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Windows shims for env var emulation

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Shims for GetEnvironmentVariableW / SetEnvironmentVariableW /
GetEnvironmentStringsW.
Passes test 'tests/run-pass/env.rs'
This commit is contained in:
JOE1994 2020-03-13 12:45:02 -04:00
parent e2a9c7baed
commit 2fa07009f2
3 changed files with 136 additions and 16 deletions
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120
src/shims/env.rs
View File

@ -1,6 +1,7 @@
use std::ffi::{OsString, OsStr};
use std::env;
use std::convert::TryFrom;
use std::collections::hash_map::Values;
use crate::stacked_borrows::Tag;
use crate::rustc_target::abi::LayoutOf;
@ -40,6 +41,10 @@ impl<'tcx> EnvVars<'tcx> {
}
ecx.update_environ()
}
pub(super) fn values(&self) -> InterpResult<'tcx, Values<'_, OsString, Pointer<Tag>>> {
Ok(self.map.values())
}
}
fn alloc_env_var_as_c_str<'mir, 'tcx>(
@ -82,6 +87,79 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
})
}
fn getenvironmentvariablew(
&mut self,
name_op: OpTy<'tcx, Tag>, // LPCWSTR lpName
buf_op: OpTy<'tcx, Tag>, // LPWSTR lpBuffer
size_op: OpTy<'tcx, Tag>, // DWORD nSize
) -> InterpResult<'tcx, u64> {
let this = self.eval_context_mut();
this.assert_target_os("windows", "GetEnvironmentVariableW");
let name_ptr = this.read_scalar(name_op)?.not_undef()?;
let name = this.read_os_str_from_wide_str(name_ptr)?;
Ok(match this.machine.env_vars.map.get(&name) {
Some(var_ptr) => {
// The offset is used to strip the "{name}=" part of the string.
let name_offset_bytes =
u64::try_from(name.len()).unwrap().checked_add(1).unwrap().checked_mul(2).unwrap();
let var_ptr = Scalar::from(var_ptr.offset(Size::from_bytes(name_offset_bytes), this)?);
let var_size = u64::try_from(this.read_os_str_from_wide_str(var_ptr)?.len()).unwrap();
let buf_size = u64::try_from(this.read_scalar(size_op)?.to_i32()?).unwrap();
let return_val = if var_size.checked_add(1).unwrap() > buf_size {
// If lpBuffer is not large enough to hold the data, the return value is the buffer size, in characters,
// required to hold the string and its terminating null character and the contents of lpBuffer are undefined.
var_size + 1
} else {
let buf_ptr = this.read_scalar(buf_op)?.not_undef()?;
for i in 0..var_size {
this.memory.copy(
this.force_ptr(var_ptr.ptr_offset(Size::from_bytes(i) * 2, this)?)?,
this.force_ptr(buf_ptr.ptr_offset(Size::from_bytes(i) * 2, this)?)?,
Size::from_bytes(2),
true,
)?;
}
// If the function succeeds, the return value is the number of characters stored in the buffer pointed to by lpBuffer,
// not including the terminating null character.
var_size
};
return_val
}
None => {
this.set_last_error(Scalar::from_u32(203))?; // ERROR_ENVVAR_NOT_FOUND
0 // return zero upon failure
}
})
}
fn getenvironmentstringsw(&mut self) -> InterpResult<'tcx, Scalar<Tag>> {
let this = self.eval_context_mut();
this.assert_target_os("windows", "GetEnvironmentStringsW");
// Info on layout of environment blocks in Windows:
// https://docs.microsoft.com/en-us/windows/win32/procthread/environment-variables
let mut env_vars = std::ffi::OsString::new();
for &item in this.machine.env_vars.values()? {
let env_var = this.read_os_str_from_target_str(Scalar::from(item))?;
env_vars.push(env_var);
env_vars.push("\0");
}
// Allocate environment block
let tcx = this.tcx;
let env_block_size = env_vars.len().checked_add(1).unwrap();
let env_block_type = tcx.mk_array(tcx.types.u16, u64::try_from(env_block_size).unwrap());
let env_block_place = this.allocate(this.layout_of(env_block_type)?, MiriMemoryKind::WinHeap.into());
// Store environment variables to environment block
// Final null terminator(block terminator) is pushed by `write_os_str_to_wide_str`
this.write_os_str_to_wide_str(&env_vars, env_block_place, u64::try_from(env_block_size).unwrap())?;
Ok(env_block_place.ptr)
}
fn setenv(
&mut self,
name_op: OpTy<'tcx, Tag>,
@ -118,6 +196,46 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
}
}
fn setenvironmentvariablew(
&mut self,
name_op: OpTy<'tcx, Tag>, // LPCWSTR lpName,
value_op: OpTy<'tcx, Tag>, // LPCWSTR lpValue,
) -> InterpResult<'tcx, i32> {
let mut this = self.eval_context_mut();
this.assert_target_os("windows", "SetEnvironmentVariableW");
let name_ptr = this.read_scalar(name_op)?.not_undef()?;
let value_ptr = this.read_scalar(value_op)?.not_undef()?;
let mut new = None;
if !this.is_null(name_ptr)? {
let name = this.read_os_str_from_target_str(name_ptr)?;
if this.is_null(value_ptr)? {
// Delete environment variable `{name}`
if let Some(var) = this.machine.env_vars.map.remove(&name) {
this.memory.deallocate(var, None, MiriMemoryKind::Machine.into())?;
this.update_environ()?;
}
return Ok(1); // return non-zero on success
}
if !name.is_empty() && !name.to_string_lossy().contains('=') {
let value = this.read_os_str_from_target_str(value_ptr)?;
new = Some((name.to_owned(), value.to_owned()));
}
}
if let Some((name, value)) = new {
let var_ptr = alloc_env_var_as_target_str(&name, &value, &mut this)?;
if let Some(var) = this.machine.env_vars.map.insert(name, var_ptr) {
this.memory
.deallocate(var, None, MiriMemoryKind::Machine.into())?;
}
this.update_environ()?;
Ok(1) // return non-zero on success
} else {
Ok(0)
}
}
fn unsetenv(&mut self, name_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
let this = self.eval_context_mut();
let target_os = &this.tcx.sess.target.target.target_os;
@ -126,7 +244,7 @@ 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.read_os_str_from_c_str(name_ptr)?.to_owned();
let name = this.read_os_str_from_target_str(name_ptr)?.to_owned();
if !name.is_empty() && !name.to_string_lossy().contains('=') {
success = Some(this.machine.env_vars.map.remove(&name));
}

30
src/shims/foreign_items/windows.rs
View File

@ -23,22 +23,26 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
// Environment related shims
"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)?;
let result = this.getenvironmentvariablew(args[0], args[1], args[2])?;
this.write_scalar(Scalar::from_uint(result, dest.layout.size), 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");
let result = this.setenvironmentvariablew(args[0], args[1])?;
this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
}
"GetEnvironmentStringsW" => {
let result = this.getenvironmentstringsw()?;
// If the function succeeds, the return value is a pointer to the environment block of the current process.
this.write_scalar(result, dest)?;
}
"FreeEnvironmentStringsW" => {
let old_vars_ptr = this.read_scalar(args[0])?.not_undef()?;
let result = this.memory.deallocate(this.force_ptr(old_vars_ptr)?, None, MiriMemoryKind::WinHeap.into()).is_ok();
// If the function succeeds, the return value is nonzero.
this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
}
// File related shims

2
tests/run-pass/env.rs
View File

@ -1,5 +1,3 @@
//ignore-windows: TODO env var emulation stubbed out on Windows
use std::env;
fn main() {