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| 2520 | jermar | 1 | /* |
| 2 | * Copyright (c) 2007 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup fs |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | |||
| 33 | #ifndef VFS_VFS_H_ |
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| 34 | #define VFS_VFS_H_ |
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| 35 | |||
| 2523 | jermar | 36 | #include <ipc/ipc.h> |
| 2529 | jermar | 37 | #include <libadt/list.h> |
| 2540 | jermar | 38 | #include <atomic.h> |
| 2680 | jermar | 39 | #include <rwlock.h> |
| 2542 | jermar | 40 | #include <sys/types.h> |
| 2550 | cejka | 41 | #include <bool.h> |
| 2523 | jermar | 42 | |
| 2535 | jermar | 43 | #define dprintf(...) printf(__VA_ARGS__) |
| 44 | |||
| 2550 | cejka | 45 | #define VFS_FIRST IPC_FIRST_USER_METHOD |
| 2523 | jermar | 46 | |
| 2526 | jermar | 47 | #define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST) |
| 48 | |||
| 2520 | jermar | 49 | typedef enum { |
| 2523 | jermar | 50 | VFS_REGISTER = VFS_FIRST, |
| 2520 | jermar | 51 | VFS_MOUNT, |
| 52 | VFS_UNMOUNT, |
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| 2527 | jermar | 53 | VFS_LOOKUP, |
| 2521 | jermar | 54 | VFS_OPEN, |
| 2523 | jermar | 55 | VFS_CREATE, |
| 56 | VFS_CLOSE, |
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| 57 | VFS_READ, |
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| 58 | VFS_WRITE, |
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| 59 | VFS_SEEK, |
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| 2593 | jermar | 60 | VFS_RENAME, |
| 61 | VFS_UNLINK, |
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| 2521 | jermar | 62 | VFS_LAST, /* keep this the last member of the enum */ |
| 2520 | jermar | 63 | } vfs_request_t; |
| 64 | |||
| 2521 | jermar | 65 | |
| 66 | /** |
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| 67 | * An instance of this structure is associated with a particular FS operation. |
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| 68 | * It tells VFS if the FS supports the operation or maybe if a default one |
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| 69 | * should be used. |
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| 70 | */ |
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| 71 | typedef enum { |
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| 2523 | jermar | 72 | VFS_OP_NULL = 0, |
| 2521 | jermar | 73 | VFS_OP_DEFAULT, |
| 74 | VFS_OP_DEFINED |
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| 75 | } vfs_op_t; |
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| 76 | |||
| 77 | #define FS_NAME_MAXLEN 20 |
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| 78 | |||
| 79 | /** |
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| 80 | * A structure like this is passed to VFS by each individual FS upon its |
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| 81 | * registration. It assosiates a human-readable identifier with each |
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| 82 | * registered FS. More importantly, through this structure, the FS announces |
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| 83 | * what operations it supports. |
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| 84 | */ |
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| 85 | typedef struct { |
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| 2523 | jermar | 86 | /** Unique identifier of the fs. */ |
| 2641 | jermar | 87 | char name[FS_NAME_MAXLEN + 1]; |
| 2523 | jermar | 88 | |
| 89 | /** Operations. */ |
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| 90 | vfs_op_t ops[VFS_LAST - VFS_FIRST]; |
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| 2521 | jermar | 91 | } vfs_info_t; |
| 92 | |||
| 2540 | jermar | 93 | /** |
| 94 | * A structure like this will be allocated for each registered file system. |
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| 95 | */ |
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| 2526 | jermar | 96 | typedef struct { |
| 97 | link_t fs_link; |
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| 98 | vfs_info_t vfs_info; |
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| 2546 | jermar | 99 | int fs_handle; |
| 100 | atomic_t phone_futex; /**< Phone serializing futex. */ |
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| 2527 | jermar | 101 | ipcarg_t phone; |
| 2526 | jermar | 102 | } fs_info_t; |
| 103 | |||
| 2540 | jermar | 104 | /** |
| 2587 | jermar | 105 | * VFS_PAIR uniquely represents a file system instance. |
| 106 | */ |
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| 107 | #define VFS_PAIR \ |
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| 108 | int fs_handle; \ |
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| 109 | int dev_handle; |
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| 110 | |||
| 111 | /** |
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| 112 | * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but |
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| 113 | * doesn't contain any state. For a stateful structure, see vfs_node_t. |
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| 2540 | jermar | 114 | * |
| 115 | * @note fs_handle, dev_handle and index are meant to be returned in one |
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| 116 | * IPC reply. |
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| 117 | */ |
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| 2587 | jermar | 118 | #define VFS_TRIPLET \ |
| 119 | VFS_PAIR; \ |
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| 120 | uint64_t index; |
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| 121 | |||
| 2540 | jermar | 122 | typedef struct { |
| 2587 | jermar | 123 | VFS_PAIR; |
| 124 | } vfs_pair_t; |
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| 125 | |||
| 126 | typedef struct { |
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| 127 | VFS_TRIPLET; |
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| 128 | } vfs_triplet_t; |
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| 129 | |||
| 130 | /** |
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| 131 | * Instances of this type represent an active, in-memory VFS node and any state |
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| 132 | * which may be associated with it. |
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| 133 | */ |
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| 134 | typedef struct { |
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| 135 | VFS_TRIPLET; /**< Identity of the node. */ |
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| 2593 | jermar | 136 | unsigned refcnt; /**< Usage counter. */ |
| 137 | link_t nh_link; /**< Node hash-table link. */ |
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| 2679 | jermar | 138 | |
| 2680 | jermar | 139 | /** Holding this rwlock prevents modifications of the node's contents. */ |
| 140 | atomic_t contents_rwlock; |
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| 2540 | jermar | 141 | } vfs_node_t; |
| 142 | |||
| 143 | /** |
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| 144 | * Instances of this type represent an open file. If the file is opened by more |
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| 145 | * than one task, there will be a separate structure allocated for each task. |
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| 146 | */ |
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| 147 | typedef struct { |
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| 148 | vfs_node_t *node; |
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| 149 | |||
| 150 | /** Number of file handles referencing this file. */ |
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| 2593 | jermar | 151 | unsigned refcnt; |
| 2540 | jermar | 152 | |
| 153 | /** Current position in the file. */ |
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| 154 | off_t pos; |
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| 155 | } vfs_file_t; |
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| 156 | |||
| 2542 | jermar | 157 | extern link_t fs_head; /**< List of registered file systems. */ |
| 2535 | jermar | 158 | |
| 2587 | jermar | 159 | extern vfs_triplet_t rootfs; /**< Root node of the root file system. */ |
| 2535 | jermar | 160 | |
| 2542 | jermar | 161 | #define MAX_PATH_LEN (64 * 1024) |
| 162 | |||
| 163 | #define PLB_SIZE (2 * MAX_PATH_LEN) |
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| 164 | |||
| 165 | /** Each instance of this type describes one path lookup in progress. */ |
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| 166 | typedef struct { |
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| 167 | link_t plb_link; /**< Active PLB entries list link. */ |
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| 168 | unsigned index; /**< Index of the first character in PLB. */ |
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| 169 | size_t len; /**< Number of characters in this PLB entry. */ |
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| 170 | } plb_entry_t; |
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| 171 | |||
| 172 | extern atomic_t plb_futex; /**< Futex protecting plb and plb_head. */ |
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| 173 | extern uint8_t *plb; /**< Path Lookup Buffer */ |
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| 174 | extern link_t plb_head; /**< List of active PLB entries. */ |
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| 175 | |||
| 2679 | jermar | 176 | /** Holding this futex prevents extern changes in file system namespace. */ |
| 177 | atomic_t namespace_futex; |
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| 2593 | jermar | 178 | |
| 2546 | jermar | 179 | extern int vfs_grab_phone(int); |
| 180 | extern void vfs_release_phone(int); |
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| 181 | |||
| 2552 | jermar | 182 | extern int fs_name_to_handle(char *, bool); |
| 2548 | jermar | 183 | |
| 2587 | jermar | 184 | extern int vfs_lookup_internal(char *, size_t, vfs_triplet_t *, vfs_pair_t *); |
| 2593 | jermar | 185 | |
| 2596 | jermar | 186 | extern bool vfs_nodes_init(void); |
| 2590 | jermar | 187 | extern vfs_node_t *vfs_node_get(vfs_triplet_t *); |
| 2593 | jermar | 188 | extern void vfs_node_put(vfs_node_t *); |
| 2544 | jermar | 189 | |
| 2596 | jermar | 190 | #define MAX_OPEN_FILES 128 |
| 191 | |||
| 2593 | jermar | 192 | extern bool vfs_files_init(void); |
| 193 | extern vfs_file_t *vfs_file_get(int); |
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| 194 | extern int vfs_fd_alloc(void); |
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| 195 | extern void vfs_fd_free(int); |
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| 196 | |||
| 197 | extern void vfs_file_addref(vfs_file_t *); |
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| 198 | extern void vfs_file_delref(vfs_file_t *); |
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| 199 | |||
| 200 | extern void vfs_node_addref(vfs_node_t *); |
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| 201 | extern void vfs_node_delref(vfs_node_t *); |
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| 202 | |||
| 2542 | jermar | 203 | extern void vfs_register(ipc_callid_t, ipc_call_t *); |
| 2544 | jermar | 204 | extern void vfs_mount(ipc_callid_t, ipc_call_t *); |
| 2560 | jermar | 205 | extern void vfs_open(ipc_callid_t, ipc_call_t *); |
| 2625 | jermar | 206 | extern void vfs_read(ipc_callid_t, ipc_call_t *); |
| 2666 | jermar | 207 | extern void vfs_write(ipc_callid_t, ipc_call_t *); |
| 2542 | jermar | 208 | |
| 2520 | jermar | 209 | #endif |
| 210 | |||
| 211 | /** |
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| 212 | * @} |
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| 2523 | jermar | 213 | */ |