summaryrefslogtreecommitdiffhomepage
path: root/pkg/sentry/fs/ext/utils.go
diff options
context:
space:
mode:
Diffstat (limited to 'pkg/sentry/fs/ext/utils.go')
-rw-r--r--pkg/sentry/fs/ext/utils.go109
1 files changed, 0 insertions, 109 deletions
diff --git a/pkg/sentry/fs/ext/utils.go b/pkg/sentry/fs/ext/utils.go
deleted file mode 100644
index 71e46b2c4..000000000
--- a/pkg/sentry/fs/ext/utils.go
+++ /dev/null
@@ -1,109 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// 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 ext
-
-import (
- "encoding/binary"
- "io"
-
- "gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
- "gvisor.dev/gvisor/pkg/syserror"
-)
-
-// readFromDisk performs a binary read from disk into the given struct from
-// the absolute offset provided.
-//
-// All disk reads should use this helper so we avoid reading from stale
-// previously used offsets. This function forces the offset parameter.
-//
-// Precondition: Must have mutual exclusion on device fd.
-func readFromDisk(dev io.ReadSeeker, abOff int64, v interface{}) error {
- if _, err := dev.Seek(abOff, io.SeekStart); err != nil {
- return syserror.EIO
- }
-
- if err := binary.Read(dev, binary.LittleEndian, v); err != nil {
- return syserror.EIO
- }
-
- return nil
-}
-
-// readSuperBlock reads the SuperBlock from block group 0 in the underlying
-// device. There are three versions of the superblock. This function identifies
-// and returns the correct version.
-//
-// Precondition: Must have mutual exclusion on device fd.
-func readSuperBlock(dev io.ReadSeeker) (disklayout.SuperBlock, error) {
- var sb disklayout.SuperBlock = &disklayout.SuperBlockOld{}
- if err := readFromDisk(dev, disklayout.SbOffset, sb); err != nil {
- return nil, err
- }
- if sb.Revision() == disklayout.OldRev {
- return sb, nil
- }
-
- sb = &disklayout.SuperBlock32Bit{}
- if err := readFromDisk(dev, disklayout.SbOffset, sb); err != nil {
- return nil, err
- }
- if !sb.IncompatibleFeatures().Is64Bit {
- return sb, nil
- }
-
- sb = &disklayout.SuperBlock64Bit{}
- if err := readFromDisk(dev, disklayout.SbOffset, sb); err != nil {
- return nil, err
- }
- return sb, nil
-}
-
-// blockGroupsCount returns the number of block groups in the ext fs.
-func blockGroupsCount(sb disklayout.SuperBlock) uint64 {
- blocksCount := sb.BlocksCount()
- blocksPerGroup := uint64(sb.BlocksPerGroup())
-
- // Round up the result. float64 can compromise precision so do it manually.
- bgCount := blocksCount / blocksPerGroup
- if blocksCount%blocksPerGroup != 0 {
- bgCount++
- }
-
- return bgCount
-}
-
-// readBlockGroups reads the block group descriptor table from block group 0 in
-// the underlying device.
-//
-// Precondition: Must have mutual exclusion on device fd.
-func readBlockGroups(dev io.ReadSeeker, sb disklayout.SuperBlock) ([]disklayout.BlockGroup, error) {
- bgCount := blockGroupsCount(sb)
- bgdSize := uint64(sb.BgDescSize())
- is64Bit := sb.IncompatibleFeatures().Is64Bit
- bgds := make([]disklayout.BlockGroup, bgCount)
-
- for i, off := uint64(0), uint64(sb.FirstDataBlock()+1)*sb.BlockSize(); i < bgCount; i, off = i+1, off+bgdSize {
- if is64Bit {
- bgds[i] = &disklayout.BlockGroup64Bit{}
- } else {
- bgds[i] = &disklayout.BlockGroup32Bit{}
- }
-
- if err := readFromDisk(dev, int64(off), bgds[i]); err != nil {
- return nil, err
- }
- }
- return bgds, nil
-}