Convert bind mounts to use DB field

Refactors creation of bind mounts into a separate function that
can be called from elsewhere (e.g. pod start or container
restart). This function stores the mounts in the DB using the
field established last commit.

Spec generation now relies upon this field in the DB instead of
manually enumerating files to be bind mounted in.

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

Closes: #462
Approved by: baude

1 files changed, 67 insertions, 44 deletions

diff --git a/libpod/container_internal.go b/libpod/container_internal.go
index 736655f13..3c7637717 100644
--- a/libpod/container_internal.go
+++ b/libpod/container_internal.go
@@ -162,6 +162,8 @@ func newContainer(rspec *spec.Spec, lockDir string) (*Container, error) {
 	ctr.config.ShmSize = DefaultShmSize
 	ctr.config.CgroupParent = DefaultCgroupParent
 
+	ctr.state.BindMounts = make(map[string]string)
+
 	// Path our lock file will reside at
 	lockPath := filepath.Join(lockDir, ctr.config.ID)
 	// Grab a lockfile at the given path
@@ -444,6 +446,56 @@ func (c *Container) cleanupStorage() error {
 	return c.save()
 }
 
+// Make standard bind mounts to include in the container
+func (c *Container) makeBindMounts() error {
+	if c.state.BindMounts == nil {
+		c.state.BindMounts = make(map[string]string)
+	}
+
+	// SHM is always added when we mount the container
+	c.state.BindMounts["/dev/shm"] = c.config.ShmDir
+
+	// Make /etc/resolv.conf
+	if path, ok := c.state.BindMounts["/etc/resolv.conf"]; ok {
+		// If it already exists, delete so we can recreate
+		if err := os.Remove(path); err != nil {
+			return errors.Wrapf(err, "error removing resolv.conf for container %s", c.ID())
+		}
+		delete(c.state.BindMounts, "/etc/resolv.conf")
+	}
+	newResolv, err := c.generateResolvConf()
+	if err != nil {
+		return errors.Wrapf(err, "error creating resolv.conf for container %s", c.ID())
+	}
+	c.state.BindMounts["/etc/resolv.conf"] = newResolv
+
+	// Make /etc/hosts
+	if path, ok := c.state.BindMounts["/etc/hosts"]; ok {
+		// If it already exists, delete so we can recreate
+		if err := os.Remove(path); err != nil {
+			return errors.Wrapf(err, "error removing hosts file for container %s", c.ID())
+		}
+		delete(c.state.BindMounts, "/etc/hosts")
+	}
+	newHosts, err := c.generateHosts()
+	if err != nil {
+		return errors.Wrapf(err, "error creating hosts file for container %s", c.ID())
+	}
+	c.state.BindMounts["/etc/hosts"] = newHosts
+
+	// Make /etc/hostname
+	// This should never change, so no need to recreate if it exists
+	if _, ok := c.state.BindMounts["/etc/hostname"]; !ok {
+		hostnamePath, err := c.writeStringToRundir("hostname", c.Hostname())
+		if err != nil {
+			return errors.Wrapf(err, "error creating hostname file for container %s", c.ID())
+		}
+		c.state.BindMounts["/etc/hostname"] = hostnamePath
+	}
+
+	return nil
+}
+
 // writeStringToRundir copies the provided file to the runtimedir
 func (c *Container) writeStringToRundir(destFile, output string) (string, error) {
 	destFileName := filepath.Join(c.state.RunDir, destFile)
@@ -579,58 +631,29 @@ func (c *Container) generateHosts() (string, error) {
 	return c.writeStringToRundir("hosts", hosts)
 }
 
-// generateEtcHostname creates a containers /etc/hostname
-func (c *Container) generateEtcHostname(hostname string) (string, error) {
-	return c.writeStringToRundir("hostname", hostname)
-}
-
 // Generate spec for a container
-func (c *Container) generateSpec(resolvPath, hostsPath, hostnamePath string) (*spec.Spec, error) {
+func (c *Container) generateSpec() (*spec.Spec, error) {
 	g := generate.NewFromSpec(c.config.Spec)
 
 	// If network namespace was requested, add it now
 	if c.config.CreateNetNS {
 		g.AddOrReplaceLinuxNamespace(spec.NetworkNamespace, c.state.NetNS.Path())
 	}
-	// Remove default /etc/shm mount
+
+	// Remove the default /dev/shm mount to ensure we overwrite it
 	g.RemoveMount("/dev/shm")
-	// Mount ShmDir from host into container
-	shmMnt := spec.Mount{
-		Type:        "bind",
-		Source:      c.config.ShmDir,
-		Destination: "/dev/shm",
-		Options:     []string{"rw", "bind"},
-	}
-	g.AddMount(shmMnt)
-	// Bind mount resolv.conf
-	resolvMnt := spec.Mount{
-		Type:        "bind",
-		Source:      resolvPath,
-		Destination: "/etc/resolv.conf",
-		Options:     []string{"rw", "bind"},
-	}
-	if !MountExists(g.Mounts(), resolvMnt.Destination) {
-		g.AddMount(resolvMnt)
-	}
-	// Bind mount hosts
-	hostsMnt := spec.Mount{
-		Type:        "bind",
-		Source:      hostsPath,
-		Destination: "/etc/hosts",
-		Options:     []string{"rw", "bind"},
-	}
-	if !MountExists(g.Mounts(), hostsMnt.Destination) {
-		g.AddMount(hostsMnt)
-	}
-	// Bind hostname
-	hostnameMnt := spec.Mount{
-		Type:        "bind",
-		Source:      hostnamePath,
-		Destination: "/etc/hostname",
-		Options:     []string{"rw", "bind"},
-	}
-	if !MountExists(g.Mounts(), hostnameMnt.Destination) {
-		g.AddMount(hostnameMnt)
+
+	// Add bind mounts to container
+	for dstPath, srcPath := range c.state.BindMounts {
+		newMount := spec.Mount{
+			Type:        "bind",
+			Source:      srcPath,
+			Destination: dstPath,
+			Options:     []string{"rw", "bind"},
+		}
+		if !MountExists(g.Mounts(), dstPath) {
+			g.AddMount(newMount)
+		}
 	}
 
 	// Bind builtin image volumes