diff options
Diffstat (limited to 'pkg/sentry/syscalls/linux')
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_futex.go | 68 |
1 files changed, 65 insertions, 3 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_futex.go b/pkg/sentry/syscalls/linux/sys_futex.go index 7a1d396ec..f0c89cba4 100644 --- a/pkg/sentry/syscalls/linux/sys_futex.go +++ b/pkg/sentry/syscalls/linux/sys_futex.go @@ -124,6 +124,46 @@ func futexWaitDuration(t *kernel.Task, duration time.Duration, forever bool, add return 0, kernel.ERESTART_RESTARTBLOCK } +func futexLockPI(t *kernel.Task, ts linux.Timespec, forever bool, addr usermem.Addr, private bool) error { + w := t.FutexWaiter() + locked, err := t.Futex().LockPI(w, t, addr, uint32(t.ThreadID()), private, false) + if err != nil { + return err + } + if locked { + // Futex acquired, we're done! + return nil + } + + if forever { + err = t.Block(w.C) + } else { + notifier, tchan := ktime.NewChannelNotifier() + timer := ktime.NewTimer(t.Kernel().RealtimeClock(), notifier) + timer.Swap(ktime.Setting{ + Enabled: true, + Next: ktime.FromTimespec(ts), + }) + err = t.BlockWithTimer(w.C, tchan) + timer.Destroy() + } + + t.Futex().WaitComplete(w) + return syserror.ConvertIntr(err, kernel.ERESTARTSYS) +} + +func tryLockPI(t *kernel.Task, addr usermem.Addr, private bool) error { + w := t.FutexWaiter() + locked, err := t.Futex().LockPI(w, t, addr, uint32(t.ThreadID()), private, true) + if err != nil { + return err + } + if !locked { + return syserror.EWOULDBLOCK + } + return nil +} + // Futex implements linux syscall futex(2). // It provides a method for a program to wait for a value at a given address to // change, and a method to wake up anyone waiting on a particular address. @@ -144,7 +184,7 @@ func Futex(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall switch cmd { case linux.FUTEX_WAIT, linux.FUTEX_WAIT_BITSET: // WAIT{_BITSET} wait forever if the timeout isn't passed. - forever := timeout == 0 + forever := (timeout == 0) var timespec linux.Timespec if !forever { @@ -205,8 +245,30 @@ func Futex(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall n, err := t.Futex().WakeOp(t, addr, naddr, private, val, nreq, op) return uintptr(n), nil, err - case linux.FUTEX_LOCK_PI, linux.FUTEX_UNLOCK_PI, linux.FUTEX_TRYLOCK_PI, linux.FUTEX_WAIT_REQUEUE_PI, linux.FUTEX_CMP_REQUEUE_PI: - // We don't support any priority inversion futexes. + case linux.FUTEX_LOCK_PI: + forever := (timeout == 0) + + var timespec linux.Timespec + if !forever { + var err error + timespec, err = copyTimespecIn(t, timeout) + if err != nil { + return 0, nil, err + } + } + err := futexLockPI(t, timespec, forever, addr, private) + return 0, nil, err + + case linux.FUTEX_TRYLOCK_PI: + err := tryLockPI(t, addr, private) + return 0, nil, err + + case linux.FUTEX_UNLOCK_PI: + err := t.Futex().UnlockPI(t, addr, uint32(t.ThreadID()), private) + return 0, nil, err + + case linux.FUTEX_WAIT_REQUEUE_PI, linux.FUTEX_CMP_REQUEUE_PI: + t.Kernel().EmitUnimplementedEvent(t) return 0, nil, syserror.ENOSYS default: |