podman/cmd/podman/system/dial_stdio.go

146 lines
3.2 KiB
Go

package system
import (
"context"
"io"
"os"
"github.com/containers/podman/v4/cmd/podman/registry"
"github.com/containers/podman/v4/cmd/podman/validate"
"github.com/containers/podman/v4/pkg/bindings"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"github.com/spf13/cobra"
)
var (
dialStdioCommand = &cobra.Command{
Use: "dial-stdio",
Short: "Proxy the stdio stream to the daemon connection. Should not be invoked manually.",
Args: validate.NoArgs,
Hidden: true,
RunE: func(cmd *cobra.Command, args []string) error {
return runDialStdio()
},
Example: "podman system dial-stdio",
}
)
func init() {
registry.Commands = append(registry.Commands, registry.CliCommand{
Command: dialStdioCommand,
Parent: systemCmd,
})
}
func runDialStdio() error {
ctx := registry.Context()
cfg := registry.PodmanConfig()
ctx, cancel := context.WithCancel(ctx)
defer cancel()
bindCtx, err := bindings.NewConnection(ctx, cfg.URI)
if err != nil {
return errors.Wrap(err, "failed to open connection to podman")
}
conn, err := bindings.GetClient(bindCtx)
if err != nil {
return errors.Wrap(err, "failed to get connection after initialization")
}
netConn, err := conn.GetDialer(bindCtx)
if err != nil {
return errors.Wrap(err, "failed to open the raw stream connection")
}
defer netConn.Close()
var connHalfCloser halfCloser
switch t := netConn.(type) {
case halfCloser:
connHalfCloser = t
case halfReadWriteCloser:
connHalfCloser = &nopCloseReader{t}
default:
return errors.New("the raw stream connection does not implement halfCloser")
}
stdin2conn := make(chan error, 1)
conn2stdout := make(chan error, 1)
go func() {
stdin2conn <- copier(connHalfCloser, &halfReadCloserWrapper{os.Stdin}, "stdin to stream")
}()
go func() {
conn2stdout <- copier(&halfWriteCloserWrapper{os.Stdout}, connHalfCloser, "stream to stdout")
}()
select {
case err = <-stdin2conn:
if err != nil {
return err
}
// wait for stdout
err = <-conn2stdout
case err = <-conn2stdout:
// return immediately
}
return err
}
// Below portion taken from original docker CLI
// https://github.com/docker/cli/blob/v20.10.9/cli/command/system/dial_stdio.go
func copier(to halfWriteCloser, from halfReadCloser, debugDescription string) error {
defer func() {
if err := from.CloseRead(); err != nil {
logrus.Errorf("while CloseRead (%s): %v", debugDescription, err)
}
if err := to.CloseWrite(); err != nil {
logrus.Errorf("while CloseWrite (%s): %v", debugDescription, err)
}
}()
if _, err := io.Copy(to, from); err != nil {
return errors.Wrapf(err, "error while Copy (%s)", debugDescription)
}
return nil
}
type halfReadCloser interface {
io.Reader
CloseRead() error
}
type halfWriteCloser interface {
io.Writer
CloseWrite() error
}
type halfCloser interface {
halfReadCloser
halfWriteCloser
}
type halfReadWriteCloser interface {
io.Reader
halfWriteCloser
}
type nopCloseReader struct {
halfReadWriteCloser
}
func (x *nopCloseReader) CloseRead() error {
return nil
}
type halfReadCloserWrapper struct {
io.ReadCloser
}
func (x *halfReadCloserWrapper) CloseRead() error {
return x.Close()
}
type halfWriteCloserWrapper struct {
io.WriteCloser
}
func (x *halfWriteCloserWrapper) CloseWrite() error {
return x.Close()
}