gotosocial/vendor/gopkg.in/mcuadros/go-syslog.v2/internal/syslogparser/rfc5424/rfc5424.go

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// Note to self : never try to code while looking after your kids
// The result might look like this : https://pbs.twimg.com/media/BXqSuYXIEAAscVA.png
package rfc5424
import (
"fmt"
"math"
"strconv"
"time"
"gopkg.in/mcuadros/go-syslog.v2/internal/syslogparser"
)
const (
NILVALUE = '-'
)
var (
ErrYearInvalid = &syslogparser.ParserError{"Invalid year in timestamp"}
ErrMonthInvalid = &syslogparser.ParserError{"Invalid month in timestamp"}
ErrDayInvalid = &syslogparser.ParserError{"Invalid day in timestamp"}
ErrHourInvalid = &syslogparser.ParserError{"Invalid hour in timestamp"}
ErrMinuteInvalid = &syslogparser.ParserError{"Invalid minute in timestamp"}
ErrSecondInvalid = &syslogparser.ParserError{"Invalid second in timestamp"}
ErrSecFracInvalid = &syslogparser.ParserError{"Invalid fraction of second in timestamp"}
ErrTimeZoneInvalid = &syslogparser.ParserError{"Invalid time zone in timestamp"}
ErrInvalidTimeFormat = &syslogparser.ParserError{"Invalid time format"}
ErrInvalidAppName = &syslogparser.ParserError{"Invalid app name"}
ErrInvalidProcId = &syslogparser.ParserError{"Invalid proc ID"}
ErrInvalidMsgId = &syslogparser.ParserError{"Invalid msg ID"}
ErrNoStructuredData = &syslogparser.ParserError{"No structured data"}
)
type Parser struct {
buff []byte
cursor int
l int
header header
structuredData string
message string
}
type header struct {
priority syslogparser.Priority
version int
timestamp time.Time
hostname string
appName string
procId string
msgId string
}
type partialTime struct {
hour int
minute int
seconds int
secFrac float64
}
type fullTime struct {
pt partialTime
loc *time.Location
}
type fullDate struct {
year int
month int
day int
}
func NewParser(buff []byte) *Parser {
return &Parser{
buff: buff,
cursor: 0,
l: len(buff),
}
}
func (p *Parser) Location(location *time.Location) {
// Ignore as RFC5424 syslog always has a timezone
}
func (p *Parser) Parse() error {
hdr, err := p.parseHeader()
if err != nil {
return err
}
p.header = hdr
sd, err := p.parseStructuredData()
if err != nil {
return err
}
p.structuredData = sd
p.cursor++
if p.cursor < p.l {
p.message = string(p.buff[p.cursor:])
}
return nil
}
func (p *Parser) Dump() syslogparser.LogParts {
return syslogparser.LogParts{
"priority": p.header.priority.P,
"facility": p.header.priority.F.Value,
"severity": p.header.priority.S.Value,
"version": p.header.version,
"timestamp": p.header.timestamp,
"hostname": p.header.hostname,
"app_name": p.header.appName,
"proc_id": p.header.procId,
"msg_id": p.header.msgId,
"structured_data": p.structuredData,
"message": p.message,
}
}
// HEADER = PRI VERSION SP TIMESTAMP SP HOSTNAME SP APP-NAME SP PROCID SP MSGID
func (p *Parser) parseHeader() (header, error) {
hdr := header{}
pri, err := p.parsePriority()
if err != nil {
return hdr, err
}
hdr.priority = pri
ver, err := p.parseVersion()
if err != nil {
return hdr, err
}
hdr.version = ver
p.cursor++
ts, err := p.parseTimestamp()
if err != nil {
return hdr, err
}
hdr.timestamp = ts
p.cursor++
host, err := p.parseHostname()
if err != nil {
return hdr, err
}
hdr.hostname = host
p.cursor++
appName, err := p.parseAppName()
if err != nil {
return hdr, err
}
hdr.appName = appName
p.cursor++
procId, err := p.parseProcId()
if err != nil {
return hdr, nil
}
hdr.procId = procId
p.cursor++
msgId, err := p.parseMsgId()
if err != nil {
return hdr, nil
}
hdr.msgId = msgId
p.cursor++
return hdr, nil
}
func (p *Parser) parsePriority() (syslogparser.Priority, error) {
return syslogparser.ParsePriority(p.buff, &p.cursor, p.l)
}
func (p *Parser) parseVersion() (int, error) {
return syslogparser.ParseVersion(p.buff, &p.cursor, p.l)
}
// https://tools.ietf.org/html/rfc5424#section-6.2.3
func (p *Parser) parseTimestamp() (time.Time, error) {
var ts time.Time
if p.cursor >= p.l {
return ts, ErrInvalidTimeFormat
}
if p.buff[p.cursor] == NILVALUE {
p.cursor++
return ts, nil
}
fd, err := parseFullDate(p.buff, &p.cursor, p.l)
if err != nil {
return ts, err
}
if p.cursor >= p.l || p.buff[p.cursor] != 'T' {
return ts, ErrInvalidTimeFormat
}
p.cursor++
ft, err := parseFullTime(p.buff, &p.cursor, p.l)
if err != nil {
return ts, syslogparser.ErrTimestampUnknownFormat
}
nSec, err := toNSec(ft.pt.secFrac)
if err != nil {
return ts, err
}
ts = time.Date(
fd.year,
time.Month(fd.month),
fd.day,
ft.pt.hour,
ft.pt.minute,
ft.pt.seconds,
nSec,
ft.loc,
)
return ts, nil
}
// HOSTNAME = NILVALUE / 1*255PRINTUSASCII
func (p *Parser) parseHostname() (string, error) {
return syslogparser.ParseHostname(p.buff, &p.cursor, p.l)
}
// APP-NAME = NILVALUE / 1*48PRINTUSASCII
func (p *Parser) parseAppName() (string, error) {
return parseUpToLen(p.buff, &p.cursor, p.l, 48, ErrInvalidAppName)
}
// PROCID = NILVALUE / 1*128PRINTUSASCII
func (p *Parser) parseProcId() (string, error) {
return parseUpToLen(p.buff, &p.cursor, p.l, 128, ErrInvalidProcId)
}
// MSGID = NILVALUE / 1*32PRINTUSASCII
func (p *Parser) parseMsgId() (string, error) {
return parseUpToLen(p.buff, &p.cursor, p.l, 32, ErrInvalidMsgId)
}
func (p *Parser) parseStructuredData() (string, error) {
return parseStructuredData(p.buff, &p.cursor, p.l)
}
// ----------------------------------------------
// https://tools.ietf.org/html/rfc5424#section-6
// ----------------------------------------------
// XXX : bind them to Parser ?
// FULL-DATE : DATE-FULLYEAR "-" DATE-MONTH "-" DATE-MDAY
func parseFullDate(buff []byte, cursor *int, l int) (fullDate, error) {
var fd fullDate
year, err := parseYear(buff, cursor, l)
if err != nil {
return fd, err
}
if *cursor >= l || buff[*cursor] != '-' {
return fd, syslogparser.ErrTimestampUnknownFormat
}
*cursor++
month, err := parseMonth(buff, cursor, l)
if err != nil {
return fd, err
}
if *cursor >= l || buff[*cursor] != '-' {
return fd, syslogparser.ErrTimestampUnknownFormat
}
*cursor++
day, err := parseDay(buff, cursor, l)
if err != nil {
return fd, err
}
fd = fullDate{
year: year,
month: month,
day: day,
}
return fd, nil
}
// DATE-FULLYEAR = 4DIGIT
func parseYear(buff []byte, cursor *int, l int) (int, error) {
yearLen := 4
if *cursor+yearLen > l {
return 0, syslogparser.ErrEOL
}
// XXX : we do not check for a valid year (ie. 1999, 2013 etc)
// XXX : we only checks the format is correct
sub := string(buff[*cursor : *cursor+yearLen])
*cursor += yearLen
year, err := strconv.Atoi(sub)
if err != nil {
return 0, ErrYearInvalid
}
return year, nil
}
// DATE-MONTH = 2DIGIT ; 01-12
func parseMonth(buff []byte, cursor *int, l int) (int, error) {
return syslogparser.Parse2Digits(buff, cursor, l, 1, 12, ErrMonthInvalid)
}
// DATE-MDAY = 2DIGIT ; 01-28, 01-29, 01-30, 01-31 based on month/year
func parseDay(buff []byte, cursor *int, l int) (int, error) {
// XXX : this is a relaxed constraint
// XXX : we do not check if valid regarding February or leap years
// XXX : we only checks that day is in range [01 -> 31]
// XXX : in other words this function will not rant if you provide Feb 31th
return syslogparser.Parse2Digits(buff, cursor, l, 1, 31, ErrDayInvalid)
}
// FULL-TIME = PARTIAL-TIME TIME-OFFSET
func parseFullTime(buff []byte, cursor *int, l int) (fullTime, error) {
var loc = new(time.Location)
var ft fullTime
pt, err := parsePartialTime(buff, cursor, l)
if err != nil {
return ft, err
}
loc, err = parseTimeOffset(buff, cursor, l)
if err != nil {
return ft, err
}
ft = fullTime{
pt: pt,
loc: loc,
}
return ft, nil
}
// PARTIAL-TIME = TIME-HOUR ":" TIME-MINUTE ":" TIME-SECOND[TIME-SECFRAC]
func parsePartialTime(buff []byte, cursor *int, l int) (partialTime, error) {
var pt partialTime
hour, minute, err := getHourMinute(buff, cursor, l)
if err != nil {
return pt, err
}
if *cursor >= l || buff[*cursor] != ':' {
return pt, ErrInvalidTimeFormat
}
*cursor++
// ----
seconds, err := parseSecond(buff, cursor, l)
if err != nil {
return pt, err
}
pt = partialTime{
hour: hour,
minute: minute,
seconds: seconds,
}
// ----
if *cursor >= l || buff[*cursor] != '.' {
return pt, nil
}
*cursor++
secFrac, err := parseSecFrac(buff, cursor, l)
if err != nil {
return pt, nil
}
pt.secFrac = secFrac
return pt, nil
}
// TIME-HOUR = 2DIGIT ; 00-23
func parseHour(buff []byte, cursor *int, l int) (int, error) {
return syslogparser.Parse2Digits(buff, cursor, l, 0, 23, ErrHourInvalid)
}
// TIME-MINUTE = 2DIGIT ; 00-59
func parseMinute(buff []byte, cursor *int, l int) (int, error) {
return syslogparser.Parse2Digits(buff, cursor, l, 0, 59, ErrMinuteInvalid)
}
// TIME-SECOND = 2DIGIT ; 00-59
func parseSecond(buff []byte, cursor *int, l int) (int, error) {
return syslogparser.Parse2Digits(buff, cursor, l, 0, 59, ErrSecondInvalid)
}
// TIME-SECFRAC = "." 1*6DIGIT
func parseSecFrac(buff []byte, cursor *int, l int) (float64, error) {
maxDigitLen := 6
max := *cursor + maxDigitLen
from := *cursor
to := from
for to = from; to < max; to++ {
if to >= l {
break
}
c := buff[to]
if !syslogparser.IsDigit(c) {
break
}
}
sub := string(buff[from:to])
if len(sub) == 0 {
return 0, ErrSecFracInvalid
}
secFrac, err := strconv.ParseFloat("0."+sub, 64)
*cursor = to
if err != nil {
return 0, ErrSecFracInvalid
}
return secFrac, nil
}
// TIME-OFFSET = "Z" / TIME-NUMOFFSET
func parseTimeOffset(buff []byte, cursor *int, l int) (*time.Location, error) {
if *cursor >= l || buff[*cursor] == 'Z' {
*cursor++
return time.UTC, nil
}
return parseNumericalTimeOffset(buff, cursor, l)
}
// TIME-NUMOFFSET = ("+" / "-") TIME-HOUR ":" TIME-MINUTE
func parseNumericalTimeOffset(buff []byte, cursor *int, l int) (*time.Location, error) {
var loc = new(time.Location)
sign := buff[*cursor]
if (sign != '+') && (sign != '-') {
return loc, ErrTimeZoneInvalid
}
*cursor++
hour, minute, err := getHourMinute(buff, cursor, l)
if err != nil {
return loc, err
}
tzStr := fmt.Sprintf("%s%02d:%02d", string(sign), hour, minute)
tmpTs, err := time.Parse("-07:00", tzStr)
if err != nil {
return loc, err
}
return tmpTs.Location(), nil
}
func getHourMinute(buff []byte, cursor *int, l int) (int, int, error) {
hour, err := parseHour(buff, cursor, l)
if err != nil {
return 0, 0, err
}
if *cursor >= l || buff[*cursor] != ':' {
return 0, 0, ErrInvalidTimeFormat
}
*cursor++
minute, err := parseMinute(buff, cursor, l)
if err != nil {
return 0, 0, err
}
return hour, minute, nil
}
func toNSec(sec float64) (int, error) {
_, frac := math.Modf(sec)
fracStr := strconv.FormatFloat(frac, 'f', 9, 64)
fracInt, err := strconv.Atoi(fracStr[2:])
if err != nil {
return 0, err
}
return fracInt, nil
}
// ------------------------------------------------
// https://tools.ietf.org/html/rfc5424#section-6.3
// ------------------------------------------------
func parseStructuredData(buff []byte, cursor *int, l int) (string, error) {
var sdData string
var found bool
if *cursor >= l {
return "-", nil
}
if buff[*cursor] == NILVALUE {
*cursor++
return "-", nil
}
if buff[*cursor] != '[' {
return sdData, ErrNoStructuredData
}
from := *cursor
to := from
for to = from; to < l; to++ {
if found {
break
}
b := buff[to]
if b == ']' {
switch t := to + 1; {
case t == l:
found = true
case t <= l && buff[t] == ' ':
found = true
}
}
}
if found {
*cursor = to
return string(buff[from:to]), nil
}
return sdData, ErrNoStructuredData
}
func parseUpToLen(buff []byte, cursor *int, l int, maxLen int, e error) (string, error) {
var to int
var found bool
var result string
max := *cursor + maxLen
for to = *cursor; (to <= max) && (to < l); to++ {
if buff[to] == ' ' {
found = true
break
}
}
if found {
result = string(buff[*cursor:to])
} else if to > max {
to = max // don't go past max
}
*cursor = to
if found {
return result, nil
}
return "", e
}