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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 <futex.h>
  39. #include <rwlock.h>
  40. #include <sys/types.h>
  41. #include <bool.h>
  42.  
  43. // FIXME: according to CONFIG_DEBUG
  44. // #define dprintf(...) printf(__VA_ARGS__)
  45.  
  46. #define dprintf(...)
  47.  
  48. #define VFS_FIRST   IPC_FIRST_USER_METHOD
  49.  
  50. #define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)  
  51.  
  52. /* Basic types. */
  53. typedef int16_t fs_handle_t;
  54. typedef int16_t dev_handle_t;
  55. typedef uint32_t fs_index_t;
  56.  
  57. typedef enum {
  58.     VFS_READ = VFS_FIRST,
  59.     VFS_WRITE,
  60.     VFS_TRUNCATE,
  61.     VFS_MOUNT,
  62.     VFS_UNMOUNT,
  63.     VFS_LAST_CMN,   /* keep this the last member of this enum */
  64. } vfs_request_cmn_t;
  65.  
  66. typedef enum {
  67.     VFS_LOOKUP = VFS_LAST_CMN,
  68.     VFS_MOUNTED,
  69.     VFS_DESTROY,
  70.     VFS_LAST_CLNT,  /* keep this the last member of this enum */
  71. } vfs_request_clnt_t;
  72.  
  73. typedef enum {
  74.     VFS_REGISTER = VFS_LAST_CMN,
  75.     VFS_OPEN,
  76.     VFS_CLOSE,
  77.     VFS_SEEK,
  78.     VFS_MKDIR,
  79.     VFS_UNLINK,
  80.     VFS_RENAME,
  81.     VFS_LAST_SRV,   /* keep this the last member of this enum */
  82. } vfs_request_srv_t;
  83.  
  84.  
  85. /**
  86.  * An instance of this structure is associated with a particular FS operation.
  87.  * It tells VFS if the FS supports the operation or maybe if a default one
  88.  * should be used.
  89.  */
  90. typedef enum {
  91.     VFS_OP_NULL = 0,
  92.     VFS_OP_DEFAULT,
  93.     VFS_OP_DEFINED
  94. } vfs_op_t;
  95.  
  96. #define FS_NAME_MAXLEN  20
  97.  
  98. /**
  99.  * A structure like this is passed to VFS by each individual FS upon its
  100.  * registration. It assosiates a human-readable identifier with each
  101.  * registered FS. More importantly, through this structure, the FS announces
  102.  * what operations it supports.
  103.  */
  104. typedef struct {
  105.     /** Unique identifier of the fs. */
  106.     char name[FS_NAME_MAXLEN + 1];
  107.    
  108.     /** Operations. */
  109.     vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
  110. } vfs_info_t;
  111.  
  112. /**
  113.  * A structure like this will be allocated for each registered file system.
  114.  */
  115. typedef struct {
  116.     link_t fs_link;
  117.     vfs_info_t vfs_info;
  118.     fs_handle_t fs_handle;
  119.     futex_t phone_futex;    /**< Phone serializing futex. */
  120.     ipcarg_t phone;
  121. } fs_info_t;
  122.  
  123. /**
  124.  * VFS_PAIR uniquely represents a file system instance.
  125.  */
  126. #define VFS_PAIR        \
  127.     fs_handle_t fs_handle;  \
  128.     dev_handle_t dev_handle;
  129.  
  130. /**
  131.  * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
  132.  * doesn't contain any state. For a stateful structure, see vfs_node_t.
  133.  *
  134.  * @note    fs_handle, dev_handle and index are meant to be returned in one
  135.  *      IPC reply.
  136.  */
  137. #define VFS_TRIPLET \
  138.     VFS_PAIR;   \
  139.     fs_index_t index;
  140.  
  141. typedef struct {
  142.     VFS_PAIR;
  143. } vfs_pair_t;
  144.  
  145. typedef struct {
  146.     VFS_TRIPLET;
  147. } vfs_triplet_t;
  148.  
  149. /*
  150.  * Lookup flags.
  151.  */
  152. /**
  153.  * No lookup flags used.
  154.  */
  155. #define L_NONE      0
  156. /**
  157.  * Lookup will succeed only if the object is a regular file.  If L_CREATE is
  158.  * specified, an empty file will be created. This flag is mutually exclusive
  159.  * with L_DIRECTORY.
  160.  */
  161. #define L_FILE      1
  162. /**
  163.  * Lookup wil succeed only if the object is a directory. If L_CREATE is
  164.  * specified, an empty directory will be created. This flag is mutually
  165.  * exclusive with L_FILE.
  166.  */
  167. #define L_DIRECTORY 2
  168. /**
  169.  * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
  170.  * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
  171.  */
  172. #define L_EXCLUSIVE 4
  173. /**
  174.  * L_CREATE is used for creating both regular files and directories.
  175.  */
  176. #define L_CREATE    8
  177. /**
  178.  * L_LINK is used for linking to an already existing nodes.
  179.  */
  180. #define L_LINK      16
  181. /**
  182.  * L_UNLINK is used to remove leaves from the file system namespace. This flag
  183.  * cannot be passed directly by the client, but will be set by VFS during
  184.  * VFS_UNLINK.
  185.  */
  186. #define L_UNLINK    32 
  187. /**
  188.  * L_PARENT performs a lookup but returns the triplet of the parent node.
  189.  * This flag may not be combined with any other lookup flag.
  190.  */
  191. #define L_PARENT    64 
  192.  
  193. typedef struct {
  194.     vfs_triplet_t triplet;
  195.     size_t size;
  196.     unsigned lnkcnt;
  197. } vfs_lookup_res_t;
  198.  
  199. /**
  200.  * Instances of this type represent an active, in-memory VFS node and any state
  201.  * which may be associated with it.
  202.  */
  203. typedef struct {
  204.     VFS_TRIPLET;        /**< Identity of the node. */
  205.  
  206.     /**
  207.      * Usage counter.  This includes, but is not limited to, all vfs_file_t
  208.      * structures that reference this node.
  209.      */
  210.     unsigned refcnt;
  211.    
  212.     /** Number of names this node has in the file system namespace. */
  213.     unsigned lnkcnt;
  214.  
  215.     link_t nh_link;     /**< Node hash-table link. */
  216.     size_t size;        /**< Cached size if the node is a file. */
  217.  
  218.     /**
  219.      * Holding this rwlock prevents modifications of the node's contents.
  220.      */
  221.     rwlock_t contents_rwlock;
  222. } vfs_node_t;
  223.  
  224. /**
  225.  * Instances of this type represent an open file. If the file is opened by more
  226.  * than one task, there will be a separate structure allocated for each task.
  227.  */
  228. typedef struct {
  229.     /** Serializes access to this open file. */
  230.     futex_t lock;
  231.  
  232.     vfs_node_t *node;
  233.    
  234.     /** Number of file handles referencing this file. */
  235.     unsigned refcnt;
  236.  
  237.     /** Append on write. */
  238.     bool append;
  239.  
  240.     /** Current position in the file. */
  241.     off_t pos;
  242. } vfs_file_t;
  243.  
  244. extern futex_t nodes_futex;
  245.  
  246. extern link_t fs_head;      /**< List of registered file systems. */
  247.  
  248. extern vfs_pair_t rootfs;   /**< Root file system. */
  249.  
  250. #define MAX_PATH_LEN        (64 * 1024)
  251.  
  252. #define PLB_SIZE        (2 * MAX_PATH_LEN)
  253.  
  254. /** Each instance of this type describes one path lookup in progress. */
  255. typedef struct {
  256.     link_t  plb_link;   /**< Active PLB entries list link. */
  257.     unsigned index;     /**< Index of the first character in PLB. */
  258.     size_t len;     /**< Number of characters in this PLB entry. */
  259. } plb_entry_t;
  260.  
  261. extern futex_t plb_futex;   /**< Futex protecting plb and plb_head. */
  262. extern uint8_t *plb;        /**< Path Lookup Buffer */
  263. extern link_t plb_head;     /**< List of active PLB entries. */
  264.  
  265. /** Holding this rwlock prevents changes in file system namespace. */
  266. extern rwlock_t namespace_rwlock;
  267.  
  268. extern int vfs_grab_phone(fs_handle_t);
  269. extern void vfs_release_phone(int);
  270.  
  271. extern fs_handle_t fs_name_to_handle(char *, bool);
  272.  
  273. extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *, vfs_pair_t *,
  274.     ...);
  275.  
  276. extern bool vfs_nodes_init(void);
  277. extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
  278. extern void vfs_node_put(vfs_node_t *);
  279.  
  280. #define MAX_OPEN_FILES  128
  281.  
  282. extern bool vfs_files_init(void);
  283. extern vfs_file_t *vfs_file_get(int);
  284. extern int vfs_fd_alloc(void);
  285. extern int vfs_fd_free(int);
  286.  
  287. extern void vfs_file_addref(vfs_file_t *);
  288. extern void vfs_file_delref(vfs_file_t *);
  289.  
  290. extern void vfs_node_addref(vfs_node_t *);
  291. extern void vfs_node_delref(vfs_node_t *);
  292.  
  293. extern void vfs_register(ipc_callid_t, ipc_call_t *);
  294. extern void vfs_mount(ipc_callid_t, ipc_call_t *);
  295. extern void vfs_open(ipc_callid_t, ipc_call_t *);
  296. extern void vfs_close(ipc_callid_t, ipc_call_t *);
  297. extern void vfs_read(ipc_callid_t, ipc_call_t *);
  298. extern void vfs_write(ipc_callid_t, ipc_call_t *);
  299. extern void vfs_seek(ipc_callid_t, ipc_call_t *);
  300. extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
  301. extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
  302. extern void vfs_unlink(ipc_callid_t, ipc_call_t *);
  303. extern void vfs_rename(ipc_callid_t, ipc_call_t *);
  304.  
  305. #endif
  306.  
  307. /**
  308.  * @}
  309.  */
  310.