diff options
Diffstat (limited to 'pkg/sentry/safemem/io.go')
-rw-r--r-- | pkg/sentry/safemem/io.go | 392 |
1 files changed, 0 insertions, 392 deletions
diff --git a/pkg/sentry/safemem/io.go b/pkg/sentry/safemem/io.go deleted file mode 100644 index f039a5c34..000000000 --- a/pkg/sentry/safemem/io.go +++ /dev/null @@ -1,392 +0,0 @@ -// Copyright 2018 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 safemem - -import ( - "errors" - "io" - "math" -) - -// ErrEndOfBlockSeq is returned by BlockSeqWriter when attempting to write -// beyond the end of the BlockSeq. -var ErrEndOfBlockSeq = errors.New("write beyond end of BlockSeq") - -// Reader represents a streaming byte source like io.Reader. -type Reader interface { - // ReadToBlocks reads up to dsts.NumBytes() bytes into dsts and returns the - // number of bytes read. It may return a partial read without an error - // (i.e. (n, nil) where 0 < n < dsts.NumBytes()). It should not return a - // full read with an error (i.e. (dsts.NumBytes(), err) where err != nil); - // note that this differs from io.Reader.Read (in particular, io.EOF should - // not be returned if ReadToBlocks successfully reads dsts.NumBytes() - // bytes.) - ReadToBlocks(dsts BlockSeq) (uint64, error) -} - -// Writer represents a streaming byte sink like io.Writer. -type Writer interface { - // WriteFromBlocks writes up to srcs.NumBytes() bytes from srcs and returns - // the number of bytes written. It may return a partial write without an - // error (i.e. (n, nil) where 0 < n < srcs.NumBytes()). It should not - // return a full write with an error (i.e. srcs.NumBytes(), err) where err - // != nil). - WriteFromBlocks(srcs BlockSeq) (uint64, error) -} - -// ReadFullToBlocks repeatedly invokes r.ReadToBlocks until dsts.NumBytes() -// bytes have been read or ReadToBlocks returns an error. -func ReadFullToBlocks(r Reader, dsts BlockSeq) (uint64, error) { - var done uint64 - for !dsts.IsEmpty() { - n, err := r.ReadToBlocks(dsts) - done += n - if err != nil { - return done, err - } - dsts = dsts.DropFirst64(n) - } - return done, nil -} - -// WriteFullFromBlocks repeatedly invokes w.WriteFromBlocks until -// srcs.NumBytes() bytes have been written or WriteFromBlocks returns an error. -func WriteFullFromBlocks(w Writer, srcs BlockSeq) (uint64, error) { - var done uint64 - for !srcs.IsEmpty() { - n, err := w.WriteFromBlocks(srcs) - done += n - if err != nil { - return done, err - } - srcs = srcs.DropFirst64(n) - } - return done, nil -} - -// BlockSeqReader implements Reader by reading from a BlockSeq. -type BlockSeqReader struct { - Blocks BlockSeq -} - -// ReadToBlocks implements Reader.ReadToBlocks. -func (r *BlockSeqReader) ReadToBlocks(dsts BlockSeq) (uint64, error) { - n, err := CopySeq(dsts, r.Blocks) - r.Blocks = r.Blocks.DropFirst64(n) - if err != nil { - return n, err - } - if n < dsts.NumBytes() { - return n, io.EOF - } - return n, nil -} - -// BlockSeqWriter implements Writer by writing to a BlockSeq. -type BlockSeqWriter struct { - Blocks BlockSeq -} - -// WriteFromBlocks implements Writer.WriteFromBlocks. -func (w *BlockSeqWriter) WriteFromBlocks(srcs BlockSeq) (uint64, error) { - n, err := CopySeq(w.Blocks, srcs) - w.Blocks = w.Blocks.DropFirst64(n) - if err != nil { - return n, err - } - if n < srcs.NumBytes() { - return n, ErrEndOfBlockSeq - } - return n, nil -} - -// ReaderFunc implements Reader for a function with the semantics of -// Reader.ReadToBlocks. -type ReaderFunc func(dsts BlockSeq) (uint64, error) - -// ReadToBlocks implements Reader.ReadToBlocks. -func (f ReaderFunc) ReadToBlocks(dsts BlockSeq) (uint64, error) { - return f(dsts) -} - -// WriterFunc implements Writer for a function with the semantics of -// Writer.WriteFromBlocks. -type WriterFunc func(srcs BlockSeq) (uint64, error) - -// WriteFromBlocks implements Writer.WriteFromBlocks. -func (f WriterFunc) WriteFromBlocks(srcs BlockSeq) (uint64, error) { - return f(srcs) -} - -// ToIOReader implements io.Reader for a (safemem.)Reader. -// -// ToIOReader will return a successful partial read iff Reader.ReadToBlocks does -// so. -type ToIOReader struct { - Reader Reader -} - -// Read implements io.Reader.Read. -func (r ToIOReader) Read(dst []byte) (int, error) { - n, err := r.Reader.ReadToBlocks(BlockSeqOf(BlockFromSafeSlice(dst))) - return int(n), err -} - -// ToIOWriter implements io.Writer for a (safemem.)Writer. -type ToIOWriter struct { - Writer Writer -} - -// Write implements io.Writer.Write. -func (w ToIOWriter) Write(src []byte) (int, error) { - // io.Writer does not permit partial writes. - n, err := WriteFullFromBlocks(w.Writer, BlockSeqOf(BlockFromSafeSlice(src))) - return int(n), err -} - -// FromIOReader implements Reader for an io.Reader by repeatedly invoking -// io.Reader.Read until it returns an error or partial read. This is not -// thread-safe. -// -// FromIOReader will return a successful partial read iff Reader.Read does so. -type FromIOReader struct { - Reader io.Reader -} - -// ReadToBlocks implements Reader.ReadToBlocks. -func (r FromIOReader) ReadToBlocks(dsts BlockSeq) (uint64, error) { - var buf []byte - var done uint64 - for !dsts.IsEmpty() { - dst := dsts.Head() - var n int - var err error - n, buf, err = r.readToBlock(dst, buf) - done += uint64(n) - if n != dst.Len() { - return done, err - } - dsts = dsts.Tail() - if err != nil { - if dsts.IsEmpty() && err == io.EOF { - return done, nil - } - return done, err - } - } - return done, nil -} - -func (r FromIOReader) readToBlock(dst Block, buf []byte) (int, []byte, error) { - // io.Reader isn't safecopy-aware, so we have to buffer Blocks that require - // safecopy. - if !dst.NeedSafecopy() { - n, err := r.Reader.Read(dst.ToSlice()) - return n, buf, err - } - if len(buf) < dst.Len() { - buf = make([]byte, dst.Len()) - } - rn, rerr := r.Reader.Read(buf[:dst.Len()]) - wbn, wberr := Copy(dst, BlockFromSafeSlice(buf[:rn])) - if wberr != nil { - return wbn, buf, wberr - } - return wbn, buf, rerr -} - -// FromIOReaderAt implements Reader for an io.ReaderAt. Does not repeatedly -// invoke io.ReaderAt.ReadAt because ReadAt is more strict than Read. A partial -// read indicates an error. This is not thread-safe. -type FromIOReaderAt struct { - ReaderAt io.ReaderAt - Offset int64 -} - -// ReadToBlocks implements Reader.ReadToBlocks. -func (r FromIOReaderAt) ReadToBlocks(dsts BlockSeq) (uint64, error) { - var buf []byte - var done uint64 - for !dsts.IsEmpty() { - dst := dsts.Head() - var n int - var err error - n, buf, err = r.readToBlock(dst, buf) - done += uint64(n) - if n != dst.Len() { - return done, err - } - dsts = dsts.Tail() - if err != nil { - if dsts.IsEmpty() && err == io.EOF { - return done, nil - } - return done, err - } - } - return done, nil -} - -func (r FromIOReaderAt) readToBlock(dst Block, buf []byte) (int, []byte, error) { - // io.Reader isn't safecopy-aware, so we have to buffer Blocks that require - // safecopy. - if !dst.NeedSafecopy() { - n, err := r.ReaderAt.ReadAt(dst.ToSlice(), r.Offset) - r.Offset += int64(n) - return n, buf, err - } - if len(buf) < dst.Len() { - buf = make([]byte, dst.Len()) - } - rn, rerr := r.ReaderAt.ReadAt(buf[:dst.Len()], r.Offset) - r.Offset += int64(rn) - wbn, wberr := Copy(dst, BlockFromSafeSlice(buf[:rn])) - if wberr != nil { - return wbn, buf, wberr - } - return wbn, buf, rerr -} - -// FromIOWriter implements Writer for an io.Writer by repeatedly invoking -// io.Writer.Write until it returns an error or partial write. -// -// FromIOWriter will tolerate implementations of io.Writer.Write that return -// partial writes with a nil error in contravention of io.Writer's -// requirements, since Writer is permitted to do so. FromIOWriter will return a -// successful partial write iff Writer.Write does so. -type FromIOWriter struct { - Writer io.Writer -} - -// WriteFromBlocks implements Writer.WriteFromBlocks. -func (w FromIOWriter) WriteFromBlocks(srcs BlockSeq) (uint64, error) { - var buf []byte - var done uint64 - for !srcs.IsEmpty() { - src := srcs.Head() - var n int - var err error - n, buf, err = w.writeFromBlock(src, buf) - done += uint64(n) - if n != src.Len() || err != nil { - return done, err - } - srcs = srcs.Tail() - } - return done, nil -} - -func (w FromIOWriter) writeFromBlock(src Block, buf []byte) (int, []byte, error) { - // io.Writer isn't safecopy-aware, so we have to buffer Blocks that require - // safecopy. - if !src.NeedSafecopy() { - n, err := w.Writer.Write(src.ToSlice()) - return n, buf, err - } - if len(buf) < src.Len() { - buf = make([]byte, src.Len()) - } - bufn, buferr := Copy(BlockFromSafeSlice(buf[:src.Len()]), src) - wn, werr := w.Writer.Write(buf[:bufn]) - if werr != nil { - return wn, buf, werr - } - return wn, buf, buferr -} - -// FromVecReaderFunc implements Reader for a function that reads data into a -// [][]byte and returns the number of bytes read as an int64. -type FromVecReaderFunc struct { - ReadVec func(dsts [][]byte) (int64, error) -} - -// ReadToBlocks implements Reader.ReadToBlocks. -// -// ReadToBlocks calls r.ReadVec at most once. -func (r FromVecReaderFunc) ReadToBlocks(dsts BlockSeq) (uint64, error) { - if dsts.IsEmpty() { - return 0, nil - } - // Ensure that we don't pass a [][]byte with a total length > MaxInt64. - dsts = dsts.TakeFirst64(uint64(math.MaxInt64)) - dstSlices := make([][]byte, 0, dsts.NumBlocks()) - // Buffer Blocks that require safecopy. - for tmp := dsts; !tmp.IsEmpty(); tmp = tmp.Tail() { - dst := tmp.Head() - if dst.NeedSafecopy() { - dstSlices = append(dstSlices, make([]byte, dst.Len())) - } else { - dstSlices = append(dstSlices, dst.ToSlice()) - } - } - rn, rerr := r.ReadVec(dstSlices) - dsts = dsts.TakeFirst64(uint64(rn)) - var done uint64 - var i int - for !dsts.IsEmpty() { - dst := dsts.Head() - if dst.NeedSafecopy() { - n, err := Copy(dst, BlockFromSafeSlice(dstSlices[i])) - done += uint64(n) - if err != nil { - return done, err - } - } else { - done += uint64(dst.Len()) - } - dsts = dsts.Tail() - i++ - } - return done, rerr -} - -// FromVecWriterFunc implements Writer for a function that writes data from a -// [][]byte and returns the number of bytes written. -type FromVecWriterFunc struct { - WriteVec func(srcs [][]byte) (int64, error) -} - -// WriteFromBlocks implements Writer.WriteFromBlocks. -// -// WriteFromBlocks calls w.WriteVec at most once. -func (w FromVecWriterFunc) WriteFromBlocks(srcs BlockSeq) (uint64, error) { - if srcs.IsEmpty() { - return 0, nil - } - // Ensure that we don't pass a [][]byte with a total length > MaxInt64. - srcs = srcs.TakeFirst64(uint64(math.MaxInt64)) - srcSlices := make([][]byte, 0, srcs.NumBlocks()) - // Buffer Blocks that require safecopy. - var buferr error - for tmp := srcs; !tmp.IsEmpty(); tmp = tmp.Tail() { - src := tmp.Head() - if src.NeedSafecopy() { - slice := make([]byte, src.Len()) - n, err := Copy(BlockFromSafeSlice(slice), src) - srcSlices = append(srcSlices, slice[:n]) - if err != nil { - buferr = err - break - } - } else { - srcSlices = append(srcSlices, src.ToSlice()) - } - } - n, err := w.WriteVec(srcSlices) - if err != nil { - return uint64(n), err - } - return uint64(n), buferr -} |