source: mainline/uspace/srv/vfs/vfs.h@ 4fb6bf36

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 4fb6bf36 was eb27ce5a, checked in by Jakub Jermar <jakub@…>, 17 years ago

Improve the API for converting (VFS triplets, size) to VFS nodes by introducing
a new type for results of vfs_lookup_internal().
  • Property mode set to 100644
File size: 6.4 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
141typedef struct {
142 vfs_triplet_t triplet;
143 size_t size;
144} vfs_lookup_res_t;
145
146/**
147 * Instances of this type represent an active, in-memory VFS node and any state
148 * which may be associated with it.
149 */
150typedef struct {
151 VFS_TRIPLET; /**< Identity of the node. */
152 unsigned refcnt; /**< Usage counter. */
153 link_t nh_link; /**< Node hash-table link. */
154 size_t size; /**< Cached size of the file. */
155
156 /**
157 * Holding this rwlock prevents modifications of the node's contents.
158 */
159 rwlock_t contents_rwlock;
160} vfs_node_t;
161
162/**
163 * Instances of this type represent an open file. If the file is opened by more
164 * than one task, there will be a separate structure allocated for each task.
165 */
166typedef struct {
167 /** Serializes access to this open file. */
168 futex_t lock;
169
170 vfs_node_t *node;
171
172 /** Number of file handles referencing this file. */
173 unsigned refcnt;
174
175 /** Current position in the file. */
176 off_t pos;
177} vfs_file_t;
178
179extern link_t fs_head; /**< List of registered file systems. */
180
181extern vfs_triplet_t rootfs; /**< Root node of the root file system. */
182
183#define MAX_PATH_LEN (64 * 1024)
184
185#define PLB_SIZE (2 * MAX_PATH_LEN)
186
187/** Each instance of this type describes one path lookup in progress. */
188typedef struct {
189 link_t plb_link; /**< Active PLB entries list link. */
190 unsigned index; /**< Index of the first character in PLB. */
191 size_t len; /**< Number of characters in this PLB entry. */
192} plb_entry_t;
193
194extern atomic_t plb_futex; /**< Futex protecting plb and plb_head. */
195extern uint8_t *plb; /**< Path Lookup Buffer */
196extern link_t plb_head; /**< List of active PLB entries. */
197
198/** Holding this rwlock prevents changes in file system namespace. */
199extern rwlock_t namespace_rwlock;
200
201extern int vfs_grab_phone(int);
202extern void vfs_release_phone(int);
203
204extern int fs_name_to_handle(char *, bool);
205
206extern int vfs_lookup_internal(char *, size_t, vfs_lookup_res_t *,
207 vfs_pair_t *);
208
209extern bool vfs_nodes_init(void);
210extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
211extern void vfs_node_put(vfs_node_t *);
212
213#define MAX_OPEN_FILES 128
214
215extern bool vfs_files_init(void);
216extern vfs_file_t *vfs_file_get(int);
217extern int vfs_fd_alloc(void);
218extern void vfs_fd_free(int);
219
220extern void vfs_file_addref(vfs_file_t *);
221extern void vfs_file_delref(vfs_file_t *);
222
223extern void vfs_node_addref(vfs_node_t *);
224extern void vfs_node_delref(vfs_node_t *);
225
226extern void vfs_register(ipc_callid_t, ipc_call_t *);
227extern void vfs_mount(ipc_callid_t, ipc_call_t *);
228extern void vfs_open(ipc_callid_t, ipc_call_t *);
229extern void vfs_read(ipc_callid_t, ipc_call_t *);
230extern void vfs_write(ipc_callid_t, ipc_call_t *);
231extern void vfs_seek(ipc_callid_t, ipc_call_t *);
232
233#endif
234
235/**
236 * @}
237 */
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