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minio/cmd/posix-dirent_namelen_linux.go
Harshavardhana a8296445ad
Safely use unsafe.Pointer to avoid crashes on ARM ()
Refactor the Dirent parsing code such that when we
calculate offsets are correct based on the platform
This PR fixes a silent potential crash on ARM
architecture.
2019-08-09 08:54:11 -07:00

44 lines
1.3 KiB
Go

// +build linux,!appengine
/*
* MinIO Cloud Storage, (C) 2019 MinIO, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"bytes"
"fmt"
"syscall"
"unsafe"
)
func direntNamlen(dirent *syscall.Dirent) (uint64, error) {
const fixedHdr = uint16(unsafe.Offsetof(syscall.Dirent{}.Name))
nameBuf := (*[unsafe.Sizeof(dirent.Name)]byte)(unsafe.Pointer(&dirent.Name[0]))
const nameBufLen = uint16(len(nameBuf))
limit := dirent.Reclen - fixedHdr
if limit > nameBufLen {
limit = nameBufLen
}
// Avoid bugs in long file names
// https://github.com/golang/tools/commit/5f9a5413737ba4b4f692214aebee582b47c8be74
nameLen := bytes.IndexByte(nameBuf[:limit], 0)
if nameLen < 0 {
return 0, fmt.Errorf("failed to find terminating 0 byte in dirent")
}
return uint64(nameLen), nil
}