Move shim process code to package

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

linux/proc/process.go

@@ -0,0 +1,89 @@
+// +build !windows
+
+package proc
+
+import (
+	"context"
+	"io"
+	"sync"
+	"time"
+
+	"github.com/containerd/console"
+	"github.com/pkg/errors"
+)
+
+// RuncRoot is the path to the root runc state directory
+const RuncRoot = "/run/containerd/runc"
+
+// Stdio of a process
+type Stdio struct {
+	Stdin    string
+	Stdout   string
+	Stderr   string
+	Terminal bool
+}
+
+// IsNull returns true if the stdio is not defined
+func (s Stdio) IsNull() bool {
+	return s.Stdin == "" && s.Stdout == "" && s.Stderr == ""
+}
+
+// Process on a linux system
+type Process interface {
+	State
+	// ID returns the id for the process
+	ID() string
+	// Pid returns the pid for the process
+	Pid() int
+	// ExitStatus returns the exit status
+	ExitStatus() int
+	// ExitedAt is the time the process exited
+	ExitedAt() time.Time
+	// Stdin returns the process STDIN
+	Stdin() io.Closer
+	// Stdio returns io information for the container
+	Stdio() Stdio
+	// Status returns the process status
+	Status(context.Context) (string, error)
+	// Wait blocks until the process has exited
+	Wait()
+}
+
+// State of a process
+type State interface {
+	// Resize resizes the process console
+	Resize(ws console.WinSize) error
+	// Start execution of the process
+	Start(context.Context) error
+	// Delete deletes the process and its resourcess
+	Delete(context.Context) error
+	// Kill kills the process
+	Kill(context.Context, uint32, bool) error
+	// SetExited sets the exit status for the process
+	SetExited(status int)
+}
+
+func stateName(v interface{}) string {
+	switch v.(type) {
+	case *runningState, *execRunningState:
+		return "running"
+	case *createdState, *execCreatedState, *createdCheckpointState:
+		return "created"
+	case *pausedState:
+		return "paused"
+	case *deletedState:
+		return "deleted"
+	case *stoppedState:
+		return "stopped"
+	}
+	panic(errors.Errorf("invalid state %v", v))
+}
+
+// Platform handles platform-specific behavior that may differs across
+// platform implementations
+type Platform interface {
+	CopyConsole(ctx context.Context, console console.Console, stdin, stdout, stderr string,
+		wg, cwg *sync.WaitGroup) (console.Console, error)
+	ShutdownConsole(ctx context.Context, console console.Console) error
+	Close() error
+}