1 files changed, 0 insertions, 393 deletions
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
deleted file mode 100644
index 1d4889c89..000000000
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ /dev/null
@@ -1,393 +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 tmpfs provides a filesystem implementation that behaves like tmpfs:
-// the Dentry tree is the sole source of truth for the state of the filesystem.
-//
-// Lock order:
-//
-// filesystem.mu
-//   regularFileFD.offMu
-//     regularFile.mu
-//   inode.mu
-package tmpfs
-
-import (
-	"fmt"
-	"math"
-	"sync/atomic"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/sentry/context"
-	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
-	"gvisor.dev/gvisor/pkg/sentry/kernel/time"
-	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-// FilesystemType implements vfs.FilesystemType.
-type FilesystemType struct{}
-
-// filesystem implements vfs.FilesystemImpl.
-type filesystem struct {
-	vfsfs vfs.Filesystem
-
-	// memFile is used to allocate pages to for regular files.
-	memFile *pgalloc.MemoryFile
-
-	// clock is a realtime clock used to set timestamps in file operations.
-	clock time.Clock
-
-	// mu serializes changes to the Dentry tree.
-	mu sync.RWMutex
-
-	nextInoMinusOne uint64 // accessed using atomic memory operations
-}
-
-// GetFilesystem implements vfs.FilesystemType.GetFilesystem.
-func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, source string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
-	memFileProvider := pgalloc.MemoryFileProviderFromContext(ctx)
-	if memFileProvider == nil {
-		panic("MemoryFileProviderFromContext returned nil")
-	}
-	clock := time.RealtimeClockFromContext(ctx)
-	fs := filesystem{
-		memFile: memFileProvider.MemoryFile(),
-		clock:   clock,
-	}
-	fs.vfsfs.Init(vfsObj, &fs)
-	root := fs.newDentry(fs.newDirectory(creds, 01777))
-	return &fs.vfsfs, &root.vfsd, nil
-}
-
-// Release implements vfs.FilesystemImpl.Release.
-func (fs *filesystem) Release() {
-}
-
-// dentry implements vfs.DentryImpl.
-type dentry struct {
-	vfsd vfs.Dentry
-
-	// inode is the inode represented by this dentry. Multiple Dentries may
-	// share a single non-directory inode (with hard links). inode is
-	// immutable.
-	inode *inode
-
-	// tmpfs doesn't count references on dentries; because the dentry tree is
-	// the sole source of truth, it is by definition always consistent with the
-	// state of the filesystem. However, it does count references on inodes,
-	// because inode resources are released when all references are dropped.
-	// (tmpfs doesn't really have resources to release, but we implement
-	// reference counting because tmpfs regular files will.)
-
-	// dentryEntry (ugh) links dentries into their parent directory.childList.
-	dentryEntry
-}
-
-func (fs *filesystem) newDentry(inode *inode) *dentry {
-	d := &dentry{
-		inode: inode,
-	}
-	d.vfsd.Init(d)
-	return d
-}
-
-// IncRef implements vfs.DentryImpl.IncRef.
-func (d *dentry) IncRef() {
-	d.inode.incRef()
-}
-
-// TryIncRef implements vfs.DentryImpl.TryIncRef.
-func (d *dentry) TryIncRef() bool {
-	return d.inode.tryIncRef()
-}
-
-// DecRef implements vfs.DentryImpl.DecRef.
-func (d *dentry) DecRef() {
-	d.inode.decRef()
-}
-
-// inode represents a filesystem object.
-type inode struct {
-	// clock is a realtime clock used to set timestamps in file operations.
-	clock time.Clock
-
-	// refs is a reference count. refs is accessed using atomic memory
-	// operations.
-	//
-	// A reference is held on all inodes that are reachable in the filesystem
-	// tree. For non-directories (which may have multiple hard links), this
-	// means that a reference is dropped when nlink reaches 0. For directories,
-	// nlink never reaches 0 due to the "." entry; instead,
-	// filesystem.RmdirAt() drops the reference.
-	refs int64
-
-	// Inode metadata. Writing multiple fields atomically requires holding
-	// mu, othewise atomic operations can be used.
-	mu    sync.Mutex
-	mode  uint32 // excluding file type bits, which are based on impl
-	nlink uint32 // protected by filesystem.mu instead of inode.mu
-	uid   uint32 // auth.KUID, but stored as raw uint32 for sync/atomic
-	gid   uint32 // auth.KGID, but ...
-	ino   uint64 // immutable
-
-	// Linux's tmpfs has no concept of btime.
-	atime int64 // nanoseconds
-	ctime int64 // nanoseconds
-	mtime int64 // nanoseconds
-
-	impl interface{} // immutable
-}
-
-const maxLinks = math.MaxUint32
-
-func (i *inode) init(impl interface{}, fs *filesystem, creds *auth.Credentials, mode linux.FileMode) {
-	i.clock = fs.clock
-	i.refs = 1
-	i.mode = uint32(mode)
-	i.uid = uint32(creds.EffectiveKUID)
-	i.gid = uint32(creds.EffectiveKGID)
-	i.ino = atomic.AddUint64(&fs.nextInoMinusOne, 1)
-	// Tmpfs creation sets atime, ctime, and mtime to current time.
-	now := i.clock.Now().Nanoseconds()
-	i.atime = now
-	i.ctime = now
-	i.mtime = now
-	// i.nlink initialized by caller
-	i.impl = impl
-}
-
-// incLinksLocked increments i's link count.
-//
-// Preconditions: filesystem.mu must be locked for writing. i.nlink != 0.
-// i.nlink < maxLinks.
-func (i *inode) incLinksLocked() {
-	if i.nlink == 0 {
-		panic("tmpfs.inode.incLinksLocked() called with no existing links")
-	}
-	if i.nlink == maxLinks {
-		panic("memfs.inode.incLinksLocked() called with maximum link count")
-	}
-	atomic.AddUint32(&i.nlink, 1)
-}
-
-// decLinksLocked decrements i's link count.
-//
-// Preconditions: filesystem.mu must be locked for writing. i.nlink != 0.
-func (i *inode) decLinksLocked() {
-	if i.nlink == 0 {
-		panic("tmpfs.inode.decLinksLocked() called with no existing links")
-	}
-	atomic.AddUint32(&i.nlink, ^uint32(0))
-}
-
-func (i *inode) incRef() {
-	if atomic.AddInt64(&i.refs, 1) <= 1 {
-		panic("tmpfs.inode.incRef() called without holding a reference")
-	}
-}
-
-func (i *inode) tryIncRef() bool {
-	for {
-		refs := atomic.LoadInt64(&i.refs)
-		if refs == 0 {
-			return false
-		}
-		if atomic.CompareAndSwapInt64(&i.refs, refs, refs+1) {
-			return true
-		}
-	}
-}
-
-func (i *inode) decRef() {
-	if refs := atomic.AddInt64(&i.refs, -1); refs == 0 {
-		// This is unnecessary; it's mostly to simulate what tmpfs would do.
-		if regFile, ok := i.impl.(*regularFile); ok {
-			regFile.mu.Lock()
-			regFile.data.DropAll(regFile.memFile)
-			atomic.StoreUint64(&regFile.size, 0)
-			regFile.mu.Unlock()
-		}
-	} else if refs < 0 {
-		panic("tmpfs.inode.decRef() called without holding a reference")
-	}
-}
-
-func (i *inode) checkPermissions(creds *auth.Credentials, ats vfs.AccessTypes, isDir bool) error {
-	return vfs.GenericCheckPermissions(creds, ats, isDir, uint16(atomic.LoadUint32(&i.mode)), auth.KUID(atomic.LoadUint32(&i.uid)), auth.KGID(atomic.LoadUint32(&i.gid)))
-}
-
-// Go won't inline this function, and returning linux.Statx (which is quite
-// big) means spending a lot of time in runtime.duffcopy(), so instead it's an
-// output parameter.
-//
-// Note that Linux does not guarantee to return consistent data (in the case of
-// a concurrent modification), so we do not require holding inode.mu.
-func (i *inode) statTo(stat *linux.Statx) {
-	stat.Mask = linux.STATX_TYPE | linux.STATX_MODE | linux.STATX_NLINK |
-		linux.STATX_UID | linux.STATX_GID | linux.STATX_INO | linux.STATX_ATIME |
-		linux.STATX_BTIME | linux.STATX_CTIME | linux.STATX_MTIME
-	stat.Blksize = 1 // usermem.PageSize in tmpfs
-	stat.Nlink = atomic.LoadUint32(&i.nlink)
-	stat.UID = atomic.LoadUint32(&i.uid)
-	stat.GID = atomic.LoadUint32(&i.gid)
-	stat.Mode = uint16(atomic.LoadUint32(&i.mode))
-	stat.Ino = i.ino
-	// Linux's tmpfs has no concept of btime, so zero-value is returned.
-	stat.Atime = linux.NsecToStatxTimestamp(i.atime)
-	stat.Ctime = linux.NsecToStatxTimestamp(i.ctime)
-	stat.Mtime = linux.NsecToStatxTimestamp(i.mtime)
-	// TODO(gvisor.dev/issues/1197): Device number.
-	switch impl := i.impl.(type) {
-	case *regularFile:
-		stat.Mode |= linux.S_IFREG
-		stat.Mask |= linux.STATX_SIZE | linux.STATX_BLOCKS
-		stat.Size = uint64(atomic.LoadUint64(&impl.size))
-		// In tmpfs, this will be FileRangeSet.Span() / 512 (but also cached in
-		// a uint64 accessed using atomic memory operations to avoid taking
-		// locks).
-		stat.Blocks = allocatedBlocksForSize(stat.Size)
-	case *directory:
-		stat.Mode |= linux.S_IFDIR
-	case *symlink:
-		stat.Mode |= linux.S_IFLNK
-		stat.Mask |= linux.STATX_SIZE | linux.STATX_BLOCKS
-		stat.Size = uint64(len(impl.target))
-		stat.Blocks = allocatedBlocksForSize(stat.Size)
-	case *namedPipe:
-		stat.Mode |= linux.S_IFIFO
-	default:
-		panic(fmt.Sprintf("unknown inode type: %T", i.impl))
-	}
-}
-
-func (i *inode) setStat(stat linux.Statx) error {
-	if stat.Mask == 0 {
-		return nil
-	}
-	i.mu.Lock()
-	var (
-		needsMtimeBump bool
-		needsCtimeBump bool
-	)
-	mask := stat.Mask
-	if mask&linux.STATX_MODE != 0 {
-		atomic.StoreUint32(&i.mode, uint32(stat.Mode))
-		needsCtimeBump = true
-	}
-	if mask&linux.STATX_UID != 0 {
-		atomic.StoreUint32(&i.uid, stat.UID)
-		needsCtimeBump = true
-	}
-	if mask&linux.STATX_GID != 0 {
-		atomic.StoreUint32(&i.gid, stat.GID)
-		needsCtimeBump = true
-	}
-	if mask&linux.STATX_SIZE != 0 {
-		switch impl := i.impl.(type) {
-		case *regularFile:
-			updated, err := impl.truncate(stat.Size)
-			if err != nil {
-				return err
-			}
-			if updated {
-				needsMtimeBump = true
-				needsCtimeBump = true
-			}
-		case *directory:
-			return syserror.EISDIR
-		case *symlink:
-			return syserror.EINVAL
-		case *namedPipe:
-			// Nothing.
-		default:
-			panic(fmt.Sprintf("unknown inode type: %T", i.impl))
-		}
-	}
-	if mask&linux.STATX_ATIME != 0 {
-		atomic.StoreInt64(&i.atime, stat.Atime.ToNsecCapped())
-		needsCtimeBump = true
-	}
-	if mask&linux.STATX_MTIME != 0 {
-		atomic.StoreInt64(&i.mtime, stat.Mtime.ToNsecCapped())
-		needsCtimeBump = true
-		// Ignore the mtime bump, since we just set it ourselves.
-		needsMtimeBump = false
-	}
-	if mask&linux.STATX_CTIME != 0 {
-		atomic.StoreInt64(&i.ctime, stat.Ctime.ToNsecCapped())
-		// Ignore the ctime bump, since we just set it ourselves.
-		needsCtimeBump = false
-	}
-	now := i.clock.Now().Nanoseconds()
-	if needsMtimeBump {
-		atomic.StoreInt64(&i.mtime, now)
-	}
-	if needsCtimeBump {
-		atomic.StoreInt64(&i.ctime, now)
-	}
-	i.mu.Unlock()
-	return nil
-}
-
-// allocatedBlocksForSize returns the number of 512B blocks needed to
-// accommodate the given size in bytes, as appropriate for struct
-// stat::st_blocks and struct statx::stx_blocks. (Note that this 512B block
-// size is independent of the "preferred block size for I/O", struct
-// stat::st_blksize and struct statx::stx_blksize.)
-func allocatedBlocksForSize(size uint64) uint64 {
-	return (size + 511) / 512
-}
-
-func (i *inode) direntType() uint8 {
-	switch i.impl.(type) {
-	case *regularFile:
-		return linux.DT_REG
-	case *directory:
-		return linux.DT_DIR
-	case *symlink:
-		return linux.DT_LNK
-	default:
-		panic(fmt.Sprintf("unknown inode type: %T", i.impl))
-	}
-}
-
-// fileDescription is embedded by tmpfs implementations of
-// vfs.FileDescriptionImpl.
-type fileDescription struct {
-	vfsfd vfs.FileDescription
-	vfs.FileDescriptionDefaultImpl
-}
-
-func (fd *fileDescription) filesystem() *filesystem {
-	return fd.vfsfd.Mount().Filesystem().Impl().(*filesystem)
-}
-
-func (fd *fileDescription) inode() *inode {
-	return fd.vfsfd.Dentry().Impl().(*dentry).inode
-}
-
-// Stat implements vfs.FileDescriptionImpl.Stat.
-func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
-	var stat linux.Statx
-	fd.inode().statTo(&stat)
-	return stat, nil
-}
-
-// SetStat implements vfs.FileDescriptionImpl.SetStat.
-func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
-	return fd.inode().setStat(opts.Stat)
-}