altos: Make sure FAT cluster allocation works for size zero files
[fw/altos] / src / drivers / ao_fat.c
index 7d9bcd810321abcb01b914499da54b128c47d612..3c72c397e7befeede0fa28d38f56e82bca93b882 100644 (file)
 #include "ao_fat.h"
 #include "ao_bufio.h"
 
+/* Include FAT commands */
+#ifndef AO_FAT_TEST
+#define FAT_COMMANDS   1
+#endif
+
+/* Spew FAT tracing */
+#define FAT_TRACE      0
+#ifdef DBG
+#undef DBG
+#endif
+
+#if FAT_TRACE
+#define DBG(...) printf(__VA_ARGS__)
+#else
+#define DBG(...)
+#endif
+
 /*
  * Basic file system types
  */
@@ -268,101 +286,130 @@ ao_fat_cluster_seek(cluster_t cluster, cluster_t distance)
 static cluster_t
 ao_fat_cluster_set_size(cluster_t first_cluster, cluster_t size)
 {
-       cluster_t       clear_cluster = 0;
+       cluster_t       have;
+       cluster_t       last_cluster;
+       cluster_t       next_cluster;
+
+       /* Walk the cluster chain to the
+        * spot where it needs to change. That
+        * will either be the end of the chain (in case it needs to grow),
+        * or after the desired number of clusters, in which case it needs to shrink
+        */
+       next_cluster = first_cluster;
+       last_cluster = 0;
+       DBG("\tclusters:");
+       for (have = 0; have < size; have++) {
+               DBG(" %08x", next_cluster);
+               if (!ao_fat_cluster_valid(next_cluster))
+                       break;
+               last_cluster = next_cluster;
+               next_cluster = ao_fat_entry_read(next_cluster);
+       }
+       DBG("\n");
+
+       /* At this point, last_cluster points to the last valid
+        * cluster in the file, if any. That's the spot in the FAT
+        * that needs to be rewritten, either to truncate the file by
+        * writing an END marker, or to extend the file by writing
+        * more clusters. next_cluster will contain the value of the
+        * FAT at last_cluster.
+        *
+        * If this is at the head of the cluster chain, then
+        * last_cluster will be zero and next_cluster will
+        * be the first cluster in the chain.
+        */
+       if (have == size) {
+               /* The file is large enough, truncate as needed */
+               if (ao_fat_cluster_valid(next_cluster)) {
+                       DBG("truncate between %08x and %08x\n", last_cluster, next_cluster);
+                       if (last_cluster)
+                               /*
+                                * Otherwise, rewrite the last cluster
+                                * in the chain with a LAST marker
+                                */
+                               (void) ao_fat_entry_replace(last_cluster,
+                                                           AO_FAT_LAST_CLUSTER);
+                       else
+                               /*
+                                * If the file is getting erased, then
+                                * rewrite the directory entry cluster
+                                * value
+                                */
+                               first_cluster = 0;
 
-       if (size == 0) {
-               clear_cluster = first_cluster;
-               first_cluster = 0;
-       } else {
-               cluster_t       have;
-               cluster_t       last_cluster = 0;
-               cluster_t       next_cluster;
-
-               /* Walk the cluster chain to the
-                * spot where it needs to change. That
-                * will either be the end of the chain (in case it needs to grow),
-                * or after the desired number of clusters, in which case it needs to shrink
-                */
-               next_cluster = first_cluster;
-               for (have = 0; have < size; have++) {
-                       last_cluster = next_cluster;
-                       next_cluster = ao_fat_entry_read(last_cluster);
-                       if (!ao_fat_cluster_valid(next_cluster))
-                               break;
-               }
+                       /* Clear the remaining clusters in the chain */
+                       ao_fat_free_cluster_chain(next_cluster);
 
-               if (have == size) {
-                       /* The file is large enough, truncate as needed */
-                       if (ao_fat_cluster_valid(next_cluster)) {
-                               /* Rewrite that cluster entry with 0xffff to mark the end of the chain */
-                               clear_cluster = ao_fat_entry_replace(last_cluster, AO_FAT_LAST_CLUSTER);
-                               filesystem_full = 0;
-                       } else {
-                               /* The chain is already the right length, don't mess with it */
-                               ;
-                       }
+                       /* The file system is no longer full (if it was) */
+                       filesystem_full = 0;
                } else {
-                       cluster_t       need;
-                       cluster_t       free;
+                       DBG("unchanged FAT chain\n");
+                       /* The chain is already the right length, don't mess with it */
+                       ;
+               }
+       } else {
+               cluster_t       need;
+               cluster_t       free;
 
-                       if (filesystem_full)
-                               return AO_FAT_BAD_CLUSTER;
+               if (filesystem_full)
+                       return AO_FAT_BAD_CLUSTER;
 
-                       if (next_free < 2 || number_cluster <= next_free) {
-                               next_free = 2;
-                               fsinfo_dirty = 1;
-                       }
+               /* Set next_free if it has wrapped or wasn't set before */
+               if (next_free < 2 || number_cluster <= next_free) {
+                       next_free = 2;
+                       fsinfo_dirty = 1;
+               }
 
-                       /* See if there are enough free clusters in the file system */
-                       need = size - have;
+               /* See if there are enough free clusters in the file system */
+               need = size - have;
 
 #define loop_cluster   for (free = next_free; need > 0;)
-#define next_cluster                                   \
-                       if (++free == number_cluster)   \
-                               free = 2;               \
-                       if (free == next_free) \
-                               break;                  \
-
-                       loop_cluster {
-                               if (!ao_fat_entry_read(free))
-                                       need--;
-                               next_cluster;
-                       }
-                       /* Still need some, tell the user that we've failed */
-                       if (need) {
-                               filesystem_full = 1;
-                               return AO_FAT_BAD_CLUSTER;
-                       }
+#define next_cluster                           \
+               if (++free == number_cluster)   \
+                       free = 2;               \
+               if (free == next_free)          \
+                       break;                  \
+
+               loop_cluster {
+                       if (!ao_fat_entry_read(free))
+                               need--;
+                       next_cluster;
+               }
 
-                       /* Now go allocate those clusters and
-                        * thread them onto the chain
-                        */
-                       need = size - have;
-                       loop_cluster {
-                               if (!ao_fat_entry_read(free)) {
-                                       next_free = free + 1;
-                                       if (next_free >= number_cluster)
-                                               next_free = 2;
-                                       fsinfo_dirty = 1;
-                                       if (last_cluster)
-                                               ao_fat_entry_replace(last_cluster, free);
-                                       else
-                                               first_cluster = free;
-                                       last_cluster = free;
-                                       need--;
-                               }
-                               next_cluster;
+               /* Still need some, tell the user that we've failed */
+               if (need) {
+                       filesystem_full = 1;
+                       return AO_FAT_BAD_CLUSTER;
+               }
+
+               /* Now go allocate those clusters and
+                * thread them onto the chain
+                */
+               need = size - have;
+               loop_cluster {
+                       if (ao_fat_entry_read(free) == 0) {
+                               next_free = free + 1;
+                               if (next_free >= number_cluster)
+                                       next_free = 2;
+                               fsinfo_dirty = 1;
+                               DBG("\tadd cluster. old %08x new %08x\n", last_cluster, free);
+                               if (last_cluster)
+                                       ao_fat_entry_replace(last_cluster, free);
+                               else
+                                       first_cluster = free;
+                               last_cluster = free;
+                               need--;
                        }
+                       next_cluster;
+               }
 #undef loop_cluster
 #undef next_cluster
-                       /* Mark the new end of the chain */
-                       ao_fat_entry_replace(last_cluster, AO_FAT_LAST_CLUSTER);
-               }
+               DBG("\tlast cluster %08x\n", last_cluster);
+               /* Mark the new end of the chain */
+               ao_fat_entry_replace(last_cluster, AO_FAT_LAST_CLUSTER);
        }
 
-       /* Deallocate clusters off the end of the file */
-       if (ao_fat_cluster_valid(clear_cluster))
-               ao_fat_free_cluster_chain(clear_cluster);
+       DBG("\tfirst cluster %08x\n", first_cluster);
        return first_cluster;
 }
 
@@ -409,7 +456,7 @@ ao_fat_root_put(uint8_t *root, dirent_t e, uint8_t write)
 /*
  * ao_fat_root_extend
  *
- * On FAT32, make the 
+ * On FAT32, make the root directory at least 'ents' entries long
  */
 static int8_t
 ao_fat_root_extend(dirent_t ents)
@@ -419,8 +466,8 @@ ao_fat_root_extend(dirent_t ents)
        if (!fat32)
                return 0;
        
-       byte_size = ents * 0x20;
-       cluster_size = byte_size / bytes_per_cluster;
+       byte_size = (ents + 1) * 0x20;
+       cluster_size = (byte_size + bytes_per_cluster - 1) / bytes_per_cluster;
        if (ao_fat_cluster_set_size(root_cluster, cluster_size) != AO_FAT_BAD_CLUSTER)
                return 1;
        return 0;
@@ -440,14 +487,14 @@ ao_fat_setup_partition(void)
 
        mbr = ao_bufio_get(0);
        if (!mbr)
-               return 0;
+               return AO_FAT_FILESYSTEM_MBR_READ_FAILURE;
 
        /* Check the signature */
        if (mbr[0x1fe] != 0x55 || mbr[0x1ff] != 0xaa) {
-               printf ("Invalid MBR signature %02x %02x\n",
+               DBG ("Invalid MBR signature %02x %02x\n",
                        mbr[0x1fe], mbr[0x1ff]);
                ao_bufio_put(mbr, 0);
-               return 0;
+               return AO_FAT_FILESYSTEM_INVALID_MBR_SIGNATURE;
        }
 
        /* Check to see if it's actually a boot block, in which
@@ -472,24 +519,22 @@ ao_fat_setup_partition(void)
                case 0x0c:      /* FAT32 LBA */
                        break;
                default:
-                       printf ("Invalid partition type %02x\n", partition_type);
+                       DBG ("Invalid partition type %02x\n", partition_type);
                        ao_bufio_put(mbr, 0);
-                       return 0;
+                       return AO_FAT_FILESYSTEM_INVALID_PARTITION_TYPE;
                }
 
                partition_start = get_u32(partition+8);
                partition_size = get_u32(partition+12);
                if (partition_size == 0) {
-                       printf ("Zero-sized partition\n");
+                       DBG ("Zero-sized partition\n");
                        ao_bufio_put(mbr, 0);
-                       return 0;
+                       return AO_FAT_FILESYSTEM_ZERO_SIZED_PARTITION;
                }
        }
        partition_end = partition_start + partition_size;
-       printf ("Partition type %02x start %08x end %08x\n",
-               partition_type, partition_start, partition_end);
        ao_bufio_put(mbr, 0);
-       return 1;
+       return AO_FAT_FILESYSTEM_SUCCESS;
 }
        
 static uint8_t
@@ -499,22 +544,22 @@ ao_fat_setup_fs(void)
        uint32_t        data_sectors;
 
        if (!boot)
-               return 0;
+               return AO_FAT_FILESYSTEM_BOOT_READ_FAILURE;
 
        /* Check the signature */
        if (boot[0x1fe] != 0x55 || boot[0x1ff] != 0xaa) {
-               printf ("Invalid BOOT signature %02x %02x\n",
+               DBG ("Invalid BOOT signature %02x %02x\n",
                        boot[0x1fe], boot[0x1ff]);
                ao_fat_sector_put(boot, 0);
-               return 0;
+               return AO_FAT_FILESYSTEM_INVALID_BOOT_SIGNATURE;
        }
 
        /* Check the sector size */
        if (get_u16(boot + 0xb) != SECTOR_SIZE) {
-               printf ("Invalid sector size %d\n",
+               DBG ("Invalid sector size %d\n",
                        get_u16(boot + 0xb));
                ao_fat_sector_put(boot, 0);
-               return 0;
+               return AO_FAT_FILESYSTEM_INVALID_SECTOR_SIZE;
        }
 
        sectors_per_cluster = boot[0xd];
@@ -552,18 +597,7 @@ ao_fat_setup_fs(void)
 
        number_cluster = data_sectors / sectors_per_cluster;
 
-       printf ("fat32: %d\n", fat32);
-       printf ("sectors per cluster %d\n", sectors_per_cluster);
-       printf ("reserved sectors %d\n", reserved_sector_count);
-       printf ("number of FATs %d\n", number_fat);
-       printf ("root entries %d\n", root_entries);
-       printf ("sectors per fat %d\n", sectors_per_fat);
-
-       printf ("fat  start %d\n", fat_start);
-       printf ("root start %d\n", root_start);
-       printf ("data start %d\n", data_start);
-
-       return 1;
+       return AO_FAT_FILESYSTEM_SUCCESS;
 }
 
 /*
@@ -574,8 +608,8 @@ static uint32_t             ao_file_offset;
 static uint32_t                        ao_file_cluster_offset;
 static cluster_t               ao_file_cluster;
 static uint8_t                 ao_file_opened;
-static uint8_t                 ao_filesystem_available;
 static uint8_t                 ao_filesystem_setup;
+static uint8_t                 ao_filesystem_status;
 
 static uint8_t
 ao_fat_setup(void)
@@ -597,13 +631,20 @@ ao_fat_setup(void)
                memset(&ao_file_dirent, '\0', sizeof (ao_file_dirent));
 
                ao_file_offset = ao_file_cluster_offset = ao_file_cluster = ao_file_opened = 0;
-               if (!ao_fat_setup_partition())
-                       return 0;
-               if (!ao_fat_setup_fs())
-                       return 0;
-               ao_filesystem_available = 1;
+               ao_filesystem_status = ao_fat_setup_partition();
+               if (ao_filesystem_status != AO_FAT_FILESYSTEM_SUCCESS)
+                       return ao_filesystem_status;
+               ao_filesystem_status = ao_fat_setup_fs();
+               if (ao_filesystem_status != AO_FAT_FILESYSTEM_SUCCESS)
+                       return ao_filesystem_status;
        }
-       return ao_filesystem_available;
+       return ao_filesystem_status;
+}
+
+void
+ao_fat_unmount(void)
+{
+       ao_filesystem_setup = 0;
 }
 
 /*
@@ -618,6 +659,9 @@ ao_fat_current_sector(void)
        uint16_t        sector_index;
        cluster_t       cluster;
 
+       DBG("current sector offset %d size %d\n",
+           ao_file_offset, ao_file_dirent.size);
+
        if (ao_file_offset > ao_file_dirent.size)
                return 0xffffffff;
 
@@ -626,6 +670,7 @@ ao_fat_current_sector(void)
        if (!ao_file_cluster || ao_file_offset < ao_file_cluster_offset) {
                ao_file_cluster = ao_file_dirent.cluster;
                ao_file_cluster_offset = 0;
+               DBG("\treset to start of file %08x\n", ao_file_cluster);
        }
 
        if (ao_file_cluster_offset + bytes_per_cluster <= ao_file_offset) {
@@ -635,6 +680,7 @@ ao_fat_current_sector(void)
 
                cluster_distance = cluster_offset - ao_file_cluster_offset / bytes_per_cluster;
 
+               DBG("\tseek forward %d clusters\n", cluster_distance);
                cluster = ao_fat_cluster_seek(ao_file_cluster, cluster_distance);
 
                if (!ao_fat_cluster_valid(cluster))
@@ -644,12 +690,16 @@ ao_fat_current_sector(void)
        }
 
        sector_index = sector_offset % sectors_per_cluster;
+       DBG("current cluster %08x sector_index %d sector %d\n",
+           ao_file_cluster, sector_index,
+           data_start + (uint32_t) (ao_file_cluster-2) * sectors_per_cluster + sector_index);
        return data_start + (uint32_t) (ao_file_cluster-2) * sectors_per_cluster + sector_index;
 }
 
 static void
 ao_fat_set_offset(uint32_t offset)
 {
+       DBG("Set offset %d\n", offset);
        ao_file_offset = offset;
 }
 
@@ -666,23 +716,30 @@ ao_fat_set_size(uint32_t size)
        cluster_t       first_cluster;
        cluster_t       have_clusters, need_clusters;
 
-       if (size == ao_file_dirent.size)
+       DBG ("Set size %d\n", size);
+       if (size == ao_file_dirent.size) {
+               DBG("\tsize match\n");
                return AO_FAT_SUCCESS;
+       }
 
        first_cluster = ao_file_dirent.cluster;
        have_clusters = (ao_file_dirent.size + bytes_per_cluster - 1) / bytes_per_cluster;
        need_clusters = (size + bytes_per_cluster - 1) / bytes_per_cluster;
 
+       DBG ("\tfirst cluster %08x have %d need %d\n", first_cluster, have_clusters, need_clusters);
        if (have_clusters != need_clusters) {
                if (ao_file_cluster && size >= ao_file_cluster_offset) {
                        cluster_t       offset_clusters = (ao_file_cluster_offset + bytes_per_cluster) / bytes_per_cluster;
                        cluster_t       extra_clusters = need_clusters - offset_clusters;
                        cluster_t       next_cluster;
 
+                       DBG ("\tset size relative offset_clusters %d extra_clusters %d\n",
+                            offset_clusters, extra_clusters);
                        next_cluster = ao_fat_cluster_set_size(ao_file_cluster, extra_clusters);
                        if (next_cluster == AO_FAT_BAD_CLUSTER)
                                return -AO_FAT_ENOSPC;
                } else {
+                       DBG ("\tset size absolute need_clusters %d\n", need_clusters);
                        first_cluster = ao_fat_cluster_set_size(first_cluster, need_clusters);
 
                        if (first_cluster == AO_FAT_BAD_CLUSTER)
@@ -690,6 +747,7 @@ ao_fat_set_size(uint32_t size)
                }
        }
 
+       DBG ("\tupdate directory size\n");
        /* Update the directory entry */
        dent = ao_fat_root_get(ao_file_dirent.entry);
        if (!dent)
@@ -702,6 +760,7 @@ ao_fat_set_size(uint32_t size)
 
        ao_file_dirent.size = size;
        ao_file_dirent.cluster = first_cluster;
+       DBG ("set size done\n");
        return AO_FAT_SUCCESS;
 }
 
@@ -796,7 +855,7 @@ ao_fat_flush_fsinfo(void)
 void
 ao_fat_sync(void)
 {
-       if (!ao_fat_setup())
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
                return;
        ao_fat_flush_fsinfo();
        ao_bufio_flush();
@@ -812,8 +871,8 @@ ao_fat_sync(void)
 int8_t
 ao_fat_full(void)
 {
-       if (!ao_fat_setup())
-               return -AO_FAT_EIO;
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
+               return 1;
        return filesystem_full;
 }
 
@@ -828,7 +887,7 @@ ao_fat_open(char name[11], uint8_t mode)
        uint16_t                entry = 0;
        struct ao_fat_dirent    dirent;
 
-       if (!ao_fat_setup())
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
                return -AO_FAT_EIO;
 
        if (ao_file_opened)
@@ -864,7 +923,7 @@ ao_fat_creat(char name[11])
        int8_t          status;
        uint8_t         *dent;
 
-       if (!ao_fat_setup())
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
                return -AO_FAT_EIO;
 
        if (ao_file_opened)
@@ -925,6 +984,32 @@ ao_fat_close(void)
        return AO_FAT_SUCCESS;
 }
 
+/*
+ * ao_fat_map_current
+ *
+ * Map the sector pointed at by the current file offset
+ */
+
+static void *
+ao_fat_map_current(int len, cluster_offset_t *offsetp, cluster_offset_t *this_time)
+{
+       cluster_offset_t        offset;
+       sector_t                sector;
+       void                    *buf;
+
+       offset = ao_file_offset & SECTOR_MASK;
+       sector = ao_fat_current_sector();
+       if (sector == 0xffffffff)
+               return NULL;
+       buf = ao_fat_sector_get(sector);
+       if (offset + len < SECTOR_SIZE)
+               *this_time = len;
+       else
+               *this_time = SECTOR_SIZE - offset;
+       *offsetp = offset;
+       return buf;
+}
+
 /*
  * ao_fat_read
  *
@@ -933,12 +1018,11 @@ ao_fat_close(void)
 int
 ao_fat_read(void *dst, int len)
 {
-       uint8_t         *dst_b = dst;
-       uint32_t        sector;
-       uint16_t        this_time;
-       uint16_t        offset;
-       uint8_t         *buf;
-       int             ret = 0;
+       uint8_t                 *dst_b = dst;
+       cluster_offset_t        this_time;
+       cluster_offset_t        offset;
+       uint8_t                 *buf;
+       int                     ret = 0;
 
        if (!ao_file_opened)
                return -AO_FAT_EBADF;
@@ -950,16 +1034,7 @@ ao_fat_read(void *dst, int len)
                len = 0;
 
        while (len) {
-               offset = ao_file_offset & SECTOR_MASK;
-               if (offset + len < SECTOR_SIZE)
-                       this_time = len;
-               else
-                       this_time = SECTOR_SIZE - offset;
-
-               sector = ao_fat_current_sector();
-               if (sector == 0xffffffff)
-                       break;
-               buf = ao_fat_sector_get(sector);
+               buf = ao_fat_map_current(len, &offset, &this_time);
                if (!buf) {
                        ret = -AO_FAT_EIO;
                        break;
@@ -984,7 +1059,6 @@ int
 ao_fat_write(void *src, int len)
 {
        uint8_t         *src_b = src;
-       uint32_t        sector;
        uint16_t        this_time;
        uint16_t        offset;
        uint8_t         *buf;
@@ -1000,16 +1074,7 @@ ao_fat_write(void *src, int len)
        }
 
        while (len) {
-               offset = ao_file_offset & SECTOR_MASK;
-               if (offset + len < SECTOR_SIZE)
-                       this_time = len;
-               else
-                       this_time = SECTOR_SIZE - offset;
-
-               sector = ao_fat_current_sector();
-               if (sector == 0xffffffff)
-                       break;
-               buf = ao_fat_sector_get(sector);
+               buf = ao_fat_map_current(len, &offset, &this_time);
                if (!buf) {
                        ret = -AO_FAT_EIO;
                        break;
@@ -1069,8 +1134,9 @@ ao_fat_unlink(char name[11])
        uint16_t                entry = 0;
        struct ao_fat_dirent    dirent;
 
-       if (!ao_fat_setup())
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
                return -AO_FAT_EIO;
+
        while (ao_fat_readdir(&entry, &dirent)) {
                if (memcmp(name, dirent.name, 11) == 0) {
                        uint8_t *next;
@@ -1114,49 +1180,205 @@ ao_fat_readdir(uint16_t *entry, struct ao_fat_dirent *dirent)
 {
        uint8_t *dent;
 
-       if (!ao_fat_setup())
+       if (ao_fat_setup() != AO_FAT_FILESYSTEM_SUCCESS)
                return -AO_FAT_EIO;
+
        for (;;) {
                dent = ao_fat_root_get(*entry);
                if (!dent)
-                       return 0;
+                       return -AO_FAT_EDIREOF;
 
                if (dent[0] == AO_FAT_DENT_END) {
                        ao_fat_root_put(dent, *entry, 0);
-                       return 0;
+                       return -AO_FAT_EDIREOF;
                }
                if (dent[0] != AO_FAT_DENT_EMPTY && (dent[0xb] & 0xf) != 0xf) {
                        ao_fat_dirent_init(dent, *entry, dirent);
                        ao_fat_root_put(dent, *entry, 0);
                        (*entry)++;
-                       return 1;
+                       return AO_FAT_SUCCESS;
                }
                ao_fat_root_put(dent, *entry, 0);
                (*entry)++;
        }
 }
 
+#if FAT_COMMANDS
+
+static const char *filesystem_errors[] = {
+       [AO_FAT_FILESYSTEM_SUCCESS] = "FAT file system operating normally",
+       [AO_FAT_FILESYSTEM_MBR_READ_FAILURE] = "MBR media read error",
+       [AO_FAT_FILESYSTEM_INVALID_MBR_SIGNATURE] = "MBR signature invalid",
+       [AO_FAT_FILESYSTEM_INVALID_PARTITION_TYPE] = "Unsupported paritition type",
+       [AO_FAT_FILESYSTEM_ZERO_SIZED_PARTITION] = "Partition has zero sectors",
+       [AO_FAT_FILESYSTEM_BOOT_READ_FAILURE] = "Boot block media read error",
+       [AO_FAT_FILESYSTEM_INVALID_BOOT_SIGNATURE] = "Boot block signature invalid",
+       [AO_FAT_FILESYSTEM_INVALID_SECTOR_SIZE] = "Sector size not 512",
+};
+       
 static void
-ao_fat_list(void)
+ao_fat_mbr_cmd(void)
+{
+       uint8_t status;
+
+       status = ao_fat_setup();
+       if (status == AO_FAT_FILESYSTEM_SUCCESS) {
+               printf ("partition type: %02x\n", partition_type);
+               printf ("partition start: %08x\n", partition_start);
+
+               printf ("partition end:   %08x\n", partition_end);
+
+               printf ("fat32: %d\n", fat32);
+               printf ("sectors per cluster %d\n", sectors_per_cluster);
+               printf ("reserved sectors %d\n", reserved_sector_count);
+               printf ("number of FATs %d\n", number_fat);
+               printf ("root entries %d\n", root_entries);
+               printf ("sectors per fat %d\n", sectors_per_fat);
+
+               printf ("fat  start %d\n", fat_start);
+               printf ("root start %d\n", root_start);
+               printf ("data start %d\n", data_start);
+       } else {
+               printf ("FAT filesystem not available: %s\n", filesystem_errors[status]);
+       }
+}
+
+struct ao_fat_attr {
+       uint8_t bit;
+       char    label;
+};
+
+static const struct ao_fat_attr ao_fat_attr[] = {
+       { .bit = AO_FAT_FILE_READ_ONLY, .label = 'R' },
+       { .bit = AO_FAT_FILE_HIDDEN, .label = 'H' },
+       { .bit = AO_FAT_FILE_SYSTEM, .label = 'S' },
+       { .bit = AO_FAT_FILE_VOLUME_LABEL, .label = 'V' },
+       { .bit = AO_FAT_FILE_DIRECTORY, .label = 'D' },
+       { .bit = AO_FAT_FILE_ARCHIVE, .label = 'A' },
+};
+
+#define NUM_FAT_ATTR   (sizeof (ao_fat_attr) / sizeof (ao_fat_attr[0]))
+
+static void
+ao_fat_list_cmd(void)
 {
        uint16_t                entry = 0;
        struct ao_fat_dirent    dirent;
+       int                     i;
+       int8_t                  status;
+
+       while ((status = ao_fat_readdir(&entry, &dirent)) == AO_FAT_SUCCESS) {
+               for (i = 0; i < 8; i++)
+                       putchar(dirent.name[i]);
+               putchar('.');
+               for (; i < 11; i++)
+                       putchar(dirent.name[i]);
+               for (i = 0; i < NUM_FAT_ATTR; i++)
+                       putchar (dirent.attr & ao_fat_attr[i].bit ? ao_fat_attr[i].label : ' ');
+               printf (" @%08x %d\n", dirent.cluster, dirent.size);
+       }
+       if (status != -AO_FAT_EDIREOF)
+               printf ("readdir failed: %d\n", status);
+}
 
-       while (ao_fat_readdir(&entry, &dirent)) {
-               printf ("%-8.8s.%-3.3s %02x %04x %d\n",
-                       dirent.name,
-                       dirent.name + 8,
-                       dirent.attr,
-                       dirent.cluster,
-                       dirent.size);
+static uint8_t
+ao_fat_parse_name(char name[11])
+{
+       uint8_t c;
+
+       name[0] = '\0';
+       ao_cmd_white();
+       c = 0;
+       while (ao_cmd_lex_c != '\n') {
+               if (ao_cmd_lex_c == '.') {
+                       for (; c < 8; c++)
+                               name[c] = ' ';
+               } else {
+                       if (c < 11)
+                               name[c++] = ao_cmd_lex_c;
+               }
+               ao_cmd_lex();
+       }
+       while (c < 11)
+               name[c++] = ' ';
+}
+
+static void
+ao_fat_show_cmd(void)
+{
+       char            name[11];
+       int8_t          status;
+       int             cnt, i;
+       char            buf[64];
+
+       ao_fat_parse_name(name);
+       if (name[0] == '\0') {
+               ao_cmd_status = ao_cmd_syntax_error;
+               return;
+       }
+               
+       status = ao_fat_open(name, AO_FAT_OPEN_READ);
+       if (status) {
+               printf ("Open failed: %d\n", status);
+               return;
+       }
+       while ((cnt = ao_fat_read(buf, sizeof(buf))) > 0) {
+               for (i = 0; i < cnt; i++)
+                       putchar(buf[i]);
        }
+       ao_fat_close();
+}
+
+static void
+ao_fat_putchar(char c)
+{
+}
+
+static void
+ao_fat_write_cmd(void)
+{
+       char            name[11];
+       int8_t          status;
+       int             cnt, i;
+       char            buf[64];
+       char            c;
+
+       ao_fat_parse_name(name);
+       if (name[0] == '\0') {
+               ao_cmd_status = ao_cmd_syntax_error;
+               return;
+       }
+               
+       status = ao_fat_creat(name);
+       if (status) {
+               printf ("Open failed: %d\n", status);
+               return;
+       }
+       flush();
+       while ((c = getchar()) != 4) {
+               if (c == '\r') c = '\n';
+               if (ao_echo()) {
+                       if (c == '\n') putchar ('\r');
+                       putchar(c); flush();
+               }
+               if (ao_fat_write(&c, 1) != 1) {
+                       printf ("Write failure\n");
+                       break;
+               }
+       }
+       ao_fat_close();
 }
 
 static const struct ao_cmds ao_fat_cmds[] = {
-       { ao_fat_list,  "F\0List FAT" },
+       { ao_fat_mbr_cmd,       "M\0Show FAT MBR and other info" },
+       { ao_fat_list_cmd,      "F\0List FAT directory" },
+       { ao_fat_show_cmd,      "S <name>\0Show FAT file" },
+       { ao_fat_write_cmd,     "W <name>\0Write FAT file (end with ^D)" },
        { 0, NULL },
 };
 
+#endif
+
 void
 ao_fat_init(void)
 {