diff options
author | Fabricio Voznika <fvoznika@google.com> | 2019-02-25 19:20:52 -0800 |
---|---|---|
committer | Shentubot <shentubot@google.com> | 2019-02-25 19:21:47 -0800 |
commit | 52a2abfca43cffdb9cafb91a4266dacf51525470 (patch) | |
tree | 9a20ef60a4ecaf232749e5d22408c5c2d3de765f /runsc/cgroup | |
parent | 563c9ed1d6814776aa22d3a272fe55c15143fe79 (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.go | 86 |
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 { |