diff --git a/src/eval.rs b/src/eval.rs
index 0970edb2b75f..ae57bcf98b96 100644
--- a/src/eval.rs
+++ b/src/eval.rs
@@ -39,7 +39,6 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
         Evaluator::new(config.communicate),
         MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
     );
-
     // Complete initialization.
     EnvVars::init(&mut ecx, config.communicate);
 
diff --git a/src/lib.rs b/src/lib.rs
index 738419c2498b..cea99d86eaa8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -33,7 +33,7 @@ pub use crate::shims::foreign_items::EvalContextExt as ForeignItemsEvalContextEx
 pub use crate::shims::intrinsics::EvalContextExt as IntrinsicsEvalContextExt;
 pub use crate::shims::tls::{EvalContextExt as TlsEvalContextExt, TlsData};
 pub use crate::shims::dlsym::{Dlsym, EvalContextExt as DlsymEvalContextExt};
-pub use crate::shims::env::EnvVars;
+pub use crate::shims::env::{EnvVars, EvalContextExt as EnvEvalContextExt};
 pub use crate::operator::EvalContextExt as OperatorEvalContextExt;
 pub use crate::range_map::RangeMap;
 pub use crate::helpers::{EvalContextExt as HelpersEvalContextExt};
diff --git a/src/shims/env.rs b/src/shims/env.rs
index 05c5fbb04309..c941bf4f50e3 100644
--- a/src/shims/env.rs
+++ b/src/shims/env.rs
@@ -22,21 +22,9 @@ impl EnvVars {
             }
         }
     }
-
-    pub(crate) fn get(&self, name: &[u8]) -> Option<&Pointer<Tag>> {
-        self.map.get(name)
-    }
-
-    pub(crate) fn unset(&mut self, name: &[u8]) -> Option<Pointer<Tag>> {
-        self.map.remove(name)
-    }
-
-    pub(crate) fn set(&mut self, name: Vec<u8>, ptr: Pointer<Tag>) -> Option<Pointer<Tag>>{
-        self.map.insert(name, ptr)
-    }
 }
 
-pub(crate) fn alloc_env_value<'mir, 'tcx>(
+fn alloc_env_value<'mir, 'tcx>(
     bytes: &[u8],
     memory: &mut Memory<'mir, 'tcx, Evaluator<'tcx>>,
 ) -> Pointer<Tag> {
@@ -58,3 +46,72 @@ pub(crate) fn alloc_env_value<'mir, 'tcx>(
     alloc.write_bytes(&tcx, trailing_zero_ptr, &[0]).unwrap();
     ptr
 }
+
+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) {
+            Some(&var) => Scalar::Ptr(var),
+            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 value_copy = alloc_env_value(&value, this.memory_mut());
+            if let Some(var) = this.machine.env_vars.map.insert(name.to_owned(), value_copy) {
+                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)
+        }
+    }
+}
diff --git a/src/shims/foreign_items.rs b/src/shims/foreign_items.rs
index 2d2b917eb275..59e7673dcab5 100644
--- a/src/shims/foreign_items.rs
+++ b/src/shims/foreign_items.rs
@@ -8,7 +8,6 @@ use syntax::attr;
 use syntax::symbol::sym;
 
 use crate::*;
-use crate::shims::env::alloc_env_value;
 
 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
@@ -423,60 +422,18 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             }
 
             "getenv" => {
-                let result = {
-                    let name_ptr = this.read_scalar(args[0])?.not_undef()?;
-                    let name = this.memory().read_c_str(name_ptr)?;
-                    match this.machine.env_vars.get(name) {
-                        Some(&var) => Scalar::Ptr(var),
-                        None => Scalar::ptr_null(&*this.tcx),
-                    }
-                };
+                let result = this.getenv(args[0])?;
                 this.write_scalar(result, dest)?;
             }
 
             "unsetenv" => {
-                let mut success = None;
-                {
-                    let name_ptr = this.read_scalar(args[0])?.not_undef()?;
-                    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.unset(&name));
-                        }
-                    }
-                }
-                if let Some(old) = success {
-                    if let Some(var) = old {
-                        this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
-                    }
-                    this.write_null(dest)?;
-                } else {
-                    this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
-                }
+                let result = this.unsetenv(args[0])?;
+                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
             }
 
             "setenv" => {
-                let mut new = None;
-                {
-                    let name_ptr = this.read_scalar(args[0])?.not_undef()?;
-                    let value_ptr = this.read_scalar(args[1])?.not_undef()?;
-                    let value = this.memory().read_c_str(value_ptr)?;
-                    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 value_copy = alloc_env_value(&value, this.memory_mut());
-                    if let Some(var) = this.machine.env_vars.set(name.to_owned(), value_copy) {
-                        this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
-                    }
-                    this.write_null(dest)?;
-                } else {
-                    this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
-                }
+                let result = this.setenv(args[0], args[1])?;
+                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
             }
 
             "write" => {