source: mainline/uspace/srv/vfs/vfs.h@ b3c38750

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since b3c38750 was b3c38750, checked in by Jakub Jermar <jakub@…>, 18 years ago

Turn the namespace futex into rwlock.
  • Property mode set to 100644
File size: 5.8 KB
Line 
1/*
2 * Copyright (c) 2007 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_REGISTER = VFS_FIRST,
51 VFS_MOUNT,
52 VFS_UNMOUNT,
53 VFS_LOOKUP,
54 VFS_OPEN,
55 VFS_CREATE,
56 VFS_CLOSE,
57 VFS_READ,
58 VFS_WRITE,
59 VFS_SEEK,
60 VFS_RENAME,
61 VFS_UNLINK,
62 VFS_LAST, /* keep this the last member of the enum */
63} vfs_request_t;
64
65
66/**
67 * An instance of this structure is associated with a particular FS operation.
68 * It tells VFS if the FS supports the operation or maybe if a default one
69 * should be used.
70 */
71typedef enum {
72 VFS_OP_NULL = 0,
73 VFS_OP_DEFAULT,
74 VFS_OP_DEFINED
75} vfs_op_t;
76
77#define FS_NAME_MAXLEN 20
78
79/**
80 * A structure like this is passed to VFS by each individual FS upon its
81 * registration. It assosiates a human-readable identifier with each
82 * registered FS. More importantly, through this structure, the FS announces
83 * what operations it supports.
84 */
85typedef struct {
86 /** Unique identifier of the fs. */
87 char name[FS_NAME_MAXLEN + 1];
88
89 /** Operations. */
90 vfs_op_t ops[VFS_LAST - VFS_FIRST];
91} vfs_info_t;
92
93/**
94 * A structure like this will be allocated for each registered file system.
95 */
96typedef struct {
97 link_t fs_link;
98 vfs_info_t vfs_info;
99 int fs_handle;
100 atomic_t phone_futex; /**< Phone serializing futex. */
101 ipcarg_t phone;
102} fs_info_t;
103
104/**
105 * VFS_PAIR uniquely represents a file system instance.
106 */
107#define VFS_PAIR \
108 int fs_handle; \
109 int dev_handle;
110
111/**
112 * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
113 * doesn't contain any state. For a stateful structure, see vfs_node_t.
114 *
115 * @note fs_handle, dev_handle and index are meant to be returned in one
116 * IPC reply.
117 */
118#define VFS_TRIPLET \
119 VFS_PAIR; \
120 uint64_t index;
121
122typedef struct {
123 VFS_PAIR;
124} vfs_pair_t;
125
126typedef struct {
127 VFS_TRIPLET;
128} vfs_triplet_t;
129
130/**
131 * Instances of this type represent an active, in-memory VFS node and any state
132 * which may be associated with it.
133 */
134typedef struct {
135 VFS_TRIPLET; /**< Identity of the node. */
136 unsigned refcnt; /**< Usage counter. */
137 link_t nh_link; /**< Node hash-table link. */
138
139 /** Holding this rwlock prevents modifications of the node's contents. */
140 atomic_t contents_rwlock;
141} vfs_node_t;
142
143/**
144 * Instances of this type represent an open file. If the file is opened by more
145 * than one task, there will be a separate structure allocated for each task.
146 */
147typedef struct {
148 vfs_node_t *node;
149
150 /** Number of file handles referencing this file. */
151 unsigned refcnt;
152
153 /** Current position in the file. */
154 off_t pos;
155} vfs_file_t;
156
157extern link_t fs_head; /**< List of registered file systems. */
158
159extern vfs_triplet_t rootfs; /**< Root node of the root file system. */
160
161#define MAX_PATH_LEN (64 * 1024)
162
163#define PLB_SIZE (2 * MAX_PATH_LEN)
164
165/** Each instance of this type describes one path lookup in progress. */
166typedef struct {
167 link_t plb_link; /**< Active PLB entries list link. */
168 unsigned index; /**< Index of the first character in PLB. */
169 size_t len; /**< Number of characters in this PLB entry. */
170} plb_entry_t;
171
172extern atomic_t plb_futex; /**< Futex protecting plb and plb_head. */
173extern uint8_t *plb; /**< Path Lookup Buffer */
174extern link_t plb_head; /**< List of active PLB entries. */
175
176/** Holding this rwlock prevents changes in file system namespace. */
177extern rwlock_t namespace_rwlock;
178
179extern int vfs_grab_phone(int);
180extern void vfs_release_phone(int);
181
182extern int fs_name_to_handle(char *, bool);
183
184extern int vfs_lookup_internal(char *, size_t, vfs_triplet_t *, vfs_pair_t *);
185
186extern bool vfs_nodes_init(void);
187extern vfs_node_t *vfs_node_get(vfs_triplet_t *);
188extern void vfs_node_put(vfs_node_t *);
189
190#define MAX_OPEN_FILES 128
191
192extern bool vfs_files_init(void);
193extern vfs_file_t *vfs_file_get(int);
194extern int vfs_fd_alloc(void);
195extern void vfs_fd_free(int);
196
197extern void vfs_file_addref(vfs_file_t *);
198extern void vfs_file_delref(vfs_file_t *);
199
200extern void vfs_node_addref(vfs_node_t *);
201extern void vfs_node_delref(vfs_node_t *);
202
203extern void vfs_register(ipc_callid_t, ipc_call_t *);
204extern void vfs_mount(ipc_callid_t, ipc_call_t *);
205extern void vfs_open(ipc_callid_t, ipc_call_t *);
206extern void vfs_read(ipc_callid_t, ipc_call_t *);
207extern void vfs_write(ipc_callid_t, ipc_call_t *);
208
209#endif
210
211/**
212 * @}
213 */
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