source: mainline/uspace/srv/vfs/vfs.h@ cad9c72

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since cad9c72 was cad9c72, checked in by Jakub Jermar <jakub@…>, 17 years ago

Make a distinction between VFS operations that are common to VFS and FS
implementations, operations that are VFS only and operations that are FS
implementations only.
  • Property mode set to 100644
File size: 6.3 KB
Line 
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
49typedef 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
65typedef 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
70typedef 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 */
82typedef 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 */
96typedef 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 */
107typedef 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
133typedef struct {
134 VFS_PAIR;
135} vfs_pair_t;
136
137typedef struct {
138 VFS_TRIPLET;
139} vfs_triplet_t;
140
141/**
142 * Instances of this type represent an active, in-memory VFS node and any state
143 * which may be associated with it.
144 */
145typedef struct {
146 VFS_TRIPLET; /**< Identity of the node. */
147 unsigned refcnt; /**< Usage counter. */
148 link_t nh_link; /**< Node hash-table link. */
149 size_t size; /**< Cached size of the file. */
150
151 /**
152 * Holding this rwlock prevents modifications of the node's contents.
153 */
154 rwlock_t contents_rwlock;
155} vfs_node_t;
156
157/**
158 * Instances of this type represent an open file. If the file is opened by more
159 * than one task, there will be a separate structure allocated for each task.
160 */
161typedef struct {
162 /** Serializes access to this open file. */
163 futex_t lock;
164
165 vfs_node_t *node;
166
167 /** Number of file handles referencing this file. */
168 unsigned refcnt;
169
170 /** Current position in the file. */
171 off_t pos;
172} vfs_file_t;
173
174extern link_t fs_head; /**< List of registered file systems. */
175
176extern vfs_triplet_t rootfs; /**< Root node of the root file system. */
177
178#define MAX_PATH_LEN (64 * 1024)
179
180#define PLB_SIZE (2 * MAX_PATH_LEN)
181
182/** Each instance of this type describes one path lookup in progress. */
183typedef struct {
184 link_t plb_link; /**< Active PLB entries list link. */
185 unsigned index; /**< Index of the first character in PLB. */
186 size_t len; /**< Number of characters in this PLB entry. */
187} plb_entry_t;
188
189extern atomic_t plb_futex; /**< Futex protecting plb and plb_head. */
190extern uint8_t *plb; /**< Path Lookup Buffer */
191extern link_t plb_head; /**< List of active PLB entries. */
192
193/** Holding this rwlock prevents changes in file system namespace. */
194extern rwlock_t namespace_rwlock;
195
196extern int vfs_grab_phone(int);
197extern void vfs_release_phone(int);
198
199extern int fs_name_to_handle(char *, bool);
200
201extern int vfs_lookup_internal(char *, size_t, vfs_triplet_t *, size_t *,
202 vfs_pair_t *);
203
204extern bool vfs_nodes_init(void);
205extern vfs_node_t *vfs_node_get(vfs_triplet_t *, size_t);
206extern void vfs_node_put(vfs_node_t *);
207
208#define MAX_OPEN_FILES 128
209
210extern bool vfs_files_init(void);
211extern vfs_file_t *vfs_file_get(int);
212extern int vfs_fd_alloc(void);
213extern void vfs_fd_free(int);
214
215extern void vfs_file_addref(vfs_file_t *);
216extern void vfs_file_delref(vfs_file_t *);
217
218extern void vfs_node_addref(vfs_node_t *);
219extern void vfs_node_delref(vfs_node_t *);
220
221extern void vfs_register(ipc_callid_t, ipc_call_t *);
222extern void vfs_mount(ipc_callid_t, ipc_call_t *);
223extern void vfs_open(ipc_callid_t, ipc_call_t *);
224extern void vfs_read(ipc_callid_t, ipc_call_t *);
225extern void vfs_write(ipc_callid_t, ipc_call_t *);
226extern void vfs_seek(ipc_callid_t, ipc_call_t *);
227
228#endif
229
230/**
231 * @}
232 */
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