diff --git a/runtime/v1/linux/proc/io.go b/runtime/v1/linux/proc/io.go index aed349a8607d..7091e869c9d2 100644 --- a/runtime/v1/linux/proc/io.go +++ b/runtime/v1/linux/proc/io.go @@ -24,8 +24,10 @@ import ( "io" "os" "sync" + "sync/atomic" "syscall" + "github.com/containerd/containerd/log" "github.com/containerd/fifo" runc "github.com/containerd/go-runc" ) @@ -38,7 +40,7 @@ var bufPool = sync.Pool{ } func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, wg, cwg *sync.WaitGroup) error { - var sameFile io.WriteCloser + var sameFile *countingWriteCloser for _, i := range []struct { name string dest func(wc io.WriteCloser, rc io.Closer) @@ -52,7 +54,9 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w cwg.Done() p := bufPool.Get().(*[]byte) defer bufPool.Put(p) - io.CopyBuffer(wc, rio.Stdout(), *p) + if _, err := io.CopyBuffer(wc, rio.Stdout(), *p); err != nil { + log.G(ctx).Warn("error copying stdout") + } wg.Done() wc.Close() if rc != nil { @@ -69,7 +73,9 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w cwg.Done() p := bufPool.Get().(*[]byte) defer bufPool.Put(p) - io.CopyBuffer(wc, rio.Stderr(), *p) + if _, err := io.CopyBuffer(wc, rio.Stderr(), *p); err != nil { + log.G(ctx).Warn("error copying stderr") + } wg.Done() wc.Close() if rc != nil { @@ -96,6 +102,7 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w } } else { if sameFile != nil { + sameFile.count++ i.dest(sameFile, nil) continue } @@ -103,7 +110,10 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w return fmt.Errorf("containerd-shim: opening %s failed: %s", i.name, err) } if stdout == stderr { - sameFile = fw + sameFile = &countingWriteCloser{ + WriteCloser: fw, + count: 1, + } } } i.dest(fw, fr) @@ -128,6 +138,19 @@ func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, w return nil } +// countingWriteCloser masks io.Closer() until close has been invoked a certain number of times. +type countingWriteCloser struct { + io.WriteCloser + count int64 +} + +func (c *countingWriteCloser) Close() error { + if atomic.AddInt64(&c.count, -1) > 0 { + return nil + } + return c.WriteCloser.Close() +} + // isFifo checks if a file is a fifo // if the file does not exist then it returns false func isFifo(path string) (bool, error) {