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2518 | 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 | /** |
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34 | * @file vfs.c |
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2535 | jermar | 35 | * @brief VFS_REGISTER method. |
2518 | jermar | 36 | */ |
37 | |||
2520 | jermar | 38 | #include <ipc/ipc.h> |
39 | #include <ipc/services.h> |
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40 | #include <async.h> |
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41 | #include <errno.h> |
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2532 | jermar | 42 | #include <stdio.h> |
2523 | jermar | 43 | #include <stdlib.h> |
2526 | jermar | 44 | #include <string.h> |
45 | #include <ctype.h> |
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2523 | jermar | 46 | #include <bool.h> |
2526 | jermar | 47 | #include <futex.h> |
2543 | jermar | 48 | #include <as.h> |
2526 | jermar | 49 | #include <libadt/list.h> |
2546 | jermar | 50 | #include <assert.h> |
2520 | jermar | 51 | #include "vfs.h" |
52 | |||
2526 | jermar | 53 | atomic_t fs_head_futex = FUTEX_INITIALIZER; |
54 | link_t fs_head; |
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55 | |||
2546 | jermar | 56 | atomic_t fs_handle_next = { |
57 | .count = 1 |
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58 | }; |
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59 | |||
2523 | jermar | 60 | /** Verify the VFS info structure. |
61 | * |
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62 | * @param info Info structure to be verified. |
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63 | * |
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64 | * @return Non-zero if the info structure is sane, zero otherwise. |
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65 | */ |
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2526 | jermar | 66 | static bool vfs_info_sane(vfs_info_t *info) |
2521 | jermar | 67 | { |
2526 | jermar | 68 | int i; |
69 | |||
70 | /* |
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71 | * Check if the name is non-empty and is composed solely of ASCII |
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72 | * characters [a-z]+[a-z0-9_-]*. |
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73 | */ |
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2532 | jermar | 74 | if (!islower(info->name[0])) { |
75 | dprintf("The name doesn't start with a lowercase character.\n"); |
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2526 | jermar | 76 | return false; |
2532 | jermar | 77 | } |
2526 | jermar | 78 | for (i = 1; i < FS_NAME_MAXLEN; i++) { |
79 | if (!(islower(info->name[i]) || isdigit(info->name[i])) && |
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80 | (info->name[i] != '-') && (info->name[i] != '_')) { |
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2532 | jermar | 81 | if (info->name[i] == '\0') { |
2526 | jermar | 82 | break; |
2532 | jermar | 83 | } else { |
84 | dprintf("The name contains illegal " |
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85 | "characters.\n"); |
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2526 | jermar | 86 | return false; |
2532 | jermar | 87 | } |
2526 | jermar | 88 | } |
89 | } |
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90 | |||
91 | |||
92 | /* |
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93 | * Check if the FS implements mandatory VFS operations. |
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94 | */ |
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2532 | jermar | 95 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] != VFS_OP_DEFINED) { |
96 | dprintf("Operation VFS_REGISTER not defined by the client.\n"); |
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2526 | jermar | 97 | return false; |
2532 | jermar | 98 | } |
99 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] != VFS_OP_DEFINED) { |
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100 | dprintf("Operation VFS_MOUNT not defined by the client.\n"); |
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2526 | jermar | 101 | return false; |
2532 | jermar | 102 | } |
103 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] != VFS_OP_DEFINED) { |
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104 | dprintf("Operation VFS_UNMOUNT not defined by the client.\n"); |
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2526 | jermar | 105 | return false; |
2532 | jermar | 106 | } |
107 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) { |
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108 | dprintf("Operation VFS_LOOKUP not defined by the client.\n"); |
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2527 | jermar | 109 | return false; |
2532 | jermar | 110 | } |
111 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] != VFS_OP_DEFINED) { |
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112 | dprintf("Operation VFS_OPEN not defined by the client.\n"); |
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2526 | jermar | 113 | return false; |
2532 | jermar | 114 | } |
115 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] != VFS_OP_DEFINED) { |
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116 | dprintf("Operation VFS_CLOSE not defined by the client.\n"); |
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2526 | jermar | 117 | return false; |
2532 | jermar | 118 | } |
119 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) { |
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120 | dprintf("Operation VFS_READ not defined by the client.\n"); |
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2526 | jermar | 121 | return false; |
2532 | jermar | 122 | } |
2526 | jermar | 123 | |
124 | /* |
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125 | * Check if each operation is either not defined, defined or default. |
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126 | */ |
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127 | for (i = VFS_FIRST; i < VFS_LAST; i++) { |
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2532 | jermar | 128 | if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) && |
129 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) && |
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130 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) { |
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131 | dprintf("Operation info not understood.\n"); |
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132 | return false; |
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133 | } |
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2526 | jermar | 134 | } |
135 | return true; |
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2523 | jermar | 136 | } |
137 | |||
138 | /** VFS_REGISTER protocol function. |
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139 | * |
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140 | * @param rid Hash of the call with the request. |
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141 | * @param request Call structure with the request. |
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142 | */ |
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2535 | jermar | 143 | void vfs_register(ipc_callid_t rid, ipc_call_t *request) |
2523 | jermar | 144 | { |
2521 | jermar | 145 | ipc_callid_t callid; |
146 | ipc_call_t call; |
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2523 | jermar | 147 | int rc; |
148 | size_t size; |
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2521 | jermar | 149 | |
2532 | jermar | 150 | dprintf("Processing VFS_REGISTER request received from %p.\n", |
2576 | jermar | 151 | request->in_phone_hash); |
2532 | jermar | 152 | |
2523 | jermar | 153 | /* |
154 | * The first call has to be IPC_M_DATA_SEND in which we receive the |
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155 | * VFS info structure from the client FS. |
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156 | */ |
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2531 | jermar | 157 | if (!ipc_data_receive(&callid, &call, NULL, &size)) { |
2521 | jermar | 158 | /* |
159 | * The client doesn't obey the same protocol as we do. |
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2532 | jermar | 160 | */ |
161 | dprintf("Receiving of VFS info failed.\n"); |
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2521 | jermar | 162 | ipc_answer_fast(callid, EINVAL, 0, 0); |
2523 | jermar | 163 | ipc_answer_fast(rid, EINVAL, 0, 0); |
2521 | jermar | 164 | return; |
165 | } |
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2523 | jermar | 166 | |
2532 | jermar | 167 | dprintf("VFS info received, size = %d\n", size); |
168 | |||
2523 | jermar | 169 | /* |
2526 | jermar | 170 | * We know the size of the VFS info structure. See if the client |
171 | * understands this easy concept too. |
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2523 | jermar | 172 | */ |
173 | if (size != sizeof(vfs_info_t)) { |
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174 | /* |
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175 | * The client is sending us something, which cannot be |
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176 | * the info structure. |
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177 | */ |
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2532 | jermar | 178 | dprintf("Received VFS info has bad size.\n"); |
2523 | jermar | 179 | ipc_answer_fast(callid, EINVAL, 0, 0); |
180 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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181 | return; |
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182 | } |
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183 | |||
184 | /* |
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2526 | jermar | 185 | * Allocate and initialize a buffer for the fs_info structure. |
2523 | jermar | 186 | */ |
2543 | jermar | 187 | fs_info_t *fs_info; |
2526 | jermar | 188 | fs_info = (fs_info_t *) malloc(sizeof(fs_info_t)); |
189 | if (!fs_info) { |
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2532 | jermar | 190 | dprintf("Could not allocate memory for FS info.\n"); |
2523 | jermar | 191 | ipc_answer_fast(callid, ENOMEM, 0, 0); |
192 | ipc_answer_fast(rid, ENOMEM, 0, 0); |
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193 | return; |
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194 | } |
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2526 | jermar | 195 | link_initialize(&fs_info->fs_link); |
2523 | jermar | 196 | |
2531 | jermar | 197 | rc = ipc_data_deliver(callid, &call, &fs_info->vfs_info, size); |
2532 | jermar | 198 | if (rc != EOK) { |
199 | dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n", |
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200 | rc); |
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2526 | jermar | 201 | free(fs_info); |
2523 | jermar | 202 | ipc_answer_fast(callid, rc, 0, 0); |
203 | ipc_answer_fast(rid, rc, 0, 0); |
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204 | return; |
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205 | } |
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2532 | jermar | 206 | |
207 | dprintf("VFS info delivered.\n"); |
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2523 | jermar | 208 | |
2526 | jermar | 209 | if (!vfs_info_sane(&fs_info->vfs_info)) { |
210 | free(fs_info); |
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2523 | jermar | 211 | ipc_answer_fast(callid, EINVAL, 0, 0); |
212 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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213 | return; |
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214 | } |
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215 | |||
2526 | jermar | 216 | futex_down(&fs_head_futex); |
217 | |||
218 | /* |
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219 | * Check for duplicit registrations. |
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220 | */ |
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2548 | jermar | 221 | if (fs_name_to_handle(fs_info->vfs_info.name, false)) { |
222 | /* |
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223 | * We already register a fs like this. |
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224 | */ |
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225 | dprintf("FS is already registered.\n"); |
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226 | futex_up(&fs_head_futex); |
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227 | free(fs_info); |
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228 | ipc_answer_fast(callid, EEXISTS, 0, 0); |
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229 | ipc_answer_fast(rid, EEXISTS, 0, 0); |
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230 | return; |
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2526 | jermar | 231 | } |
2527 | jermar | 232 | |
233 | /* |
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234 | * Add fs_info to the list of registered FS's. |
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235 | */ |
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2567 | jermar | 236 | dprintf("Inserting FS into the list of registered file systems.\n"); |
2527 | jermar | 237 | list_append(&fs_info->fs_link, &fs_head); |
238 | |||
239 | /* |
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240 | * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so |
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241 | * that a callback connection is created and we have a phone through |
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242 | * which to forward VFS requests to it. |
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2526 | jermar | 243 | */ |
2527 | jermar | 244 | callid = async_get_call(&call); |
245 | if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) { |
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2532 | jermar | 246 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
2527 | jermar | 247 | list_remove(&fs_info->fs_link); |
248 | futex_up(&fs_head_futex); |
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249 | free(fs_info); |
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250 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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251 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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252 | return; |
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253 | } |
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254 | fs_info->phone = IPC_GET_ARG3(call); |
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255 | ipc_answer_fast(callid, EOK, 0, 0); |
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2526 | jermar | 256 | |
2532 | jermar | 257 | dprintf("Callback connection to FS created.\n"); |
258 | |||
2543 | jermar | 259 | /* |
260 | * The client will want us to send him the address space area with PLB. |
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261 | */ |
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262 | callid = async_get_call(&call); |
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263 | if (IPC_GET_METHOD(call) != IPC_M_AS_AREA_RECV) { |
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264 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
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265 | list_remove(&fs_info->fs_link); |
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266 | futex_up(&fs_head_futex); |
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267 | ipc_hangup(fs_info->phone); |
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268 | free(fs_info); |
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269 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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270 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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271 | return; |
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272 | } |
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273 | |||
274 | /* |
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275 | * We can only send the client address space area PLB_SIZE bytes long. |
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276 | */ |
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277 | size = IPC_GET_ARG2(call); |
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278 | if (size != PLB_SIZE) { |
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279 | dprintf("Client suggests wrong size of PFB, size = %d\n", size); |
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280 | list_remove(&fs_info->fs_link); |
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281 | futex_up(&fs_head_futex); |
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282 | ipc_hangup(fs_info->phone); |
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283 | free(fs_info); |
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284 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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285 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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286 | return; |
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287 | } |
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288 | |||
289 | /* |
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290 | * Commit to read-only sharing the PLB with the client. |
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291 | */ |
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292 | ipc_answer_fast(callid, EOK, (ipcarg_t) plb, |
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293 | (ipcarg_t) (AS_AREA_READ | AS_AREA_CACHEABLE)); |
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294 | |||
295 | dprintf("Sharing PLB.\n"); |
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296 | |||
2527 | jermar | 297 | /* |
298 | * That was it. The FS has been registered. |
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2546 | jermar | 299 | * In reply to the VFS_REGISTER request, we assign the client file |
300 | * system a global file system handle. |
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2527 | jermar | 301 | */ |
2546 | jermar | 302 | fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next); |
303 | ipc_answer_fast(rid, EOK, (ipcarg_t) fs_info->fs_handle, 0); |
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2548 | jermar | 304 | |
305 | futex_up(&fs_head_futex); |
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306 | |||
2576 | jermar | 307 | dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n", |
308 | FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle); |
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2521 | jermar | 309 | } |
310 | |||
2546 | jermar | 311 | /** For a given file system handle, implement policy for allocating a phone. |
312 | * |
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313 | * @param handle File system handle. |
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314 | * |
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315 | * @return Phone over which a multi-call request can be safely |
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316 | * sent. Return 0 if no phone was found. |
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317 | */ |
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318 | int vfs_grab_phone(int handle) |
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319 | { |
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320 | /* |
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321 | * For now, we don't try to be very clever and very fast. |
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322 | * We simply lookup the phone in the fs_head list. We currently don't |
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323 | * open any additional phones (even though that itself would be pretty |
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324 | * straightforward; housekeeping multiple open phones to a FS task would |
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325 | * be more demanding). Instead, we simply take the respective |
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326 | * phone_futex and keep it until vfs_release_phone(). |
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327 | */ |
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328 | futex_down(&fs_head_futex); |
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329 | link_t *cur; |
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330 | fs_info_t *fs; |
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331 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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332 | fs = list_get_instance(cur, fs_info_t, fs_link); |
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333 | if (fs->fs_handle == handle) { |
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334 | futex_up(&fs_head_futex); |
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335 | /* |
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336 | * For now, take the futex unconditionally. |
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337 | * Oh yeah, serialization rocks. |
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338 | * It will be up'ed in vfs_release_phone(). |
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339 | */ |
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340 | futex_down(&fs->phone_futex); |
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341 | return fs->phone; |
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342 | } |
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343 | } |
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344 | futex_up(&fs_head_futex); |
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345 | return 0; |
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346 | } |
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347 | |||
348 | /** Tell VFS that the phone is in use for any request. |
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349 | * |
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350 | * @param phone Phone to FS task. |
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351 | */ |
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352 | void vfs_release_phone(int phone) |
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353 | { |
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354 | bool found = false; |
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355 | |||
356 | futex_down(&fs_head_futex); |
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357 | link_t *cur; |
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358 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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359 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
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360 | if (fs->phone == phone) { |
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361 | found = true; |
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362 | futex_up(&fs_head_futex); |
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363 | futex_up(&fs->phone_futex); |
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364 | return; |
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365 | } |
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366 | } |
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367 | futex_up(&fs_head_futex); |
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368 | |||
369 | /* |
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370 | * Not good to get here. |
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371 | */ |
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372 | assert(found == true); |
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373 | } |
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374 | |||
2548 | jermar | 375 | /** Convert file system name to its handle. |
376 | * |
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377 | * @param name File system name. |
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378 | * @param lock If true, the function will down and up the |
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379 | * fs_head_futex. |
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380 | * |
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381 | * @return File system handle or zero if file system not found. |
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382 | */ |
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383 | int fs_name_to_handle(char *name, bool lock) |
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384 | { |
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385 | int handle = 0; |
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386 | |||
387 | if (lock) |
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388 | futex_down(&fs_head_futex); |
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389 | link_t *cur; |
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390 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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391 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
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392 | if (strcmp(fs->vfs_info.name, name) == 0) { /* XXX: strncmp() */ |
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393 | handle = fs->fs_handle; |
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394 | break; |
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395 | } |
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396 | } |
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397 | if (lock) |
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398 | futex_up(&fs_head_futex); |
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399 | return handle; |
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400 | } |
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401 | |||
2518 | jermar | 402 | /** |
403 | * @} |
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404 | */ |