diff options
| -rw-r--r-- | pkg/sentry/usermem/bytes_io.go | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/pkg/sentry/usermem/bytes_io.go b/pkg/sentry/usermem/bytes_io.go index 8d88396ba..7898851b3 100644 --- a/pkg/sentry/usermem/bytes_io.go +++ b/pkg/sentry/usermem/bytes_io.go @@ -102,19 +102,34 @@ func (b *BytesIO) rangeCheck(addr Addr, length int) (int, error) { } func (b *BytesIO) blocksFromAddrRanges(ars AddrRangeSeq) (safemem.BlockSeq, error) { - blocks := make([]safemem.Block, 0, ars.NumRanges()) - for !ars.IsEmpty() { - ar := ars.Head() - n, err := b.rangeCheck(ar.Start, int(ar.Length())) - if n != 0 { - blocks = append(blocks, safemem.BlockFromSafeSlice(b.Bytes[int(ar.Start):int(ar.Start)+n])) + switch ars.NumRanges() { + case 0: + return safemem.BlockSeq{}, nil + case 1: + block, err := b.blockFromAddrRange(ars.Head()) + return safemem.BlockSeqOf(block), err + default: + blocks := make([]safemem.Block, 0, ars.NumRanges()) + for !ars.IsEmpty() { + block, err := b.blockFromAddrRange(ars.Head()) + if block.Len() != 0 { + blocks = append(blocks, block) + } + if err != nil { + return safemem.BlockSeqFromSlice(blocks), err + } + ars = ars.Tail() } - if err != nil { - return safemem.BlockSeqFromSlice(blocks), err - } - ars = ars.Tail() + return safemem.BlockSeqFromSlice(blocks), nil + } +} + +func (b *BytesIO) blockFromAddrRange(ar AddrRange) (safemem.Block, error) { + n, err := b.rangeCheck(ar.Start, int(ar.Length())) + if n == 0 { + return safemem.Block{}, err } - return safemem.BlockSeqFromSlice(blocks), nil + return safemem.BlockFromSafeSlice(b.Bytes[int(ar.Start) : int(ar.Start)+n]), err } // BytesIOSequence returns an IOSequence representing the given byte slice. |