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std.os.windows.GetFinalPathNameByHandle: address non-structural review comments

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Rohlem 2020-12-23 02:39:02 +01:00 committed by Andrew Kelley
parent 64c5f4979e
commit cb20503990
5 changed files with 80 additions and 87 deletions
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117
lib/std/os/windows.zig
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@ -29,7 +29,8 @@ pub const gdi32 = @import("windows/gdi32.zig");
pub usingnamespace @import("windows/bits.zig");
//version detection
usingnamespace std.zig.system.windows;
const version = std.zig.system.windows;
const WindowsVersion = version.WindowsVersion;
pub const self_process_handle = @intToPtr(HANDLE, maxInt(usize));
@ -963,42 +964,44 @@ pub fn QueryObjectName(
var full_buffer: [@sizeOf(OBJECT_NAME_INFORMATION) + PATH_MAX_WIDE * 2]u8 align(@alignOf(OBJECT_NAME_INFORMATION)) = undefined;
var info = @ptrCast(*OBJECT_NAME_INFORMATION, &full_buffer);
//buffer size is specified in bytes
const full_buffer_length = @intCast(ULONG, @sizeOf(OBJECT_NAME_INFORMATION) + std.math.min(PATH_MAX_WIDE, (out_buffer.len + 1) * 2));
//last argument would return the length required for full_buffer, not exposed here
const rc = ntdll.NtQueryObject(handle, .ObjectNameInformation, full_buffer[0..], full_buffer_length, null);
return switch (rc) {
.SUCCESS => if (@ptrCast(?[*]WCHAR, info.Name.Buffer)) |buffer| blk: {
const rc = ntdll.NtQueryObject(handle, .ObjectNameInformation, &full_buffer, full_buffer.len, null);
switch (rc) {
.SUCCESS => {
// info.Name.Buffer from ObQueryNameString is documented to be null (and MaximumLength == 0)
// if the object was "unnamed", not sure if this can happen for file handles
if (info.Name.MaximumLength == 0) return error.Unexpected;
//resulting string length is specified in bytes
const path_length_unterminated = @divExact(info.Name.Length, 2);
if (out_buffer.len < path_length_unterminated) {
return error.NameTooLong;
}
std.mem.copy(WCHAR, out_buffer[0..path_length_unterminated], buffer[0..path_length_unterminated :0]);
break :blk out_buffer[0..path_length_unterminated];
} else error.Unexpected,
.ACCESS_DENIED => error.AccessDenied,
.INVALID_HANDLE => error.InvalidHandle,
.BUFFER_OVERFLOW, .BUFFER_TOO_SMALL => error.NameTooLong,
mem.copy(WCHAR, out_buffer[0..path_length_unterminated], info.Name.Buffer[0..path_length_unterminated]);
return out_buffer[0..path_length_unterminated];
},
.ACCESS_DENIED => return error.AccessDenied,
.INVALID_HANDLE => return error.InvalidHandle,
.BUFFER_OVERFLOW, .BUFFER_TOO_SMALL => return error.NameTooLong,
//name_buffer.len >= @sizeOf(OBJECT_NAME_INFORMATION) holds statically
.INFO_LENGTH_MISMATCH => unreachable,
else => |e| unexpectedStatus(e),
};
else => |e| return unexpectedStatus(e),
}
}
test "QueryObjectName" {
if (comptime builtin.os.tag != .windows)
return;
//any file will do; canonicalization works on NTFS junctions and symlinks, hardlinks remain separate paths.
const file = try std.fs.openSelfExe(.{});
defer file.close();
//make this large enough for the test runner exe path
var out_buffer align(16) = std.mem.zeroes([1 << 10]u16);
var tmp = std.testing.tmpDir(.{});
defer tmp.cleanup();
const handle = tmp.dir.fd;
var out_buffer: [PATH_MAX_WIDE]u16 = undefined;
var result_path = try QueryObjectName(file.handle, out_buffer[0..]);
var result_path = try QueryObjectName(handle, &out_buffer);
//insufficient size
std.testing.expectError(error.NameTooLong, QueryObjectName(file.handle, out_buffer[0 .. result_path.len - 1]));
std.testing.expectError(error.NameTooLong, QueryObjectName(handle, out_buffer[0 .. result_path.len - 1]));
//exactly-sufficient size
_ = try QueryObjectName(file.handle, out_buffer[0..result_path.len]);
_ = try QueryObjectName(handle, out_buffer[0..result_path.len]);
}
pub const GetFinalPathNameByHandleError = error{
@ -1030,16 +1033,16 @@ pub fn GetFinalPathNameByHandle(
fmt: GetFinalPathNameByHandleFormat,
out_buffer: []u16,
) GetFinalPathNameByHandleError![]u16 {
var path_buffer: [std.math.max(@sizeOf(FILE_NAME_INFORMATION), @sizeOf(OBJECT_NAME_INFORMATION)) + PATH_MAX_WIDE * 2]u8 align(@alignOf(FILE_NAME_INFORMATION)) = undefined;
var path_buffer: [math.max(@sizeOf(FILE_NAME_INFORMATION), @sizeOf(OBJECT_NAME_INFORMATION)) + PATH_MAX_WIDE * 2]u8 align(@alignOf(FILE_NAME_INFORMATION)) = undefined;
var volume_buffer: [@sizeOf(FILE_NAME_INFORMATION) + MAX_PATH]u8 align(@alignOf(FILE_NAME_INFORMATION)) = undefined; // MAX_PATH bytes should be enough since it's Windows-defined name
var file_name_u16: []const u16 = undefined;
var volume_name_u16: []const u16 = undefined;
if ((comptime (targetVersionIsAtLeast(WindowsVersion.win10_rs4) != true)) //need explicit comptime, because error returns affect return type
and !runtimeVersionIsAtLeast(WindowsVersion.win10_rs4))
{
const final_path = QueryObjectName(hFile, std.mem.bytesAsSlice(u16, path_buffer[0..])) catch |err| return switch (err) {
error.InvalidHandle => error.FileNotFound, //close enough?
if ((comptime (std.builtin.os.version_range.windows.isAtLeast(WindowsVersion.win10_rs4) != true)) and !version.detectRuntimeVersion().isAtLeast(WindowsVersion.win10_rs4)) {
const final_path = QueryObjectName(hFile, mem.bytesAsSlice(u16, &path_buffer)) catch |err| return switch (err) {
// we assume InvalidHandle is close enough to FileNotFound in semantics
// to not further complicate the error set
error.InvalidHandle => error.FileNotFound,
else => |e| e,
};
@ -1047,39 +1050,40 @@ pub fn GetFinalPathNameByHandle(
if (out_buffer.len < final_path.len) {
return error.NameTooLong;
}
std.mem.copy(u16, out_buffer[0..], final_path[0..]);
return final_path; //we can directly return the slice we received
mem.copy(u16, out_buffer, final_path);
return out_buffer[0..final_path.len];
}
//otherwise we need to parse the string for volume path for the .Dos logic below to work
const expected_prefix = std.unicode.utf8ToUtf16LeStringLiteral("\\Device\\");
if (!std.mem.eql(u16, expected_prefix, final_path[0..expected_prefix.len])) {
//TODO find out if this can occur, and if we need to handle it differently
//(i.e. how to determine the end of a volume name)
return error.BadPathName;
}
const index = std.mem.indexOfPos(u16, final_path, expected_prefix.len, &[_]u16{'\\'}) orelse unreachable;
// TODO find out if a path can start with something besides `\Device\<volume name>`,
// and if we need to handle it differently
// (i.e. how to determine the start and end of the volume name in that case)
if (!mem.eql(u16, expected_prefix, final_path[0..expected_prefix.len])) return error.Unexpected;
const index = mem.indexOfPos(u16, final_path, expected_prefix.len, &[_]u16{'\\'}) orelse unreachable;
volume_name_u16 = final_path[0..index];
file_name_u16 = final_path[index..];
//fallthrough for fmt.volume_name != .Nt
} else {
// Get normalized path; doesn't include volume name though.
try QueryInformationFile(hFile, .FileNormalizedNameInformation, path_buffer[0..]);
const file_name = @ptrCast(*const FILE_NAME_INFORMATION, &path_buffer[0]);
file_name_u16 = @ptrCast([*]const u16, &file_name.FileName[0])[0..@divExact(file_name.FileNameLength, 2)];
try QueryInformationFile(hFile, .FileNormalizedNameInformation, &path_buffer);
const file_name = @ptrCast(*const FILE_NAME_INFORMATION, &path_buffer);
file_name_u16 = @ptrCast([*]const u16, &file_name.FileName)[0..@divExact(file_name.FileNameLength, 2)];
// Get NT volume name.
try QueryInformationFile(hFile, .FileVolumeNameInformation, volume_buffer[0..]);
const volume_name_info = @ptrCast(*const FILE_NAME_INFORMATION, &volume_buffer[0]);
volume_name_u16 = @ptrCast([*]const u16, &volume_name_info.FileName[0])[0..@divExact(volume_name_info.FileNameLength, 2)];
try QueryInformationFile(hFile, .FileVolumeNameInformation, &volume_buffer);
const volume_name_info = @ptrCast(*const FILE_NAME_INFORMATION, &volume_buffer);
volume_name_u16 = @ptrCast([*]const u16, &volume_name_info.FileName)[0..@divExact(volume_name_info.FileNameLength, 2)];
if (fmt.volume_name == .Nt) {
// Nothing to do, we simply copy the bytes to the user-provided buffer.
if (out_buffer.len < volume_name_u16.len + file_name_u16.len) return error.NameTooLong;
std.mem.copy(u16, out_buffer[0..], volume_name_u16);
std.mem.copy(u16, out_buffer[volume_name_u16.len..], file_name_u16);
mem.copy(u16, out_buffer, volume_name_u16);
mem.copy(u16, out_buffer[volume_name_u16.len..], file_name_u16);
return out_buffer[0 .. volume_name_u16.len + file_name_u16.len];
}
@ -1124,7 +1128,7 @@ pub fn GetFinalPathNameByHandle(
input_struct.DeviceNameLength = @intCast(USHORT, volume_name_u16.len * 2);
@memcpy(input_buf[@sizeOf(MOUNTMGR_MOUNT_POINT)..], @ptrCast([*]const u8, volume_name_u16.ptr), volume_name_u16.len * 2);
DeviceIoControl(mgmt_handle, IOCTL_MOUNTMGR_QUERY_POINTS, input_buf[0..], output_buf[0..]) catch |err| switch (err) {
DeviceIoControl(mgmt_handle, IOCTL_MOUNTMGR_QUERY_POINTS, &input_buf, &output_buf) catch |err| switch (err) {
error.AccessDenied => unreachable,
else => |e| return e,
};
@ -1144,22 +1148,20 @@ pub fn GetFinalPathNameByHandle(
// Look for `\DosDevices\` prefix. We don't really care if there are more than one symlinks
// with traditional DOS drive letters, so pick the first one available.
const prefix_u8 = "\\DosDevices\\";
var prefix_buf_u16: [prefix_u8.len]u16 = undefined;
const prefix_len_u16 = std.unicode.utf8ToUtf16Le(prefix_buf_u16[0..], prefix_u8[0..]) catch unreachable;
const prefix = prefix_buf_u16[0..prefix_len_u16];
var prefix_buf = std.unicode.utf8ToUtf16LeStringLiteral("\\DosDevices\\");
const prefix = prefix_buf[0..prefix_buf.len];
if (std.mem.startsWith(u16, symlink, prefix)) {
if (mem.startsWith(u16, symlink, prefix)) {
const drive_letter = symlink[prefix.len..];
if (out_buffer.len < drive_letter.len + file_name_u16.len) return error.NameTooLong;
std.mem.copy(u16, out_buffer[0..], drive_letter);
std.mem.copy(u16, out_buffer[drive_letter.len..], file_name_u16);
mem.copy(u16, out_buffer, drive_letter);
mem.copy(u16, out_buffer[drive_letter.len..], file_name_u16);
const total_len = drive_letter.len + file_name_u16.len;
// Validate that DOS does not contain any spurious nul bytes.
if (std.mem.indexOfScalar(u16, out_buffer[0..total_len], 0)) |_| {
if (mem.indexOfScalar(u16, out_buffer[0..total_len], 0)) |_| {
return error.BadPathName;
}
@ -1179,15 +1181,14 @@ test "GetFinalPathNameByHandle" {
return;
//any file will do
const file = try std.fs.openSelfExe(.{});
defer file.close();
const handle = file.handle;
//make this large enough for the test runner exe path
var buffer = std.mem.zeroes([1 << 10]u16);
var tmp = std.testing.tmpDir(.{});
defer tmp.cleanup();
const handle = tmp.dir.fd;
var buffer: [PATH_MAX_WIDE]u16 = undefined;
//check with sufficient size
const nt_length = (try GetFinalPathNameByHandle(handle, .{ .volume_name = .Nt }, buffer[0..])).len;
const dos_length = (try GetFinalPathNameByHandle(handle, .{ .volume_name = .Dos }, buffer[0..])).len;
const nt_length = (try GetFinalPathNameByHandle(handle, .{ .volume_name = .Nt }, &buffer)).len;
const dos_length = (try GetFinalPathNameByHandle(handle, .{ .volume_name = .Dos }, &buffer)).len;
//check with insufficient size
std.testing.expectError(error.NameTooLong, GetFinalPathNameByHandle(handle, .{ .volume_name = .Nt }, buffer[0 .. nt_length - 1]));

1
lib/std/os/windows/bits.zig
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@ -66,7 +66,6 @@ pub const SIZE_T = usize;
pub const TCHAR = if (UNICODE) WCHAR else u8;
pub const UINT = c_uint;
pub const ULONG_PTR = usize;
pub const PULONG = *ULONG;
pub const LONG_PTR = isize;
pub const DWORD_PTR = ULONG_PTR;
pub const UNICODE = false;

2
lib/std/os/windows/ntdll.zig
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@ -119,5 +119,5 @@ pub extern "NtDll" fn NtQueryObject(
ObjectInformationClass: OBJECT_INFORMATION_CLASS,
ObjectInformation: PVOID,
ObjectInformationLength: ULONG,
ReturnLength: ?PULONG,
ReturnLength: ?*ULONG,
) callconv(WINAPI) NTSTATUS;

31
lib/std/target.zig
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@ -95,7 +95,7 @@ pub const Target = struct {
win7 = 0x06010000,
win8 = 0x06020000,
win8_1 = 0x06030000,
win10 = 0x0A000000,
win10 = 0x0A000000, //aka win10_th1
win10_th2 = 0x0A000001,
win10_rs1 = 0x0A000002,
win10_rs2 = 0x0A000003,
@ -103,26 +103,35 @@ pub const Target = struct {
win10_rs4 = 0x0A000005,
win10_rs5 = 0x0A000006,
win10_19h1 = 0x0A000007,
win10_20h1 = 0x0A000008,
win10_vb = 0x0A000008, //aka win10_19h2
win10_mn = 0x0A000009, //aka win10_20h1
win10_fe = 0x0A00000A, //aka win10_20h2
_,
/// Latest Windows version that the Zig Standard Library is aware of
pub const latest = WindowsVersion.win10_20h1;
pub const latest = WindowsVersion.win10_fe;
/// Compared against build numbers reported by the runtime to distinguish win10 versions,
/// where 0x0A000000 + index corresponds to the WindowsVersion u32 value.
pub const known_win10_build_numbers = [_]u32{
10240, //win10
10240, //win10 aka win10_th1
10586, //win10_th2
14393, //win_rs1
15063, //win_rs2
16299, //win_rs3
17134, //win_rs4
17763, //win_rs5
18362, //win_19h1
19041, //win_20h1
14393, //win10_rs1
15063, //win10_rs2
16299, //win10_rs3
17134, //win10_rs4
17763, //win10_rs5
18362, //win10_19h1
18363, //win10_vb aka win10_19h2
19041, //win10_mn aka win10_20h1
19042, //win10_fe aka win10_20h2
};
/// Returns whether the first version `self` is newer (greater) than or equal to the second version `ver`.
pub fn isAtLeast(self: WindowsVersion, ver: WindowsVersion) bool {
return @enumToInt(self) >= @enumToInt(ver);
}
pub const Range = struct {
min: WindowsVersion,
max: WindowsVersion,

16
lib/std/zig/system/windows.zig
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@ -43,19 +43,3 @@ pub fn detectRuntimeVersion() WindowsVersion {
return @intToEnum(WindowsVersion, version);
}
/// Returns whether the target os versions are uniformly at least as new as the argument:
/// true/false if this holds for the entire target range, null if it only holds for some.
pub fn targetVersionIsAtLeast(requested_version: WindowsVersion) ?bool {
const requested = @enumToInt(requested_version);
const version_range = std.builtin.os.version_range.windows;
const target_min = @enumToInt(version_range.min);
const target_max = @enumToInt(version_range.max);
return if (target_max < requested) false else if (target_min >= requested) true else null;
}
/// Returns whether the runtime os version is at least as new as the argument.
pub fn runtimeVersionIsAtLeast(requested_version: WindowsVersion) bool {
return targetVersionIsAtLeast(requested_version) orelse
(@enumToInt(detectRuntimeVersion()) >= @enumToInt(requested_version));
}