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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package filepath
import (
"errors"
"os"
"runtime"
"sort"
"strings"
"unicode/utf8"
)
// ErrBadPattern indicates a pattern was malformed.
var ErrBadPattern = errors.New("syntax error in pattern")
// Match reports whether name matches the shell file name pattern.
// The pattern syntax is:
//
// pattern:
// { term }
// term:
// '*' matches any sequence of non-Separator characters
// '?' matches any single non-Separator character
// '[' [ '^' ] { character-range } ']'
// character class (must be non-empty)
// c matches character c (c != '*', '?', '\\', '[')
// '\\' c matches character c
//
// character-range:
// c matches character c (c != '\\', '-', ']')
// '\\' c matches character c
// lo '-' hi matches character c for lo <= c <= hi
//
// Match requires pattern to match all of name, not just a substring.
// The only possible returned error is ErrBadPattern, when pattern
// is malformed.
//
// On Windows, escaping is disabled. Instead, '\\' is treated as
// path separator.
func Match(pattern, name string) (matched bool, err error) {
Pattern:
for len(pattern) > 0 {
var star bool
var chunk string
star, chunk, pattern = scanChunk(pattern)
if star && chunk == "" {
// Trailing * matches rest of string unless it has a /.
return !strings.Contains(name, string(Separator)), nil
}
// Look for match at current position.
t, ok, err := matchChunk(chunk, name)
// if we're the last chunk, make sure we've exhausted the name
// otherwise we'll give a false result even if we could still match
// using the star
if ok && (len(t) == 0 || len(pattern) > 0) {
name = t
continue
}
if err != nil {
return false, err
}
if star {
// Look for match skipping i+1 bytes.
// Cannot skip /.
for i := 0; i < len(name) && name[i] != Separator; i++ {
t, ok, err := matchChunk(chunk, name[i+1:])
if ok {
// if we're the last chunk, make sure we exhausted the name
if len(pattern) == 0 && len(t) > 0 {
continue
}
name = t
continue Pattern
}
if err != nil {
return false, err
}
}
}
return false, nil
}
return len(name) == 0, nil
}
// scanChunk gets the next segment of pattern, which is a non-star string
// possibly preceded by a star.
func scanChunk(pattern string) (star bool, chunk, rest string) {
for len(pattern) > 0 && pattern[0] == '*' {
pattern = pattern[1:]
star = true
}
inrange := false
var i int
Scan:
for i = 0; i < len(pattern); i++ {
switch pattern[i] {
case '\\':
if runtime.GOOS != "windows" {
// error check handled in matchChunk: bad pattern.
if i+1 < len(pattern) {
i++
}
}
case '[':
inrange = true
case ']':
inrange = false
case '*':
if !inrange {
break Scan
}
}
}
return star, pattern[0:i], pattern[i:]
}
// matchChunk checks whether chunk matches the beginning of s.
// If so, it returns the remainder of s (after the match).
// Chunk is all single-character operators: literals, char classes, and ?.
func matchChunk(chunk, s string) (rest string, ok bool, err error) {
// failed records whether the match has failed.
// After the match fails, the loop continues on processing chunk,
// checking that the pattern is well-formed but no longer reading s.
failed := false
for len(chunk) > 0 {
if !failed && len(s) == 0 {
failed = true
}
switch chunk[0] {
case '[':
// character class
var r rune
if !failed {
var n int
r, n = utf8.DecodeRuneInString(s)
s = s[n:]
}
chunk = chunk[1:]
// possibly negated
negated := false
if len(chunk) > 0 && chunk[0] == '^' {
negated = true
chunk = chunk[1:]
}
// parse all ranges
match := false
nrange := 0
for {
if len(chunk) > 0 && chunk[0] == ']' && nrange > 0 {
chunk = chunk[1:]
break
}
var lo, hi rune
if lo, chunk, err = getEsc(chunk); err != nil {
return "", false, err
}
hi = lo
if chunk[0] == '-' {
if hi, chunk, err = getEsc(chunk[1:]); err != nil {
return "", false, err
}
}
if lo <= r && r <= hi {
match = true
}
nrange++
}
if match == negated {
failed = true
}
case '?':
if !failed {
if s[0] == Separator {
failed = true
}
_, n := utf8.DecodeRuneInString(s)
s = s[n:]
}
chunk = chunk[1:]
case '\\':
if runtime.GOOS != "windows" {
chunk = chunk[1:]
if len(chunk) == 0 {
return "", false, ErrBadPattern
}
}
fallthrough
default:
if !failed {
if chunk[0] != s[0] {
failed = true
}
s = s[1:]
}
chunk = chunk[1:]
}
}
if failed {
return "", false, nil
}
return s, true, nil
}
// getEsc gets a possibly-escaped character from chunk, for a character class.
func getEsc(chunk string) (r rune, nchunk string, err error) {
if len(chunk) == 0 || chunk[0] == '-' || chunk[0] == ']' {
err = ErrBadPattern
return
}
if chunk[0] == '\\' && runtime.GOOS != "windows" {
chunk = chunk[1:]
if len(chunk) == 0 {
err = ErrBadPattern
return
}
}
r, n := utf8.DecodeRuneInString(chunk)
if r == utf8.RuneError && n == 1 {
err = ErrBadPattern
}
nchunk = chunk[n:]
if len(nchunk) == 0 {
err = ErrBadPattern
}
return
}
// Glob returns the names of all files matching pattern or nil
// if there is no matching file. The syntax of patterns is the same
// as in Match. The pattern may describe hierarchical names such as
// /usr/*/bin/ed (assuming the Separator is '/').
//
// Glob ignores file system errors such as I/O errors reading directories.
// The only possible returned error is ErrBadPattern, when pattern
// is malformed.
func Glob(pattern string) (matches []string, err error) {
return globWithLimit(pattern, 0)
}
func globWithLimit(pattern string, depth int) (matches []string, err error) {
// This limit is used prevent stack exhaustion issues. See CVE-2022-30632.
const pathSeparatorsLimit = 10000
if depth == pathSeparatorsLimit {
return nil, ErrBadPattern
}
// Check pattern is well-formed.
if _, err := Match(pattern, ""); err != nil {
return nil, err
}
if !hasMeta(pattern) {
if _, err = os.Lstat(pattern); err != nil {
return nil, nil
}
return []string{pattern}, nil
}
dir, file := Split(pattern)
volumeLen := 0
if runtime.GOOS == "windows" {
volumeLen, dir = cleanGlobPathWindows(dir)
} else {
dir = cleanGlobPath(dir)
}
if !hasMeta(dir[volumeLen:]) {
return glob(dir, file, nil)
}
// Prevent infinite recursion. See issue 15879.
if dir == pattern {
return nil, ErrBadPattern
}
var m []string
m, err = globWithLimit(dir, depth+1)
if err != nil {
return
}
for _, d := range m {
matches, err = glob(d, file, matches)
if err != nil {
return
}
}
return
}
// cleanGlobPath prepares path for glob matching.
func cleanGlobPath(path string) string {
switch path {
case "":
return "."
case string(Separator):
// do nothing to the path
return path
default:
return path[0 : len(path)-1] // chop off trailing separator
}
}
// cleanGlobPathWindows is windows version of cleanGlobPath.
func cleanGlobPathWindows(path string) (prefixLen int, cleaned string) {
vollen := volumeNameLen(path)
switch {
case path == "":
return 0, "."
case vollen+1 == len(path) && os.IsPathSeparator(path[len(path)-1]): // /, \, C:\ and C:/
// do nothing to the path
return vollen + 1, path
case vollen == len(path) && len(path) == 2: // C:
return vollen, path + "." // convert C: into C:.
default:
if vollen >= len(path) {
vollen = len(path) - 1
}
return vollen, path[0 : len(path)-1] // chop off trailing separator
}
}
// glob searches for files matching pattern in the directory dir
// and appends them to matches. If the directory cannot be
// opened, it returns the existing matches. New matches are
// added in lexicographical order.
func glob(dir, pattern string, matches []string) (m []string, e error) {
m = matches
fi, err := os.Stat(dir)
if err != nil {
return // ignore I/O error
}
if !fi.IsDir() {
return // ignore I/O error
}
d, err := os.Open(dir)
if err != nil {
return // ignore I/O error
}
defer d.Close()
names, _ := d.Readdirnames(-1)
sort.Strings(names)
for _, n := range names {
matched, err := Match(pattern, n)
if err != nil {
return m, err
}
if matched {
m = append(m, Join(dir, n))
}
}
return
}
// hasMeta reports whether path contains any of the magic characters
// recognized by Match.
func hasMeta(path string) bool {
magicChars := `*?[`
if runtime.GOOS != "windows" {
magicChars = `*?[\`
}
return strings.ContainsAny(path, magicChars)
}