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fs: fat: Fix mkcksum() function parameters 

The mkcksum() function now takes one parameter, the pointer to
11-byte wide character array, which it then operates on.

Currently, the function is wrongly passed (dir_entry)->name, which
is only 8-byte wide character array. Though by further inspecting
the dir_entry structure, it can be noticed that the name[8] entry
is immediatelly followed by ext[3] entry. Thus, name[8] and ext[3]
in the dir_entry structure actually work as this 11-byte wide array
since they're placed right next to each other by current compiler
behavior.

Depending on this is obviously wrong, thus fix this by correctly
passing both (dir_entry)->name and (dir_entry)->ext to the mkcksum()
function and adjust the function appropriately.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@ti.com>
This commit is contained in:
Marek Vasut 2012-10-09 07:20:22 +00:00 committed by Tom Rini
parent e2e9b37898
commit ff04f6d122
2 changed files with 13 additions and 9 deletions
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20
fs/fat/fat.c
View File

@ -567,15 +567,16 @@ get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
}
/* Calculate short name checksum */
static __u8 mkcksum(const char *str)
static __u8 mkcksum(const char name[8], const char ext[3])
{
int i;
__u8 ret = 0;
for (i = 0; i < 11; i++) {
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i];
}
for (i = 0; i < sizeof(name); i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
for (i = 0; i < sizeof(ext); i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
return ret;
}
@ -678,7 +679,8 @@ static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
return NULL;
}
#ifdef CONFIG_SUPPORT_VFAT
if (dols && mkcksum(dentptr->name) == prevcksum) {
__u8 csum = mkcksum(dentptr->name, dentptr->ext);
if (dols && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
@ -946,13 +948,16 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
for (i = 0; i < DIRENTSPERBLOCK; i++) {
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
__u8 csum;
l_name[0] = '\0';
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if ((dentptr->attr & ATTR_VOLUME)) {
csum = mkcksum(dentptr->name, dentptr->ext);
if (dentptr->attr & ATTR_VOLUME) {
#ifdef CONFIG_SUPPORT_VFAT
if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
@ -1015,8 +1020,7 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
goto exit;
}
#ifdef CONFIG_SUPPORT_VFAT
else if (dols == LS_ROOT &&
mkcksum(dentptr->name) == prevcksum) {
else if (dols == LS_ROOT && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;

2
fs/fat/fat_write.c
View File

@ -335,7 +335,7 @@ fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
/* Get short file name and checksum value */
strncpy(s_name, (*dentptr)->name, 16);
checksum = mkcksum(s_name);
checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
do {
memset(slotptr, 0x00, sizeof(dir_slot));