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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> |
2529 | jermar | 45 | #include "../../vfs/vfs.h" |
2006 | decky | 46 | |
2532 | jermar | 47 | #define dprintf(...) printf(__VA_ARGS__) |
48 | |||
2529 | jermar | 49 | vfs_info_t fat_vfs_info = { |
50 | .name = "fat", |
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51 | .ops = { |
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52 | [IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] = VFS_OP_DEFINED, |
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53 | [IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] = VFS_OP_DEFINED, |
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54 | [IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] = VFS_OP_DEFINED, |
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55 | [IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] = VFS_OP_DEFINED, |
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56 | [IPC_METHOD_TO_VFS_OP(VFS_OPEN)] = VFS_OP_DEFINED, |
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57 | [IPC_METHOD_TO_VFS_OP(VFS_CREATE)] = VFS_OP_DEFINED, |
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58 | [IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] = VFS_OP_DEFINED, |
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59 | [IPC_METHOD_TO_VFS_OP(VFS_READ)] = VFS_OP_DEFINED, |
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60 | [IPC_METHOD_TO_VFS_OP(VFS_WRITE)] = VFS_OP_NULL, |
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61 | [IPC_METHOD_TO_VFS_OP(VFS_SEEK)] = VFS_OP_DEFAULT |
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62 | } |
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63 | }; |
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64 | |||
2536 | jermar | 65 | /** |
66 | * This connection fibril processes VFS requests from VFS. |
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67 | * |
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68 | * In order to support simultaneous VFS requests, our design is as follows. |
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69 | * The connection fibril accepts VFS requests from VFS. If there is only one |
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70 | * instance of the fibril, VFS will need to serialize all VFS requests it sends |
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71 | * to FAT. To overcome this bottleneck, VFS can send FAT the IPC_M_CONNECT_ME_TO |
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72 | * call. In that case, a new connection fibril will be created, which in turn |
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73 | * will accept the call. Thus, a new phone will be opened for VFS. |
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74 | * |
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75 | * There are few issues with this arrangement. First, VFS can run out of |
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76 | * available phones. In that case, VFS can close some other phones or use one |
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77 | * phone for more serialized requests. Similarly, FAT can refuse to duplicate |
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78 | * the connection. VFS should then just make use of already existing phones and |
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79 | * route its requests through them. To avoid paying the fibril creation price |
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80 | * upon each request, FAT might want to keep the connections open after the |
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81 | * request has been completed. |
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2531 | jermar | 82 | */ |
2536 | jermar | 83 | static void fat_connection(ipc_callid_t iid, ipc_call_t *icall) |
2531 | jermar | 84 | { |
2536 | jermar | 85 | if (iid) { |
86 | /* |
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87 | * This only happens for connections opened by |
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88 | * IPC_M_CONNECT_ME_TO calls as opposed to callback connections |
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89 | * created by IPC_M_CONNECT_TO_ME. |
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90 | */ |
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91 | ipc_answer_fast(iid, EOK, 0, 0); |
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92 | } |
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93 | |||
94 | dprintf("VFS-FAT connection established.\n"); |
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2531 | jermar | 95 | while (1) { |
96 | ipc_callid_t callid; |
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97 | ipc_call_t call; |
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98 | |||
99 | callid = async_get_call(&call); |
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2536 | jermar | 100 | switch (IPC_GET_METHOD(call)) { |
101 | default: |
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102 | ipc_answer_fast(callid, ENOTSUP, 0, 0); |
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103 | break; |
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104 | } |
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2531 | jermar | 105 | } |
106 | } |
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107 | |||
2006 | decky | 108 | int main(int argc, char **argv) |
109 | { |
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2532 | jermar | 110 | int vfs_phone; |
2529 | jermar | 111 | |
2532 | jermar | 112 | printf("FAT: HelenOS FAT file system server.\n"); |
113 | |||
2529 | jermar | 114 | vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0); |
2532 | jermar | 115 | while (vfs_phone < EOK) { |
2529 | jermar | 116 | usleep(10000); |
117 | vfs_phone = ipc_connect_me_to(PHONE_NS, SERVICE_VFS, 0); |
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118 | } |
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119 | |||
2531 | jermar | 120 | /* |
121 | * Tell VFS that we are here and want to get registered. |
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122 | * We use the async framework because VFS will answer the request |
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123 | * out-of-order, when it knows that the operation succeeded or failed. |
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124 | */ |
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125 | ipc_call_t answer; |
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126 | aid_t req = async_send_2(vfs_phone, VFS_REGISTER, 0, 0, &answer); |
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2529 | jermar | 127 | |
2531 | jermar | 128 | /* |
129 | * Send our VFS info structure to VFS. |
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130 | */ |
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131 | int rc = ipc_data_send(vfs_phone, &fat_vfs_info, sizeof(fat_vfs_info)); |
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132 | if (rc != EOK) { |
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133 | async_wait_for(req, NULL); |
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134 | return rc; |
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135 | } |
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136 | |||
137 | /* |
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138 | * Ask VFS for callback connection. |
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139 | */ |
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140 | ipcarg_t phonehash; |
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141 | ipc_connect_to_me(vfs_phone, 0, 0, &phonehash); |
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142 | |||
2536 | jermar | 143 | /* |
144 | * Create a connection fibril to handle the callback connection. |
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145 | */ |
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2531 | jermar | 146 | async_new_connection(phonehash, 0, NULL, fat_connection); |
2536 | jermar | 147 | |
148 | /* |
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149 | * Tell the async framework that other connections are to be handled by |
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150 | * the same connection fibril as well. |
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151 | */ |
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152 | async_set_client_connection(fat_connection); |
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2532 | jermar | 153 | |
154 | /* |
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155 | * Pick up the answer for the request to the VFS_REQUEST call. |
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156 | */ |
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157 | async_wait_for(req, NULL); |
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158 | dprintf("FAT filesystem registered.\n"); |
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2533 | jermar | 159 | |
2536 | jermar | 160 | async_create_manager(); |
161 | |||
2533 | jermar | 162 | /* |
2534 | jermar | 163 | * TODO: Interestingly, if we merely return, the only thread dies. |
2536 | jermar | 164 | * If the only thread dies, the whole task is destroyed. |
165 | * Prevent the thread from exiting when there are active fibrils. |
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2533 | jermar | 166 | */ |
2534 | jermar | 167 | fibril_schedule_next_adv(FIBRIL_FROM_DEAD); |
168 | /* not reached */ |
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169 | |||
2006 | decky | 170 | return 0; |
171 | } |
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172 | |||
173 | /** |
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174 | * @} |
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175 | */ |