int encode_devnode_name(const char *str, char *str_enc, size_t len) {
size_t i, j;
if (!str || !str_enc)
return -EINVAL;
for (i = 0, j = 0; str[i] != '\0'; i++) {
int seqlen;
seqlen = utf8_encoded_valid_unichar(&str[i]);
if (seqlen > 1) {
if (len-j < (size_t)seqlen)
return -EINVAL;
memcpy(&str_enc[j], &str[i], seqlen);
j += seqlen;
i += (seqlen-1);
} else if (str[i] == '\\' || !whitelisted_char_for_devnode(str[i], NULL)) {
if (len-j < 4)
return -EINVAL;
sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
j += 4;
} else {
if (len-j < 1)
return -EINVAL;
str_enc[j] = str[i];
j++;
}
}
if (len-j < 1)
return -EINVAL;
str_enc[j] = '\0';
return 0;
}
/* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
size_t util_replace_chars(char *str, const char *white) {
size_t i = 0, replaced = 0;
assert(str);
while (str[i] != '\0') {
int len;
if (whitelisted_char_for_devnode(str[i], white)) {
i++;
continue;
}
/* accept hex encoding */
if (str[i] == '\\' && str[i+1] == 'x') {
i += 2;
continue;
}
/* accept valid utf8 */
len = utf8_encoded_valid_unichar(str + i, (size_t) -1);
if (len > 1) {
i += len;
continue;
}
/* if space is allowed, replace whitespace with ordinary space */
if (isspace(str[i]) && white && strchr(white, ' ')) {
str[i] = ' ';
i++;
replaced++;
continue;
}
/* everything else is replaced with '_' */
str[i] = '_';
i++;
replaced++;
}
return replaced;
}
