From: David Cook <divergentdave@gmail.com>
Date: Tue, 26 May 2020 00:50:06 +0000 (-0500)
Subject: Fix fsync shim for Windows hosts with RO files
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=c01bc142194ae294356ac3b5b8666c3c351f14d5;p=rust.git

Fix fsync shim for Windows hosts with RO files
---

diff --git a/src/shims/fs.rs b/src/shims/fs.rs
index 66e191e3ed4..7f1c5caaf64 100644
--- a/src/shims/fs.rs
+++ b/src/shims/fs.rs
@@ -1125,9 +1125,14 @@ fn fsync(&mut self, fd_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
         this.check_no_isolation("fsync")?;
 
         let fd = this.read_scalar(fd_op)?.to_i32()?;
-        if let Some(FileHandle { file, writable: _ }) = this.machine.file_handler.handles.get_mut(&fd) {
-            let result = file.sync_all();
-            this.try_unwrap_io_result(result.map(|_| 0i32))
+        if let Some(FileHandle { file, writable }) = this.machine.file_handler.handles.get_mut(&fd) {
+            if !*writable && cfg!(windows) {
+                // sync_all() will return an error on Windows hosts if the file is not opened for writing.
+                Ok(0i32)
+            } else {
+                let result = file.sync_all();
+                this.try_unwrap_io_result(result.map(|_| 0i32))
+            }
         } else {
             this.handle_not_found()
         }
@@ -1139,9 +1144,14 @@ fn fdatasync(&mut self, fd_op: OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
         this.check_no_isolation("fdatasync")?;
 
         let fd = this.read_scalar(fd_op)?.to_i32()?;
-        if let Some(FileHandle { file, writable: _ }) = this.machine.file_handler.handles.get_mut(&fd) {
-            let result = file.sync_data();
-            this.try_unwrap_io_result(result.map(|_| 0i32))
+        if let Some(FileHandle { file, writable }) = this.machine.file_handler.handles.get_mut(&fd) {
+            if !*writable && cfg!(windows) {
+                // sync_data() will return an error on Windows hosts if the file is not opened for writing.
+                Ok(0i32)
+            } else {
+                let result = file.sync_data();
+                this.try_unwrap_io_result(result.map(|_| 0i32))
+            }
         } else {
             this.handle_not_found()
         }