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// Copyright 2019 The Prometheus 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 procfs
import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"strings"
"github.com/prometheus/procfs/internal/util"
)
// A NetSockstat contains the output of /proc/net/sockstat{,6} for IPv4 or IPv6,
// respectively.
type NetSockstat struct {
// Used is non-nil for IPv4 sockstat results, but nil for IPv6.
Used *int
Protocols []NetSockstatProtocol
}
// A NetSockstatProtocol contains statistics about a given socket protocol.
// Pointer fields indicate that the value may or may not be present on any
// given protocol.
type NetSockstatProtocol struct {
Protocol string
InUse int
Orphan *int
TW *int
Alloc *int
Mem *int
Memory *int
}
// NetSockstat retrieves IPv4 socket statistics.
func (fs FS) NetSockstat() (*NetSockstat, error) {
return readSockstat(fs.proc.Path("net", "sockstat"))
}
// NetSockstat6 retrieves IPv6 socket statistics.
//
// If IPv6 is disabled on this kernel, the returned error can be checked with
// os.IsNotExist.
func (fs FS) NetSockstat6() (*NetSockstat, error) {
return readSockstat(fs.proc.Path("net", "sockstat6"))
}
// readSockstat opens and parses a NetSockstat from the input file.
func readSockstat(name string) (*NetSockstat, error) {
// This file is small and can be read with one syscall.
b, err := util.ReadFileNoStat(name)
if err != nil {
// Do not wrap this error so the caller can detect os.IsNotExist and
// similar conditions.
return nil, err
}
stat, err := parseSockstat(bytes.NewReader(b))
if err != nil {
return nil, fmt.Errorf("failed to read sockstats from %q: %v", name, err)
}
return stat, nil
}
// parseSockstat reads the contents of a sockstat file and parses a NetSockstat.
func parseSockstat(r io.Reader) (*NetSockstat, error) {
var stat NetSockstat
s := bufio.NewScanner(r)
for s.Scan() {
// Expect a minimum of a protocol and one key/value pair.
fields := strings.Split(s.Text(), " ")
if len(fields) < 3 {
return nil, fmt.Errorf("malformed sockstat line: %q", s.Text())
}
// The remaining fields are key/value pairs.
kvs, err := parseSockstatKVs(fields[1:])
if err != nil {
return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %v", s.Text(), err)
}
// The first field is the protocol. We must trim its colon suffix.
proto := strings.TrimSuffix(fields[0], ":")
switch proto {
case "sockets":
// Special case: IPv4 has a sockets "used" key/value pair that we
// embed at the top level of the structure.
used := kvs["used"]
stat.Used = &used
default:
// Parse all other lines as individual protocols.
nsp := parseSockstatProtocol(kvs)
nsp.Protocol = proto
stat.Protocols = append(stat.Protocols, nsp)
}
}
if err := s.Err(); err != nil {
return nil, err
}
return &stat, nil
}
// parseSockstatKVs parses a string slice into a map of key/value pairs.
func parseSockstatKVs(kvs []string) (map[string]int, error) {
if len(kvs)%2 != 0 {
return nil, errors.New("odd number of fields in key/value pairs")
}
// Iterate two values at a time to gather key/value pairs.
out := make(map[string]int, len(kvs)/2)
for i := 0; i < len(kvs); i += 2 {
vp := util.NewValueParser(kvs[i+1])
out[kvs[i]] = vp.Int()
if err := vp.Err(); err != nil {
return nil, err
}
}
return out, nil
}
// parseSockstatProtocol parses a NetSockstatProtocol from the input kvs map.
func parseSockstatProtocol(kvs map[string]int) NetSockstatProtocol {
var nsp NetSockstatProtocol
for k, v := range kvs {
// Capture the range variable to ensure we get unique pointers for
// each of the optional fields.
v := v
switch k {
case "inuse":
nsp.InUse = v
case "orphan":
nsp.Orphan = &v
case "tw":
nsp.TW = &v
case "alloc":
nsp.Alloc = &v
case "mem":
nsp.Mem = &v
case "memory":
nsp.Memory = &v
}
}
return nsp
}
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