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fat/fs: convert to directory iterators

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And drop a whole lot of ugly code!

Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Łukasz Majewski <lukma@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Rob Clark 2017-09-09 13:15:54 -04:00 committed by Tom Rini
parent c6e3baa565
commit 8eafae209c
2 changed files with 76 additions and 652 deletions
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722
fs/fat/fat.c
View File

@ -118,22 +118,6 @@ int fat_register_device(struct blk_desc *dev_desc, int part_no)
return fat_set_blk_dev(dev_desc, &info);
}
/*
* Get the first occurence of a directory delimiter ('/' or '\') in a string.
* Return index into string if found, -1 otherwise.
*/
static int dirdelim(char *str)
{
char *start = str;
while (*str != '\0') {
if (ISDIRDELIM(*str))
return str - start;
str++;
}
return -1;
}
/*
* Extract zero terminated short name from a directory entry.
*/
@ -468,95 +452,6 @@ static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
return 0;
}
/*
* Extract the full long filename starting at 'retdent' (which is really
* a slot) into 'l_name'. If successful also copy the real directory entry
* into 'retdent'
* Return 0 on success, -1 otherwise.
*/
static int
get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
dir_entry *retdent, char *l_name)
{
dir_entry *realdent;
dir_slot *slotptr = (dir_slot *)retdent;
__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
PREFETCH_BLOCKS :
mydata->clust_size);
__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
int idx = 0;
if (counter > VFAT_MAXSEQ) {
debug("Error: VFAT name is too long\n");
return -1;
}
while ((__u8 *)slotptr < buflimit) {
if (counter == 0)
break;
if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
return -1;
slotptr++;
counter--;
}
if ((__u8 *)slotptr >= buflimit) {
dir_slot *slotptr2;
if (curclust == 0)
return -1;
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return -1;
}
if (get_cluster(mydata, curclust, get_contents_vfatname_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return -1;
}
slotptr2 = (dir_slot *)get_contents_vfatname_block;
while (counter > 0) {
if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
& 0xff) != counter)
return -1;
slotptr2++;
counter--;
}
/* Save the real directory entry */
realdent = (dir_entry *)slotptr2;
while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
slotptr2--;
slot2str(slotptr2, l_name, &idx);
}
} else {
/* Save the real directory entry */
realdent = (dir_entry *)slotptr;
}
do {
slotptr--;
if (slot2str(slotptr, l_name, &idx))
break;
} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
l_name[idx] = '\0';
if (*l_name == DELETED_FLAG)
*l_name = '\0';
else if (*l_name == aRING)
*l_name = DELETED_FLAG;
downcase(l_name);
/* Return the real directory entry */
memcpy(retdent, realdent, sizeof(dir_entry));
return 0;
}
/* Calculate short name checksum */
static __u8 mkcksum(const char name[8], const char ext[3])
{
@ -573,169 +468,13 @@ static __u8 mkcksum(const char name[8], const char ext[3])
}
/*
* Get the directory entry associated with 'filename' from the directory
* starting at 'startsect'
* TODO these should go away once fat_write is reworked to use the
* directory iterator
*/
__u8 get_dentfromdir_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
char *filename, dir_entry *retdent,
int dols)
{
__u16 prevcksum = 0xffff;
__u32 curclust = START(retdent);
int files = 0, dirs = 0;
debug("get_dentfromdir: %s\n", filename);
while (1) {
dir_entry *dentptr;
int i;
if (get_cluster(mydata, curclust, get_dentfromdir_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return NULL;
}
dentptr = (dir_entry *)get_dentfromdir_block;
for (i = 0; i < DIRENTSPERCLUST; i++) {
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
l_name[0] = '\0';
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if ((dentptr->attr & ATTR_VOLUME)) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum = ((dir_slot *)dentptr)->alias_checksum;
get_vfatname(mydata, curclust,
get_dentfromdir_block,
dentptr, l_name);
if (dols) {
int isdir;
char dirc;
int doit = 0;
isdir = (dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("vfatname: |%s|\n", l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
}
if (dentptr->name[0] == 0) {
if (dols) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
}
debug("Dentname == NULL - %d\n", i);
return NULL;
}
if (vfat_enabled) {
__u8 csum = mkcksum(dentptr->name, dentptr->ext);
if (dols && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
}
get_name(dentptr, s_name);
if (dols) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(filename, s_name)
&& strcmp(filename, l_name)) {
debug("Mismatch: |%s|%s|\n", s_name, l_name);
dentptr++;
continue;
}
memcpy(retdent, dentptr, sizeof(dir_entry));
debug("DentName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
(dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
return retdent;
}
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return NULL;
}
}
return NULL;
}
__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
/*
* Read boot sector and volume info from a FAT filesystem
@ -879,374 +618,6 @@ static int get_fs_info(fsdata *mydata)
return 0;
}
__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, int dols, int dogetsize, loff_t *size)
{
char fnamecopy[2048];
fsdata datablock;
fsdata *mydata = &datablock;
dir_entry *dentptr = NULL;
__u16 prevcksum = 0xffff;
char *subname = "";
__u32 cursect;
int idx, isdir = 0;
int files = 0, dirs = 0;
int ret = -1;
int firsttime;
__u32 root_cluster = 0;
__u32 read_blk;
int rootdir_size = 0;
int buffer_blk_cnt;
int do_read;
__u8 *dir_ptr;
if (get_fs_info(mydata))
return -1;
cursect = mydata->rootdir_sect;
/* "cwd" is always the root... */
while (ISDIRDELIM(*filename))
filename++;
/* Make a copy of the filename and convert it to lowercase */
strcpy(fnamecopy, filename);
downcase(fnamecopy);
root_reparse:
if (*fnamecopy == '\0') {
if (!dols)
goto exit;
dols = LS_ROOT;
} else if ((idx = dirdelim(fnamecopy)) >= 0) {
isdir = 1;
fnamecopy[idx] = '\0';
subname = fnamecopy + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*subname))
subname++;
} else if (dols) {
isdir = 1;
}
buffer_blk_cnt = 0;
firsttime = 1;
while (1) {
int i;
if (mydata->fatsize == 32 || firsttime) {
dir_ptr = do_fat_read_at_block;
firsttime = 0;
} else {
/**
* FAT16 sector buffer modification:
* Each loop, the second buffered block is moved to
* the buffer begin, and two next sectors are read
* next to the previously moved one. So the sector
* buffer keeps always 3 sectors for fat16.
* And the current sector is the buffer second sector
* beside the "firsttime" read, when it is the first one.
*
* PREFETCH_BLOCKS is 2 for FAT16 == loop[0:1]
* n = computed root dir sector
* loop | cursect-1 | cursect | cursect+1 |
* 0 | sector n+0 | sector n+1 | none |
* 1 | none | sector n+0 | sector n+1 |
* 0 | sector n+1 | sector n+2 | sector n+3 |
* 1 | sector n+3 | ...
*/
dir_ptr = (do_fat_read_at_block + mydata->sect_size);
memcpy(do_fat_read_at_block, dir_ptr, mydata->sect_size);
}
do_read = 1;
if (mydata->fatsize == 32 && buffer_blk_cnt)
do_read = 0;
if (do_read) {
read_blk = (mydata->fatsize == 32) ?
mydata->clust_size : PREFETCH_BLOCKS;
debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
if (disk_read(cursect, read_blk, dir_ptr) < 0) {
debug("Error: reading rootdir block\n");
goto exit;
}
dentptr = (dir_entry *)dir_ptr;
}
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 (vfat_enabled)
csum = mkcksum(dentptr->name, dentptr->ext);
if (dentptr->attr & ATTR_VOLUME) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum =
((dir_slot *)dentptr)->alias_checksum;
get_vfatname(mydata,
root_cluster,
dir_ptr,
dentptr, l_name);
if (dols == LS_ROOT) {
char dirc;
int doit = 0;
int isdir =
(dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("Rootvfatname: |%s|\n",
l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
} else if (dentptr->name[0] == 0) {
debug("RootDentname == NULL - %d\n", i);
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
ret = 0;
}
goto exit;
}
else if (vfat_enabled &&
dols == LS_ROOT && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
get_name(dentptr, s_name);
if (dols == LS_ROOT) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirc = '/';
if (s_name[0] != 0) {
dirs++;
doit = 1;
}
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(fnamecopy, s_name)
&& strcmp(fnamecopy, l_name)) {
debug("RootMismatch: |%s|%s|\n", s_name,
l_name);
dentptr++;
continue;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
debug("RootName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
isdir ? "(DIR)" : "");
goto rootdir_done; /* We got a match */
}
debug("END LOOP: buffer_blk_cnt=%d clust_size=%d\n", buffer_blk_cnt,
mydata->clust_size);
/*
* On FAT32 we must fetch the FAT entries for the next
* root directory clusters when a cluster has been
* completely processed.
*/
++buffer_blk_cnt;
int rootdir_end = 0;
if (mydata->fatsize == 32) {
if (buffer_blk_cnt == mydata->clust_size) {
int nxtsect = 0;
int nxt_clust = 0;
nxt_clust = get_fatent(mydata, root_cluster);
rootdir_end = CHECK_CLUST(nxt_clust, 32);
nxtsect = mydata->data_begin +
(nxt_clust * mydata->clust_size);
root_cluster = nxt_clust;
cursect = nxtsect;
buffer_blk_cnt = 0;
}
} else {
if (buffer_blk_cnt == PREFETCH_BLOCKS)
buffer_blk_cnt = 0;
rootdir_end = (++cursect - mydata->rootdir_sect >=
rootdir_size);
}
/* If end of rootdir reached */
if (rootdir_end) {
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
*size = 0;
}
goto exit;
}
}
rootdir_done:
firsttime = 1;
while (isdir) {
int startsect = mydata->data_begin
+ START(dentptr) * mydata->clust_size;
dir_entry dent;
char *nextname = NULL;
dent = *dentptr;
dentptr = &dent;
idx = dirdelim(subname);
if (idx >= 0) {
subname[idx] = '\0';
nextname = subname + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*nextname))
nextname++;
if (dols && *nextname == '\0')
firsttime = 0;
} else {
if (dols && firsttime) {
firsttime = 0;
} else {
isdir = 0;
}
}
if (get_dentfromdir(mydata, startsect, subname, dentptr,
isdir ? 0 : dols) == NULL) {
if (dols && !isdir)
*size = 0;
goto exit;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
/*
* If we are looking for a directory, and found a directory
* type entry, and the entry is for the root directory (as
* denoted by a cluster number of 0), jump back to the start
* of the function, since at least on FAT12/16, the root dir
* lives in a hard-coded location and needs special handling
* to parse, rather than simply following the cluster linked
* list in the FAT, like other directories.
*/
if (isdir && (dentptr->attr & ATTR_DIR) && !START(dentptr)) {
/*
* Modify the filename to remove the prefix that gets
* back to the root directory, so the initial root dir
* parsing code can continue from where we are without
* confusion.
*/
strcpy(fnamecopy, nextname ?: "");
/*
* Set up state the same way as the function does when
* first started. This is required for the root dir
* parsing code operates in its expected environment.
*/
subname = "";
cursect = mydata->rootdir_sect;
isdir = 0;
goto root_reparse;
}
if (idx >= 0)
subname = nextname;
}
if (dogetsize) {
*size = FAT2CPU32(dentptr->size);
ret = 0;
} else {
ret = get_contents(mydata, dentptr, pos, buffer, maxsize, size);
}
debug("Size: %u, got: %llu\n", FAT2CPU32(dentptr->size), *size);
exit:
free(mydata->fatbuf);
return ret;
}
/*
* Directory iterator, to simplify filesystem traversal
@ -1595,12 +966,6 @@ static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
return -ENOENT;
}
int do_fat_read(const char *filename, void *buffer, loff_t maxsize, int dols,
loff_t *actread)
{
return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, actread);
}
int file_fat_detectfs(void)
{
boot_sector bs;
@ -1665,31 +1030,96 @@ int file_fat_detectfs(void)
int file_fat_ls(const char *dir)
{
loff_t size;
fsdata fsdata;
fat_itr itrblock, *itr = &itrblock;
int files = 0, dirs = 0;
int ret;
return do_fat_read(dir, NULL, 0, LS_YES, &size);
ret = fat_itr_root(itr, &fsdata);
if (ret)
return ret;
ret = fat_itr_resolve(itr, dir, TYPE_DIR);
if (ret)
return ret;
while (fat_itr_next(itr)) {
if (fat_itr_isdir(itr)) {
printf(" %s/\n", itr->name);
dirs++;
} else {
printf(" %8u %s\n",
FAT2CPU32(itr->dent->size),
itr->name);
files++;
}
}
printf("\n%d file(s), %d dir(s)\n\n", files, dirs);
return 0;
}
int fat_exists(const char *filename)
{
fsdata fsdata;
fat_itr itrblock, *itr = &itrblock;
int ret;
loff_t size;
ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
ret = fat_itr_root(itr, &fsdata);
if (ret)
return 0;
ret = fat_itr_resolve(itr, filename, TYPE_ANY);
return ret == 0;
}
int fat_size(const char *filename, loff_t *size)
{
return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, size);
fsdata fsdata;
fat_itr itrblock, *itr = &itrblock;
int ret;
ret = fat_itr_root(itr, &fsdata);
if (ret)
return ret;
ret = fat_itr_resolve(itr, filename, TYPE_FILE);
if (ret) {
/*
* Directories don't have size, but fs_size() is not
* expected to fail if passed a directory path:
*/
fat_itr_root(itr, &fsdata);
if (!fat_itr_resolve(itr, filename, TYPE_DIR)) {
*size = 0;
return 0;
}
return ret;
}
*size = FAT2CPU32(itr->dent->size);
return 0;
}
int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread)
{
fsdata fsdata;
fat_itr itrblock, *itr = &itrblock;
int ret;
ret = fat_itr_root(itr, &fsdata);
if (ret)
return ret;
ret = fat_itr_resolve(itr, filename, TYPE_FILE);
if (ret)
return ret;
printf("reading %s\n", filename);
return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0,
actread);
return get_contents(&fsdata, itr->dent, pos, buffer, maxsize, actread);
}
int file_fat_read(const char *filename, void *buffer, int maxsize)

6
include/fat.h
View File

@ -58,12 +58,6 @@
*/
#define LAST_LONG_ENTRY_MASK 0x40
/* Flags telling whether we should read a file or list a directory */
#define LS_NO 0
#define LS_YES 1
#define LS_DIR 1
#define LS_ROOT 2
#define ISDIRDELIM(c) ((c) == '/' || (c) == '\\')
#define FSTYPE_NONE (-1)