use libblkid to get filesystem type
we can now use libblkid to detect exfat
diff --git a/libblkid/cache.c b/libblkid/cache.c
new file mode 100644
index 0000000..cc2cf8e
--- /dev/null
+++ b/libblkid/cache.c
@@ -0,0 +1,275 @@
+/*
+ * cache.c - allocation/initialization/free routines for cache
+ *
+ * Copyright (C) 2001 Andreas Dilger
+ * Copyright (C) 2003 Theodore Ts'o
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ * %End-Header%
+ */
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#ifdef HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#include "blkidP.h"
+#include "env.h"
+
+int blkid_debug_mask = 0;
+
+/**
+ * SECTION:cache
+ * @title: Cache
+ * @short_description: basic routines to work with libblkid cache
+ *
+ * Block device information is normally kept in a cache file blkid.tab and is
+ * verified to still be valid before being returned to the user (if the user has
+ * read permission on the raw block device, otherwise not). The cache file also
+ * allows unprivileged users (normally anyone other than root, or those not in the
+ * "disk" group) to locate devices by label/id. The standard location of the
+ * cache file can be overridden by the environment variable BLKID_FILE.
+ *
+ * In situations where one is getting information about a single known device, it
+ * does not impact performance whether the cache is used or not (unless you are
+ * not able to read the block device directly). If you are dealing with multiple
+ * devices, use of the cache is highly recommended (even if empty) as devices will
+ * be scanned at most one time and the on-disk cache will be updated if possible.
+ * There is rarely a reason not to use the cache.
+ *
+ * In some cases (modular kernels), block devices are not even visible until after
+ * they are accessed the first time, so it is critical that there is some way to
+ * locate these devices without enumerating only visible devices, so the use of
+ * the cache file is required in this situation.
+ */
+
+#if 0 /* ifdef CONFIG_BLKID_DEBUG */
+static blkid_debug_dump_cache(int mask, blkid_cache cache)
+{
+ struct list_head *p;
+
+ if (!cache) {
+ printf("cache: NULL\n");
+ return;
+ }
+
+ printf("cache: time = %lu\n", cache->bic_time);
+ printf("cache: flags = 0x%08X\n", cache->bic_flags);
+
+ list_for_each(p, &cache->bic_devs) {
+ blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
+ blkid_debug_dump_dev(dev);
+ }
+}
+#endif
+
+#ifdef CONFIG_BLKID_DEBUG
+void blkid_init_debug(int mask)
+{
+ if (blkid_debug_mask & DEBUG_INIT)
+ return;
+
+ if (!mask)
+ {
+ char *dstr = getenv("LIBBLKID_DEBUG");
+
+ if (!dstr)
+ dstr = getenv("BLKID_DEBUG"); /* for backward compatibility */
+ if (dstr)
+ blkid_debug_mask = strtoul(dstr, 0, 0);
+ } else
+ blkid_debug_mask = mask;
+
+ if (blkid_debug_mask)
+ printf("libblkid: debug mask set to 0x%04x.\n", blkid_debug_mask);
+
+ blkid_debug_mask |= DEBUG_INIT;
+}
+#endif
+
+static const char *get_default_cache_filename(void)
+{
+ struct stat st;
+
+ if (stat(BLKID_RUNTIME_TOPDIR, &st) == 0 && S_ISDIR(st.st_mode))
+ return BLKID_CACHE_FILE; /* cache in /run */
+
+ return BLKID_CACHE_FILE_OLD; /* cache in /etc */
+}
+
+/* returns allocated path to cache */
+char *blkid_get_cache_filename(struct blkid_config *conf)
+{
+ char *filename;
+
+ filename = safe_getenv("BLKID_FILE");
+ if (filename)
+ filename = strdup(filename);
+ else if (conf)
+ filename = conf->cachefile ? strdup(conf->cachefile) : NULL;
+ else {
+ struct blkid_config *c = blkid_read_config(NULL);
+ if (!c)
+ filename = strdup(get_default_cache_filename());
+ else {
+ filename = c->cachefile; /* already allocated */
+ c->cachefile = NULL;
+ blkid_free_config(c);
+ }
+ }
+ return filename;
+}
+
+/**
+ * blkid_get_cache:
+ * @cache: pointer to return cache handler
+ * @filename: path to the cache file or NULL for the default path
+ *
+ * Allocates and initialize librray cache handler.
+ *
+ * Returns: 0 on success or number less than zero in case of error.
+ */
+int blkid_get_cache(blkid_cache *ret_cache, const char *filename)
+{
+ blkid_cache cache;
+
+ if (!ret_cache)
+ return -BLKID_ERR_PARAM;
+
+ blkid_init_debug(0);
+
+ DBG(DEBUG_CACHE, printf("creating blkid cache (using %s)\n",
+ filename ? filename : "default cache"));
+
+ if (!(cache = (blkid_cache) calloc(1, sizeof(struct blkid_struct_cache))))
+ return -BLKID_ERR_MEM;
+
+ INIT_LIST_HEAD(&cache->bic_devs);
+ INIT_LIST_HEAD(&cache->bic_tags);
+
+ if (filename && !*filename)
+ filename = NULL;
+ if (filename)
+ cache->bic_filename = strdup(filename);
+ else
+ cache->bic_filename = blkid_get_cache_filename(NULL);
+
+ blkid_read_cache(cache);
+ *ret_cache = cache;
+ return 0;
+}
+
+/**
+ * blkid_put_cache:
+ * @cache: cache handler
+ *
+ * Saves changes to cache file.
+ */
+void blkid_put_cache(blkid_cache cache)
+{
+ if (!cache)
+ return;
+
+ (void) blkid_flush_cache(cache);
+
+ DBG(DEBUG_CACHE, printf("freeing cache struct\n"));
+
+ /* DBG(DEBUG_CACHE, blkid_debug_dump_cache(cache)); */
+
+ while (!list_empty(&cache->bic_devs)) {
+ blkid_dev dev = list_entry(cache->bic_devs.next,
+ struct blkid_struct_dev,
+ bid_devs);
+ blkid_free_dev(dev);
+ }
+
+ while (!list_empty(&cache->bic_tags)) {
+ blkid_tag tag = list_entry(cache->bic_tags.next,
+ struct blkid_struct_tag,
+ bit_tags);
+
+ while (!list_empty(&tag->bit_names)) {
+ blkid_tag bad = list_entry(tag->bit_names.next,
+ struct blkid_struct_tag,
+ bit_names);
+
+ DBG(DEBUG_CACHE, printf("warning: unfreed tag %s=%s\n",
+ bad->bit_name, bad->bit_val));
+ blkid_free_tag(bad);
+ }
+ blkid_free_tag(tag);
+ }
+
+ blkid_free_probe(cache->probe);
+
+ free(cache->bic_filename);
+ free(cache);
+}
+
+/**
+ * blkid_gc_cache:
+ * @cache: cache handler
+ *
+ * Removes garbage (non-existing devices) from the cache.
+ */
+void blkid_gc_cache(blkid_cache cache)
+{
+ struct list_head *p, *pnext;
+ struct stat st;
+
+ if (!cache)
+ return;
+
+ list_for_each_safe(p, pnext, &cache->bic_devs) {
+ blkid_dev dev = list_entry(p, struct blkid_struct_dev, bid_devs);
+ if (stat(dev->bid_name, &st) < 0) {
+ DBG(DEBUG_CACHE,
+ printf("freeing %s\n", dev->bid_name));
+ blkid_free_dev(dev);
+ cache->bic_flags |= BLKID_BIC_FL_CHANGED;
+ } else {
+ DBG(DEBUG_CACHE,
+ printf("Device %s exists\n", dev->bid_name));
+ }
+ }
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char** argv)
+{
+ blkid_cache cache = NULL;
+ int ret;
+
+ blkid_init_debug(DEBUG_ALL);
+
+ if ((argc > 2)) {
+ fprintf(stderr, "Usage: %s [filename] \n", argv[0]);
+ exit(1);
+ }
+
+ if ((ret = blkid_get_cache(&cache, argv[1])) < 0) {
+ fprintf(stderr, "error %d parsing cache file %s\n", ret,
+ argv[1] ? argv[1] : blkid_get_cache_filename(NULL));
+ exit(1);
+ }
+ if ((ret = blkid_get_cache(&cache, "/dev/null")) != 0) {
+ fprintf(stderr, "%s: error creating cache (%d)\n",
+ argv[0], ret);
+ exit(1);
+ }
+ if ((ret = blkid_probe_all(cache)) < 0)
+ fprintf(stderr, "error probing devices\n");
+
+ blkid_put_cache(cache);
+
+ return ret;
+}
+#endif