rust/src/shims/env.rs
2020-03-02 22:36:15 +01:00

154 lines
5.2 KiB
Rust

use std::ffi::{OsString, OsStr};
use std::env;
use crate::stacked_borrows::Tag;
use crate::*;
use rustc_data_structures::fx::FxHashMap;
use rustc::ty::layout::Size;
use rustc_mir::interpret::Pointer;
#[derive(Default)]
pub struct EnvVars {
/// Stores pointers to the environment variables. These variables must be stored as
/// null-terminated C strings with the `"{name}={value}"` format.
map: FxHashMap<OsString, Pointer<Tag>>,
}
impl EnvVars {
pub(crate) fn init<'mir, 'tcx>(
ecx: &mut InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
excluded_env_vars: Vec<String>,
) {
if ecx.machine.communicate {
for (name, value) in env::vars() {
if !excluded_env_vars.contains(&name) {
let var_ptr =
alloc_env_var_as_c_str(name.as_ref(), value.as_ref(), ecx);
ecx.machine.env_vars.map.insert(OsString::from(name), var_ptr);
}
}
}
}
}
fn alloc_env_var_as_c_str<'mir, 'tcx>(
name: &OsStr,
value: &OsStr,
ecx: &mut InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
) -> Pointer<Tag> {
let mut name_osstring = name.to_os_string();
name_osstring.push("=");
name_osstring.push(value);
ecx.alloc_os_str_as_c_str(name_osstring.as_os_str(), MiriMemoryKind::Machine.into())
}
impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
fn getenv(&mut self, name_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, Scalar<Tag>> {
let this = self.eval_context_mut();
let name_ptr = this.read_scalar(name_op)?.not_undef()?;
let name = this.read_os_str_from_c_str(name_ptr)?;
Ok(match this.machine.env_vars.map.get(name) {
// The offset is used to strip the "{name}=" part of the string.
Some(var_ptr) => {
Scalar::from(var_ptr.offset(Size::from_bytes(name.len() as u64 + 1), this)?)
}
None => Scalar::ptr_null(&*this.tcx),
})
}
fn setenv(
&mut self,
name_op: OpTy<'tcx, Tag>,
value_op: OpTy<'tcx, Tag>,
) -> InterpResult<'tcx, i32> {
let mut this = self.eval_context_mut();
let name_ptr = this.read_scalar(name_op)?.not_undef()?;
let value_ptr = this.read_scalar(value_op)?.not_undef()?;
let value = this.read_os_str_from_c_str(value_ptr)?;
let mut new = None;
if !this.is_null(name_ptr)? {
let name = this.read_os_str_from_c_str(name_ptr)?;
if !name.is_empty() && !name.to_string_lossy().contains('=') {
new = Some((name.to_owned(), value.to_owned()));
}
}
if let Some((name, value)) = new {
let var_ptr = alloc_env_var_as_c_str(&name, &value, &mut this);
if let Some(var) = this.machine.env_vars.map.insert(name.to_owned(), var_ptr) {
this.memory
.deallocate(var, None, MiriMemoryKind::Machine.into())?;
}
Ok(0)
} else {
Ok(-1)
}
}
fn unsetenv(&mut self, name_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
let name_ptr = this.read_scalar(name_op)?.not_undef()?;
let mut success = None;
if !this.is_null(name_ptr)? {
let name = this.read_os_str_from_c_str(name_ptr)?.to_owned();
if !name.is_empty() && !name.to_string_lossy().contains('=') {
success = Some(this.machine.env_vars.map.remove(&name));
}
}
if let Some(old) = success {
if let Some(var) = old {
this.memory
.deallocate(var, None, MiriMemoryKind::Machine.into())?;
}
Ok(0)
} else {
Ok(-1)
}
}
fn getcwd(
&mut self,
buf_op: OpTy<'tcx, Tag>,
size_op: OpTy<'tcx, Tag>,
) -> InterpResult<'tcx, Scalar<Tag>> {
let this = self.eval_context_mut();
this.check_no_isolation("getcwd")?;
let buf = this.read_scalar(buf_op)?.not_undef()?;
let size = this.read_scalar(size_op)?.to_machine_usize(&*this.tcx)?;
// If we cannot get the current directory, we return null
match env::current_dir() {
Ok(cwd) => {
if this.write_os_str_to_c_str(&OsString::from(cwd), buf, size)?.0 {
return Ok(buf);
}
let erange = this.eval_libc("ERANGE")?;
this.set_last_error(erange)?;
}
Err(e) => this.set_last_error_from_io_error(e)?,
}
Ok(Scalar::ptr_null(&*this.tcx))
}
fn chdir(&mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
this.check_no_isolation("chdir")?;
let path = this.read_os_str_from_c_str(this.read_scalar(path_op)?.not_undef()?)?;
match env::set_current_dir(path) {
Ok(()) => Ok(0),
Err(e) => {
this.set_last_error_from_io_error(e)?;
Ok(-1)
}
}
}
}