| 1 | //go:build linux |
| 2 | |
| 3 | package cgroup |
| 4 | |
| 5 | import ( |
| 6 | "errors" |
| 7 | |
| 8 | "github.com/carlosframework/platform/internal/controlname" |
| 9 | "golang.org/x/sys/unix" |
| 10 | ) |
| 11 | |
| 12 | type ContainmentIdentity struct{ Device, Inode uint64 } |
| 13 | |
| 14 | func (p *Prepared) Identity() (ContainmentIdentity, error) { |
| 15 | if p == nil || p.strictPreparedState == nil { |
| 16 | return ContainmentIdentity{}, ErrStrictState |
| 17 | } |
| 18 | p.mu.Lock() |
| 19 | defer p.mu.Unlock() |
| 20 | if err := p.identityOK(); err != nil { |
| 21 | return ContainmentIdentity{}, err |
| 22 | } |
| 23 | return ContainmentIdentity{Device: p.identity.device, Inode: p.identity.inode}, nil |
| 24 | } |
| 25 | |
| 26 | // PrepareRoleChild pins a newly empty role group below the host parent. It |
| 27 | // never reuses the parent's populated group and inherits its aggregate limits. |
| 28 | func (p *Prepared) PrepareRoleChild(role string) (*Prepared, error) { |
| 29 | return p.prepareRoleChild(role, nil) |
| 30 | } |
| 31 | |
| 32 | // PrepareRoleChildWithIntent requires a new name and persists the caller's |
| 33 | // intention under the pinned parent before mkdir. A failed preparation retains |
| 34 | // that intention for stop recovery; it never authorizes execution by itself. |
| 35 | func (p *Prepared) PrepareRoleChildWithIntent(role string, intent func(ContainmentIdentity) error) (*Prepared, error) { |
| 36 | if intent == nil { |
| 37 | return nil, ErrStrictRefused |
| 38 | } |
| 39 | return p.prepareRoleChild(role, intent) |
| 40 | } |
| 41 | |
| 42 | func (p *Prepared) prepareRoleChild(role string, intent func(ContainmentIdentity) error) (out *Prepared, err error) { |
| 43 | if p == nil || p.strictPreparedState == nil || !controlname.ValidLabel(role) { |
| 44 | return nil, ErrStrictRefused |
| 45 | } |
| 46 | p.mu.Lock() |
| 47 | defer p.mu.Unlock() |
| 48 | if p.parent != nil || p.empty || p.draining.Load() { |
| 49 | return nil, ErrStrictState |
| 50 | } |
| 51 | if err = p.identityOK(); err != nil { |
| 52 | return nil, err |
| 53 | } |
| 54 | name := "role-" + role |
| 55 | beforeMkdir := func() error { |
| 56 | if intent != nil { |
| 57 | var st unix.Stat_t |
| 58 | if e := unix.Fstatat(int(p.dir.Fd()), name, &st, unix.AT_SYMLINK_NOFOLLOW); !errors.Is(e, unix.ENOENT) { |
| 59 | return ErrStrictRefused |
| 60 | } |
| 61 | if e := intent(ContainmentIdentity{Device: p.identity.device, Inode: p.identity.inode}); e != nil { |
| 62 | return e |
| 63 | } |
| 64 | } |
| 65 | return nil |
| 66 | } |
| 67 | allowExisting := intent == nil |
| 68 | child, err := pinChild(p, name, beforeMkdir, allowExisting) |
| 69 | if err != nil { |
| 70 | return nil, err |
| 71 | } |
| 72 | return child, nil |
| 73 | } |
| 74 | |
amadan