[U-Boot] [PATCH v2 3/8] fat/fs: convert to directory iterators

Rob Clark
2017-09-02T16:37:58Z

And drop a whole lot of ugly code!

Signed-off-by: Rob Clark <robdclark@gmail.com>
---
fs/fat/fat.c | 723 ++++++----------------------------------------------------
include/fat.h | 6 -
2 files changed, 75 insertions(+), 654 deletions(-)

diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index c72d6ca931..3193290434 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -119,22 +119,6 @@ int fat_register_device(struct blk_desc *dev_desc, int part_no)
}

/*
- * 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.
*/
static void get_name(dir_entry *dirent, char *s_name)
@@ -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])
{
@@ -572,170 +467,11 @@ static __u8 mkcksum(const char name[8], const char ext[3])
return ret;
}

-/*
- * Get the directory entry associated with 'filename' from the directory
- * starting at 'startsect'
- */
+// These should probably DIAF..
__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
@@ -877,374 +613,6 @@ 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
@@ -1571,12 +939,6 @@ 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;
@@ -1641,31 +1003,96 @@ 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;
+
+ 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 do_fat_read(dir, NULL, 0, LS_YES, &size);
+ 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 ret;
+
+ 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)
diff --git a/include/fat.h b/include/fat.h
index 6d3fc8e4a6..3e7ab9ea8d 100644
--- a/include/fat.h
+++ b/include/fat.h
@@ -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)
--
2.13.5