Merge release-20200818.0-77-g84f04909c (automated)

1 files changed, 16 insertions, 19 deletions

diff --git a/pkg/sentry/syscalls/linux/vfs2/splice.go b/pkg/sentry/syscalls/linux/vfs2/splice.go
index 75bfa2c79..192411393 100644
--- a/pkg/sentry/syscalls/linux/vfs2/splice.go
+++ b/pkg/sentry/syscalls/linux/vfs2/splice.go
@@ -131,18 +131,14 @@ func Splice(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscal
 		case inIsPipe && outIsPipe:
 			n, err = pipe.Splice(t, outPipeFD, inPipeFD, count)
 		case inIsPipe:
+			n, err = inPipeFD.SpliceToNonPipe(t, outFile, outOffset, count)
 			if outOffset != -1 {
-				n, err = outFile.PWrite(t, inPipeFD.IOSequence(count), outOffset, vfs.WriteOptions{})
 				outOffset += n
-			} else {
-				n, err = outFile.Write(t, inPipeFD.IOSequence(count), vfs.WriteOptions{})
 			}
 		case outIsPipe:
+			n, err = outPipeFD.SpliceFromNonPipe(t, inFile, inOffset, count)
 			if inOffset != -1 {
-				n, err = inFile.PRead(t, outPipeFD.IOSequence(count), inOffset, vfs.ReadOptions{})
 				inOffset += n
-			} else {
-				n, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{})
 			}
 		default:
 			panic("not possible")
@@ -341,17 +337,15 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 	if outIsPipe {
 		for n < count {
 			var spliceN int64
-			if offset != -1 {
-				spliceN, err = inFile.PRead(t, outPipeFD.IOSequence(count), offset, vfs.ReadOptions{})
-				offset += spliceN
-			} else {
-				spliceN, err = inFile.Read(t, outPipeFD.IOSequence(count), vfs.ReadOptions{})
-			}
+			spliceN, err = outPipeFD.SpliceFromNonPipe(t, inFile, offset, count)
 			if spliceN == 0 && err == io.EOF {
 				// We reached the end of the file. Eat the error and exit the loop.
 				err = nil
 				break
 			}
+			if offset != -1 {
+				offset += spliceN
+			}
 			n += spliceN
 			if err == syserror.ErrWouldBlock && !nonBlock {
 				err = dw.waitForBoth(t)
@@ -371,19 +365,18 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 			} else {
 				readN, err = inFile.Read(t, usermem.BytesIOSequence(buf), vfs.ReadOptions{})
 			}
-			if readN == 0 && err == io.EOF {
-				// We reached the end of the file. Eat the error and exit the loop.
-				err = nil
+			if readN == 0 && err != nil {
+				if err == io.EOF {
+					// We reached the end of the file. Eat the error before exiting the loop.
+					err = nil
+				}
 				break
 			}
 			n += readN
-			if err != nil {
-				break
-			}
 
 			// Write all of the bytes that we read. This may need
 			// multiple write calls to complete.
-			wbuf := buf[:n]
+			wbuf := buf[:readN]
 			for len(wbuf) > 0 {
 				var writeN int64
 				writeN, err = outFile.Write(t, usermem.BytesIOSequence(wbuf), vfs.WriteOptions{})
@@ -398,6 +391,10 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 					notWritten := int64(len(wbuf))
 					n -= notWritten
 					if offset != -1 {
+						// TODO(gvisor.dev/issue/3779): The inFile offset will be incorrect if we
+						// roll back, because it has already been advanced by the full amount.
+						// Merely seeking on inFile does not work, because there may be concurrent
+						// file operations.
 						offset -= notWritten
 					}
 					break