111 lines
2.6 KiB
Go
111 lines
2.6 KiB
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 shim
|
|
|
|
import (
|
|
"os/exec"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/containerd/containerd/sys"
|
|
runc "github.com/containerd/go-runc"
|
|
"github.com/pkg/errors"
|
|
)
|
|
|
|
// ErrNoSuchProcess is returned when the process no longer exists
|
|
var ErrNoSuchProcess = errors.New("no such process")
|
|
|
|
const bufferSize = 32
|
|
|
|
// Reap should be called when the process receives an SIGCHLD. Reap will reap
|
|
// all exited processes and close their wait channels
|
|
func Reap() error {
|
|
now := time.Now()
|
|
exits, err := sys.Reap(false)
|
|
Default.Lock()
|
|
for c := range Default.subscribers {
|
|
for _, e := range exits {
|
|
c <- runc.Exit{
|
|
Timestamp: now,
|
|
Pid: e.Pid,
|
|
Status: e.Status,
|
|
}
|
|
}
|
|
|
|
}
|
|
Default.Unlock()
|
|
return err
|
|
}
|
|
|
|
// Default is the default monitor initialized for the package
|
|
var Default = &Monitor{
|
|
subscribers: make(map[chan runc.Exit]struct{}),
|
|
}
|
|
|
|
// Monitor monitors the underlying system for process status changes
|
|
type Monitor struct {
|
|
sync.Mutex
|
|
|
|
subscribers map[chan runc.Exit]struct{}
|
|
}
|
|
|
|
// Start starts the command a registers the process with the reaper
|
|
func (m *Monitor) Start(c *exec.Cmd) (chan runc.Exit, error) {
|
|
ec := m.Subscribe()
|
|
if err := c.Start(); err != nil {
|
|
m.Unsubscribe(ec)
|
|
return nil, err
|
|
}
|
|
return ec, nil
|
|
}
|
|
|
|
// Wait blocks until a process is signal as dead.
|
|
// User should rely on the value of the exit status to determine if the
|
|
// command was successful or not.
|
|
func (m *Monitor) Wait(c *exec.Cmd, ec chan runc.Exit) (int, error) {
|
|
for e := range ec {
|
|
if e.Pid == c.Process.Pid {
|
|
// make sure we flush all IO
|
|
c.Wait()
|
|
m.Unsubscribe(ec)
|
|
return e.Status, nil
|
|
}
|
|
}
|
|
// return no such process if the ec channel is closed and no more exit
|
|
// events will be sent
|
|
return -1, ErrNoSuchProcess
|
|
}
|
|
|
|
// Subscribe to process exit changes
|
|
func (m *Monitor) Subscribe() chan runc.Exit {
|
|
c := make(chan runc.Exit, bufferSize)
|
|
m.Lock()
|
|
m.subscribers[c] = struct{}{}
|
|
m.Unlock()
|
|
return c
|
|
}
|
|
|
|
// Unsubscribe to process exit changes
|
|
func (m *Monitor) Unsubscribe(c chan runc.Exit) {
|
|
m.Lock()
|
|
delete(m.subscribers, c)
|
|
close(c)
|
|
m.Unlock()
|
|
}
|