Skip to content

Commit

Permalink
std.windows: use atomic rename, if possible (#16717)
Browse files Browse the repository at this point in the history 
Mitigates #14978.

Uses the same strategy as in #16499 suggested by @squeek502
  • Loading branch information
matu3ba authored Aug 24, 2023
1 parent 6780a6b commit 7a834e2
Show file tree
Hide file tree
Showing 2 changed files with 87 additions and 24 deletions.
87 changes: 64 additions & 23 deletions lib/std/os.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2629,33 +2629,74 @@ pub fn renameatW(
};
defer windows.CloseHandle(src_fd);

const struct_buf_len = @sizeOf(windows.FILE_RENAME_INFORMATION) + (MAX_PATH_BYTES - 1);
var rename_info_buf: [struct_buf_len]u8 align(@alignOf(windows.FILE_RENAME_INFORMATION)) = undefined;
const struct_len = @sizeOf(windows.FILE_RENAME_INFORMATION) - 1 + new_path_w.len * 2;
if (struct_len > struct_buf_len) return error.NameTooLong;

const rename_info = @as(*windows.FILE_RENAME_INFORMATION, @ptrCast(&rename_info_buf));

rename_info.* = .{
.ReplaceIfExists = ReplaceIfExists,
.RootDirectory = if (std.fs.path.isAbsoluteWindowsWTF16(new_path_w)) null else new_dir_fd,
.FileNameLength = @as(u32, @intCast(new_path_w.len * 2)), // already checked error.NameTooLong
.FileName = undefined,
};
@memcpy(@as([*]u16, &rename_info.FileName)[0..new_path_w.len], new_path_w);
var need_fallback = true;
var rc: windows.NTSTATUS = undefined;
if (comptime builtin.target.os.version_range.windows.min.isAtLeast(.win10_rs1)) {
const struct_buf_len = @sizeOf(windows.FILE_RENAME_INFORMATION_EX) + (MAX_PATH_BYTES - 1);
var rename_info_buf: [struct_buf_len]u8 align(@alignOf(windows.FILE_RENAME_INFORMATION_EX)) = undefined;
const struct_len = @sizeOf(windows.FILE_RENAME_INFORMATION_EX) - 1 + new_path_w.len * 2;
if (struct_len > struct_buf_len) return error.NameTooLong;

const rename_info = @as(*windows.FILE_RENAME_INFORMATION_EX, @ptrCast(&rename_info_buf));
var io_status_block: windows.IO_STATUS_BLOCK = undefined;

var io_status_block: windows.IO_STATUS_BLOCK = undefined;
var flags: windows.ULONG = windows.FILE_RENAME_POSIX_SEMANTICS | windows.FILE_RENAME_IGNORE_READONLY_ATTRIBUTE;
if (ReplaceIfExists == windows.TRUE) flags |= windows.FILE_RENAME_REPLACE_IF_EXISTS;
rename_info.* = .{
.Flags = flags,
.RootDirectory = if (std.fs.path.isAbsoluteWindowsWTF16(new_path_w)) null else new_dir_fd,
.FileNameLength = @intCast(new_path_w.len * 2), // already checked error.NameTooLong
.FileName = undefined,
};
@memcpy(@as([*]u16, &rename_info.FileName)[0..new_path_w.len], new_path_w);
rc = windows.ntdll.NtSetInformationFile(
src_fd,
&io_status_block,
rename_info,
@intCast(struct_len), // already checked for error.NameTooLong
.FileRenameInformationEx,
);
switch (rc) {
.SUCCESS => return,
// INVALID_PARAMETER here means that the filesystem does not support FileRenameInformationEx
.INVALID_PARAMETER => {},
.DIRECTORY_NOT_EMPTY => return error.PathAlreadyExists,
.FILE_IS_A_DIRECTORY => return error.IsDir,
.NOT_A_DIRECTORY => return error.NotDir,
// For all other statuses, fall down to the switch below to handle them.
else => need_fallback = false,
}
}

const rc = windows.ntdll.NtSetInformationFile(
src_fd,
&io_status_block,
rename_info,
@as(u32, @intCast(struct_len)), // already checked for error.NameTooLong
.FileRenameInformation,
);
if (need_fallback) {
const struct_buf_len = @sizeOf(windows.FILE_RENAME_INFORMATION) + (MAX_PATH_BYTES - 1);
var rename_info_buf: [struct_buf_len]u8 align(@alignOf(windows.FILE_RENAME_INFORMATION)) = undefined;
const struct_len = @sizeOf(windows.FILE_RENAME_INFORMATION) - 1 + new_path_w.len * 2;
if (struct_len > struct_buf_len) return error.NameTooLong;

const rename_info = @as(*windows.FILE_RENAME_INFORMATION, @ptrCast(&rename_info_buf));
var io_status_block: windows.IO_STATUS_BLOCK = undefined;

rename_info.* = .{
.Flags = ReplaceIfExists,
.RootDirectory = if (std.fs.path.isAbsoluteWindowsWTF16(new_path_w)) null else new_dir_fd,
.FileNameLength = @intCast(new_path_w.len * 2), // already checked error.NameTooLong
.FileName = undefined,
};
@memcpy(@as([*]u16, &rename_info.FileName)[0..new_path_w.len], new_path_w);

rc =
windows.ntdll.NtSetInformationFile(
src_fd,
&io_status_block,
rename_info,
@intCast(struct_len), // already checked for error.NameTooLong
.FileRenameInformation,
);
}

switch (rc) {
.SUCCESS => return,
.SUCCESS => {},
.INVALID_HANDLE => unreachable,
.INVALID_PARAMETER => unreachable,
.OBJECT_PATH_SYNTAX_BAD => unreachable,
Expand Down
24 changes: 23 additions & 1 deletion lib/std/os/windows.zig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1009,6 +1009,7 @@ pub fn DeleteFile(sub_path_w: []const u16, options: DeleteFileOptions) DeleteFil
.FileDispositionInformationEx,
);
switch (rc) {
.SUCCESS => return,
// INVALID_PARAMETER here means that the filesystem does not support FileDispositionInformationEx
.INVALID_PARAMETER => {},
// For all other statuses, fall down to the switch below to handle them.
Expand Down Expand Up @@ -2856,8 +2857,29 @@ const FILE_DISPOSITION_FORCE_IMAGE_SECTION_CHECK: ULONG = 0x00000004;
const FILE_DISPOSITION_ON_CLOSE: ULONG = 0x00000008;
const FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE: ULONG = 0x00000010;

// FILE_RENAME_INFORMATION.Flags
pub const FILE_RENAME_REPLACE_IF_EXISTS = 0x00000001;
pub const FILE_RENAME_POSIX_SEMANTICS = 0x00000002;
pub const FILE_RENAME_SUPPRESS_PIN_STATE_INHERITANCE = 0x00000004;
pub const FILE_RENAME_SUPPRESS_STORAGE_RESERVE_INHERITANCE = 0x00000008;
pub const FILE_RENAME_NO_INCREASE_AVAILABLE_SPACE = 0x00000010;
pub const FILE_RENAME_NO_DECREASE_AVAILABLE_SPACE = 0x00000020;
pub const FILE_RENAME_PRESERVE_AVAILABLE_SPACE = 0x00000030;
pub const FILE_RENAME_IGNORE_READONLY_ATTRIBUTE = 0x00000040;
pub const FILE_RENAME_FORCE_RESIZE_TARGET_SR = 0x00000080;
pub const FILE_RENAME_FORCE_RESIZE_SOURCE_SR = 0x00000100;
pub const FILE_RENAME_FORCE_RESIZE_SR = 0x00000180;

pub const FILE_RENAME_INFORMATION = extern struct {
ReplaceIfExists: BOOLEAN,
Flags: BOOLEAN,
RootDirectory: ?HANDLE,
FileNameLength: ULONG,
FileName: [1]WCHAR,
};

// FileRenameInformationEx (since .win10_rs1)
pub const FILE_RENAME_INFORMATION_EX = extern struct {
Flags: ULONG,
RootDirectory: ?HANDLE,
FileNameLength: ULONG,
FileName: [1]WCHAR,
Expand Down

0 comments on commit 7a834e2

Please sign in to comment.