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authorAdin Scannell <ascannell@google.com>2020-05-05 18:06:46 -0700
committerAdin Scannell <ascannell@google.com>2020-05-19 21:24:22 -0700
commit7f8172edf583e0d26bee5e06578a442c7507ba6f (patch)
tree05060a421333308720ced12c4dd72e95b500999f /pkg/shim/v1/proc/io.go
parent104a0ad08c8346a17d56287beb9756b8d52f684f (diff)
Restructure shim packages for merging.
Diffstat (limited to 'pkg/shim/v1/proc/io.go')
-rw-r--r--pkg/shim/v1/proc/io.go167
1 files changed, 167 insertions, 0 deletions
diff --git a/pkg/shim/v1/proc/io.go b/pkg/shim/v1/proc/io.go
new file mode 100644
index 000000000..2677b4e54
--- /dev/null
+++ b/pkg/shim/v1/proc/io.go
@@ -0,0 +1,167 @@
+// Copyright 2018 The containerd Authors.
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package proc
+
+import (
+ "context"
+ "fmt"
+ "io"
+ "os"
+ "sync"
+ "sync/atomic"
+ "syscall"
+
+ "github.com/containerd/containerd/log"
+ "github.com/containerd/fifo"
+ runc "github.com/containerd/go-runc"
+)
+
+// TODO(random-liu): This file can be a util.
+
+var bufPool = sync.Pool{
+ New: func() interface{} {
+ buffer := make([]byte, 32<<10)
+ return &buffer
+ },
+}
+
+func copyPipes(ctx context.Context, rio runc.IO, stdin, stdout, stderr string, wg, cwg *sync.WaitGroup) error {
+ var sameFile *countingWriteCloser
+ for _, i := range []struct {
+ name string
+ dest func(wc io.WriteCloser, rc io.Closer)
+ }{
+ {
+ name: stdout,
+ dest: func(wc io.WriteCloser, rc io.Closer) {
+ wg.Add(1)
+ cwg.Add(1)
+ go func() {
+ cwg.Done()
+ p := bufPool.Get().(*[]byte)
+ defer bufPool.Put(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 {
+ rc.Close()
+ }
+ }()
+ },
+ }, {
+ name: stderr,
+ dest: func(wc io.WriteCloser, rc io.Closer) {
+ wg.Add(1)
+ cwg.Add(1)
+ go func() {
+ cwg.Done()
+ p := bufPool.Get().(*[]byte)
+ defer bufPool.Put(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 {
+ rc.Close()
+ }
+ }()
+ },
+ },
+ } {
+ ok, err := isFifo(i.name)
+ if err != nil {
+ return err
+ }
+ var (
+ fw io.WriteCloser
+ fr io.Closer
+ )
+ if ok {
+ if fw, err = fifo.OpenFifo(ctx, i.name, syscall.O_WRONLY, 0); err != nil {
+ return fmt.Errorf("gvisor-containerd-shim: opening %s failed: %s", i.name, err)
+ }
+ if fr, err = fifo.OpenFifo(ctx, i.name, syscall.O_RDONLY, 0); err != nil {
+ return fmt.Errorf("gvisor-containerd-shim: opening %s failed: %s", i.name, err)
+ }
+ } else {
+ if sameFile != nil {
+ sameFile.count++
+ i.dest(sameFile, nil)
+ continue
+ }
+ if fw, err = os.OpenFile(i.name, syscall.O_WRONLY|syscall.O_APPEND, 0); err != nil {
+ return fmt.Errorf("gvisor-containerd-shim: opening %s failed: %s", i.name, err)
+ }
+ if stdout == stderr {
+ sameFile = &countingWriteCloser{
+ WriteCloser: fw,
+ count: 1,
+ }
+ }
+ }
+ i.dest(fw, fr)
+ }
+ if stdin == "" {
+ return nil
+ }
+ f, err := fifo.OpenFifo(context.Background(), stdin, syscall.O_RDONLY|syscall.O_NONBLOCK, 0)
+ if err != nil {
+ return fmt.Errorf("gvisor-containerd-shim: opening %s failed: %s", stdin, err)
+ }
+ cwg.Add(1)
+ go func() {
+ cwg.Done()
+ p := bufPool.Get().(*[]byte)
+ defer bufPool.Put(p)
+
+ io.CopyBuffer(rio.Stdin(), f, *p)
+ rio.Stdin().Close()
+ f.Close()
+ }()
+ 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) {
+ stat, err := os.Stat(path)
+ if err != nil {
+ if os.IsNotExist(err) {
+ return false, nil
+ }
+ return false, err
+ }
+ if stat.Mode()&os.ModeNamedPipe == os.ModeNamedPipe {
+ return true, nil
+ }
+ return false, nil
+}