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Internal change. 

PiperOrigin-RevId: 311046755
This commit is contained in:
Jamie Liu 2020-05-11 20:02:09 -07:00 committed by gVisor bot
parent 15de8cc9e0
commit 94251aedb4
2 changed files with 39 additions and 24 deletions
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33
pkg/sentry/fsimpl/gofer/filesystem.go
View File

@ -877,10 +877,15 @@ func (d *dentry) openSpecialFileLocked(ctx context.Context, mnt *vfs.Mount, opts
if err != nil {
return nil, err
}
seekable := d.fileType() == linux.S_IFREG
fd := &specialFileFD{
handle: h,
seekable: seekable,
}
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{
DenyPRead: !seekable,
DenyPWrite: !seekable,
}); err != nil {
h.close(ctx)
return nil, err
}
@ -911,7 +916,11 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
creds := rp.Credentials()
name := rp.Component()
fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, (p9.OpenFlags)(opts.Flags), (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
// Filter file creation flags and O_LARGEFILE out; the create RPC already
// has the semantics of O_CREAT|O_EXCL, while some servers will choke on
// O_LARGEFILE.
createFlags := p9.OpenFlags(opts.Flags &^ (linux.O_CREAT | linux.O_EXCL | linux.O_NOCTTY | linux.O_TRUNC | linux.O_LARGEFILE))
fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, createFlags, (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
if err != nil {
dirfile.close(ctx)
return nil, err
@ -919,7 +928,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
// Then we need to walk to the file we just created to get a non-open fid
// representing it, and to get its metadata. This must use d.file since, as
// explained above, dirfile was invalidated by dirfile.Create().
walkQID, nonOpenFile, attrMask, attr, err := d.file.walkGetAttrOne(ctx, name)
_, nonOpenFile, attrMask, attr, err := d.file.walkGetAttrOne(ctx, name)
if err != nil {
openFile.close(ctx)
if fdobj != nil {
@ -927,17 +936,6 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
return nil, err
}
// Sanity-check that we walked to the file we created.
if createQID.Path != walkQID.Path {
// Probably due to concurrent remote filesystem mutation?
ctx.Warningf("gofer.dentry.createAndOpenChildLocked: created file has QID %v before walk, QID %v after (interop=%v)", createQID, walkQID, d.fs.opts.interop)
nonOpenFile.close(ctx)
openFile.close(ctx)
if fdobj != nil {
fdobj.Close()
}
return nil, syserror.EAGAIN
}
// Construct the new dentry.
child, err := d.fs.newDentry(ctx, nonOpenFile, createQID, attrMask, &attr)
@ -983,16 +981,21 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
childVFSFD = &fd.vfsfd
} else {
seekable := child.fileType() == linux.S_IFREG
fd := &specialFileFD{
handle: handle{
file: openFile,
fd: -1,
},
seekable: seekable,
}
if fdobj != nil {
fd.handle.fd = int32(fdobj.Release())
}
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{
DenyPRead: !seekable,
DenyPWrite: !seekable,
}); err != nil {
fd.handle.close(ctx)
return nil, err
}

28
pkg/sentry/fsimpl/gofer/special_file.go
View File

@ -33,13 +33,14 @@ import (
type specialFileFD struct {
fileDescription
// handle is immutable.
// handle is used for file I/O. handle is immutable.
handle handle
// off is the file offset. off is protected by mu. (POSIX 2.9.7 only
// requires operations using the file offset to be atomic for regular files
// and symlinks; however, since specialFileFD may be used for regular
// files, we apply this atomicity unconditionally.)
// seekable is true if this file description represents a file for which
// file offset is significant, i.e. a regular file. seekable is immutable.
seekable bool
// If seekable is true, off is the file offset. off is protected by mu.
mu sync.Mutex
off int64
}
@ -63,7 +64,7 @@ func (fd *specialFileFD) OnClose(ctx context.Context) error {
// PRead implements vfs.FileDescriptionImpl.PRead.
func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
if offset < 0 {
if fd.seekable && offset < 0 {
return 0, syserror.EINVAL
}
if opts.Flags != 0 {
@ -91,6 +92,10 @@ func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offs
// Read implements vfs.FileDescriptionImpl.Read.
func (fd *specialFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
if !fd.seekable {
return fd.PRead(ctx, dst, -1, opts)
}
fd.mu.Lock()
n, err := fd.PRead(ctx, dst, fd.off, opts)
fd.off += n
@ -100,14 +105,14 @@ func (fd *specialFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts
// PWrite implements vfs.FileDescriptionImpl.PWrite.
func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
if offset < 0 {
if fd.seekable && offset < 0 {
return 0, syserror.EINVAL
}
if opts.Flags != 0 {
return 0, syserror.EOPNOTSUPP
}
if fd.dentry().fileType() == linux.S_IFREG {
if fd.seekable {
limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes())
if err != nil {
return 0, err
@ -130,6 +135,10 @@ func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
// Write implements vfs.FileDescriptionImpl.Write.
func (fd *specialFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
if !fd.seekable {
return fd.PWrite(ctx, src, -1, opts)
}
fd.mu.Lock()
n, err := fd.PWrite(ctx, src, fd.off, opts)
fd.off += n
@ -139,6 +148,9 @@ func (fd *specialFileFD) Write(ctx context.Context, src usermem.IOSequence, opts
// Seek implements vfs.FileDescriptionImpl.Seek.
func (fd *specialFileFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
if !fd.seekable {
return 0, syserror.ESPIPE
}
fd.mu.Lock()
defer fd.mu.Unlock()
switch whence {