simplify attrs for sshFxpOpenPacket

server.go

@@ -462,85 +462,20 @@ func (p *sshFxpOpenPacket) respond(svr *Server) responsePacket {
 		osFlags |= os.O_EXCL
 	}
 
-	name := svr.toLocalPath(p.Path)
 	mode := os.FileMode(0o644)
-
-	var applyAttrs []func(*os.File) error
-
-	// Both `sshFileXferAttrPermissions` and `sshFileXferAttrACmodTime` are set
-	// by e.g. `sftp`. Just in case, we handle all other cases as well.
-	// Only apply for newly created files.
-	var err error
-	useAttrs := true
-	if _, err := os.Stat(name); err == nil {
-		useAttrs = false
-	}
-	if b, ok := p.Attrs.([]byte); useAttrs && ok {
-		if (p.Flags & sshFileXferAttrSize) != 0 {
-			var size uint64
-			if size, b, err = unmarshalUint64Safe(b); err == nil {
-				applyAttrs = append(applyAttrs, func(f *os.File) error {
-					return f.Truncate(int64(size))
-				})
-			}
-		}
-		if err != nil {
-			return statusFromError(p.ID, err)
-		}
-		if (p.Flags & sshFileXferAttrUIDGID) != 0 {
-			var uid uint32
-			var gid uint32
-			if uid, b, err = unmarshalUint32Safe(b); err != nil {
-			} else if gid, b, err = unmarshalUint32Safe(b); err != nil {
-			} else {
-				applyAttrs = append(applyAttrs, func(f *os.File) error {
-					return f.Chown(int(uid), int(gid))
-				})
-			}
-		}
-		if err != nil {
-			return statusFromError(p.ID, err)
-		}
-		if (p.Flags & sshFileXferAttrPermissions) != 0 {
-			var attrMode uint32
-			if attrMode, b, err = unmarshalUint32Safe(b); err == nil {
-				// Optionally, we could apply umask here.
-				mode = os.FileMode(attrMode)
-			}
-		}
-		if err != nil {
-			return statusFromError(p.ID, err)
-		}
-		if (p.Flags & sshFileXferAttrACmodTime) != 0 {
-			var atime uint32
-			var mtime uint32
-			if atime, b, err = unmarshalUint32Safe(b); err != nil {
-			} else if mtime, _, err = unmarshalUint32Safe(b); err != nil {
-			} else {
-				atimeT := time.Unix(int64(atime), 0)
-				mtimeT := time.Unix(int64(mtime), 0)
-				applyAttrs = append(applyAttrs, func(f *os.File) error {
-					return os.Chtimes(f.Name(), atimeT, mtimeT)
-				})
-			}
-		}
-		if err != nil {
-			return statusFromError(p.ID, err)
-		}
+	// Like OpenSSH, we only handle permissions here if the file is
+	// being created. Otherwise, the permissions are ignored.
+	if b, ok := p.Attrs.([]byte); ok && (p.Flags&sshFileXferAttrPermissions) != 0 {
+		fs, _ := unmarshalFileStat(p.Flags, b)
+		mode = os.FileMode(fs.Mode)
 	}
 
+	name := svr.toLocalPath(p.Path)
 	f, err := os.OpenFile(name, osFlags, mode)
 	if err != nil {
 		return statusFromError(p.ID, err)
 	}
 
-	for _, applyAttr := range applyAttrs {
-		if err := applyAttr(f); err != nil {
-			_ = f.Close()
-			return statusFromError(p.ID, err)
-		}
-	}
-
 	handle := svr.nextHandle(f)
 	return &sshFxpHandlePacket{ID: p.ID, Handle: handle}
 }