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//go:build !windows
/*
Copyright The containerd 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
http://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 diff
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"os"
"os/exec"
"sync"
"github.com/containerd/containerd/protobuf"
"github.com/containerd/containerd/protobuf/proto"
"github.com/containerd/typeurl/v2"
)
// NewBinaryProcessor returns a binary processor for use with processing content streams
func NewBinaryProcessor(ctx context.Context, imt, rmt string, stream StreamProcessor, name string, args, env []string, payload typeurl.Any) (StreamProcessor, error) {
cmd := exec.CommandContext(ctx, name, args...)
cmd.Env = os.Environ()
cmd.Env = append(cmd.Env, env...)
var payloadC io.Closer
if payload != nil {
pb := protobuf.FromAny(payload)
data, err := proto.Marshal(pb)
if err != nil {
return nil, err
}
r, w, err := os.Pipe()
if err != nil {
return nil, err
}
go func() {
io.Copy(w, bytes.NewReader(data))
w.Close()
}()
cmd.ExtraFiles = append(cmd.ExtraFiles, r)
payloadC = r
}
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", mediaTypeEnvVar, imt))
var (
stdin io.Reader
closer func() error
err error
)
if f, ok := stream.(RawProcessor); ok {
stdin = f.File()
closer = f.File().Close
} else {
stdin = stream
}
cmd.Stdin = stdin
r, w, err := os.Pipe()
if err != nil {
return nil, err
}
cmd.Stdout = w
stderr := bytes.NewBuffer(nil)
cmd.Stderr = stderr
if err := cmd.Start(); err != nil {
return nil, err
}
p := &binaryProcessor{
cmd: cmd,
r: r,
mt: rmt,
stderr: stderr,
done: make(chan struct{}),
}
go p.wait()
// close after start and dup
w.Close()
if closer != nil {
closer()
}
if payloadC != nil {
payloadC.Close()
}
return p, nil
}
type binaryProcessor struct {
cmd *exec.Cmd
r *os.File
mt string
stderr *bytes.Buffer
mu sync.Mutex
err error
// There is a race condition between waiting on c.cmd.Wait() and setting c.err within
// c.wait(), and reading that value from c.Err().
// Use done to wait for the returned error to be captured and set.
done chan struct{}
}
func (c *binaryProcessor) Err() error {
c.mu.Lock()
defer c.mu.Unlock()
return c.err
}
func (c *binaryProcessor) wait() {
if err := c.cmd.Wait(); err != nil {
if _, ok := err.(*exec.ExitError); ok {
c.mu.Lock()
c.err = errors.New(c.stderr.String())
c.mu.Unlock()
}
}
close(c.done)
}
func (c *binaryProcessor) Wait(ctx context.Context) error {
select {
case <-c.done:
return c.Err()
case <-ctx.Done():
return ctx.Err()
}
}
func (c *binaryProcessor) File() *os.File {
return c.r
}
func (c *binaryProcessor) MediaType() string {
return c.mt
}
func (c *binaryProcessor) Read(p []byte) (int, error) {
return c.r.Read(p)
}
func (c *binaryProcessor) Close() error {
err := c.r.Close()
if kerr := c.cmd.Process.Kill(); err == nil {
err = kerr
}
return err
}
|
