From 38204b63211302a77bb9ff677f6b1df9f5acd734 Mon Sep 17 00:00:00 2001
From: David Cook <divergentdave@gmail.com>
Date: Sun, 26 Jan 2020 16:45:05 -0600
Subject: [PATCH 1/3] Add shim for rename

---
 src/shims/foreign_items.rs |  5 +++++
 src/shims/fs.rs            | 28 +++++++++++++++++++++++++++-
 tests/run-pass/fs.rs       | 14 +++++++++++++-
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/src/shims/foreign_items.rs b/src/shims/foreign_items.rs
index 5b40f3c6906..2fd886ed0e8 100644
--- a/src/shims/foreign_items.rs
+++ b/src/shims/foreign_items.rs
@@ -521,6 +521,11 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
             }
 
+            "rename" => {
+                let result = this.rename(args[0], args[1])?;
+                this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
+            }
+
             "clock_gettime" => {
                 let result = this.clock_gettime(args[0], args[1])?;
                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
diff --git a/src/shims/fs.rs b/src/shims/fs.rs
index f0efc073f75..2ae215e7204 100644
--- a/src/shims/fs.rs
+++ b/src/shims/fs.rs
@@ -1,6 +1,6 @@
 use std::collections::HashMap;
 use std::convert::{TryFrom, TryInto};
-use std::fs::{remove_file, File, OpenOptions};
+use std::fs::{remove_file, rename, File, OpenOptions};
 use std::io::{Read, Seek, SeekFrom, Write};
 use std::path::PathBuf;
 use std::time::SystemTime;
@@ -582,6 +582,32 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
         this.set_last_error(ebadf)?;
         Ok((-1).into())
     }
+
+    fn rename(
+        &mut self,
+        oldpath_op: OpTy<'tcx, Tag>,
+        newpath_op: OpTy<'tcx, Tag>,
+    ) -> InterpResult<'tcx, i32> {
+        let this = self.eval_context_mut();
+
+        this.check_no_isolation("rename")?;
+
+        let oldpath_scalar = this.read_scalar(oldpath_op)?.not_undef()?;
+        let newpath_scalar = this.read_scalar(newpath_op)?.not_undef()?;
+
+        if this.is_null(oldpath_scalar)? || this.is_null(newpath_scalar)? {
+            let efault = this.eval_libc("EFAULT")?;
+            this.set_last_error(efault)?;
+            return Ok(-1);
+        }
+
+        let oldpath = this.read_os_str_from_c_str(oldpath_scalar)?;
+        let newpath = this.read_os_str_from_c_str(newpath_scalar)?;
+
+        let result = rename(oldpath, newpath).map(|_| 0);
+
+        this.try_unwrap_io_result(result)
+    }
 }
 
 /// Extracts the number of seconds and nanoseconds elapsed between `time` and the unix epoch when
diff --git a/tests/run-pass/fs.rs b/tests/run-pass/fs.rs
index 7483bf3ec8b..9e1891adf34 100644
--- a/tests/run-pass/fs.rs
+++ b/tests/run-pass/fs.rs
@@ -1,7 +1,7 @@
 // ignore-windows: File handling is not implemented yet
 // compile-flags: -Zmiri-disable-isolation
 
-use std::fs::{File, remove_file};
+use std::fs::{File, remove_file, rename};
 use std::io::{Read, Write, ErrorKind, Result, Seek, SeekFrom};
 use std::path::{PathBuf, Path};
 
@@ -82,6 +82,18 @@ fn main() {
     // Removing file should succeed.
     remove_file(&path).unwrap();
 
+    // Renaming a file should succeed.
+    let path1 = tmp.join("rename_source.txt");
+    let path2 = tmp.join("rename_destination.txt");
+    // Clean files for robustness.
+    remove_file(&path1).ok();
+    remove_file(&path2).ok();
+    let file = File::create(&path1).unwrap();
+    drop(file);
+    rename(&path1, &path2).unwrap();
+    assert!(path2.metadata().unwrap().is_file());
+    remove_file(&path2).ok();
+
     // The two following tests also check that the `__errno_location()` shim is working properly.
     // Opening a non-existing file should fail with a "not found" error.
     assert_eq!(ErrorKind::NotFound, File::open(&path).unwrap_err().kind());

From f7e085764445c679bdc2694733119f2b5aeedf8e Mon Sep 17 00:00:00 2001
From: David Cook <divergentdave@gmail.com>
Date: Sat, 8 Feb 2020 22:40:46 -0600
Subject: [PATCH 2/3] Test that src path of rename is no longer a file

---
 tests/run-pass/fs.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/run-pass/fs.rs b/tests/run-pass/fs.rs
index 9e1891adf34..e9132fbd61d 100644
--- a/tests/run-pass/fs.rs
+++ b/tests/run-pass/fs.rs
@@ -91,6 +91,7 @@ fn main() {
     let file = File::create(&path1).unwrap();
     drop(file);
     rename(&path1, &path2).unwrap();
+    assert_eq!(ErrorKind::NotFound, path1.metadata().unwrap_err().kind());
     assert!(path2.metadata().unwrap().is_file());
     remove_file(&path2).ok();
 

From 91868125a519db341f86410590b959b10de03f11 Mon Sep 17 00:00:00 2001
From: David Cook <divergentdave@gmail.com>
Date: Fri, 14 Feb 2020 08:19:16 -0600
Subject: [PATCH 3/3] Removing file after rename must succeed

Co-Authored-By: Ralf Jung <post@ralfj.de>
---
 tests/run-pass/fs.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/run-pass/fs.rs b/tests/run-pass/fs.rs
index e9132fbd61d..71c6e854f7c 100644
--- a/tests/run-pass/fs.rs
+++ b/tests/run-pass/fs.rs
@@ -93,7 +93,7 @@ fn main() {
     rename(&path1, &path2).unwrap();
     assert_eq!(ErrorKind::NotFound, path1.metadata().unwrap_err().kind());
     assert!(path2.metadata().unwrap().is_file());
-    remove_file(&path2).ok();
+    remove_file(&path2).unwrap();
 
     // The two following tests also check that the `__errno_location()` shim is working properly.
     // Opening a non-existing file should fail with a "not found" error.