rust/src/shims/env.rs
2019-08-29 15:03:10 -05:00

115 lines
3.8 KiB
Rust

use std::collections::HashMap;
use rustc::ty::layout::{Size};
use rustc_mir::interpret::{Pointer, Memory};
use crate::stacked_borrows::Tag;
use crate::*;
#[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: HashMap<Vec<u8>, Pointer<Tag>>,
}
impl EnvVars {
pub(crate) fn init<'mir, 'tcx>(
ecx: &mut InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
mut excluded_env_vars: Vec<String>,
) {
// Exclude `TERM` var to avoid terminfo trying to open the termcap file.
excluded_env_vars.push("TERM".to_owned());
if ecx.machine.communicate {
for (name, value) in std::env::vars() {
if !excluded_env_vars.contains(&name) {
let var_ptr = alloc_env_var(name.as_bytes(), value.as_bytes(), ecx.memory_mut());
ecx.machine.env_vars.map.insert(name.into_bytes(), var_ptr);
}
}
}
}
}
fn alloc_env_var<'mir, 'tcx>(
name: &[u8],
value: &[u8],
memory: &mut Memory<'mir, 'tcx, Evaluator<'tcx>>,
) -> Pointer<Tag> {
let mut bytes = name.to_vec();
bytes.push(b'=');
bytes.extend_from_slice(value);
bytes.push(0);
memory.allocate_static_bytes(bytes.as_slice(), MiriMemoryKind::Env.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.memory().read_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::Ptr(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 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.memory().read_c_str(value_ptr)?;
let mut new = None;
if !this.is_null(name_ptr)? {
let name = this.memory().read_c_str(name_ptr)?;
if !name.is_empty() && !name.contains(&b'=') {
new = Some((name.to_owned(), value.to_owned()));
}
}
if let Some((name, value)) = new {
let var_ptr = alloc_env_var(&name, &value, this.memory_mut());
if let Some(var) = this.machine.env_vars.map.insert(name.to_owned(), var_ptr) {
this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.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.memory().read_c_str(name_ptr)?.to_owned();
if !name.is_empty() && !name.contains(&b'=') {
success = Some(this.machine.env_vars.map.remove(&name));
}
}
if let Some(old) = success {
if let Some(var) = old {
this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
}
Ok(0)
} else {
Ok(-1)
}
}
}