From f86c35a51ff92718e36ff6075339300be11e09b3 Mon Sep 17 00:00:00 2001
From: Michael Pratt <mpratt@google.com>
Date: Mon, 22 Apr 2019 18:17:25 -0700
Subject: Clean up state error handling

PiperOrigin-RevId: 244773836
Change-Id: I32223f79d2314fe1ac4ddfc63004fc22ff634adf
---
 pkg/sentry/control/state.go |  2 +-
 pkg/sentry/kernel/kernel.go | 23 ++++++++++++-----------
 pkg/state/state.go          | 20 +++++++++++++++-----
 3 files changed, 28 insertions(+), 17 deletions(-)

(limited to 'pkg')

diff --git a/pkg/sentry/control/state.go b/pkg/sentry/control/state.go
index 0a480c84a..b6bbf69fa 100644
--- a/pkg/sentry/control/state.go
+++ b/pkg/sentry/control/state.go
@@ -64,7 +64,7 @@ func (s *State) Save(o *SaveOpts, _ *struct{}) error {
 				log.Infof("Save succeeded: exiting...")
 			} else {
 				log.Warningf("Save failed: exiting...")
-				s.Kernel.SetExitError(err)
+				s.Kernel.SetSaveError(err)
 			}
 			s.Kernel.Kill(kernel.ExitStatus{})
 		},
diff --git a/pkg/sentry/kernel/kernel.go b/pkg/sentry/kernel/kernel.go
index 290c4a53c..ee6334509 100644
--- a/pkg/sentry/kernel/kernel.go
+++ b/pkg/sentry/kernel/kernel.go
@@ -175,9 +175,9 @@ type Kernel struct {
 	// netlinkPorts manages allocation of netlink socket port IDs.
 	netlinkPorts *port.Manager
 
-	// exitErr is the error causing the sandbox to exit, if any. It is
-	// protected by extMu.
-	exitErr error `state:"nosave"`
+	// saveErr is the error causing the sandbox to exit during save, if
+	// any. It is protected by extMu.
+	saveErr error `state:"nosave"`
 
 	// danglingEndpoints is used to save / restore tcpip.DanglingEndpoints.
 	danglingEndpoints struct{} `state:".([]tcpip.Endpoint)"`
@@ -1029,20 +1029,21 @@ func (k *Kernel) NetlinkPorts() *port.Manager {
 	return k.netlinkPorts
 }
 
-// ExitError returns the sandbox error that caused the kernel to exit.
-func (k *Kernel) ExitError() error {
+// SaveError returns the sandbox error that caused the kernel to exit during
+// save.
+func (k *Kernel) SaveError() error {
 	k.extMu.Lock()
 	defer k.extMu.Unlock()
-	return k.exitErr
+	return k.saveErr
 }
 
-// SetExitError sets the sandbox error that caused the kernel to exit, if one is
-// not already set.
-func (k *Kernel) SetExitError(err error) {
+// SetSaveError sets the sandbox error that caused the kernel to exit during
+// save, if one is not already set.
+func (k *Kernel) SetSaveError(err error) {
 	k.extMu.Lock()
 	defer k.extMu.Unlock()
-	if k.exitErr == nil {
-		k.exitErr = err
+	if k.saveErr == nil {
+		k.saveErr = err
 	}
 }
 
diff --git a/pkg/state/state.go b/pkg/state/state.go
index 4b141777e..4486f83a7 100644
--- a/pkg/state/state.go
+++ b/pkg/state/state.go
@@ -60,8 +60,8 @@ import (
 
 // ErrState is returned when an error is encountered during encode/decode.
 type ErrState struct {
-	// Err is the underlying error.
-	Err error
+	// err is the underlying error.
+	err error
 
 	// path is the visit path from root to the current object.
 	path string
@@ -72,7 +72,17 @@ type ErrState struct {
 
 // Error returns a sensible description of the state error.
 func (e *ErrState) Error() string {
-	return fmt.Sprintf("%v:\nstate path: %s\n%s", e.Err, e.path, e.trace)
+	return fmt.Sprintf("%v:\nstate path: %s\n%s", e.err, e.path, e.trace)
+}
+
+// UnwrapErrState returns the underlying error in ErrState.
+//
+// If err is not *ErrState, err is returned directly.
+func UnwrapErrState(err error) error {
+	if e, ok := err.(*ErrState); ok {
+		return e.err
+	}
+	return err
 }
 
 // Save saves the given object state.
@@ -318,9 +328,9 @@ func (sr *recoverable) safely(fn func()) (err error) {
 		if r := recover(); r != nil {
 			es := new(ErrState)
 			if e, ok := r.(error); ok {
-				es.Err = e
+				es.err = e
 			} else {
-				es.Err = fmt.Errorf("%v", r)
+				es.err = fmt.Errorf("%v", r)
 			}
 
 			es.path = sr.path()
-- 
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