miri/shims/windows/

fs.rs

use std::fs::{self, Dir};
use std::io;
use std::io::SeekFrom;
use std::time::SystemTime;

use bitflags::bitflags;
use rustc_abi::Size;
use rustc_target::spec::Os;

use crate::shims::files::{DirHandle, FileHandle};
use crate::shims::windows::handle::{EvalContextExt as _, Handle};
use crate::*;

#[derive(Copy, Clone, Debug, PartialEq)]
enum CreationDisposition {
    CreateAlways,
    CreateNew,
    OpenAlways,
    OpenExisting,
    TruncateExisting,
}

impl CreationDisposition {
    fn new<'tcx>(
        value: u32,
        ecx: &mut MiriInterpCx<'tcx>,
    ) -> InterpResult<'tcx, CreationDisposition> {
        let create_always = ecx.eval_windows_u32("c", "CREATE_ALWAYS");
        let create_new = ecx.eval_windows_u32("c", "CREATE_NEW");
        let open_always = ecx.eval_windows_u32("c", "OPEN_ALWAYS");
        let open_existing = ecx.eval_windows_u32("c", "OPEN_EXISTING");
        let truncate_existing = ecx.eval_windows_u32("c", "TRUNCATE_EXISTING");

        let out = if value == create_always {
            CreationDisposition::CreateAlways
        } else if value == create_new {
            CreationDisposition::CreateNew
        } else if value == open_always {
            CreationDisposition::OpenAlways
        } else if value == open_existing {
            CreationDisposition::OpenExisting
        } else if value == truncate_existing {
            CreationDisposition::TruncateExisting
        } else {
            throw_unsup_format!("CreateFileW: Unsupported creation disposition: {value}");
        };
        interp_ok(out)
    }
}

bitflags! {
    #[derive(PartialEq)]
    struct FileAttributes: u32 {
        const ZERO = 0;
        const NORMAL = 1 << 0;
        /// This must be passed to allow getting directory handles. If not passed, we error on trying
        /// to open directories
        const BACKUP_SEMANTICS = 1 << 1;
        /// Open a reparse point as a regular file - this is basically similar to 'readlink' in Unix
        /// terminology. A reparse point is a file with custom logic when navigated to, of which
        /// a symlink is one specific example.
        const OPEN_REPARSE = 1 << 2;
    }
}

impl FileAttributes {
    fn new<'tcx>(
        mut value: u32,
        ecx: &mut MiriInterpCx<'tcx>,
    ) -> InterpResult<'tcx, FileAttributes> {
        let file_attribute_normal = ecx.eval_windows_u32("c", "FILE_ATTRIBUTE_NORMAL");
        let file_flag_backup_semantics = ecx.eval_windows_u32("c", "FILE_FLAG_BACKUP_SEMANTICS");
        let file_flag_open_reparse_point =
            ecx.eval_windows_u32("c", "FILE_FLAG_OPEN_REPARSE_POINT");

        let mut out = FileAttributes::ZERO;
        if value & file_flag_backup_semantics != 0 {
            value &= !file_flag_backup_semantics;
            out |= FileAttributes::BACKUP_SEMANTICS;
        }
        if value & file_flag_open_reparse_point != 0 {
            value &= !file_flag_open_reparse_point;
            out |= FileAttributes::OPEN_REPARSE;
        }
        if value & file_attribute_normal != 0 {
            value &= !file_attribute_normal;
            out |= FileAttributes::NORMAL;
        }

        if value != 0 {
            throw_unsup_format!("CreateFileW: Unsupported flags_and_attributes: {value}");
        }

        if out == FileAttributes::ZERO {
            // NORMAL is equivalent to 0. Avoid needing to check both cases by unifying the two.
            out = FileAttributes::NORMAL;
        }
        interp_ok(out)
    }
}

impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
#[allow(non_snake_case)]
pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
    fn CreateFileW(
        &mut self,
        file_name: &OpTy<'tcx>,            // LPCWSTR
        desired_access: &OpTy<'tcx>,       // DWORD
        share_mode: &OpTy<'tcx>,           // DWORD
        security_attributes: &OpTy<'tcx>,  // LPSECURITY_ATTRIBUTES
        creation_disposition: &OpTy<'tcx>, // DWORD
        flags_and_attributes: &OpTy<'tcx>, // DWORD
        template_file: &OpTy<'tcx>,        // HANDLE
    ) -> InterpResult<'tcx, Handle> {
        // ^ Returns HANDLE
        use CreationDisposition::*;

        let this = self.eval_context_mut();
        this.assert_target_os(Os::Windows, "CreateFileW");
        this.check_no_isolation("`CreateFileW`")?;

        // This function appears to always set the error to 0. This is important for some flag
        // combinations, which may set error code on success.
        this.set_last_error(IoError::Raw(Scalar::from_i32(0)))?;

        let file_name = this.read_path_from_wide_str(this.read_pointer(file_name)?)?;
        let mut desired_access = this.read_scalar(desired_access)?.to_u32()?;
        let share_mode = this.read_scalar(share_mode)?.to_u32()?;
        let security_attributes = this.read_pointer(security_attributes)?;
        let creation_disposition = this.read_scalar(creation_disposition)?.to_u32()?;
        let flags_and_attributes = this.read_scalar(flags_and_attributes)?.to_u32()?;
        let template_file = this.read_target_usize(template_file)?;

        let generic_read = this.eval_windows_u32("c", "GENERIC_READ");
        let generic_write = this.eval_windows_u32("c", "GENERIC_WRITE");

        let file_share_delete = this.eval_windows_u32("c", "FILE_SHARE_DELETE");
        let file_share_read = this.eval_windows_u32("c", "FILE_SHARE_READ");
        let file_share_write = this.eval_windows_u32("c", "FILE_SHARE_WRITE");

        let creation_disposition = CreationDisposition::new(creation_disposition, this)?;
        let attributes = FileAttributes::new(flags_and_attributes, this)?;

        if share_mode != (file_share_delete | file_share_read | file_share_write) {
            throw_unsup_format!("CreateFileW: Unsupported share mode: {share_mode}");
        }
        if !this.ptr_is_null(security_attributes)? {
            throw_unsup_format!("CreateFileW: Security attributes are not supported");
        }

        if attributes.contains(FileAttributes::OPEN_REPARSE) && creation_disposition == CreateAlways
        {
            throw_machine_stop!(TerminationInfo::Abort("Invalid CreateFileW argument combination: FILE_FLAG_OPEN_REPARSE_POINT with CREATE_ALWAYS".to_string()));
        }

        if template_file != 0 {
            throw_unsup_format!("CreateFileW: Template files are not supported");
        }

        // Parse desired_access
        let mut desired_read = false;
        if desired_access & generic_read != 0 {
            desired_read = true;
            desired_access &= !generic_read;
        }
        let mut desired_write = false;
        if desired_access & generic_write != 0 {
            desired_write = true;
            desired_access &= !generic_write;
        }

        if desired_access != 0 {
            throw_unsup_format!(
                "CreateFileW: Unsupported bits set for access mode: {desired_access:#x}"
            );
        }

        // We start a retry loop to deal with the `is_dir` and `exists_already` race, see below.
        // We add a retry counter to avoid infinite loops when things go wrong.
        let mut counter = 0u32;
        loop {
            if counter >= 100 {
                panic!(
                    "CreateFileW seems stuck in an infinite retry loop. \
                    If you can reproduce this, please file a bug."
                );
            }
            counter = counter.strict_add(1);

            // We need to know if the file is a directory to correctly open directory handles.
            // The standard library only lets us open something as a file or a directory, so
            // we check for that and then retry if we end up with the wrong thing.
            let is_dir = file_name.is_dir();

            // BACKUP_SEMANTICS is how Windows calls the act of opening a directory handle.
            if !attributes.contains(FileAttributes::BACKUP_SEMANTICS) && is_dir {
                this.set_last_error(IoError::WindowsError("ERROR_ACCESS_DENIED"))?;
                return interp_ok(Handle::Invalid);
            }

            if is_dir {
                // Open this as a directory.
                // FIXME: shouldn't we check `creation_disposition` here? We do know that it already
                // exists.
                let dir = match Dir::open(&file_name) {
                    Ok(dir) => dir,
                    Err(e) => {
                        if e.kind() == io::ErrorKind::NotADirectory {
                            // This changed from a directory to a file. Retry.
                            continue;
                        }
                        this.set_last_error(e)?;
                        return interp_ok(Handle::Invalid);
                    }
                };
                if !dir.metadata().unwrap().is_dir() {
                    // This changed from a directory to a file. Retry.
                    continue;
                }

                // Windows communicates information via the error code on success.
                if let CreateAlways | OpenAlways = creation_disposition {
                    this.set_last_error(IoError::WindowsError("ERROR_ALREADY_EXISTS"))?;
                }

                let fd_num = this.machine.fds.insert_new(DirHandle { dir });
                return interp_ok(Handle::File(fd_num));
            } else {
                // Per the documentation:
                // If the specified file exists and is writable, the function truncates the file,
                // the function succeeds, and last-error code is set to ERROR_ALREADY_EXISTS.
                // If the specified file does not exist and is a valid path, a new file is created,
                // the function succeeds, and the last-error code is set to zero.
                // https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew
                //
                // We check whether it exists before trying to open it. This is racy, but there
                // doesn't appear to be an std API that both succeeds whether or not a file already
                // exists and tells us whether it is new. So instead we will open the file in a way
                // that we can verify whether our guess is correct, and retry if it is not.
                let exists_already = file_name.exists();

                // Open this as a standard file.
                let mut options = fs::OpenOptions::new();
                options.read(desired_read);
                options.write(desired_write);
                match creation_disposition {
                    CreateAlways | OpenAlways => {
                        // We verify `exists_already`: if we expect it to already exist, we set no
                        // flag, thus failing if it doesn't exist. If we expect the file to not
                        // exist, we use `create_new` to fail if it does exist.
                        if !exists_already {
                            options.create_new(true);
                        }
                        if creation_disposition == CreateAlways {
                            options.truncate(true);
                        }
                    }
                    CreateNew => {
                        options.create_new(true);
                        // Per `create_new` documentation:
                        // The file must be opened with write or append access in order to create a new file.
                        // https://doc.rust-lang.org/std/fs/struct.OpenOptions.html#method.create_new
                        if !desired_write {
                            options.append(true);
                        }
                    }
                    OpenExisting => {
                        if !desired_read && !desired_write {
                            // Windows supports handles with no permissions. These allow things such as
                            // reading metadata, but not file content. This is used by `Path::metadata`.
                            // `std` does not support this. To ensure we behave correctly as often as
                            // possible, we open the file for reading and live with the fact that this
                            // might incorrectly return `PermissionDenied`.
                            // FIXME: We could probably use `OpenOptionsExt`? On a Unix host,
                            // `O_PATH` apparently can open files for metadata use only.
                            options.read(true);
                        }
                    }
                    TruncateExisting => {
                        options.truncate(true);
                    }
                }

                let file = match options.open(&file_name) {
                    Ok(file) => file,
                    Err(e) => {
                        let kind = e.kind();
                        if kind == io::ErrorKind::IsADirectory {
                            // This changed from a file to a directory. Retry.
                            continue;
                        }
                        if exists_already && kind == io::ErrorKind::NotFound {
                            // The file disappeared. Retry.
                            continue;
                        }
                        if !exists_already && kind == io::ErrorKind::AlreadyExists {
                            // The file got created by something else. Retry.
                            continue;
                        }
                        this.set_last_error(e)?;
                        return interp_ok(Handle::Invalid);
                    }
                };
                if file.metadata().unwrap().is_dir() {
                    // This changed from a file to a directory. Retry.
                    continue;
                }

                // Windows communicates information via the error code on success.
                if let CreateAlways | OpenAlways = creation_disposition
                    && exists_already
                {
                    this.set_last_error(IoError::WindowsError("ERROR_ALREADY_EXISTS"))?;
                }
                let fd_num = this.machine.fds.insert_new(FileHandle {
                    file,
                    writable: desired_write,
                    readable: desired_read,
                });
                return interp_ok(Handle::File(fd_num));
            }
        }
    }

    fn GetFileInformationByHandle(
        &mut self,
        file: &OpTy<'tcx>,             // HANDLE
        file_information: &OpTy<'tcx>, // LPBY_HANDLE_FILE_INFORMATION
    ) -> InterpResult<'tcx, Scalar> {
        // ^ Returns BOOL (i32 on Windows)
        let this = self.eval_context_mut();
        this.assert_target_os(Os::Windows, "GetFileInformationByHandle");
        this.check_no_isolation("`GetFileInformationByHandle`")?;

        let file = this.read_handle(file, "GetFileInformationByHandle")?;
        let file_information = this.deref_pointer_as(
            file_information,
            this.windows_ty_layout("BY_HANDLE_FILE_INFORMATION"),
        )?;

        let Handle::File(fd_num) = file else { this.invalid_handle("GetFileInformationByHandle")? };

        let Some(desc) = this.machine.fds.get(fd_num) else {
            this.invalid_handle("GetFileInformationByHandle")?
        };

        let metadata = match desc.metadata()? {
            Either::Left(Ok(meta)) => meta,
            Either::Left(Err(e)) => {
                this.set_last_error(e)?;
                return interp_ok(this.eval_windows("c", "FALSE"));
            }
            Either::Right(_mode) =>
                throw_unsup_format!(
                    "`GetFileInformationByHandle` is not supported on non-file-backed handles"
                ),
        };

        let size = metadata.len();

        let file_type = metadata.file_type();
        let attributes = if file_type.is_dir() {
            this.eval_windows_u32("c", "FILE_ATTRIBUTE_DIRECTORY")
        } else if file_type.is_file() {
            this.eval_windows_u32("c", "FILE_ATTRIBUTE_NORMAL")
        } else {
            this.eval_windows_u32("c", "FILE_ATTRIBUTE_DEVICE")
        };

        // Per the Windows documentation:
        // "If the underlying file system does not support the [...] time, this member is zero (0)."
        // https://learn.microsoft.com/en-us/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information
        let created = extract_windows_epoch(this, metadata.created())?.unwrap_or((0, 0));
        let accessed = extract_windows_epoch(this, metadata.accessed())?.unwrap_or((0, 0));
        let written = extract_windows_epoch(this, metadata.modified())?.unwrap_or((0, 0));

        this.write_int_fields_named(&[("dwFileAttributes", attributes.into())], &file_information)?;
        write_filetime_field(this, &file_information, "ftCreationTime", created)?;
        write_filetime_field(this, &file_information, "ftLastAccessTime", accessed)?;
        write_filetime_field(this, &file_information, "ftLastWriteTime", written)?;
        this.write_int_fields_named(
            &[
                ("dwVolumeSerialNumber", 0),
                ("nFileSizeHigh", (size >> 32).into()),
                ("nFileSizeLow", (size & 0xFFFFFFFF).into()),
                ("nNumberOfLinks", 1),
                ("nFileIndexHigh", 0),
                ("nFileIndexLow", 0),
            ],
            &file_information,
        )?;

        interp_ok(this.eval_windows("c", "TRUE"))
    }

    fn SetFileInformationByHandle(
        &mut self,
        file: &OpTy<'tcx>,             // HANDLE
        class: &OpTy<'tcx>,            // FILE_INFO_BY_HANDLE_CLASS
        file_information: &OpTy<'tcx>, // LPVOID
        buffer_size: &OpTy<'tcx>,      // DWORD
    ) -> InterpResult<'tcx, Scalar> {
        // ^ Returns BOOL (i32 on Windows)
        let this = self.eval_context_mut();
        this.assert_target_os(Os::Windows, "SetFileInformationByHandle");
        this.check_no_isolation("`SetFileInformationByHandle`")?;

        let class = this.read_scalar(class)?.to_u32()?;
        let buffer_size = this.read_scalar(buffer_size)?.to_u32()?;
        let file_information = this.read_pointer(file_information)?;
        this.check_ptr_access(
            file_information,
            Size::from_bytes(buffer_size),
            CheckInAllocMsg::MemoryAccess,
        )?;

        let file = this.read_handle(file, "SetFileInformationByHandle")?;
        let Handle::File(fd_num) = file else { this.invalid_handle("SetFileInformationByHandle")? };
        let Some(desc) = this.machine.fds.get(fd_num) else {
            this.invalid_handle("SetFileInformationByHandle")?
        };
        let file = desc.downcast::<FileHandle>().ok_or_else(|| {
            err_unsup_format!(
                "`SetFileInformationByHandle` is only supported on file-backed file descriptors"
            )
        })?;

        if class == this.eval_windows_u32("c", "FileEndOfFileInfo") {
            let place = this
                .ptr_to_mplace(file_information, this.windows_ty_layout("FILE_END_OF_FILE_INFO"));
            let new_len =
                this.read_scalar(&this.project_field_named(&place, "EndOfFile")?)?.to_i64()?;
            match file.file.set_len(new_len.try_into().unwrap()) {
                Ok(_) => interp_ok(this.eval_windows("c", "TRUE")),
                Err(e) => {
                    this.set_last_error(e)?;
                    interp_ok(this.eval_windows("c", "FALSE"))
                }
            }
        } else if class == this.eval_windows_u32("c", "FileAllocationInfo") {
            // On Windows, files are somewhat similar to a `Vec` in that they have a separate
            // "length" (called "EOF position") and "capacity" (called "allocation size").
            // Growing the allocation size is largely a performance hint which we can
            // ignore -- it can also be directly queried, but we currently do not support that.
            // So we only need to do something if this operation shrinks the allocation size
            // so far that it affects the EOF position.
            let place = this
                .ptr_to_mplace(file_information, this.windows_ty_layout("FILE_ALLOCATION_INFO"));
            let new_alloc_size: u64 = this
                .read_scalar(&this.project_field_named(&place, "AllocationSize")?)?
                .to_i64()?
                .try_into()
                .unwrap();
            let old_len = match file.file.metadata() {
                Ok(m) => m.len(),
                Err(e) => {
                    this.set_last_error(e)?;
                    return interp_ok(this.eval_windows("c", "FALSE"));
                }
            };
            if new_alloc_size < old_len {
                match file.file.set_len(new_alloc_size) {
                    Ok(_) => interp_ok(this.eval_windows("c", "TRUE")),
                    Err(e) => {
                        this.set_last_error(e)?;
                        interp_ok(this.eval_windows("c", "FALSE"))
                    }
                }
            } else {
                interp_ok(this.eval_windows("c", "TRUE"))
            }
        } else {
            throw_unsup_format!(
                "SetFileInformationByHandle: Unsupported `FileInformationClass` value {}",
                class
            )
        }
    }

    fn FlushFileBuffers(
        &mut self,
        file: &OpTy<'tcx>, // HANDLE
    ) -> InterpResult<'tcx, Scalar> {
        // ^ returns BOOL (i32 on Windows)
        let this = self.eval_context_mut();
        this.assert_target_os(Os::Windows, "FlushFileBuffers");

        let file = this.read_handle(file, "FlushFileBuffers")?;
        let Handle::File(fd_num) = file else { this.invalid_handle("FlushFileBuffers")? };
        let Some(desc) = this.machine.fds.get(fd_num) else {
            this.invalid_handle("FlushFileBuffers")?
        };
        let file = desc.downcast::<FileHandle>().ok_or_else(|| {
            err_unsup_format!(
                "`FlushFileBuffers` is only supported on file-backed file descriptors"
            )
        })?;

        if !file.writable {
            this.set_last_error(IoError::WindowsError("ERROR_ACCESS_DENIED"))?;
            return interp_ok(this.eval_windows("c", "FALSE"));
        }

        match file.file.sync_all() {
            Ok(_) => interp_ok(this.eval_windows("c", "TRUE")),
            Err(e) => {
                this.set_last_error(e)?;
                interp_ok(this.eval_windows("c", "FALSE"))
            }
        }
    }

    fn MoveFileExW(
        &mut self,
        existing_name: &OpTy<'tcx>,
        new_name: &OpTy<'tcx>,
        flags: &OpTy<'tcx>,
    ) -> InterpResult<'tcx, Scalar> {
        let this = self.eval_context_mut();

        let existing_name = this.read_path_from_wide_str(this.read_pointer(existing_name)?)?;
        let new_name = this.read_path_from_wide_str(this.read_pointer(new_name)?)?;

        let flags = this.read_scalar(flags)?.to_u32()?;

        // Flag to indicate whether we should replace an existing file.
        // https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-movefileexw
        let movefile_replace_existing = this.eval_windows_u32("c", "MOVEFILE_REPLACE_EXISTING");

        if flags != movefile_replace_existing {
            throw_unsup_format!("MoveFileExW: Unsupported `dwFlags` value {}", flags);
        }

        match std::fs::rename(existing_name, new_name) {
            Ok(_) => interp_ok(this.eval_windows("c", "TRUE")),
            Err(e) => {
                this.set_last_error(e)?;
                interp_ok(this.eval_windows("c", "FALSE"))
            }
        }
    }

    fn DeleteFileW(
        &mut self,
        file_name: &OpTy<'tcx>, // LPCWSTR
    ) -> InterpResult<'tcx, Scalar> {
        // ^ Returns BOOL (i32 on Windows)
        let this = self.eval_context_mut();
        this.assert_target_os(Os::Windows, "DeleteFileW");
        this.check_no_isolation("`DeleteFileW`")?;

        let file_name = this.read_path_from_wide_str(this.read_pointer(file_name)?)?;
        match std::fs::remove_file(file_name) {
            Ok(_) => interp_ok(this.eval_windows("c", "TRUE")),
            Err(e) => {
                this.set_last_error(e)?;
                interp_ok(this.eval_windows("c", "FALSE"))
            }
        }
    }

    fn NtWriteFile(
        &mut self,
        handle: &OpTy<'tcx>,          // HANDLE
        event: &OpTy<'tcx>,           // HANDLE
        apc_routine: &OpTy<'tcx>,     // PIO_APC_ROUTINE
        apc_ctx: &OpTy<'tcx>,         // PVOID
        io_status_block: &OpTy<'tcx>, // PIO_STATUS_BLOCK
        buf: &OpTy<'tcx>,             // PVOID
        n: &OpTy<'tcx>,               // ULONG
        byte_offset: &OpTy<'tcx>,     // PLARGE_INTEGER
        key: &OpTy<'tcx>,             // PULONG
        dest: &MPlaceTy<'tcx>,        // return type: NTSTATUS
    ) -> InterpResult<'tcx, ()> {
        let this = self.eval_context_mut();
        let handle = this.read_handle(handle, "NtWriteFile")?;
        let event = this.read_handle(event, "NtWriteFile")?;
        let apc_routine = this.read_pointer(apc_routine)?;
        let apc_ctx = this.read_pointer(apc_ctx)?;
        let buf = this.read_pointer(buf)?;
        let count = this.read_scalar(n)?.to_u32()?;
        let byte_offset = this.read_target_usize(byte_offset)?; // is actually a pointer, but we only support null
        let key = this.read_pointer(key)?;
        let io_status_block =
            this.deref_pointer_as(io_status_block, this.windows_ty_layout("IO_STATUS_BLOCK"))?;

        if event != Handle::Null {
            throw_unsup_format!(
                "`NtWriteFile` `Event` parameter is non-null, which is unsupported"
            );
        }

        if !this.ptr_is_null(apc_routine)? {
            throw_unsup_format!(
                "`NtWriteFile` `ApcRoutine` parameter is non-null, which is unsupported"
            );
        }

        if !this.ptr_is_null(apc_ctx)? {
            throw_unsup_format!(
                "`NtWriteFile` `ApcContext` parameter is non-null, which is unsupported"
            );
        }

        if byte_offset != 0 {
            throw_unsup_format!(
                "`NtWriteFile` `ByteOffset` parameter is non-null, which is unsupported"
            );
        }

        if !this.ptr_is_null(key)? {
            throw_unsup_format!("`NtWriteFile` `Key` parameter is non-null, which is unsupported");
        }

        let Handle::File(fd) = handle else { this.invalid_handle("NtWriteFile")? };

        let Some(desc) = this.machine.fds.get(fd) else { this.invalid_handle("NtWriteFile")? };

        // Windows writes the output code to IO_STATUS_BLOCK.Status, and number of bytes written
        // to IO_STATUS_BLOCK.Information.
        // The status block value and the returned value don't need to match - but
        // for the cases implemented by miri so far, we can choose to decide that they do.
        let io_status = {
            let anon = this.project_field_named(&io_status_block, "Anonymous")?;
            this.project_field_named(&anon, "Status")?
        };
        let io_status_info = this.project_field_named(&io_status_block, "Information")?;

        // It seems like short writes are not a thing on Windows, so we don't truncate `count` here.
        // FIXME: if we are on a Unix host, short host writes are still visible to the program!

        let finish = {
            let io_status = io_status.clone();
            let io_status_info = io_status_info.clone();
            let dest = dest.clone();
            callback!(
                @capture<'tcx> {
                    count: u32,
                    io_status: MPlaceTy<'tcx>,
                    io_status_info: MPlaceTy<'tcx>,
                    dest: MPlaceTy<'tcx>,
                }
                |this, result: Result<usize, IoError>| {
                    match result {
                        Ok(read_size) => {
                            assert!(read_size <= count.try_into().unwrap());
                            // This must fit since `count` fits.
                            this.write_int(u64::try_from(read_size).unwrap(), &io_status_info)?;
                            this.write_int(0, &io_status)?;
                            this.write_int(0, &dest)
                        }
                        Err(e) => {
                            this.write_int(0, &io_status_info)?;
                            let status = e.into_ntstatus();
                            this.write_int(status, &io_status)?;
                            this.write_int(status, &dest)
                        }
                }}
            )
        };
        desc.write(this.machine.communicate(), buf, count.try_into().unwrap(), this, finish)?;

        // Return status is written to `dest` and `io_status_block` on callback completion.
        interp_ok(())
    }

    fn NtReadFile(
        &mut self,
        handle: &OpTy<'tcx>,          // HANDLE
        event: &OpTy<'tcx>,           // HANDLE
        apc_routine: &OpTy<'tcx>,     // PIO_APC_ROUTINE
        apc_ctx: &OpTy<'tcx>,         // PVOID
        io_status_block: &OpTy<'tcx>, // PIO_STATUS_BLOCK
        buf: &OpTy<'tcx>,             // PVOID
        n: &OpTy<'tcx>,               // ULONG
        byte_offset: &OpTy<'tcx>,     // PLARGE_INTEGER
        key: &OpTy<'tcx>,             // PULONG
        dest: &MPlaceTy<'tcx>,        // return type: NTSTATUS
    ) -> InterpResult<'tcx, ()> {
        let this = self.eval_context_mut();
        let handle = this.read_handle(handle, "NtReadFile")?;
        let event = this.read_handle(event, "NtReadFile")?;
        let apc_routine = this.read_pointer(apc_routine)?;
        let apc_ctx = this.read_pointer(apc_ctx)?;
        let buf = this.read_pointer(buf)?;
        let count = this.read_scalar(n)?.to_u32()?;
        let byte_offset = this.read_target_usize(byte_offset)?; // is actually a pointer, but we only support null
        let key = this.read_pointer(key)?;
        let io_status_block =
            this.deref_pointer_as(io_status_block, this.windows_ty_layout("IO_STATUS_BLOCK"))?;

        if event != Handle::Null {
            throw_unsup_format!("`NtReadFile` `Event` parameter is non-null, which is unsupported");
        }

        if !this.ptr_is_null(apc_routine)? {
            throw_unsup_format!(
                "`NtReadFile` `ApcRoutine` parameter is non-null, which is unsupported"
            );
        }

        if !this.ptr_is_null(apc_ctx)? {
            throw_unsup_format!(
                "`NtReadFile` `ApcContext` parameter is non-null, which is unsupported"
            );
        }

        if byte_offset != 0 {
            throw_unsup_format!(
                "`NtReadFile` `ByteOffset` parameter is non-null, which is unsupported"
            );
        }

        if !this.ptr_is_null(key)? {
            throw_unsup_format!("`NtReadFile` `Key` parameter is non-null, which is unsupported");
        }

        // See NtWriteFile above for commentary on this
        let io_status = {
            let anon = this.project_field_named(&io_status_block, "Anonymous")?;
            this.project_field_named(&anon, "Status")?
        };
        let io_status_info = this.project_field_named(&io_status_block, "Information")?;

        let Handle::File(fd) = handle else { this.invalid_handle("NtWriteFile")? };

        let Some(desc) = this.machine.fds.get(fd) else { this.invalid_handle("NtReadFile")? };

        // It seems like short reads are not a thing on Windows, so we don't truncate `count` here.
        // FIXME: if we are on a Unix host, short host reads are still visible to the program!

        let finish = {
            let io_status = io_status.clone();
            let io_status_info = io_status_info.clone();
            let dest = dest.clone();
            callback!(
                @capture<'tcx> {
                    count: u32,
                    io_status: MPlaceTy<'tcx>,
                    io_status_info: MPlaceTy<'tcx>,
                    dest: MPlaceTy<'tcx>,
                }
                |this, result: Result<usize, IoError>| {
                    match result {
                        Ok(read_size) => {
                            assert!(read_size <= count.try_into().unwrap());
                            // This must fit since `count` fits.
                            this.write_int(u64::try_from(read_size).unwrap(), &io_status_info)?;
                            this.write_int(0, &io_status)?;
                            this.write_int(0, &dest)
                        }
                        Err(e) => {
                            this.write_int(0, &io_status_info)?;
                            let status = e.into_ntstatus();
                            this.write_int(status, &io_status)?;
                            this.write_int(status, &dest)
                        }
                }}
            )
        };
        desc.read(this.machine.communicate(), buf, count.try_into().unwrap(), this, finish)?;

        // See NtWriteFile for commentary on this
        interp_ok(())
    }

    fn SetFilePointerEx(
        &mut self,
        file: &OpTy<'tcx>,         // HANDLE
        dist_to_move: &OpTy<'tcx>, // LARGE_INTEGER
        new_fp: &OpTy<'tcx>,       // PLARGE_INTEGER
        move_method: &OpTy<'tcx>,  // DWORD
    ) -> InterpResult<'tcx, Scalar> {
        // ^ Returns BOOL (i32 on Windows)
        let this = self.eval_context_mut();
        let file = this.read_handle(file, "SetFilePointerEx")?;
        let dist_to_move = this.read_scalar(dist_to_move)?.to_i64()?;
        let new_fp_ptr = this.read_pointer(new_fp)?;
        let move_method = this.read_scalar(move_method)?.to_u32()?;

        let Handle::File(fd) = file else { this.invalid_handle("SetFilePointerEx")? };

        let Some(desc) = this.machine.fds.get(fd) else {
            throw_unsup_format!("`SetFilePointerEx` is only supported on file backed handles");
        };

        let file_begin = this.eval_windows_u32("c", "FILE_BEGIN");
        let file_current = this.eval_windows_u32("c", "FILE_CURRENT");
        let file_end = this.eval_windows_u32("c", "FILE_END");

        let seek = if move_method == file_begin {
            SeekFrom::Start(dist_to_move.try_into().unwrap())
        } else if move_method == file_current {
            SeekFrom::Current(dist_to_move)
        } else if move_method == file_end {
            SeekFrom::End(dist_to_move)
        } else {
            throw_unsup_format!("Invalid move method: {move_method}")
        };

        match desc.seek(this.machine.communicate(), seek)? {
            Ok(n) => {
                if !this.ptr_is_null(new_fp_ptr)? {
                    this.write_scalar(
                        Scalar::from_i64(n.try_into().unwrap()),
                        &this.deref_pointer_as(new_fp, this.machine.layouts.i64)?,
                    )?;
                }
                interp_ok(this.eval_windows("c", "TRUE"))
            }
            Err(e) => {
                this.set_last_error(e)?;
                interp_ok(this.eval_windows("c", "FALSE"))
            }
        }
    }
}

/// Windows FILETIME is measured in 100-nanosecs since 1601
fn extract_windows_epoch<'tcx>(
    ecx: &MiriInterpCx<'tcx>,
    time: io::Result<SystemTime>,
) -> InterpResult<'tcx, Option<(u32, u32)>> {
    match time.ok() {
        Some(time) => {
            let duration = ecx.system_time_since_windows_epoch(&time)?;
            let duration_ticks = ecx.windows_ticks_for(duration)?;
            #[expect(clippy::as_conversions)]
            interp_ok(Some((duration_ticks as u32, (duration_ticks >> 32) as u32)))
        }
        None => interp_ok(None),
    }
}

fn write_filetime_field<'tcx>(
    cx: &mut MiriInterpCx<'tcx>,
    val: &MPlaceTy<'tcx>,
    name: &str,
    (low, high): (u32, u32),
) -> InterpResult<'tcx> {
    cx.write_int_fields_named(
        &[("dwLowDateTime", low.into()), ("dwHighDateTime", high.into())],
        &cx.project_field_named(val, name)?,
    )
}