1 | .. SPDX-License-Identifier: CC-BY-SA-4.0 |
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2 | |
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3 | .. Copyright (C) 2012, 2016 Chris Johns <chrisj@rtems.org> |
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4 | |
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5 | RTEMS Third-Party Packages |
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6 | -------------------------- |
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7 | |
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8 | This section describes how to build and add an RTEMS third-party package to the |
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9 | RSB. |
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10 | |
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11 | A third-party package is a library or software package built to run on RTEMS, |
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12 | examples are NTP, Net-Snmp, libjpeg or Python. These pieces of software can be |
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13 | used to help build RTEMS applications. The package is built for a specific |
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14 | BSP and so requires a working RTEMS tool chain and an installed RTEMS Board |
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15 | Support Package (BSP). |
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16 | |
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17 | The RSB support for building third-party packages is based around the *pkconfig* |
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18 | files (PC) installed with the BSP. The pkgconfig support in RTEMS is considered |
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19 | experimental and can have some issues for some BSPs. This issue is rooted deep |
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20 | in the RTEMS build system. If you have any issues with this support please ask |
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21 | on the RTEMS developers mailing list. |
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22 | |
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23 | Vertical Integration |
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24 | ^^^^^^^^^^^^^^^^^^^^ |
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25 | |
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26 | The RSB supports horizontal integration with support for multiple |
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27 | architectures. Adding packages to the RSB as libraries is vertical |
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28 | integration. Building the GCC tool chain requires you build an assembler before |
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29 | you build a compiler. The same can be done for third-party libraries, you can |
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30 | crate build sets that stack library dependences vertically to create a *stack*. |
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31 | |
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32 | Building |
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33 | ^^^^^^^^ |
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34 | |
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35 | To build a package you need to have a suitable RTEMS tool chain and RTEMS BSP |
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36 | installed. The set builder command line requires you provide the tools path, |
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37 | the RTEMS host, and the prefix path to the installed RTEMS BSP. The prefix |
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38 | needs to be the same as the prefix used to build RTEMS. |
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39 | |
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40 | To build Net-SNMP the command is: |
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41 | |
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42 | .. code-block:: shell |
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43 | |
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44 | $ cd rtems-source-builder/rtems |
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45 | $ ../source-builder/sb-set-builder --log=log_sis_net_snmp \ |
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46 | --prefix=$HOME/development/rtems/bsps/4.11 \ |
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47 | --with-tools=$HOME/development/rtems/4.11 \ |
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48 | --host=sparc-rtems4.11 --with-rtems-bsp=erc32 4.11/net-mgmt/net-snmp |
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49 | RTEMS Source Builder - Set Builder, v0.3.0 |
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50 | Build Set: 4.11/net-mgmt/net-snmp |
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51 | config: net-mgmt/net-snmp-5.7.2.1-1.cfg |
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52 | package: net-snmp-5.7.2.1-sparc-rtems4.11-1 |
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53 | building: net-snmp-5.7.2.1-sparc-rtems4.11-1 |
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54 | installing: net-snmp-5.7.2.1-sparc-rtems4.11-1 -> /Users/chris/development/rtems/bsps/4.11 |
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55 | cleaning: net-snmp-5.7.2.1-sparc-rtems4.11-1 |
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56 | Build Set: Time 0:01:10.651926 |
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57 | |
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58 | Adding |
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59 | ^^^^^^ |
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60 | |
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61 | Adding a package requires you first build it manually by downloading the source |
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62 | for the package and building it for RTEMS using the command line of a standard |
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63 | shell. If the package has not been ported to RTEMS you will need to port it and |
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64 | this may require you asking questions on the package's user or development |
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65 | support lists as well as RTEMS's developers list. Your porting effort may end |
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66 | up with a patch. RTEMS requires a patch be submitted upstream to the project's |
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67 | community as well as RTEMS so it can be added to the RTEMS Tools git |
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68 | repository. A patch in the RTEMS Tools git reposiitory can then be referenced |
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69 | by an RSB configuration file. |
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70 | |
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71 | A package may create executables, for example NTP normally creates executables |
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72 | such as ``ntdp``, ``ntpupdate``, or ``ntpdc``. These executables can be useful |
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73 | when testing the package however they are of limited use by RTEMS users because |
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74 | they cannot be directly linked into a user application. Users need to link to |
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75 | the functions in these executables or even the executable as a function placed |
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76 | in libraries. If the package does not export the code in a suitable manner |
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77 | please contact the project's commuinity and see if you can work them to provide |
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78 | a way for the code to be exported. This may be difficult because exporting |
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79 | internal headers and functions opens the project up to API compatibility issues |
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80 | they did not have before. In the simplest case attempting to get the code into |
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81 | a static library with a single call entry point exported in a header would give |
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82 | RTEMS user's access to the package's main functionality. |
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83 | |
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84 | A package requires 3 files to be created: |
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85 | |
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86 | - The first file is the RTEMS build set file and it resides in the |
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87 | ``rtems/config/%{rtems_version}`` path in a directory tree based on the |
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88 | FreeBSD ports collection. For the NTP package and RTEMS 4.11 this is |
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89 | ``rtems/config/4.11/net/ntp.bset``. If you do not know the FreeBSD port path |
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90 | for the package you are adding please ask. The build set file references a |
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91 | specific configuration file therefore linking the RTEMS version to a specific |
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92 | version of the package you are adding. Updating the package to a new version |
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93 | requires changing the build set to the new configuration file. |
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94 | |
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95 | - The second file is an RTEMS version specific configuration file and it |
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96 | includes the RSB RTEMS BSP support. These configuration files reside in the |
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97 | ``rtems/config`` tree again under the FreeBSD port's path name. For example |
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98 | the NTP package is found in the ``net`` directory of the FreeBSD ports tree |
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99 | so the NTP configuration path is ``rtems/config/net/ntp-4.2.6p5-1.cfg`` for |
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100 | that specific version. The configuration file name typically provides version |
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101 | specific references and the RTEMS build set file references a specific |
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102 | version. This configuration file references the build configuration file held |
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103 | in the common configuration file tree. |
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104 | |
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105 | - The build configuration. This is a common script that builds the package. It |
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106 | resides in the ``source-builder/config`` directory and typically has the |
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107 | packages's name with the major version number. If the build script does not |
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108 | change for each major version number a *common* base script can be created |
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109 | and included by each major version configuration script. The *gcc* compiler |
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110 | configuration is an example. This approach lets you branch a version if |
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111 | something changes that is not backwards compatible. It is important to keep |
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112 | existing versions building. The build configuration should be able to build a |
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113 | package for the build host as well as RTEMS as the RSB abstracts the RTEMS |
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114 | specific parts. See :ref:`Configuration` for more details. |
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115 | |
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116 | BSP Support |
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117 | ^^^^^^^^^^^ |
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118 | |
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119 | The RSB provides support to help build packages for RTEMS. RTEMS applications |
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120 | can be viewed as statically linked executables operating in a single address |
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121 | space. As a result only the static libraries a package builds are required and |
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122 | these libraries need to be ABI compatible with the RTEMS kernel and application |
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123 | code meaning compiler ABI flags cannot be mixed when building code. The 3rd |
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124 | party package need to use the same compiler flags as the BSP used to build |
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125 | RTEMS. |
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126 | |
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127 | .. note:: |
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128 | |
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129 | RTEMS's dynamic loading support does not use the standard shared library |
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130 | support found in Unix and the ELF standard. RTEMS's loader uses static |
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131 | libraries and the runtime link editor performs a similar function to a host |
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132 | based static linker. RTEMS will only reference static libraries even if |
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133 | dynamic libraries are created and installed. |
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134 | |
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135 | The RSB provides the configuration file ``rtems/config/rtems-bsp.cfg`` to |
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136 | support building third-party packages and you need to include this file in your |
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137 | RTEMS version specific configuration file. For example the Net-SNMP |
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138 | configuration file ``rtems/config/net-mgmt/net-snmp-5.7.2.1-1.cfg``: |
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139 | |
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140 | .. code-block:: spec |
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141 | |
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142 | # |
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143 | # NetSNMP 5.7.2.1 |
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144 | # |
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145 | %if %{release} == %{nil} |
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146 | %define release 1 <1> |
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147 | %endif |
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148 | |
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149 | %include %{_configdir}/rtems-bsp.cfg <2> |
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150 | |
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151 | # |
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152 | # NetSNMP Version |
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153 | # |
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154 | %define net_snmp_version 5.7.2.1 <3> |
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155 | |
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156 | # |
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157 | # We need some special flags to build this version. |
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158 | # |
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159 | %define net_snmp_cflags <4> -DNETSNMP_CAN_USE_SYSCTL=1 -DARP_SCAN_FOUR_ARGUMENTS=1 -DINP_IPV6=0 |
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160 | |
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161 | # |
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162 | # Patch for RTEMS support. |
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163 | # |
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164 | %patch add net-snmp %{rtems_git_tools}/net-snmp/rtems-net-snmp-5.7.2.1-20140623.patch <5> |
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165 | |
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166 | # |
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167 | # NetSNMP Build configuration |
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168 | # |
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169 | %include %{_configdir}/net-snmp-5-1.cfg <6> |
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170 | |
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171 | .. topic:: Items: |
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172 | |
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173 | 1. The release number. |
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174 | |
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175 | 2. Include the RSB RTEMS BSP support. |
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176 | |
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177 | 3. The Net-SNMP package's version. |
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178 | |
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179 | 4. Add specific ``CFLAGS`` to the build process. See the |
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180 | ``net-snmp-5.7.2.1-1.cfg`` for details. |
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181 | |
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182 | 5. The RTEMS Net-SNMP patch downloaded from the RTEMS Tools git repo. |
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183 | |
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184 | 6. The Net-SNMP standard build configuration. |
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185 | |
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186 | The RSB RTEMS BSP support file ``rtems/config/rtems-bsp.cfg`` checks to make |
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187 | sure standard command line options are provided. These include ``--host`` and |
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188 | ``--with-rtems-bsp``. If the ``--with-tools`` command line option is not given |
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189 | the ``${_prefix}`` is used: |
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190 | |
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191 | .. code-block:: spec |
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192 | |
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193 | %if %{_host} == %{nil} <1> |
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194 | %error No RTEMS target specified: --host=host |
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195 | %endif |
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196 | |
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197 | %ifn %{defined with_rtems_bsp} <2> |
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198 | %error No RTEMS BSP specified: --with-rtems-bsp=bsp |
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199 | %endif |
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200 | |
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201 | %ifn %{defined with_tools} <3> |
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202 | %define with_tools %{_prefix} |
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203 | %endif |
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204 | |
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205 | # |
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206 | # Set the path to the tools. |
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207 | # |
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208 | %{path prepend %{with_tools}/bin} <4> |
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209 | |
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210 | .. topic:: Items: |
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211 | |
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212 | 1. Check the host has been set. |
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213 | |
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214 | 2. Check a BSP has been specified. |
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215 | |
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216 | 3. If no tools path has been provided assume they are under the |
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217 | ``%{_prefix}``. |
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218 | |
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219 | 4. Add the tools ``bin`` path to the system path. |
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220 | |
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221 | RTEMS exports the build flags used in *pkgconfig* (.pc) files and the RSB can |
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222 | read and manage them even when there is no pkgconfig support installed on your |
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223 | build machine. Using this support we can obtain a BSP's configuration and set |
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224 | some standard macros variables (``rtems/config/rtems-bsp.cfg``): |
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225 | |
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226 | .. code-block:: spec |
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227 | |
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228 | %{pkgconfig prefix %{_prefix}/lib/pkgconfig} <1> |
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229 | %{pkgconfig crosscompile yes} <2> |
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230 | %{pkgconfig filter-flags yes} <3> |
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231 | |
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232 | # |
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233 | # The RTEMS BSP Flags |
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234 | # |
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235 | %define rtems_bsp %{with_rtems_bsp} |
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236 | %define rtems_bsp_ccflags %{pkgconfig ccflags %{_host}-%{rtems_bsp}} <4> |
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237 | %define rtems_bsp_cflags %{pkgconfig cflags %{_host}-%{rtems_bsp}} |
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238 | %define rtems_bsp_ldflags %{pkgconfig ldflags %{_host}-%{rtems_bsp}} |
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239 | %define rtems_bsp_libs %{pkgconfig libs %{_host}-%{rtems_bsp}} |
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240 | |
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241 | .. topic:: Items: |
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242 | |
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243 | 1. Set the path to the BSP's pkgconfig file. |
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244 | |
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245 | 2. Let pkgconfig know this is a cross-compile build. |
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246 | |
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247 | 3. Filter flags such as warnings. Warning flags are specific to a package. |
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248 | |
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249 | 4. Ask pkgconfig for the various items we require. |
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250 | |
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251 | The flags obtain by pkgconfig and given a ``rtems_bsp_`` prefix and we uses these |
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252 | to set the RSB host support CFLAGS, LDFLAGS and LIBS flags. When we build a 3rd |
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253 | party library your host computer is the _build_ machine and RTEMS is the _host_ |
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254 | machine therefore we set the ``host`` variables |
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255 | (``rtems/config/rtems-bsp.cfg``): |
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256 | |
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257 | .. code-block:: spec |
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258 | |
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259 | %define host_cflags %{rtems_bsp_cflags} |
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260 | %define host_ldflags %{rtems_bsp_ldflags} |
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261 | %define host_libs %{rtems_bsp_libs} |
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262 | |
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263 | Finally we provide all the paths you may require when configuring a |
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264 | package. Packages by default consider the ``_prefix`` the base and install |
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265 | various files under this tree. The package you are building is specific to a |
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266 | BSP and so needs to install into the specific BSP path under the |
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267 | ``_prefix``. This allows more than BSP build of this package to be install |
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268 | under the same ``_prefix`` at the same time (``rtems/config/rtems-bsp.cfg``): |
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269 | |
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270 | .. code-block:: spec |
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271 | |
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272 | %define rtems_bsp_prefix %{_prefix}/%{_host}/%{rtems_bsp} <1> |
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273 | %define _exec_prefix %{rtems_bsp_prefix} |
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274 | %define _bindir %{_exec_prefix}/bin |
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275 | %define _sbindir %{_exec_prefix}/sbin |
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276 | %define _libexecdir %{_exec_prefix}/libexec |
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277 | %define _datarootdir %{_exec_prefix}/share |
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278 | %define _datadir %{_datarootdir} |
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279 | %define _sysconfdir %{_exec_prefix}/etc |
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280 | %define _sharedstatedir %{_exec_prefix}/com |
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281 | %define _localstatedir %{_exec_prefix}/var |
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282 | %define _includedir %{_libdir}/include |
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283 | %define _lib lib |
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284 | %define _libdir %{_exec_prefix}/%{_lib} |
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285 | %define _libexecdir %{_exec_prefix}/libexec |
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286 | %define _mandir %{_datarootdir}/man |
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287 | %define _infodir %{_datarootdir}/info |
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288 | %define _localedir %{_datarootdir}/locale |
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289 | %define _localedir %{_datadir}/locale |
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290 | %define _localstatedir %{_exec_prefix}/var |
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291 | |
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292 | .. topic:: Items: |
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293 | |
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294 | 1. The path to the BSP. |
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295 | |
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296 | When you configure a package you can reference these paths and the RSB will |
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297 | provide sensible default or in this case map them to the BSP |
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298 | (``source-builder/config/ntp-4-1.cfg``): |
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299 | |
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300 | .. code-block:: spec |
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301 | |
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302 | ../${source_dir_ntp}/configure \ <1> |
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303 | --host=%{_host} \ |
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304 | --prefix=%{_prefix} \ |
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305 | --bindir=%{_bindir} \ |
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306 | --exec_prefix=%{_exec_prefix} \ |
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307 | --includedir=%{_includedir} \ |
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308 | --libdir=%{_libdir} \ |
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309 | --libexecdir=%{_libexecdir} \ |
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310 | --mandir=%{_mandir} \ |
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311 | --infodir=%{_infodir} \ |
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312 | --datadir=%{_datadir} \ |
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313 | --disable-ipv6 \ |
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314 | --disable-HOPFPCI |
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315 | |
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316 | .. topic:: Items: |
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317 | |
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318 | 1. The configure command for NTP. |
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319 | |
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320 | RTEMS BSP Configuration |
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321 | ^^^^^^^^^^^^^^^^^^^^^^^ |
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322 | |
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323 | To build a package for RTEMS you need to build it with the matching BSP |
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324 | configuration. A BSP can be built with specific flags that require all code |
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325 | being used needs to be built with the same flags. |
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