From 9cdae51feca5cee9faa198161b92a0aeece52d6c Mon Sep 17 00:00:00 2001 From: Adin Scannell Date: Tue, 21 May 2019 15:17:05 -0700 Subject: Add basic plumbing for splice and stub implementation. This does not actually implement an efficient splice or sendfile. Rather, it adds a generic plumbing to the file internals so that this can be added. All file implementations use the stub fileutil.NoSplice implementation, which causes sendfile and splice to fall back to an internal copy. A basic splice system call interface is added, along with a test. PiperOrigin-RevId: 249335960 Change-Id: Ic5568be2af0a505c19e7aec66d5af2480ab0939b --- pkg/sentry/fs/fsutil/file.go | 16 ++++++++++++++++ pkg/sentry/fs/fsutil/inode.go | 3 ++- 2 files changed, 18 insertions(+), 1 deletion(-) (limited to 'pkg/sentry/fs/fsutil') diff --git a/pkg/sentry/fs/fsutil/file.go b/pkg/sentry/fs/fsutil/file.go index e355d8594..9381963d0 100644 --- a/pkg/sentry/fs/fsutil/file.go +++ b/pkg/sentry/fs/fsutil/file.go @@ -223,6 +223,20 @@ func (FileNoIoctl) Ioctl(ctx context.Context, io usermem.IO, args arch.SyscallAr return 0, syserror.ENOTTY } +// FileNoSplice implements fs.FileOperations.ReadFrom and +// fs.FileOperations.WriteTo for files that don't support splice. +type FileNoSplice struct{} + +// WriteTo implements fs.FileOperations.WriteTo. +func (FileNoSplice) WriteTo(context.Context, *fs.File, *fs.File, fs.SpliceOpts) (int64, error) { + return 0, syserror.ENOSYS +} + +// ReadFrom implements fs.FileOperations.ReadFrom. +func (FileNoSplice) ReadFrom(context.Context, *fs.File, *fs.File, fs.SpliceOpts) (int64, error) { + return 0, syserror.ENOSYS +} + // DirFileOperations implements most of fs.FileOperations for directories, // except for Readdir and UnstableAttr which the embedding type must implement. type DirFileOperations struct { @@ -233,6 +247,7 @@ type DirFileOperations struct { FileNoopFlush FileNoopFsync FileNoopRelease + FileNoSplice } // Read implements fs.FileOperations.Read @@ -303,6 +318,7 @@ type NoReadWriteFile struct { FileNoWrite `state:"nosave"` FileNotDirReaddir `state:"nosave"` FileUseInodeUnstableAttr `state:"nosave"` + FileNoSplice `state:"nosave"` } var _ fs.FileOperations = (*NoReadWriteFile)(nil) diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go index a22b6ce9c..925887335 100644 --- a/pkg/sentry/fs/fsutil/inode.go +++ b/pkg/sentry/fs/fsutil/inode.go @@ -250,16 +250,17 @@ func (i *InodeSimpleExtendedAttributes) Listxattr(_ *fs.Inode) (map[string]struc // // +stateify savable type staticFile struct { - waiter.AlwaysReady `state:"nosave"` FileGenericSeek `state:"nosave"` FileNoIoctl `state:"nosave"` FileNoMMap `state:"nosave"` + FileNoSplice `state:"nosave"` FileNoopFsync `state:"nosave"` FileNoopFlush `state:"nosave"` FileNoopRelease `state:"nosave"` FileNoopWrite `state:"nosave"` FileNotDirReaddir `state:"nosave"` FileUseInodeUnstableAttr `state:"nosave"` + waiter.AlwaysReady `state:"nosave"` FileStaticContentReader } -- cgit v1.2.3