// Copyright 2019 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 (
	"bytes"
	"fmt"

	"gvisor.dev/gvisor/pkg/sentry/context"
	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
)

// loadavgData backs /proc/loadavg.
//
// +stateify savable
type loadavgData struct {
	kernfs.DynamicBytesFile
}

var _ dynamicInode = (*loadavgData)(nil)

// Generate implements vfs.DynamicBytesSource.Generate.
func (d *loadavgData) Generate(ctx context.Context, buf *bytes.Buffer) error {
	// TODO(b/62345059): Include real data in fields.
	// Column 1-3: CPU and IO utilization of the last 1, 5, and 10 minute periods.
	// Column 4-5: currently running processes and the total number of processes.
	// Column 6: the last process ID used.
	fmt.Fprintf(buf, "%.2f %.2f %.2f %d/%d %d\n", 0.00, 0.00, 0.00, 0, 0, 0)
	return nil
}