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Add helper 'alloc_os_str_as_c_str' and use it in env_var emulation

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This commit is contained in:
JOE1994 2019-12-27 20:32:20 -05:00
parent 34d8ec896d
commit a4bd68a45f
3 changed files with 47 additions and 22 deletions
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14
src/helpers.rs
View file

@ -497,6 +497,20 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
.write_bytes(scalar, bytes.iter().copied().chain(iter::once(0u8)))?;
Ok(true)
}
fn alloc_os_str_as_c_str(
&mut self,
os_str: &OsStr,
memkind: MemoryKind<MiriMemoryKind>
) -> Pointer<Tag> {
let size = os_str.len() as u64 + 1; // 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);
self.write_os_str_to_c_str(os_str, arg_place.ptr, size).unwrap();
arg_place.ptr.assert_ptr()
}
}
pub fn immty_from_int_checked<'tcx>(

43
src/shims/env.rs
View file

@ -1,18 +1,18 @@
use std::collections::HashMap;
use std::ffi::OsString;
use std::ffi::{OsString, OsStr};
use std::env;
use crate::stacked_borrows::Tag;
use crate::*;
use rustc::ty::layout::Size;
use rustc_mir::interpret::{Memory, Pointer};
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: HashMap<Vec<u8>, Pointer<Tag>>,
map: HashMap<OsString, Pointer<Tag>>,
}
impl EnvVars {
@ -30,24 +30,23 @@ impl EnvVars {
for (name, value) in env::vars() {
if !excluded_env_vars.contains(&name) {
let var_ptr =
alloc_env_var(name.as_bytes(), value.as_bytes(), &mut ecx.memory);
ecx.machine.env_vars.map.insert(name.into_bytes(), 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<'mir, 'tcx>(
name: &[u8],
value: &[u8],
memory: &mut Memory<'mir, 'tcx, Evaluator<'tcx>>,
fn alloc_env_var_as_c_str<'mir, 'tcx>(
name: &OsStr,
value: &OsStr,
ecx: &mut InterpCx<'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())
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::Env.into())
}
impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
@ -56,7 +55,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
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)?;
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) => {
@ -71,20 +70,20 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
name_op: OpTy<'tcx, Tag>,
value_op: OpTy<'tcx, Tag>,
) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
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.memory.read_c_str(value_ptr)?;
let value = this.read_os_str_from_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'=') {
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(&name, &value, &mut this.memory);
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::Env.into())?;
@ -101,8 +100,8 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
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'=') {
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));
}
}

12
src/shims/foreign_items.rs
View file

@ -956,10 +956,22 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
this.write_null(dest)?;
}
"GetEnvironmentVariableW" => {
// args[0] : LPCWSTR lpName (32-bit ptr to a const string of 16-bit Unicode chars)
// args[1] : LPWSTR lpBuffer (32-bit pointer to a string of 16-bit Unicode chars)
// lpBuffer : ptr to buffer that receives contents of the env_var as a null-terminated string.
// Return `# of chars` stored in the buffer pointed to by lpBuffer, excluding null-terminator.
// Return 0 upon failure.
// This is not the env var you are looking for.
this.set_last_error(Scalar::from_u32(203))?; // ERROR_ENVVAR_NOT_FOUND
this.write_null(dest)?;
}
"SetEnvironmentVariableW" => {
// args[0] : LPCWSTR lpName (32-bit ptr to a const string of 16-bit Unicode chars)
// args[1] : LPCWSTR lpValue (32-bit ptr to a const string of 16-bit Unicode chars)
// Return nonzero if success, else return 0.
throw_unsup_format!("can't set environment variable on Windows");
}
"GetCommandLineW" => {
this.write_scalar(
this.machine.cmd_line.expect("machine must be initialized"),