rust/src/shims/os_str.rs

269 lines
11 KiB
Rust

use std::borrow::Cow;
use std::convert::TryFrom;
use std::ffi::{OsStr, OsString};
use std::iter;
use std::path::{Path, PathBuf};
#[cfg(unix)]
use std::os::unix::ffi::{OsStrExt, OsStringExt};
#[cfg(windows)]
use std::os::windows::ffi::{OsStrExt, OsStringExt};
use rustc_target::abi::LayoutOf;
use crate::*;
/// Represent how path separator conversion should be done.
enum Pathconversion {
HostToTarget,
TargetToHost,
}
/// Perform path separator conversion if needed.
fn convert_path_separator<'a>(
os_str: Cow<'a, OsStr>,
target_os: &str,
direction: Pathconversion,
) -> Cow<'a, OsStr> {
#[cfg(windows)]
return if target_os == "windows" {
// Windows-on-Windows, all fine.
os_str
} else {
// Unix target, Windows host.
let (from, to) = match direction {
Pathconversion::HostToTarget => ('\\', '/'),
Pathconversion::TargetToHost => ('/', '\\'),
};
let converted = os_str
.encode_wide()
.map(|wchar| if wchar == from as u16 { to as u16 } else { wchar })
.collect::<Vec<_>>();
Cow::Owned(OsString::from_wide(&converted))
};
#[cfg(unix)]
return if target_os == "windows" {
// Windows target, Unix host.
let (from, to) = match direction {
Pathconversion::HostToTarget => ('/', '\\'),
Pathconversion::TargetToHost => ('\\', '/'),
};
let converted = os_str
.as_bytes()
.iter()
.map(|&wchar| if wchar == from as u8 { to as u8 } else { wchar })
.collect::<Vec<_>>();
Cow::Owned(OsString::from_vec(converted))
} else {
// Unix-on-Unix, all is fine.
os_str
};
}
impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
/// Helper function to read an OsString from a null-terminated sequence of bytes, which is what
/// the Unix APIs usually handle.
fn read_os_str_from_c_str<'a>(&'a self, scalar: Scalar<Tag>) -> InterpResult<'tcx, &'a OsStr>
where
'tcx: 'a,
'mir: 'a,
{
#[cfg(unix)]
fn bytes_to_os_str<'tcx, 'a>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
Ok(OsStr::from_bytes(bytes))
}
#[cfg(not(unix))]
fn bytes_to_os_str<'tcx, 'a>(bytes: &'a [u8]) -> InterpResult<'tcx, &'a OsStr> {
let s = std::str::from_utf8(bytes)
.map_err(|_| err_unsup_format!("{:?} is not a valid utf-8 string", bytes))?;
Ok(OsStr::new(s))
}
let this = self.eval_context_ref();
let bytes = this.memory.read_c_str(scalar)?;
bytes_to_os_str(bytes)
}
/// Helper function to read an OsString from a 0x0000-terminated sequence of u16,
/// which is what the Windows APIs usually handle.
fn read_os_str_from_wide_str<'a>(&'a self, scalar: Scalar<Tag>) -> InterpResult<'tcx, OsString>
where
'tcx: 'a,
'mir: 'a,
{
#[cfg(windows)]
pub fn u16vec_to_osstring<'tcx, 'a>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
Ok(OsString::from_wide(&u16_vec[..]))
}
#[cfg(not(windows))]
pub fn u16vec_to_osstring<'tcx, 'a>(u16_vec: Vec<u16>) -> InterpResult<'tcx, OsString> {
let s = String::from_utf16(&u16_vec[..])
.map_err(|_| err_unsup_format!("{:?} is not a valid utf-16 string", u16_vec))?;
Ok(s.into())
}
let u16_vec = self.eval_context_ref().memory.read_wide_str(scalar)?;
u16vec_to_osstring(u16_vec)
}
/// Helper function to write an OsStr as a null-terminated sequence of bytes, which is what
/// the Unix APIs usually handle. This function returns `Ok((false, length))` without trying
/// to write if `size` is not large enough to fit the contents of `os_string` plus a null
/// terminator. It returns `Ok((true, length))` if the writing process was successful. The
/// string length returned does not include the null terminator.
fn write_os_str_to_c_str(
&mut self,
os_str: &OsStr,
scalar: Scalar<Tag>,
size: u64,
) -> InterpResult<'tcx, (bool, u64)> {
#[cfg(unix)]
fn os_str_to_bytes<'tcx, 'a>(os_str: &'a OsStr) -> InterpResult<'tcx, &'a [u8]> {
Ok(os_str.as_bytes())
}
#[cfg(not(unix))]
fn os_str_to_bytes<'tcx, 'a>(os_str: &'a OsStr) -> InterpResult<'tcx, &'a [u8]> {
// On non-unix platforms the best we can do to transform bytes from/to OS strings is to do the
// intermediate transformation into strings. Which invalidates non-utf8 paths that are actually
// valid.
os_str
.to_str()
.map(|s| s.as_bytes())
.ok_or_else(|| err_unsup_format!("{:?} is not a valid utf-8 string", os_str).into())
}
let bytes = os_str_to_bytes(os_str)?;
// If `size` is smaller or equal than `bytes.len()`, writing `bytes` plus the required null
// terminator to memory using the `ptr` pointer would cause an out-of-bounds access.
let string_length = u64::try_from(bytes.len()).unwrap();
if size <= string_length {
return Ok((false, string_length));
}
self.eval_context_mut()
.memory
.write_bytes(scalar, bytes.iter().copied().chain(iter::once(0u8)))?;
Ok((true, string_length))
}
/// Helper function to write an OsStr as a 0x0000-terminated u16-sequence, which is what
/// the Windows APIs usually handle. This function returns `Ok((false, length))` without trying
/// to write if `size` is not large enough to fit the contents of `os_string` plus a null
/// terminator. It returns `Ok((true, length))` if the writing process was successful. The
/// string length returned does not include the null terminator.
fn write_os_str_to_wide_str(
&mut self,
os_str: &OsStr,
scalar: Scalar<Tag>,
size: u64,
) -> InterpResult<'tcx, (bool, u64)> {
#[cfg(windows)]
fn os_str_to_u16vec<'tcx>(os_str: &OsStr) -> InterpResult<'tcx, Vec<u16>> {
Ok(os_str.encode_wide().collect())
}
#[cfg(not(windows))]
fn os_str_to_u16vec<'tcx>(os_str: &OsStr) -> InterpResult<'tcx, Vec<u16>> {
// On non-Windows platforms the best we can do to transform Vec<u16> from/to OS strings is to do the
// intermediate transformation into strings. Which invalidates non-utf8 paths that are actually
// valid.
os_str
.to_str()
.map(|s| s.encode_utf16().collect())
.ok_or_else(|| err_unsup_format!("{:?} is not a valid utf-8 string", os_str).into())
}
let u16_vec = os_str_to_u16vec(os_str)?;
// If `size` is smaller or equal than `bytes.len()`, writing `bytes` plus the required
// 0x0000 terminator to memory would cause an out-of-bounds access.
let string_length = u64::try_from(u16_vec.len()).unwrap();
if size <= string_length {
return Ok((false, string_length));
}
// Store the UTF-16 string.
self.eval_context_mut()
.memory
.write_u16s(scalar, u16_vec.into_iter().chain(iter::once(0x0000)))?;
Ok((true, string_length))
}
/// Allocate enough memory to store the given `OsStr` as a null-terminated sequence of bytes.
fn alloc_os_str_as_c_str(
&mut self,
os_str: &OsStr,
memkind: MemoryKind<MiriMemoryKind>,
) -> Pointer<Tag> {
let size = u64::try_from(os_str.len()).unwrap().checked_add(1).unwrap(); // Make space for `0` terminator.
let this = self.eval_context_mut();
let arg_type = this.tcx.mk_array(this.tcx.types.u8, size);
let arg_place = this.allocate(this.layout_of(arg_type).unwrap(), memkind);
assert!(self.write_os_str_to_c_str(os_str, arg_place.ptr, size).unwrap().0);
arg_place.ptr.assert_ptr()
}
/// Allocate enough memory to store the given `OsStr` as a null-terminated sequence of `u16`.
fn alloc_os_str_as_wide_str(
&mut self,
os_str: &OsStr,
memkind: MemoryKind<MiriMemoryKind>,
) -> Pointer<Tag> {
let size = u64::try_from(os_str.len()).unwrap().checked_add(1).unwrap(); // Make space for `0x0000` terminator.
let this = self.eval_context_mut();
let arg_type = this.tcx.mk_array(this.tcx.types.u16, size);
let arg_place = this.allocate(this.layout_of(arg_type).unwrap(), memkind);
assert!(self.write_os_str_to_wide_str(os_str, arg_place.ptr, size).unwrap().0);
arg_place.ptr.assert_ptr()
}
/// Read a null-terminated sequence of bytes, and perform path separator conversion if needed.
fn read_path_from_c_str<'a>(&'a self, scalar: Scalar<Tag>) -> InterpResult<'tcx, Cow<'a, Path>>
where
'tcx: 'a,
'mir: 'a,
{
let this = self.eval_context_ref();
let os_str = this.read_os_str_from_c_str(scalar)?;
Ok(match convert_path_separator(Cow::Borrowed(os_str), &this.tcx.sess.target.target.target_os, Pathconversion::TargetToHost) {
Cow::Borrowed(x) => Cow::Borrowed(Path::new(x)),
Cow::Owned(y) => Cow::Owned(PathBuf::from(y)),
})
}
/// Read a null-terminated sequence of `u16`s, and perform path separator conversion if needed.
fn read_path_from_wide_str(&self, scalar: Scalar<Tag>) -> InterpResult<'tcx, PathBuf> {
let this = self.eval_context_ref();
let os_str = this.read_os_str_from_wide_str(scalar)?;
Ok(convert_path_separator(Cow::Owned(os_str), &this.tcx.sess.target.target.target_os, Pathconversion::TargetToHost).into_owned().into())
}
/// Write a Path to the machine memory (as a null-terminated sequence of bytes),
/// adjusting path separators if needed.
fn write_path_to_c_str(
&mut self,
path: &Path,
scalar: Scalar<Tag>,
size: u64,
) -> InterpResult<'tcx, (bool, u64)> {
let this = self.eval_context_mut();
let os_str = convert_path_separator(Cow::Borrowed(path.as_os_str()), &this.tcx.sess.target.target.target_os, Pathconversion::HostToTarget);
this.write_os_str_to_c_str(&os_str, scalar, size)
}
/// Write a Path to the machine memory (as a null-terminated sequence of `u16`s),
/// adjusting path separators if needed.
fn write_path_to_wide_str(
&mut self,
path: &Path,
scalar: Scalar<Tag>,
size: u64,
) -> InterpResult<'tcx, (bool, u64)> {
let this = self.eval_context_mut();
let os_str = convert_path_separator(Cow::Borrowed(path.as_os_str()), &this.tcx.sess.target.target.target_os, Pathconversion::HostToTarget);
this.write_os_str_to_wide_str(&os_str, scalar, size)
}
}