github.com/SagerNet/gvisor@v0.0.0-20210707092255-7731c139d75c/pkg/sentry/fs/proc/loadavg.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package proc
    16  
    17  import (
    18  	"bytes"
    19  	"fmt"
    20  
    21  	"github.com/SagerNet/gvisor/pkg/context"
    22  	"github.com/SagerNet/gvisor/pkg/sentry/fs/proc/seqfile"
    23  )
    24  
    25  // LINT.IfChange
    26  
    27  // loadavgData backs /proc/loadavg.
    28  //
    29  // +stateify savable
    30  type loadavgData struct{}
    31  
    32  // NeedsUpdate implements seqfile.SeqSource.NeedsUpdate.
    33  func (*loadavgData) NeedsUpdate(generation int64) bool {
    34  	return true
    35  }
    36  
    37  // ReadSeqFileData implements seqfile.SeqSource.ReadSeqFileData.
    38  func (d *loadavgData) ReadSeqFileData(ctx context.Context, h seqfile.SeqHandle) ([]seqfile.SeqData, int64) {
    39  	if h != nil {
    40  		return nil, 0
    41  	}
    42  
    43  	var buf bytes.Buffer
    44  
    45  	// TODO(b/62345059): Include real data in fields.
    46  	// Column 1-3: CPU and IO utilization of the last 1, 5, and 10 minute periods.
    47  	// Column 4-5: currently running processes and the total number of processes.
    48  	// Column 6: the last process ID used.
    49  	fmt.Fprintf(&buf, "%.2f %.2f %.2f %d/%d %d\n", 0.00, 0.00, 0.00, 0, 0, 0)
    50  
    51  	return []seqfile.SeqData{
    52  		{
    53  			Buf:    buf.Bytes(),
    54  			Handle: (*loadavgData)(nil),
    55  		},
    56  	}, 0
    57  }
    58  
    59  // LINT.ThenChange(../../fsimpl/proc/tasks_files.go)