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