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2520 jermar 1
/*
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 * Copyright (c) 2008 Jakub Jermar
2520 jermar 3
 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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/** @addtogroup fs
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 * @{
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 */ 
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#ifndef VFS_VFS_H_
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#define VFS_VFS_H_
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2523 jermar 36
#include <ipc/ipc.h>
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#include <libadt/list.h>
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#include <atomic.h>
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#include <rwlock.h>
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#include <sys/types.h>
2550 cejka 41
#include <bool.h>
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#define dprintf(...)	printf(__VA_ARGS__)
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2550 cejka 45
#define VFS_FIRST	IPC_FIRST_USER_METHOD
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#define IPC_METHOD_TO_VFS_OP(m)	((m) - VFS_FIRST)	
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typedef enum {
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	VFS_READ = VFS_FIRST,
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	VFS_WRITE,
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	VFS_TRUNCATE,
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	VFS_MOUNT,
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	VFS_UNMOUNT,
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	VFS_LAST_CMN,	/* keep this the last member of this enum */
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} vfs_request_cmn_t;
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typedef enum {
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	VFS_LOOKUP = VFS_LAST_CMN,
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	VFS_DESTROY,
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	VFS_LAST_CLNT,	/* keep this the last member of this enum */
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} vfs_request_clnt_t;
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typedef enum {
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	VFS_REGISTER = VFS_LAST_CMN,
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	VFS_OPEN,
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	VFS_CLOSE,
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	VFS_SEEK,
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	VFS_MKDIR,
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	VFS_UNLINK,
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	VFS_RENAME,
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	VFS_LAST_SRV,	/* keep this the last member of this enum */
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} vfs_request_srv_t;
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75
 
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/**
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 * An instance of this structure is associated with a particular FS operation.
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 * It tells VFS if the FS supports the operation or maybe if a default one
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 * should be used.
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 */
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typedef enum {
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	VFS_OP_NULL = 0,
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	VFS_OP_DEFAULT,
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	VFS_OP_DEFINED
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} vfs_op_t;
86
 
87
#define FS_NAME_MAXLEN	20
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89
/**
90
 * A structure like this is passed to VFS by each individual FS upon its
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 * registration. It assosiates a human-readable identifier with each
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 * registered FS. More importantly, through this structure, the FS announces
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 * what operations it supports.
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 */
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typedef struct {
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	/** Unique identifier of the fs. */
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	char name[FS_NAME_MAXLEN + 1];
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99
	/** Operations. */
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	vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
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} vfs_info_t;
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2540 jermar 103
/**
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 * A structure like this will be allocated for each registered file system.
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 */
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typedef struct {
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	link_t fs_link;
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	vfs_info_t vfs_info;
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	int fs_handle;
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	atomic_t phone_futex;	/**< Phone serializing futex. */
2527 jermar 111
	ipcarg_t phone;
2526 jermar 112
} fs_info_t;
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/**
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 * VFS_PAIR uniquely represents a file system instance.
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 */
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#define VFS_PAIR	\
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	int fs_handle;	\
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	int dev_handle;	
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/**
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 * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
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 * doesn't contain any state. For a stateful structure, see vfs_node_t.
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 *
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 * @note	fs_handle, dev_handle and index are meant to be returned in one
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 *		IPC reply.
127
 */
2587 jermar 128
#define VFS_TRIPLET	\
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	VFS_PAIR;	\
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	uint64_t index;
131
 
2540 jermar 132
typedef struct {
2587 jermar 133
	VFS_PAIR;
134
} vfs_pair_t;
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136
typedef struct {
137
	VFS_TRIPLET;
138
} vfs_triplet_t;
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/*
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 * Lookup flags.
142
 */
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/**
2735 jermar 144
 * No lookup flags used.
145
 */
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#define L_NONE		0
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/**
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 * Lookup will succeed only if the object is a regular file.  If L_CREATE is
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 * specified, an empty file will be created. This flag is mutually exclusive
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 * with L_DIRECTORY.
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 */
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#define L_FILE		1
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/**
154
 * Lookup wil succeed only if the object is a directory. If L_CREATE is
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 * specified, an empty directory will be created. This flag is mutually
156
 * exclusive with L_FILE.
157
 */
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#define L_DIRECTORY	2
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/**
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
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/**
169
 * L_DESTROY is used to remove leaves from the file system namespace. This flag
170
 * cannot be passed directly by the client, but will be set by VFS during
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 * VFS_UNLINK.
172
 */
173
#define L_DESTROY	16
2700 jermar 174
 
2691 jermar 175
typedef struct {
176
	vfs_triplet_t triplet;
177
	size_t size;
2730 jermar 178
	unsigned lnkcnt;
2691 jermar 179
} vfs_lookup_res_t;
180
 
2587 jermar 181
/**
182
 * Instances of this type represent an active, in-memory VFS node and any state
183
 * which may be associated with it.
184
 */
185
typedef struct {
186
	VFS_TRIPLET;		/**< Identity of the node. */
2730 jermar 187
 
188
	/**
189
	 * Usage counter.  This includes, but is not limited to, all vfs_file_t
190
	 * structures that reference this node.
191
	 */
192
	unsigned refcnt;
193
 
194
	/** Number of names this node has in the file system namespace. */
195
	unsigned lnkcnt;
196
 
2593 jermar 197
	link_t nh_link;		/**< Node hash-table link. */
2684 jermar 198
	size_t size;		/**< Cached size of the file. */
2679 jermar 199
 
2682 jermar 200
	/**
201
	 * Holding this rwlock prevents modifications of the node's contents.
202
	 */
203
	rwlock_t contents_rwlock;
2540 jermar 204
} vfs_node_t;
205
 
206
/**
207
 * Instances of this type represent an open file. If the file is opened by more
208
 * than one task, there will be a separate structure allocated for each task.
209
 */
210
typedef struct {
2683 jermar 211
	/** Serializes access to this open file. */
212
	futex_t lock;
213
 
2540 jermar 214
	vfs_node_t *node;
215
 
216
	/** Number of file handles referencing this file. */
2593 jermar 217
	unsigned refcnt;
2540 jermar 218
 
2709 jermar 219
	/** Append on write. */
220
	bool append;
221
 
2540 jermar 222
	/** Current position in the file. */
223
	off_t pos;
224
} vfs_file_t;
225
 
2542 jermar 226
extern link_t fs_head;		/**< List of registered file systems. */
2535 jermar 227
 
2587 jermar 228
extern vfs_triplet_t rootfs;	/**< Root node of the root file system. */
2535 jermar 229
 
2542 jermar 230
#define MAX_PATH_LEN		(64 * 1024)
231
 
232
#define PLB_SIZE		(2 * MAX_PATH_LEN)
233
 
234
/** Each instance of this type describes one path lookup in progress. */
235
typedef struct {
236
	link_t	plb_link;	/**< Active PLB entries list link. */
237
	unsigned index;		/**< Index of the first character in PLB. */
238
	size_t len;		/**< Number of characters in this PLB entry. */
239
} plb_entry_t;
240
 
241
extern atomic_t plb_futex;	/**< Futex protecting plb and plb_head. */
242
extern uint8_t *plb;		/**< Path Lookup Buffer */
243
extern link_t plb_head;		/**< List of active PLB entries. */
244
 
2681 jermar 245
/** Holding this rwlock prevents changes in file system namespace. */ 
246
extern rwlock_t namespace_rwlock;
2593 jermar 247
 
2546 jermar 248
extern int vfs_grab_phone(int);
249
extern void vfs_release_phone(int);
250
 
2552 jermar 251
extern int fs_name_to_handle(char *, bool);
2548 jermar 252
 
2752 jermar 253
extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *, vfs_pair_t *);
2593 jermar 254
 
2596 jermar 255
extern bool vfs_nodes_init(void);
2691 jermar 256
extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
2593 jermar 257
extern void vfs_node_put(vfs_node_t *);
2544 jermar 258
 
2596 jermar 259
#define MAX_OPEN_FILES	128
260
 
2593 jermar 261
extern bool vfs_files_init(void);
262
extern vfs_file_t *vfs_file_get(int);
263
extern int vfs_fd_alloc(void);
264
extern void vfs_fd_free(int);
265
 
266
extern void vfs_file_addref(vfs_file_t *);
267
extern void vfs_file_delref(vfs_file_t *);
268
 
269
extern void vfs_node_addref(vfs_node_t *);
270
extern void vfs_node_delref(vfs_node_t *);
271
 
2542 jermar 272
extern void vfs_register(ipc_callid_t, ipc_call_t *);
2544 jermar 273
extern void vfs_mount(ipc_callid_t, ipc_call_t *);
2560 jermar 274
extern void vfs_open(ipc_callid_t, ipc_call_t *);
2734 jermar 275
extern void vfs_close(ipc_callid_t, ipc_call_t *);
2625 jermar 276
extern void vfs_read(ipc_callid_t, ipc_call_t *);
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extern void vfs_write(ipc_callid_t, ipc_call_t *);
2684 jermar 278
extern void vfs_seek(ipc_callid_t, ipc_call_t *);
2693 jermar 279
extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
2707 jermar 280
extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
2735 jermar 281
extern void vfs_unlink(ipc_callid_t, ipc_call_t *);
2542 jermar 282
 
2520 jermar 283
#endif
284
 
285
/**
286
 * @}
2523 jermar 287
 */