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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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2590 | jermar | 34 | * @file vfs_register.c |
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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2600 | jermar | 41 | #include <fibril.h> |
2520 | jermar | 42 | #include <errno.h> |
2532 | jermar | 43 | #include <stdio.h> |
2523 | jermar | 44 | #include <stdlib.h> |
2526 | jermar | 45 | #include <string.h> |
46 | #include <ctype.h> |
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2523 | jermar | 47 | #include <bool.h> |
2526 | jermar | 48 | #include <futex.h> |
2543 | jermar | 49 | #include <as.h> |
2526 | jermar | 50 | #include <libadt/list.h> |
2546 | jermar | 51 | #include <assert.h> |
2650 | jermar | 52 | #include <atomic.h> |
2520 | jermar | 53 | #include "vfs.h" |
54 | |||
2526 | jermar | 55 | atomic_t fs_head_futex = FUTEX_INITIALIZER; |
56 | link_t fs_head; |
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57 | |||
2546 | jermar | 58 | atomic_t fs_handle_next = { |
59 | .count = 1 |
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60 | }; |
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61 | |||
2523 | jermar | 62 | /** Verify the VFS info structure. |
63 | * |
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64 | * @param info Info structure to be verified. |
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65 | * |
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66 | * @return Non-zero if the info structure is sane, zero otherwise. |
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67 | */ |
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2526 | jermar | 68 | static bool vfs_info_sane(vfs_info_t *info) |
2521 | jermar | 69 | { |
2526 | jermar | 70 | int i; |
71 | |||
72 | /* |
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73 | * Check if the name is non-empty and is composed solely of ASCII |
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74 | * characters [a-z]+[a-z0-9_-]*. |
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75 | */ |
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2532 | jermar | 76 | if (!islower(info->name[0])) { |
77 | dprintf("The name doesn't start with a lowercase character.\n"); |
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2526 | jermar | 78 | return false; |
2532 | jermar | 79 | } |
2526 | jermar | 80 | for (i = 1; i < FS_NAME_MAXLEN; i++) { |
81 | if (!(islower(info->name[i]) || isdigit(info->name[i])) && |
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82 | (info->name[i] != '-') && (info->name[i] != '_')) { |
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2532 | jermar | 83 | if (info->name[i] == '\0') { |
2526 | jermar | 84 | break; |
2532 | jermar | 85 | } else { |
86 | dprintf("The name contains illegal " |
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87 | "characters.\n"); |
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2526 | jermar | 88 | return false; |
2532 | jermar | 89 | } |
2526 | jermar | 90 | } |
91 | } |
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2641 | jermar | 92 | /* |
93 | * This check is not redundant. It ensures that the name is |
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94 | * NULL-terminated, even if FS_NAME_MAXLEN characters are used. |
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95 | */ |
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96 | if (info->name[i] != '\0') { |
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97 | dprintf("The name is not properly NULL-terminated.\n"); |
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98 | return false; |
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99 | } |
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2526 | jermar | 100 | |
101 | |||
102 | /* |
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103 | * Check if the FS implements mandatory VFS operations. |
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104 | */ |
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2532 | jermar | 105 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] != VFS_OP_DEFINED) { |
106 | dprintf("Operation VFS_REGISTER not defined by the client.\n"); |
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2526 | jermar | 107 | return false; |
2532 | jermar | 108 | } |
109 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] != VFS_OP_DEFINED) { |
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110 | dprintf("Operation VFS_MOUNT not defined by the client.\n"); |
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2526 | jermar | 111 | return false; |
2532 | jermar | 112 | } |
113 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] != VFS_OP_DEFINED) { |
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114 | dprintf("Operation VFS_UNMOUNT not defined by the client.\n"); |
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2526 | jermar | 115 | return false; |
2532 | jermar | 116 | } |
117 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) { |
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118 | dprintf("Operation VFS_LOOKUP not defined by the client.\n"); |
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2527 | jermar | 119 | return false; |
2532 | jermar | 120 | } |
121 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] != VFS_OP_DEFINED) { |
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122 | dprintf("Operation VFS_OPEN not defined by the client.\n"); |
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2526 | jermar | 123 | return false; |
2532 | jermar | 124 | } |
125 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] != VFS_OP_DEFINED) { |
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126 | dprintf("Operation VFS_CLOSE not defined by the client.\n"); |
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2526 | jermar | 127 | return false; |
2532 | jermar | 128 | } |
129 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) { |
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130 | dprintf("Operation VFS_READ not defined by the client.\n"); |
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2526 | jermar | 131 | return false; |
2532 | jermar | 132 | } |
2526 | jermar | 133 | |
134 | /* |
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135 | * Check if each operation is either not defined, defined or default. |
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136 | */ |
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137 | for (i = VFS_FIRST; i < VFS_LAST; i++) { |
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2532 | jermar | 138 | if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) && |
139 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) && |
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140 | (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) { |
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141 | dprintf("Operation info not understood.\n"); |
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142 | return false; |
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143 | } |
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2526 | jermar | 144 | } |
145 | return true; |
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2523 | jermar | 146 | } |
147 | |||
148 | /** VFS_REGISTER protocol function. |
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149 | * |
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150 | * @param rid Hash of the call with the request. |
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151 | * @param request Call structure with the request. |
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152 | */ |
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2535 | jermar | 153 | void vfs_register(ipc_callid_t rid, ipc_call_t *request) |
2523 | jermar | 154 | { |
2521 | jermar | 155 | ipc_callid_t callid; |
156 | ipc_call_t call; |
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2523 | jermar | 157 | int rc; |
158 | size_t size; |
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2521 | jermar | 159 | |
2532 | jermar | 160 | dprintf("Processing VFS_REGISTER request received from %p.\n", |
2576 | jermar | 161 | request->in_phone_hash); |
2532 | jermar | 162 | |
2523 | jermar | 163 | /* |
164 | * The first call has to be IPC_M_DATA_SEND in which we receive the |
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165 | * VFS info structure from the client FS. |
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166 | */ |
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2676 | jermar | 167 | if (!ipc_data_write_receive(&callid, &size)) { |
2521 | jermar | 168 | /* |
169 | * The client doesn't obey the same protocol as we do. |
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2532 | jermar | 170 | */ |
171 | dprintf("Receiving of VFS info failed.\n"); |
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2619 | jermar | 172 | ipc_answer_0(callid, EINVAL); |
173 | ipc_answer_0(rid, EINVAL); |
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2521 | jermar | 174 | return; |
175 | } |
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2523 | jermar | 176 | |
2532 | jermar | 177 | dprintf("VFS info received, size = %d\n", size); |
178 | |||
2523 | jermar | 179 | /* |
2526 | jermar | 180 | * We know the size of the VFS info structure. See if the client |
181 | * understands this easy concept too. |
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2523 | jermar | 182 | */ |
183 | if (size != sizeof(vfs_info_t)) { |
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184 | /* |
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185 | * The client is sending us something, which cannot be |
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186 | * the info structure. |
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187 | */ |
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2532 | jermar | 188 | dprintf("Received VFS info has bad size.\n"); |
2619 | jermar | 189 | ipc_answer_0(callid, EINVAL); |
190 | ipc_answer_0(rid, EINVAL); |
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2523 | jermar | 191 | return; |
192 | } |
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193 | |||
194 | /* |
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2526 | jermar | 195 | * Allocate and initialize a buffer for the fs_info structure. |
2523 | jermar | 196 | */ |
2543 | jermar | 197 | fs_info_t *fs_info; |
2526 | jermar | 198 | fs_info = (fs_info_t *) malloc(sizeof(fs_info_t)); |
199 | if (!fs_info) { |
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2532 | jermar | 200 | dprintf("Could not allocate memory for FS info.\n"); |
2619 | jermar | 201 | ipc_answer_0(callid, ENOMEM); |
202 | ipc_answer_0(rid, ENOMEM); |
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2523 | jermar | 203 | return; |
204 | } |
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2526 | jermar | 205 | link_initialize(&fs_info->fs_link); |
2650 | jermar | 206 | futex_initialize(&fs_info->phone_futex, 1); |
2523 | jermar | 207 | |
2678 | jermar | 208 | rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size); |
2532 | jermar | 209 | if (rc != EOK) { |
210 | dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n", |
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211 | rc); |
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2526 | jermar | 212 | free(fs_info); |
2619 | jermar | 213 | ipc_answer_0(callid, rc); |
214 | ipc_answer_0(rid, rc); |
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2523 | jermar | 215 | return; |
216 | } |
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2532 | jermar | 217 | |
218 | dprintf("VFS info delivered.\n"); |
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2523 | jermar | 219 | |
2526 | jermar | 220 | if (!vfs_info_sane(&fs_info->vfs_info)) { |
221 | free(fs_info); |
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2619 | jermar | 222 | ipc_answer_0(callid, EINVAL); |
223 | ipc_answer_0(rid, EINVAL); |
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2523 | jermar | 224 | return; |
225 | } |
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226 | |||
2526 | jermar | 227 | futex_down(&fs_head_futex); |
228 | |||
229 | /* |
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230 | * Check for duplicit registrations. |
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231 | */ |
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2548 | jermar | 232 | if (fs_name_to_handle(fs_info->vfs_info.name, false)) { |
233 | /* |
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234 | * We already register a fs like this. |
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235 | */ |
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236 | dprintf("FS is already registered.\n"); |
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237 | futex_up(&fs_head_futex); |
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238 | free(fs_info); |
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2619 | jermar | 239 | ipc_answer_0(callid, EEXISTS); |
240 | ipc_answer_0(rid, EEXISTS); |
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2548 | jermar | 241 | return; |
2526 | jermar | 242 | } |
2527 | jermar | 243 | |
244 | /* |
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245 | * Add fs_info to the list of registered FS's. |
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246 | */ |
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2567 | jermar | 247 | dprintf("Inserting FS into the list of registered file systems.\n"); |
2527 | jermar | 248 | list_append(&fs_info->fs_link, &fs_head); |
249 | |||
250 | /* |
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251 | * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so |
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252 | * that a callback connection is created and we have a phone through |
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253 | * which to forward VFS requests to it. |
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2526 | jermar | 254 | */ |
2527 | jermar | 255 | callid = async_get_call(&call); |
256 | if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) { |
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2532 | jermar | 257 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
2527 | jermar | 258 | list_remove(&fs_info->fs_link); |
259 | futex_up(&fs_head_futex); |
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260 | free(fs_info); |
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2619 | jermar | 261 | ipc_answer_0(callid, EINVAL); |
262 | ipc_answer_0(rid, EINVAL); |
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2527 | jermar | 263 | return; |
264 | } |
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2637 | cejka | 265 | fs_info->phone = IPC_GET_ARG5(call); |
2619 | jermar | 266 | ipc_answer_0(callid, EOK); |
2526 | jermar | 267 | |
2532 | jermar | 268 | dprintf("Callback connection to FS created.\n"); |
269 | |||
2543 | jermar | 270 | /* |
271 | * The client will want us to send him the address space area with PLB. |
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272 | */ |
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2677 | jermar | 273 | |
274 | if (!ipc_share_in_receive(&callid, &size)) { |
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2543 | jermar | 275 | dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
276 | list_remove(&fs_info->fs_link); |
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277 | futex_up(&fs_head_futex); |
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278 | ipc_hangup(fs_info->phone); |
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279 | free(fs_info); |
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2619 | jermar | 280 | ipc_answer_0(callid, EINVAL); |
281 | ipc_answer_0(rid, EINVAL); |
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2543 | jermar | 282 | return; |
283 | } |
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284 | |||
285 | /* |
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286 | * We can only send the client address space area PLB_SIZE bytes long. |
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287 | */ |
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288 | if (size != PLB_SIZE) { |
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289 | dprintf("Client suggests wrong size of PFB, size = %d\n", size); |
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290 | list_remove(&fs_info->fs_link); |
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291 | futex_up(&fs_head_futex); |
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292 | ipc_hangup(fs_info->phone); |
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293 | free(fs_info); |
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2619 | jermar | 294 | ipc_answer_0(callid, EINVAL); |
295 | ipc_answer_0(rid, EINVAL); |
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2543 | jermar | 296 | return; |
297 | } |
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298 | |||
299 | /* |
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300 | * Commit to read-only sharing the PLB with the client. |
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301 | */ |
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2678 | jermar | 302 | (void) ipc_share_in_finalize(callid, plb, |
2677 | jermar | 303 | AS_AREA_READ | AS_AREA_CACHEABLE); |
2543 | jermar | 304 | |
305 | dprintf("Sharing PLB.\n"); |
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306 | |||
2527 | jermar | 307 | /* |
308 | * That was it. The FS has been registered. |
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2546 | jermar | 309 | * In reply to the VFS_REGISTER request, we assign the client file |
310 | * system a global file system handle. |
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2527 | jermar | 311 | */ |
2546 | jermar | 312 | fs_info->fs_handle = (int) atomic_postinc(&fs_handle_next); |
2619 | jermar | 313 | ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle); |
2548 | jermar | 314 | |
315 | futex_up(&fs_head_futex); |
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316 | |||
2576 | jermar | 317 | dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n", |
318 | FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle); |
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2521 | jermar | 319 | } |
320 | |||
2546 | jermar | 321 | /** For a given file system handle, implement policy for allocating a phone. |
322 | * |
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323 | * @param handle File system handle. |
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324 | * |
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325 | * @return Phone over which a multi-call request can be safely |
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326 | * sent. Return 0 if no phone was found. |
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327 | */ |
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328 | int vfs_grab_phone(int handle) |
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329 | { |
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330 | /* |
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331 | * For now, we don't try to be very clever and very fast. |
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332 | * We simply lookup the phone in the fs_head list. We currently don't |
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333 | * open any additional phones (even though that itself would be pretty |
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334 | * straightforward; housekeeping multiple open phones to a FS task would |
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335 | * be more demanding). Instead, we simply take the respective |
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336 | * phone_futex and keep it until vfs_release_phone(). |
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337 | */ |
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338 | futex_down(&fs_head_futex); |
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339 | link_t *cur; |
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340 | fs_info_t *fs; |
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341 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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342 | fs = list_get_instance(cur, fs_info_t, fs_link); |
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343 | if (fs->fs_handle == handle) { |
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344 | futex_up(&fs_head_futex); |
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345 | /* |
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346 | * For now, take the futex unconditionally. |
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347 | * Oh yeah, serialization rocks. |
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348 | * It will be up'ed in vfs_release_phone(). |
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349 | */ |
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350 | futex_down(&fs->phone_futex); |
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2600 | jermar | 351 | /* |
352 | * Avoid deadlock with other fibrils in the same thread |
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353 | * by disabling fibril preemption. |
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354 | */ |
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355 | fibril_inc_sercount(); |
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2546 | jermar | 356 | return fs->phone; |
357 | } |
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358 | } |
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359 | futex_up(&fs_head_futex); |
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360 | return 0; |
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361 | } |
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362 | |||
363 | /** Tell VFS that the phone is in use for any request. |
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364 | * |
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365 | * @param phone Phone to FS task. |
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366 | */ |
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367 | void vfs_release_phone(int phone) |
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368 | { |
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369 | bool found = false; |
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370 | |||
2600 | jermar | 371 | /* |
372 | * Undo the fibril_inc_sercount() done in vfs_grab_phone(). |
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373 | */ |
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374 | fibril_dec_sercount(); |
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375 | |||
2546 | jermar | 376 | futex_down(&fs_head_futex); |
377 | link_t *cur; |
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378 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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379 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
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380 | if (fs->phone == phone) { |
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381 | found = true; |
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382 | futex_up(&fs_head_futex); |
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383 | futex_up(&fs->phone_futex); |
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384 | return; |
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385 | } |
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386 | } |
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387 | futex_up(&fs_head_futex); |
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388 | |||
389 | /* |
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390 | * Not good to get here. |
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391 | */ |
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392 | assert(found == true); |
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393 | } |
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394 | |||
2548 | jermar | 395 | /** Convert file system name to its handle. |
396 | * |
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397 | * @param name File system name. |
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398 | * @param lock If true, the function will down and up the |
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399 | * fs_head_futex. |
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400 | * |
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401 | * @return File system handle or zero if file system not found. |
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402 | */ |
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403 | int fs_name_to_handle(char *name, bool lock) |
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404 | { |
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405 | int handle = 0; |
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406 | |||
407 | if (lock) |
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408 | futex_down(&fs_head_futex); |
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409 | link_t *cur; |
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410 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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411 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
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2641 | jermar | 412 | if (strncmp(fs->vfs_info.name, name, |
413 | sizeof(fs->vfs_info.name)) == 0) { |
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2548 | jermar | 414 | handle = fs->fs_handle; |
415 | break; |
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416 | } |
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417 | } |
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418 | if (lock) |
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419 | futex_up(&fs_head_futex); |
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420 | return handle; |
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421 | } |
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422 | |||
2518 | jermar | 423 | /** |
424 | * @} |
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425 | */ |