Fixed segfault in stats where container had netNS none or from container

Signed-off-by: haircommander <pehunt@redhat.com>

Closes: #1306
Approved by: rhatdan

2 files changed, 35 insertions, 3 deletions

diff --git a/libpod/networking_linux.go b/libpod/networking_linux.go
index e5f935e30..77ab97910 100644
--- a/libpod/networking_linux.go
+++ b/libpod/networking_linux.go
@@ -249,9 +249,35 @@ func (r *Runtime) teardownNetNS(ctr *Container) error {
 	return nil
 }
 
+func getContainerNetNS(ctr *Container) (string, error) {
+	if ctr.state.NetNS != nil {
+		return ctr.state.NetNS.Path(), nil
+	}
+	if ctr.config.NetNsCtr != "" {
+		c, err := ctr.runtime.GetContainer(ctr.config.NetNsCtr)
+		if err != nil {
+			return "", err
+		}
+		if err = c.syncContainer(); err != nil {
+			return "", err
+		}
+		return c.state.NetNS.Path(), nil
+	}
+	return "", nil
+}
+
 func getContainerNetIO(ctr *Container) (*netlink.LinkStatistics, error) {
 	var netStats *netlink.LinkStatistics
-	err := ns.WithNetNSPath(ctr.state.NetNS.Path(), func(_ ns.NetNS) error {
+	netNSPath, netPathErr := getContainerNetNS(ctr)
+	if netPathErr != nil {
+		return nil, netPathErr
+	}
+	if netNSPath == "" {
+		// If netNSPath is empty, it was set as none, and no netNS was set up
+		// this is a valid state and thus return no error, nor any statistics
+		return nil, nil
+	}
+	err := ns.WithNetNSPath(netNSPath, func(_ ns.NetNS) error {
 		link, err := netlink.LinkByName(ocicni.DefaultInterfaceName)
 		if err != nil {
 			return err
diff --git a/libpod/stats.go b/libpod/stats.go
index 7830919ba..61e85ed5e 100644
--- a/libpod/stats.go
+++ b/libpod/stats.go
@@ -66,8 +66,14 @@ func (c *Container) GetContainerStats(previousStats *ContainerStats) (*Container
 	stats.BlockInput, stats.BlockOutput = calculateBlockIO(cgroupStats)
 	stats.CPUNano = cgroupStats.CPU.Usage.Total
 	stats.SystemNano = cgroupStats.CPU.Usage.Kernel
-	stats.NetInput = netStats.TxBytes
-	stats.NetOutput = netStats.RxBytes
+	// Handle case where the container is not in a network namespace
+	if netStats != nil {
+		stats.NetInput = netStats.TxBytes
+		stats.NetOutput = netStats.RxBytes
+	} else {
+		stats.NetInput = 0
+		stats.NetOutput = 0
+	}
 
 	return stats, nil
 }