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-rw-r--r--pkg/sentry/fs/ext/BUILD24
-rw-r--r--pkg/sentry/fs/ext/block_map_file.go61
-rw-r--r--pkg/sentry/fs/ext/dentry.go2
-rw-r--r--pkg/sentry/fs/ext/directory.go36
-rw-r--r--pkg/sentry/fs/ext/ext.go2
-rw-r--r--pkg/sentry/fs/ext/extent_file.go147
-rw-r--r--pkg/sentry/fs/ext/extent_test.go14
-rw-r--r--pkg/sentry/fs/ext/filesystem.go4
-rw-r--r--pkg/sentry/fs/ext/inline_file.go65
-rw-r--r--pkg/sentry/fs/ext/inode.go154
-rw-r--r--pkg/sentry/fs/ext/named_pipe.go40
-rw-r--r--pkg/sentry/fs/ext/regular_file.go90
-rw-r--r--pkg/sentry/fs/ext/symlink.go59
-rw-r--r--pkg/sentry/fs/ext/utils.go7
14 files changed, 587 insertions, 118 deletions
diff --git a/pkg/sentry/fs/ext/BUILD b/pkg/sentry/fs/ext/BUILD
index 2c15875f5..60f6debaf 100644
--- a/pkg/sentry/fs/ext/BUILD
+++ b/pkg/sentry/fs/ext/BUILD
@@ -1,14 +1,35 @@
package(licenses = ["notice"])
load("//tools/go_stateify:defs.bzl", "go_library", "go_test")
+load("//tools/go_generics:defs.bzl", "go_template_instance")
+
+go_template_instance(
+ name = "dentry_list",
+ out = "dentry_list.go",
+ package = "ext",
+ prefix = "dentry",
+ template = "//pkg/ilist:generic_list",
+ types = {
+ "Element": "*dentry",
+ "Linker": "*dentry",
+ },
+)
go_library(
name = "ext",
srcs = [
+ "block_map_file.go",
"dentry.go",
+ "dentry_list.go",
+ "directory.go",
"ext.go",
+ "extent_file.go",
"filesystem.go",
+ "inline_file.go",
"inode.go",
+ "named_pipe.go",
+ "regular_file.go",
+ "symlink.go",
"utils.go",
],
importpath = "gvisor.dev/gvisor/pkg/sentry/fs/ext",
@@ -17,8 +38,11 @@ go_library(
"//pkg/abi/linux",
"//pkg/binary",
"//pkg/sentry/context",
+ "//pkg/sentry/fs",
"//pkg/sentry/fs/ext/disklayout",
"//pkg/sentry/kernel/auth",
+ "//pkg/sentry/kernel/pipe",
+ "//pkg/sentry/usermem",
"//pkg/sentry/vfs",
"//pkg/syserror",
],
diff --git a/pkg/sentry/fs/ext/block_map_file.go b/pkg/sentry/fs/ext/block_map_file.go
new file mode 100644
index 000000000..eb0b35e36
--- /dev/null
+++ b/pkg/sentry/fs/ext/block_map_file.go
@@ -0,0 +1,61 @@
+// 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 (
+ "io"
+
+ "gvisor.dev/gvisor/pkg/binary"
+)
+
+// blockMapFile is a type of regular file which uses direct/indirect block
+// addressing to store file data. This was deprecated in ext4.
+type blockMapFile struct {
+ regFile regularFile
+
+ // fileToPhysBlks maps the file block numbers to the physical block numbers.
+ // the physical block number for the (i)th file block is stored in the (i)th
+ // index. This is initialized (at max) with the first 12 entries. The rest
+ // have to be read in from disk when required.
+ fileToPhysBlks []uint32
+}
+
+// Compiles only if blockMapFile implements fileReader.
+var _ fileReader = (*blockMapFile)(nil)
+
+// Read implements fileReader.getFileReader.
+func (f *blockMapFile) getFileReader(dev io.ReadSeeker, blkSize uint64, offset uint64) io.Reader {
+ panic("unimplemented")
+}
+
+// newBlockMapFile is the blockMapFile constructor. It initializes the file to
+// physical blocks map with (at most) the first 12 (direct) blocks.
+func newBlockMapFile(blkSize uint64, regFile regularFile) (*blockMapFile, error) {
+ file := &blockMapFile{regFile: regFile}
+ file.regFile.impl = file
+
+ toFill := uint64(12)
+ blksUsed := regFile.blksUsed(blkSize)
+ if blksUsed < toFill {
+ toFill = blksUsed
+ }
+
+ blkMap := regFile.inode.diskInode.Data()
+ file.fileToPhysBlks = make([]uint32, toFill)
+ for i := uint64(0); i < toFill; i++ {
+ binary.Unmarshal(blkMap[i*4:(i+1)*4], binary.LittleEndian, &file.fileToPhysBlks[i])
+ }
+ return file, nil
+}
diff --git a/pkg/sentry/fs/ext/dentry.go b/pkg/sentry/fs/ext/dentry.go
index 054fb42b6..19c9b3b2d 100644
--- a/pkg/sentry/fs/ext/dentry.go
+++ b/pkg/sentry/fs/ext/dentry.go
@@ -26,6 +26,8 @@ type dentry struct {
// share a single non-directory Inode (with hard links). inode is
// immutable.
inode *inode
+ // dentryEntry links Dentries into their parent directory.childList.
+ dentryEntry
}
// Compiles only if dentry implements vfs.DentryImpl.
diff --git a/pkg/sentry/fs/ext/directory.go b/pkg/sentry/fs/ext/directory.go
new file mode 100644
index 000000000..ab2b59e44
--- /dev/null
+++ b/pkg/sentry/fs/ext/directory.go
@@ -0,0 +1,36 @@
+// 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
+
+// directory represents a directory inode. It holds the childList in memory.
+type directory struct {
+ inode inode
+
+ // childList is a list containing (1) child Dentries and (2) fake Dentries
+ // (with inode == nil) that represent the iteration position of
+ // directoryFDs. childList is used to support directoryFD.IterDirents()
+ // efficiently. childList is immutable.
+ childList dentryList
+
+ // TODO(b/134676337): Add directory navigators.
+}
+
+// newDirectroy is the directory constructor.
+func newDirectroy(inode inode) *directory {
+ // TODO(b/134676337): initialize childList.
+ file := &directory{inode: inode}
+ file.inode.impl = file
+ return file
+}
diff --git a/pkg/sentry/fs/ext/ext.go b/pkg/sentry/fs/ext/ext.go
index 10e235fb1..2380f15da 100644
--- a/pkg/sentry/fs/ext/ext.go
+++ b/pkg/sentry/fs/ext/ext.go
@@ -88,7 +88,7 @@ func (fstype filesystemType) NewFilesystem(ctx context.Context, creds *auth.Cred
return nil, nil, err
}
- rootInode, err := fs.getOrCreateInode(disklayout.RootDirInode)
+ rootInode, err := fs.getOrCreateInode(ctx, disklayout.RootDirInode)
if err != nil {
return nil, nil, err
}
diff --git a/pkg/sentry/fs/ext/extent_file.go b/pkg/sentry/fs/ext/extent_file.go
new file mode 100644
index 000000000..86583881d
--- /dev/null
+++ b/pkg/sentry/fs/ext/extent_file.go
@@ -0,0 +1,147 @@
+// 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 (
+ "io"
+
+ "gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// extentFile is a type of regular file which uses extents to store file data.
+type extentFile struct {
+ regFile regularFile
+
+ // root is the root extent node. This lives in the 60 byte diskInode.Data().
+ // Immutable.
+ root disklayout.ExtentNode
+}
+
+// Compiles only if extentFile implements fileReader.
+var _ fileReader = (*extentFile)(nil)
+
+// Read implements fileReader.getFileReader.
+func (f *extentFile) getFileReader(dev io.ReadSeeker, blkSize uint64, offset uint64) io.Reader {
+ panic("unimplemented")
+}
+
+// newExtentFile is the extent file constructor. It reads the entire extent
+// tree into memory.
+//
+// Preconditions: Must hold the mutex of the filesystem containing dev.
+// TODO(b/134676337): Build extent tree on demand to reduce memory usage.
+func newExtentFile(dev io.ReadSeeker, blkSize uint64, regFile regularFile) (*extentFile, error) {
+ file := &extentFile{regFile: regFile}
+ file.regFile.impl = file
+ err := file.buildExtTree(dev, blkSize)
+ if err != nil {
+ return nil, err
+ }
+ return file, nil
+}
+
+// buildExtTree builds the extent tree by reading it from disk by doing
+// running a simple DFS. It first reads the root node from the inode struct in
+// memory. Then it recursively builds the rest of the tree by reading it off
+// disk.
+//
+// Preconditions:
+// - Must hold the mutex of the filesystem containing dev.
+// - Inode flag InExtents must be set.
+func (f *extentFile) buildExtTree(dev io.ReadSeeker, blkSize uint64) error {
+ rootNodeData := f.regFile.inode.diskInode.Data()
+
+ binary.Unmarshal(rootNodeData[:disklayout.ExtentStructsSize], binary.LittleEndian, &f.root.Header)
+
+ // Root node can not have more than 4 entries: 60 bytes = 1 header + 4 entries.
+ if f.root.Header.NumEntries > 4 {
+ // read(2) specifies that EINVAL should be returned if the file is unsuitable
+ // for reading.
+ return syserror.EINVAL
+ }
+
+ f.root.Entries = make([]disklayout.ExtentEntryPair, f.root.Header.NumEntries)
+ for i, off := uint16(0), disklayout.ExtentStructsSize; i < f.root.Header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
+ var curEntry disklayout.ExtentEntry
+ if f.root.Header.Height == 0 {
+ // Leaf node.
+ curEntry = &disklayout.Extent{}
+ } else {
+ // Internal node.
+ curEntry = &disklayout.ExtentIdx{}
+ }
+ binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentStructsSize], binary.LittleEndian, curEntry)
+ f.root.Entries[i].Entry = curEntry
+ }
+
+ // If this node is internal, perform DFS.
+ if f.root.Header.Height > 0 {
+ for i := uint16(0); i < f.root.Header.NumEntries; i++ {
+ var err error
+ if f.root.Entries[i].Node, err = buildExtTreeFromDisk(dev, f.root.Entries[i].Entry, blkSize); err != nil {
+ return err
+ }
+ }
+ }
+
+ return nil
+}
+
+// buildExtTreeFromDisk reads the extent tree nodes from disk and recursively
+// builds the tree. Performs a simple DFS. It returns the ExtentNode pointed to
+// by the ExtentEntry.
+//
+// Preconditions: Must hold the mutex of the filesystem containing dev.
+func buildExtTreeFromDisk(dev io.ReadSeeker, entry disklayout.ExtentEntry, blkSize uint64) (*disklayout.ExtentNode, error) {
+ var header disklayout.ExtentHeader
+ off := entry.PhysicalBlock() * blkSize
+ err := readFromDisk(dev, int64(off), &header)
+ if err != nil {
+ return nil, err
+ }
+
+ entries := make([]disklayout.ExtentEntryPair, header.NumEntries)
+ for i, off := uint16(0), off+disklayout.ExtentStructsSize; i < header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
+ var curEntry disklayout.ExtentEntry
+ if header.Height == 0 {
+ // Leaf node.
+ curEntry = &disklayout.Extent{}
+ } else {
+ // Internal node.
+ curEntry = &disklayout.ExtentIdx{}
+ }
+
+ err := readFromDisk(dev, int64(off), curEntry)
+ if err != nil {
+ return nil, err
+ }
+ entries[i].Entry = curEntry
+ }
+
+ // If this node is internal, perform DFS.
+ if header.Height > 0 {
+ for i := uint16(0); i < header.NumEntries; i++ {
+ var err error
+ entries[i].Node, err = buildExtTreeFromDisk(dev, entries[i].Entry, blkSize)
+ if err != nil {
+ return nil, err
+ }
+ }
+ }
+
+ return &disklayout.ExtentNode{header, entries}, nil
+}
diff --git a/pkg/sentry/fs/ext/extent_test.go b/pkg/sentry/fs/ext/extent_test.go
index b3f342c8e..01251d0a7 100644
--- a/pkg/sentry/fs/ext/extent_test.go
+++ b/pkg/sentry/fs/ext/extent_test.go
@@ -47,7 +47,13 @@ import (
func TestExtentTree(t *testing.T) {
blkSize := uint64(64) // No block has more than 1 header + 4 entries.
mockDisk := make([]byte, blkSize*10)
- mockInode := &inode{diskInode: &disklayout.InodeNew{}}
+ mockExtentFile := extentFile{
+ regFile: regularFile{
+ inode: inode{
+ diskInode: &disklayout.InodeNew{},
+ },
+ },
+ }
node3 := &disklayout.ExtentNode{
Header: disklayout.ExtentHeader{
@@ -138,15 +144,15 @@ func TestExtentTree(t *testing.T) {
},
}
- writeTree(mockInode, mockDisk, node0, blkSize)
+ writeTree(&mockExtentFile.regFile.inode, mockDisk, node0, blkSize)
r := bytes.NewReader(mockDisk)
- if err := mockInode.buildExtTree(r, blkSize); err != nil {
+ if err := mockExtentFile.buildExtTree(r, blkSize); err != nil {
t.Fatalf("inode.buildExtTree failed: %v", err)
}
opt := cmpopts.IgnoreUnexported(disklayout.ExtentIdx{}, disklayout.ExtentHeader{})
- if diff := cmp.Diff(mockInode.root, node0, opt); diff != "" {
+ if diff := cmp.Diff(&mockExtentFile.root, node0, opt); diff != "" {
t.Errorf("extent tree mismatch (-want +got):\n%s", diff)
}
}
diff --git a/pkg/sentry/fs/ext/filesystem.go b/pkg/sentry/fs/ext/filesystem.go
index 7150e75a5..32ca11026 100644
--- a/pkg/sentry/fs/ext/filesystem.go
+++ b/pkg/sentry/fs/ext/filesystem.go
@@ -70,12 +70,12 @@ var _ vfs.FilesystemImpl = (*filesystem)(nil)
// It creates a new one with the given inode number if one does not exist.
//
// Preconditions: must be holding fs.mu.
-func (fs *filesystem) getOrCreateInode(inodeNum uint32) (*inode, error) {
+func (fs *filesystem) getOrCreateInode(ctx context.Context, inodeNum uint32) (*inode, error) {
if in, ok := fs.inodeCache[inodeNum]; ok {
return in, nil
}
- in, err := newInode(fs.dev, fs.sb, fs.bgs, inodeNum)
+ in, err := newInode(ctx, fs.dev, fs.sb, fs.bgs, inodeNum)
if err != nil {
return nil, err
}
diff --git a/pkg/sentry/fs/ext/inline_file.go b/pkg/sentry/fs/ext/inline_file.go
new file mode 100644
index 000000000..dd93ee2e1
--- /dev/null
+++ b/pkg/sentry/fs/ext/inline_file.go
@@ -0,0 +1,65 @@
+// 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 (
+ "io"
+)
+
+// inlineFile is a type of regular file. All the data here is stored in the
+// inode.Data() array.
+type inlineFile struct {
+ regFile regularFile
+}
+
+// Compiles only if inlineFile implements fileReader.
+var _ fileReader = (*inlineFile)(nil)
+
+// getFileReader implements fileReader.getFileReader.
+func (f *inlineFile) getFileReader(_ io.ReadSeeker, _ uint64, offset uint64) io.Reader {
+ diskInode := f.regFile.inode.diskInode
+ return &inlineReader{offset: offset, data: diskInode.Data()[:diskInode.Size()]}
+}
+
+// newInlineFile is the inlineFile constructor.
+func newInlineFile(regFile regularFile) *inlineFile {
+ file := &inlineFile{regFile: regFile}
+ file.regFile.impl = file
+ return file
+}
+
+// inlineReader implements io.Reader which can read the underlying data.
+type inlineReader struct {
+ offset uint64
+ data []byte
+}
+
+// Compiles only if inlineReader implements io.Reader.
+var _ io.Reader = (*inlineReader)(nil)
+
+// Read implements io.Reader.Read.
+func (r *inlineReader) Read(dst []byte) (int, error) {
+ if len(dst) == 0 {
+ return 0, nil
+ }
+
+ if int(r.offset) >= len(r.data) {
+ return 0, io.EOF
+ }
+
+ n := copy(dst, r.data[r.offset:])
+ r.offset += uint64(n)
+ return n, nil
+}
diff --git a/pkg/sentry/fs/ext/inode.go b/pkg/sentry/fs/ext/inode.go
index df1ea0bda..7d2a445fb 100644
--- a/pkg/sentry/fs/ext/inode.go
+++ b/pkg/sentry/fs/ext/inode.go
@@ -18,12 +18,26 @@ import (
"io"
"sync/atomic"
- "gvisor.dev/gvisor/pkg/binary"
+ "gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/fs/ext/disklayout"
"gvisor.dev/gvisor/pkg/syserror"
)
// inode represents an ext inode.
+//
+// inode uses the same inheritance pattern that pkg/sentry/vfs structures use.
+// This has been done to increase memory locality.
+//
+// Implementations:
+// inode --
+// |-- pipe
+// |-- dir
+// |-- symlink
+// |-- regular--
+// |-- extent file
+// |-- block map file
+// |-- inline file
type inode struct {
// refs is a reference count. refs is accessed using atomic memory operations.
refs int64
@@ -35,9 +49,9 @@ type inode struct {
// diskInode gives us access to the inode struct on disk. Immutable.
diskInode disklayout.Inode
- // root is the root extent node. This lives in the 60 byte diskInode.Blocks().
- // Immutable. Nil if the inode does not use extents.
- root *disklayout.ExtentNode
+ // This is immutable. The first field of the implementations must have inode
+ // as the first field to ensure temporality.
+ impl interface{}
}
// incRef increments the inode ref count.
@@ -74,17 +88,17 @@ func (in *inode) decRef(fs *filesystem) {
// inodes based on the absolute inode number on disk.
//
// Preconditions: Must hold the mutex of the filesystem containing dev.
-func newInode(dev io.ReadSeeker, sb disklayout.SuperBlock, bgs []disklayout.BlockGroup, inodeNum uint32) (*inode, error) {
+func newInode(ctx context.Context, dev io.ReadSeeker, sb disklayout.SuperBlock, bgs []disklayout.BlockGroup, inodeNum uint32) (*inode, error) {
if inodeNum == 0 {
panic("inode number 0 on ext filesystems is not possible")
}
- in := &inode{refs: 1, inodeNum: inodeNum}
inodeRecordSize := sb.InodeSize()
+ var diskInode disklayout.Inode
if inodeRecordSize == disklayout.OldInodeSize {
- in.diskInode = &disklayout.InodeOld{}
+ diskInode = &disklayout.InodeOld{}
} else {
- in.diskInode = &disklayout.InodeNew{}
+ diskInode = &disklayout.InodeNew{}
}
// Calculate where the inode is actually placed.
@@ -93,16 +107,38 @@ func newInode(dev io.ReadSeeker, sb disklayout.SuperBlock, bgs []disklayout.Bloc
inodeTableOff := bgs[getBGNum(inodeNum, inodesPerGrp)].InodeTable() * blkSize
inodeOff := inodeTableOff + uint64(uint32(inodeRecordSize)*getBGOff(inodeNum, inodesPerGrp))
- // Read it from disk and figure out which type of inode this is.
- if err := readFromDisk(dev, int64(inodeOff), in.diskInode); err != nil {
+ if err := readFromDisk(dev, int64(inodeOff), diskInode); err != nil {
return nil, err
}
- if in.diskInode.Flags().Extents {
- in.buildExtTree(dev, blkSize)
+ // Build the inode based on its type.
+ inode := inode{
+ refs: 1,
+ inodeNum: inodeNum,
+ diskInode: diskInode,
}
- return in, nil
+ switch diskInode.Mode().FileType() {
+ case linux.ModeSymlink:
+ f, err := newSymlink(dev, blkSize, inode)
+ if err != nil {
+ return nil, err
+ }
+ return &f.inode, nil
+ case linux.ModeRegular:
+ f, err := newRegularFile(dev, blkSize, inode)
+ if err != nil {
+ return nil, err
+ }
+ return &f.inode, nil
+ case linux.ModeDirectory:
+ return &newDirectroy(inode).inode, nil
+ case linux.ModeNamedPipe:
+ return &newNamedPipe(ctx, inode).inode, nil
+ default:
+ // TODO(b/134676337): Return appropriate errors for sockets and devices.
+ return nil, syserror.EINVAL
+ }
}
// getBGNum returns the block group number that a given inode belongs to.
@@ -115,95 +151,3 @@ func getBGNum(inodeNum uint32, inodesPerGrp uint32) uint32 {
func getBGOff(inodeNum uint32, inodesPerGrp uint32) uint32 {
return (inodeNum - 1) % inodesPerGrp
}
-
-// buildExtTree builds the extent tree by reading it from disk by doing
-// running a simple DFS. It first reads the root node from the inode struct in
-// memory. Then it recursively builds the rest of the tree by reading it off
-// disk.
-//
-// Preconditions:
-// - Must hold the mutex of the filesystem containing dev.
-// - Inode flag InExtents must be set.
-func (in *inode) buildExtTree(dev io.ReadSeeker, blkSize uint64) error {
- rootNodeData := in.diskInode.Data()
-
- var rootHeader disklayout.ExtentHeader
- binary.Unmarshal(rootNodeData[:disklayout.ExtentStructsSize], binary.LittleEndian, &rootHeader)
-
- // Root node can not have more than 4 entries: 60 bytes = 1 header + 4 entries.
- if rootHeader.NumEntries > 4 {
- // read(2) specifies that EINVAL should be returned if the file is unsuitable
- // for reading.
- return syserror.EINVAL
- }
-
- rootEntries := make([]disklayout.ExtentEntryPair, rootHeader.NumEntries)
- for i, off := uint16(0), disklayout.ExtentStructsSize; i < rootHeader.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
- var curEntry disklayout.ExtentEntry
- if rootHeader.Height == 0 {
- // Leaf node.
- curEntry = &disklayout.Extent{}
- } else {
- // Internal node.
- curEntry = &disklayout.ExtentIdx{}
- }
- binary.Unmarshal(rootNodeData[off:off+disklayout.ExtentStructsSize], binary.LittleEndian, curEntry)
- rootEntries[i].Entry = curEntry
- }
-
- // If this node is internal, perform DFS.
- if rootHeader.Height > 0 {
- for i := uint16(0); i < rootHeader.NumEntries; i++ {
- var err error
- if rootEntries[i].Node, err = buildExtTreeFromDisk(dev, rootEntries[i].Entry, blkSize); err != nil {
- return err
- }
- }
- }
-
- in.root = &disklayout.ExtentNode{rootHeader, rootEntries}
- return nil
-}
-
-// buildExtTreeFromDisk reads the extent tree nodes from disk and recursively
-// builds the tree. Performs a simple DFS. It returns the ExtentNode pointed to
-// by the ExtentEntry.
-//
-// Preconditions: Must hold the mutex of the filesystem containing dev.
-func buildExtTreeFromDisk(dev io.ReadSeeker, entry disklayout.ExtentEntry, blkSize uint64) (*disklayout.ExtentNode, error) {
- var header disklayout.ExtentHeader
- off := entry.PhysicalBlock() * blkSize
- if err := readFromDisk(dev, int64(off), &header); err != nil {
- return nil, err
- }
-
- entries := make([]disklayout.ExtentEntryPair, header.NumEntries)
- for i, off := uint16(0), off+disklayout.ExtentStructsSize; i < header.NumEntries; i, off = i+1, off+disklayout.ExtentStructsSize {
- var curEntry disklayout.ExtentEntry
- if header.Height == 0 {
- // Leaf node.
- curEntry = &disklayout.Extent{}
- } else {
- // Internal node.
- curEntry = &disklayout.ExtentIdx{}
- }
-
- if err := readFromDisk(dev, int64(off), curEntry); err != nil {
- return nil, err
- }
- entries[i].Entry = curEntry
- }
-
- // If this node is internal, perform DFS.
- if header.Height > 0 {
- for i := uint16(0); i < header.NumEntries; i++ {
- var err error
- entries[i].Node, err = buildExtTreeFromDisk(dev, entries[i].Entry, blkSize)
- if err != nil {
- return nil, err
- }
- }
- }
-
- return &disklayout.ExtentNode{header, entries}, nil
-}
diff --git a/pkg/sentry/fs/ext/named_pipe.go b/pkg/sentry/fs/ext/named_pipe.go
new file mode 100644
index 000000000..0f3af1b53
--- /dev/null
+++ b/pkg/sentry/fs/ext/named_pipe.go
@@ -0,0 +1,40 @@
+// 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 (
+ "gvisor.dev/gvisor/pkg/sentry/context"
+ "gvisor.dev/gvisor/pkg/sentry/fs"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/pipe"
+ "gvisor.dev/gvisor/pkg/sentry/usermem"
+)
+
+// namedPipe represents a named pipe inode. It is currently just a wrapper
+// around pkg/sentry/kernel/pipe.
+type namedPipe struct {
+ inode inode
+
+ p *pipe.Pipe
+ inodeOps fs.InodeOperations
+}
+
+// newNamedPipe is the namedPipe constructor.
+func newNamedPipe(ctx context.Context, inode inode) *namedPipe {
+ file := &namedPipe{inode: inode}
+ file.inode.impl = file
+ file.p = pipe.NewPipe(ctx, true /* isNamed */, pipe.DefaultPipeSize, usermem.PageSize)
+ file.inodeOps = pipe.NewInodeOperations(ctx, fs.FilePermsFromMode(file.inode.diskInode.Mode()), file.p)
+ return file
+}
diff --git a/pkg/sentry/fs/ext/regular_file.go b/pkg/sentry/fs/ext/regular_file.go
new file mode 100644
index 000000000..9bf39acfe
--- /dev/null
+++ b/pkg/sentry/fs/ext/regular_file.go
@@ -0,0 +1,90 @@
+// 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 (
+ "io"
+)
+
+// fileReader is used to abstact away the complexity of how the file data is
+// stored under the hood. Provides a method to get a file reader which can be
+// used to read file data without worrying about how it is organized on disk.
+type fileReader interface {
+
+ // getFileReader returns a Reader implementation which can be used to read a
+ // file. It abstracts away the complexity of how the file is actually
+ // organized on disk. The reader is initialized with the passed offset.
+ //
+ // This reader is not meant to be retained across Read operations as it needs
+ // to be reinitialized with the correct offset for every Read.
+ //
+ // Precondition: Must hold the mutex of the filesystem containing dev while
+ // using the Reader.
+ getFileReader(dev io.ReadSeeker, blkSize uint64, offset uint64) io.Reader
+}
+
+// regularFile represents a regular file's inode. This too follows the
+// inheritance pattern prevelant in the vfs layer described in
+// pkg/sentry/vfs/README.md.
+type regularFile struct {
+ inode inode
+
+ // This is immutable. The first field of fileReader implementations must be
+ // regularFile to ensure temporality.
+ impl fileReader
+}
+
+// newRegularFile is the regularFile constructor. It figures out what kind of
+// file this is and initializes the fileReader.
+//
+// Preconditions: Must hold the mutex of the filesystem containing dev.
+func newRegularFile(dev io.ReadSeeker, blkSize uint64, inode inode) (*regularFile, error) {
+ regFile := regularFile{
+ inode: inode,
+ }
+
+ inodeFlags := inode.diskInode.Flags()
+
+ if inodeFlags.Extents {
+ file, err := newExtentFile(dev, blkSize, regFile)
+ if err != nil {
+ return nil, err
+ }
+
+ file.regFile.inode.impl = &file.regFile
+ return &file.regFile, nil
+ }
+
+ if inodeFlags.Inline {
+ if inode.diskInode.Size() > 60 {
+ panic("ext fs: inline file larger than 60 bytes")
+ }
+
+ file := newInlineFile(regFile)
+ file.regFile.inode.impl = &file.regFile
+ return &file.regFile, nil
+ }
+
+ file, err := newBlockMapFile(blkSize, regFile)
+ if err != nil {
+ return nil, err
+ }
+ file.regFile.inode.impl = &file.regFile
+ return &file.regFile, nil
+}
+
+func (f *regularFile) blksUsed(blkSize uint64) uint64 {
+ return (f.inode.diskInode.Size() + blkSize - 1) / blkSize
+}
diff --git a/pkg/sentry/fs/ext/symlink.go b/pkg/sentry/fs/ext/symlink.go
new file mode 100644
index 000000000..0ed67c0e4
--- /dev/null
+++ b/pkg/sentry/fs/ext/symlink.go
@@ -0,0 +1,59 @@
+// 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 (
+ "io"
+
+ "gvisor.dev/gvisor/pkg/syserror"
+)
+
+// symlink represents a symlink inode.
+type symlink struct {
+ inode inode
+ target string // immutable
+}
+
+// newSymlink is the symlink constructor. It reads out the symlink target from
+// the inode (however it might have been stored).
+//
+// Preconditions: Must hold the mutex of the filesystem containing dev.
+func newSymlink(dev io.ReadSeeker, blkSize uint64, inode inode) (*symlink, error) {
+ var file *symlink
+ var link []byte
+
+ // If the symlink target is lesser than 60 bytes, its stores in inode.Data().
+ // Otherwise either extents or block maps will be used to store the link.
+ size := inode.diskInode.Size()
+ if size < 60 {
+ link = inode.diskInode.Data()[:size]
+ } else {
+ // Create a regular file out of this inode and read out the target.
+ regFile, err := newRegularFile(dev, blkSize, inode)
+ if err != nil {
+ return nil, err
+ }
+
+ link = make([]byte, size)
+ reader := regFile.impl.getFileReader(dev, blkSize, 0)
+ if _, err := io.ReadFull(reader, link); err != nil {
+ return nil, syserror.EIO
+ }
+ }
+
+ file = &symlink{inode: inode, target: string(link)}
+ file.inode.impl = file
+ return file, nil
+}
diff --git a/pkg/sentry/fs/ext/utils.go b/pkg/sentry/fs/ext/utils.go
index 3472c5fa8..8790c7778 100644
--- a/pkg/sentry/fs/ext/utils.go
+++ b/pkg/sentry/fs/ext/utils.go
@@ -76,12 +76,7 @@ func blockGroupsCount(sb disklayout.SuperBlock) uint64 {
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
+ return (blocksCount + blocksPerGroup - 1) / blocksPerGroup
}
// readBlockGroups reads the block group descriptor table from block group 0 in
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 12:41:10 +0000