1 files changed, 0 insertions, 380 deletions
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
deleted file mode 100644
index e9e6faf67..000000000
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ /dev/null
@@ -1,380 +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
-
-import (
-	"io"
-	"math"
-	"sync/atomic"
-
-	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/context"
-	"gvisor.dev/gvisor/pkg/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
-	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
-	"gvisor.dev/gvisor/pkg/sentry/memmap"
-	"gvisor.dev/gvisor/pkg/sentry/pgalloc"
-	"gvisor.dev/gvisor/pkg/sentry/usage"
-	"gvisor.dev/gvisor/pkg/sentry/vfs"
-	"gvisor.dev/gvisor/pkg/sync"
-	"gvisor.dev/gvisor/pkg/syserror"
-	"gvisor.dev/gvisor/pkg/usermem"
-)
-
-type regularFile struct {
-	inode inode
-
-	// memFile is a platform.File used to allocate pages to this regularFile.
-	memFile *pgalloc.MemoryFile
-
-	// mu protects the fields below.
-	mu sync.RWMutex
-
-	// data maps offsets into the file to offsets into memFile that store
-	// the file's data.
-	data fsutil.FileRangeSet
-
-	// size is the size of data, but accessed using atomic memory
-	// operations to avoid locking in inode.stat().
-	size uint64
-
-	// seals represents file seals on this inode.
-	seals uint32
-}
-
-func (fs *filesystem) newRegularFile(creds *auth.Credentials, mode linux.FileMode) *inode {
-	file := &regularFile{
-		memFile: fs.memFile,
-	}
-	file.inode.init(file, fs, creds, mode)
-	file.inode.nlink = 1 // from parent directory
-	return &file.inode
-}
-
-// truncate grows or shrinks the file to the given size. It returns true if the
-// file size was updated.
-func (rf *regularFile) truncate(size uint64) (bool, error) {
-	rf.mu.Lock()
-	defer rf.mu.Unlock()
-
-	if size == rf.size {
-		// Nothing to do.
-		return false, nil
-	}
-
-	if size > rf.size {
-		// Growing the file.
-		if rf.seals&linux.F_SEAL_GROW != 0 {
-			// Seal does not allow growth.
-			return false, syserror.EPERM
-		}
-		rf.size = size
-		return true, nil
-	}
-
-	// Shrinking the file
-	if rf.seals&linux.F_SEAL_SHRINK != 0 {
-		// Seal does not allow shrink.
-		return false, syserror.EPERM
-	}
-
-	// TODO(gvisor.dev/issues/1197): Invalidate mappings once we have
-	// mappings.
-
-	rf.data.Truncate(size, rf.memFile)
-	rf.size = size
-	return true, nil
-}
-
-type regularFileFD struct {
-	fileDescription
-
-	// off is the file offset. off is accessed using atomic memory operations.
-	// offMu serializes operations that may mutate off.
-	off   int64
-	offMu sync.Mutex
-}
-
-// Release implements vfs.FileDescriptionImpl.Release.
-func (fd *regularFileFD) Release() {
-	// noop
-}
-
-// PRead implements vfs.FileDescriptionImpl.PRead.
-func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
-	if offset < 0 {
-		return 0, syserror.EINVAL
-	}
-	if dst.NumBytes() == 0 {
-		return 0, nil
-	}
-	f := fd.inode().impl.(*regularFile)
-	rw := getRegularFileReadWriter(f, offset)
-	n, err := dst.CopyOutFrom(ctx, rw)
-	putRegularFileReadWriter(rw)
-	return int64(n), err
-}
-
-// Read implements vfs.FileDescriptionImpl.Read.
-func (fd *regularFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
-	fd.offMu.Lock()
-	n, err := fd.PRead(ctx, dst, fd.off, opts)
-	fd.off += n
-	fd.offMu.Unlock()
-	return n, err
-}
-
-// PWrite implements vfs.FileDescriptionImpl.PWrite.
-func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
-	if offset < 0 {
-		return 0, syserror.EINVAL
-	}
-	srclen := src.NumBytes()
-	if srclen == 0 {
-		return 0, nil
-	}
-	f := fd.inode().impl.(*regularFile)
-	end := offset + srclen
-	if end < offset {
-		// Overflow.
-		return 0, syserror.EFBIG
-	}
-	rw := getRegularFileReadWriter(f, offset)
-	n, err := src.CopyInTo(ctx, rw)
-	putRegularFileReadWriter(rw)
-	return n, err
-}
-
-// Write implements vfs.FileDescriptionImpl.Write.
-func (fd *regularFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
-	fd.offMu.Lock()
-	n, err := fd.PWrite(ctx, src, fd.off, opts)
-	fd.off += n
-	fd.offMu.Unlock()
-	return n, err
-}
-
-// Seek implements vfs.FileDescriptionImpl.Seek.
-func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
-	fd.offMu.Lock()
-	defer fd.offMu.Unlock()
-	switch whence {
-	case linux.SEEK_SET:
-		// use offset as specified
-	case linux.SEEK_CUR:
-		offset += fd.off
-	case linux.SEEK_END:
-		offset += int64(atomic.LoadUint64(&fd.inode().impl.(*regularFile).size))
-	default:
-		return 0, syserror.EINVAL
-	}
-	if offset < 0 {
-		return 0, syserror.EINVAL
-	}
-	fd.off = offset
-	return offset, nil
-}
-
-// Sync implements vfs.FileDescriptionImpl.Sync.
-func (fd *regularFileFD) Sync(ctx context.Context) error {
-	return nil
-}
-
-// regularFileReadWriter implements safemem.Reader and Safemem.Writer.
-type regularFileReadWriter struct {
-	file *regularFile
-
-	// Offset into the file to read/write at. Note that this may be
-	// different from the FD offset if PRead/PWrite is used.
-	off uint64
-}
-
-var regularFileReadWriterPool = sync.Pool{
-	New: func() interface{} {
-		return &regularFileReadWriter{}
-	},
-}
-
-func getRegularFileReadWriter(file *regularFile, offset int64) *regularFileReadWriter {
-	rw := regularFileReadWriterPool.Get().(*regularFileReadWriter)
-	rw.file = file
-	rw.off = uint64(offset)
-	return rw
-}
-
-func putRegularFileReadWriter(rw *regularFileReadWriter) {
-	rw.file = nil
-	regularFileReadWriterPool.Put(rw)
-}
-
-// ReadToBlocks implements safemem.Reader.ReadToBlocks.
-func (rw *regularFileReadWriter) ReadToBlocks(dsts safemem.BlockSeq) (uint64, error) {
-	rw.file.mu.RLock()
-
-	// Compute the range to read (limited by file size and overflow-checked).
-	if rw.off >= rw.file.size {
-		rw.file.mu.RUnlock()
-		return 0, io.EOF
-	}
-	end := rw.file.size
-	if rend := rw.off + dsts.NumBytes(); rend > rw.off && rend < end {
-		end = rend
-	}
-
-	var done uint64
-	seg, gap := rw.file.data.Find(uint64(rw.off))
-	for rw.off < end {
-		mr := memmap.MappableRange{uint64(rw.off), uint64(end)}
-		switch {
-		case seg.Ok():
-			// Get internal mappings.
-			ims, err := rw.file.memFile.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), usermem.Read)
-			if err != nil {
-				rw.file.mu.RUnlock()
-				return done, err
-			}
-
-			// Copy from internal mappings.
-			n, err := safemem.CopySeq(dsts, ims)
-			done += n
-			rw.off += uint64(n)
-			dsts = dsts.DropFirst64(n)
-			if err != nil {
-				rw.file.mu.RUnlock()
-				return done, err
-			}
-
-			// Continue.
-			seg, gap = seg.NextNonEmpty()
-
-		case gap.Ok():
-			// Tmpfs holes are zero-filled.
-			gapmr := gap.Range().Intersect(mr)
-			dst := dsts.TakeFirst64(gapmr.Length())
-			n, err := safemem.ZeroSeq(dst)
-			done += n
-			rw.off += uint64(n)
-			dsts = dsts.DropFirst64(n)
-			if err != nil {
-				rw.file.mu.RUnlock()
-				return done, err
-			}
-
-			// Continue.
-			seg, gap = gap.NextSegment(), fsutil.FileRangeGapIterator{}
-		}
-	}
-	rw.file.mu.RUnlock()
-	return done, nil
-}
-
-// WriteFromBlocks implements safemem.Writer.WriteFromBlocks.
-func (rw *regularFileReadWriter) WriteFromBlocks(srcs safemem.BlockSeq) (uint64, error) {
-	rw.file.mu.Lock()
-
-	// Compute the range to write (overflow-checked).
-	end := rw.off + srcs.NumBytes()
-	if end <= rw.off {
-		end = math.MaxInt64
-	}
-
-	// Check if seals prevent either file growth or all writes.
-	switch {
-	case rw.file.seals&linux.F_SEAL_WRITE != 0: // Write sealed
-		rw.file.mu.Unlock()
-		return 0, syserror.EPERM
-	case end > rw.file.size && rw.file.seals&linux.F_SEAL_GROW != 0: // Grow sealed
-		// When growth is sealed, Linux effectively allows writes which would
-		// normally grow the file to partially succeed up to the current EOF,
-		// rounded down to the page boundary before the EOF.
-		//
-		// This happens because writes (and thus the growth check) for tmpfs
-		// files proceed page-by-page on Linux, and the final write to the page
-		// containing EOF fails, resulting in a partial write up to the start of
-		// that page.
-		//
-		// To emulate this behaviour, artifically truncate the write to the
-		// start of the page containing the current EOF.
-		//
-		// See Linux, mm/filemap.c:generic_perform_write() and
-		// mm/shmem.c:shmem_write_begin().
-		if pgstart := uint64(usermem.Addr(rw.file.size).RoundDown()); end > pgstart {
-			end = pgstart
-		}
-		if end <= rw.off {
-			// Truncation would result in no data being written.
-			rw.file.mu.Unlock()
-			return 0, syserror.EPERM
-		}
-	}
-
-	// Page-aligned mr for when we need to allocate memory. RoundUp can't
-	// overflow since end is an int64.
-	pgstartaddr := usermem.Addr(rw.off).RoundDown()
-	pgendaddr, _ := usermem.Addr(end).RoundUp()
-	pgMR := memmap.MappableRange{uint64(pgstartaddr), uint64(pgendaddr)}
-
-	var (
-		done   uint64
-		retErr error
-	)
-	seg, gap := rw.file.data.Find(uint64(rw.off))
-	for rw.off < end {
-		mr := memmap.MappableRange{uint64(rw.off), uint64(end)}
-		switch {
-		case seg.Ok():
-			// Get internal mappings.
-			ims, err := rw.file.memFile.MapInternal(seg.FileRangeOf(seg.Range().Intersect(mr)), usermem.Write)
-			if err != nil {
-				retErr = err
-				goto exitLoop
-			}
-
-			// Copy to internal mappings.
-			n, err := safemem.CopySeq(ims, srcs)
-			done += n
-			rw.off += uint64(n)
-			srcs = srcs.DropFirst64(n)
-			if err != nil {
-				retErr = err
-				goto exitLoop
-			}
-
-			// Continue.
-			seg, gap = seg.NextNonEmpty()
-
-		case gap.Ok():
-			// Allocate memory for the write.
-			gapMR := gap.Range().Intersect(pgMR)
-			fr, err := rw.file.memFile.Allocate(gapMR.Length(), usage.Tmpfs)
-			if err != nil {
-				retErr = err
-				goto exitLoop
-			}
-
-			// Write to that memory as usual.
-			seg, gap = rw.file.data.Insert(gap, gapMR, fr.Start), fsutil.FileRangeGapIterator{}
-		}
-	}
-exitLoop:
-	// If the write ends beyond the file's previous size, it causes the
-	// file to grow.
-	if rw.off > rw.file.size {
-		atomic.StoreUint64(&rw.file.size, rw.off)
-	}
-
-	rw.file.mu.Unlock()
-	return done, retErr
-}