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// Copyright 2018 The gVisor Authors.
//
// 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.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/kernel"
"gvisor.dev/gvisor/pkg/syserror"
)
const nsecPerSec = int64(time.Second)
// Getitimer implements linux syscall getitimer(2).
func Getitimer(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
if t.Arch().Width() != 8 {
// Definition of linux.ItimerVal assumes 64-bit architecture.
return 0, nil, syserror.ENOSYS
}
timerID := args[0].Int()
addr := args[1].Pointer()
olditv, err := t.Getitimer(timerID)
if err != nil {
return 0, nil, err
}
// A NULL address is allowed, in which case no copy out takes place.
if addr == 0 {
return 0, nil, nil
}
_, err = olditv.CopyOut(t, addr)
return 0, nil, err
}
// Setitimer implements linux syscall setitimer(2).
func Setitimer(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
if t.Arch().Width() != 8 {
// Definition of linux.ItimerVal assumes 64-bit architecture.
return 0, nil, syserror.ENOSYS
}
timerID := args[0].Int()
newAddr := args[1].Pointer()
oldAddr := args[2].Pointer()
var newitv linux.ItimerVal
// A NULL address is allowed because because Linux allows
// setitimer(which, NULL, &old_value) which disables the timer. There is a
// KERN_WARN message saying this misfeature will be removed. However, that
// hasn't happened as of 3.19, so we continue to support it.
if newAddr != 0 {
if _, err := newitv.CopyIn(t, newAddr); err != nil {
return 0, nil, err
}
}
olditv, err := t.Setitimer(timerID, newitv)
if err != nil {
return 0, nil, err
}
// A NULL address is allowed, in which case no copy out takes place.
if oldAddr == 0 {
return 0, nil, nil
}
_, err = olditv.CopyOut(t, oldAddr)
return 0, nil, err
}
// Alarm implements linux syscall alarm(2).
func Alarm(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
duration := time.Duration(args[0].Uint()) * time.Second
olditv, err := t.Setitimer(linux.ITIMER_REAL, linux.ItimerVal{
Value: linux.DurationToTimeval(duration),
})
if err != nil {
return 0, nil, err
}
olddur := olditv.Value.ToDuration()
secs := olddur.Round(time.Second).Nanoseconds() / nsecPerSec
if secs == 0 && olddur != 0 {
// We can't return 0 if an alarm was previously scheduled.
secs = 1
}
return uintptr(secs), nil, nil
}
// TimerCreate implements linux syscall timer_create(2).
func TimerCreate(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
clockID := args[0].Int()
sevp := args[1].Pointer()
timerIDp := args[2].Pointer()
c, err := getClock(t, clockID)
if err != nil {
return 0, nil, err
}
var sev *linux.Sigevent
if sevp != 0 {
sev = &linux.Sigevent{}
if _, err = sev.CopyIn(t, sevp); err != nil {
return 0, nil, err
}
}
id, err := t.IntervalTimerCreate(c, sev)
if err != nil {
return 0, nil, err
}
if _, err := id.CopyOut(t, timerIDp); err != nil {
t.IntervalTimerDelete(id)
return 0, nil, err
}
return 0, nil, nil
}
// TimerSettime implements linux syscall timer_settime(2).
func TimerSettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
timerID := linux.TimerID(args[0].Value)
flags := args[1].Int()
newValAddr := args[2].Pointer()
oldValAddr := args[3].Pointer()
var newVal linux.Itimerspec
if _, err := newVal.CopyIn(t, newValAddr); err != nil {
return 0, nil, err
}
oldVal, err := t.IntervalTimerSettime(timerID, newVal, flags&linux.TIMER_ABSTIME != 0)
if err != nil {
return 0, nil, err
}
if oldValAddr != 0 {
_, err = oldVal.CopyOut(t, oldValAddr)
return 0, nil, err
}
return 0, nil, nil
}
// TimerGettime implements linux syscall timer_gettime(2).
func TimerGettime(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
timerID := linux.TimerID(args[0].Value)
curValAddr := args[1].Pointer()
curVal, err := t.IntervalTimerGettime(timerID)
if err != nil {
return 0, nil, err
}
_, err = curVal.CopyOut(t, curValAddr)
return 0, nil, err
}
// TimerGetoverrun implements linux syscall timer_getoverrun(2).
func TimerGetoverrun(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
timerID := linux.TimerID(args[0].Value)
o, err := t.IntervalTimerGetoverrun(timerID)
if err != nil {
return 0, nil, err
}
return uintptr(o), nil, nil
}
// TimerDelete implements linux syscall timer_delete(2).
func TimerDelete(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
timerID := linux.TimerID(args[0].Value)
return 0, nil, t.IntervalTimerDelete(timerID)
}
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