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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_READ = VFS_FIRST,
  51.     VFS_WRITE,
  52.     VFS_TRUNCATE,
  53.     VFS_MOUNT,
  54.     VFS_UNMOUNT,
  55.     VFS_LAST_CMN,   /* keep this the last member of this enum */
  56. } vfs_request_cmn_t;
  57.  
  58. typedef enum {
  59.     VFS_LOOKUP = VFS_LAST_CMN,
  60.     VFS_FREE,
  61.     VFS_LAST_CLNT,  /* keep this the last member of this enum */
  62. } vfs_request_clnt_t;
  63.  
  64. typedef enum {
  65.     VFS_REGISTER = VFS_LAST_CMN,
  66.     VFS_OPEN,
  67.     VFS_CLOSE,
  68.     VFS_SEEK,
  69.     VFS_MKDIR,
  70.     VFS_UNLINK,
  71.     VFS_RENAME,
  72.     VFS_LAST_SRV,   /* keep this the last member of this enum */
  73. } vfs_request_srv_t;
  74.  
  75.  
  76. /**
  77.  * An instance of this structure is associated with a particular FS operation.
  78.  * It tells VFS if the FS supports the operation or maybe if a default one
  79.  * should be used.
  80.  */
  81. typedef enum {
  82.     VFS_OP_NULL = 0,
  83.     VFS_OP_DEFAULT,
  84.     VFS_OP_DEFINED
  85. } vfs_op_t;
  86.  
  87. #define FS_NAME_MAXLEN  20
  88.  
  89. /**
  90.  * A structure like this is passed to VFS by each individual FS upon its
  91.  * registration. It assosiates a human-readable identifier with each
  92.  * registered FS. More importantly, through this structure, the FS announces
  93.  * what operations it supports.
  94.  */
  95. typedef struct {
  96.     /** Unique identifier of the fs. */
  97.     char name[FS_NAME_MAXLEN + 1];
  98.    
  99.     /** Operations. */
  100.     vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
  101. } vfs_info_t;
  102.  
  103. /**
  104.  * A structure like this will be allocated for each registered file system.
  105.  */
  106. typedef struct {
  107.     link_t fs_link;
  108.     vfs_info_t vfs_info;
  109.     int fs_handle;
  110.     atomic_t phone_futex;   /**< Phone serializing futex. */
  111.     ipcarg_t phone;
  112. } fs_info_t;
  113.  
  114. /**
  115.  * VFS_PAIR uniquely represents a file system instance.
  116.  */
  117. #define VFS_PAIR    \
  118.     int fs_handle;  \
  119.     int dev_handle;
  120.  
  121. /**
  122.  * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
  123.  * doesn't contain any state. For a stateful structure, see vfs_node_t.
  124.  *
  125.  * @note    fs_handle, dev_handle and index are meant to be returned in one
  126.  *      IPC reply.
  127.  */
  128. #define VFS_TRIPLET \
  129.     VFS_PAIR;   \
  130.     uint64_t index;
  131.  
  132. typedef struct {
  133.     VFS_PAIR;
  134. } vfs_pair_t;
  135.  
  136. typedef struct {
  137.     VFS_TRIPLET;
  138. } vfs_triplet_t;
  139.  
  140. /*
  141.  * Lookup flags.
  142.  */
  143. /**
  144.  * Lookup will succeed only if the object is a regular file.  If L_CREATE is
  145.  * specified, an empty file will be created. This flag is mutually exclusive
  146.  * with L_DIRECTORY.
  147.  */
  148. #define L_FILE      1
  149. /**
  150.  * Lookup wil succeed only if the object is a directory. If L_CREATE is
  151.  * specified, an empty directory will be created. This flag is mutually
  152.  * exclusive with L_FILE.
  153.  */
  154. #define L_DIRECTORY 2
  155. /**
  156.  * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
  157.  * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
  158.  */
  159. #define L_EXCLUSIVE 4
  160. /**
  161.  * L_CREATE is used for creating both regular files and directories.
  162.  */
  163. #define L_CREATE    8
  164. /**
  165.  * L_DESTROY is used to remove leaves from the file system namespace. This flag
  166.  * cannot be passed directly by the client, but will be set by VFS during
  167.  * VFS_UNLINK.
  168.  */
  169. #define L_DESTROY   16
  170.  
  171. typedef struct {
  172.     vfs_triplet_t triplet;
  173.     size_t size;
  174.     unsigned lnkcnt;
  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.  
  184.     /**
  185.      * Usage counter.  This includes, but is not limited to, all vfs_file_t
  186.      * structures that reference this node.
  187.      */
  188.     unsigned refcnt;
  189.    
  190.     /** Number of names this node has in the file system namespace. */
  191.     unsigned lnkcnt;
  192.  
  193.     link_t nh_link;     /**< Node hash-table link. */
  194.     size_t size;        /**< Cached size of the file. */
  195.  
  196.     /**
  197.      * Holding this rwlock prevents modifications of the node's contents.
  198.      */
  199.     rwlock_t contents_rwlock;
  200. } vfs_node_t;
  201.  
  202. /**
  203.  * Instances of this type represent an open file. If the file is opened by more
  204.  * than one task, there will be a separate structure allocated for each task.
  205.  */
  206. typedef struct {
  207.     /** Serializes access to this open file. */
  208.     futex_t lock;
  209.  
  210.     vfs_node_t *node;
  211.    
  212.     /** Number of file handles referencing this file. */
  213.     unsigned refcnt;
  214.  
  215.     /** Append on write. */
  216.     bool append;
  217.  
  218.     /** Current position in the file. */
  219.     off_t pos;
  220. } vfs_file_t;
  221.  
  222. extern link_t fs_head;      /**< List of registered file systems. */
  223.  
  224. extern vfs_triplet_t rootfs;    /**< Root node of the root file system. */
  225.  
  226. #define MAX_PATH_LEN        (64 * 1024)
  227.  
  228. #define PLB_SIZE        (2 * MAX_PATH_LEN)
  229.  
  230. /** Each instance of this type describes one path lookup in progress. */
  231. typedef struct {
  232.     link_t  plb_link;   /**< Active PLB entries list link. */
  233.     unsigned index;     /**< Index of the first character in PLB. */
  234.     size_t len;     /**< Number of characters in this PLB entry. */
  235. } plb_entry_t;
  236.  
  237. extern atomic_t plb_futex;  /**< Futex protecting plb and plb_head. */
  238. extern uint8_t *plb;        /**< Path Lookup Buffer */
  239. extern link_t plb_head;     /**< List of active PLB entries. */
  240.  
  241. /** Holding this rwlock prevents changes in file system namespace. */
  242. extern rwlock_t namespace_rwlock;
  243.  
  244. extern int vfs_grab_phone(int);
  245. extern void vfs_release_phone(int);
  246.  
  247. extern int fs_name_to_handle(char *, bool);
  248.  
  249. extern int vfs_lookup_internal(char *, size_t, int, vfs_lookup_res_t *,
  250.     vfs_pair_t *);
  251.  
  252. extern bool vfs_nodes_init(void);
  253. extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
  254. extern void vfs_node_put(vfs_node_t *);
  255.  
  256. #define MAX_OPEN_FILES  128
  257.  
  258. extern bool vfs_files_init(void);
  259. extern vfs_file_t *vfs_file_get(int);
  260. extern int vfs_fd_alloc(void);
  261. extern void vfs_fd_free(int);
  262.  
  263. extern void vfs_file_addref(vfs_file_t *);
  264. extern void vfs_file_delref(vfs_file_t *);
  265.  
  266. extern void vfs_node_addref(vfs_node_t *);
  267. extern void vfs_node_delref(vfs_node_t *);
  268.  
  269. extern void vfs_register(ipc_callid_t, ipc_call_t *);
  270. extern void vfs_mount(ipc_callid_t, ipc_call_t *);
  271. extern void vfs_open(ipc_callid_t, ipc_call_t *);
  272. extern void vfs_close(ipc_callid_t, ipc_call_t *);
  273. extern void vfs_read(ipc_callid_t, ipc_call_t *);
  274. extern void vfs_write(ipc_callid_t, ipc_call_t *);
  275. extern void vfs_seek(ipc_callid_t, ipc_call_t *);
  276. extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
  277. extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
  278.  
  279. #endif
  280.  
  281. /**
  282.  * @}
  283.  */
  284.