1 | /**
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2 | * @file
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3 | * HTTPD custom file system example
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4 | *
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5 | * This file demonstrates how to add support for an external file system to httpd.
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6 | * It provides access to the specified root directory and uses stdio.h file functions
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7 | * to read files.
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8 | *
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9 | * ATTENTION: This implementation is *not* secure: no checks are added to ensure
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10 | * files are only read below the specified root directory!
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11 | */
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12 |
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13 | /*
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14 | * Copyright (c) 2017 Simon Goldschmidt
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15 | * All rights reserved.
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16 | *
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17 | * Redistribution and use in source and binary forms, with or without modification,
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18 | * are permitted provided that the following conditions are met:
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19 | *
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20 | * 1. Redistributions of source code must retain the above copyright notice,
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21 | * this list of conditions and the following disclaimer.
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22 | * 2. Redistributions in binary form must reproduce the above copyright notice,
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23 | * this list of conditions and the following disclaimer in the documentation
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24 | * and/or other materials provided with the distribution.
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25 | * 3. The name of the author may not be used to endorse or promote products
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26 | * derived from this software without specific prior written permission.
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27 | *
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28 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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29 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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30 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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31 | * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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32 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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33 | * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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34 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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35 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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36 | * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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37 | * OF SUCH DAMAGE.
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38 | *
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39 | * This file is part of the lwIP TCP/IP stack.
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40 | *
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41 | * Author: Simon Goldschmidt <goldsimon@gmx.de>
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42 | *
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43 | */
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44 |
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45 | #include "lwip/opt.h"
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46 | #include "fs_example.h"
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47 |
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48 | #include "lwip/apps/fs.h"
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49 | #include "lwip/def.h"
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50 | #include "lwip/mem.h"
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51 |
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52 | #include <stdio.h>
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53 | #include <string.h>
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54 |
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55 | /** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES to 1 to enable this file system */
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56 | #ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES
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57 | #define LWIP_HTTPD_EXAMPLE_CUSTOMFILES 0
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58 | #endif
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59 |
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60 | /** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED to 1 to delay open and read
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61 | * as if e.g. reading from external SPI flash */
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62 | #ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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63 | #define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED 1
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64 | #endif
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65 |
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66 | /** define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ to the number of bytes
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67 | * to read to emulate limited transfer buffers and don't read whole files in
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68 | * one chunk.
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69 | * WARNING: lowering this slows down the connection!
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70 | */
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71 | #ifndef LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
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72 | #define LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ 0
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73 | #endif
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74 |
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75 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES
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76 |
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77 | #if !LWIP_HTTPD_CUSTOM_FILES
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78 | #error This needs LWIP_HTTPD_CUSTOM_FILES
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79 | #endif
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80 | #if !LWIP_HTTPD_DYNAMIC_HEADERS
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81 | #error This needs LWIP_HTTPD_DYNAMIC_HEADERS
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82 | #endif
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83 | #if !LWIP_HTTPD_DYNAMIC_FILE_READ
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84 | #error This wants to demonstrate read-after-open, so LWIP_HTTPD_DYNAMIC_FILE_READ is required!
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85 | #endif
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86 | #if !LWIP_HTTPD_FS_ASYNC_READ
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87 | #error This needs LWIP_HTTPD_FS_ASYNC_READ
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88 | #endif
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89 |
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90 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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91 | #include "lwip/tcpip.h"
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92 | #endif
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93 |
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94 | struct fs_custom_data {
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95 | FILE *f;
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96 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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97 | int delay_read;
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98 | fs_wait_cb callback_fn;
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99 | void *callback_arg;
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100 | #endif
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101 | };
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102 |
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103 | const char* fs_ex_root_dir;
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104 |
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105 | void
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106 | fs_ex_init(const char *httpd_root_dir)
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107 | {
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108 | fs_ex_root_dir = strdup(httpd_root_dir);
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109 | }
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110 |
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111 | #if LWIP_HTTPD_CUSTOM_FILES
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112 | int
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113 | fs_open_custom(struct fs_file *file, const char *name)
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114 | {
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115 | char full_filename[256];
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116 | FILE *f;
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117 |
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118 | snprintf(full_filename, 255, "%s%s", fs_ex_root_dir, name);
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119 | full_filename[255] = 0;
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120 |
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121 | f = fopen(full_filename, "rb");
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122 | if (f != NULL) {
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123 | if (!fseek(f, 0, SEEK_END)) {
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124 | int len = (int)ftell(f);
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125 | if(!fseek(f, 0, SEEK_SET)) {
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126 | struct fs_custom_data *data = (struct fs_custom_data *)mem_malloc(sizeof(struct fs_custom_data));
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127 | LWIP_ASSERT("out of memory?", data != NULL);
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128 | memset(file, 0, sizeof(struct fs_file));
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129 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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130 | file->len = 0; /* read size delayed */
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131 | data->delay_read = 3;
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132 | LWIP_UNUSED_ARG(len);
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133 | #else
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134 | file->len = len;
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135 | #endif
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136 | file->flags = FS_FILE_FLAGS_HEADER_PERSISTENT;
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137 | data->f = f;
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138 | file->pextension = data;
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139 | return 1;
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140 | }
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141 | }
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142 | fclose(f);
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143 | }
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144 | return 0;
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145 | }
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146 |
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147 | void
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148 | fs_close_custom(struct fs_file *file)
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149 | {
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150 | if (file && file->pextension) {
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151 | struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
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152 | if (data->f != NULL) {
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153 | fclose(data->f);
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154 | data->f = NULL;
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155 | }
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156 | mem_free(data);
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157 | }
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158 | }
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159 |
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160 | #if LWIP_HTTPD_FS_ASYNC_READ
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161 | u8_t
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162 | fs_canread_custom(struct fs_file *file)
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163 | {
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164 | /* This function is only necessary for asynchronous I/O:
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165 | If reading would block, return 0 and implement fs_wait_read_custom() to call the
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166 | supplied callback if reading works. */
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167 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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168 | struct fs_custom_data *data;
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169 | LWIP_ASSERT("file != NULL", file != NULL);
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170 | data = (struct fs_custom_data *)file->pextension;
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171 | if (data == NULL) {
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172 | /* file transfer has been completed already */
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173 | LWIP_ASSERT("transfer complete", file->index == file->len);
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174 | return 1;
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175 | }
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176 | LWIP_ASSERT("data != NULL", data != NULL);
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177 | /* This just simulates a simple delay. This delay would normally come e.g. from SPI transfer */
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178 | if (data->delay_read == 3) {
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179 | /* delayed file size mode */
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180 | data->delay_read = 1;
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181 | LWIP_ASSERT("", file->len == 0);
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182 | if (!fseek(data->f, 0, SEEK_END)) {
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183 | int len = (int)ftell(data->f);
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184 | if(!fseek(data->f, 0, SEEK_SET)) {
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185 | file->len = len; /* read size delayed */
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186 | data->delay_read = 1;
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187 | return 0;
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188 | }
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189 | }
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190 | /* if we come here, something is wrong with the file */
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191 | LWIP_ASSERT("file error", 0);
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192 | }
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193 | if (data->delay_read == 1) {
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194 | /* tell read function to delay further */
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195 | }
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196 | #endif
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197 | LWIP_UNUSED_ARG(file);
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198 | return 1;
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199 | }
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200 |
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201 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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202 | static void
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203 | fs_example_read_cb(void *arg)
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204 | {
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205 | struct fs_custom_data *data = (struct fs_custom_data *)arg;
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206 | fs_wait_cb callback_fn = data->callback_fn;
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207 | void *callback_arg = data->callback_arg;
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208 | data->callback_fn = NULL;
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209 | data->callback_arg = NULL;
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210 |
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211 | LWIP_ASSERT("no callback_fn", callback_fn != NULL);
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212 |
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213 | callback_fn(callback_arg);
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214 | }
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215 | #endif
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216 |
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217 | u8_t
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218 | fs_wait_read_custom(struct fs_file *file, fs_wait_cb callback_fn, void *callback_arg)
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219 | {
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220 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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221 | err_t err;
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222 | struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
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223 | LWIP_ASSERT("data not set", data != NULL);
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224 | data->callback_fn = callback_fn;
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225 | data->callback_arg = callback_arg;
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226 | err = tcpip_try_callback(fs_example_read_cb, data);
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227 | LWIP_ASSERT("out of queue elements?", err == ERR_OK);
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228 | LWIP_UNUSED_ARG(err);
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229 | #else
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230 | LWIP_ASSERT("not implemented in this example configuration", 0);
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231 | #endif
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232 | LWIP_UNUSED_ARG(file);
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233 | LWIP_UNUSED_ARG(callback_fn);
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234 | LWIP_UNUSED_ARG(callback_arg);
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235 | /* Return
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236 | - 1 if ready to read (at least one byte)
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237 | - 0 if reading should be delayed (call 'tcpip_callback(callback_fn, callback_arg)' when ready) */
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238 | return 1;
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239 | }
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240 |
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241 | int
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242 | fs_read_async_custom(struct fs_file *file, char *buffer, int count, fs_wait_cb callback_fn, void *callback_arg)
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243 | {
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244 | struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
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245 | FILE *f;
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246 | int len;
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247 | int read_count = count;
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248 | LWIP_ASSERT("data not set", data != NULL);
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249 |
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250 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_DELAYED
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251 | /* This just simulates a delay. This delay would normally come e.g. from SPI transfer */
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252 | LWIP_ASSERT("invalid state", data->delay_read >= 0 && data->delay_read <= 2);
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253 | if (data->delay_read == 2) {
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254 | /* no delay next time */
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255 | data->delay_read = 0;
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256 | return FS_READ_DELAYED;
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257 | } else if (data->delay_read == 1) {
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258 | err_t err;
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259 | /* execute requested delay */
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260 | data->delay_read = 2;
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261 | LWIP_ASSERT("duplicate callback request", data->callback_fn == NULL);
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262 | data->callback_fn = callback_fn;
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263 | data->callback_arg = callback_arg;
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264 | err = tcpip_try_callback(fs_example_read_cb, data);
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265 | LWIP_ASSERT("out of queue elements?", err == ERR_OK);
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266 | LWIP_UNUSED_ARG(err);
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267 | return FS_READ_DELAYED;
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268 | }
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269 | /* execute this read but delay the next one */
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270 | data->delay_read = 1;
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271 | #endif
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272 |
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273 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
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274 | read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ);
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275 | #endif
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276 |
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277 | f = data->f;
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278 | len = (int)fread(buffer, 1, read_count, f);
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279 |
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280 | LWIP_UNUSED_ARG(callback_fn);
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281 | LWIP_UNUSED_ARG(callback_arg);
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282 |
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283 | file->index += len;
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284 |
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285 | /* Return
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286 | - FS_READ_EOF if all bytes have been read
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287 | - FS_READ_DELAYED if reading is delayed (call 'tcpip_callback(callback_fn, callback_arg)' when done) */
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288 | if (len == 0) {
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289 | /* all bytes read already */
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290 | return FS_READ_EOF;
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291 | }
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292 | return len;
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293 | }
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294 |
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295 | #else /* LWIP_HTTPD_FS_ASYNC_READ */
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296 | int
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297 | fs_read_custom(struct fs_file *file, char *buffer, int count)
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298 | {
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299 | struct fs_custom_data *data = (struct fs_custom_data *)file->pextension;
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300 | FILE *f;
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301 | int len;
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302 | int read_count = count;
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303 | LWIP_ASSERT("data not set", data != NULL);
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304 |
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305 | #if LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ
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306 | read_count = LWIP_MIN(read_count, LWIP_HTTPD_EXAMPLE_CUSTOMFILES_LIMIT_READ);
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307 | #endif
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308 |
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309 | f = data->f;
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310 | len = (int)fread(buffer, 1, read_count, f);
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311 |
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312 | file->index += len;
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313 |
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314 | /* Return FS_READ_EOF if all bytes have been read */
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315 | return len;
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316 | }
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317 |
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318 | #endif /* LWIP_HTTPD_FS_ASYNC_READ */
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319 | #endif /* LWIP_HTTPD_CUSTOM_FILES */
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320 |
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321 | #endif /* LWIP_HTTPD_EXAMPLE_CUSTOMFILES */
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