// +build linux

/*
   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 runc

import (
	"context"
	"io/ioutil"
	"os"
	"path/filepath"
	"sync"

	"github.com/containerd/cgroups"
	"github.com/containerd/console"
	"github.com/containerd/containerd/errdefs"
	"github.com/containerd/containerd/mount"
	"github.com/containerd/containerd/namespaces"
	rproc "github.com/containerd/containerd/runtime/proc"
	"github.com/containerd/containerd/runtime/v1/linux/proc"
	"github.com/containerd/containerd/runtime/v2/runc/options"
	"github.com/containerd/containerd/runtime/v2/task"
	"github.com/containerd/typeurl"
	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

// NewContainer returns a new runc container
func NewContainer(ctx context.Context, platform rproc.Platform, r *task.CreateTaskRequest) (*Container, error) {
	ns, err := namespaces.NamespaceRequired(ctx)
	if err != nil {
		return nil, errors.Wrap(err, "create namespace")
	}

	var opts options.Options
	if r.Options != nil {
		v, err := typeurl.UnmarshalAny(r.Options)
		if err != nil {
			return nil, err
		}
		opts = *v.(*options.Options)
	}

	var mounts []proc.Mount
	for _, m := range r.Rootfs {
		mounts = append(mounts, proc.Mount{
			Type:    m.Type,
			Source:  m.Source,
			Target:  m.Target,
			Options: m.Options,
		})
	}

	rootfs := ""
	if len(mounts) > 0 {
		rootfs = filepath.Join(r.Bundle, "rootfs")
		if err := os.Mkdir(rootfs, 0711); err != nil && !os.IsExist(err) {
			return nil, err
		}
	}

	config := &proc.CreateConfig{
		ID:               r.ID,
		Bundle:           r.Bundle,
		Runtime:          opts.BinaryName,
		Rootfs:           mounts,
		Terminal:         r.Terminal,
		Stdin:            r.Stdin,
		Stdout:           r.Stdout,
		Stderr:           r.Stderr,
		Checkpoint:       r.Checkpoint,
		ParentCheckpoint: r.ParentCheckpoint,
		Options:          r.Options,
	}

	if err := WriteRuntime(r.Bundle, opts.BinaryName); err != nil {
		return nil, err
	}
	defer func() {
		if err != nil {
			if err2 := mount.UnmountAll(rootfs, 0); err2 != nil {
				logrus.WithError(err2).Warn("failed to cleanup rootfs mount")
			}
		}
	}()
	for _, rm := range mounts {
		m := &mount.Mount{
			Type:    rm.Type,
			Source:  rm.Source,
			Options: rm.Options,
		}
		if err := m.Mount(rootfs); err != nil {
			return nil, errors.Wrapf(err, "failed to mount rootfs component %v", m)
		}
	}

	process, err := newInit(
		ctx,
		r.Bundle,
		filepath.Join(r.Bundle, "work"),
		ns,
		platform,
		config,
		&opts,
		rootfs,
	)
	if err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	if err := process.Create(ctx, config); err != nil {
		return nil, errdefs.ToGRPC(err)
	}
	container := &Container{
		ID:        r.ID,
		Bundle:    r.Bundle,
		process:   process,
		processes: make(map[string]rproc.Process),
	}
	pid := process.Pid()
	if pid > 0 {
		cg, err := cgroups.Load(cgroups.V1, cgroups.PidPath(pid))
		if err != nil {
			logrus.WithError(err).Errorf("loading cgroup for %d", pid)
		}
		container.cgroup = cg
	}
	return container, nil
}

// ReadRuntime reads the runtime information from the path
func ReadRuntime(path string) (string, error) {
	data, err := ioutil.ReadFile(filepath.Join(path, "runtime"))
	if err != nil {
		return "", err
	}
	return string(data), nil
}

// WriteRuntime writes the runtime information into the path
func WriteRuntime(path, runtime string) error {
	return ioutil.WriteFile(filepath.Join(path, "runtime"), []byte(runtime), 0600)
}

func newInit(ctx context.Context, path, workDir, namespace string, platform rproc.Platform,
	r *proc.CreateConfig, options *options.Options, rootfs string) (*proc.Init, error) {
	runtime := proc.NewRunc(options.Root, path, namespace, options.BinaryName, options.CriuPath, options.SystemdCgroup)
	p := proc.New(r.ID, runtime, rproc.Stdio{
		Stdin:    r.Stdin,
		Stdout:   r.Stdout,
		Stderr:   r.Stderr,
		Terminal: r.Terminal,
	})
	p.Bundle = r.Bundle
	p.Platform = platform
	p.Rootfs = rootfs
	p.WorkDir = workDir
	p.IoUID = int(options.IoUid)
	p.IoGID = int(options.IoGid)
	p.NoPivotRoot = options.NoPivotRoot
	p.NoNewKeyring = options.NoNewKeyring
	p.CriuWorkPath = options.CriuWorkPath
	if p.CriuWorkPath == "" {
		// if criu work path not set, use container WorkDir
		p.CriuWorkPath = p.WorkDir
	}
	return p, nil
}

// Container for operating on a runc container and its processes
type Container struct {
	mu sync.Mutex

	// ID of the container
	ID string
	// Bundle path
	Bundle string

	cgroup    cgroups.Cgroup
	process   rproc.Process
	processes map[string]rproc.Process
}

// All processes in the container
func (c *Container) All() (o []rproc.Process) {
	c.mu.Lock()
	defer c.mu.Unlock()

	for _, p := range c.processes {
		o = append(o, p)
	}
	if c.process != nil {
		o = append(o, c.process)
	}
	return o
}

// ExecdProcesses added to the container
func (c *Container) ExecdProcesses() (o []rproc.Process) {
	c.mu.Lock()
	defer c.mu.Unlock()
	for _, p := range c.processes {
		o = append(o, p)
	}
	return o
}

// Pid of the main process of a container
func (c *Container) Pid() int {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.process.Pid()
}

// Cgroup of the container
func (c *Container) Cgroup() cgroups.Cgroup {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.cgroup
}

// CgroupSet sets the cgroup to the container
func (c *Container) CgroupSet(cg cgroups.Cgroup) {
	c.mu.Lock()
	c.cgroup = cg
	c.mu.Unlock()
}

// Process returns the process by id
func (c *Container) Process(id string) (rproc.Process, error) {
	c.mu.Lock()
	defer c.mu.Unlock()
	if id == "" {
		if c.process == nil {
			return nil, errors.Wrapf(errdefs.ErrFailedPrecondition, "container must be created")
		}
		return c.process, nil
	}
	p, ok := c.processes[id]
	if !ok {
		return nil, errors.Wrapf(errdefs.ErrNotFound, "process does not exist %s", id)
	}
	return p, nil
}

// ProcessExists returns true if the process by id exists
func (c *Container) ProcessExists(id string) bool {
	c.mu.Lock()
	defer c.mu.Unlock()
	_, ok := c.processes[id]
	return ok
}

// ProcessAdd adds a new process to the container
func (c *Container) ProcessAdd(process rproc.Process) {
	c.mu.Lock()
	defer c.mu.Unlock()
	c.processes[process.ID()] = process
}

// ProcessRemove removes the process by id from the container
func (c *Container) ProcessRemove(id string) {
	c.mu.Lock()
	defer c.mu.Unlock()
	delete(c.processes, id)
}

// Start a container process
func (c *Container) Start(ctx context.Context, r *task.StartRequest) (rproc.Process, error) {
	p, err := c.Process(r.ExecID)
	if err != nil {
		return nil, err
	}
	if err := p.Start(ctx); err != nil {
		return nil, err
	}
	if c.Cgroup() == nil && p.Pid() > 0 {
		cg, err := cgroups.Load(cgroups.V1, cgroups.PidPath(p.Pid()))
		if err != nil {
			logrus.WithError(err).Errorf("loading cgroup for %d", p.Pid())
		}
		c.cgroup = cg
	}
	return p, nil
}

// Delete the container or a process by id
func (c *Container) Delete(ctx context.Context, r *task.DeleteRequest) (rproc.Process, error) {
	p, err := c.Process(r.ExecID)
	if err != nil {
		return nil, err
	}
	if err := p.Delete(ctx); err != nil {
		return nil, err
	}
	if r.ExecID != "" {
		c.ProcessRemove(r.ExecID)
	}
	return p, nil
}

// Exec an additional process
func (c *Container) Exec(ctx context.Context, r *task.ExecProcessRequest) (rproc.Process, error) {
	process, err := c.process.(*proc.Init).Exec(ctx, c.Bundle, &proc.ExecConfig{
		ID:       r.ExecID,
		Terminal: r.Terminal,
		Stdin:    r.Stdin,
		Stdout:   r.Stdout,
		Stderr:   r.Stderr,
		Spec:     r.Spec,
	})
	if err != nil {
		return nil, err
	}
	c.ProcessAdd(process)
	return process, nil
}

// Pause the container
func (c *Container) Pause(ctx context.Context) error {
	return c.process.(*proc.Init).Pause(ctx)
}

// Resume the container
func (c *Container) Resume(ctx context.Context) error {
	return c.process.(*proc.Init).Resume(ctx)
}

// ResizePty of a process
func (c *Container) ResizePty(ctx context.Context, r *task.ResizePtyRequest) error {
	p, err := c.Process(r.ExecID)
	if err != nil {
		return err
	}
	ws := console.WinSize{
		Width:  uint16(r.Width),
		Height: uint16(r.Height),
	}
	return p.Resize(ws)
}

// Kill a process
func (c *Container) Kill(ctx context.Context, r *task.KillRequest) error {
	p, err := c.Process(r.ExecID)
	if err != nil {
		return err
	}
	return p.Kill(ctx, r.Signal, r.All)
}

// CloseIO of a process
func (c *Container) CloseIO(ctx context.Context, r *task.CloseIORequest) error {
	p, err := c.Process(r.ExecID)
	if err != nil {
		return err
	}
	if stdin := p.Stdin(); stdin != nil {
		if err := stdin.Close(); err != nil {
			return errors.Wrap(err, "close stdin")
		}
	}
	return nil
}

// Checkpoint the container
func (c *Container) Checkpoint(ctx context.Context, r *task.CheckpointTaskRequest) error {
	p, err := c.Process("")
	if err != nil {
		return err
	}
	var opts options.CheckpointOptions
	if r.Options != nil {
		v, err := typeurl.UnmarshalAny(r.Options)
		if err != nil {
			return err
		}
		opts = *v.(*options.CheckpointOptions)
	}
	return p.(*proc.Init).Checkpoint(ctx, &proc.CheckpointConfig{
		Path:                     r.Path,
		Exit:                     opts.Exit,
		AllowOpenTCP:             opts.OpenTcp,
		AllowExternalUnixSockets: opts.ExternalUnixSockets,
		AllowTerminal:            opts.Terminal,
		FileLocks:                opts.FileLocks,
		EmptyNamespaces:          opts.EmptyNamespaces,
		WorkDir:                  opts.WorkPath,
	})
}

// Update the resource information of a running container
func (c *Container) Update(ctx context.Context, r *task.UpdateTaskRequest) error {
	p, err := c.Process("")
	if err != nil {
		return err
	}
	return p.(*proc.Init).Update(ctx, r.Resources)
}

// HasPid returns true if the container owns a specific pid
func (c *Container) HasPid(pid int) bool {
	if c.Pid() == pid {
		return true
	}
	for _, p := range c.All() {
		if p.Pid() == pid {
			return true
		}
	}
	return false
}