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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 proc
import (
"fmt"
"io"
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/context"
"gvisor.dev/gvisor/pkg/errors/linuxerr"
"gvisor.dev/gvisor/pkg/sentry/fs"
"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
"gvisor.dev/gvisor/pkg/usermem"
"gvisor.dev/gvisor/pkg/waiter"
)
// LINT.IfChange
// uptime is a file containing the system uptime.
//
// +stateify savable
type uptime struct {
fsutil.SimpleFileInode
// The "start time" of the sandbox.
startTime ktime.Time
}
// newUptime returns a new uptime file.
func newUptime(ctx context.Context, msrc *fs.MountSource) *fs.Inode {
u := &uptime{
SimpleFileInode: *fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermsFromMode(0444), linux.PROC_SUPER_MAGIC),
startTime: ktime.NowFromContext(ctx),
}
return newProcInode(ctx, u, msrc, fs.SpecialFile, nil)
}
// GetFile implements fs.InodeOperations.GetFile.
func (u *uptime) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags) (*fs.File, error) {
return fs.NewFile(ctx, dirent, flags, &uptimeFile{startTime: u.startTime}), nil
}
// +stateify savable
type uptimeFile struct {
fsutil.FileGenericSeek `state:"nosave"`
fsutil.FileNoIoctl `state:"nosave"`
fsutil.FileNoMMap `state:"nosave"`
fsutil.FileNoSplice `state:"nosave"`
fsutil.FileNoWrite `state:"nosave"`
fsutil.FileNoopFlush `state:"nosave"`
fsutil.FileNoopFsync `state:"nosave"`
fsutil.FileNoopRelease `state:"nosave"`
fsutil.FileNotDirReaddir `state:"nosave"`
fsutil.FileUseInodeUnstableAttr `state:"nosave"`
waiter.AlwaysReady `state:"nosave"`
startTime ktime.Time
}
// Read implements fs.FileOperations.Read.
func (f *uptimeFile) Read(ctx context.Context, _ *fs.File, dst usermem.IOSequence, offset int64) (int64, error) {
if offset < 0 {
return 0, linuxerr.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(f.startTime).Seconds()))
if offset >= int64(len(s)) {
return 0, io.EOF
}
n, err := dst.CopyOut(ctx, s[offset:])
return int64(n), err
}
// LINT.ThenChange(../../fsimpl/proc/tasks_files.go)
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