Auto merge of #1838 - atsmtat:fs-isolation, r=RalfJung

Fix use of deprecated `check_no_isolation` in posix fs shims

Update posix fs shims to use new API `reject_in_isolation`, which
allows rejection with error code instead of always forcing abort.
Error code chosen for each op is the most appropriate one from the
list in corresponding syscall's manual.

Updated helper APIs to not use quotes (\`) around input name while
preparing the message. This allows callers to pass multi-word string
like -- "\`read\` from stdin".

Cc #1034

Author: bors

src/diagnostics.rs

@@ -328,7 +328,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                     CreatedAlloc(AllocId(id)) => format!("created allocation with id {}", id),
                     FreedAlloc(AllocId(id)) => format!("freed allocation with id {}", id),
                     RejectedIsolatedOp(ref op) =>
-                        format!("`{}` was made to return an error due to isolation", op),
+                        format!("{} was made to return an error due to isolation", op),
                 };
 
                 let (title, diag_level) = match e {

src/helpers.rs

@@ -409,7 +409,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
             RejectOpWith::WarningWithoutBacktrace => {
                 this.tcx
                     .sess
-                    .warn(&format!("`{}` was made to return an error due to isolation", op_name));
+                    .warn(&format!("{} was made to return an error due to isolation", op_name));
                 Ok(())
             }
             RejectOpWith::Warning => {

src/shims/env.rs

@@ -322,7 +322,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let size = this.read_scalar(&size_op)?.to_machine_usize(&*this.tcx)?;
 
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
-            this.reject_in_isolation("getcwd", reject_with)?;
+            this.reject_in_isolation("`getcwd`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
             return Ok(Pointer::null());
         }
@@ -355,7 +355,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let buf = this.read_pointer(buf_op)?;
 
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
-            this.reject_in_isolation("GetCurrentDirectoryW", reject_with)?;
+            this.reject_in_isolation("`GetCurrentDirectoryW`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
             return Ok(0);
         }
@@ -380,7 +380,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;
 
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
-            this.reject_in_isolation("chdir", reject_with)?;
+            this.reject_in_isolation("`chdir`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
 
             return Ok(-1);
@@ -408,7 +408,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         let path = this.read_path_from_wide_str(this.read_pointer(path_op)?)?;
 
         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
-            this.reject_in_isolation("SetCurrentDirectoryW", reject_with)?;
+            this.reject_in_isolation("`SetCurrentDirectoryW`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied)?;
 
             return Ok(0);