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  1. /*
  2.  * Copyright (c) 2008 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup fs
  30.  * @{
  31.  */
  32.  
  33. #ifndef FAT_FAT_H_
  34. #define FAT_FAT_H_
  35.  
  36. #include "fat_fat.h"
  37. #include <ipc/ipc.h>
  38. #include <fibril_sync.h>
  39. #include <libfs.h>
  40. #include <atomic.h>
  41. #include <sys/types.h>
  42. #include <bool.h>
  43. #include "../../vfs/vfs.h"
  44.  
  45. #ifndef dprintf
  46. #define dprintf(...)    printf(__VA_ARGS__)
  47. #endif
  48.  
  49. #define min(a, b)       ((a) < (b) ? (a) : (b))
  50.  
  51. #define BS_BLOCK        0
  52. #define BS_SIZE         512
  53.  
  54. typedef struct fat_bs {
  55.     uint8_t     ji[3];      /**< Jump instruction. */
  56.     uint8_t     oem_name[8];
  57.     /* BIOS Parameter Block */
  58.     uint16_t    bps;        /**< Bytes per sector. */
  59.     uint8_t     spc;        /**< Sectors per cluster. */
  60.     uint16_t    rscnt;      /**< Reserved sector count. */
  61.     uint8_t     fatcnt;     /**< Number of FATs. */
  62.     uint16_t    root_ent_max;   /**< Maximum number of root directory
  63.                          entries. */
  64.     uint16_t    totsec16;   /**< Total sectors. 16-bit version. */
  65.     uint8_t     mdesc;      /**< Media descriptor. */
  66.     uint16_t    sec_per_fat;    /**< Sectors per FAT12/FAT16. */
  67.     uint16_t    sec_per_track;  /**< Sectors per track. */
  68.     uint16_t    headcnt;    /**< Number of heads. */
  69.     uint32_t    hidden_sec; /**< Hidden sectors. */
  70.     uint32_t    totsec32;   /**< Total sectors. 32-bit version. */
  71.  
  72.     union {
  73.         struct {
  74.             /* FAT12/FAT16 only: Extended BIOS Parameter Block */
  75.             /** Physical drive number. */
  76.             uint8_t     pdn;
  77.             uint8_t     reserved;
  78.             /** Extended boot signature. */
  79.             uint8_t     ebs;
  80.             /** Serial number. */
  81.             uint32_t    id;
  82.             /** Volume label. */
  83.             uint8_t     label[11];
  84.             /** FAT type. */
  85.             uint8_t     type[8];
  86.             /** Boot code. */
  87.             uint8_t     boot_code[448];
  88.             /** Boot sector signature. */
  89.             uint16_t    signature;
  90.         } __attribute__ ((packed));
  91.         struct {
  92.             /* FAT32 only */
  93.             /** Sectors per FAT. */
  94.             uint32_t    sectors_per_fat;
  95.             /** FAT flags. */
  96.             uint16_t    flags;
  97.             /** Version. */
  98.             uint16_t    version;
  99.             /** Cluster number of root directory. */
  100.             uint32_t    root_cluster;
  101.             /** Sector number of file system information sector. */
  102.             uint16_t    fsinfo_sec;
  103.             /** Sector number of boot sector copy. */
  104.             uint16_t    bscopy_sec;
  105.             uint8_t     reserved1[12];
  106.             /** Physical drive number. */
  107.             uint8_t     pdn;
  108.             uint8_t     reserved2;
  109.             /** Extended boot signature. */
  110.             uint8_t     ebs;
  111.             /** Serial number. */
  112.             uint32_t    id;
  113.             /** Volume label. */
  114.             uint8_t     label[11];
  115.             /** FAT type. */
  116.             uint8_t     type[8];
  117.             /** Boot code. */
  118.             uint8_t     boot_code[420];
  119.             /** Signature. */
  120.             uint16_t    signature;
  121.         } __attribute__ ((packed));
  122.     };
  123. } __attribute__ ((packed)) fat_bs_t;
  124.  
  125. typedef enum {
  126.     FAT_INVALID,
  127.     FAT_DIRECTORY,
  128.     FAT_FILE
  129. } fat_node_type_t;
  130.  
  131. struct fat_node;
  132.  
  133. /** FAT index structure.
  134.  *
  135.  * This structure exists to help us to overcome certain limitations of the FAT
  136.  * file system design.  The problem with FAT is that it is hard to find
  137.  * an entity which could represent a VFS index.  There are two candidates:
  138.  *
  139.  * a) number of the node's first cluster
  140.  * b) the pair of the parent directory's first cluster and the dentry index
  141.  *    within the parent directory
  142.  *
  143.  * We need VFS indices to be:
  144.  * A) unique
  145.  * B) stable in time, at least until the next mount
  146.  *
  147.  * Unfortunately a) does not meet the A) criterion because zero-length files
  148.  * will have the first cluster field cleared.  And b) does not meet the B)
  149.  * criterion because unlink() and rename() will both free up the original
  150.  * dentry, which contains all the essential info about the file.
  151.  *
  152.  * Therefore, a completely opaque indices are used and the FAT server maintains
  153.  * a mapping between them and otherwise nice b) variant.  On rename(), the VFS
  154.  * index stays unaltered, while the internal FAT "physical tree address"
  155.  * changes.  The unlink case is also handled this way thanks to an in-core node
  156.  * pointer embedded in the index structure.
  157.  */
  158. typedef struct {
  159.     /** Used indices (position) hash table link. */
  160.     link_t      uph_link;
  161.     /** Used indices (index) hash table link. */
  162.     link_t      uih_link;
  163.  
  164.     fibril_mutex_t  lock;
  165.     dev_handle_t    dev_handle;
  166.     fs_index_t  index;
  167.     /**
  168.      * Parent node's first cluster.
  169.      * Zero is used if this node is not linked, in which case nodep must
  170.      * contain a pointer to the in-core node structure.
  171.      * One is used when the parent is the root directory.
  172.      */
  173.     fat_cluster_t   pfc;
  174.     /** Directory entry index within the parent node. */
  175.     unsigned    pdi;
  176.     /** Pointer to in-core node instance. */
  177.     struct fat_node *nodep;
  178. } fat_idx_t;
  179.  
  180. /** FAT in-core node. */
  181. typedef struct fat_node {
  182.     /** Back pointer to the FS node. */
  183.     fs_node_t       *bp;
  184.    
  185.     fibril_mutex_t      lock;
  186.     fat_node_type_t     type;
  187.     fat_idx_t       *idx;
  188.     /**
  189.      *  Node's first cluster.
  190.      *  Zero is used for zero-length nodes.
  191.      *  One is used to mark root directory.
  192.      */
  193.     fat_cluster_t       firstc;
  194.     /** FAT in-core node free list link. */
  195.     link_t          ffn_link;
  196.     size_t          size;
  197.     unsigned        lnkcnt;
  198.     unsigned        refcnt;
  199.     bool            dirty;
  200. } fat_node_t;
  201.  
  202. extern fs_reg_t fat_reg;
  203.  
  204. extern void fat_mounted(ipc_callid_t, ipc_call_t *);
  205. extern void fat_mount(ipc_callid_t, ipc_call_t *);
  206. extern void fat_lookup(ipc_callid_t, ipc_call_t *);
  207. extern void fat_read(ipc_callid_t, ipc_call_t *);
  208. extern void fat_write(ipc_callid_t, ipc_call_t *);
  209. extern void fat_truncate(ipc_callid_t, ipc_call_t *);
  210. extern void fat_stat(ipc_callid_t, ipc_call_t *);
  211. extern void fat_close(ipc_callid_t, ipc_call_t *);
  212. extern void fat_destroy(ipc_callid_t, ipc_call_t *);
  213. extern void fat_open_node(ipc_callid_t, ipc_call_t *);
  214. extern void fat_stat(ipc_callid_t, ipc_call_t *);
  215. extern void fat_sync(ipc_callid_t, ipc_call_t *);
  216.  
  217. extern fat_idx_t *fat_idx_get_new(dev_handle_t);
  218. extern fat_idx_t *fat_idx_get_by_pos(dev_handle_t, fat_cluster_t, unsigned);
  219. extern fat_idx_t *fat_idx_get_by_index(dev_handle_t, fs_index_t);
  220. extern void fat_idx_destroy(fat_idx_t *);
  221. extern void fat_idx_hashin(fat_idx_t *);
  222. extern void fat_idx_hashout(fat_idx_t *);
  223.  
  224. extern int fat_idx_init(void);
  225. extern void fat_idx_fini(void);
  226. extern int fat_idx_init_by_dev_handle(dev_handle_t);
  227. extern void fat_idx_fini_by_dev_handle(dev_handle_t);
  228.  
  229. #endif
  230.  
  231. /**
  232.  * @}
  233.  */
  234.