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Move remove_dir_all impl into a module
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@ChrisDenton
ChrisDenton committed Aug 31, 2024
1 parent 0d63418 commit bb9d5c4
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Showing 5 changed files with 253 additions and 169 deletions.
5 changes: 4 additions & 1 deletion library/std/src/sys/pal/windows/api.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -254,7 +254,7 @@ pub struct WinError {
pub code: u32,
}
impl WinError {
const fn new(code: u32) -> Self {
pub const fn new(code: u32) -> Self {
Self { code }
}
}
Expand All @@ -272,8 +272,11 @@ impl WinError {
// tidy-alphabetical-start
pub const ACCESS_DENIED: Self = Self::new(c::ERROR_ACCESS_DENIED);
pub const ALREADY_EXISTS: Self = Self::new(c::ERROR_ALREADY_EXISTS);
pub const BAD_NET_NAME: Self = Self::new(c::ERROR_BAD_NET_NAME);
pub const BAD_NETPATH: Self = Self::new(c::ERROR_BAD_NETPATH);
pub const CANT_ACCESS_FILE: Self = Self::new(c::ERROR_CANT_ACCESS_FILE);
pub const DELETE_PENDING: Self = Self::new(c::ERROR_DELETE_PENDING);
pub const DIR_NOT_EMPTY: Self = Self::new(c::ERROR_DIR_NOT_EMPTY);
pub const DIRECTORY: Self = Self::new(c::ERROR_DIRECTORY);
pub const FILE_NOT_FOUND: Self = Self::new(c::ERROR_FILE_NOT_FOUND);
pub const INSUFFICIENT_BUFFER: Self = Self::new(c::ERROR_INSUFFICIENT_BUFFER);
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5 changes: 5 additions & 0 deletions library/std/src/sys/pal/windows/c/bindings.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@ Windows.Wdk.Storage.FileSystem.FILE_WRITE_THROUGH
Windows.Wdk.Storage.FileSystem.NtCreateFile
Windows.Wdk.Storage.FileSystem.NTCREATEFILE_CREATE_DISPOSITION
Windows.Wdk.Storage.FileSystem.NTCREATEFILE_CREATE_OPTIONS
Windows.Wdk.Storage.FileSystem.NtOpenFile
Windows.Wdk.Storage.FileSystem.NtReadFile
Windows.Wdk.Storage.FileSystem.NtWriteFile
Windows.Wdk.Storage.FileSystem.SYMLINK_FLAG_RELATIVE
Expand Down Expand Up @@ -1931,10 +1932,14 @@ Windows.Win32.Foundation.RtlNtStatusToDosError
Windows.Win32.Foundation.SetHandleInformation
Windows.Win32.Foundation.SetLastError
Windows.Win32.Foundation.STATUS_DELETE_PENDING
Windows.Win32.Foundation.STATUS_DIRECTORY_NOT_EMPTY
Windows.Win32.Foundation.STATUS_END_OF_FILE
Windows.Win32.Foundation.STATUS_FILE_DELETED
Windows.Win32.Foundation.STATUS_INVALID_HANDLE
Windows.Win32.Foundation.STATUS_INVALID_PARAMETER
Windows.Win32.Foundation.STATUS_NOT_IMPLEMENTED
Windows.Win32.Foundation.STATUS_PENDING
Windows.Win32.Foundation.STATUS_SHARING_VIOLATION
Windows.Win32.Foundation.STATUS_SUCCESS
Windows.Win32.Foundation.TRUE
Windows.Win32.Foundation.UNICODE_STRING
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5 changes: 5 additions & 0 deletions library/std/src/sys/pal/windows/c/windows_sys.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -105,6 +105,7 @@ windows_targets::link!("kernel32.dll" "system" fn WideCharToMultiByte(codepage :
windows_targets::link!("kernel32.dll" "system" fn WriteConsoleW(hconsoleoutput : HANDLE, lpbuffer : PCWSTR, nnumberofcharstowrite : u32, lpnumberofcharswritten : *mut u32, lpreserved : *const core::ffi::c_void) -> BOOL);
windows_targets::link!("kernel32.dll" "system" fn WriteFileEx(hfile : HANDLE, lpbuffer : *const u8, nnumberofbytestowrite : u32, lpoverlapped : *mut OVERLAPPED, lpcompletionroutine : LPOVERLAPPED_COMPLETION_ROUTINE) -> BOOL);
windows_targets::link!("ntdll.dll" "system" fn NtCreateFile(filehandle : *mut HANDLE, desiredaccess : FILE_ACCESS_RIGHTS, objectattributes : *const OBJECT_ATTRIBUTES, iostatusblock : *mut IO_STATUS_BLOCK, allocationsize : *const i64, fileattributes : FILE_FLAGS_AND_ATTRIBUTES, shareaccess : FILE_SHARE_MODE, createdisposition : NTCREATEFILE_CREATE_DISPOSITION, createoptions : NTCREATEFILE_CREATE_OPTIONS, eabuffer : *const core::ffi::c_void, ealength : u32) -> NTSTATUS);
windows_targets::link!("ntdll.dll" "system" fn NtOpenFile(filehandle : *mut HANDLE, desiredaccess : u32, objectattributes : *const OBJECT_ATTRIBUTES, iostatusblock : *mut IO_STATUS_BLOCK, shareaccess : u32, openoptions : u32) -> NTSTATUS);
windows_targets::link!("ntdll.dll" "system" fn NtReadFile(filehandle : HANDLE, event : HANDLE, apcroutine : PIO_APC_ROUTINE, apccontext : *const core::ffi::c_void, iostatusblock : *mut IO_STATUS_BLOCK, buffer : *mut core::ffi::c_void, length : u32, byteoffset : *const i64, key : *const u32) -> NTSTATUS);
windows_targets::link!("ntdll.dll" "system" fn NtWriteFile(filehandle : HANDLE, event : HANDLE, apcroutine : PIO_APC_ROUTINE, apccontext : *const core::ffi::c_void, iostatusblock : *mut IO_STATUS_BLOCK, buffer : *const core::ffi::c_void, length : u32, byteoffset : *const i64, key : *const u32) -> NTSTATUS);
windows_targets::link!("ntdll.dll" "system" fn RtlNtStatusToDosError(status : NTSTATUS) -> u32);
Expand Down Expand Up @@ -2982,10 +2983,14 @@ pub struct STARTUPINFOW {
}
pub type STARTUPINFOW_FLAGS = u32;
pub const STATUS_DELETE_PENDING: NTSTATUS = 0xC0000056_u32 as _;
pub const STATUS_DIRECTORY_NOT_EMPTY: NTSTATUS = 0xC0000101_u32 as _;
pub const STATUS_END_OF_FILE: NTSTATUS = 0xC0000011_u32 as _;
pub const STATUS_FILE_DELETED: NTSTATUS = 0xC0000123_u32 as _;
pub const STATUS_INVALID_HANDLE: NTSTATUS = 0xC0000008_u32 as _;
pub const STATUS_INVALID_PARAMETER: NTSTATUS = 0xC000000D_u32 as _;
pub const STATUS_NOT_IMPLEMENTED: NTSTATUS = 0xC0000002_u32 as _;
pub const STATUS_PENDING: NTSTATUS = 0x103_u32 as _;
pub const STATUS_SHARING_VIOLATION: NTSTATUS = 0xC0000043_u32 as _;
pub const STATUS_SUCCESS: NTSTATUS = 0x0_u32 as _;
pub const STD_ERROR_HANDLE: STD_HANDLE = 4294967284u32;
pub type STD_HANDLE = u32;
Expand Down
211 changes: 43 additions & 168 deletions library/std/src/sys/pal/windows/fs.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,11 @@ use crate::sys::handle::Handle;
use crate::sys::path::maybe_verbatim;
use crate::sys::time::SystemTime;
use crate::sys::{c, cvt, Align8};
use crate::sys_common::{ignore_notfound, AsInner, FromInner, IntoInner};
use crate::{fmt, ptr, slice, thread};
use crate::sys_common::{AsInner, FromInner, IntoInner};
use crate::{fmt, ptr, slice};

mod remove_dir_all;
use remove_dir_all::remove_dir_all_iterative;

pub struct File {
handle: Handle,
Expand Down Expand Up @@ -646,6 +649,22 @@ impl File {
Ok(info)
}
}

/// Deletes the file, consuming the file handle to ensure the delete occurs
/// as immediately as possible.
/// This attempts to use `posix_delete` but falls back to `win32_delete`
/// if that is not supported by the filesystem.
#[allow(unused)]
fn delete(self) -> Result<(), WinError> {
// If POSIX delete is not supported for this filesystem then fallback to win32 delete.
match self.posix_delete() {
Err(WinError::INVALID_PARAMETER)
| Err(WinError::NOT_SUPPORTED)
| Err(WinError::INVALID_FUNCTION) => self.win32_delete(),
result => result,
}
}

/// Delete using POSIX semantics.
///
/// Files will be deleted as soon as the handle is closed. This is supported
Expand All @@ -654,21 +673,23 @@ impl File {
///
/// If the operation is not supported for this filesystem or OS version
/// then errors will be `ERROR_NOT_SUPPORTED` or `ERROR_INVALID_PARAMETER`.
fn posix_delete(&self) -> io::Result<()> {
#[allow(unused)]
fn posix_delete(&self) -> Result<(), WinError> {
let info = c::FILE_DISPOSITION_INFO_EX {
Flags: c::FILE_DISPOSITION_FLAG_DELETE
| c::FILE_DISPOSITION_FLAG_POSIX_SEMANTICS
| c::FILE_DISPOSITION_FLAG_IGNORE_READONLY_ATTRIBUTE,
};
api::set_file_information_by_handle(self.handle.as_raw_handle(), &info).io_result()
api::set_file_information_by_handle(self.handle.as_raw_handle(), &info)
}

/// Delete a file using win32 semantics. The file won't actually be deleted
/// until all file handles are closed. However, marking a file for deletion
/// will prevent anyone from opening a new handle to the file.
fn win32_delete(&self) -> io::Result<()> {
#[allow(unused)]
fn win32_delete(&self) -> Result<(), WinError> {
let info = c::FILE_DISPOSITION_INFO { DeleteFile: c::TRUE as _ };
api::set_file_information_by_handle(self.handle.as_raw_handle(), &info).io_result()
api::set_file_information_by_handle(self.handle.as_raw_handle(), &info)
}

/// Fill the given buffer with as many directory entries as will fit.
Expand All @@ -684,21 +705,23 @@ impl File {
/// A symlink directory is simply an empty directory with some "reparse" metadata attached.
/// So if you open a link (not its target) and iterate the directory,
/// you will always iterate an empty directory regardless of the target.
fn fill_dir_buff(&self, buffer: &mut DirBuff, restart: bool) -> io::Result<bool> {
#[allow(unused)]
fn fill_dir_buff(&self, buffer: &mut DirBuff, restart: bool) -> Result<bool, WinError> {
let class =
if restart { c::FileIdBothDirectoryRestartInfo } else { c::FileIdBothDirectoryInfo };

unsafe {
let result = cvt(c::GetFileInformationByHandleEx(
self.handle.as_raw_handle(),
let result = c::GetFileInformationByHandleEx(
self.as_raw_handle(),
class,
buffer.as_mut_ptr().cast(),
buffer.capacity() as _,
));
match result {
Ok(_) => Ok(true),
Err(e) if e.raw_os_error() == Some(c::ERROR_NO_MORE_FILES as _) => Ok(false),
Err(e) => Err(e),
);
if result == 0 {
let err = api::get_last_error();
if err.code == c::ERROR_NO_MORE_FILES { Ok(false) } else { Err(err) }
} else {
Ok(true)
}
}
}
Expand Down Expand Up @@ -804,62 +827,6 @@ unsafe fn from_maybe_unaligned<'a>(p: *const u16, len: usize) -> Cow<'a, [u16]>
}
}

/// 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
// unfortunately opening a file relative to a parent is not supported by
// win32 functions. It is however a fundamental feature of the NT kernel.
//
// See https://docs.microsoft.com/en-us/windows/win32/api/winternl/nf-winternl-ntcreatefile
unsafe {
let mut handle = ptr::null_mut();
let mut io_status = c::IO_STATUS_BLOCK::PENDING;
let mut name_str = c::UNICODE_STRING::from_ref(name);
use crate::sync::atomic::{AtomicU32, Ordering};
// The `OBJ_DONT_REPARSE` attribute ensures that we haven't been
// tricked into following a symlink. However, it may not be available in
// earlier versions of Windows.
static ATTRIBUTES: AtomicU32 = AtomicU32::new(c::OBJ_DONT_REPARSE);
let object = c::OBJECT_ATTRIBUTES {
ObjectName: &mut name_str,
RootDirectory: parent.as_raw_handle(),
Attributes: ATTRIBUTES.load(Ordering::Relaxed),
..c::OBJECT_ATTRIBUTES::default()
};
let status = c::NtCreateFile(
&mut handle,
access,
&object,
&mut io_status,
crate::ptr::null_mut(),
0,
c::FILE_SHARE_DELETE | c::FILE_SHARE_READ | c::FILE_SHARE_WRITE,
c::FILE_OPEN,
// If `name` is a symlink then open the link rather than the target.
c::FILE_OPEN_REPARSE_POINT,
crate::ptr::null_mut(),
0,
);
// Convert an NTSTATUS to the more familiar Win32 error codes (aka "DosError")
if c::nt_success(status) {
Ok(File::from_raw_handle(handle))
} else if status == c::STATUS_DELETE_PENDING {
// We make a special exception for `STATUS_DELETE_PENDING` because
// otherwise this will be mapped to `ERROR_ACCESS_DENIED` which is
// very unhelpful.
Err(io::Error::from_raw_os_error(c::ERROR_DELETE_PENDING as i32))
} else if status == c::STATUS_INVALID_PARAMETER
&& ATTRIBUTES.load(Ordering::Relaxed) == c::OBJ_DONT_REPARSE
{
// Try without `OBJ_DONT_REPARSE`. See above.
ATTRIBUTES.store(0, Ordering::Relaxed);
open_link_no_reparse(parent, name, access)
} else {
Err(io::Error::from_raw_os_error(c::RtlNtStatusToDosError(status) as _))
}
}
}

impl AsInner<Handle> for File {
#[inline]
fn as_inner(&self) -> &Handle {
Expand Down Expand Up @@ -1142,114 +1109,22 @@ pub fn rmdir(p: &Path) -> io::Result<()> {
Ok(())
}

/// Open a file or directory without following symlinks.
fn open_link(path: &Path, access_mode: u32) -> io::Result<File> {
pub fn remove_dir_all(path: &Path) -> io::Result<()> {
// Open a file or directory without following symlinks.
let mut opts = OpenOptions::new();
opts.access_mode(access_mode);
opts.access_mode(c::FILE_LIST_DIRECTORY);
// `FILE_FLAG_BACKUP_SEMANTICS` allows opening directories.
// `FILE_FLAG_OPEN_REPARSE_POINT` opens a link instead of its target.
opts.custom_flags(c::FILE_FLAG_BACKUP_SEMANTICS | c::FILE_FLAG_OPEN_REPARSE_POINT);
File::open(path, &opts)
}

pub fn remove_dir_all(path: &Path) -> io::Result<()> {
let file = open_link(path, c::DELETE | c::FILE_LIST_DIRECTORY)?;
let file = File::open(path, &opts)?;

// Test if the file is not a directory or a symlink to a directory.
if (file.basic_info()?.FileAttributes & c::FILE_ATTRIBUTE_DIRECTORY) == 0 {
return Err(io::Error::from_raw_os_error(c::ERROR_DIRECTORY as _));
}

match ignore_notfound(remove_dir_all_iterative(&file, File::posix_delete)) {
Err(e) => {
if let Some(code) = e.raw_os_error() {
match code as u32 {
// If POSIX delete is not supported for this filesystem then fallback to win32 delete.
c::ERROR_NOT_SUPPORTED
| c::ERROR_INVALID_FUNCTION
| c::ERROR_INVALID_PARAMETER => {
remove_dir_all_iterative(&file, File::win32_delete)
}
_ => Err(e),
}
} else {
Err(e)
}
}
ok => ok,
}
}

fn remove_dir_all_iterative(f: &File, delete: fn(&File) -> io::Result<()>) -> io::Result<()> {
// When deleting files we may loop this many times when certain error conditions occur.
// This allows remove_dir_all to succeed when the error is temporary.
const MAX_RETRIES: u32 = 10;

let mut buffer = DirBuff::new();
let mut dirlist = vec![f.duplicate()?];

// FIXME: This is a hack so we can push to the dirlist vec after borrowing from it.
fn copy_handle(f: &File) -> mem::ManuallyDrop<File> {
unsafe { mem::ManuallyDrop::new(File::from_raw_handle(f.as_raw_handle())) }
}

let mut restart = true;
while let Some(dir) = dirlist.last() {
let dir = copy_handle(dir);

// Fill the buffer and iterate the entries.
let more_data = dir.fill_dir_buff(&mut buffer, restart)?;
restart = false;
for (name, is_directory) in buffer.iter() {
if is_directory {
let child_dir = open_link_no_reparse(
&dir,
&name,
c::SYNCHRONIZE | c::DELETE | c::FILE_LIST_DIRECTORY,
);
// On success, add the handle to the queue.
// If opening the directory fails we treat it the same as a file
if let Ok(child_dir) = child_dir {
dirlist.push(child_dir);
continue;
}
}
for i in 1..=MAX_RETRIES {
let result = open_link_no_reparse(&dir, &name, c::SYNCHRONIZE | c::DELETE);
match result {
Ok(f) => delete(&f)?,
// Already deleted, so skip.
Err(e) if e.kind() == io::ErrorKind::NotFound => break,
// Retry a few times if the file is locked or a delete is already in progress.
Err(e)
if i < MAX_RETRIES
&& (e.raw_os_error() == Some(c::ERROR_DELETE_PENDING as _)
|| e.raw_os_error() == Some(c::ERROR_SHARING_VIOLATION as _)) => {}
// Otherwise return the error.
Err(e) => return Err(e),
}
thread::yield_now();
}
}
// If there were no more files then delete the directory.
if !more_data {
if let Some(dir) = dirlist.pop() {
// Retry deleting a few times in case we need to wait for a file to be deleted.
for i in 1..=MAX_RETRIES {
let result = delete(&dir);
if let Err(e) = result {
if i == MAX_RETRIES || e.kind() != io::ErrorKind::DirectoryNotEmpty {
return Err(e);
}
thread::yield_now();
} else {
break;
}
}
}
}
}
Ok(())
// Remove the directory and all its contents.
remove_dir_all_iterative(file).io_result()
}

pub fn readlink(path: &Path) -> io::Result<PathBuf> {
Expand Down
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