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