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4534 | svoboda | 1 | /* |
2 | * Copyright (c) 2009 Jiri Svoboda |
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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 bd |
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30 | * @{ |
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31 | */ |
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32 | |||
33 | /** |
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34 | * @file |
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35 | * @brief File-backed block device driver |
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36 | * |
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37 | * Allows accessing a file as a block device. Useful for, e.g., mounting |
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38 | * a disk image. |
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39 | */ |
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40 | |||
41 | #include <stdio.h> |
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42 | #include <unistd.h> |
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43 | #include <ipc/ipc.h> |
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44 | #include <ipc/bd.h> |
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45 | #include <async.h> |
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46 | #include <as.h> |
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47 | #include <futex.h> |
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48 | #include <devmap.h> |
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49 | #include <sys/types.h> |
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50 | #include <errno.h> |
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51 | #include <bool.h> |
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52 | |||
53 | #define NAME "file_bd" |
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54 | |||
55 | static size_t comm_size; |
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56 | static FILE *img; |
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57 | |||
58 | static dev_handle_t dev_handle; |
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59 | static atomic_t dev_futex = FUTEX_INITIALIZER; |
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60 | |||
61 | static int file_bd_init(const char *fname); |
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62 | static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall); |
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4545 | svoboda | 63 | static int file_bd_read(off_t blk_idx, size_t size, void *buf); |
64 | static int file_bd_write(off_t blk_idx, size_t size, void *buf); |
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4534 | svoboda | 65 | |
66 | int main(int argc, char **argv) |
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67 | { |
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68 | int rc; |
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69 | |||
70 | printf(NAME ": File-backed block device driver\n"); |
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71 | |||
72 | if (argc != 3) { |
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73 | printf("Expected two arguments (image name, device name).\n"); |
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74 | return -1; |
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75 | } |
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76 | |||
77 | if (file_bd_init(argv[1]) != EOK) |
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78 | return -1; |
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79 | |||
80 | rc = devmap_device_register(argv[2], &dev_handle); |
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81 | if (rc != EOK) { |
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82 | devmap_hangup_phone(DEVMAP_DRIVER); |
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83 | printf(NAME ": Unable to register device %s.\n", |
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84 | argv[2]); |
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85 | return rc; |
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86 | } |
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87 | |||
88 | printf(NAME ": Accepting connections\n"); |
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89 | async_manager(); |
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90 | |||
91 | /* Not reached */ |
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92 | return 0; |
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93 | } |
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94 | |||
95 | static int file_bd_init(const char *fname) |
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96 | { |
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97 | int rc; |
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98 | |||
99 | rc = devmap_driver_register(NAME, file_bd_connection); |
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100 | if (rc < 0) { |
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101 | printf(NAME ": Unable to register driver.\n"); |
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102 | return rc; |
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103 | } |
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104 | |||
105 | img = fopen(fname, "rb+"); |
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106 | if (img == NULL) |
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107 | return EINVAL; |
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108 | |||
109 | return EOK; |
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110 | } |
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111 | |||
112 | static void file_bd_connection(ipc_callid_t iid, ipc_call_t *icall) |
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113 | { |
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114 | void *fs_va = NULL; |
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115 | ipc_callid_t callid; |
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116 | ipc_call_t call; |
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117 | ipcarg_t method; |
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118 | int flags; |
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119 | int retval; |
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120 | off_t idx; |
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4545 | svoboda | 121 | size_t size; |
4534 | svoboda | 122 | |
123 | /* Answer the IPC_M_CONNECT_ME_TO call. */ |
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124 | ipc_answer_0(iid, EOK); |
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125 | |||
126 | if (!ipc_share_out_receive(&callid, &comm_size, &flags)) { |
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127 | ipc_answer_0(callid, EHANGUP); |
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128 | return; |
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129 | } |
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130 | |||
131 | fs_va = as_get_mappable_page(comm_size); |
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132 | if (fs_va == NULL) { |
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133 | ipc_answer_0(callid, EHANGUP); |
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134 | return; |
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135 | } |
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136 | |||
137 | (void) ipc_share_out_finalize(callid, fs_va); |
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138 | |||
139 | while (1) { |
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140 | callid = async_get_call(&call); |
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141 | method = IPC_GET_METHOD(call); |
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142 | switch (method) { |
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143 | case IPC_M_PHONE_HUNGUP: |
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144 | /* The other side has hung up. */ |
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145 | ipc_answer_0(callid, EOK); |
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146 | return; |
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147 | case BD_READ_BLOCK: |
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148 | case BD_WRITE_BLOCK: |
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149 | idx = IPC_GET_ARG1(call); |
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150 | size = IPC_GET_ARG2(call); |
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151 | if (size > comm_size) { |
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152 | retval = EINVAL; |
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153 | break; |
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154 | } |
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155 | if (method == BD_READ_BLOCK) |
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156 | retval = file_bd_read(idx, size, fs_va); |
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157 | else |
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158 | retval = file_bd_write(idx, size, fs_va); |
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159 | break; |
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160 | default: |
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161 | retval = EINVAL; |
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162 | break; |
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163 | } |
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164 | ipc_answer_0(callid, retval); |
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165 | } |
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166 | } |
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167 | |||
4545 | svoboda | 168 | static int file_bd_read(off_t blk_idx, size_t size, void *buf) |
4534 | svoboda | 169 | { |
170 | size_t n_rd; |
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171 | |||
172 | printf("file_bd_read\n"); |
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173 | futex_down(&dev_futex); |
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174 | |||
175 | printf("seek\n"); |
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176 | fseek(img, blk_idx * size, SEEK_SET); |
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177 | printf("read\n"); |
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178 | n_rd = fread(buf, 1, size, img); |
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179 | printf("done\n"); |
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180 | |||
181 | printf("done\n"); |
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182 | |||
183 | if (ferror(img)) { |
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184 | futex_up(&dev_futex); |
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185 | return EIO; /* Read error */ |
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186 | } |
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187 | |||
188 | futex_up(&dev_futex); |
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189 | |||
190 | if (n_rd < size) |
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191 | return EINVAL; /* Read beyond end of disk */ |
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192 | |||
193 | return EOK; |
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194 | } |
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195 | |||
4545 | svoboda | 196 | static int file_bd_write(off_t blk_idx, size_t size, void *buf) |
4534 | svoboda | 197 | { |
198 | size_t n_wr; |
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199 | |||
200 | futex_down(&dev_futex); |
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201 | |||
202 | fseek(img, blk_idx * size, SEEK_SET); |
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203 | n_wr = fread(buf, 1, size, img); |
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204 | |||
205 | if (ferror(img) || n_wr < size) { |
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206 | futex_up(&dev_futex); |
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207 | return EIO; /* Write error */ |
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208 | } |
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209 | |||
210 | futex_up(&dev_futex); |
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211 | |||
212 | return EOK; |
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213 | } |
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214 | |||
215 | /** |
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216 | * @} |
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217 | */ |