Refactor container FS setup

No change in functionaly. Added containerMounter object
to keep state while the mounts are processed. This will
help upcoming changes to share mounts per-pod.

PiperOrigin-RevId: 251350096

1 files changed, 31 insertions, 27 deletions

diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go
index 52dccc994..a997776f8 100644
--- a/runsc/boot/loader.go
+++ b/runsc/boot/loader.go
@@ -288,7 +288,7 @@ func New(args Args) (*Loader, error) {
 	}
 
 	// Create a watchdog.
-	watchdog := watchdog.New(k, watchdog.DefaultTimeout, args.Conf.WatchdogAction)
+	dog := watchdog.New(k, watchdog.DefaultTimeout, args.Conf.WatchdogAction)
 
 	procArgs, err := newProcess(args.ID, args.Spec, creds, k)
 	if err != nil {
@@ -304,7 +304,7 @@ func New(args Args) (*Loader, error) {
 		k:            k,
 		conf:         args.Conf,
 		console:      args.Console,
-		watchdog:     watchdog,
+		watchdog:     dog,
 		spec:         args.Spec,
 		goferFDs:     args.GoferFDs,
 		stdioFDs:     args.StdioFDs,
@@ -486,17 +486,21 @@ func (l *Loader) run() error {
 	// If we are restoring, we do not want to create a process.
 	// l.restore is set by the container manager when a restore call is made.
 	if !l.restore {
-		if err := setupContainerFS(
-			&l.rootProcArgs,
-			l.spec,
-			l.conf,
-			l.stdioFDs,
-			l.goferFDs,
-			l.console,
-			l.rootProcArgs.Credentials,
-			l.rootProcArgs.Limits,
-			l.k,
-			"" /* CID, which isn't needed for the root container */); err != nil {
+		// Create the FD map, which will set stdin, stdout, and stderr.  If console
+		// is true, then ioctl calls will be passed through to the host fd.
+		ctx := l.rootProcArgs.NewContext(l.k)
+		fdm, err := createFDMap(ctx, l.rootProcArgs.Limits, l.console, l.stdioFDs)
+		if err != nil {
+			return fmt.Errorf("importing fds: %v", err)
+		}
+		// CreateProcess takes a reference on FDMap if successful. We won't need
+		// ours either way.
+		l.rootProcArgs.FDMap = fdm
+
+		// cid for root container can be empty. Only subcontainers need it to set
+		// the mount location.
+		mntr := newContainerMounter(l.spec, "", l.goferFDs, l.k)
+		if err := mntr.setupFS(ctx, l.conf, &l.rootProcArgs, l.rootProcArgs.Credentials); err != nil {
 			return err
 		}
 
@@ -552,7 +556,7 @@ func (l *Loader) createContainer(cid string) error {
 // startContainer starts a child container. It returns the thread group ID of
 // the newly created process. Caller owns 'files' and may close them after
 // this method returns.
-func (l *Loader) startContainer(k *kernel.Kernel, spec *specs.Spec, conf *Config, cid string, files []*os.File) error {
+func (l *Loader) startContainer(spec *specs.Spec, conf *Config, cid string, files []*os.File) error {
 	// Create capabilities.
 	caps, err := specutils.Capabilities(conf.EnableRaw, spec.Process.Capabilities)
 	if err != nil {
@@ -596,6 +600,16 @@ func (l *Loader) startContainer(k *kernel.Kernel, spec *specs.Spec, conf *Config
 		stdioFDs = append(stdioFDs, int(f.Fd()))
 	}
 
+	// Create the FD map, which will set stdin, stdout, and stderr.
+	ctx := procArgs.NewContext(l.k)
+	fdm, err := createFDMap(ctx, procArgs.Limits, false, stdioFDs)
+	if err != nil {
+		return fmt.Errorf("importing fds: %v", err)
+	}
+	// CreateProcess takes a reference on FDMap if successful. We won't need ours
+	// either way.
+	procArgs.FDMap = fdm
+
 	// Can't take ownership away from os.File. dup them to get a new FDs.
 	var goferFDs []int
 	for _, f := range files[3:] {
@@ -606,22 +620,12 @@ func (l *Loader) startContainer(k *kernel.Kernel, spec *specs.Spec, conf *Config
 		goferFDs = append(goferFDs, fd)
 	}
 
-	if err := setupContainerFS(
-		&procArgs,
-		spec,
-		conf,
-		stdioFDs,
-		goferFDs,
-		false,
-		creds,
-		procArgs.Limits,
-		k,
-		cid); err != nil {
+	mntr := newContainerMounter(spec, cid, goferFDs, l.k)
+	if err := mntr.setupFS(ctx, conf, &procArgs, creds); err != nil {
 		return fmt.Errorf("configuring container FS: %v", err)
 	}
 
-	ctx := procArgs.NewContext(l.k)
-	mns := k.RootMountNamespace()
+	mns := l.k.RootMountNamespace()
 	if err := setExecutablePath(ctx, mns, &procArgs); err != nil {
 		return fmt.Errorf("setting executable path for %+v: %v", procArgs, err)
 	}