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// Copyright 2016-2022 the Tectonic Project
// Licensed under the MIT License.
#![deny(missing_docs)]
//! Core APIs for bridging the C and Rust portions of Tectonic’s processing
//! backends.
//!
//! This crate is used by the Tectonic “engines”, which are predominantly C/C++
//! code derived from the original TeX codebase. It provides a framework so that
//! the C/C++ code can invoke the support services provided by Tectonic, such as
//! its pluggable I/O backends. The interfaces exposed to the C/C++ layers are
//! created by [cbindgen].
//!
//! [cbindgen]: https://github.com/eqrion/cbindgen
//!
//! If you change the interfaces here, rerun cbindgen as described in the README!
//!
//! In order to provide access to a C/C++ engine in Rust, you should create some
//! kind of interface that expects to be given a reference to a
//! [`CoreBridgeLauncher`] struct. You should use that struct's
//! `with_global_lock` method to obtain a [`CoreBridgeState`] reference, and
//! then pass that reference across the FFI layer. On the other side of the FFI
//! divide, your code *must* call the functions `ttbc_global_engine_enter()` and
//! `ttbc_global_engine_exit()` according to the pattern described in
//! `tectonic_bridge_core.h`. If an abort is detected, the callback function
//! must return `Err(EngineAbortedError::new_abort_indicator().into())`.
//! Unfortunately, this is the cleanest and most reliable API that we can
//! provide because our abort handling uses `setjmp`/`longjmp` and those can't
//! cross FFI boundaries.
//!
//! In order to use a C/C++ engine, you need to provide something that
//! implements the [`DriverHooks`] trait. The [`MinimalDriver`] struct provides
//! a minimal implementation that only requires you to provide an [`IoProvider`]
//! implementation.
use flate2::{read::GzDecoder, Compression, GzBuilder};
use md5::{Digest, Md5};
use std::{
convert::TryInto,
ffi::CStr,
fmt::{Display, Error as FmtError, Formatter},
io::{self, Read, SeekFrom, Write},
path::PathBuf,
ptr,
result::Result as StdResult,
slice,
sync::Mutex,
};
use tectonic_errors::prelude::*;
use tectonic_io_base::{
digest::DigestData, normalize_tex_path, InputFeatures, InputHandle, IoProvider, OpenResult,
OutputHandle,
};
use tectonic_status_base::{tt_error, tt_warning, MessageKind, StatusBackend};
/// Possible failures for “system request” calls to the driver.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum SystemRequestError {
/// The driver does not implement this system request.
NotImplemented,
/// The driver implements this system request but is not allowing it
/// to be used in this circumstance.
NotAllowed,
/// The driver tried to execute this system request but it failed in some
/// fashion. There's no facility for providing more detailed information
/// because the calling C/C++ code can't do anything useful with the
/// details.
Failed,
}
impl Display for SystemRequestError {
fn fmt(&self, f: &mut Formatter) -> StdResult<(), FmtError> {
write!(
f,
"{}",
match self {
SystemRequestError::NotImplemented => "not implemented by this driver",
SystemRequestError::NotAllowed => "not allowed by this driver",
SystemRequestError::Failed => "execution of the request failed",
}
)
}
}
/// The DriverHooks trait allows engines to interact with the higher-level code
/// that is driving the TeX processing.
///
/// Drivers mainly manage interactions between the engines and the outside
/// world. The primary way they do this is by exposing an [`IoProvider`]
/// implementation.
///
/// Drivers can also implement handlers for additional events that help it track
/// the input and output access patterns of the engines. The CLI program needs
/// these to intelligently decide when to rerun the TeX engine, to choose which
/// files to actually save to disk, and to emit Makefile rules describing the
/// dependency of the outputs on the inputs. The relevant trait methods have
/// default implementations that do nothing.
pub trait DriverHooks {
/// Get the main I/O implementations of this driver.
fn io(&mut self) -> &mut dyn IoProvider;
/// This function is called when an output file is closed. The "digest"
/// argument specifies the cryptographic digest of the data that were
/// written. Note that this function takes ownership of the name and
/// digest.
fn event_output_closed(
&mut self,
_name: String,
_digest: DigestData,
_status: &mut dyn StatusBackend,
) {
}
/// This function is called when an input file is closed. The "digest"
/// argument specifies the cryptographic digest of the data that were
/// read, if available. This digest is not always available, if the engine
/// used seeks while reading the file. Note that this function takes
/// ownership of the name and digest.
fn event_input_closed(
&mut self,
_name: String,
_digest: Option<DigestData>,
_status: &mut dyn StatusBackend,
) {
}
/// The engine is requesting a “shell escape” evaluation.
///
/// If the driver wishes to implement this request, it should run the
/// specified command using the OS’s default shell. Relevant files should be
/// available in the command's working directory, and if the command creates
/// any files, they should be incorporated into the I/O environment. The
/// shell-escape environment should persist across multiple invocations of
/// this system request, because some packages run a series of commands that
/// assume such persistence. Also note that the command text has to be
/// evaluated through a shell, not just with `exec()`, since shell features
/// such as redirections might be used. This is therefore a wildly insecure
/// feature.
///
/// This function can only return a limited range of error values because
/// the C/C++ engines can't do anything useful with them. Detailed error
/// information should be logged or stored inside the hook function.
fn sysrq_shell_escape(
&mut self,
_command: &str,
_status: &mut dyn StatusBackend,
) -> StdResult<(), SystemRequestError> {
Err(SystemRequestError::NotImplemented)
}
}
/// This type provides a minimal [`DriverHooks`] implementation.
#[derive(Clone, Debug, Default)]
pub struct MinimalDriver<T: IoProvider>(T);
impl<T: IoProvider> MinimalDriver<T> {
/// Create a new minimal driver.
pub fn new(io: T) -> Self {
MinimalDriver(io)
}
}
impl<T: IoProvider> DriverHooks for MinimalDriver<T> {
fn io(&mut self) -> &mut dyn IoProvider {
&mut self.0
}
}
// Function defined in the C support code:
extern "C" {
fn _ttbc_get_error_message() -> *const libc::c_char;
}
lazy_static::lazy_static! {
static ref ENGINE_LOCK: Mutex<u8> = Mutex::new(0u8);
}
/// An error type indicating the the FFI code aborted.
///
/// FFI bridge callbacks should return this type, which will then be filled in
/// with error text extracted from the global FFI bridge framework.
#[derive(Debug)]
pub struct EngineAbortedError {
message: String,
}
impl EngineAbortedError {
/// Create an error indicating that the FFI engine aborted.
///
/// Upon exit, the global bridge FFI framework will report an
/// error of this same type, but filled in with error text extracted
/// from the global FFI bridge framework.
pub fn new_abort_indicator() -> Self {
EngineAbortedError {
message: "[failed to extract detailed error message]".to_owned(),
}
}
unsafe fn new_with_details() -> Self {
let ptr = _ttbc_get_error_message();
let message = CStr::from_ptr(ptr).to_string_lossy().into_owned();
EngineAbortedError { message }
}
}
impl Display for EngineAbortedError {
fn fmt(&self, f: &mut Formatter) -> StdResult<(), FmtError> {
write!(f, "{}", self.message)
}
}
impl std::error::Error for EngineAbortedError {}
/// A mechanism for launching bridged FFI code.
pub struct CoreBridgeLauncher<'a> {
hooks: &'a mut dyn DriverHooks,
status: &'a mut dyn StatusBackend,
security: SecuritySettings,
filesystem_emulation_settings: FsEmulationSettings,
}
impl<'a> CoreBridgeLauncher<'a> {
/// Set up a new context for launching bridged FFI code.
///
/// This function uses the default security stance, which disallows all
/// known-insecure engine features. Use [`Self::new_with_security`] to
/// provide your own security settings that can attempt to allow the use of
/// such features.
pub fn new(hooks: &'a mut dyn DriverHooks, status: &'a mut dyn StatusBackend) -> Self {
Self::new_with_security(hooks, status, SecuritySettings::default())
}
/// Set up a new context for launching bridged FFI code.
pub fn new_with_security(
hooks: &'a mut dyn DriverHooks,
status: &'a mut dyn StatusBackend,
security: SecuritySettings,
) -> Self {
CoreBridgeLauncher {
hooks,
status,
security,
filesystem_emulation_settings: FsEmulationSettings::default(),
}
}
/// While absolute paths are useful (for SyncTeX and external tools that
/// resolve paths to TeX sources), we can disable them for reproducibility.
pub fn with_expose_absolute_paths(&mut self, expose_absolute_paths: bool) -> &mut Self {
self.filesystem_emulation_settings.expose_absolute_paths = expose_absolute_paths;
self
}
/// Ditto for file modification timestamps. In deterministic mode, we return
/// the configured build time (i.e. `SOURCE_DATE_EPOCH`) instead of the
/// modification timestamp reported by the IO subsystem.
pub fn with_mtime_override(&mut self, mtime_override: Option<i64>) -> &mut Self {
self.filesystem_emulation_settings.mtime_override = mtime_override;
self
}
/// Invoke a function to launch a bridged FFI engine with a global mutex
/// held.
///
/// This function *must* be used when invoking C code that makes use of the
/// global core bridge state functions. Unfortunately, because our error
/// reporting is based on setjmp/longjmp and it is Undefined Behavior to
/// setjmp/longjmp across FFI boundaries, we cannot provide a more foolproof
/// API.
///
/// The invoked code *must* call the functions `ttbc_global_engine_enter`
/// and `ttbc_global_engine_exit` according to the pattern described in
/// `tectonic_bridge_core.h`. If an abort is detected, the callback function
/// should return `Err(EngineAbortedError::new_abort_indicator())`.
pub fn with_global_lock<F, T>(&mut self, callback: F) -> Result<T>
where
F: FnOnce(&mut CoreBridgeState<'_>) -> Result<T>,
{
let _guard = ENGINE_LOCK.lock().unwrap();
let mut state = CoreBridgeState::new(
self.security.clone(),
self.hooks,
self.status,
self.filesystem_emulation_settings.clone(),
);
let result = callback(&mut state);
if let Err(ref e) = result {
if e.downcast_ref::<EngineAbortedError>().is_some() {
return Err(unsafe { EngineAbortedError::new_with_details() }.into());
}
}
result
}
}
/// The CoreBridgeState structure is a handle to Rust state that can be used by
/// C/C++ engine code to perform basic I/O functions.
///
/// Code that invokes a Tectonic C/C++ engine should pass a pointer to one of
/// these state structures into the C/C++ layer. It is essential that lifetimes
/// be properly managed across the Rust/C boundary.
pub struct CoreBridgeState<'a> {
/// The security settings for this invocation
security: SecuritySettings,
/// The filesystem emulation settings for this invocation.
fs_emulation_settings: FsEmulationSettings,
/// The driver hooks associated with this engine invocation.
hooks: &'a mut dyn DriverHooks,
/// The status-reporting backend associated with this engine invocation.
status: &'a mut dyn StatusBackend,
#[allow(clippy::vec_box)]
input_handles: Vec<Box<InputHandle>>,
#[allow(clippy::vec_box)]
output_handles: Vec<Box<OutputHandle>>,
/// A semi-hack to allow us to feed input file path information to SyncTeX.
/// This field is updated every time a new input file is opened. The XeTeX
/// engine queries it when opening new source input files to get the
/// absolute filesystem path info that SyncTeX wants. This field might be
/// None because we're still reading the primary input, or because the most
/// recent input didn't have a filesystem path (it came from a bundle or
/// memory or something else).
latest_input_path: Option<PathBuf>,
}
impl<'a> CoreBridgeState<'a> {
fn new(
security: SecuritySettings,
hooks: &'a mut dyn DriverHooks,
status: &'a mut dyn StatusBackend,
fs_emulation_settings: FsEmulationSettings,
) -> CoreBridgeState<'a> {
CoreBridgeState {
security,
hooks,
status,
output_handles: Vec::new(),
input_handles: Vec::new(),
latest_input_path: None,
fs_emulation_settings,
}
}
fn input_open_name_format(
&mut self,
name: &str,
format: FileFormat,
) -> OpenResult<(InputHandle, Option<PathBuf>)> {
let io = self.hooks.io();
if let FileFormat::Format = format {
match io.input_open_format(name, self.status) {
OpenResult::NotAvailable => {}
OpenResult::Err(e) => return OpenResult::Err(e),
OpenResult::Ok(h) => return OpenResult::Ok((h, None)),
}
} else {
match io.input_open_name_with_abspath(name, self.status) {
OpenResult::NotAvailable => {}
r => return r,
}
}
// It wasn't available under the immediately-given name. Try adding
// extensions. Note that we always add a new extension here, even if the
// filename already has one. E.g., lipsum in TeXLive 2020 asks for
// `lipsum.ltd.tex` under the name `lipsum.ltd`.
for e in format.extensions() {
let ext = format!("{name}.{e}");
if let FileFormat::Format = format {
match io.input_open_format(&ext, self.status) {
OpenResult::NotAvailable => {}
OpenResult::Err(e) => return OpenResult::Err(e),
OpenResult::Ok(h) => return OpenResult::Ok((h, None)),
}
} else {
match io.input_open_name_with_abspath(&ext, self.status) {
OpenResult::NotAvailable => {}
r => return r,
}
}
}
OpenResult::NotAvailable
}
fn input_open_name_format_gz(
&mut self,
name: &str,
format: FileFormat,
is_gz: bool,
) -> OpenResult<(InputHandle, Option<PathBuf>)> {
let base = self.input_open_name_format(name, format);
if !is_gz {
return base;
}
match base {
OpenResult::Ok((ih, path)) => {
let origin = ih.origin();
let dr = GzDecoder::new(ih.into_inner());
OpenResult::Ok((InputHandle::new(name, dr, origin), path))
}
_ => base,
}
}
fn get_file_md5(&mut self, name: &str, dest: &mut [u8]) -> bool {
let name = normalize_tex_path(name);
let mut hash = Md5::default();
// We could try to be fancy and look up the file in our cache to see
// if we've already computed is SHA256 ... and then lie and use a
// truncated SHA256 digest as the MD5 ... but it seems like a better
// idea to just go and read the file.
let mut ih = match self.input_open_name_format(&name, FileFormat::Tex) {
OpenResult::Ok((ih, _path)) => ih,
OpenResult::NotAvailable => {
// We could issue a warning here, but the standard LaTeX
// "rerun check" implementations trigger it very often, which
// gets annoying. So we'll let this particular failure mode be
// silent.
return true;
}
OpenResult::Err(e) => {
tt_error!(self.status, "error trying to open file \"{}\" for MD5 calculation",
name; e);
return true;
}
};
// No canned way to stream the whole file into the digest, it seems.
const BUF_SIZE: usize = 1024;
let mut buf = [0u8; BUF_SIZE];
let mut error_occurred = false;
loop {
let nread = match ih.read(&mut buf) {
Ok(0) => {
break;
}
Ok(n) => n,
Err(e) => {
tt_error!(self.status, "error reading file \"{}\" for MD5 calculation",
ih.name(); e.into());
error_occurred = true;
break;
}
};
hash.update(&buf[..nread]);
}
// Clean up.
let (name, digest_opt) = ih.into_name_digest();
self.hooks.event_input_closed(name, digest_opt, self.status);
if !error_occurred {
let result = hash.finalize();
dest.copy_from_slice(result.as_slice());
}
error_occurred
}
fn output_open(&mut self, name: &str, is_gz: bool) -> *mut OutputHandle {
let io = self.hooks.io();
let name = normalize_tex_path(name);
let mut oh = match io.output_open_name(&name) {
OpenResult::Ok(oh) => oh,
OpenResult::NotAvailable => return ptr::null_mut(),
OpenResult::Err(e) => {
tt_warning!(self.status, "open of output {} failed", name; e);
return ptr::null_mut();
}
};
if is_gz {
let name = oh.name().to_owned();
oh = OutputHandle::new(
name,
GzBuilder::new().write(oh.into_inner(), Compression::default()),
);
}
self.output_handles.push(Box::new(oh));
&mut **self.output_handles.last_mut().unwrap()
}
fn output_open_stdout(&mut self) -> *mut OutputHandle {
let io = self.hooks.io();
let oh = match io.output_open_stdout() {
OpenResult::Ok(oh) => oh,
OpenResult::NotAvailable => return ptr::null_mut(),
OpenResult::Err(e) => {
tt_warning!(self.status, "open of stdout failed"; e);
return ptr::null_mut();
}
};
self.output_handles.push(Box::new(oh));
&mut **self.output_handles.last_mut().unwrap()
}
fn output_write(&mut self, handle: *mut OutputHandle, buf: &[u8]) -> bool {
let rhandle: &mut OutputHandle = unsafe { &mut *handle };
let result = rhandle.write_all(buf);
match result {
Ok(_) => false,
Err(e) => {
tt_warning!(self.status, "write failed"; e.into());
true
}
}
}
fn output_flush(&mut self, handle: *mut OutputHandle) -> bool {
let rhandle: &mut OutputHandle = unsafe { &mut *handle };
let result = rhandle.flush();
match result {
Ok(_) => false,
Err(e) => {
tt_warning!(self.status, "flush failed"; e.into());
true
}
}
}
fn output_close(&mut self, handle: *mut OutputHandle) -> bool {
let len = self.output_handles.len();
let mut rv = false;
for i in 0..len {
let p: *const OutputHandle = &*self.output_handles[i];
if p == handle {
let mut oh = self.output_handles.swap_remove(i);
if let Err(e) = oh.flush() {
tt_warning!(self.status, "error when closing output {}", oh.name(); e.into());
rv = true;
}
let (name, digest) = oh.into_name_digest();
self.hooks.event_output_closed(name, digest, self.status);
break;
}
}
rv
}
fn input_open(&mut self, name: &str, format: FileFormat, is_gz: bool) -> *mut InputHandle {
let name = normalize_tex_path(name);
let (ih, path) = match self.input_open_name_format_gz(&name, format, is_gz) {
OpenResult::Ok(tup) => tup,
OpenResult::NotAvailable => {
return ptr::null_mut();
}
OpenResult::Err(e) => {
tt_warning!(self.status, "open of input {} failed", name; e);
return ptr::null_mut();
}
};
self.input_handles.push(Box::new(ih));
self.latest_input_path = path;
&mut **self.input_handles.last_mut().unwrap()
}
fn input_open_primary(&mut self) -> *mut InputHandle {
let io = self.hooks.io();
let (ih, path) = match io.input_open_primary_with_abspath(self.status) {
OpenResult::Ok(tup) => tup,
OpenResult::NotAvailable => {
tt_error!(self.status, "primary input not available (?!)");
return ptr::null_mut();
}
OpenResult::Err(e) => {
tt_error!(self.status, "open of primary input failed"; e);
return ptr::null_mut();
}
};
self.input_handles.push(Box::new(ih));
self.latest_input_path = path;
&mut **self.input_handles.last_mut().unwrap()
}
fn input_get_size(&mut self, handle: *mut InputHandle) -> usize {
let rhandle: &mut InputHandle = unsafe { &mut *handle };
match rhandle.get_size() {
Ok(s) => s,
Err(e) => {
tt_warning!(self.status, "failed to get the size of an input"; e);
0
}
}
}
fn input_get_mtime(&mut self, handle: *mut InputHandle) -> i64 {
if let Some(mtime) = self.fs_emulation_settings.mtime_override {
return mtime;
}
let rhandle: &mut InputHandle = unsafe { &mut *handle };
let maybe_time = match rhandle.get_unix_mtime() {
Ok(t) => t,
Err(e) => {
tt_warning!(self.status, "failed to get the modification time of an input"; e);
Some(0)
}
};
if let Some(t) = maybe_time {
t
} else {
1 // Intentionally make this distinguishable from the error value 0
}
}
fn input_seek(&mut self, handle: *mut InputHandle, pos: SeekFrom) -> Result<u64> {
let rhandle: &mut InputHandle = unsafe { &mut *handle };
rhandle.try_seek(pos)
}
fn input_read(&mut self, handle: *mut InputHandle, buf: &mut [u8]) -> Result<()> {
let rhandle: &mut InputHandle = unsafe { &mut *handle };
rhandle.read_exact(buf).map_err(Error::from)
}
fn input_getc(&mut self, handle: *mut InputHandle) -> Result<u8> {
let rhandle: &mut InputHandle = unsafe { &mut *handle };
rhandle.getc()
}
fn input_ungetc(&mut self, handle: *mut InputHandle, byte: u8) -> Result<()> {
let rhandle: &mut InputHandle = unsafe { &mut *handle };
rhandle.ungetc(byte)
}
fn input_close(&mut self, handle: *mut InputHandle) -> bool {
let len = self.input_handles.len();
for i in 0..len {
let p: *const InputHandle = &*self.input_handles[i];
if p == handle {
let mut ih = self.input_handles.swap_remove(i);
let mut rv = false;
if let Err(e) = ih.scan_remainder() {
tt_warning!(self.status, "error closing out input {}", ih.name(); e);
rv = true;
}
let (name, digest_opt) = ih.into_name_digest();
self.hooks.event_input_closed(name, digest_opt, self.status);
return rv;
}
}
// TODO: Handle the error better. This indicates a bug in the engine.
tt_error!(
self.status,
"serious internal bug: unexpected handle in input close: {:?}",
handle
);
true
}
fn shell_escape(&mut self, command: &str) -> bool {
if self.security.allow_shell_escape() {
match self.hooks.sysrq_shell_escape(command, self.status) {
Ok(_) => false,
Err(e) => {
tt_error!(
self.status,
"failed to execute the shell-escape command \"{}\": {}",
command,
e
);
true
}
}
} else {
tt_error!(
self.status,
"forbidden to execute shell-escape command \"{}\"",
command
);
true
}
}
}
/// A type for storing settings about potentially insecure engine features.
///
/// This type encapsulates configuration about which potentially insecure engine
/// features are enabled. Methods that configure or instantiate engines require
/// values of this type, and values of this type can only be created through
/// centralized methods that respect standard environment variables, ensuring
/// that there is some level of uniform control over the activation of any
/// known-insecure features.
///
/// The purpose of this framework is to manage the use of engine features that
/// are known to create security risks with *untrusted* input, but that trusted
/// users may wish to use due to the extra functionalities they bring. (This is
/// why these are settings and not simply security flaws!) The primary example
/// of this is the TeX engine’s shell-escape feature.
///
/// Of course, this framework is only as good as our understanding of Tectonic’s
/// security profile. Future versions might disable or restrict different pieces
/// of functionality as new risks are discovered.
#[derive(Clone, Debug)]
pub struct SecuritySettings {
/// While we might eventually gain finer-grained enable/disable settings,
/// there should always be a hard "disable everything known to be risky"
/// option that supersedes everything else.
disable_insecures: bool,
}
/// Different high-level security stances that can be adopted when creating
/// [`SecuritySettings`].
#[derive(Clone, Debug, Default)]
pub enum SecurityStance {
/// Ensure that all known-insecure features are disabled.
///
/// Use this stance if you are processing untrusted input.
#[default]
DisableInsecures,
/// Request to allow the use of known-insecure features.
///
/// Use this stance if you are processing trusted input *and* there is some
/// user-level request to use such features. The request to allow insecure
/// features might be overridden if the environment variable
/// `TECTONIC_UNTRUSTED_MODE` is set.
MaybeAllowInsecures,
}
impl SecuritySettings {
/// Create a new security configuration.
///
/// The *stance* argument specifies the high-level security stance. If your
/// program will be run by a trusted user, they should be able to control
/// the setting through a command-line argument or something comparable.
/// Even if there is a request to enable known-insecure features, however,
/// such a request might be overridden by other mechanisms. In particular,
/// if the environment variable `TECTONIC_UNTRUSTED_MODE` is set to any
/// value, insecure features will always be disabled regardless of the
/// user-level setting. Other mechanisms for disable known-insecure features
/// may be added in the future.
pub fn new(stance: SecurityStance) -> Self {
let disable_insecures = if std::env::var_os("TECTONIC_UNTRUSTED_MODE").is_some() {
true
} else {
match stance {
SecurityStance::DisableInsecures => true,
SecurityStance::MaybeAllowInsecures => false,
}
};
SecuritySettings { disable_insecures }
}
/// Query whether the shell-escape TeX engine feature is allowed to be used.
pub fn allow_shell_escape(&self) -> bool {
!self.disable_insecures
}
/// Query whether we're allowed to specify extra paths to read files from.
pub fn allow_extra_search_paths(&self) -> bool {
!self.disable_insecures
}
}
impl Default for SecuritySettings {
fn default() -> Self {
SecuritySettings::new(SecurityStance::default())
}
}
/// A type that stores configuration knobs related to filesystem emulation.
/// These options are not security-critical, but are relevant for
/// reproducible document builds. We default to an "accurate" view of the
/// underlying IO subsystem and have options that stub the respective IO
/// functions with fake / stable values.
#[derive(Clone, Debug)]
struct FsEmulationSettings {
/// While absolute paths are useful (for SyncTeX and external tools that
/// resolve paths to TeX sources), we can disable them for reproducibility.
expose_absolute_paths: bool,
/// Ditto for file modification timestamps. In deterministic mode, we return
/// the configured build time (i.e. `SOURCE_DATE_EPOCH`) instead of the
/// modification timestamp reported by the IO subsystem.
mtime_override: Option<i64>,
}
impl Default for FsEmulationSettings {
fn default() -> Self {
Self {
expose_absolute_paths: true,
mtime_override: None,
}
}
}
// The entry points.
/// Issue a warning.
///
/// # Safety
///
/// This function is unsafe because it accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_issue_warning(es: &mut CoreBridgeState, text: *const libc::c_char) {
let rtext = CStr::from_ptr(text);
tt_warning!(es.status, "{}", rtext.to_string_lossy());
}
/// Issue an error.
///
/// # Safety
///
/// This function is unsafe because it accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_issue_error(es: &mut CoreBridgeState, text: *const libc::c_char) {
let rtext = CStr::from_ptr(text);
tt_error!(es.status, "{}", rtext.to_string_lossy());
}
/// Calculate the MD5 digest of a Tectonic file.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw pointers from C.
#[no_mangle]
pub unsafe extern "C" fn ttbc_get_file_md5(
es: &mut CoreBridgeState,
path: *const libc::c_char,
digest: *mut u8,
) -> libc::c_int {
let rpath = CStr::from_ptr(path).to_string_lossy();
let rdest = slice::from_raw_parts_mut(digest, 16);
libc::c_int::from(es.get_file_md5(rpath.as_ref(), rdest))
}
/// Calculate the MD5 digest of a block of binary data.
///
/// This actually doesn't rely on the state and isn't really I/O, but we also
/// have a get-file-MD5 routine so it's convenient to have this here.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw pointers from C.
#[no_mangle]
pub unsafe extern "C" fn ttbc_get_data_md5(
data: *const u8,
len: libc::size_t,
digest: *mut u8,
) -> libc::c_int {
let rdata = slice::from_raw_parts(data, len);
let rdest = slice::from_raw_parts_mut(digest, 16);
let mut hash = Md5::default();
hash.update(rdata);
let result = hash.finalize();
rdest.copy_from_slice(result.as_slice());
0
}
/// Open a Tectonic file for output.
///
/// # Safety
///
/// This function is unsafe because it accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_output_open(
es: &mut CoreBridgeState,
name: *const libc::c_char,
is_gz: libc::c_int,
) -> *mut OutputHandle {
let rname = CStr::from_ptr(name).to_string_lossy();
let ris_gz = is_gz != 0;
es.output_open(&rname, ris_gz)
}
/// Open the general user output stream as a Tectonic output file.
#[no_mangle]
pub extern "C" fn ttbc_output_open_stdout(es: &mut CoreBridgeState) -> *mut OutputHandle {
es.output_open_stdout()
}
/// Write a single character to a Tectonic output file.
#[no_mangle]
pub extern "C" fn ttbc_output_putc(
es: &mut CoreBridgeState,
handle: *mut OutputHandle,
c: libc::c_int,
) -> libc::c_int {
let rc = c as u8;
if es.output_write(handle, &[rc]) {
libc::EOF
} else {
c
}
}
/// Write data to a Tectonic output file.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw C pointers.
#[no_mangle]
pub unsafe extern "C" fn ttbc_output_write(
es: &mut CoreBridgeState,
handle: *mut OutputHandle,
data: *const u8,
len: libc::size_t,
) -> libc::size_t {
let rdata = slice::from_raw_parts(data, len);
// NOTE: we use f.write_all() so partial writes are not gonna be a thing.
if es.output_write(handle, rdata) {
0
} else {
len
}
}
/// Flush pending writes to a Tectonic output file.
#[no_mangle]
pub extern "C" fn ttbc_output_flush(
es: &mut CoreBridgeState,
handle: *mut OutputHandle,
) -> libc::c_int {
libc::c_int::from(es.output_flush(handle))
}
/// Close a Tectonic output file.
#[no_mangle]
pub extern "C" fn ttbc_output_close(
es: &mut CoreBridgeState,
handle: *mut OutputHandle,
) -> libc::c_int {
if handle.is_null() {
return 0; // This is/was the behavior of close_file() in C.
}
libc::c_int::from(es.output_close(handle))
}
/// Open a Tectonic file for input.
///
/// # Safety
///
/// This function is unsafe because it accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_input_open(
es: &mut CoreBridgeState,
name: *const libc::c_char,
format: FileFormat,
is_gz: libc::c_int,
) -> *mut InputHandle {
let rname = CStr::from_ptr(name).to_string_lossy();
let ris_gz = is_gz != 0;
es.input_open(&rname, format, ris_gz)
}
/// Open the "primary input" file.
#[no_mangle]
pub extern "C" fn ttbc_input_open_primary(es: &mut CoreBridgeState) -> *mut InputHandle {
es.input_open_primary()
}
/// Get the filesystem path of the most-recently-opened input file.
///
/// This function is needed by SyncTeX, because its output file should contain
/// absolute filesystem paths to the input source files. In principle this
/// functionality could be implemented in a few different ways, but the approach
/// used here is the most backward-compatible. This function will fill in the
/// caller's buffer with the filesystem path associated with the most
/// recently-opened input file, including a terminating NUL, if possible.
///
/// It returns 0 if no such path is known, -1 if the path cannot be expressed
/// UTF-8, -2 if the destination buffer is not big enough, or the number of
/// bytes written into the buffer (including a terminating NUL) otherwise.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw C pointers.
#[no_mangle]
pub unsafe extern "C" fn ttbc_get_last_input_abspath(
es: &mut CoreBridgeState,
buffer: *mut u8,
len: libc::size_t,
) -> libc::ssize_t {
if !es.fs_emulation_settings.expose_absolute_paths {
return 0;
}
match es.latest_input_path {
None => 0,
Some(ref p) => {
// In principle we could try to handle the full fun of
// cross-platform PathBuf/Unicode conversions, but synctex and
// friends will be treating our data as a traditional C string in
// the end. So play it safe and stick to UTF-8.
let p = match p.to_str() {
Some(s) => s.as_bytes(),
None => return -1,
};
let n = p.len();
if n + 1 > len {
return -2;
}
std::ptr::copy(p.as_ptr(), buffer, n);
*buffer.offset(n.try_into().unwrap()) = b'\0';
(n + 1).try_into().unwrap()
}
}
}
/// Get the size of a Tectonic input file.
#[no_mangle]
pub extern "C" fn ttbc_input_get_size(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
) -> libc::size_t {
es.input_get_size(handle)
}
/// Get the modification time of a Tectonic input file.
#[no_mangle]
pub extern "C" fn ttbc_input_get_mtime(es: &mut CoreBridgeState, handle: *mut InputHandle) -> i64 {
es.input_get_mtime(handle)
}
/// Seek in a Tectonic input stream.
///
/// # Safety
///
/// This function is unsafe because it dereferences raw pointers from C.
#[no_mangle]
pub unsafe extern "C" fn ttbc_input_seek(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
offset: libc::ssize_t,
whence: libc::c_int,
internal_error: *mut libc::c_int,
) -> libc::size_t {
let rwhence = match whence {
libc::SEEK_SET => SeekFrom::Start(offset as u64),
libc::SEEK_CUR => SeekFrom::Current(offset as i64),
libc::SEEK_END => SeekFrom::End(offset as i64),
_ => {
tt_error!(
es.status,
"serious internal bug: unexpected \"whence\" parameter to fseek() wrapper: {}",
whence
);
*internal_error = 1;
return 0;
}
};
match es.input_seek(handle, rwhence) {
Ok(pos) => pos as libc::size_t,
Err(e) => {
// TODO: Handle the error better. Report the error properly to the caller?
tt_error!(es.status, "input seek failed"; e);
0
}
}
}
/// Get a single character from a Tectonic input file.
#[no_mangle]
pub extern "C" fn ttbc_input_getc(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
) -> libc::c_int {
// If we couldn't fill the whole (1-byte) buffer, that's boring old EOF.
// No need to complain. Fun match statement here.
match es.input_getc(handle) {
Ok(b) => libc::c_int::from(b),
Err(e) => {
if let Some(ioe) = e.downcast_ref::<io::Error>() {
if ioe.kind() == io::ErrorKind::UnexpectedEof {
return libc::EOF;
}
}
tt_warning!(es.status, "getc failed"; e);
-1
}
}
}
/// Put back a character that was obtained from a `getc` call.
#[no_mangle]
pub extern "C" fn ttbc_input_ungetc(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
ch: libc::c_int,
) -> libc::c_int {
match es.input_ungetc(handle, ch as u8) {
Ok(_) => 0,
Err(e) => {
tt_warning!(es.status, "ungetc() failed"; e);
-1
}
}
}
/// Read data from a Tectonic input handle
///
/// # Safety
///
/// This function is unsafe because it dereferences raw C pointers.
#[no_mangle]
pub unsafe extern "C" fn ttbc_input_read(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
data: *mut u8,
len: libc::size_t,
) -> libc::ssize_t {
let rdata = slice::from_raw_parts_mut(data, len);
match es.input_read(handle, rdata) {
Ok(_) => len as isize,
Err(e) => {
tt_warning!(es.status, "{}-byte read failed", len; e);
-1
}
}
}
/// Close a Tectonic input file.
#[no_mangle]
pub extern "C" fn ttbc_input_close(
es: &mut CoreBridgeState,
handle: *mut InputHandle,
) -> libc::c_int {
if handle.is_null() {
return 0; // This is/was the behavior of close_file() in C.
}
libc::c_int::from(es.input_close(handle))
}
/// A buffer for diagnostic messages. Rust code does not need to use this type.
///
/// This type has to be public so that it can be exposed in the C/C++ headers,
/// but it doesn't provide any useful functionality on the Rust side.
#[derive(Clone, Debug)]
pub struct Diagnostic {
message: String,
kind: MessageKind,
}
/// Create a new diagnostic that will be reported as a warning.
#[no_mangle]
pub extern "C" fn ttbc_diag_begin_warning() -> *mut Diagnostic {
let warning = Box::new(Diagnostic {
message: String::new(),
kind: MessageKind::Warning,
});
Box::into_raw(warning)
}
/// Create a new diagnostic that will be reported as an error.
#[no_mangle]
pub extern "C" fn ttbc_diag_begin_error() -> *mut Diagnostic {
let warning = Box::new(Diagnostic {
message: String::new(),
kind: MessageKind::Error,
});
Box::into_raw(warning)
}
/// Append text to a diagnostic.
///
/// # Safety
///
/// This function is unsafe because it accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_diag_append(diag: &mut Diagnostic, text: *const libc::c_char) {
let rtext = CStr::from_ptr(text);
diag.message.push_str(&rtext.to_string_lossy());
}
/// "Finish" a diagnostic: report it to the driver and free the diagnostic object.
///
/// # Safety
///
/// This function is unsafe because it dereferences a raw Diagnostic pointer
#[no_mangle]
pub unsafe extern "C" fn ttbc_diag_finish(es: &mut CoreBridgeState, diag: *mut Diagnostic) {
// By creating the box, we will free the diagnostic when this function exits.
let rdiag = Box::from_raw(diag);
es.status
.report(rdiag.kind, format_args!("{}", rdiag.message), None);
}
/// Run a shell command
///
/// # Safety
///
/// This function is unsafe because it dereferences raw pointers from C and accepts a raw C string.
#[no_mangle]
pub unsafe extern "C" fn ttbc_shell_escape(
es: &mut CoreBridgeState,
cmd: *const u16,
len: libc::size_t,
) -> libc::c_int {
let rcmd = slice::from_raw_parts(cmd, len);
let rcmd = match String::from_utf16(rcmd) {
Ok(cmd) => cmd,
Err(err) => {
tt_error!(es.status, "command was not valid UTF-16"; err.into());
return -1;
}
};
libc::c_int::from(es.shell_escape(&rcmd))
}
/// Different types of files that can be opened by TeX engines
///
/// This enumeration is used to guess filename extensions to try when looking
/// for a file to open.
///
/// cbindgen:rename-all=ScreamingSnakeCase
#[derive(Clone, Copy, Debug)]
#[repr(C)]
pub enum FileFormat {
/// An Adobe Font Metrics file.
Afm = 4,
/// A BibTeX bibliography data file.
Bib = 6,
/// A BibTeX style file.
Bst = 7,
/// A character map data file.
Cmap = 45,
/// A configuration file.
Cnf = 8,
/// An encoding data file.
Enc = 44,
/// A TeX "format" file.
Format = 10,
/// A font-map file.
FontMap = 11,
/// A miscellaneous font file.
MiscFonts = 41,
/// An OFM font metrics file.
Ofm = 20,
/// An OpenType font file.
OpenType = 47,
/// An OVF file.
Ovf = 23,
/// An image file.
Pict = 25,
/// A PK font file.
Pk = 1,
/// A general program data file.
ProgramData = 39,
/// An SFD file.
Sfd = 46,
/// The Tectonic primary input file.
TectonicPrimary = 59,
/// A TeX language file.
Tex = 26,
/// A TeX PostScript header file.
TexPsHeader = 30,
/// A TeX Font Metrics file.
Tfm = 3,
/// A TrueType font file.
TrueType = 36,
/// A Type1 font file.
Type1 = 32,
/// A Virtual Font file.
Vf = 33,
}
impl FileFormat {
fn extensions(&self) -> &[&str] {
match *self {
FileFormat::Afm => &["afm"],
FileFormat::Bib => &["bib"],
FileFormat::Bst => &["bst"],
FileFormat::Cmap => &[],
FileFormat::Cnf => &["cnf"],
FileFormat::Enc => &["enc"],
FileFormat::Format => &["fmt"],
FileFormat::FontMap => &["map"],
FileFormat::MiscFonts => &[],
FileFormat::Ofm => &["ofm"],
FileFormat::OpenType => &["otf", "OTF"],
FileFormat::Ovf => &["ovf", "vf"],
FileFormat::Pict => &["pdf", "jpg", "eps", "epsi"],
FileFormat::Pk => &["pk"],
FileFormat::ProgramData => &[],
FileFormat::Sfd => &["sfd"],
FileFormat::TectonicPrimary => &[],
FileFormat::Tex => &["tex", "sty", "cls", "fd", "aux", "bbl", "def", "clo", "ldf"],
FileFormat::TexPsHeader => &["pro"],
FileFormat::Tfm => &["tfm"],
FileFormat::TrueType => &["ttf", "ttc", "TTF", "TTC", "dfont"],
FileFormat::Type1 => &["pfa", "pfb"],
FileFormat::Vf => &["vf"],
}
}
}
/// Does our resulting executable link correctly?
#[test]
fn linkage() {}