ARM platform cross compilation | MQTT-mosquitto

There are two ways to compile mosquitto: cmake and make. Windows and Mac platforms use cmake compilation, and other platforms, including Linux platforms, use make to compile directly. Compiling mosquitto under Windows 7 details the steps to compile mosquitto under Windows 7.

This article introduces the compilation steps of mosquitto for a certain ARM platform.

Compiler Environment

Host: Ubuntu 16.04

Host: ARM, Cortex-A55

Cross compiler: aarch64-linux-gnu-gcc, 7.2.1 20171011 (Linaro GCC 7.2-2017.11)

Compilation steps

Download the latest mosquitto source code package from the official website of mosquitto. The host machine for this compilation is Ubuntu system, and the makefile provided by mosquitto is used directly for compilation. The compilation environment depends on the following:

cJSON: Enabled by default so that the client can output content in cJSON format. Disable the dependency by making WITH_CJSON=no.

openssl: provides ssl support for mosquitto, enabled by default, and disabled by making WITH_TLS=no;

pthreads: provides multi-thread support for mosquitto. Since the compilation environment is Linux system, the pthreads API environment is supported by default.

Prepare

OpenSSL

For the cross-compilation steps of openssl, please refer to Cross-compile OpenSSL.

cJSON

Download the latest cJSON source code and unzip it.

mkdir build

cmake -DCMAKE_INSTALL_PREFIX=/path/to/install -DCMAKE_C_COMPILER=aarch64-linux-gnu-gcc -DCMAKE_CXX_COMPILER=aarch64-linux-gnu-g++

make

make install

Compile

Unzip the mosquitto source package and execute the following command to compile:

make CC=aarch64-linux-gnu-gcc CXX=aarch64-linux-gnu-g++ CFLAGS="-I /path/to/openssl/install/include -I /path/to/cJson/install/include" LDFLAGS="-L /path/to/openssl/install/lib64 -L /path/to/cJson/install/lib -lssl -lcrypto -lcjson"

CC and CXX are used to specify the gcc and g++ compilers for the target platform;

CFLAGS: used to specify the installation directory of openssl and cjson header files;

LDFLAGS: used to specify the installation directory of openssl and cjson dynamic libraries;

After the compilation is complete, execute make install to install.

test

Copy cJSON, openssl, and mosquitto dynamic libraries to the target system;

Set LD_LIBRARY_PATH to specify the installation location of the above three types of dynamic libraries on the target system;

Copy the mosquitto_ctrl mosquitto_passwd mosquitto_pub mosquitto_rr mosquitto_sub test tools to the target system;

Here we take mosquitto_sub as an example to test the mosquitto subscription function. The example is as follows:

mosquitto_sub -h host_addr -p port -u username -P passwd -t the_topic_sub

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-h: specifies the server address of mqtt broker;

-p: specifies the server port number of the mqtt broker;

-u: specifies the server login username of mqtt broker;

-P: specifies the server login password of mqtt broker;

-t: Specifies the topic to be subscribed locally.