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2006 | decky | 1 | /* |
2071 | jermar | 2 | * Copyright (c) 2006 Martin Decky |
2529 | jermar | 3 | * Copyright (c) 2007 Jakub Jermar |
2006 | decky | 4 | * All rights reserved. |
5 | * |
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6 | * Redistribution and use in source and binary forms, with or without |
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7 | * modification, are permitted provided that the following conditions |
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8 | * are met: |
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9 | * |
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10 | * - Redistributions of source code must retain the above copyright |
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11 | * notice, this list of conditions and the following disclaimer. |
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12 | * - Redistributions in binary form must reproduce the above copyright |
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13 | * notice, this list of conditions and the following disclaimer in the |
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14 | * documentation and/or other materials provided with the distribution. |
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15 | * - The name of the author may not be used to endorse or promote products |
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16 | * derived from this software without specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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19 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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20 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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21 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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22 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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23 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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24 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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25 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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28 | */ |
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29 | |||
30 | /** @addtogroup fs |
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31 | * @{ |
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32 | */ |
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33 | |||
34 | /** |
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2529 | jermar | 35 | * @file fat.c |
36 | * @brief FAT file system driver for HelenOS. |
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2006 | decky | 37 | */ |
38 | |||
2529 | jermar | 39 | #include <ipc/ipc.h> |
40 | #include <ipc/services.h> |
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2531 | jermar | 41 | #include <async.h> |
2529 | jermar | 42 | #include <errno.h> |
43 | #include <unistd.h> |
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2536 | jermar | 44 | #include <stdio.h> |
2543 | jermar | 45 | #include <as.h>> |
2529 | jermar | 46 | #include "../../vfs/vfs.h" |
2006 | decky | 47 | |
2532 | jermar | 48 | #define dprintf(...) printf(__VA_ARGS__) |
49 | |||
2529 | jermar | 50 | vfs_info_t fat_vfs_info = { |
51 | .name = "fat", |
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52 | .ops = { |
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53 | [IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] = VFS_OP_DEFINED, |
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54 | [IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_DEFINED, |
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55 | [IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_DEFINED, |
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56 | [IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED, |
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57 | [IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED, |
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58 | [IPC_METHOD_TO_VFS_OP(VFS_CREATE)] = VFS_OP_DEFINED, |
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59 | [IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED, |
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60 | [IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED, |
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61 | [IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL, |
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62 | [IPC_METHOD_TO_VFS_OP(VFS_SEEK)] = VFS_OP_DEFAULT |
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63 | } |
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64 | }; |
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65 | |||
2543 | jermar | 66 | uint8_t *plb_ro = NULL; |
67 | |||
2536 | jermar | 68 | /** |
69 | * This connection fibril processes VFS requests from VFS. |
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70 | * |
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71 | * In order to support simultaneous VFS requests, our design is as follows. |
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72 | * The connection fibril accepts VFS requests from VFS. If there is only one |
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73 | * instance of the fibril, VFS will need to serialize all VFS requests it sends |
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74 | * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO |
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75 | * call. In that case, a new connection fibril will be created, which in turn |
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76 | * will accept the call. Thus, a new phone will be opened for VFS. |
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77 | * |
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78 | * There are few issues with this arrangement. First, VFS can run out of |
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79 | * available phones. In that case, VFS can close some other phones or use one |
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80 | * phone for more serialized requests. Similarly, FAT can refuse to duplicate |
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81 | * the connection. VFS should then just make use of already existing phones and |
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82 | * route its requests through them. To avoid paying the fibril creation price |
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83 | * upon each request, FAT might want to keep the connections open after the |
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84 | * request has been completed. |
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2531 | jermar | 85 | */ |
2536 | jermar | 86 | static void fat_connection(ipc_callid_t iid, ipc_call_t *icall) |
2531 | jermar | 87 | { |
2536 | jermar | 88 | if (iid) { |
89 | /* |
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90 | * This only happens for connections opened by |
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91 | * IPC_M_CONNECT_ME_TO calls as opposed to callback connections |
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92 | * created by IPC_M_CONNECT_TO_ME. |
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93 | */ |
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94 | ipc_answer_fast(iid, EOK, 0, 0); |
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95 | } |
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96 | |||
97 | dprintf("VFS-FAT connection established.\n"); |
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2531 | jermar | 98 | while (1) { |
99 | ipc_callid_t callid; |
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100 | ipc_call_t call; |
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101 | |||
102 | callid = async_get_call(&call); |
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2536 | jermar | 103 | switch (IPC_GET_METHOD(call)) { |
104 | default: |
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105 | ipc_answer_fast(callid, ENOTSUP, 0, 0); |
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106 | break; |
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107 | } |
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2531 | jermar | 108 | } |
109 | } |
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110 | |||
2006 | decky | 111 | int main(int argc, char **argv) |
112 | { |
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2532 | jermar | 113 | int vfs_phone; |
2529 | jermar | 114 | |
2532 | jermar | 115 | printf("FAT: HelenOS FAT file system server.\n"); |
116 | |||
2529 | jermar | 117 | vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0); |
2532 | jermar | 118 | while (vfs_phone < EOK) { |
2529 | jermar | 119 | usleep(10000); |
120 | vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0); |
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121 | } |
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122 | |||
2531 | jermar | 123 | /* |
124 | * Tell VFS that we are here and want to get registered. |
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125 | * We use the async framework because VFS will answer the request |
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126 | * out-of-order, when it knows that the operation succeeded or failed. |
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127 | */ |
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128 | ipc_call_t answer; |
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129 | aid_t req = async_send_2(vfs_phone, VFS_REGISTER, 0, 0, &answer); |
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2529 | jermar | 130 | |
2531 | jermar | 131 | /* |
132 | * Send our VFS info structure to VFS. |
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133 | */ |
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134 | int rc = ipc_data_send(vfs_phone, &fat_vfs_info, sizeof(fat_vfs_info)); |
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135 | if (rc != EOK) { |
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136 | async_wait_for(req, NULL); |
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137 | return rc; |
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138 | } |
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139 | |||
140 | /* |
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141 | * Ask VFS for callback connection. |
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142 | */ |
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143 | ipcarg_t phonehash; |
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144 | ipc_connect_to_me(vfs_phone, 0, 0, &phonehash); |
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145 | |||
2536 | jermar | 146 | /* |
2543 | jermar | 147 | * Allocate piece of address space for PLB. |
148 | */ |
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149 | plb_ro = as_get_mappable_page(PLB_SIZE); |
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150 | if (!plb_ro) { |
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151 | async_wait_for(req, NULL); |
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152 | return ENOMEM; |
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153 | } |
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154 | |||
155 | /* |
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156 | * Request sharing the Path Lookup Buffer with VFS. |
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157 | */ |
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158 | rc = ipc_call_sync_3(vfs_phone, IPC_M_AS_AREA_RECV, plb_ro, PLB_SIZE, 0, |
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159 | NULL, NULL, NULL); |
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160 | if (rc) { |
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161 | async_wait_for(req, NULL); |
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162 | return rc; |
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163 | } |
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164 | |||
165 | /* |
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2536 | jermar | 166 | * Create a connection fibril to handle the callback connection. |
167 | */ |
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2531 | jermar | 168 | async_new_connection(phonehash, 0, NULL, fat_connection); |
2536 | jermar | 169 | |
170 | /* |
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171 | * Tell the async framework that other connections are to be handled by |
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172 | * the same connection fibril as well. |
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173 | */ |
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174 | async_set_client_connection(fat_connection); |
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2532 | jermar | 175 | |
176 | /* |
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177 | * Pick up the answer for the request to the VFS_REQUEST call. |
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178 | */ |
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179 | async_wait_for(req, NULL); |
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180 | dprintf("FAT filesystem registered.\n"); |
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2533 | jermar | 181 | |
2536 | jermar | 182 | async_create_manager(); |
183 | |||
2533 | jermar | 184 | /* |
2534 | jermar | 185 | * TODO: Interestingly, if we merely return, the only thread dies. |
2536 | jermar | 186 | * If the only thread dies, the whole task is destroyed. |
187 | * Prevent the thread from exiting when there are active fibrils. |
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2533 | jermar | 188 | */ |
2534 | jermar | 189 | fibril_schedule_next_adv(FIBRIL_FROM_DEAD); |
190 | /* not reached */ |
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191 | |||
2006 | decky | 192 | return 0; |
193 | } |
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194 | |||
195 | /** |
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196 | * @} |
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197 | */ |