Minimal ACL. but ugly.

acl_min.zig

// zig run acl_min.zig
pub const DWORD = c_ulong;
pub const HANDLE = ?*anyopaque;
pub const PVOID = ?*anyopaque;
pub const PSID = PVOID;
pub const PSECURITY_DESCRIPTOR = PVOID;
pub const enum__SE_OBJECT_TYPE = c_uint;
pub const SE_OBJECT_TYPE = enum__SE_OBJECT_TYPE;
pub const wchar_t = c_ushort;
pub const SE_FILE_OBJECT: c_int = 1;
pub const WCHAR = wchar_t;
pub const LPCWSTR = [*c]const WCHAR;
pub const BYTE = u8;
pub const WORD = c_ushort;
pub const struct__ACL = extern struct {
    AclRevision: BYTE = @import("std").mem.zeroes(BYTE),
    Sbz1: BYTE = @import("std").mem.zeroes(BYTE),
    AclSize: WORD = @import("std").mem.zeroes(WORD),
    AceCount: WORD = @import("std").mem.zeroes(WORD),
    Sbz2: WORD = @import("std").mem.zeroes(WORD),
};
pub const ACL = struct__ACL;
pub const PACL = [*c]ACL;
pub const LPVOID = ?*anyopaque;
pub const WINBOOL = c_int;
pub const SECURITY_INFORMATION = DWORD;
pub const struct__SECURITY_ATTRIBUTES = extern struct {
    nLength: DWORD = @import("std").mem.zeroes(DWORD),
    lpSecurityDescriptor: LPVOID = @import("std").mem.zeroes(LPVOID),
    bInheritHandle: WINBOOL = @import("std").mem.zeroes(WINBOOL),
};
pub const LPSECURITY_ATTRIBUTES = [*c]struct__SECURITY_ATTRIBUTES;

pub extern fn GetLastError() DWORD;
pub extern fn GetSecurityInfo(handle: HANDLE, ObjectType: SE_OBJECT_TYPE, SecurityInfo: SECURITY_INFORMATION, ppsidOwner: [*c]PSID, ppsidGroup: [*c]PSID, ppDacl: [*c]PACL, ppSacl: [*c]PACL, ppSecurityDescriptor: [*c]PSECURITY_DESCRIPTOR) DWORD;

const std = @import("std");

pub fn main() !void {
    var st: DWORD = 0;
    var pSidOwner: PSID = null;
    var pSD: PSECURITY_DESCRIPTOR = null;

    const tmpDir = std.testing.tmpDir;
    var tmp = tmpDir(.{});
    defer tmp.cleanup();
    const file_user = try tmp.dir.createFile("file_user", .{ .read = true });
    defer file_user.close();
    var file_user_h: ?std.fs.File.Handle = null;
    file_user_h = file_user.handle;

    st = GetSecurityInfo(file_user_h, @as(c_uint, @bitCast(SE_FILE_OBJECT)), @as(SECURITY_INFORMATION, @bitCast(@as(c_long, 1))), &pSidOwner, null, null, null, &pSD);

    if (st != @as(DWORD, @bitCast(@as(c_long, 0)))) {
        var dwErrorCode: DWORD = 0;
        dwErrorCode = GetLastError();
        std.debug.print("GetSecurityInfo error = {d}\n", .{ dwErrorCode });
    }
}