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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_OPEN = VFS_FIRST,
  51.     VFS_CLOSE,
  52.     VFS_READ,
  53.     VFS_WRITE,
  54.     VFS_TRUNCATE,
  55.     VFS_RENAME,
  56.     VFS_OPENDIR,
  57.     VFS_READDIR,
  58.     VFS_CLOSEDIR,
  59.     VFS_UNLINK,
  60.     VFS_MOUNT,
  61.     VFS_UNMOUNT,
  62.     VFS_LAST_CMN,   /* keep this the last member of this enum */
  63. } vfs_request_cmn_t;
  64.  
  65. typedef enum {
  66.     VFS_LOOKUP = VFS_LAST_CMN,
  67.     VFS_LAST_CLNT,  /* keep this the last member of this enum */
  68. } vfs_request_clnt_t;
  69.  
  70. typedef enum {
  71.     VFS_REGISTER = VFS_LAST_CMN,
  72.     VFS_SEEK,
  73.     VFS_LAST_SRV,   /* keep this the last member of this enum */
  74. } vfs_request_srv_t;
  75.  
  76.  
  77. /**
  78.  * An instance of this structure is associated with a particular FS operation.
  79.  * It tells VFS if the FS supports the operation or maybe if a default one
  80.  * should be used.
  81.  */
  82. typedef enum {
  83.     VFS_OP_NULL = 0,
  84.     VFS_OP_DEFAULT,
  85.     VFS_OP_DEFINED
  86. } vfs_op_t;
  87.  
  88. #define FS_NAME_MAXLEN  20
  89.  
  90. /**
  91.  * A structure like this is passed to VFS by each individual FS upon its
  92.  * registration. It assosiates a human-readable identifier with each
  93.  * registered FS. More importantly, through this structure, the FS announces
  94.  * what operations it supports.
  95.  */
  96. typedef struct {
  97.     /** Unique identifier of the fs. */
  98.     char name[FS_NAME_MAXLEN + 1];
  99.    
  100.     /** Operations. */
  101.     vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
  102. } vfs_info_t;
  103.  
  104. /**
  105.  * A structure like this will be allocated for each registered file system.
  106.  */
  107. typedef struct {
  108.     link_t fs_link;
  109.     vfs_info_t vfs_info;
  110.     int fs_handle;
  111.     atomic_t phone_futex;   /**< Phone serializing futex. */
  112.     ipcarg_t phone;
  113. } fs_info_t;
  114.  
  115. /**
  116.  * VFS_PAIR uniquely represents a file system instance.
  117.  */
  118. #define VFS_PAIR    \
  119.     int fs_handle;  \
  120.     int dev_handle;
  121.  
  122. /**
  123.  * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
  124.  * doesn't contain any state. For a stateful structure, see vfs_node_t.
  125.  *
  126.  * @note    fs_handle, dev_handle and index are meant to be returned in one
  127.  *      IPC reply.
  128.  */
  129. #define VFS_TRIPLET \
  130.     VFS_PAIR;   \
  131.     uint64_t index;
  132.  
  133. typedef struct {
  134.     VFS_PAIR;
  135. } vfs_pair_t;
  136.  
  137. typedef struct {
  138.     VFS_TRIPLET;
  139. } vfs_triplet_t;
  140.  
  141. /*
  142.  * Lookup flags.
  143.  */
  144. /**
  145.  * Lookup will succeed only if the object is a regular file.  If L_CREATE is
  146.  * specified, an empty file will be created. This flag is mutually exclusive
  147.  * with L_DIRECTORY.
  148.  */
  149. #define L_FILE      1
  150. /**
  151.  * Lookup wil succeed only if the object is a directory. If L_CREATE is
  152.  * specified, an empty directory will be created. This flag is mutually
  153.  * exclusive with L_FILE.
  154.  */
  155. #define L_DIRECTORY 2
  156. /**
  157.  * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
  158.  * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
  159.  */
  160. #define L_EXCLUSIVE 4
  161. /**
  162.  * L_CREATE is used for creating both regular files and directories.
  163.  */
  164. #define L_CREATE    8
  165. /**
  166.  * L_DESTROY is used to remove leaves from the file system namespace. This flag
  167.  * cannot be passed directly by the client, but will be set by VFS during
  168.  * VFS_UNLINK.
  169.  */
  170. #define L_DESTROY   16
  171.  
  172. typedef struct {
  173.     vfs_triplet_t triplet;
  174.     size_t size;
  175. } vfs_lookup_res_t;
  176.  
  177. /**
  178.  * Instances of this type represent an active, in-memory VFS node and any state
  179.  * which may be associated with it.
  180.  */
  181. typedef struct {
  182.     VFS_TRIPLET;        /**< Identity of the node. */
  183.     unsigned refcnt;    /**< Usage counter. */
  184.     link_t nh_link;     /**< Node hash-table link. */
  185.     size_t size;        /**< Cached size of the file. */
  186.  
  187.     /**
  188.      * Holding this rwlock prevents modifications of the node's contents.
  189.      */
  190.     rwlock_t contents_rwlock;
  191. } vfs_node_t;
  192.  
  193. /**
  194.  * Instances of this type represent an open file. If the file is opened by more
  195.  * than one task, there will be a separate structure allocated for each task.
  196.  */
  197. typedef struct {
  198.     /** Serializes access to this open file. */
  199.     futex_t lock;
  200.  
  201.     vfs_node_t *node;
  202.    
  203.     /** Number of file handles referencing this file. */
  204.     unsigned refcnt;
  205.  
  206.     /** Current position in the file. */
  207.     off_t pos;
  208. } vfs_file_t;
  209.  
  210. extern link_t fs_head;      /**< List of registered file systems. */
  211.  
  212. extern vfs_triplet_t rootfs;    /**< Root node of the root file system. */
  213.  
  214. #define MAX_PATH_LEN        (64 * 1024)
  215.  
  216. #define PLB_SIZE        (2 * MAX_PATH_LEN)
  217.  
  218. /** Each instance of this type describes one path lookup in progress. */
  219. typedef struct {
  220.     link_t  plb_link;   /**< Active PLB entries list link. */
  221.     unsigned index;     /**< Index of the first character in PLB. */
  222.     size_t len;     /**< Number of characters in this PLB entry. */
  223. } plb_entry_t;
  224.  
  225. extern atomic_t plb_futex;  /**< Futex protecting plb and plb_head. */
  226. extern uint8_t *plb;        /**< Path Lookup Buffer */
  227. extern link_t plb_head;     /**< List of active PLB entries. */
  228.  
  229. /** Holding this rwlock prevents changes in file system namespace. */
  230. extern rwlock_t namespace_rwlock;
  231.  
  232. extern int vfs_grab_phone(int);
  233. extern void vfs_release_phone(int);
  234.  
  235. extern int fs_name_to_handle(char *, bool);
  236.  
  237. extern int vfs_lookup_internal(char *, size_t, int, vfs_lookup_res_t *,
  238.     vfs_pair_t *);
  239.  
  240. extern bool vfs_nodes_init(void);
  241. extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
  242. extern void vfs_node_put(vfs_node_t *);
  243.  
  244. #define MAX_OPEN_FILES  128
  245.  
  246. extern bool vfs_files_init(void);
  247. extern vfs_file_t *vfs_file_get(int);
  248. extern int vfs_fd_alloc(void);
  249. extern void vfs_fd_free(int);
  250.  
  251. extern void vfs_file_addref(vfs_file_t *);
  252. extern void vfs_file_delref(vfs_file_t *);
  253.  
  254. extern void vfs_node_addref(vfs_node_t *);
  255. extern void vfs_node_delref(vfs_node_t *);
  256.  
  257. extern void vfs_register(ipc_callid_t, ipc_call_t *);
  258. extern void vfs_mount(ipc_callid_t, ipc_call_t *);
  259. extern void vfs_open(ipc_callid_t, ipc_call_t *);
  260. extern void vfs_read(ipc_callid_t, ipc_call_t *);
  261. extern void vfs_write(ipc_callid_t, ipc_call_t *);
  262. extern void vfs_seek(ipc_callid_t, ipc_call_t *);
  263. extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
  264.  
  265. #endif
  266.  
  267. /**
  268.  * @}
  269.  */
  270.