// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license. use std::borrow::Cow; use std::collections::BTreeMap; use std::collections::HashMap; use std::collections::VecDeque; use std::env::current_exe; use std::ffi::OsString; use std::fs; use std::fs::File; use std::future::Future; use std::io::ErrorKind; use std::io::Read; use std::io::Seek; use std::io::SeekFrom; use std::io::Write; use std::ops::Range; use std::path::Path; use std::path::PathBuf; use std::process::Command; use std::sync::Arc; use deno_ast::MediaType; use deno_ast::ModuleSpecifier; use deno_config::workspace::PackageJsonDepResolution; use deno_config::workspace::ResolverWorkspaceJsrPackage; use deno_config::workspace::Workspace; use deno_config::workspace::WorkspaceResolver; use deno_core::anyhow::bail; use deno_core::anyhow::Context; use deno_core::error::AnyError; use deno_core::futures::io::AllowStdIo; use deno_core::futures::AsyncReadExt; use deno_core::futures::AsyncSeekExt; use deno_core::serde_json; use deno_core::url::Url; use deno_graph::source::RealFileSystem; use deno_graph::ModuleGraph; use deno_npm::resolution::SerializedNpmResolutionSnapshot; use deno_npm::resolution::SerializedNpmResolutionSnapshotPackage; use deno_npm::resolution::ValidSerializedNpmResolutionSnapshot; use deno_npm::NpmPackageId; use deno_npm::NpmSystemInfo; use deno_runtime::deno_fs; use deno_runtime::deno_fs::FileSystem; use deno_runtime::deno_fs::RealFs; use deno_runtime::deno_io::fs::FsError; use deno_runtime::deno_node::PackageJson; use deno_semver::npm::NpmVersionReqParseError; use deno_semver::package::PackageReq; use deno_semver::Version; use deno_semver::VersionReqSpecifierParseError; use indexmap::IndexMap; use log::Level; use serde::Deserialize; use serde::Serialize; use crate::args::CaData; use crate::args::CliOptions; use crate::args::CompileFlags; use crate::args::NpmInstallDepsProvider; use crate::args::PermissionFlags; use crate::args::UnstableConfig; use crate::cache::DenoDir; use crate::emit::Emitter; use crate::file_fetcher::FileFetcher; use crate::http_util::HttpClientProvider; use crate::npm::CliNpmResolver; use crate::npm::InnerCliNpmResolverRef; use crate::shared::ReleaseChannel; use crate::standalone::virtual_fs::VfsEntry; use crate::util::archive; use crate::util::fs::canonicalize_path_maybe_not_exists; use crate::util::progress_bar::ProgressBar; use crate::util::progress_bar::ProgressBarStyle; use super::file_system::DenoCompileFileSystem; use super::serialization::deserialize_binary_data_section; use super::serialization::serialize_binary_data_section; use super::serialization::DenoCompileModuleData; use super::serialization::DeserializedDataSection; use super::serialization::RemoteModulesStore; use super::serialization::RemoteModulesStoreBuilder; use super::virtual_fs::FileBackedVfs; use super::virtual_fs::VfsBuilder; use super::virtual_fs::VfsRoot; use super::virtual_fs::VirtualDirectory; /// A URL that can be designated as the base for relative URLs. /// /// After creation, this URL may be used to get the key for a /// module in the binary. #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] pub struct StandaloneRelativeFileBaseUrl<'a>(&'a Url); impl<'a> From<&'a Url> for StandaloneRelativeFileBaseUrl<'a> { fn from(url: &'a Url) -> Self { Self(url) } } impl<'a> StandaloneRelativeFileBaseUrl<'a> { pub fn new(url: &'a Url) -> Self { debug_assert_eq!(url.scheme(), "file"); Self(url) } /// Gets the module map key of the provided specifier. /// /// * Descendant file specifiers will be made relative to the base. /// * Non-descendant file specifiers will stay as-is (absolute). /// * Non-file specifiers will stay as-is. pub fn specifier_key<'b>(&self, target: &'b Url) -> Cow<'b, str> { if target.scheme() != "file" { return Cow::Borrowed(target.as_str()); } match self.0.make_relative(target) { Some(relative) => { if relative.starts_with("../") { Cow::Borrowed(target.as_str()) } else { Cow::Owned(relative) } } None => Cow::Borrowed(target.as_str()), } } pub fn inner(&self) -> &Url { self.0 } } #[derive(Deserialize, Serialize)] pub enum NodeModules { Managed { /// Relative path for the node_modules directory in the vfs. node_modules_dir: Option, }, Byonm { root_node_modules_dir: Option, }, } #[derive(Deserialize, Serialize)] pub struct SerializedWorkspaceResolverImportMap { pub specifier: String, pub json: String, } #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)] pub struct SerializedResolverWorkspaceJsrPackage { pub relative_base: String, pub name: String, pub version: Option, pub exports: IndexMap, } #[derive(Deserialize, Serialize)] pub struct SerializedWorkspaceResolver { pub import_map: Option, pub jsr_pkgs: Vec, pub package_jsons: BTreeMap, pub pkg_json_resolution: PackageJsonDepResolution, } // Note: Don't use hashmaps/hashsets. Ensure the serialization // is deterministic. #[derive(Deserialize, Serialize)] pub struct Metadata { pub argv: Vec, pub seed: Option, pub permissions: PermissionFlags, pub location: Option, pub v8_flags: Vec, pub log_level: Option, pub ca_stores: Option>, pub ca_data: Option>, pub unsafely_ignore_certificate_errors: Option>, pub env_vars_from_env_file: IndexMap, pub workspace_resolver: SerializedWorkspaceResolver, pub entrypoint_key: String, pub node_modules: Option, pub unstable_config: UnstableConfig, } fn write_binary_bytes( mut file_writer: File, original_bin: Vec, metadata: &Metadata, npm_snapshot: Option, remote_modules: &RemoteModulesStoreBuilder, vfs: VfsBuilder, compile_flags: &CompileFlags, ) -> Result<(), AnyError> { let data_section_bytes = serialize_binary_data_section(metadata, npm_snapshot, remote_modules, vfs)?; let target = compile_flags.resolve_target(); if target.contains("linux") { libsui::Elf::new(&original_bin).append( "d3n0l4nd", &data_section_bytes, &mut file_writer, )?; } else if target.contains("windows") { let mut pe = libsui::PortableExecutable::from(&original_bin)?; if let Some(icon) = compile_flags.icon.as_ref() { let icon = std::fs::read(icon)?; pe = pe.set_icon(&icon)?; } pe.write_resource("d3n0l4nd", data_section_bytes)? .build(&mut file_writer)?; } else if target.contains("darwin") { libsui::Macho::from(original_bin)? .write_section("d3n0l4nd", data_section_bytes)? .build_and_sign(&mut file_writer)?; } Ok(()) } pub fn is_standalone_binary(exe_path: &Path) -> bool { let Ok(data) = std::fs::read(exe_path) else { return false; }; libsui::utils::is_elf(&data) || libsui::utils::is_pe(&data) || libsui::utils::is_macho(&data) } pub struct StandaloneData { pub fs: Arc, pub metadata: Metadata, pub modules: StandaloneModules, pub npm_snapshot: Option, pub root_path: PathBuf, pub vfs: Arc, } pub struct StandaloneModules { remote_modules: RemoteModulesStore, vfs: Arc, } impl StandaloneModules { pub fn resolve_specifier<'a>( &'a self, specifier: &'a ModuleSpecifier, ) -> Result, AnyError> { if specifier.scheme() == "file" { Ok(Some(specifier)) } else { self.remote_modules.resolve_specifier(specifier) } } pub fn read<'a>( &'a self, specifier: &'a ModuleSpecifier, ) -> Result>, AnyError> { if specifier.scheme() == "file" { let path = deno_path_util::url_to_file_path(specifier)?; let bytes = match self.vfs.file_entry(&path) { Ok(entry) => self.vfs.read_file_all(entry)?, Err(err) if err.kind() == ErrorKind::NotFound => { let bytes = match RealFs.read_file_sync(&path, None) { Ok(bytes) => bytes, Err(FsError::Io(err)) if err.kind() == ErrorKind::NotFound => { return Ok(None) } Err(err) => return Err(err.into()), }; Cow::Owned(bytes) } Err(err) => return Err(err.into()), }; Ok(Some(DenoCompileModuleData { media_type: MediaType::from_specifier(specifier), specifier, data: bytes, })) } else { self.remote_modules.read(specifier) } } } /// This function will try to run this binary as a standalone binary /// produced by `deno compile`. It determines if this is a standalone /// binary by skipping over the trailer width at the end of the file, /// then checking for the magic trailer string `d3n0l4nd`. If found, /// the bundle is executed. If not, this function exits with `Ok(None)`. pub fn extract_standalone( cli_args: Cow>, ) -> Result, AnyError> { let Some(data) = libsui::find_section("d3n0l4nd") else { return Ok(None); }; let DeserializedDataSection { mut metadata, npm_snapshot, remote_modules, mut vfs_dir, vfs_files_data, } = match deserialize_binary_data_section(data)? { Some(data_section) => data_section, None => return Ok(None), }; let root_path = { let maybe_current_exe = std::env::current_exe().ok(); let current_exe_name = maybe_current_exe .as_ref() .and_then(|p| p.file_name()) .map(|p| p.to_string_lossy()) // should never happen .unwrap_or_else(|| Cow::Borrowed("binary")); std::env::temp_dir().join(format!("deno-compile-{}", current_exe_name)) }; let cli_args = cli_args.into_owned(); metadata.argv.reserve(cli_args.len() - 1); for arg in cli_args.into_iter().skip(1) { metadata.argv.push(arg.into_string().unwrap()); } let vfs = { // align the name of the directory with the root dir vfs_dir.name = root_path.file_name().unwrap().to_string_lossy().to_string(); let fs_root = VfsRoot { dir: vfs_dir, root_path: root_path.clone(), start_file_offset: 0, }; Arc::new(FileBackedVfs::new(Cow::Borrowed(vfs_files_data), fs_root)) }; let fs: Arc = Arc::new(DenoCompileFileSystem::new(vfs.clone())); Ok(Some(StandaloneData { fs, metadata, modules: StandaloneModules { remote_modules, vfs: vfs.clone(), }, npm_snapshot, root_path, vfs, })) } pub struct DenoCompileBinaryWriter<'a> { deno_dir: &'a DenoDir, emitter: &'a Emitter, file_fetcher: &'a FileFetcher, http_client_provider: &'a HttpClientProvider, npm_resolver: &'a dyn CliNpmResolver, workspace_resolver: &'a WorkspaceResolver, npm_system_info: NpmSystemInfo, } impl<'a> DenoCompileBinaryWriter<'a> { #[allow(clippy::too_many_arguments)] pub fn new( deno_dir: &'a DenoDir, emitter: &'a Emitter, file_fetcher: &'a FileFetcher, http_client_provider: &'a HttpClientProvider, npm_resolver: &'a dyn CliNpmResolver, workspace_resolver: &'a WorkspaceResolver, npm_system_info: NpmSystemInfo, ) -> Self { Self { deno_dir, emitter, file_fetcher, http_client_provider, npm_resolver, workspace_resolver, npm_system_info, } } pub async fn write_bin( &self, writer: File, graph: &ModuleGraph, root_dir_url: StandaloneRelativeFileBaseUrl<'_>, entrypoint: &ModuleSpecifier, compile_flags: &CompileFlags, cli_options: &CliOptions, ) -> Result<(), AnyError> { // Select base binary based on target let mut original_binary = self.get_base_binary(compile_flags).await?; if compile_flags.no_terminal { let target = compile_flags.resolve_target(); if !target.contains("windows") { bail!( "The `--no-terminal` flag is only available when targeting Windows (current: {})", target, ) } set_windows_binary_to_gui(&mut original_binary)?; } if compile_flags.icon.is_some() { let target = compile_flags.resolve_target(); if !target.contains("windows") { bail!( "The `--icon` flag is only available when targeting Windows (current: {})", target, ) } } self .write_standalone_binary( writer, original_binary, graph, root_dir_url, entrypoint, cli_options, compile_flags, ) .await } async fn get_base_binary( &self, compile_flags: &CompileFlags, ) -> Result, AnyError> { // Used for testing. // // Phase 2 of the 'min sized' deno compile RFC talks // about adding this as a flag. if let Some(path) = std::env::var_os("DENORT_BIN") { return std::fs::read(&path).with_context(|| { format!("Could not find denort at '{}'", path.to_string_lossy()) }); } let target = compile_flags.resolve_target(); let binary_name = format!("denort-{target}.zip"); let binary_path_suffix = match crate::version::DENO_VERSION_INFO.release_channel { ReleaseChannel::Canary => { format!( "canary/{}/{}", crate::version::DENO_VERSION_INFO.git_hash, binary_name ) } _ => { format!("release/v{}/{}", env!("CARGO_PKG_VERSION"), binary_name) } }; let download_directory = self.deno_dir.dl_folder_path(); let binary_path = download_directory.join(&binary_path_suffix); if !binary_path.exists() { self .download_base_binary(&download_directory, &binary_path_suffix) .await?; } let archive_data = std::fs::read(binary_path)?; let temp_dir = tempfile::TempDir::new()?; let base_binary_path = archive::unpack_into_dir(archive::UnpackArgs { exe_name: "denort", archive_name: &binary_name, archive_data: &archive_data, is_windows: target.contains("windows"), dest_path: temp_dir.path(), })?; let base_binary = std::fs::read(base_binary_path)?; drop(temp_dir); // delete the temp dir Ok(base_binary) } async fn download_base_binary( &self, output_directory: &Path, binary_path_suffix: &str, ) -> Result<(), AnyError> { let download_url = format!("https://dl.deno.land/{binary_path_suffix}"); let maybe_bytes = { let progress_bars = ProgressBar::new(ProgressBarStyle::DownloadBars); let progress = progress_bars.update(&download_url); self .http_client_provider .get_or_create()? .download_with_progress_and_retries( download_url.parse()?, None, &progress, ) .await? }; let bytes = match maybe_bytes { Some(bytes) => bytes, None => { log::info!("Download could not be found, aborting"); std::process::exit(1) } }; std::fs::create_dir_all(output_directory)?; let output_path = output_directory.join(binary_path_suffix); std::fs::create_dir_all(output_path.parent().unwrap())?; tokio::fs::write(output_path, bytes).await?; Ok(()) } /// This functions creates a standalone deno binary by appending a bundle /// and magic trailer to the currently executing binary. #[allow(clippy::too_many_arguments)] async fn write_standalone_binary( &self, writer: File, original_bin: Vec, graph: &ModuleGraph, root_dir_url: StandaloneRelativeFileBaseUrl<'_>, entrypoint: &ModuleSpecifier, cli_options: &CliOptions, compile_flags: &CompileFlags, ) -> Result<(), AnyError> { let ca_data = match cli_options.ca_data() { Some(CaData::File(ca_file)) => Some( std::fs::read(ca_file) .with_context(|| format!("Reading: {ca_file}"))?, ), Some(CaData::Bytes(bytes)) => Some(bytes.clone()), None => None, }; let root_path = root_dir_url.inner().to_file_path().unwrap(); let (maybe_npm_vfs, node_modules, npm_snapshot) = match self .npm_resolver .as_inner() { InnerCliNpmResolverRef::Managed(managed) => { let snapshot = managed.serialized_valid_snapshot_for_system(&self.npm_system_info); if !snapshot.as_serialized().packages.is_empty() { let npm_vfs_builder = self.build_npm_vfs(&root_path, cli_options)?; ( Some(npm_vfs_builder), Some(NodeModules::Managed { node_modules_dir: self.npm_resolver.root_node_modules_path().map( |path| { root_dir_url .specifier_key( &ModuleSpecifier::from_directory_path(path).unwrap(), ) .into_owned() }, ), }), Some(snapshot), ) } else { (None, None, None) } } InnerCliNpmResolverRef::Byonm(resolver) => { let npm_vfs_builder = self.build_npm_vfs(&root_path, cli_options)?; ( Some(npm_vfs_builder), Some(NodeModules::Byonm { root_node_modules_dir: resolver.root_node_modules_path().map( |node_modules_dir| { root_dir_url .specifier_key( &ModuleSpecifier::from_directory_path(node_modules_dir) .unwrap(), ) .into_owned() }, ), }), None, ) } }; let mut vfs = if let Some(npm_vfs) = maybe_npm_vfs { npm_vfs } else { VfsBuilder::new(root_path.clone())? }; let mut remote_modules_store = RemoteModulesStoreBuilder::default(); for module in graph.modules() { if module.specifier().scheme() == "data" { continue; // don't store data urls as an entry as they're in the code } let (maybe_source, media_type) = match module { deno_graph::Module::Js(m) => { // todo(https://github.com/denoland/deno_media_type/pull/12): use is_emittable() let is_emittable = matches!( m.media_type, MediaType::TypeScript | MediaType::Mts | MediaType::Cts | MediaType::Jsx | MediaType::Tsx ); let source = if is_emittable { let source = self .emitter .emit_parsed_source(&m.specifier, m.media_type, &m.source) .await?; source.into_bytes() } else { m.source.as_bytes().to_vec() }; (Some(source), m.media_type) } deno_graph::Module::Json(m) => { (Some(m.source.as_bytes().to_vec()), m.media_type) } deno_graph::Module::Npm(_) | deno_graph::Module::Node(_) | deno_graph::Module::External(_) => (None, MediaType::Unknown), }; if module.specifier().scheme() == "file" { let file_path = deno_path_util::url_to_file_path(module.specifier())?; vfs .add_file_with_data( &file_path, match maybe_source { Some(source) => source, None => RealFs.read_file_sync(&file_path, None)?, }, ) .with_context(|| { format!("Failed adding '{}'", file_path.display()) })?; } else if let Some(source) = maybe_source { remote_modules_store.add(module.specifier(), media_type, source); } } remote_modules_store.add_redirects(&graph.redirects); let env_vars_from_env_file = match cli_options.env_file_name() { Some(env_filename) => { log::info!("{} Environment variables from the file \"{}\" were embedded in the generated executable file", crate::colors::yellow("Warning"), env_filename); get_file_env_vars(env_filename.to_string())? } None => Default::default(), }; let metadata = Metadata { argv: compile_flags.args.clone(), seed: cli_options.seed(), location: cli_options.location_flag().clone(), permissions: cli_options.permission_flags().clone(), v8_flags: cli_options.v8_flags().clone(), unsafely_ignore_certificate_errors: cli_options .unsafely_ignore_certificate_errors() .clone(), log_level: cli_options.log_level(), ca_stores: cli_options.ca_stores().clone(), ca_data, env_vars_from_env_file, entrypoint_key: root_dir_url.specifier_key(entrypoint).into_owned(), workspace_resolver: SerializedWorkspaceResolver { import_map: self.workspace_resolver.maybe_import_map().map(|i| { SerializedWorkspaceResolverImportMap { specifier: if i.base_url().scheme() == "file" { root_dir_url.specifier_key(i.base_url()).into_owned() } else { // just make a remote url local "deno.json".to_string() }, json: i.to_json(), } }), jsr_pkgs: self .workspace_resolver .jsr_packages() .map(|pkg| SerializedResolverWorkspaceJsrPackage { relative_base: root_dir_url.specifier_key(&pkg.base).into_owned(), name: pkg.name.clone(), version: pkg.version.clone(), exports: pkg.exports.clone(), }) .collect(), package_jsons: self .workspace_resolver .package_jsons() .map(|pkg_json| { ( root_dir_url .specifier_key(&pkg_json.specifier()) .into_owned(), serde_json::to_value(pkg_json).unwrap(), ) }) .collect(), pkg_json_resolution: self.workspace_resolver.pkg_json_dep_resolution(), }, node_modules, unstable_config: UnstableConfig { legacy_flag_enabled: false, bare_node_builtins: cli_options.unstable_bare_node_builtins(), detect_cjs: cli_options.unstable_detect_cjs(), sloppy_imports: cli_options.unstable_sloppy_imports(), features: cli_options.unstable_features(), }, }; write_binary_bytes( writer, original_bin, &metadata, npm_snapshot.map(|s| s.into_serialized()), &remote_modules_store, vfs, compile_flags, ) } fn build_npm_vfs( &self, root_path: &Path, cli_options: &CliOptions, ) -> Result { fn maybe_warn_different_system(system_info: &NpmSystemInfo) { if system_info != &NpmSystemInfo::default() { log::warn!("{} The node_modules directory may be incompatible with the target system.", crate::colors::yellow("Warning")); } } match self.npm_resolver.as_inner() { InnerCliNpmResolverRef::Managed(npm_resolver) => { if let Some(node_modules_path) = npm_resolver.root_node_modules_path() { maybe_warn_different_system(&self.npm_system_info); let mut builder = VfsBuilder::new(root_path.to_path_buf())?; builder.add_dir_recursive(node_modules_path)?; Ok(builder) } else { // DO NOT include the user's registry url as it may contain credentials, // but also don't make this dependent on the registry url let global_cache_root_path = npm_resolver.global_cache_root_folder(); let mut builder = VfsBuilder::new(global_cache_root_path)?; let mut packages = npm_resolver.all_system_packages(&self.npm_system_info); packages.sort_by(|a, b| a.id.cmp(&b.id)); // determinism for package in packages { let folder = npm_resolver.resolve_pkg_folder_from_pkg_id(&package.id)?; builder.add_dir_recursive(&folder)?; } // Flatten all the registries folders into a single ".deno_compile_node_modules/localhost" folder // that will be used by denort when loading the npm cache. This avoids us exposing // the user's private registry information and means we don't have to bother // serializing all the different registry config into the binary. builder.with_root_dir(|root_dir| { root_dir.name = ".deno_compile_node_modules".to_string(); let mut new_entries = Vec::with_capacity(root_dir.entries.len()); let mut localhost_entries = IndexMap::new(); for entry in std::mem::take(&mut root_dir.entries) { match entry { VfsEntry::Dir(dir) => { for entry in dir.entries { log::debug!( "Flattening {} into node_modules", entry.name() ); if let Some(existing) = localhost_entries.insert(entry.name().to_string(), entry) { panic!( "Unhandled scenario where a duplicate entry was found: {:?}", existing ); } } } VfsEntry::File(_) | VfsEntry::Symlink(_) => { new_entries.push(entry); } } } new_entries.push(VfsEntry::Dir(VirtualDirectory { name: "localhost".to_string(), entries: localhost_entries.into_iter().map(|(_, v)| v).collect(), })); // needs to be sorted by name new_entries.sort_by(|a, b| a.name().cmp(b.name())); root_dir.entries = new_entries; }); builder.set_new_root_path(root_path.to_path_buf())?; Ok(builder) } } InnerCliNpmResolverRef::Byonm(_) => { maybe_warn_different_system(&self.npm_system_info); let mut builder = VfsBuilder::new(root_path.to_path_buf())?; for pkg_json in cli_options.workspace().package_jsons() { builder.add_file_at_path(&pkg_json.path)?; } // traverse and add all the node_modules directories in the workspace let mut pending_dirs = VecDeque::new(); pending_dirs.push_back( cli_options.workspace().root_dir().to_file_path().unwrap(), ); while let Some(pending_dir) = pending_dirs.pop_front() { let mut entries = fs::read_dir(&pending_dir) .with_context(|| { format!("Failed reading: {}", pending_dir.display()) })? .collect::, _>>()?; entries.sort_by_cached_key(|entry| entry.file_name()); // determinism for entry in entries { let path = entry.path(); if !path.is_dir() { continue; } if path.ends_with("node_modules") { builder.add_dir_recursive(&path)?; } else { pending_dirs.push_back(path); } } } Ok(builder) } } } } /// This function returns the environment variables specified /// in the passed environment file. fn get_file_env_vars( filename: String, ) -> Result, dotenvy::Error> { let mut file_env_vars = IndexMap::new(); for item in dotenvy::from_filename_iter(filename)? { let Ok((key, val)) = item else { continue; // this failure will be warned about on load }; file_env_vars.insert(key, val); } Ok(file_env_vars) } /// This function sets the subsystem field in the PE header to 2 (GUI subsystem) /// For more information about the PE header: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format fn set_windows_binary_to_gui(bin: &mut [u8]) -> Result<(), AnyError> { // Get the PE header offset located in an i32 found at offset 60 // See: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#ms-dos-stub-image-only let start_pe = u32::from_le_bytes((bin[60..64]).try_into()?); // Get image type (PE32 or PE32+) indicates whether the binary is 32 or 64 bit // The used offset and size values can be found here: // https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#optional-header-image-only let start_32 = start_pe as usize + 28; let magic_32 = u16::from_le_bytes(bin[(start_32)..(start_32 + 2)].try_into()?); let start_64 = start_pe as usize + 24; let magic_64 = u16::from_le_bytes(bin[(start_64)..(start_64 + 2)].try_into()?); // Take the standard fields size for the current architecture (32 or 64 bit) // This is the ofset for the Windows-Specific fields let standard_fields_size = if magic_32 == 0x10b { 28 } else if magic_64 == 0x20b { 24 } else { bail!("Could not find a matching magic field in the PE header") }; // Set the subsystem field (offset 68) to 2 (GUI subsystem) // For all possible options, see: https://learn.microsoft.com/en-us/windows/win32/debug/pe-format#optional-header-windows-specific-fields-image-only let subsystem_offset = 68; let subsystem_start = start_pe as usize + standard_fields_size + subsystem_offset; let subsystem: u16 = 2; bin[(subsystem_start)..(subsystem_start + 2)] .copy_from_slice(&subsystem.to_le_bytes()); Ok(()) }