]> git.ipfire.org Git - people/ms/u-boot.git/blobdiff - fs/fat/fat.c
Merge git://git.denx.de/u-boot-sunxi
[people/ms/u-boot.git] / fs / fat / fat.c
index 465a6875edf509a17054adeefa6af73985543bdc..d16883fa10d4af14be4391c33944dbc7d2a65c13 100644 (file)
@@ -14,6 +14,7 @@
 #include <config.h>
 #include <exports.h>
 #include <fat.h>
+#include <fs.h>
 #include <asm/byteorder.h>
 #include <part.h>
 #include <malloc.h>
@@ -28,11 +29,13 @@ static const int vfat_enabled = 0;
 #endif
 
 /*
- * Convert a string to lowercase.
+ * Convert a string to lowercase.  Converts at most 'len' characters,
+ * 'len' may be larger than the length of 'str' if 'str' is NULL
+ * terminated.
  */
-static void downcase(char *str)
+static void downcase(char *str, size_t len)
 {
-       while (*str != '\0') {
+       while (*str != '\0' && len--) {
                *str = tolower(*str);
                str++;
        }
@@ -118,22 +121,6 @@ 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.
  */
@@ -146,10 +133,13 @@ static void get_name(dir_entry *dirent, char *s_name)
        ptr = s_name;
        while (*ptr && *ptr != ' ')
                ptr++;
+       if (dirent->lcase & CASE_LOWER_BASE)
+               downcase(s_name, (unsigned)(ptr - s_name));
        if (dirent->ext[0] && dirent->ext[0] != ' ') {
-               *ptr = '.';
-               ptr++;
+               *ptr++ = '.';
                memcpy(ptr, dirent->ext, 3);
+               if (dirent->lcase & CASE_LOWER_EXT)
+                       downcase(ptr, 3);
                ptr[3] = '\0';
                while (*ptr && *ptr != ' ')
                        ptr++;
@@ -159,7 +149,6 @@ static void get_name(dir_entry *dirent, char *s_name)
                *s_name = '\0';
        else if (*s_name == aRING)
                *s_name = DELETED_FLAG;
-       downcase(s_name);
 }
 
 static int flush_dirty_fat_buffer(fsdata *mydata);
@@ -268,8 +257,7 @@ get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
        int ret;
 
        if (clustnum > 0) {
-               startsect = mydata->data_begin +
-                               clustnum * mydata->clust_size;
+               startsect = clust_to_sect(mydata, clustnum);
        } else {
                startsect = mydata->rootdir_sect;
        }
@@ -468,95 +456,6 @@ 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 +472,13 @@ 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
@@ -752,7 +495,7 @@ read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
                return -1;
        }
 
-       block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
+       block = malloc_cache_aligned(cur_dev->blksz);
        if (block == NULL) {
                debug("Error: allocating block\n");
                return -1;
@@ -808,39 +551,19 @@ exit:
        return ret;
 }
 
-__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)
+static int get_fs_info(fsdata *mydata)
 {
-       char fnamecopy[2048];
        boot_sector bs;
        volume_info volinfo;
-       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 (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
+       int ret;
+
+       ret = read_bootsectandvi(&bs, &volinfo, &mydata->fatsize);
+       if (ret) {
                debug("Error: reading boot sector\n");
-               return -1;
+               return ret;
        }
 
        if (mydata->fatsize == 32) {
-               root_cluster = bs.root_cluster;
                mydata->fatlength = bs.fat32_length;
        } else {
                mydata->fatlength = bs.fat_length;
@@ -848,8 +571,7 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
 
        mydata->fat_sect = bs.reserved;
 
-       cursect = mydata->rootdir_sect
-               = mydata->fat_sect + mydata->fatlength * bs.fats;
+       mydata->rootdir_sect = mydata->fat_sect + mydata->fatlength * bs.fats;
 
        mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
        mydata->clust_size = bs.cluster_size;
@@ -862,19 +584,22 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
        if (mydata->fatsize == 32) {
                mydata->data_begin = mydata->rootdir_sect -
                                        (mydata->clust_size * 2);
+               mydata->root_cluster = bs.root_cluster;
        } else {
-               rootdir_size = ((bs.dir_entries[1]  * (int)256 +
-                                bs.dir_entries[0]) *
-                                sizeof(dir_entry)) /
-                                mydata->sect_size;
+               mydata->rootdir_size = ((bs.dir_entries[1]  * (int)256 +
+                                        bs.dir_entries[0]) *
+                                        sizeof(dir_entry)) /
+                                        mydata->sect_size;
                mydata->data_begin = mydata->rootdir_sect +
-                                       rootdir_size -
+                                       mydata->rootdir_size -
                                        (mydata->clust_size * 2);
+               mydata->root_cluster =
+                       sect_to_clust(mydata, mydata->rootdir_sect);
        }
 
        mydata->fatbufnum = -1;
        mydata->fat_dirty = 0;
-       mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
+       mydata->fatbuf = malloc_cache_aligned(FATBUFSIZE);
        if (mydata->fatbuf == NULL) {
                debug("Error: allocating memory\n");
                return -1;
@@ -887,355 +612,362 @@ int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
               mydata->fatsize, mydata->fat_sect, mydata->fatlength);
        debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
               "Data begins at: %d\n",
-              root_cluster,
+              mydata->root_cluster,
               mydata->rootdir_sect,
               mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
        debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
              mydata->clust_size);
 
-       /* "cwd" is always the root... */
-       while (ISDIRDELIM(*filename))
-               filename++;
+       return 0;
+}
 
-       /* 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;
+/*
+ * Directory iterator, to simplify filesystem traversal
+ *
+ * Implements an iterator pattern to traverse directory tables,
+ * transparently handling directory tables split across multiple
+ * clusters, and the difference between FAT12/FAT16 root directory
+ * (contiguous) and subdirectories + FAT32 root (chained).
+ *
+ * Rough usage:
+ *
+ *   for (fat_itr_root(&itr, fsdata); fat_itr_next(&itr); ) {
+ *      // to traverse down to a subdirectory pointed to by
+ *      // current iterator position:
+ *      fat_itr_child(&itr, &itr);
+ *   }
+ *
+ * For more complete example, see fat_itr_resolve()
+ */
 
-               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;
-       }
+typedef struct {
+       fsdata    *fsdata;        /* filesystem parameters */
+       unsigned   clust;         /* current cluster */
+       int        last_cluster;  /* set once we've read last cluster */
+       int        is_root;       /* is iterator at root directory */
+       int        remaining;     /* remaining dent's in current cluster */
 
-       buffer_blk_cnt = 0;
-       firsttime = 1;
-       while (1) {
-               int i;
+       /* current iterator position values: */
+       dir_entry *dent;          /* current directory entry */
+       char       l_name[VFAT_MAXLEN_BYTES];    /* long (vfat) name */
+       char       s_name[14];    /* short 8.3 name */
+       char      *name;          /* l_name if there is one, else s_name */
 
-               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);
-               }
+       /* storage for current cluster in memory: */
+       u8         block[MAX_CLUSTSIZE] __aligned(ARCH_DMA_MINALIGN);
+} fat_itr;
 
-               do_read = 1;
+static int fat_itr_isdir(fat_itr *itr);
 
-               if (mydata->fatsize == 32 && buffer_blk_cnt)
-                       do_read = 0;
+/**
+ * fat_itr_root() - initialize an iterator to start at the root
+ * directory
+ *
+ * @itr: iterator to initialize
+ * @fsdata: filesystem data for the partition
+ * @return 0 on success, else -errno
+ */
+static int fat_itr_root(fat_itr *itr, fsdata *fsdata)
+{
+       if (get_fs_info(fsdata))
+               return -ENXIO;
 
-               if (do_read) {
-                       read_blk = (mydata->fatsize == 32) ?
-                                   mydata->clust_size : PREFETCH_BLOCKS;
+       itr->fsdata = fsdata;
+       itr->clust = fsdata->root_cluster;
+       itr->dent = NULL;
+       itr->remaining = 0;
+       itr->last_cluster = 0;
+       itr->is_root = 1;
 
-                       debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
-                               cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
+       return 0;
+}
 
-                       if (disk_read(cursect, read_blk, dir_ptr) < 0) {
-                               debug("Error: reading rootdir block\n");
-                               goto exit;
-                       }
+/**
+ * fat_itr_child() - initialize an iterator to descend into a sub-
+ * directory
+ *
+ * Initializes 'itr' to iterate the contents of the directory at
+ * the current cursor position of 'parent'.  It is an error to
+ * call this if the current cursor of 'parent' is pointing at a
+ * regular file.
+ *
+ * Note that 'itr' and 'parent' can be the same pointer if you do
+ * not need to preserve 'parent' after this call, which is useful
+ * for traversing directory structure to resolve a file/directory.
+ *
+ * @itr: iterator to initialize
+ * @parent: the iterator pointing at a directory entry in the
+ *    parent directory of the directory to iterate
+ */
+static void fat_itr_child(fat_itr *itr, fat_itr *parent)
+{
+       fsdata *mydata = parent->fsdata;  /* for silly macros */
+       unsigned clustnum = START(parent->dent);
 
-                       dentptr = (dir_entry *)dir_ptr;
-               }
+       assert(fat_itr_isdir(parent));
 
-               for (i = 0; i < DIRENTSPERBLOCK; i++) {
-                       char s_name[14], l_name[VFAT_MAXLEN_BYTES];
-                       __u8 csum;
+       itr->fsdata = parent->fsdata;
+       if (clustnum > 0) {
+               itr->clust = clustnum;
+               itr->is_root = 0;
+       } else {
+               itr->clust = parent->fsdata->root_cluster;
+               itr->is_root = 1;
+       }
+       itr->dent = NULL;
+       itr->remaining = 0;
+       itr->last_cluster = 0;
+}
 
-                       l_name[0] = '\0';
-                       if (dentptr->name[0] == DELETED_FLAG) {
-                               dentptr++;
-                               continue;
-                       }
+static void *next_cluster(fat_itr *itr)
+{
+       fsdata *mydata = itr->fsdata;  /* for silly macros */
+       int ret;
+       u32 sect;
+
+       /* have we reached the end? */
+       if (itr->last_cluster)
+               return NULL;
+
+       sect = clust_to_sect(itr->fsdata, itr->clust);
+
+       debug("FAT read(sect=%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
+             sect, itr->fsdata->clust_size, DIRENTSPERBLOCK);
+
+       /*
+        * NOTE: do_fat_read_at() had complicated logic to deal w/
+        * vfat names that span multiple clusters in the fat16 case,
+        * which get_dentfromdir() probably also needed (and was
+        * missing).  And not entirely sure what fat32 didn't have
+        * the same issue..  We solve that by only caring about one
+        * dent at a time and iteratively constructing the vfat long
+        * name.
+        */
+       ret = disk_read(sect, itr->fsdata->clust_size,
+                       itr->block);
+       if (ret < 0) {
+               debug("Error: reading block\n");
+               return NULL;
+       }
 
-                       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;
-                       }
+       if (itr->is_root && itr->fsdata->fatsize != 32) {
+               itr->clust++;
+               sect = clust_to_sect(itr->fsdata, itr->clust);
+               if (sect - itr->fsdata->rootdir_sect >=
+                   itr->fsdata->rootdir_size) {
+                       debug("cursect: 0x%x\n", itr->clust);
+                       itr->last_cluster = 1;
+               }
+       } else {
+               itr->clust = get_fatent(itr->fsdata, itr->clust);
+               if (CHECK_CLUST(itr->clust, itr->fsdata->fatsize)) {
+                       debug("cursect: 0x%x\n", itr->clust);
+                       itr->last_cluster = 1;
+               }
+       }
 
-                       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;
-                       }
+       return itr->block;
+}
 
-                       if (strcmp(fnamecopy, s_name)
-                           && strcmp(fnamecopy, l_name)) {
-                               debug("RootMismatch: |%s|%s|\n", s_name,
-                                      l_name);
-                               dentptr++;
-                               continue;
-                       }
+static dir_entry *next_dent(fat_itr *itr)
+{
+       if (itr->remaining == 0) {
+               struct dir_entry *dent = next_cluster(itr);
+               unsigned nbytes = itr->fsdata->sect_size *
+                       itr->fsdata->clust_size;
 
-                       if (isdir && !(dentptr->attr & ATTR_DIR))
-                               goto exit;
+               /* have we reached the last cluster? */
+               if (!dent)
+                       return NULL;
 
-                       debug("RootName: %s", s_name);
-                       debug(", start: 0x%x", START(dentptr));
-                       debug(", size:  0x%x %s\n",
-                              FAT2CPU32(dentptr->size),
-                              isdir ? "(DIR)" : "");
+               itr->remaining = nbytes / sizeof(dir_entry) - 1;
+               itr->dent = dent;
+       } else {
+               itr->remaining--;
+               itr->dent++;
+       }
 
-                       goto rootdir_done;      /* We got a match */
-               }
-               debug("END LOOP: buffer_blk_cnt=%d   clust_size=%d\n", buffer_blk_cnt,
-                      mydata->clust_size);
+       /* have we reached the last valid entry? */
+       if (itr->dent->name[0] == 0)
+               return NULL;
 
-               /*
-                * 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;
+       return itr->dent;
+}
 
-                               nxt_clust = get_fatent(mydata, root_cluster);
-                               rootdir_end = CHECK_CLUST(nxt_clust, 32);
+static dir_entry *extract_vfat_name(fat_itr *itr)
+{
+       struct dir_entry *dent = itr->dent;
+       int seqn = itr->dent->name[0] & ~LAST_LONG_ENTRY_MASK;
+       u8 chksum, alias_checksum = ((dir_slot *)dent)->alias_checksum;
+       int n = 0;
 
-                               nxtsect = mydata->data_begin +
-                                       (nxt_clust * mydata->clust_size);
+       while (seqn--) {
+               char buf[13];
+               int idx = 0;
 
-                               root_cluster = nxt_clust;
+               slot2str((dir_slot *)dent, buf, &idx);
 
-                               cursect = nxtsect;
-                               buffer_blk_cnt = 0;
-                       }
-               } else {
-                       if (buffer_blk_cnt == PREFETCH_BLOCKS)
-                               buffer_blk_cnt = 0;
+               /* shift accumulated long-name up and copy new part in: */
+               memmove(itr->l_name + idx, itr->l_name, n);
+               memcpy(itr->l_name, buf, idx);
+               n += idx;
 
-                       rootdir_end = (++cursect - mydata->rootdir_sect >=
-                                      rootdir_size);
-               }
+               dent = next_dent(itr);
+               if (!dent)
+                       return NULL;
+       }
 
-               /* 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;
-               }
+       itr->l_name[n] = '\0';
+
+       chksum = mkcksum(dent->name, dent->ext);
+
+       /* checksum mismatch could mean deleted file, etc.. skip it: */
+       if (chksum != alias_checksum) {
+               debug("** chksum=%x, alias_checksum=%x, l_name=%s, s_name=%8s.%3s\n",
+                     chksum, alias_checksum, itr->l_name, dent->name, dent->ext);
+               return NULL;
        }
-rootdir_done:
 
-       firsttime = 1;
+       return dent;
+}
 
-       while (isdir) {
-               int startsect = mydata->data_begin
-                       + START(dentptr) * mydata->clust_size;
-               dir_entry dent;
-               char *nextname = NULL;
+/**
+ * fat_itr_next() - step to the next entry in a directory
+ *
+ * Must be called once on a new iterator before the cursor is valid.
+ *
+ * @itr: the iterator to iterate
+ * @return boolean, 1 if success or 0 if no more entries in the
+ *    current directory
+ */
+static int fat_itr_next(fat_itr *itr)
+{
+       dir_entry *dent;
 
-               dent = *dentptr;
-               dentptr = &dent;
+       itr->name = NULL;
 
-               idx = dirdelim(subname);
+       while (1) {
+               dent = next_dent(itr);
+               if (!dent)
+                       return 0;
 
-               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;
+               if (dent->name[0] == DELETED_FLAG ||
+                   dent->name[0] == aRING)
+                       continue;
+
+               if (dent->attr & ATTR_VOLUME) {
+                       if (vfat_enabled &&
+                           (dent->attr & ATTR_VFAT) == ATTR_VFAT &&
+                           (dent->name[0] & LAST_LONG_ENTRY_MASK)) {
+                               dent = extract_vfat_name(itr);
+                               if (!dent)
+                                       continue;
+                               itr->name = itr->l_name;
+                               break;
                        } else {
-                               isdir = 0;
+                               /* Volume label or VFAT entry, skip */
+                               continue;
                        }
                }
 
-               if (get_dentfromdir(mydata, startsect, subname, dentptr,
-                                    isdir ? 0 : dols) == NULL) {
-                       if (dols && !isdir)
-                               *size = 0;
-                       goto exit;
-               }
+               break;
+       }
 
-               if (isdir && !(dentptr->attr & ATTR_DIR))
-                       goto exit;
+       get_name(dent, itr->s_name);
+       if (!itr->name)
+               itr->name = itr->s_name;
 
-               /*
-                * 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;
-               }
+       return 1;
+}
 
-               if (idx >= 0)
-                       subname = nextname;
-       }
+/**
+ * fat_itr_isdir() - is current cursor position pointing to a directory
+ *
+ * @itr: the iterator
+ * @return true if cursor is at a directory
+ */
+static int fat_itr_isdir(fat_itr *itr)
+{
+       return !!(itr->dent->attr & ATTR_DIR);
+}
 
-       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);
+/*
+ * Helpers:
+ */
 
-exit:
-       free(mydata->fatbuf);
-       return ret;
-}
+#define TYPE_FILE 0x1
+#define TYPE_DIR  0x2
+#define TYPE_ANY  (TYPE_FILE | TYPE_DIR)
 
-int do_fat_read(const char *filename, void *buffer, loff_t maxsize, int dols,
-               loff_t *actread)
+/**
+ * fat_itr_resolve() - traverse directory structure to resolve the
+ * requested path.
+ *
+ * Traverse directory structure to the requested path.  If the specified
+ * path is to a directory, this will descend into the directory and
+ * leave it iterator at the start of the directory.  If the path is to a
+ * file, it will leave the iterator in the parent directory with current
+ * cursor at file's entry in the directory.
+ *
+ * @itr: iterator initialized to root
+ * @path: the requested path
+ * @type: bitmask of allowable file types
+ * @return 0 on success or -errno
+ */
+static int fat_itr_resolve(fat_itr *itr, const char *path, unsigned type)
 {
-       return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, actread);
+       const char *next;
+
+       /* chomp any extra leading slashes: */
+       while (path[0] && ISDIRDELIM(path[0]))
+               path++;
+
+       /* are we at the end? */
+       if (strlen(path) == 0) {
+               if (!(type & TYPE_DIR))
+                       return -ENOENT;
+               return 0;
+       }
+
+       /* find length of next path entry: */
+       next = path;
+       while (next[0] && !ISDIRDELIM(next[0]))
+               next++;
+
+       while (fat_itr_next(itr)) {
+               int match = 0;
+               unsigned n = max(strlen(itr->name), (size_t)(next - path));
+
+               /* check both long and short name: */
+               if (!strncasecmp(path, itr->name, n))
+                       match = 1;
+               else if (itr->name != itr->s_name &&
+                        !strncasecmp(path, itr->s_name, n))
+                       match = 1;
+
+               if (!match)
+                       continue;
+
+               if (fat_itr_isdir(itr)) {
+                       /* recurse into directory: */
+                       fat_itr_child(itr, itr);
+                       return fat_itr_resolve(itr, next, type);
+               } else if (next[0]) {
+                       /*
+                        * If next is not empty then we have a case
+                        * like: /path/to/realfile/nonsense
+                        */
+                       debug("bad trailing path: %s\n", next);
+                       return -ENOENT;
+               } else if (!(type & TYPE_FILE)) {
+                       return -ENOTDIR;
+               } else {
+                       return 0;
+               }
+       }
+
+       return -ENOENT;
 }
 
 int file_fat_detectfs(void)
@@ -1300,33 +1032,88 @@ int file_fat_detectfs(void)
        return 0;
 }
 
-int file_fat_ls(const char *dir)
-{
-       loff_t size;
-
-       return do_fat_read(dir, NULL, 0, LS_YES, &size);
-}
-
 int fat_exists(const char *filename)
 {
+       fsdata fsdata;
+       fat_itr *itr;
        int ret;
-       loff_t size;
 
-       ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
+       itr = malloc_cache_aligned(sizeof(fat_itr));
+       if (!itr)
+               return 0;
+       ret = fat_itr_root(itr, &fsdata);
+       if (ret)
+               goto out;
+
+       ret = fat_itr_resolve(itr, filename, TYPE_ANY);
+       free(fsdata.fatbuf);
+out:
+       free(itr);
        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 *itr;
+       int ret;
+
+       itr = malloc_cache_aligned(sizeof(fat_itr));
+       if (!itr)
+               return -ENOMEM;
+       ret = fat_itr_root(itr, &fsdata);
+       if (ret)
+               goto out_free_itr;
+
+       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:
+                */
+               free(fsdata.fatbuf);
+               fat_itr_root(itr, &fsdata);
+               if (!fat_itr_resolve(itr, filename, TYPE_DIR)) {
+                       *size = 0;
+                       ret = 0;
+               }
+               goto out_free_both;
+       }
+
+       *size = FAT2CPU32(itr->dent->size);
+out_free_both:
+       free(fsdata.fatbuf);
+out_free_itr:
+       free(itr);
+       return ret;
 }
 
 int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
                     loff_t maxsize, loff_t *actread)
 {
+       fsdata fsdata;
+       fat_itr *itr;
+       int ret;
+
+       itr = malloc_cache_aligned(sizeof(fat_itr));
+       if (!itr)
+               return -ENOMEM;
+       ret = fat_itr_root(itr, &fsdata);
+       if (ret)
+               goto out_free_itr;
+
+       ret = fat_itr_resolve(itr, filename, TYPE_FILE);
+       if (ret)
+               goto out_free_both;
+
        printf("reading %s\n", filename);
-       return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0,
-                             actread);
+       ret = get_contents(&fsdata, itr->dent, pos, buffer, maxsize, actread);
+
+out_free_both:
+       free(fsdata.fatbuf);
+out_free_itr:
+       free(itr);
+       return ret;
 }
 
 int file_fat_read(const char *filename, void *buffer, int maxsize)
@@ -1353,6 +1140,71 @@ int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
        return ret;
 }
 
+typedef struct {
+       struct fs_dir_stream parent;
+       struct fs_dirent dirent;
+       fsdata fsdata;
+       fat_itr itr;
+} fat_dir;
+
+int fat_opendir(const char *filename, struct fs_dir_stream **dirsp)
+{
+       fat_dir *dir;
+       int ret;
+
+       dir = malloc_cache_aligned(sizeof(*dir));
+       if (!dir)
+               return -ENOMEM;
+       memset(dir, 0, sizeof(*dir));
+
+       ret = fat_itr_root(&dir->itr, &dir->fsdata);
+       if (ret)
+               goto fail_free_dir;
+
+       ret = fat_itr_resolve(&dir->itr, filename, TYPE_DIR);
+       if (ret)
+               goto fail_free_both;
+
+       *dirsp = (struct fs_dir_stream *)dir;
+       return 0;
+
+fail_free_both:
+       free(dir->fsdata.fatbuf);
+fail_free_dir:
+       free(dir);
+       return ret;
+}
+
+int fat_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp)
+{
+       fat_dir *dir = (fat_dir *)dirs;
+       struct fs_dirent *dent = &dir->dirent;
+
+       if (!fat_itr_next(&dir->itr))
+               return -ENOENT;
+
+       memset(dent, 0, sizeof(*dent));
+       strcpy(dent->name, dir->itr.name);
+
+       if (fat_itr_isdir(&dir->itr)) {
+               dent->type = FS_DT_DIR;
+       } else {
+               dent->type = FS_DT_REG;
+               dent->size = FAT2CPU32(dir->itr.dent->size);
+       }
+
+       *dentp = dent;
+
+       return 0;
+}
+
+void fat_closedir(struct fs_dir_stream *dirs)
+{
+       fat_dir *dir = (fat_dir *)dirs;
+       free(dir->fsdata.fatbuf);
+       free(dir);
+}
+
 void fat_close(void)
 {
 }