| 1 | /*
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| 2 | * Copyright (c) 2008 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 |
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| 29 | /** @addtogroup fs
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| 30 | * @{
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| 31 | */
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| 32 |
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| 33 | #ifndef VFS_VFS_H_
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| 34 | #define VFS_VFS_H_
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| 35 |
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| 36 | #include <ipc/ipc.h>
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| 37 | #include <libadt/list.h>
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| 38 | #include <futex.h>
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| 39 | #include <rwlock.h>
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| 40 | #include <sys/types.h>
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| 41 | #include <bool.h>
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| 42 |
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| 43 | // FIXME: according to CONFIG_DEBUG
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| 44 | // #define dprintf(...) printf(__VA_ARGS__)
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| 45 |
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| 46 | #define dprintf(...)
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| 47 |
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| 48 | #define VFS_FIRST IPC_FIRST_USER_METHOD
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| 49 |
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| 50 | #define IPC_METHOD_TO_VFS_OP(m) ((m) - VFS_FIRST)
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| 51 |
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| 52 | /* Basic types. */
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| 53 | typedef int16_t fs_handle_t;
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| 54 | typedef int16_t dev_handle_t;
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| 55 | typedef uint32_t fs_index_t;
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| 56 |
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| 57 | typedef enum {
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| 58 | VFS_READ = VFS_FIRST,
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| 59 | VFS_WRITE,
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| 60 | VFS_TRUNCATE,
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| 61 | VFS_MOUNT,
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| 62 | VFS_UNMOUNT,
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| 63 | VFS_LAST_CMN, /* keep this the last member of this enum */
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| 64 | } vfs_request_cmn_t;
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| 65 |
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| 66 | typedef enum {
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| 67 | VFS_LOOKUP = VFS_LAST_CMN,
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| 68 | VFS_MOUNTED,
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| 69 | VFS_DESTROY,
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| 70 | VFS_LAST_CLNT, /* keep this the last member of this enum */
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| 71 | } vfs_request_clnt_t;
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| 72 |
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| 73 | typedef enum {
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| 74 | VFS_REGISTER = VFS_LAST_CMN,
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| 75 | VFS_OPEN,
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| 76 | VFS_CLOSE,
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| 77 | VFS_SEEK,
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| 78 | VFS_MKDIR,
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| 79 | VFS_UNLINK,
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| 80 | VFS_RENAME,
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| 81 | VFS_LAST_SRV, /* keep this the last member of this enum */
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| 82 | } vfs_request_srv_t;
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| 83 |
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| 84 |
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| 85 | /**
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| 86 | * An instance of this structure is associated with a particular FS operation.
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| 87 | * It tells VFS if the FS supports the operation or maybe if a default one
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| 88 | * should be used.
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| 89 | */
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| 90 | typedef enum {
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| 91 | VFS_OP_NULL = 0,
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| 92 | VFS_OP_DEFAULT,
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| 93 | VFS_OP_DEFINED
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| 94 | } vfs_op_t;
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| 95 |
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| 96 | #define FS_NAME_MAXLEN 20
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| 97 |
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| 98 | /**
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| 99 | * A structure like this is passed to VFS by each individual FS upon its
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| 100 | * registration. It assosiates a human-readable identifier with each
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| 101 | * registered FS. More importantly, through this structure, the FS announces
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| 102 | * what operations it supports.
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| 103 | */
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| 104 | typedef struct {
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| 105 | /** Unique identifier of the fs. */
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| 106 | char name[FS_NAME_MAXLEN + 1];
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| 107 |
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| 108 | /** Operations. */
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| 109 | vfs_op_t ops[VFS_LAST_CLNT - VFS_FIRST];
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| 110 | } vfs_info_t;
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| 111 |
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| 112 | /**
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| 113 | * A structure like this will be allocated for each registered file system.
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| 114 | */
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| 115 | typedef struct {
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| 116 | link_t fs_link;
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| 117 | vfs_info_t vfs_info;
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| 118 | fs_handle_t fs_handle;
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| 119 | futex_t phone_futex; /**< Phone serializing futex. */
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| 120 | ipcarg_t phone;
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| 121 | } fs_info_t;
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| 122 |
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| 123 | /**
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| 124 | * VFS_PAIR uniquely represents a file system instance.
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| 125 | */
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| 126 | #define VFS_PAIR \
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| 127 | fs_handle_t fs_handle; \
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| 128 | dev_handle_t dev_handle;
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| 129 |
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| 130 | /**
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| 131 | * VFS_TRIPLET uniquely identifies a file system node (e.g. directory, file) but
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| 132 | * doesn't contain any state. For a stateful structure, see vfs_node_t.
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| 133 | *
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| 134 | * @note fs_handle, dev_handle and index are meant to be returned in one
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| 135 | * IPC reply.
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| 136 | */
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| 137 | #define VFS_TRIPLET \
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| 138 | VFS_PAIR; \
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| 139 | fs_index_t index;
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| 140 |
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| 141 | typedef struct {
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| 142 | VFS_PAIR;
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| 143 | } vfs_pair_t;
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| 144 |
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| 145 | typedef struct {
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| 146 | VFS_TRIPLET;
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| 147 | } vfs_triplet_t;
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| 148 |
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| 149 | /*
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| 150 | * Lookup flags.
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| 151 | */
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| 152 | /**
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| 153 | * No lookup flags used.
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| 154 | */
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| 155 | #define L_NONE 0
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| 156 | /**
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| 157 | * Lookup will succeed only if the object is a regular file. If L_CREATE is
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| 158 | * specified, an empty file will be created. This flag is mutually exclusive
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| 159 | * with L_DIRECTORY.
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| 160 | */
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| 161 | #define L_FILE 1
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| 162 | /**
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| 163 | * Lookup wil succeed only if the object is a directory. If L_CREATE is
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| 164 | * specified, an empty directory will be created. This flag is mutually
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| 165 | * exclusive with L_FILE.
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| 166 | */
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| 167 | #define L_DIRECTORY 2
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| 168 | /**
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| 169 | * When used with L_CREATE, L_EXCLUSIVE will cause the lookup to fail if the
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| 170 | * object already exists. L_EXCLUSIVE is implied when L_DIRECTORY is used.
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| 171 | */
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| 172 | #define L_EXCLUSIVE 4
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| 173 | /**
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| 174 | * L_CREATE is used for creating both regular files and directories.
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| 175 | */
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| 176 | #define L_CREATE 8
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| 177 | /**
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| 178 | * L_LINK is used for linking to an already existing nodes.
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| 179 | */
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| 180 | #define L_LINK 16
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| 181 | /**
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| 182 | * L_UNLINK is used to remove leaves from the file system namespace. This flag
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| 183 | * cannot be passed directly by the client, but will be set by VFS during
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| 184 | * VFS_UNLINK.
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| 185 | */
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| 186 | #define L_UNLINK 32
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| 187 | /**
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| 188 | * L_PARENT performs a lookup but returns the triplet of the parent node.
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| 189 | * This flag may not be combined with any other lookup flag.
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| 190 | */
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| 191 | #define L_PARENT 64
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| 192 |
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| 193 | typedef enum vfs_node_type {
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| 194 | VFS_NODE_UNKNOWN,
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| 195 | VFS_NODE_FILE,
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| 196 | VFS_NODE_DIRECTORY,
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| 197 | } vfs_node_type_t;
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| 198 |
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| 199 | typedef struct {
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| 200 | vfs_triplet_t triplet;
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| 201 | vfs_node_type_t type;
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| 202 | size_t size;
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| 203 | unsigned lnkcnt;
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| 204 | } vfs_lookup_res_t;
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| 205 |
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| 206 | /**
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| 207 | * Instances of this type represent an active, in-memory VFS node and any state
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| 208 | * which may be associated with it.
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| 209 | */
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| 210 | typedef struct {
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| 211 | VFS_TRIPLET; /**< Identity of the node. */
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| 212 |
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| 213 | /**
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| 214 | * Usage counter. This includes, but is not limited to, all vfs_file_t
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| 215 | * structures that reference this node.
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| 216 | */
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| 217 | unsigned refcnt;
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| 218 |
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| 219 | /** Number of names this node has in the file system namespace. */
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| 220 | unsigned lnkcnt;
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| 221 |
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| 222 | link_t nh_link; /**< Node hash-table link. */
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| 223 |
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| 224 | vfs_node_type_t type; /**< Partial info about the node type. */
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| 225 |
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| 226 | size_t size; /**< Cached size if the node is a file. */
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| 227 |
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| 228 | /**
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| 229 | * Holding this rwlock prevents modifications of the node's contents.
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| 230 | */
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| 231 | rwlock_t contents_rwlock;
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| 232 | } vfs_node_t;
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| 233 |
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| 234 | /**
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| 235 | * Instances of this type represent an open file. If the file is opened by more
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| 236 | * than one task, there will be a separate structure allocated for each task.
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| 237 | */
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| 238 | typedef struct {
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| 239 | /** Serializes access to this open file. */
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| 240 | futex_t lock;
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| 241 |
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| 242 | vfs_node_t *node;
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| 243 |
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| 244 | /** Number of file handles referencing this file. */
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| 245 | unsigned refcnt;
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| 246 |
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| 247 | /** Append on write. */
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| 248 | bool append;
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| 249 |
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| 250 | /** Current position in the file. */
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| 251 | off_t pos;
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| 252 | } vfs_file_t;
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| 253 |
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| 254 | extern futex_t nodes_futex;
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| 255 |
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| 256 | extern link_t fs_head; /**< List of registered file systems. */
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| 257 |
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| 258 | extern vfs_pair_t rootfs; /**< Root file system. */
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| 259 |
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| 260 | #define MAX_PATH_LEN (64 * 1024)
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| 261 |
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| 262 | #define PLB_SIZE (2 * MAX_PATH_LEN)
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| 263 |
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| 264 | /** Each instance of this type describes one path lookup in progress. */
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| 265 | typedef struct {
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| 266 | link_t plb_link; /**< Active PLB entries list link. */
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| 267 | unsigned index; /**< Index of the first character in PLB. */
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| 268 | size_t len; /**< Number of characters in this PLB entry. */
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| 269 | } plb_entry_t;
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| 270 |
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| 271 | extern futex_t plb_futex; /**< Futex protecting plb and plb_head. */
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| 272 | extern uint8_t *plb; /**< Path Lookup Buffer */
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| 273 | extern link_t plb_head; /**< List of active PLB entries. */
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| 274 |
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| 275 | /** Holding this rwlock prevents changes in file system namespace. */
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| 276 | extern rwlock_t namespace_rwlock;
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| 277 |
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| 278 | extern int vfs_grab_phone(fs_handle_t);
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| 279 | extern void vfs_release_phone(int);
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| 280 |
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| 281 | extern fs_handle_t fs_name_to_handle(char *, bool);
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| 282 |
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| 283 | extern int vfs_lookup_internal(char *, int, vfs_lookup_res_t *, vfs_pair_t *,
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| 284 | ...);
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| 285 |
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| 286 | extern bool vfs_nodes_init(void);
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| 287 | extern vfs_node_t *vfs_node_get(vfs_lookup_res_t *);
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| 288 | extern void vfs_node_put(vfs_node_t *);
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| 289 |
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| 290 | #define MAX_OPEN_FILES 128
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| 291 |
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| 292 | extern bool vfs_files_init(void);
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| 293 | extern vfs_file_t *vfs_file_get(int);
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| 294 | extern int vfs_fd_alloc(void);
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| 295 | extern int vfs_fd_free(int);
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| 296 |
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| 297 | extern void vfs_file_addref(vfs_file_t *);
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| 298 | extern void vfs_file_delref(vfs_file_t *);
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| 299 |
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| 300 | extern void vfs_node_addref(vfs_node_t *);
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| 301 | extern void vfs_node_delref(vfs_node_t *);
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| 302 |
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| 303 | extern void vfs_register(ipc_callid_t, ipc_call_t *);
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| 304 | extern void vfs_mount(ipc_callid_t, ipc_call_t *);
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| 305 | extern void vfs_open(ipc_callid_t, ipc_call_t *);
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| 306 | extern void vfs_close(ipc_callid_t, ipc_call_t *);
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| 307 | extern void vfs_read(ipc_callid_t, ipc_call_t *);
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| 308 | extern void vfs_write(ipc_callid_t, ipc_call_t *);
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| 309 | extern void vfs_seek(ipc_callid_t, ipc_call_t *);
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| 310 | extern void vfs_truncate(ipc_callid_t, ipc_call_t *);
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| 311 | extern void vfs_mkdir(ipc_callid_t, ipc_call_t *);
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| 312 | extern void vfs_unlink(ipc_callid_t, ipc_call_t *);
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| 313 | extern void vfs_rename(ipc_callid_t, ipc_call_t *);
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| 314 |
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| 315 | #endif
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| 316 |
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| 317 | /**
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| 318 | * @}
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| 319 | */
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