: u32) -> io::Result<File> {
// This is implemented using the lower level `NtCreateFile` function as
@ -1117,13 +1130,13 @@ fn remove_dir_all_iterative(f: &File, delete: fn(&File) -> io::Result<()>) -> io
if is_directory {
let child_dir = open_link_no_reparse(
&dir,
name,
&name,
c::SYNCHRONIZE | c::DELETE | c::FILE_LIST_DIRECTORY,
)?;
dirlist.push(child_dir);
} else {
for i in 1..=MAX_RETRIES {
let result = open_link_no_reparse(&dir, name, c::SYNCHRONIZE | c::DELETE);
let result = open_link_no_reparse(&dir, &name, c::SYNCHRONIZE | c::DELETE);
match result {
Ok(f) => delete(&f)?,
// Already deleted, so skip.