containerd/containerd-shim/main.go
Michael Crosby 654c537d38 Call start in containerd
This fixes a sync issue when the containerd api returns after a
container has started.  It fixes it by calling the runtime start inside
containerd after the oom handler has been setup.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
2016-06-27 10:49:20 -07:00

153 lines
3.6 KiB
Go

package main
import (
"flag"
"fmt"
"io/ioutil"
"os"
"os/signal"
"path/filepath"
"syscall"
"github.com/docker/containerd/osutils"
"github.com/docker/docker/pkg/term"
)
func writeMessage(f *os.File, level string, err error) {
fmt.Fprintf(f, `{"level": "%s","msg": "%s"}`, level, err)
}
type controlMessage struct {
Type int
Width int
Height int
}
// containerd-shim is a small shim that sits in front of a runtime implementation
// that allows it to be repartented to init and handle reattach from the caller.
//
// the cwd of the shim should be the bundle for the container. Arg1 should be the path
// to the state directory where the shim can locate fifos and other information.
func main() {
flag.Parse()
cwd, err := os.Getwd()
if err != nil {
panic(err)
}
f, err := os.OpenFile(filepath.Join(cwd, "shim-log.json"), os.O_CREATE|os.O_WRONLY|os.O_APPEND|os.O_SYNC, 0666)
if err != nil {
panic(err)
}
if err := start(f); err != nil {
// this means that the runtime failed starting the container and will have the
// proper error messages in the runtime log so we should to treat this as a
// shim failure because the sim executed properly
if err == errRuntime {
f.Close()
return
}
// log the error instead of writing to stderr because the shim will have
// /dev/null as it's stdio because it is supposed to be reparented to system
// init and will not have anyone to read from it
writeMessage(f, "error", err)
f.Close()
os.Exit(1)
}
}
func start(log *os.File) error {
// start handling signals as soon as possible so that things are properly reaped
// or if runtime exits before we hit the handler
signals := make(chan os.Signal, 2048)
signal.Notify(signals)
// set the shim as the subreaper for all orphaned processes created by the container
if err := osutils.SetSubreaper(1); err != nil {
return err
}
// open the exit pipe
f, err := os.OpenFile("exit", syscall.O_WRONLY, 0)
if err != nil {
return err
}
defer f.Close()
control, err := os.OpenFile("control", syscall.O_RDWR, 0)
if err != nil {
return err
}
defer control.Close()
p, err := newProcess(flag.Arg(0), flag.Arg(1), flag.Arg(2))
if err != nil {
return err
}
defer func() {
if err := p.Close(); err != nil {
writeMessage(log, "warn", err)
}
}()
if err := p.create(); err != nil {
p.delete()
return err
}
msgC := make(chan controlMessage, 32)
go func() {
for {
var m controlMessage
if _, err := fmt.Fscanf(control, "%d %d %d\n", &m.Type, &m.Width, &m.Height); err != nil {
continue
}
msgC <- m
}
}()
var exitShim bool
for {
select {
case s := <-signals:
switch s {
case syscall.SIGCHLD:
exits, _ := osutils.Reap()
for _, e := range exits {
// check to see if runtime is one of the processes that has exited
if e.Pid == p.pid() {
exitShim = true
writeInt("exitStatus", e.Status)
}
}
}
// runtime has exited so the shim can also exit
if exitShim {
ioutil.WriteFile(fmt.Sprintf("/tmp/shim-delete-%d", p.pid()), []byte("deleting"), 0600)
p.delete()
p.Wait()
return nil
}
case msg := <-msgC:
switch msg.Type {
case 0:
// close stdin
if p.stdinCloser != nil {
p.stdinCloser.Close()
}
case 1:
if p.console == nil {
continue
}
ws := term.Winsize{
Width: uint16(msg.Width),
Height: uint16(msg.Height),
}
term.SetWinsize(p.console.Fd(), &ws)
}
}
}
return nil
}
func writeInt(path string, i int) error {
f, err := os.Create(path)
if err != nil {
return err
}
defer f.Close()
_, err = fmt.Fprintf(f, "%d", i)
return err
}