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// Copyright 2023 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
package linux
import (
"bufio"
"fmt"
"io"
"net/mail"
"path/filepath"
"regexp"
"strings"
"unicode"
"github.com/google/syzkaller/pkg/subsystem"
)
// maintainersRecord represents a single raw record in the MAINTAINERS file.
type maintainersRecord struct {
name string
includePatterns []string
excludePatterns []string
regexps []string
lists []string
maintainers []string
trees []string
}
func parseLinuxMaintainers(content io.Reader) ([]*maintainersRecord, error) {
scanner := bufio.NewScanner(content)
// First skip the headers.
var skippedLines int
for scanner.Scan() {
skippedLines++
line := scanner.Text()
if line == "Maintainers List" {
// Also skip ------.
scanner.Scan()
break
}
}
ml := &maintainersLexer{scanner: scanner, currentLine: skippedLines + 1}
ret := []*maintainersRecord{}
loop:
for {
item := ml.next()
switch v := item.(type) {
case recordTitle:
// The new subsystem begins.
ret = append(ret, &maintainersRecord{name: string(v)})
case recordProperty:
if len(ret) == 0 {
return nil, fmt.Errorf("line %d: property without subsystem", ml.currentLine)
}
err := applyProperty(ret[len(ret)-1], &v)
if err != nil {
return nil, fmt.Errorf("line %d: failed to apply the property %#v: %w",
ml.currentLine, v, err)
}
case endOfFile:
break loop
}
}
if err := scanner.Err(); err != nil {
return nil, err
}
return ret, nil
}
type maintainersLexer struct {
scanner *bufio.Scanner
currentLine int
inComment bool
}
type recordTitle string
type recordProperty struct {
key string
value string
}
type endOfFile struct{}
var propertyRe = regexp.MustCompile(`^([[:alpha:]]):\s+(.*).*$`)
func (ml *maintainersLexer) next() any {
for ml.scanner.Scan() {
ml.currentLine++
rawLine := ml.scanner.Text()
line := strings.TrimSpace(rawLine)
if strings.HasPrefix(line, ".") {
ml.inComment = true
continue
}
// A comment continues to the next line(s) if they begin with a space character.
if ml.inComment && (line == "" || !unicode.IsSpace(rune(rawLine[0]))) {
ml.inComment = false
}
if ml.inComment || line == "" {
continue
}
// Now let's consider the possible line types.
if matches := propertyRe.FindStringSubmatch(line); matches != nil {
return recordProperty{key: matches[1], value: matches[2]}
}
return recordTitle(line)
}
return endOfFile{}
}
func applyProperty(record *maintainersRecord, property *recordProperty) error {
switch property.key {
case "F":
record.includePatterns = append(record.includePatterns, property.value)
case "X":
record.excludePatterns = append(record.excludePatterns, property.value)
case "N":
if _, err := regexp.Compile(property.value); err != nil {
return fmt.Errorf("invalid regexp: %s", property.value)
}
record.regexps = append(record.regexps, property.value)
case "M":
value, err := parseEmail(property.value)
if err != nil {
return err
}
record.maintainers = append(record.maintainers, value)
case "L":
value, err := parseEmail(property.value)
if err != nil {
return err
}
record.lists = append(record.lists, value)
case "T":
record.trees = append(record.trees, property.value)
}
return nil
}
func parseEmail(value string) (string, error) {
// Sometimes there happen extra symbols at the end of the line,
// let's make this parser more error tolerant.
if pos := strings.LastIndexAny(value, ">)"); pos >= 0 {
value = value[:pos+1]
}
// Let's also make the parser more robust by skipping everything before the first <,
// if it exists.
if pos := strings.LastIndexAny(value, "<"); pos >= 0 {
value = value[pos:]
}
addr, err := mail.ParseAddress(value)
if err != nil {
return "", err
}
return addr.Address, nil
}
func (r maintainersRecord) ToPathRule() subsystem.PathRule {
inclRe := strings.Builder{}
for i, wildcard := range r.includePatterns {
if i > 0 {
inclRe.WriteByte('|')
}
wildcardToRegexp(wildcard, &inclRe)
}
for _, rg := range r.regexps {
if inclRe.Len() > 0 {
inclRe.WriteByte('|')
}
inclRe.WriteString(rg)
}
exclRe := strings.Builder{}
for i, wildcard := range r.excludePatterns {
if i > 0 {
exclRe.WriteByte('|')
}
wildcardToRegexp(wildcard, &exclRe)
}
return subsystem.PathRule{
IncludeRegexp: inclRe.String(),
ExcludeRegexp: exclRe.String(),
}
}
func removeMatchingPatterns(records []*maintainersRecord, rule *regexp.Regexp) {
filter := func(list []string) []string {
ret := []string{}
for _, item := range list {
if !rule.MatchString(item) {
ret = append(ret, item)
}
}
return ret
}
for _, record := range records {
record.includePatterns = filter(record.includePatterns)
record.excludePatterns = filter(record.excludePatterns)
}
}
var (
escapedSeparator = regexp.QuoteMeta(fmt.Sprintf("%c", filepath.Separator))
wildcardReplace = map[byte]string{
'*': `[^` + escapedSeparator + `]*`,
'?': `.`,
'/': escapedSeparator,
}
)
func wildcardToRegexp(wildcard string, store *strings.Builder) {
store.WriteByte('^')
// We diverge a bit from the standard MAINTAINERS rule semantics.
// path/* corresponds to the files belonging to the `path` folder,
// but, since we also infer the parent-child relationship, it's
// easier to make it cover the whole subtree.
if len(wildcard) >= 2 && wildcard[len(wildcard)-2:] == "/*" {
wildcard = wildcard[:len(wildcard)-1]
}
tokenStart := 0
for i, c := range wildcard {
replace, exists := wildcardReplace[byte(c)]
if !exists {
continue
}
store.WriteString(regexp.QuoteMeta(wildcard[tokenStart:i]))
store.WriteString(replace)
tokenStart = i + 1
}
if tokenStart < len(wildcard) {
store.WriteString(regexp.QuoteMeta(wildcard[tokenStart:]))
}
if wildcard == "" || wildcard[len(wildcard)-1] != '/' {
store.WriteByte('$')
}
}
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