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  1. /*
  2.  * Copyright (c) 2007 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 <sys/types.h>
  40.  
  41. #define dprintf(...)    printf(__VA_ARGS__)
  42.  
  43. #define VFS_FIRST   FIRST_USER_METHOD
  44.  
  45. #define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)  
  46.  
  47. typedef enum {
  48.     VFS_REGISTER = VFS_FIRST,
  49.     VFS_MOUNT,
  50.     VFS_UNMOUNT,
  51.     VFS_LOOKUP,
  52.     VFS_OPEN,
  53.     VFS_CREATE,
  54.     VFS_CLOSE,
  55.     VFS_READ,
  56.     VFS_WRITE,
  57.     VFS_SEEK,
  58.     VFS_LAST,       /* keep this the last member of the enum */
  59. } vfs_request_t;
  60.  
  61.  
  62. /**
  63.  * An instance of this structure is associated with a particular FS operation.
  64.  * It tells VFS if the FS supports the operation or maybe if a default one
  65.  * should be used.
  66.  */
  67. typedef enum {
  68.     VFS_OP_NULL = 0,
  69.     VFS_OP_DEFAULT,
  70.     VFS_OP_DEFINED
  71. } vfs_op_t;
  72.  
  73. #define FS_NAME_MAXLEN  20
  74.  
  75. /**
  76.  * A structure like this is passed to VFS by each individual FS upon its
  77.  * registration. It assosiates a human-readable identifier with each
  78.  * registered FS. More importantly, through this structure, the FS announces
  79.  * what operations it supports.
  80.  */
  81. typedef struct {
  82.     /** Unique identifier of the fs. */
  83.     char name[FS_NAME_MAXLEN];
  84.    
  85.     /** Operations. */
  86.     vfs_op_t ops[VFS_LAST - VFS_FIRST];
  87. } vfs_info_t;
  88.  
  89. /**
  90.  * A structure like this will be allocated for each registered file system.
  91.  */
  92. typedef struct {
  93.     link_t fs_link;
  94.     vfs_info_t vfs_info;
  95.     int fs_handle;
  96.     atomic_t phone_futex;   /**< Phone serializing futex. */
  97.     ipcarg_t phone;
  98. } fs_info_t;
  99.  
  100. /**
  101.  * Instances of this type represent a file system node (e.g. directory, file).
  102.  * They are abstracted away from any file system implementation and contain just
  103.  * enough bits to uniquely identify the object in its file system instance.
  104.  *
  105.  * @note    fs_handle, dev_handle and index are meant to be returned in one
  106.  *      IPC reply.
  107.  */
  108. typedef struct {
  109.     int fs_handle;      /**< Global file system ID. */
  110.     int dev_handle;     /**< Global mount device devno. */
  111.     uint64_t index;     /**< Index of the node on its file system. */
  112. } vfs_node_t;
  113.  
  114. /**
  115.  * Instances of this type represent an open file. If the file is opened by more
  116.  * than one task, there will be a separate structure allocated for each task.
  117.  */
  118. typedef struct {
  119.     vfs_node_t *node;
  120.    
  121.     /** Number of file handles referencing this file. */
  122.     atomic_t refcnt;
  123.  
  124.     /** Current position in the file. */
  125.     off_t pos;
  126. } vfs_file_t;
  127.  
  128. extern link_t fs_head;      /**< List of registered file systems. */
  129.  
  130. extern vfs_node_t *rootfs;  /**< Root node of the root file system. */
  131.  
  132. #define MAX_PATH_LEN        (64 * 1024)
  133.  
  134. #define PLB_SIZE        (2 * MAX_PATH_LEN)
  135.  
  136. /** Each instance of this type describes one path lookup in progress. */
  137. typedef struct {
  138.     link_t  plb_link;   /**< Active PLB entries list link. */
  139.     unsigned index;     /**< Index of the first character in PLB. */
  140.     size_t len;     /**< Number of characters in this PLB entry. */
  141. } plb_entry_t;
  142.  
  143. extern atomic_t plb_futex;  /**< Futex protecting plb and plb_head. */
  144. extern uint8_t *plb;        /**< Path Lookup Buffer */
  145. extern link_t plb_head;     /**< List of active PLB entries. */
  146.  
  147. extern int vfs_grab_phone(int);
  148. extern void vfs_release_phone(int);
  149.  
  150. extern int vfs_lookup_internal(char *path, size_t len, vfs_node_t *result);
  151.  
  152. extern void vfs_register(ipc_callid_t, ipc_call_t *);
  153. extern void vfs_mount(ipc_callid_t, ipc_call_t *);
  154.  
  155. #endif
  156.  
  157. /**
  158.  * @}
  159.  */
  160.