source: mainline/uspace/srv/vfs/vfs.h@ 07deef5

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 07deef5 was c31d773, checked in by Jakub Jermar <jakub@…>, 18 years ago

Grab the nodes_futex when manipulating node link counts in rename() and
_unlink().

Fix VFS futex definitions and declarations by replacing atomic_t by futex_t.
  • Property mode set to 100644
File size: 8.0 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 <futex.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_READ = VFS_FIRST,
51 VFS_WRITE,
52 VFS_TRUNCATE,
53 VFS_MOUNT,
54 VFS_UNMOUNT,
55 VFS_LAST_CMN, /* keep this the last member of this enum */
56} vfs_request_cmn_t;
57
58typedef enum {
59 VFS_LOOKUP = VFS_LAST_CMN,
60 VFS_DESTROY,
61 VFS_LAST_CLNT, /* keep this the last member of this enum */
62} vfs_request_clnt_t;
63
64typedef enum {
65 VFS_REGISTER = VFS_LAST_CMN,
66 VFS_OPEN,
67 VFS_CLOSE,
68 VFS_SEEK,
69 VFS_MKDIR,
70 VFS_UNLINK,
71 VFS_RENAME,
72 VFS_LAST_SRV, /* keep this the last member of this enum */
73} vfs_request_srv_t;
74
75
76/**
77 * An instance of this structure is associated with a particular FS operation.
78 * It tells VFS if the FS supports the operation or maybe if a default one
79 * should be used.
80 */
81typedef enum {
82 VFS_OP_NULL = 0,
83 VFS_OP_DEFAULT,
84 VFS_OP_DEFINED
85} vfs_op_t;
86
87#define FS_NAME_MAXLEN 20
88
89/**
90 * A structure like this is passed to VFS by each individual FS upon its
91 * registration. It assosiates a human-readable identifier with each
92 * registered FS. More importantly, through this structure, the FS announces
93 * what operations it supports.
94 */
95typedef struct {
96 /** Unique identifier of the fs. */
97 char name[FS_NAME_MAXLEN + 1];
98
99 /** Operations. */
100 vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
101} vfs_info_t;
102
103/**
104 * A structure like this will be allocated for each registered file system.
105 */
106typedef struct {
107 link_t fs_link;
108 vfs_info_t vfs_info;
109 int fs_handle;
110 futex_t phone_futex; /**< Phone serializing futex. */
111 ipcarg_t phone;
112} fs_info_t;
113
114/**
115 * VFS_PAIR uniquely represents a file system instance.
116 */
117#define VFS_PAIR \
118 int fs_handle; \
119 int dev_handle;
120
121/**
122 * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
123 * doesn't contain any state. For a stateful structure, see vfs_node_t.
124 *
125 * @note fs_handle, dev_handle and index are meant to be returned in one
126 * IPC reply.
127 */
128#define VFS_TRIPLET \
129 VFS_PAIR; \
130 uint64_t index;
131
132typedef struct {
133 VFS_PAIR;
134} vfs_pair_t;
135
136typedef struct {
137 VFS_TRIPLET;
138} vfs_triplet_t;
139
140/*
141 * Lookup flags.
142 */
143/**
144 * No lookup flags used.
145 */
146#define L_NONE 0
147/**
148 * Lookup will succeed only if the object is a regular file. If L_CREATE is
149 * specified, an empty file will be created. This flag is mutually exclusive
150 * with L_DIRECTORY.
151 */
152#define L_FILE 1
153/**
154 * Lookup wil succeed only if the object is a directory. If L_CREATE is
155 * specified, an empty directory will be created. This flag is mutually
156 * exclusive with L_FILE.
157 */
158#define L_DIRECTORY 2
159/**
160 * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
161 * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
162 */
163#define L_EXCLUSIVE 4
164/**
165 * L_CREATE is used for creating both regular files and directories.
166 */
167#define L_CREATE 8
168/**
169 * L_LINK is used for linking to an already existing nodes.
170 */
171#define L_LINK 16
172/**
173 * L_UNLINK is used to remove leaves from the file system namespace. This flag
174 * cannot be passed directly by the client, but will be set by VFS during
175 * VFS_UNLINK.
176 */
177#define L_UNLINK 32
178/**
179 * L_PARENT performs a lookup but returns the triplet of the parent node.
180 * This flag may not be combined with any other lookup flag.
181 */
182#define L_PARENT 64
183
184typedef struct {
185 vfs_triplet_t triplet;
186 size_t size;
187 unsigned lnkcnt;
188} vfs_lookup_res_t;
189
190/**
191 * Instances of this type represent an active, in-memory VFS node and any state
192 * which may be associated with it.
193 */
194typedef struct {
195 VFS_TRIPLET; /**< Identity of the node. */
196
197 /**
198 * Usage counter. This includes, but is not limited to, all vfs_file_t
199 * structures that reference this node.
200 */
201 unsigned refcnt;
202
203 /** Number of names this node has in the file system namespace. */
204 unsigned lnkcnt;
205
206 link_t nh_link; /**< Node hash-table link. */
207 size_t size; /**< Cached size of the file. */
208
209 /**
210 * Holding this rwlock prevents modifications of the node's contents.
211 */
212 rwlock_t contents_rwlock;
213} vfs_node_t;
214
215/**
216 * Instances of this type represent an open file. If the file is opened by more
217 * than one task, there will be a separate structure allocated for each task.
218 */
219typedef struct {
220 /** Serializes access to this open file. */
221 futex_t lock;
222
223 vfs_node_t *node;
224
225 /** Number of file handles referencing this file. */
226 unsigned refcnt;
227
228 /** Append on write. */
229 bool append;
230
231 /** Current position in the file. */
232 off_t pos;
233} vfs_file_t;
234
235extern futex_t nodes_futex;
236
237extern link_t fs_head; /**< List of registered file systems. */
238
239extern vfs_triplet_t rootfs; /**< Root node of the root file system. */
240
241#define MAX_PATH_LEN (64 * 1024)
242
243#define PLB_SIZE (2 * MAX_PATH_LEN)
244
245/** Each instance of this type describes one path lookup in progress. */
246typedef struct {
247 link_t plb_link; /**< Active PLB entries list link. */
248 unsigned index; /**< Index of the first character in PLB. */
249 size_t len; /**< Number of characters in this PLB entry. */
250} plb_entry_t;
251
252extern futex_t plb_futex; /**< Futex protecting plb and plb_head. */
253extern uint8_t *plb; /**< Path Lookup Buffer */
254extern link_t plb_head; /**< List of active PLB entries. */
255
256/** Holding this rwlock prevents changes in file system namespace. */
257extern rwlock_t namespace_rwlock;
258
259extern int vfs_grab_phone(int);
260extern void vfs_release_phone(int);
261
262extern int fs_name_to_handle(char *, bool);
263
264extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *, vfs_pair_t *,
265 ...);
266
267extern bool vfs_nodes_init(void);
268extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
269extern void vfs_node_put(vfs_node_t *);
270
271#define MAX_OPEN_FILES 128
272
273extern bool vfs_files_init(void);
274extern vfs_file_t *vfs_file_get(int);
275extern int vfs_fd_alloc(void);
276extern void vfs_fd_free(int);
277
278extern void vfs_file_addref(vfs_file_t *);
279extern void vfs_file_delref(vfs_file_t *);
280
281extern void vfs_node_addref(vfs_node_t *);
282extern void vfs_node_delref(vfs_node_t *);
283
284extern void vfs_register(ipc_callid_t, ipc_call_t *);
285extern void vfs_mount(ipc_callid_t, ipc_call_t *);
286extern void vfs_open(ipc_callid_t, ipc_call_t *);
287extern void vfs_close(ipc_callid_t, ipc_call_t *);
288extern void vfs_read(ipc_callid_t, ipc_call_t *);
289extern void vfs_write(ipc_callid_t, ipc_call_t *);
290extern void vfs_seek(ipc_callid_t, ipc_call_t *);
291extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
292extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
293extern void vfs_unlink(ipc_callid_t, ipc_call_t *);
294extern void vfs_rename(ipc_callid_t, ipc_call_t *);
295
296#endif
297
298/**
299 * @}
300 */
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