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// 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 proc
import (
"fmt"
"io"
"gvisor.googlesource.com/gvisor/pkg/sentry/context"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
"gvisor.googlesource.com/gvisor/pkg/sentry/fs/ramfs"
ktime "gvisor.googlesource.com/gvisor/pkg/sentry/kernel/time"
"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
"gvisor.googlesource.com/gvisor/pkg/syserror"
)
// uptime is a file containing the system uptime.
type uptime struct {
ramfs.Entry
// The "start time" of the sandbox.
startTime ktime.Time
}
// newUptime returns a new uptime file.
func (p *proc) newUptime(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
u := &uptime{
startTime: ktime.NowFromContext(ctx),
}
u.InitEntry(ctx, fs.RootOwner, fs.FilePermsFromMode(0444))
return newFile(u, msrc, fs.SpecialFile, nil)
}
// DeprecatedPreadv reads the current uptime.
func (u *uptime) DeprecatedPreadv(ctx context.Context, dst usermem.IOSequence, offset int64) (int64, error) {
if offset < 0 {
return 0, syserror.EINVAL
}
now := ktime.NowFromContext(ctx)
// Pretend that we've spent zero time sleeping (second number).
s := []byte(fmt.Sprintf("%.2f 0.00\n", now.Sub(u.startTime).Seconds()))
if offset >= int64(len(s)) {
return 0, io.EOF
}
n, err := dst.CopyOut(ctx, s[offset:])
return int64(n), err
}
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