2021-06-25 09:30:10 +02:00

84 lines
2.6 KiB
Go

package tar
import (
"fmt"
"net/url"
"os"
"path/filepath"
"regexp"
"strings"
)
//https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
var reservedNames = [...]string{"CON", "PRN", "AUX", "NUL", "COM1", "COM2", "COM3", "COM4", "COM5", "COM6", "COM7", "COM8", "COM9", "LPT1", "LPT2", "LPT3", "LPT4", "LPT5", "LPT6", "LPT7", "LPT8", "LPT9"}
var reservedCharsRegex *regexp.Regexp
const reservedCharsStr = `[<>:"\\|?*]` //NOTE: `/` is not included as it is our standard path separator
const reservedNamesRegexFmt = `(?i)^(%s)(?: *%s*)?[^\w ]` // $reservedName, $reservedCharsStr
func init() {
reservedCharsRegex = regexp.MustCompile(reservedCharsStr)
}
func isNullDevice(path string) bool {
if len(path) != 3 {
return false
}
if path[0]|0x20 != 'n' {
return false
}
if path[1]|0x20 != 'u' {
return false
}
if path[2]|0x20 != 'l' {
return false
}
return true
}
func sanitizePath(path string) (string, error) {
pathElements := strings.Split(path, "/")
//first pass: strip illegal tail & prefix reserved names `CON .` -> `_CON`
for pi := range pathElements {
pathElements[pi] = strings.TrimRight(pathElements[pi], ". ") //MSDN: Do not end a file or directory name with a space or a period
for _, rn := range reservedNames {
re, _ := regexp.Compile(fmt.Sprintf(reservedNamesRegexFmt, rn, reservedCharsStr)) //no err, regex is a constant with guaranteed constant arguments
if matched := re.MatchString(pathElements[pi]); matched {
pathElements[pi] = "_" + pathElements[pi]
break
}
}
}
//second pass: scan and encode reserved characters ? -> %3F
res := strings.Join(pathElements, `/`) //intentionally avoiding [file]path.Clean() being called with Join(); we do our own filtering first
illegalIndices := reservedCharsRegex.FindAllStringIndex(res, -1)
if illegalIndices != nil {
var lastIndex int
var builder strings.Builder
allocAssist := (len(res) - len(illegalIndices)) + (len(illegalIndices) * 3) //3 = encoded length
builder.Grow(allocAssist)
for _, si := range illegalIndices {
builder.WriteString(res[lastIndex:si[0]]) //append up to problem char
builder.WriteString(url.QueryEscape(res[si[0]:si[1]])) //escape and append problem char
lastIndex = si[1]
}
builder.WriteString(res[lastIndex:]) //append remainder
res = builder.String()
}
return filepath.FromSlash(res), nil
}
func platformLink(inLink Link) error {
if strings.HasPrefix(inLink.Target, string(os.PathSeparator)) || strings.HasPrefix(inLink.Target, "/") {
return fmt.Errorf("Link target %q is relative to drive root (forbidden)", inLink.Target)
}
return nil
}