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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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35 | * @brief VFS multiplexer for HelenOS. |
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36 | */ |
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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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2523 | jermar | 42 | #include <stdlib.h> |
2526 | jermar | 43 | #include <string.h> |
44 | #include <ctype.h> |
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2523 | jermar | 45 | #include <bool.h> |
2526 | jermar | 46 | #include <futex.h> |
47 | #include <libadt/list.h> |
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2520 | jermar | 48 | #include "vfs.h" |
49 | |||
2526 | jermar | 50 | atomic_t fs_head_futex = FUTEX_INITIALIZER; |
51 | link_t fs_head; |
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52 | |||
2523 | jermar | 53 | /** Verify the VFS info structure. |
54 | * |
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55 | * @param info Info structure to be verified. |
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56 | * |
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57 | * @return Non-zero if the info structure is sane, zero otherwise. |
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58 | */ |
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2526 | jermar | 59 | static bool vfs_info_sane(vfs_info_t *info) |
2521 | jermar | 60 | { |
2526 | jermar | 61 | int i; |
62 | |||
63 | /* |
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64 | * Check if the name is non-empty and is composed solely of ASCII |
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65 | * characters [a-z]+[a-z0-9_-]*. |
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66 | */ |
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67 | if (!islower(info->name[0])) |
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68 | return false; |
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69 | for (i = 1; i < FS_NAME_MAXLEN; i++) { |
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70 | if (!(islower(info->name[i]) || isdigit(info->name[i])) && |
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71 | (info->name[i] != '-') && (info->name[i] != '_')) { |
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72 | if (info->name[i] == '\0') |
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73 | break; |
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74 | else |
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75 | return false; |
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76 | } |
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77 | } |
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78 | |||
79 | |||
80 | /* |
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81 | * Check if the FS implements mandatory VFS operations. |
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82 | */ |
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83 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_REGISTER)] != VFS_OP_DEFINED) |
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84 | return false; |
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85 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_MOUNT)] != VFS_OP_DEFINED) |
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86 | return false; |
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87 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_UNMOUNT)] != VFS_OP_DEFINED) |
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88 | return false; |
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2527 | jermar | 89 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) |
90 | return false; |
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2526 | jermar | 91 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_OPEN)] != VFS_OP_DEFINED) |
92 | return false; |
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93 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_CLOSE)] != VFS_OP_DEFINED) |
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94 | return false; |
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95 | if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) |
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96 | return false; |
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97 | |||
98 | /* |
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99 | * Check if each operation is either not defined, defined or default. |
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100 | */ |
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101 | for (i = VFS_FIRST; i < VFS_LAST; i++) { |
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102 | if ((IPC_METHOD_TO_VFS_OP(i) != VFS_OP_NULL) && |
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103 | (IPC_METHOD_TO_VFS_OP(i) != VFS_OP_DEFAULT) && |
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104 | (IPC_METHOD_TO_VFS_OP(i) != VFS_OP_DEFINED)) |
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105 | return false; |
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106 | } |
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107 | return true; |
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2523 | jermar | 108 | } |
109 | |||
110 | /** VFS_REGISTER protocol function. |
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111 | * |
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112 | * @param rid Hash of the call with the request. |
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113 | * @param request Call structure with the request. |
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114 | */ |
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115 | static void vfs_register(ipc_callid_t rid, ipc_call_t *request) |
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116 | { |
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2521 | jermar | 117 | ipc_callid_t callid; |
118 | ipc_call_t call; |
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2523 | jermar | 119 | int rc; |
120 | size_t size; |
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2521 | jermar | 121 | |
2523 | jermar | 122 | /* |
123 | * The first call has to be IPC_M_DATA_SEND in which we receive the |
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124 | * VFS info structure from the client FS. |
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125 | */ |
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126 | if (!ipc_data_send_accept(&callid, &call, NULL, &size)) { |
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2521 | jermar | 127 | /* |
128 | * The client doesn't obey the same protocol as we do. |
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129 | */ |
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130 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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2523 | jermar | 131 | ipc_answer_fast(rid, EINVAL, 0, 0); |
2521 | jermar | 132 | return; |
133 | } |
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2523 | jermar | 134 | |
135 | /* |
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2526 | jermar | 136 | * We know the size of the VFS info structure. See if the client |
137 | * understands this easy concept too. |
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2523 | jermar | 138 | */ |
139 | if (size != sizeof(vfs_info_t)) { |
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140 | /* |
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141 | * The client is sending us something, which cannot be |
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142 | * the info structure. |
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143 | */ |
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144 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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145 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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146 | return; |
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147 | } |
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2526 | jermar | 148 | fs_info_t *fs_info; |
2523 | jermar | 149 | |
150 | /* |
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2526 | jermar | 151 | * Allocate and initialize a buffer for the fs_info structure. |
2523 | jermar | 152 | */ |
2526 | jermar | 153 | fs_info = (fs_info_t *) malloc(sizeof(fs_info_t)); |
154 | if (!fs_info) { |
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2523 | jermar | 155 | ipc_answer_fast(callid, ENOMEM, 0, 0); |
156 | ipc_answer_fast(rid, ENOMEM, 0, 0); |
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157 | return; |
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158 | } |
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2526 | jermar | 159 | link_initialize(&fs_info->fs_link); |
2523 | jermar | 160 | |
2526 | jermar | 161 | rc = ipc_data_send_answer(callid, &call, &fs_info->vfs_info, size); |
2523 | jermar | 162 | if (!rc) { |
2526 | jermar | 163 | free(fs_info); |
2523 | jermar | 164 | ipc_answer_fast(callid, rc, 0, 0); |
165 | ipc_answer_fast(rid, rc, 0, 0); |
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166 | return; |
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167 | } |
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168 | |||
2526 | jermar | 169 | if (!vfs_info_sane(&fs_info->vfs_info)) { |
170 | free(fs_info); |
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2523 | jermar | 171 | ipc_answer_fast(callid, EINVAL, 0, 0); |
172 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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173 | return; |
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174 | } |
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175 | |||
2526 | jermar | 176 | futex_down(&fs_head_futex); |
177 | |||
178 | /* |
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179 | * Check for duplicit registrations. |
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180 | */ |
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181 | link_t *cur; |
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182 | for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
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183 | fs_info_t *fi = list_get_instance(cur, fs_info_t, |
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184 | fs_link); |
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185 | /* TODO: replace strcmp with strncmp once we have it */ |
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186 | if (strcmp(fs_info->vfs_info.name, fi->vfs_info.name) == 0) { |
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187 | /* |
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188 | * We already register a fs like this. |
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189 | */ |
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190 | futex_up(&fs_head_futex); |
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191 | free(fs_info); |
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192 | ipc_answer_fast(callid, EEXISTS, 0, 0); |
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193 | ipc_answer_fast(rid, EEXISTS, 0, 0); |
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194 | return; |
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195 | } |
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196 | } |
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2527 | jermar | 197 | |
198 | /* |
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199 | * Add fs_info to the list of registered FS's. |
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200 | */ |
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201 | list_append(&fs_info->fs_link, &fs_head); |
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202 | |||
203 | /* |
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204 | * ACK receiving a properly formatted, non-duplicit vfs_info. |
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205 | */ |
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206 | ipc_answer_fast(callid, EOK, 0, 0); |
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2526 | jermar | 207 | |
208 | /* |
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2527 | jermar | 209 | * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so |
210 | * that a callback connection is created and we have a phone through |
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211 | * which to forward VFS requests to it. |
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2526 | jermar | 212 | */ |
2527 | jermar | 213 | callid = async_get_call(&call); |
214 | if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) { |
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215 | list_remove(&fs_info->fs_link); |
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216 | futex_up(&fs_head_futex); |
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217 | free(fs_info); |
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218 | ipc_answer_fast(callid, EINVAL, 0, 0); |
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219 | ipc_answer_fast(rid, EINVAL, 0, 0); |
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220 | return; |
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221 | } |
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222 | fs_info->phone = IPC_GET_ARG3(call); |
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223 | ipc_answer_fast(callid, EOK, 0, 0); |
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2526 | jermar | 224 | |
225 | futex_up(&fs_head_futex); |
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2527 | jermar | 226 | |
227 | /* |
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228 | * That was it. The FS has been registered. |
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229 | */ |
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230 | ipc_answer_fast(rid, EOK, 0, 0); |
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2521 | jermar | 231 | } |
232 | |||
2520 | jermar | 233 | static void vfs_connection(ipc_callid_t iid, ipc_call_t *icall) |
234 | { |
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2523 | jermar | 235 | bool keep_on_going = 1; |
2520 | jermar | 236 | |
237 | /* |
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238 | * The connection was opened via the IPC_CONNECT_ME_TO call. |
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239 | * This call needs to be answered. |
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240 | */ |
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2523 | jermar | 241 | ipc_answer_fast(iid, EOK, 0, 0); |
2520 | jermar | 242 | |
243 | /* |
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2523 | jermar | 244 | * Here we enter the main connection fibril loop. |
245 | * The logic behind this loop and the protocol is that we'd like to keep |
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246 | * each connection open for a while before we close it. The benefit of |
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247 | * this is that the client doesn't have to establish a new connection |
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248 | * upon each request. On the other hand, the client must be ready to |
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249 | * re-establish a connection if we hang it up due to reaching of maximum |
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250 | * number of requests per connection or due to the client timing out. |
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2520 | jermar | 251 | */ |
2523 | jermar | 252 | |
253 | while (keep_on_going) { |
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254 | ipc_callid_t callid; |
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255 | ipc_call_t call; |
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256 | |||
257 | callid = async_get_call(&call); |
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258 | |||
259 | switch (IPC_GET_METHOD(call)) { |
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260 | case IPC_M_PHONE_HUNGUP: |
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261 | keep_on_going = false; |
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262 | break; |
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263 | case VFS_REGISTER: |
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264 | vfs_register(callid, &call); |
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265 | keep_on_going = false; |
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266 | break; |
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267 | case VFS_MOUNT: |
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268 | case VFS_UNMOUNT: |
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269 | case VFS_OPEN: |
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270 | case VFS_CREATE: |
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271 | case VFS_CLOSE: |
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272 | case VFS_READ: |
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273 | case VFS_WRITE: |
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274 | case VFS_SEEK: |
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275 | default: |
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276 | ipc_answer_fast(callid, ENOTSUP, 0, 0); |
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277 | break; |
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278 | } |
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2520 | jermar | 279 | } |
2523 | jermar | 280 | |
281 | /* TODO: cleanup after the client */ |
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282 | |||
2520 | jermar | 283 | } |
284 | |||
2518 | jermar | 285 | int main(int argc, char **argv) |
286 | { |
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2520 | jermar | 287 | ipcarg_t phonead; |
288 | |||
2526 | jermar | 289 | list_initialize(&fs_head); |
2520 | jermar | 290 | async_set_client_connection(vfs_connection); |
291 | ipc_connect_to_me(PHONE_NS, SERVICE_VFS, 0, &phonead); |
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292 | async_manager(); |
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2518 | jermar | 293 | return 0; |
294 | } |
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295 | |||
296 | /** |
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297 | * @} |
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298 | */ |