Move cio to pkg/cio

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/cio/io_unix.go

@@ -0,0 +1,160 @@
+//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 cio
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+	"syscall"
+
+	"github.com/containerd/fifo"
+)
+
+// NewFIFOSetInDir returns a new FIFOSet with paths in a temporary directory under root
+func NewFIFOSetInDir(root, id string, terminal bool) (*FIFOSet, error) {
+	if root != "" {
+		if err := os.MkdirAll(root, 0700); err != nil {
+			return nil, err
+		}
+	}
+	dir, err := os.MkdirTemp(root, "")
+	if err != nil {
+		return nil, err
+	}
+	closer := func() error {
+		return os.RemoveAll(dir)
+	}
+	return NewFIFOSet(Config{
+		Stdin:    filepath.Join(dir, id+"-stdin"),
+		Stdout:   filepath.Join(dir, id+"-stdout"),
+		Stderr:   filepath.Join(dir, id+"-stderr"),
+		Terminal: terminal,
+	}, closer), nil
+}
+
+func copyIO(fifos *FIFOSet, ioset *Streams) (*cio, error) {
+	var ctx, cancel = context.WithCancel(context.Background())
+	pipes, err := openFifos(ctx, fifos)
+	if err != nil {
+		cancel()
+		return nil, err
+	}
+
+	if fifos.Stdin != "" {
+		go func() {
+			p := bufPool.Get().(*[]byte)
+			defer bufPool.Put(p)
+
+			io.CopyBuffer(pipes.Stdin, ioset.Stdin, *p)
+			pipes.Stdin.Close()
+		}()
+	}
+
+	var wg = &sync.WaitGroup{}
+	if fifos.Stdout != "" {
+		wg.Add(1)
+		go func() {
+			p := bufPool.Get().(*[]byte)
+			defer bufPool.Put(p)
+
+			io.CopyBuffer(ioset.Stdout, pipes.Stdout, *p)
+			pipes.Stdout.Close()
+			wg.Done()
+		}()
+	}
+
+	if !fifos.Terminal && fifos.Stderr != "" {
+		wg.Add(1)
+		go func() {
+			p := bufPool.Get().(*[]byte)
+			defer bufPool.Put(p)
+
+			io.CopyBuffer(ioset.Stderr, pipes.Stderr, *p)
+			pipes.Stderr.Close()
+			wg.Done()
+		}()
+	}
+	return &cio{
+		config:  fifos.Config,
+		wg:      wg,
+		closers: append(pipes.closers(), fifos),
+		cancel: func() {
+			cancel()
+			for _, c := range pipes.closers() {
+				if c != nil {
+					c.Close()
+				}
+			}
+		},
+	}, nil
+}
+
+func openFifos(ctx context.Context, fifos *FIFOSet) (f pipes, retErr error) {
+	defer func() {
+		if retErr != nil {
+			fifos.Close()
+		}
+	}()
+
+	if fifos.Stdin != "" {
+		if f.Stdin, retErr = fifo.OpenFifo(ctx, fifos.Stdin, syscall.O_WRONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, fmt.Errorf("failed to open stdin fifo: %w", retErr)
+		}
+		defer func() {
+			if retErr != nil && f.Stdin != nil {
+				f.Stdin.Close()
+			}
+		}()
+	}
+	if fifos.Stdout != "" {
+		if f.Stdout, retErr = fifo.OpenFifo(ctx, fifos.Stdout, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, fmt.Errorf("failed to open stdout fifo: %w", retErr)
+		}
+		defer func() {
+			if retErr != nil && f.Stdout != nil {
+				f.Stdout.Close()
+			}
+		}()
+	}
+	if !fifos.Terminal && fifos.Stderr != "" {
+		if f.Stderr, retErr = fifo.OpenFifo(ctx, fifos.Stderr, syscall.O_RDONLY|syscall.O_CREAT|syscall.O_NONBLOCK, 0700); retErr != nil {
+			return f, fmt.Errorf("failed to open stderr fifo: %w", retErr)
+		}
+	}
+	return f, nil
+}
+
+// NewDirectIO returns an IO implementation that exposes the IO streams as io.ReadCloser
+// and io.WriteCloser.
+func NewDirectIO(ctx context.Context, fifos *FIFOSet) (*DirectIO, error) {
+	ctx, cancel := context.WithCancel(ctx)
+	pipes, err := openFifos(ctx, fifos)
+	return &DirectIO{
+		pipes: pipes,
+		cio: cio{
+			config:  fifos.Config,
+			closers: append(pipes.closers(), fifos),
+			cancel:  cancel,
+		},
+	}, err
+}