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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 VFS_VFS_H_
  34. #define VFS_VFS_H_
  35.  
  36. #include <ipc/ipc.h>
  37. #include <libadt/list.h>
  38. #include <atomic.h>
  39. #include <rwlock.h>
  40. #include <sys/types.h>
  41. #include <bool.h>
  42.  
  43. #define dprintf(...)    printf(__VA_ARGS__)
  44.  
  45. #define VFS_FIRST   IPC_FIRST_USER_METHOD
  46.  
  47. #define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)  
  48.  
  49. typedef enum {
  50.     VFS_REGISTER = VFS_FIRST,
  51.     VFS_MOUNT,
  52.     VFS_UNMOUNT,
  53.     VFS_LOOKUP,
  54.     VFS_OPEN,
  55.     VFS_CREATE,
  56.     VFS_CLOSE,
  57.     VFS_READ,
  58.     VFS_WRITE,
  59.     VFS_SEEK,
  60.     VFS_RENAME,
  61.     VFS_UNLINK,
  62.     VFS_LAST,       /* keep this the last member of the enum */
  63. } vfs_request_t;
  64.  
  65.  
  66. /**
  67.  * An instance of this structure is associated with a particular FS operation.
  68.  * It tells VFS if the FS supports the operation or maybe if a default one
  69.  * should be used.
  70.  */
  71. typedef enum {
  72.     VFS_OP_NULL = 0,
  73.     VFS_OP_DEFAULT,
  74.     VFS_OP_DEFINED
  75. } vfs_op_t;
  76.  
  77. #define FS_NAME_MAXLEN  20
  78.  
  79. /**
  80.  * A structure like this is passed to VFS by each individual FS upon its
  81.  * registration. It assosiates a human-readable identifier with each
  82.  * registered FS. More importantly, through this structure, the FS announces
  83.  * what operations it supports.
  84.  */
  85. typedef struct {
  86.     /** Unique identifier of the fs. */
  87.     char name[FS_NAME_MAXLEN + 1];
  88.    
  89.     /** Operations. */
  90.     vfs_op_t ops[VFS_LAST - VFS_FIRST];
  91. } vfs_info_t;
  92.  
  93. /**
  94.  * A structure like this will be allocated for each registered file system.
  95.  */
  96. typedef struct {
  97.     link_t fs_link;
  98.     vfs_info_t vfs_info;
  99.     int fs_handle;
  100.     atomic_t phone_futex;   /**< Phone serializing futex. */
  101.     ipcarg_t phone;
  102. } fs_info_t;
  103.  
  104. /**
  105.  * VFS_PAIR uniquely represents a file system instance.
  106.  */
  107. #define VFS_PAIR    \
  108.     int fs_handle;  \
  109.     int dev_handle;
  110.  
  111. /**
  112.  * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
  113.  * doesn't contain any state. For a stateful structure, see vfs_node_t.
  114.  *
  115.  * @note    fs_handle, dev_handle and index are meant to be returned in one
  116.  *      IPC reply.
  117.  */
  118. #define VFS_TRIPLET \
  119.     VFS_PAIR;   \
  120.     uint64_t index;
  121.  
  122. typedef struct {
  123.     VFS_PAIR;
  124. } vfs_pair_t;
  125.  
  126. typedef struct {
  127.     VFS_TRIPLET;
  128. } vfs_triplet_t;
  129.  
  130. /**
  131.  * Instances of this type represent an active, in-memory VFS node and any state
  132.  * which may be associated with it.
  133.  */
  134. typedef struct {
  135.     VFS_TRIPLET;        /**< Identity of the node. */
  136.     unsigned refcnt;    /**< Usage counter. */
  137.     link_t nh_link;     /**< Node hash-table link. */
  138.     size_t size;        /**< Cached size of the file. */
  139.  
  140.     /**
  141.      * Holding this rwlock prevents modifications of the node's contents.
  142.      */
  143.     rwlock_t contents_rwlock;
  144. } vfs_node_t;
  145.  
  146. /**
  147.  * Instances of this type represent an open file. If the file is opened by more
  148.  * than one task, there will be a separate structure allocated for each task.
  149.  */
  150. typedef struct {
  151.     /** Serializes access to this open file. */
  152.     futex_t lock;
  153.  
  154.     vfs_node_t *node;
  155.    
  156.     /** Number of file handles referencing this file. */
  157.     unsigned refcnt;
  158.  
  159.     /** Current position in the file. */
  160.     off_t pos;
  161. } vfs_file_t;
  162.  
  163. extern link_t fs_head;      /**< List of registered file systems. */
  164.  
  165. extern vfs_triplet_t rootfs;    /**< Root node of the root file system. */
  166.  
  167. #define MAX_PATH_LEN        (64 * 1024)
  168.  
  169. #define PLB_SIZE        (2 * MAX_PATH_LEN)
  170.  
  171. /** Each instance of this type describes one path lookup in progress. */
  172. typedef struct {
  173.     link_t  plb_link;   /**< Active PLB entries list link. */
  174.     unsigned index;     /**< Index of the first character in PLB. */
  175.     size_t len;     /**< Number of characters in this PLB entry. */
  176. } plb_entry_t;
  177.  
  178. extern atomic_t plb_futex;  /**< Futex protecting plb and plb_head. */
  179. extern uint8_t *plb;        /**< Path Lookup Buffer */
  180. extern link_t plb_head;     /**< List of active PLB entries. */
  181.  
  182. /** Holding this rwlock prevents changes in file system namespace. */
  183. extern rwlock_t namespace_rwlock;
  184.  
  185. extern int vfs_grab_phone(int);
  186. extern void vfs_release_phone(int);
  187.  
  188. extern int fs_name_to_handle(char *, bool);
  189.  
  190. extern int vfs_lookup_internal(char *, size_t, vfs_triplet_t *, vfs_pair_t *);
  191.  
  192. extern bool vfs_nodes_init(void);
  193. extern vfs_node_t *vfs_node_get(vfs_triplet_t *);
  194. extern void vfs_node_put(vfs_node_t *);
  195.  
  196. #define MAX_OPEN_FILES  128
  197.  
  198. extern bool vfs_files_init(void);
  199. extern vfs_file_t *vfs_file_get(int);
  200. extern int vfs_fd_alloc(void);
  201. extern void vfs_fd_free(int);
  202.  
  203. extern void vfs_file_addref(vfs_file_t *);
  204. extern void vfs_file_delref(vfs_file_t *);
  205.  
  206. extern void vfs_node_addref(vfs_node_t *);
  207. extern void vfs_node_delref(vfs_node_t *);
  208.  
  209. extern void vfs_register(ipc_callid_t, ipc_call_t *);
  210. extern void vfs_mount(ipc_callid_t, ipc_call_t *);
  211. extern void vfs_open(ipc_callid_t, ipc_call_t *);
  212. extern void vfs_read(ipc_callid_t, ipc_call_t *);
  213. extern void vfs_write(ipc_callid_t, ipc_call_t *);
  214. extern void vfs_seek(ipc_callid_t, ipc_call_t *);
  215.  
  216. #endif
  217.  
  218. /**
  219.  * @}
  220.  */
  221.