diff options
Diffstat (limited to 'pkg/sentry/kernel')
-rw-r--r-- | pkg/sentry/kernel/pipe/pipe.go | 14 | ||||
-rw-r--r-- | pkg/sentry/kernel/pipe/vfs.go | 63 |
2 files changed, 59 insertions, 18 deletions
diff --git a/pkg/sentry/kernel/pipe/pipe.go b/pkg/sentry/kernel/pipe/pipe.go index 297e8f28f..c410c96aa 100644 --- a/pkg/sentry/kernel/pipe/pipe.go +++ b/pkg/sentry/kernel/pipe/pipe.go @@ -200,17 +200,17 @@ type readOps struct { // // Precondition: this pipe must have readers. func (p *Pipe) read(ctx context.Context, ops readOps) (int64, error) { - // Don't block for a zero-length read even if the pipe is empty. - if ops.left() == 0 { - return 0, nil - } - p.mu.Lock() defer p.mu.Unlock() return p.readLocked(ctx, ops) } func (p *Pipe) readLocked(ctx context.Context, ops readOps) (int64, error) { + // Don't block for a zero-length read even if the pipe is empty. + if ops.left() == 0 { + return 0, nil + } + // Is the pipe empty? if p.view.Size() == 0 { if !p.HasWriters() { @@ -388,6 +388,10 @@ func (p *Pipe) rwReadiness() waiter.EventMask { func (p *Pipe) queued() int64 { p.mu.Lock() defer p.mu.Unlock() + return p.queuedLocked() +} + +func (p *Pipe) queuedLocked() int64 { return p.view.Size() } diff --git a/pkg/sentry/kernel/pipe/vfs.go b/pkg/sentry/kernel/pipe/vfs.go index 28f998e45..f223d59e1 100644 --- a/pkg/sentry/kernel/pipe/vfs.go +++ b/pkg/sentry/kernel/pipe/vfs.go @@ -244,19 +244,57 @@ func (fd *VFSPipeFD) SetPipeSize(size int64) (int64, error) { return fd.pipe.SetFifoSize(size) } -// IOSequence returns a useremm.IOSequence that reads up to count bytes from, -// or writes up to count bytes to, fd. -func (fd *VFSPipeFD) IOSequence(count int64) usermem.IOSequence { - return usermem.IOSequence{ +// SpliceToNonPipe performs a splice operation from fd to a non-pipe file. +func (fd *VFSPipeFD) SpliceToNonPipe(ctx context.Context, out *vfs.FileDescription, off, count int64) (int64, error) { + fd.pipe.mu.Lock() + defer fd.pipe.mu.Unlock() + + // Cap the sequence at number of bytes actually available. + v := fd.pipe.queuedLocked() + if v < count { + count = v + } + src := usermem.IOSequence{ IO: fd, Addrs: usermem.AddrRangeSeqOf(usermem.AddrRange{0, usermem.Addr(count)}), } + + var ( + n int64 + err error + ) + if off == -1 { + n, err = out.Write(ctx, src, vfs.WriteOptions{}) + } else { + n, err = out.PWrite(ctx, src, off, vfs.WriteOptions{}) + } + if n > 0 { + fd.pipe.view.TrimFront(n) + } + return n, err +} + +// SpliceFromNonPipe performs a splice operation from a non-pipe file to fd. +func (fd *VFSPipeFD) SpliceFromNonPipe(ctx context.Context, in *vfs.FileDescription, off, count int64) (int64, error) { + fd.pipe.mu.Lock() + defer fd.pipe.mu.Unlock() + + dst := usermem.IOSequence{ + IO: fd, + Addrs: usermem.AddrRangeSeqOf(usermem.AddrRange{0, usermem.Addr(count)}), + } + + if off == -1 { + return in.Read(ctx, dst, vfs.ReadOptions{}) + } + return in.PRead(ctx, dst, off, vfs.ReadOptions{}) } -// CopyIn implements usermem.IO.CopyIn. +// CopyIn implements usermem.IO.CopyIn. Note that it is the caller's +// responsibility to trim fd.pipe.view after the read is completed. func (fd *VFSPipeFD) CopyIn(ctx context.Context, addr usermem.Addr, dst []byte, opts usermem.IOOpts) (int, error) { origCount := int64(len(dst)) - n, err := fd.pipe.read(ctx, readOps{ + n, err := fd.pipe.readLocked(ctx, readOps{ left: func() int64 { return int64(len(dst)) }, @@ -265,7 +303,6 @@ func (fd *VFSPipeFD) CopyIn(ctx context.Context, addr usermem.Addr, dst []byte, }, read: func(view *buffer.View) (int64, error) { n, err := view.ReadAt(dst, 0) - view.TrimFront(int64(n)) return int64(n), err }, }) @@ -281,7 +318,7 @@ func (fd *VFSPipeFD) CopyIn(ctx context.Context, addr usermem.Addr, dst []byte, // CopyOut implements usermem.IO.CopyOut. func (fd *VFSPipeFD) CopyOut(ctx context.Context, addr usermem.Addr, src []byte, opts usermem.IOOpts) (int, error) { origCount := int64(len(src)) - n, err := fd.pipe.write(ctx, writeOps{ + n, err := fd.pipe.writeLocked(ctx, writeOps{ left: func() int64 { return int64(len(src)) }, @@ -305,7 +342,7 @@ func (fd *VFSPipeFD) CopyOut(ctx context.Context, addr usermem.Addr, src []byte, // ZeroOut implements usermem.IO.ZeroOut. func (fd *VFSPipeFD) ZeroOut(ctx context.Context, addr usermem.Addr, toZero int64, opts usermem.IOOpts) (int64, error) { origCount := toZero - n, err := fd.pipe.write(ctx, writeOps{ + n, err := fd.pipe.writeLocked(ctx, writeOps{ left: func() int64 { return toZero }, @@ -326,14 +363,15 @@ func (fd *VFSPipeFD) ZeroOut(ctx context.Context, addr usermem.Addr, toZero int6 return n, err } -// CopyInTo implements usermem.IO.CopyInTo. +// CopyInTo implements usermem.IO.CopyInTo. Note that it is the caller's +// responsibility to trim fd.pipe.view after the read is completed. func (fd *VFSPipeFD) CopyInTo(ctx context.Context, ars usermem.AddrRangeSeq, dst safemem.Writer, opts usermem.IOOpts) (int64, error) { count := ars.NumBytes() if count == 0 { return 0, nil } origCount := count - n, err := fd.pipe.read(ctx, readOps{ + n, err := fd.pipe.readLocked(ctx, readOps{ left: func() int64 { return count }, @@ -342,7 +380,6 @@ func (fd *VFSPipeFD) CopyInTo(ctx context.Context, ars usermem.AddrRangeSeq, dst }, read: func(view *buffer.View) (int64, error) { n, err := view.ReadToSafememWriter(dst, uint64(count)) - view.TrimFront(int64(n)) return int64(n), err }, }) @@ -362,7 +399,7 @@ func (fd *VFSPipeFD) CopyOutFrom(ctx context.Context, ars usermem.AddrRangeSeq, return 0, nil } origCount := count - n, err := fd.pipe.write(ctx, writeOps{ + n, err := fd.pipe.writeLocked(ctx, writeOps{ left: func() int64 { return count }, |