Function mountCgroupV1

libcontainer/rootfs_linux.go:326–397

(m mountEntry, c *mountConfig)

}

func mountCgroupV1(m mountEntry, c *mountConfig) error {
	binds, err := getCgroupMounts(m.Mount)
	if err != nil {
		return err
	}
	var merged []string
	for _, b := range binds {
		ss := filepath.Base(b.Destination)
		if strings.Contains(ss, ",") {
			merged = append(merged, ss)
		}
	}
	tmpfs := &configs.Mount{
		Source:           "tmpfs",
		Device:           "tmpfs",
		Destination:      m.Destination,
		Flags:            defaultMountFlags,
		Data:             "mode=755",
		PropagationFlags: m.PropagationFlags,
	}

	if err := mountToRootfs(c, mountEntry{Mount: tmpfs}); err != nil {
		return err
	}

	for _, b := range binds {
		if c.cgroupns {
			// We just created the tmpfs, and so we can just use filepath.Join
			// here (not to mention we want to make sure we create the path
			// inside the tmpfs, so we don't want to resolve symlinks).
			subsystemName := filepath.Base(b.Destination)
			subsystemDir, err := pathrs.MkdirAllInRoot(c.root, b.Destination, 0o755)
			if err != nil {
				return err
			}
			defer subsystemDir.Close()
			if err := utils.WithProcfdFile(subsystemDir, func(dstFd string) error {
				flags := defaultMountFlags
				if m.Flags&unix.MS_RDONLY != 0 {
					flags = flags | unix.MS_RDONLY
				}
				var (
					source = "cgroup"
					data   = subsystemName
				)
				if data == "systemd" {
					data = cgroups.CgroupNamePrefix + data
					source = "systemd"
				}
				return mountViaFds(source, nil, b.Destination, dstFd, "cgroup", uintptr(flags), data)
			}); err != nil {
				return err
			}
		} else {
			if err := mountToRootfs(c, mountEntry{Mount: b}); err != nil {
				return err
			}
		}