1 files changed, 338 insertions, 0 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_time.go b/pkg/sentry/syscalls/linux/sys_time.go
new file mode 100644
index 000000000..dcee694b2
--- /dev/null
+++ b/pkg/sentry/syscalls/linux/sys_time.go
@@ -0,0 +1,338 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package linux
+
+import (
+	"time"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+	"gvisor.googlesource.com/gvisor/pkg/syserror"
+)
+
+// The most significant 29 bits hold either a pid or a file descriptor.
+func pidOfClockID(c int32) kernel.ThreadID {
+	return kernel.ThreadID(^(c >> 3))
+}
+
+// whichCPUClock returns one of CPUCLOCK_PERF, CPUCLOCK_VIRT, CPUCLOCK_SCHED or
+// CLOCK_FD.
+func whichCPUClock(c int32) int32 {
+	return c & linux.CPUCLOCK_CLOCK_MASK
+}
+
+// isCPUClockPerThread returns true if the CPUCLOCK_PERTHREAD bit is set in the
+// clock id.
+func isCPUClockPerThread(c int32) bool {
+	return c&linux.CPUCLOCK_PERTHREAD_MASK != 0
+}
+
+// isValidCPUClock returns checks that the cpu clock id is valid.
+func isValidCPUClock(c int32) bool {
+	// Bits 0, 1, and 2 cannot all be set.
+	if c&7 == 7 {
+		return false
+	}
+	if whichCPUClock(c) >= linux.CPUCLOCK_MAX {
+		return false
+	}
+	return true
+}
+
+// targetTask returns the kernel.Task for the given clock id.
+func targetTask(t *kernel.Task, c int32) *kernel.Task {
+	pid := pidOfClockID(c)
+	if pid == 0 {
+		return t
+	}
+	return t.PIDNamespace().TaskWithID(pid)
+}
+
+// ClockGetres implements linux syscall clock_getres(2).
+func ClockGetres(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	clockID := int32(args[0].Int())
+	addr := args[1].Pointer()
+	r := linux.Timespec{
+		Sec:  0,
+		Nsec: 1,
+	}
+
+	if _, err := getClock(t, clockID); err != nil {
+		return 0, nil, syserror.EINVAL
+	}
+
+	if addr == 0 {
+		// Don't need to copy out.
+		return 0, nil, nil
+	}
+
+	return 0, nil, copyTimespecOut(t, addr, &r)
+}
+
+type cpuClocker interface {
+	UserCPUClock() ktime.Clock
+	CPUClock() ktime.Clock
+}
+
+func getClock(t *kernel.Task, clockID int32) (ktime.Clock, error) {
+	if clockID < 0 {
+		if !isValidCPUClock(clockID) {
+			return nil, syserror.EINVAL
+		}
+
+		targetTask := targetTask(t, clockID)
+		if targetTask == nil {
+			return nil, syserror.EINVAL
+		}
+
+		var target cpuClocker
+		if isCPUClockPerThread(clockID) {
+			target = targetTask
+		} else {
+			target = targetTask.ThreadGroup()
+		}
+
+		switch whichCPUClock(clockID) {
+		case linux.CPUCLOCK_VIRT:
+			return target.UserCPUClock(), nil
+		case linux.CPUCLOCK_PROF, linux.CPUCLOCK_SCHED:
+			// CPUCLOCK_SCHED is approximated by CPUCLOCK_PROF.
+			return target.CPUClock(), nil
+		default:
+			return nil, syserror.EINVAL
+		}
+	}
+
+	switch clockID {
+	case linux.CLOCK_REALTIME, linux.CLOCK_REALTIME_COARSE:
+		return t.Kernel().RealtimeClock(), nil
+	case linux.CLOCK_MONOTONIC, linux.CLOCK_MONOTONIC_COARSE, linux.CLOCK_MONOTONIC_RAW:
+		// CLOCK_MONOTONIC approximates CLOCK_MONOTONIC_RAW.
+		return t.Kernel().MonotonicClock(), nil
+	case linux.CLOCK_PROCESS_CPUTIME_ID:
+		return t.ThreadGroup().CPUClock(), nil
+	case linux.CLOCK_THREAD_CPUTIME_ID:
+		return t.CPUClock(), nil
+	default:
+		return nil, syserror.EINVAL
+	}
+}
+
+// ClockGettime implements linux syscall clock_gettime(2).
+func ClockGettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	clockID := int32(args[0].Int())
+	addr := args[1].Pointer()
+
+	c, err := getClock(t, clockID)
+	if err != nil {
+		return 0, nil, err
+	}
+	ts := c.Now().Timespec()
+	return 0, nil, copyTimespecOut(t, addr, &ts)
+}
+
+// ClockSettime implements linux syscall clock_settime(2).
+func ClockSettime(*kernel.Task, arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	return 0, nil, syserror.EPERM
+}
+
+// Time implements linux syscall time(2).
+func Time(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	addr := args[0].Pointer()
+
+	r := t.Kernel().RealtimeClock().Now().TimeT()
+	if addr == usermem.Addr(0) {
+		return uintptr(r), nil, nil
+	}
+
+	if _, err := t.CopyOut(addr, r); err != nil {
+		return 0, nil, err
+	}
+	return uintptr(r), nil, nil
+}
+
+// clockNanosleepRestartBlock encapsulates the state required to restart
+// clock_nanosleep(2) via restart_syscall(2).
+type clockNanosleepRestartBlock struct {
+	c        ktime.Clock
+	duration time.Duration
+	rem      usermem.Addr
+}
+
+// Restart implements kernel.SyscallRestartBlock.Restart.
+func (n *clockNanosleepRestartBlock) Restart(t *kernel.Task) (uintptr, error) {
+	return 0, clockNanosleepFor(t, n.c, n.duration, n.rem)
+}
+
+// clockNanosleepUntil blocks until a specified time.
+//
+// If blocking is interrupted, the syscall is restarted with the original
+// arguments.
+func clockNanosleepUntil(t *kernel.Task, c ktime.Clock, ts linux.Timespec) error {
+	notifier, tchan := ktime.NewChannelNotifier()
+	timer := ktime.NewTimer(c, notifier)
+
+	// Turn on the timer.
+	timer.Swap(ktime.Setting{
+		Period:  0,
+		Enabled: true,
+		Next:    ktime.FromTimespec(ts),
+	})
+
+	err := t.BlockWithTimer(nil, tchan)
+
+	timer.Destroy()
+
+	// Did we just block until the timeout happened?
+	if err == syserror.ETIMEDOUT {
+		return nil
+	}
+
+	return syserror.ConvertIntr(err, kernel.ERESTARTNOHAND)
+}
+
+// clockNanosleepFor blocks for a specified duration.
+//
+// If blocking is interrupted, the syscall is restarted with the remaining
+// duration timeout.
+func clockNanosleepFor(t *kernel.Task, c ktime.Clock, dur time.Duration, rem usermem.Addr) error {
+	timer, start, tchan := ktime.After(c, dur)
+
+	err := t.BlockWithTimer(nil, tchan)
+
+	after := c.Now()
+
+	timer.Destroy()
+
+	var remaining time.Duration
+	// Did we just block for the entire duration?
+	if err == syserror.ETIMEDOUT {
+		remaining = 0
+	} else {
+		remaining = dur - after.Sub(start)
+		if remaining < 0 {
+			remaining = time.Duration(0)
+		}
+	}
+
+	// Copy out remaining time.
+	if err != nil && rem != usermem.Addr(0) {
+		timeleft := linux.NsecToTimespec(remaining.Nanoseconds())
+		if err := copyTimespecOut(t, rem, &timeleft); err != nil {
+			return err
+		}
+	}
+
+	// Did we just block for the entire duration?
+	if err == syserror.ETIMEDOUT {
+		return nil
+	}
+
+	// If interrupted, arrange for a restart with the remaining duration.
+	if err == syserror.ErrInterrupted {
+		t.SetSyscallRestartBlock(&clockNanosleepRestartBlock{
+			c:        c,
+			duration: remaining,
+			rem:      rem,
+		})
+		return kernel.ERESTART_RESTARTBLOCK
+	}
+
+	return err
+}
+
+// Nanosleep implements linux syscall Nanosleep(2).
+func Nanosleep(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	addr := args[0].Pointer()
+	rem := args[1].Pointer()
+
+	ts, err := copyTimespecIn(t, addr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	if !ts.Valid() {
+		return 0, nil, syserror.EINVAL
+	}
+
+	// Just like linux, we cap the timeout with the max number that int64 can
+	// represent which is roughly 292 years.
+	dur := time.Duration(ts.ToNsecCapped()) * time.Nanosecond
+	return 0, nil, clockNanosleepFor(t, t.Kernel().MonotonicClock(), dur, rem)
+}
+
+// ClockNanosleep implements linux syscall clock_nanosleep(2).
+func ClockNanosleep(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	clockID := int32(args[0].Int())
+	flags := args[1].Int()
+	addr := args[2].Pointer()
+	rem := args[3].Pointer()
+
+	req, err := copyTimespecIn(t, addr)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	if !req.Valid() {
+		return 0, nil, syserror.EINVAL
+	}
+
+	// Only allow clock constants also allowed by Linux.
+	if clockID > 0 {
+		if clockID != linux.CLOCK_REALTIME &&
+			clockID != linux.CLOCK_MONOTONIC &&
+			clockID != linux.CLOCK_PROCESS_CPUTIME_ID {
+			return 0, nil, syserror.EINVAL
+		}
+	}
+
+	c, err := getClock(t, clockID)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	if flags&linux.TIMER_ABSTIME != 0 {
+		return 0, nil, clockNanosleepUntil(t, c, req)
+	}
+
+	dur := time.Duration(req.ToNsecCapped()) * time.Nanosecond
+	return 0, nil, clockNanosleepFor(t, c, dur, rem)
+}
+
+// Gettimeofday implements linux syscall gettimeofday(2).
+func Gettimeofday(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	tv := args[0].Pointer()
+	tz := args[1].Pointer()
+
+	if tv != usermem.Addr(0) {
+		nowTv := t.Kernel().RealtimeClock().Now().Timeval()
+		if err := copyTimevalOut(t, tv, &nowTv); err != nil {
+			return 0, nil, err
+		}
+	}
+
+	if tz != usermem.Addr(0) {
+		// Ask the time package for the timezone.
+		_, offset := time.Now().Zone()
+		// This int32 array mimics linux's struct timezone.
+		timezone := [2]int32{-int32(offset) / 60, 0}
+		_, err := t.CopyOut(tz, timezone)
+		return 0, nil, err
+	}
+	return 0, nil, nil
+}