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Diffstat (limited to 'fs/fdos/fat.c')
-rw-r--r--fs/fdos/fat.c85
1 files changed, 41 insertions, 44 deletions
diff --git a/fs/fdos/fat.c b/fs/fdos/fat.c
index 42df755..2ef2371 100644
--- a/fs/fdos/fat.c
+++ b/fs/fdos/fat.c
@@ -33,24 +33,24 @@
/*-----------------------------------------------------------------------------
- * fat_decode --
+ * fat_decode --
*-----------------------------------------------------------------------------
*/
unsigned int fat_decode (Fs_t *fs, unsigned int num)
{
unsigned int start = num * 3 / 2;
unsigned char *address = fs -> fat_buf + start;
-
+
if (num < 2 || start + 1 > (fs -> fat_len * SZ_STD_SECTOR))
- return 1;
-
+ return 1;
+
if (num & 1)
- return ((address [1] & 0xff) << 4) | ((address [0] & 0xf0 ) >> 4);
+ return ((address [1] & 0xff) << 4) | ((address [0] & 0xf0 ) >> 4);
else
- return ((address [1] & 0xf) << 8) | (address [0] & 0xff );
+ return ((address [1] & 0xf) << 8) | (address [0] & 0xff );
}
/*-----------------------------------------------------------------------------
- * check_fat --
+ * check_fat --
*-----------------------------------------------------------------------------
*/
static int check_fat (Fs_t *fs)
@@ -59,48 +59,48 @@ static int check_fat (Fs_t *fs)
/* Cluster verification */
for (i = 3 ; i < fs -> num_clus; i++){
- f = fat_decode (fs, i);
- if (f < FAT12_LAST && f > fs -> num_clus){
- /* Wrong cluster number detected */
- return (-1);
- }
+ f = fat_decode (fs, i);
+ if (f < FAT12_LAST && f > fs -> num_clus){
+ /* Wrong cluster number detected */
+ return (-1);
+ }
}
return (0);
}
/*-----------------------------------------------------------------------------
- * read_one_fat --
+ * read_one_fat --
*-----------------------------------------------------------------------------
*/
static int read_one_fat (BootSector_t *boot, Fs_t *fs, int nfat)
{
if (dev_read (fs -> fat_buf,
- (fs -> fat_start + nfat * fs -> fat_len),
- fs -> fat_len) < 0) {
- return (-1);
+ (fs -> fat_start + nfat * fs -> fat_len),
+ fs -> fat_len) < 0) {
+ return (-1);
}
if (fs -> fat_buf [0] || fs -> fat_buf [1] || fs -> fat_buf [2]) {
- if ((fs -> fat_buf [0] != boot -> descr &&
- (fs -> fat_buf [0] != 0xf9 || boot -> descr != MEDIA_STD)) ||
- fs -> fat_buf [0] < MEDIA_STD){
- /* Unknown Media */
- return (-1);
- }
- if (fs -> fat_buf [1] != 0xff || fs -> fat_buf [2] != 0xff){
- /* FAT doesn't start with good values */
- return (-1);
- }
+ if ((fs -> fat_buf [0] != boot -> descr &&
+ (fs -> fat_buf [0] != 0xf9 || boot -> descr != MEDIA_STD)) ||
+ fs -> fat_buf [0] < MEDIA_STD){
+ /* Unknown Media */
+ return (-1);
+ }
+ if (fs -> fat_buf [1] != 0xff || fs -> fat_buf [2] != 0xff){
+ /* FAT doesn't start with good values */
+ return (-1);
+ }
}
if (fs -> num_clus >= FAT12_MAX_NB) {
- /* Too much clusters */
- return (-1);
+ /* Too much clusters */
+ return (-1);
}
return check_fat (fs);
}
/*-----------------------------------------------------------------------------
- * read_fat --
+ * read_fat --
*-----------------------------------------------------------------------------
*/
int read_fat (BootSector_t *boot, Fs_t *fs)
@@ -111,35 +111,32 @@ int read_fat (BootSector_t *boot, Fs_t *fs)
/* Allocate Fat Buffer */
buflen = fs -> fat_len * SZ_STD_SECTOR;
if (fs -> fat_buf) {
- free (fs -> fat_buf);
+ free (fs -> fat_buf);
}
if ((fs -> fat_buf = malloc (buflen)) == NULL) {
- return (-1);
+ return (-1);
}
/* Try to read each Fat */
for (i = 0; i< fs -> nb_fat; i++){
- if (read_one_fat (boot, fs, i) == 0) {
- /* Fat is OK */
- fs -> num_fat = i;
- break;
- }
+ if (read_one_fat (boot, fs, i) == 0) {
+ /* Fat is OK */
+ fs -> num_fat = i;
+ break;
+ }
}
if (i == fs -> nb_fat){
- return (-1);
+ return (-1);
}
-
+
if (fs -> fat_len > (((fs -> num_clus + 2) *
- (FAT_BITS / 4) -1 ) / 2 /
- SZ_STD_SECTOR + 1)) {
- return (-1);
+ (FAT_BITS / 4) -1 ) / 2 /
+ SZ_STD_SECTOR + 1)) {
+ return (-1);
}
return (0);
}
-
-
-
#endif