1 | /*
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2 | * Copyright (c) 2008 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 |
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29 | /** @addtogroup fs
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30 | * @{
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31 | */
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32 |
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33 | /**
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34 | * @file vfs_register.c
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35 | * @brief
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36 | */
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37 |
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38 | #include <ipc/services.h>
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39 | #include <async.h>
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40 | #include <fibril.h>
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41 | #include <fibril_synch.h>
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42 | #include <errno.h>
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43 | #include <stdio.h>
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44 | #include <stdlib.h>
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45 | #include <str.h>
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46 | #include <ctype.h>
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47 | #include <bool.h>
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48 | #include <adt/list.h>
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49 | #include <as.h>
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50 | #include <assert.h>
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51 | #include <atomic.h>
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52 | #include "vfs.h"
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53 |
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54 | FIBRIL_CONDVAR_INITIALIZE(fs_list_cv);
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55 | FIBRIL_MUTEX_INITIALIZE(fs_list_lock);
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56 | LIST_INITIALIZE(fs_list);
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57 |
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58 | atomic_t fs_handle_next = {
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59 | .count = 1
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60 | };
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61 |
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62 | /** Verify the VFS info structure.
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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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68 | */
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69 | static bool vfs_info_sane(vfs_info_t *info)
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70 | {
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71 | int i;
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72 |
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73 | /*
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74 | * Check if the name is non-empty and is composed solely of ASCII
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75 | * characters [a-z]+[a-z0-9_-]*.
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76 | */
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77 | if (!islower(info->name[0])) {
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78 | dprintf("The name doesn't start with a lowercase character.\n");
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79 | return false;
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80 | }
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81 |
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82 | for (i = 1; i < FS_NAME_MAXLEN; i++) {
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83 | if (!(islower(info->name[i]) || isdigit(info->name[i])) &&
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84 | (info->name[i] != '-') && (info->name[i] != '_')) {
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85 | if (info->name[i] == '\0') {
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86 | break;
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87 | } else {
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88 | dprintf("The name contains illegal "
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89 | "characters.\n");
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90 | return false;
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91 | }
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92 | }
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93 | }
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94 |
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95 | /*
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96 | * This check is not redundant. It ensures that the name is
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97 | * NULL-terminated, even if FS_NAME_MAXLEN characters are used.
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98 | */
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99 | if (info->name[i] != '\0') {
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100 | dprintf("The name is not properly NULL-terminated.\n");
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101 | return false;
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102 | }
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103 |
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104 | return true;
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105 | }
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106 |
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107 | /** VFS_REGISTER protocol function.
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108 | *
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109 | * @param rid Hash of the call with the request.
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110 | * @param request Call structure with the request.
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111 | *
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112 | */
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113 | void vfs_register(ipc_callid_t rid, ipc_call_t *request)
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114 | {
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115 | dprintf("Processing VFS_REGISTER request received from %p.\n",
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116 | request->in_phone_hash);
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117 |
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118 | vfs_info_t *vfs_info;
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119 | int rc = async_data_write_accept((void **) &vfs_info, false,
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120 | sizeof(vfs_info_t), sizeof(vfs_info_t), 0, NULL);
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121 |
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122 | if (rc != EOK) {
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123 | dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
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124 | rc);
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125 | async_answer_0(rid, rc);
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126 | return;
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127 | }
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128 |
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129 | /*
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130 | * Allocate and initialize a buffer for the fs_info structure.
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131 | */
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132 | fs_info_t *fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
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133 | if (!fs_info) {
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134 | dprintf("Could not allocate memory for FS info.\n");
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135 | async_answer_0(rid, ENOMEM);
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136 | return;
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137 | }
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138 |
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139 | link_initialize(&fs_info->fs_link);
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140 | fs_info->vfs_info = *vfs_info;
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141 | free(vfs_info);
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142 |
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143 | dprintf("VFS info delivered.\n");
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144 |
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145 | if (!vfs_info_sane(&fs_info->vfs_info)) {
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146 | free(fs_info);
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147 | async_answer_0(rid, EINVAL);
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148 | return;
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149 | }
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150 |
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151 | fibril_mutex_lock(&fs_list_lock);
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152 |
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153 | /*
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154 | * Check for duplicit registrations.
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155 | */
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156 | if (fs_name_to_handle(fs_info->vfs_info.instance,
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157 | fs_info->vfs_info.name, false)) {
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158 | /*
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159 | * We already register a fs like this.
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160 | */
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161 | dprintf("FS is already registered.\n");
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162 | fibril_mutex_unlock(&fs_list_lock);
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163 | free(fs_info);
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164 | async_answer_0(rid, EEXISTS);
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165 | return;
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166 | }
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167 |
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168 | /*
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169 | * Add fs_info to the list of registered FS's.
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170 | */
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171 | dprintf("Inserting FS into the list of registered file systems.\n");
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172 | list_append(&fs_info->fs_link, &fs_list);
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173 |
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174 | /*
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175 | * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
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176 | * that a callback connection is created and we have a phone through
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177 | * which to forward VFS requests to it.
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178 | */
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179 | fs_info->sess = async_callback_receive(EXCHANGE_PARALLEL);
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180 | if (!fs_info->sess) {
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181 | dprintf("Callback connection expected\n");
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182 | list_remove(&fs_info->fs_link);
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183 | fibril_mutex_unlock(&fs_list_lock);
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184 | free(fs_info);
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185 | async_answer_0(rid, EINVAL);
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186 | return;
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187 | }
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188 |
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189 | dprintf("Callback connection to FS created.\n");
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190 |
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191 | /*
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192 | * The client will want us to send him the address space area with PLB.
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193 | */
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194 |
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195 | size_t size;
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196 | ipc_callid_t callid;
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197 | if (!async_share_in_receive(&callid, &size)) {
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198 | dprintf("Unexpected call, method = %d\n", IPC_GET_IMETHOD(call));
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199 | list_remove(&fs_info->fs_link);
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200 | fibril_mutex_unlock(&fs_list_lock);
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201 | async_hangup(fs_info->sess);
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202 | free(fs_info);
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203 | async_answer_0(callid, EINVAL);
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204 | async_answer_0(rid, EINVAL);
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205 | return;
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206 | }
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207 |
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208 | /*
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209 | * We can only send the client address space area PLB_SIZE bytes long.
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210 | */
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211 | if (size != PLB_SIZE) {
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212 | dprintf("Client suggests wrong size of PFB, size = %d\n", size);
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213 | list_remove(&fs_info->fs_link);
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214 | fibril_mutex_unlock(&fs_list_lock);
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215 | async_hangup(fs_info->sess);
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216 | free(fs_info);
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217 | async_answer_0(callid, EINVAL);
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218 | async_answer_0(rid, EINVAL);
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219 | return;
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220 | }
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221 |
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222 | /*
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223 | * Commit to read-only sharing the PLB with the client.
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224 | */
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225 | (void) async_share_in_finalize(callid, plb,
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226 | AS_AREA_READ | AS_AREA_CACHEABLE);
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227 |
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228 | dprintf("Sharing PLB.\n");
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229 |
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230 | /*
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231 | * That was it. The FS has been registered.
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232 | * In reply to the VFS_REGISTER request, we assign the client file
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233 | * system a global file system handle.
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234 | */
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235 | fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);
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236 | async_answer_1(rid, EOK, (sysarg_t) fs_info->fs_handle);
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237 |
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238 | fibril_condvar_broadcast(&fs_list_cv);
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239 | fibril_mutex_unlock(&fs_list_lock);
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240 |
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241 | dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
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242 | FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
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243 | }
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244 |
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245 | /** Begin an exchange for a given file system handle
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246 | *
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247 | * @param handle File system handle.
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248 | *
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249 | * @return Exchange for a multi-call request.
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250 | * @return NULL if no such file exists.
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251 | *
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252 | */
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253 | async_exch_t *vfs_exchange_grab(fs_handle_t handle)
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254 | {
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255 | /*
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256 | * For now, we don't try to be very clever and very fast.
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257 | * We simply lookup the session in fs_list and
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258 | * begin an exchange.
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259 | */
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260 | fibril_mutex_lock(&fs_list_lock);
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261 |
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262 | list_foreach(fs_list, cur) {
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263 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
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264 |
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265 | if (fs->fs_handle == handle) {
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266 | fibril_mutex_unlock(&fs_list_lock);
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267 |
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268 | assert(fs->sess);
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269 | async_exch_t *exch = async_exchange_begin(fs->sess);
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270 |
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271 | assert(exch);
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272 | return exch;
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273 | }
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274 | }
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275 |
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276 | fibril_mutex_unlock(&fs_list_lock);
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277 |
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278 | return NULL;
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279 | }
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280 |
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281 | /** End VFS server exchange.
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282 | *
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283 | * @param exch VFS server exchange.
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284 | *
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285 | */
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286 | void vfs_exchange_release(async_exch_t *exch)
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287 | {
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288 | async_exchange_end(exch);
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289 | }
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290 |
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291 | /** Convert file system name to its handle.
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292 | *
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293 | * @param name File system name.
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294 | * @param lock If true, the function will lock and unlock the
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295 | * fs_list_lock.
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296 | *
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297 | * @return File system handle or zero if file system not found.
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298 | *
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299 | */
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300 | fs_handle_t fs_name_to_handle(unsigned int instance, char *name, bool lock)
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301 | {
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302 | int handle = 0;
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303 |
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304 | if (lock)
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305 | fibril_mutex_lock(&fs_list_lock);
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306 |
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307 | list_foreach(fs_list, cur) {
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308 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
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309 | if (str_cmp(fs->vfs_info.name, name) == 0 &&
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310 | instance == fs->vfs_info.instance) {
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311 | handle = fs->fs_handle;
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312 | break;
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313 | }
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314 | }
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315 |
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316 | if (lock)
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317 | fibril_mutex_unlock(&fs_list_lock);
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318 |
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319 | return handle;
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320 | }
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321 |
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322 | /** Find the VFS info structure.
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323 | *
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324 | * @param handle FS handle for which the VFS info structure is sought.
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325 | *
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326 | * @return VFS info structure on success or NULL otherwise.
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327 | *
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328 | */
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329 | vfs_info_t *fs_handle_to_info(fs_handle_t handle)
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330 | {
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331 | vfs_info_t *info = NULL;
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332 |
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333 | fibril_mutex_lock(&fs_list_lock);
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334 | list_foreach(fs_list, cur) {
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335 | fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
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336 | if (fs->fs_handle == handle) {
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337 | info = &fs->vfs_info;
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338 | break;
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339 | }
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340 | }
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341 | fibril_mutex_unlock(&fs_list_lock);
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342 |
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343 | return info;
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344 | }
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345 |
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346 | /**
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347 | * @}
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348 | */
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