Add function to error with enabled isolation

Author: pvdrz

src/helpers.rs

@@ -304,4 +304,14 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn eval_libc_i32(&mut self, name: &str) -> InterpResult<'tcx, i32> {
         self.eval_libc(name)?.to_i32()
     }
+
+    /// Helper function used inside the shims of foreign functions to check that isolation is
+    /// disabled. It returns an error using the `name` of the foreign function if this is not the
+    /// case.
+    fn check_no_isolation(&mut self, name: &str) -> InterpResult<'tcx> {
+        if !self.eval_context_mut().machine.communicate {
+            throw_unsup_format!("`{}` not available when isolation is enabled. Pass the flag `-Zmiri-disable-isolation` to disable it.", name)
+        }
+        Ok(())
+    }
 }

src/shims/env.rs

@@ -120,9 +120,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, Scalar<Tag>> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`getcwd` not available when isolation is enabled")
-        }
+        this.check_no_isolation("getcwd")?;
 
         let tcx = &{ this.tcx.tcx };
 
@@ -158,9 +156,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn chdir(&mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`chdir` not available when isolation is enabled")
-        }
+        this.check_no_isolation("chdir")?;
 
         let path_bytes = this
             .memory()

src/shims/fs.rs

@@ -36,9 +36,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`open` not available when isolation is enabled")
-        }
+        this.check_no_isolation("open")?;
 
         let flag = this.read_scalar(flag_op)?.to_i32()?;
 
@@ -91,9 +89,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`fcntl` not available when isolation is enabled")
-        }
+        this.check_no_isolation("fcntl")?;
 
         let fd = this.read_scalar(fd_op)?.to_i32()?;
         let cmd = this.read_scalar(cmd_op)?.to_i32()?;
@@ -126,9 +122,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn close(&mut self, fd_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`close` not available when isolation is enabled")
-        }
+        this.check_no_isolation("close")?;
 
         let fd = this.read_scalar(fd_op)?.to_i32()?;
 
@@ -145,9 +139,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, i64> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`read` not available when isolation is enabled")
-        }
+        this.check_no_isolation("read")?;
 
         let tcx = &{ this.tcx.tcx };
 
@@ -182,9 +174,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     ) -> InterpResult<'tcx, i64> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`write` not available when isolation is enabled")
-        }
+        this.check_no_isolation("write")?;
 
         let tcx = &{ this.tcx.tcx };
 
@@ -210,9 +200,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
     fn unlink( &mut self, path_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
 
-        if !this.machine.communicate {
-            throw_unsup_format!("`write` not available when isolation is enabled")
-        }
+        this.check_no_isolation("unlink")?;
 
         let path_bytes = this
             .memory()