// 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/kernel"
	"gvisor.dev/gvisor/pkg/sentry/vfs"
)

// mmapMinAddrData implements vfs.DynamicBytesSource for
// /proc/sys/vm/mmap_min_addr.
//
// +stateify savable
type mmapMinAddrData struct {
	k *kernel.Kernel
}

var _ vfs.DynamicBytesSource = (*mmapMinAddrData)(nil)

// Generate implements vfs.DynamicBytesSource.Generate.
func (d *mmapMinAddrData) Generate(ctx context.Context, buf *bytes.Buffer) error {
	fmt.Fprintf(buf, "%d\n", d.k.Platform.MinUserAddress())
	return nil
}

// +stateify savable
type overcommitMemory struct{}

var _ vfs.DynamicBytesSource = (*overcommitMemory)(nil)

// Generate implements vfs.DynamicBytesSource.Generate.
func (d *overcommitMemory) Generate(ctx context.Context, buf *bytes.Buffer) error {
	fmt.Fprintf(buf, "0\n")
	return nil
}