adding support for --bundle-dir -b to start, restore, and spec; fixes…

… issue #310

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

main.go

@@ -25,10 +25,11 @@ After creating config files for your root filesystem with runc, you can execute
 container in your shell by running:
 
     # cd /mycontainer
-    # runc start [ -c spec-config-file ] [ -r runtime-config-file ]
+    # runc start [-b bundle-dir] [-c spec-config-file] [-r runtime-config-file]
 
-If not specified, the default value for the 'spec-config-file' is 'config.json',
-and the default value for the 'runtime-config-file' is 'runtime.json'.`
+If not specified, the default value for the 'bundle-dir' is './', 
+'spec-config-file' is 'config.json', and the default value for the 
+'runtime-config-file' is 'runtime.json'.`
 )
 
 func main() {

restore.go

@@ -49,6 +49,11 @@ var restoreCommand = cli.Command{
 			Value: "",
 			Usage: "cgroups mode: 'soft' (default), 'full' and 'strict'.",
 		},
+		cli.StringFlag{
+			Name:  "bundle-dir, b",
+			Value: "./",
+			Usage: "path to the root of the bundle directory",
+		},
 		cli.StringFlag{
 			Name:  "config-file, c",
 			Value: "config.json",
@@ -65,6 +70,12 @@ var restoreCommand = cli.Command{
 		if imagePath == "" {
 			imagePath = getDefaultImagePath(context)
 		}
+		bundleDir := context.String("bundle-dir")
+		if bundleDir != "./" {
+			if err := os.Chdir(bundleDir); err != nil {
+				fatal(err)
+			}
+		}
 		spec, rspec, err := loadSpec(context.String("config-file"), context.String("runtime-file"))
 		if err != nil {
 			fatal(err)

spec.go

@@ -25,6 +25,11 @@ var specCommand = cli.Command{
 	Name:  "spec",
 	Usage: "create a new specification file",
 	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "bundle-dir, b",
+			Value: "./",
+			Usage: "path to the root of the bundle directory",
+		},
 		cli.StringFlag{
 			Name:  "config-file, c",
 			Value: "config.json",
@@ -247,6 +252,12 @@ var specCommand = cli.Command{
 			}
 			return nil
 		}
+		bundleDir := context.String("bundle-dir")
+		if bundleDir != "./" {
+			if err := os.Chdir(bundleDir); err != nil {
+				fatal(err)
+			}
+		}
 		cName := context.String("config-file")
 		rName := context.String("runtime-file")
 		if err := checkNoFile(cName); err != nil {

start.go

@@ -21,6 +21,11 @@ var startCommand = cli.Command{
 	Name:  "start",
 	Usage: "create and run a container",
 	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "bundle-dir, b",
+			Value: "./",
+			Usage: "path to the root of the bundle directory",
+		},
 		cli.StringFlag{
 			Name:  "config-file, c",
 			Value: "config.json",
@@ -33,6 +38,12 @@ var startCommand = cli.Command{
 		},
 	},
 	Action: func(context *cli.Context) {
+		bundleDir := context.String("bundle-dir")
+		if bundleDir != "./" {
+			if err := os.Chdir(bundleDir); err != nil {
+				fatal(err)
+			}
+		}
 		spec, rspec, err := loadSpec(context.String("config-file"), context.String("runtime-file"))
 		if err != nil {
 			fatal(err)