use libblkid to get filesystem type
we can now use libblkid to detect exfat
diff --git a/libblkid/encode.c b/libblkid/encode.c
new file mode 100644
index 0000000..ff57be4
--- /dev/null
+++ b/libblkid/encode.c
@@ -0,0 +1,340 @@
+
+/*
+ * encode.c - string conversion routines (mostly for compatibility with
+ * udev/volume_id)
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <ctype.h>
+
+#include "blkidP.h"
+
+#define UDEV_ALLOWED_CHARS_INPUT "/ $%?,"
+
+/**
+ * SECTION: encode
+ * @title: Encoding utils
+ * @short_description: encode strings to safe udev-compatible formats
+ *
+ */
+
+/* count of characters used to encode one unicode char */
+static int utf8_encoded_expected_len(const char *str)
+{
+ unsigned char c = (unsigned char)str[0];
+
+ if (c < 0x80)
+ return 1;
+ if ((c & 0xe0) == 0xc0)
+ return 2;
+ if ((c & 0xf0) == 0xe0)
+ return 3;
+ if ((c & 0xf8) == 0xf0)
+ return 4;
+ if ((c & 0xfc) == 0xf8)
+ return 5;
+ if ((c & 0xfe) == 0xfc)
+ return 6;
+ return 0;
+}
+
+/* decode one unicode char */
+static int utf8_encoded_to_unichar(const char *str)
+{
+ int unichar;
+ int len;
+ int i;
+
+ len = utf8_encoded_expected_len(str);
+ switch (len) {
+ case 1:
+ return (int)str[0];
+ case 2:
+ unichar = str[0] & 0x1f;
+ break;
+ case 3:
+ unichar = (int)str[0] & 0x0f;
+ break;
+ case 4:
+ unichar = (int)str[0] & 0x07;
+ break;
+ case 5:
+ unichar = (int)str[0] & 0x03;
+ break;
+ case 6:
+ unichar = (int)str[0] & 0x01;
+ break;
+ default:
+ return -1;
+ }
+
+ for (i = 1; i < len; i++) {
+ if (((int)str[i] & 0xc0) != 0x80)
+ return -1;
+ unichar <<= 6;
+ unichar |= (int)str[i] & 0x3f;
+ }
+
+ return unichar;
+}
+
+/* expected size used to encode one unicode char */
+static int utf8_unichar_to_encoded_len(int unichar)
+{
+ if (unichar < 0x80)
+ return 1;
+ if (unichar < 0x800)
+ return 2;
+ if (unichar < 0x10000)
+ return 3;
+ if (unichar < 0x200000)
+ return 4;
+ if (unichar < 0x4000000)
+ return 5;
+ return 6;
+}
+
+/* check if unicode char has a valid numeric range */
+static int utf8_unichar_valid_range(int unichar)
+{
+ if (unichar > 0x10ffff)
+ return 0;
+ if ((unichar & 0xfffff800) == 0xd800)
+ return 0;
+ if ((unichar > 0xfdcf) && (unichar < 0xfdf0))
+ return 0;
+ if ((unichar & 0xffff) == 0xffff)
+ return 0;
+ return 1;
+}
+
+/* validate one encoded unicode char and return its length */
+static int utf8_encoded_valid_unichar(const char *str)
+{
+ int len;
+ int unichar;
+ int i;
+
+ len = utf8_encoded_expected_len(str);
+ if (len == 0)
+ return -1;
+
+ /* ascii is valid */
+ if (len == 1)
+ return 1;
+
+ /* check if expected encoded chars are available */
+ for (i = 0; i < len; i++)
+ if ((str[i] & 0x80) != 0x80)
+ return -1;
+
+ unichar = utf8_encoded_to_unichar(str);
+
+ /* check if encoded length matches encoded value */
+ if (utf8_unichar_to_encoded_len(unichar) != len)
+ return -1;
+
+ /* check if value has valid range */
+ if (!utf8_unichar_valid_range(unichar))
+ return -1;
+
+ return len;
+}
+
+static int replace_whitespace(const char *str, char *to, size_t len)
+{
+ size_t i, j;
+
+ /* strip trailing whitespace */
+ len = strnlen(str, len);
+ while (len && isspace(str[len-1]))
+ len--;
+
+ /* strip leading whitespace */
+ i = 0;
+ while (isspace(str[i]) && (i < len))
+ i++;
+
+ j = 0;
+ while (i < len) {
+ /* substitute multiple whitespace with a single '_' */
+ if (isspace(str[i])) {
+ while (isspace(str[i]))
+ i++;
+ to[j++] = '_';
+ }
+ to[j++] = str[i++];
+ }
+ to[j] = '\0';
+ return 0;
+}
+
+static int is_whitelisted(char c, const char *white)
+{
+ if ((c >= '0' && c <= '9') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= 'a' && c <= 'z') ||
+ strchr("#+-.:=@_", c) != NULL ||
+ (white != NULL && strchr(white, c) != NULL))
+ return 1;
+ return 0;
+}
+
+/* allow chars in whitelist, plain ascii, hex-escaping and valid utf8 */
+static int replace_chars(char *str, const char *white)
+{
+ size_t i = 0;
+ int replaced = 0;
+
+ while (str[i] != '\0') {
+ int len;
+
+ if (is_whitelisted(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]);
+ if (len > 1) {
+ i += len;
+ continue;
+ }
+
+ /* if space is allowed, replace whitespace with ordinary space */
+ if (isspace(str[i]) && white != NULL && strchr(white, ' ') != NULL) {
+ str[i] = ' ';
+ i++;
+ replaced++;
+ continue;
+ }
+
+ /* everything else is replaced with '_' */
+ str[i] = '_';
+ i++;
+ replaced++;
+ }
+ return replaced;
+}
+
+size_t blkid_encode_to_utf8(int enc, unsigned char *dest, size_t len,
+ const unsigned char *src, size_t count)
+{
+ size_t i, j;
+ uint16_t c;
+
+ for (j = i = 0; i + 2 <= count; i += 2) {
+ if (enc == BLKID_ENC_UTF16LE)
+ c = (src[i+1] << 8) | src[i];
+ else /* BLKID_ENC_UTF16BE */
+ c = (src[i] << 8) | src[i+1];
+ if (c == 0) {
+ dest[j] = '\0';
+ break;
+ } else if (c < 0x80) {
+ if (j+1 >= len)
+ break;
+ dest[j++] = (uint8_t) c;
+ } else if (c < 0x800) {
+ if (j+2 >= len)
+ break;
+ dest[j++] = (uint8_t) (0xc0 | (c >> 6));
+ dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
+ } else {
+ if (j+3 >= len)
+ break;
+ dest[j++] = (uint8_t) (0xe0 | (c >> 12));
+ dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
+ dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
+ }
+ }
+ dest[j] = '\0';
+ return j;
+}
+
+/**
+ * blkid_encode_string:
+ * @str: input string to be encoded
+ * @str_enc: output string to store the encoded input string
+ * @len: maximum size of the output string, which may be
+ * four times as long as the input string
+ *
+ * Encode all potentially unsafe characters of a string to the
+ * corresponding hex value prefixed by '\x'.
+ *
+ * Returns: 0 if the entire string was copied, non-zero otherwise.
+ **/
+int blkid_encode_string(const char *str, char *str_enc, size_t len)
+{
+ size_t i, j;
+
+ if (!str || !str_enc || !len)
+ return -1;
+
+ 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)
+ goto err;
+ memcpy(&str_enc[j], &str[i], seqlen);
+ j += seqlen;
+ i += (seqlen-1);
+ } else if (str[i] == '\\' || !is_whitelisted(str[i], NULL)) {
+ if (len-j < 4)
+ goto err;
+ sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
+ j += 4;
+ } else {
+ if (len-j < 1)
+ goto err;
+ str_enc[j] = str[i];
+ j++;
+ }
+ if (j+3 >= len)
+ goto err;
+ }
+ if (len-j < 1)
+ goto err;
+ str_enc[j] = '\0';
+ return 0;
+err:
+ return -1;
+}
+
+/**
+ * blkid_safe_string:
+ * @str: input string
+ * @str_safe: output string
+ * @len: size of output string
+ *
+ * Allows plain ascii, hex-escaping and valid utf8. Replaces all whitespaces
+ * with '_'.
+ *
+ * Returns: 0 on success or -1 in case of error.
+ */
+int blkid_safe_string(const char *str, char *str_safe, size_t len)
+{
+ if (!str || !str_safe || !len)
+ return -1;
+ replace_whitespace(str, str_safe, len);
+ replace_chars(str_safe, UDEV_ALLOWED_CHARS_INPUT);
+ return 0;
+}