diff options
Diffstat (limited to 'pkg/sentry/syscalls')
| -rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/splice.go | 22 |
1 files changed, 14 insertions, 8 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/splice.go b/pkg/sentry/syscalls/linux/vfs2/splice.go index 68ce94778..5543cfac2 100644 --- a/pkg/sentry/syscalls/linux/vfs2/splice.go +++ b/pkg/sentry/syscalls/linux/vfs2/splice.go @@ -18,6 +18,7 @@ import ( "io" "gvisor.dev/gvisor/pkg/abi/linux" + "gvisor.dev/gvisor/pkg/log" "gvisor.dev/gvisor/pkg/sentry/arch" "gvisor.dev/gvisor/pkg/sentry/kernel" "gvisor.dev/gvisor/pkg/sentry/kernel/pipe" @@ -390,16 +391,21 @@ func Sendfile(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc err = dw.waitForOut(t) } if err != nil { - // We didn't complete the write. Only - // report the bytes that were actually - // written, and rewind the offset. + // We didn't complete the write. Only report the bytes that were actually + // written, and rewind offsets as needed. 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. + if offset == -1 { + // We modified the offset of the input file itself during the read + // operation. Rewind it. + if _, seekErr := inFile.Seek(t, -notWritten, linux.SEEK_CUR); seekErr != nil { + // Log the error but don't return it, since the write has already + // completed successfully. + log.Warningf("failed to roll back input file offset: %v", seekErr) + } + } else { + // The sendfile call was provided an offset parameter that should be + // adjusted to reflect the number of bytes sent. Rewind it. offset -= notWritten } break |