/*
* Copyright (c) 2008 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @addtogroup fs
* @{
*/
#ifndef VFS_VFS_H_
#define VFS_VFS_H_
#include <ipc/ipc.h>
#include <libadt/list.h>
#include <atomic.h>
#include <rwlock.h>
#include <sys/types.h>
#include <bool.h>
#define dprintf(...) printf(__VA_ARGS__)
#define VFS_FIRST IPC_FIRST_USER_METHOD
#define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)
typedef enum {
VFS_READ = VFS_FIRST,
VFS_WRITE,
VFS_TRUNCATE,
VFS_MOUNT,
VFS_UNMOUNT,
VFS_LAST_CMN, /* keep this the last member of this enum */
} vfs_request_cmn_t;
typedef enum {
VFS_LOOKUP = VFS_LAST_CMN,
VFS_FREE,
VFS_LAST_CLNT, /* keep this the last member of this enum */
} vfs_request_clnt_t;
typedef enum {
VFS_REGISTER = VFS_LAST_CMN,
VFS_OPEN,
VFS_CLOSE,
VFS_SEEK,
VFS_MKDIR,
VFS_UNLINK,
VFS_RENAME,
VFS_LAST_SRV, /* keep this the last member of this enum */
} vfs_request_srv_t;
/**
* An instance of this structure is associated with a particular FS operation.
* It tells VFS if the FS supports the operation or maybe if a default one
* should be used.
*/
typedef enum {
VFS_OP_NULL = 0,
VFS_OP_DEFAULT,
VFS_OP_DEFINED
} vfs_op_t;
#define FS_NAME_MAXLEN 20
/**
* A structure like this is passed to VFS by each individual FS upon its
* registration. It assosiates a human-readable identifier with each
* registered FS. More importantly, through this structure, the FS announces
* what operations it supports.
*/
typedef struct {
/** Unique identifier of the fs. */
char name[FS_NAME_MAXLEN + 1];
/** Operations. */
vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
} vfs_info_t;
/**
* A structure like this will be allocated for each registered file system.
*/
typedef struct {
link_t fs_link;
vfs_info_t vfs_info;
int fs_handle;
atomic_t phone_futex; /**< Phone serializing futex. */
ipcarg_t phone;
} fs_info_t;
/**
* VFS_PAIR uniquely represents a file system instance.
*/
#define VFS_PAIR \
int fs_handle; \
int dev_handle;
/**
* VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
* doesn't contain any state. For a stateful structure, see vfs_node_t.
*
* @note fs_handle, dev_handle and index are meant to be returned in one
* IPC reply.
*/
#define VFS_TRIPLET \
VFS_PAIR; \
uint64_t index;
typedef struct {
VFS_PAIR;
} vfs_pair_t;
typedef struct {
VFS_TRIPLET;
} vfs_triplet_t;
/*
* Lookup flags.
*/
/**
* Lookup will succeed only if the object is a regular file. If L_CREATE is
* specified, an empty file will be created. This flag is mutually exclusive
* with L_DIRECTORY.
*/
#define L_FILE 1
/**
* Lookup wil succeed only if the object is a directory. If L_CREATE is
* specified, an empty directory will be created. This flag is mutually
* exclusive with L_FILE.
*/
#define L_DIRECTORY 2
/**
* When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
* object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
*/
#define L_EXCLUSIVE 4
/**
* L_CREATE is used for creating both regular files and directories.
*/
#define L_CREATE 8
/**
* L_DESTROY is used to remove leaves from the file system namespace. This flag
* cannot be passed directly by the client, but will be set by VFS during
* VFS_UNLINK.
*/
#define L_DESTROY 16
typedef struct {
vfs_triplet_t triplet;
size_t size;
unsigned lnkcnt;
} vfs_lookup_res_t;
/**
* Instances of this type represent an active, in-memory VFS node and any state
* which may be associated with it.
*/
typedef struct {
VFS_TRIPLET; /**< Identity of the node. */
/**
* Usage counter. This includes, but is not limited to, all vfs_file_t
* structures that reference this node.
*/
unsigned refcnt;
/** Number of names this node has in the file system namespace. */
unsigned lnkcnt;
link_t nh_link; /**< Node hash-table link. */
size_t size; /**< Cached size of the file. */
/**
* Holding this rwlock prevents modifications of the node's contents.
*/
rwlock_t contents_rwlock;
} vfs_node_t;
/**
* Instances of this type represent an open file. If the file is opened by more
* than one task, there will be a separate structure allocated for each task.
*/
typedef struct {
/** Serializes access to this open file. */
futex_t lock;
vfs_node_t *node;
/** Number of file handles referencing this file. */
unsigned refcnt;
/** Append on write. */
bool append;
/** Current position in the file. */
off_t pos;
} vfs_file_t;
extern link_t fs_head; /**< List of registered file systems. */
extern vfs_triplet_t rootfs; /**< Root node of the root file system. */
#define MAX_PATH_LEN (64 * 1024)
#define PLB_SIZE (2 * MAX_PATH_LEN)
/** Each instance of this type describes one path lookup in progress. */
typedef struct {
link_t plb_link; /**< Active PLB entries list link. */
unsigned index; /**< Index of the first character in PLB. */
size_t len; /**< Number of characters in this PLB entry. */
} plb_entry_t;
extern atomic_t plb_futex; /**< Futex protecting plb and plb_head. */
extern uint8_t *plb; /**< Path Lookup Buffer */
extern link_t plb_head; /**< List of active PLB entries. */
/** Holding this rwlock prevents changes in file system namespace. */
extern rwlock_t namespace_rwlock;
extern int vfs_grab_phone(int);
extern void vfs_release_phone(int);
extern int fs_name_to_handle(char *, bool);
extern int vfs_lookup_internal(char *, size_t, int, vfs_lookup_res_t *,
vfs_pair_t *);
extern bool vfs_nodes_init(void);
extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
extern void vfs_node_put(vfs_node_t *);
#define MAX_OPEN_FILES 128
extern bool vfs_files_init(void);
extern vfs_file_t *vfs_file_get(int);
extern int vfs_fd_alloc(void);
extern void vfs_fd_free(int);
extern void vfs_file_addref(vfs_file_t *);
extern void vfs_file_delref(vfs_file_t *);
extern void vfs_node_addref(vfs_node_t *);
extern void vfs_node_delref(vfs_node_t *);
extern void vfs_register(ipc_callid_t, ipc_call_t *);
extern void vfs_mount(ipc_callid_t, ipc_call_t *);
extern void vfs_open(ipc_callid_t, ipc_call_t *);
extern void vfs_read(ipc_callid_t, ipc_call_t *);
extern void vfs_write(ipc_callid_t, ipc_call_t *);
extern void vfs_seek(ipc_callid_t, ipc_call_t *);
extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
#endif
/**
* @}
*/