// Read a buffer (dir) into the pointer to the DirentBuf, `db`
// Returns remaining buffer size and number of entries created
// It's a modified version of syscall.ParseDirent in Go's standard library
func ParseDir(buf []byte, max int64, db *[]syscall.Dirent) (int, int) {
orig := len(buf)
i := int64(0)
for max != 0 && len(buf) > 0 {
dirent := *(*syscall.Dirent)(unsafe.Pointer(&buf[0]))
buf = buf[dirent.Reclen:]
if dirent.Ino == 0 {
continue
}
b := (*[257]byte)(unsafe.Pointer(&dirent.Name[0]))
bn := string(b[0:general.Clen(b[:])])
if bn == "." || bn == ".." {
continue
}
if len(*db) <= int(i) {
*db = append(*db, dirent)
} else {
(*db)[i] = dirent
}
max--
i++
}
return orig - len(buf), int(i)
}
// recursively walk through the named directory `dir` until the correct device
// is found.
// Directories in []searchDevs are automatically skipped
func checkDirs(dir string) (string, error) {
var (
rs string
nameBuf = make([]byte, 256)
dirBuf = make([]syscall.Dirent, 256)
)
fi, err := os.Open(dir)
if err != nil {
return "", err
}
defer fi.Close()
err = dirent.ReadDir(int(fi.Fd()), -1, &dirBuf)
if err != nil && err != io.EOF {
return "", err
}
for _, v := range dirBuf {
// quickly skip most entries
if v.Ino != Stat.Ino {
continue
}
_ = copy(nameBuf, general.Int8ToByte(v.Name[:]))
name := path.Join(dir, string(nameBuf[:general.Clen(nameBuf)]))
// Directories to skip
if name == "/dev/stderr" ||
name == "/dev/stdin" ||
name == "/dev/stdout" ||
(len(name) >= 8 &&
name[0:8] == "/dev/fd/") {
continue
}
// We have to stat the file to determine its Rdev
fstat := new(syscall.Stat_t)
err = syscall.Stat(name, fstat)
if err != nil {
continue
}
// file mode sans permission bits
fmode := os.FileMode(fstat.Mode)
if fmode.IsDir() {
rs, err = checkDirs(name)
if err != nil {
continue
}
return rs, nil
}
if fmode&os.ModeCharDevice == 0 &&
fstat.Ino == Stat.Ino &&
fstat.Rdev == Stat.Rdev {
return name, nil
}
}
return "", ErrNotFound
}
// Return stringified version of a username.
// Trims after first null byte
func (u *Utmp) ExtractTrimmedName() string {
return string(u.User[:general.Clen(u.User[:])])
}