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authorFabricio Voznika <fvoznika@google.com>2019-02-25 19:20:52 -0800
committerShentubot <shentubot@google.com>2019-02-25 19:21:47 -0800
commit52a2abfca43cffdb9cafb91a4266dacf51525470 (patch)
tree9a20ef60a4ecaf232749e5d22408c5c2d3de765f /runsc/cgroup
parent563c9ed1d6814776aa22d3a272fe55c15143fe79 (diff)
Fix cgroup when path is relative
This can happen when 'docker run --cgroup-parent=' flag is set. PiperOrigin-RevId: 235645559 Change-Id: Ieea3ae66939abadab621053551bf7d62d412e7ee
Diffstat (limited to 'runsc/cgroup')
-rw-r--r--runsc/cgroup/cgroup.go86
1 files changed, 59 insertions, 27 deletions
diff --git a/runsc/cgroup/cgroup.go b/runsc/cgroup/cgroup.go
index 87f051e79..2b338b6c6 100644
--- a/runsc/cgroup/cgroup.go
+++ b/runsc/cgroup/cgroup.go
@@ -161,20 +161,59 @@ func countCpuset(cpuset string) (int, error) {
return count, nil
}
+// LoadPaths loads cgroup paths for given 'pid', may be set to 'self'.
+func LoadPaths(pid string) (map[string]string, error) {
+ f, err := os.Open(filepath.Join("/proc", pid, "cgroup"))
+ if err != nil {
+ return nil, err
+ }
+ defer f.Close()
+
+ paths := make(map[string]string)
+ scanner := bufio.NewScanner(f)
+ for scanner.Scan() {
+ // Format: ID:controller1,controller2:path
+ // Example: 2:cpu,cpuacct:/user.slice
+ tokens := strings.Split(scanner.Text(), ":")
+ if len(tokens) != 3 {
+ return nil, fmt.Errorf("invalid cgroups file, line: %q", scanner.Text())
+ }
+ for _, ctrlr := range strings.Split(tokens[1], ",") {
+ paths[ctrlr] = tokens[2]
+ }
+ }
+ if err := scanner.Err(); err != nil {
+ return nil, err
+ }
+ return paths, nil
+}
+
// Cgroup represents a group inside all controllers. For example: Name='/foo/bar'
// maps to /sys/fs/cgroup/<controller>/foo/bar on all controllers.
type Cgroup struct {
- Name string `json:"name"`
- Own bool `json:"own"`
+ Name string `json:"name"`
+ Parents map[string]string `json:"parents"`
+ Own bool `json:"own"`
}
// New creates a new Cgroup instance if the spec includes a cgroup path.
// Returns nil otherwise.
-func New(spec *specs.Spec) *Cgroup {
+func New(spec *specs.Spec) (*Cgroup, error) {
if spec.Linux == nil || spec.Linux.CgroupsPath == "" {
- return nil
+ return nil, nil
+ }
+ var parents map[string]string
+ if !filepath.IsAbs(spec.Linux.CgroupsPath) {
+ var err error
+ parents, err = LoadPaths("self")
+ if err != nil {
+ return nil, fmt.Errorf("finding current cgroups: %v", err)
+ }
}
- return &Cgroup{Name: spec.Linux.CgroupsPath}
+ return &Cgroup{
+ Name: spec.Linux.CgroupsPath,
+ Parents: parents,
+ }, nil
}
// Install creates and configures cgroups according to 'res'. If cgroup path
@@ -188,9 +227,11 @@ func (c *Cgroup) Install(res *specs.LinuxResources) error {
return nil
}
- // Mark that cgroup resources are owned by me.
log.Debugf("Creating cgroup %q", c.Name)
+
+ // Mark that cgroup resources are owned by me.
c.Own = true
+
// The Cleanup object cleans up partially created cgroups when an error occurs.
// Errors occuring during cleanup itself are ignored.
clean := specutils.MakeCleanup(func() { _ = c.Uninstall() })
@@ -247,32 +288,19 @@ func (c *Cgroup) Uninstall() error {
func (c *Cgroup) Join() (func(), error) {
// First save the current state so it can be restored.
undo := func() {}
- f, err := os.Open("/proc/self/cgroup")
+ paths, err := LoadPaths("self")
if err != nil {
return undo, err
}
- defer f.Close()
-
var undoPaths []string
- scanner := bufio.NewScanner(f)
- for scanner.Scan() {
- // Format: ID:controller1,controller2:path
- // Example: 2:cpu,cpuacct:/user.slice
- tokens := strings.Split(scanner.Text(), ":")
- if len(tokens) != 3 {
- return undo, fmt.Errorf("formatting cgroups file, line: %q", scanner.Text())
- }
- for _, ctrlr := range strings.Split(tokens[1], ",") {
- // Skip controllers we don't handle.
- if _, ok := controllers[ctrlr]; ok {
- undoPaths = append(undoPaths, filepath.Join(cgroupRoot, ctrlr, tokens[2]))
- break
- }
+ for ctrlr, path := range paths {
+ // Skip controllers we don't handle.
+ if _, ok := controllers[ctrlr]; ok {
+ fullPath := filepath.Join(cgroupRoot, ctrlr, path)
+ undoPaths = append(undoPaths, fullPath)
+ break
}
}
- if err := scanner.Err(); err != nil {
- return undo, err
- }
// Replace empty undo with the real thing before changes are made to cgroups.
undo = func() {
@@ -316,7 +344,11 @@ func (c *Cgroup) MemoryLimit() (uint64, error) {
}
func (c *Cgroup) makePath(controllerName string) string {
- return filepath.Join(cgroupRoot, controllerName, c.Name)
+ path := c.Name
+ if parent, ok := c.Parents[controllerName]; ok {
+ path = filepath.Join(parent, c.Name)
+ }
+ return filepath.Join(cgroupRoot, controllerName, path)
}
type controller interface {