cubefs

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// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package procfs
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import (
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	"bufio"
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	"bytes"
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	"errors"
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	"fmt"
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	"io"
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	"strings"
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	"github.com/prometheus/procfs/internal/util"
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)
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// A NetSockstat contains the output of /proc/net/sockstat{,6} for IPv4 or IPv6,
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// respectively.
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type NetSockstat struct {
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	// Used is non-nil for IPv4 sockstat results, but nil for IPv6.
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	Used      *int
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	Protocols []NetSockstatProtocol
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}
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// A NetSockstatProtocol contains statistics about a given socket protocol.
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// Pointer fields indicate that the value may or may not be present on any
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// given protocol.
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type NetSockstatProtocol struct {
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	Protocol string
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	InUse    int
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	Orphan   *int
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	TW       *int
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	Alloc    *int
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	Mem      *int
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	Memory   *int
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}
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// NetSockstat retrieves IPv4 socket statistics.
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func (fs FS) NetSockstat() (*NetSockstat, error) {
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	return readSockstat(fs.proc.Path("net", "sockstat"))
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}
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// NetSockstat6 retrieves IPv6 socket statistics.
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//
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// If IPv6 is disabled on this kernel, the returned error can be checked with
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// os.IsNotExist.
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func (fs FS) NetSockstat6() (*NetSockstat, error) {
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	return readSockstat(fs.proc.Path("net", "sockstat6"))
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}
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// readSockstat opens and parses a NetSockstat from the input file.
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func readSockstat(name string) (*NetSockstat, error) {
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	// This file is small and can be read with one syscall.
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	b, err := util.ReadFileNoStat(name)
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	if err != nil {
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		// Do not wrap this error so the caller can detect os.IsNotExist and
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		// similar conditions.
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		return nil, err
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	}
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	stat, err := parseSockstat(bytes.NewReader(b))
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	if err != nil {
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		return nil, fmt.Errorf("failed to read sockstats from %q: %w", name, err)
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	}
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	return stat, nil
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}
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// parseSockstat reads the contents of a sockstat file and parses a NetSockstat.
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func parseSockstat(r io.Reader) (*NetSockstat, error) {
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	var stat NetSockstat
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	s := bufio.NewScanner(r)
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	for s.Scan() {
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		// Expect a minimum of a protocol and one key/value pair.
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		fields := strings.Split(s.Text(), " ")
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		if len(fields) < 3 {
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			return nil, fmt.Errorf("malformed sockstat line: %q", s.Text())
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		}
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		// The remaining fields are key/value pairs.
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		kvs, err := parseSockstatKVs(fields[1:])
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		if err != nil {
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			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %w", s.Text(), err)
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		}
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		// The first field is the protocol. We must trim its colon suffix.
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		proto := strings.TrimSuffix(fields[0], ":")
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		switch proto {
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		case "sockets":
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			// Special case: IPv4 has a sockets "used" key/value pair that we
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			// embed at the top level of the structure.
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			used := kvs["used"]
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			stat.Used = &used
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		default:
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			// Parse all other lines as individual protocols.
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			nsp := parseSockstatProtocol(kvs)
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			nsp.Protocol = proto
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			stat.Protocols = append(stat.Protocols, nsp)
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		}
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	}
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	if err := s.Err(); err != nil {
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		return nil, err
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	}
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	return &stat, nil
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}
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// parseSockstatKVs parses a string slice into a map of key/value pairs.
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func parseSockstatKVs(kvs []string) (map[string]int, error) {
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	if len(kvs)%2 != 0 {
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		return nil, errors.New("odd number of fields in key/value pairs")
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	}
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	// Iterate two values at a time to gather key/value pairs.
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	out := make(map[string]int, len(kvs)/2)
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	for i := 0; i < len(kvs); i += 2 {
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		vp := util.NewValueParser(kvs[i+1])
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		out[kvs[i]] = vp.Int()
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		if err := vp.Err(); err != nil {
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			return nil, err
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		}
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	}
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	return out, nil
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}
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// parseSockstatProtocol parses a NetSockstatProtocol from the input kvs map.
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func parseSockstatProtocol(kvs map[string]int) NetSockstatProtocol {
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	var nsp NetSockstatProtocol
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	for k, v := range kvs {
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		// Capture the range variable to ensure we get unique pointers for
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		// each of the optional fields.
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		v := v
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		switch k {
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		case "inuse":
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			nsp.InUse = v
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		case "orphan":
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			nsp.Orphan = &v
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		case "tw":
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			nsp.TW = &v
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		case "alloc":
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			nsp.Alloc = &v
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		case "mem":
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			nsp.Mem = &v
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		case "memory":
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			nsp.Memory = &v
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		}
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	}
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	return nsp
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}
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