implemented modbus tcp shm client

Author: NikolasK-source

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "libs/cxxopts"]
+	path = libs/cxxopts
+	url = git@github.com:NikolasK-source/cxxopts.git
+[submodule "libs/libmodbus"]
+	path = libs/libmodbus
+	url = https://github.com/stephane/libmodbus

CMakeLists.txt

@@ -4,23 +4,23 @@ cmake_minimum_required(VERSION 3.13.4 FATAL_ERROR)
 # ======================================================================================================================
 
 # project
-project(CMAKE_Template_Project LANGUAGES CXX VERSION 0.0.1)
+project(Modbus_TCP_client_shm LANGUAGES CXX VERSION 0.0.1)
 
 # settings
-set(Target "Template_Project")    # Executable name (without file extension!)
-set(STANDARD 20)                  # C++ Standard
+set(Target "Modbus_TCP_client_shm")    # Executable name (without file extension!)
+set(STANDARD 17)                  # C++ Standard
 set(ARCHITECTURE "native")        # CPU architecture to optimize for (only relevant if OPTIMIZE_FOR_ARCHITECTURE is ON)
 
 # options
-option(BUILD_DOC "Build documentation" ON)
+option(BUILD_DOC "Build documentation" OFF)
 option(COMPILER_WARNINGS "Enable compiler warnings" ON)
-option(ENABLE_MULTITHREADING "Link the default multithreading library for the current target system" ON)
+option(ENABLE_MULTITHREADING "Link the default multithreading library for the current target system" OFF)
 option(MAKE_32_BIT_BINARY "Compile as 32 bit application. No effect on 32 bit Systems" OFF)
-option(OPENMP "enable openmp" ON)
+option(OPENMP "enable openmp" OFF)
 option(OPTIMIZE_DEBUG "apply optimizations also in debug mode" ON)
 option(CLANG_FORMAT "use clang-format" ON)
 option(CLANG_TIDY "use clang-tidy" OFF)
-option(OPTIMIZE_FOR_ARCHITECTURE "enable optimizations for specified architecture" ON)
+option(OPTIMIZE_FOR_ARCHITECTURE "enable optimizations for specified architecture" OFF)
 option(LTO_ENABLED "enable interprocedural and link time optimizations" ON)
 option(COMPILER_EXTENSIONS "enable compiler specific C++ extensions" OFF)
 

Doxyfile.in

@@ -32,7 +32,7 @@ DOXYFILE_ENCODING      = UTF-8
 # title of most generated pages and in a few other places.
 # The default value is: My Project.
 
-PROJECT_NAME           = "CMAKE Template Project" # TODO ----------------------------------------------- !!! REPLACE !!!
+PROJECT_NAME           = "Modbus TCP Client - Shared Memory"
 
 # The PROJECT_NUMBER tag can be used to enter a project or revision number. This
 # could be handy for archiving the generated documentation or if some version
@@ -44,7 +44,7 @@ PROJECT_NUMBER         =
 # for a project that appears at the top of each page and should give viewer a
 # quick idea about the purpose of the project. Keep the description short.
 
-PROJECT_BRIEF          = "An empty CMAKE project as template for new projects" # TODO ------------------ !!! REPLACE !!!
+PROJECT_BRIEF          = "A modbus TCP client that stores its values in shared memory objects"
 
 # With the PROJECT_LOGO tag one can specify a logo or an icon that is included
 # in the documentation. The maximum height of the logo should not exceed 55

README.md

@@ -1,80 +1,39 @@
-# CMake Project template
-
-This repository is a template for CMake C++ Projects.
-
-## Supported Compiilers
-
-    - gcc
-    - clang
-
-## Project structure
-
-### Directory src
-Use this directory for all source files of the project.
-
-### Directory libs
-Place libraries here. This Directory is added to the include path.
-
-## Scripts
-
-### check_format.sh
-This script checks all ```*.cpp``` and ```*.hpp``` files for conformity with the file ```.clang-format```.
-
-### format.sh
-This script formats all ```*.cpp``` and ```*.hpp``` files in the src directory with clang format.
-The files are changed by it!
-
-## Options
-
-### Target
-The name of the executable that is generated.
-
-### STANDARD
-The minimum required C++ standard: 98, 03, 11, 14, 17, 20
-
-### ARCHITECTURE
-The CPU architecture for which the code is generated.
-It is only relevant if the option ```OPTIMIZE_FOR_ARCHITECTURE``` is enabled.
-
-```native``` should be the best choice in most cases.
-
-### BUILD_DOC
-Enables the automatic generation of a doxygen documentation.
-Doxygen must be installed on the system and a ```Doxyfile.in``` file must be provided.
-An additional CMake target is created.
-
-### COMPILER_WARNINGS
-Enable/Disable compiler warnings.
-
-### ENABLE_MULTITHREADING
-Link the default multithreading library for the current target system.
-Prefers ```pthread``` if available.
-
-### MAKE_32_BIT_BINARY
-Forces the compiler to generate a 32 bit application by setting the ```-m32``` flag.
-
-### OPENMP
-Enables the support for openmp.
-
-### OPTIMIZE_DEBUG
-Enables Optimization ```-O3``` also in debug configuration.
-Should only be enabled if the resulting binary is too slow.
-
-### CLANG_FORMAT
-Enable automatic formatting via clang-format.
-An additional CMake target is created.
-
-### CLANG_TIDY
-Enable static code checks with clang tidy.
-An additional CMake target is created.
-
-Not usable in this version due to contradictory warnings.
-
-### LTO_ENABLED
-Enable interprocedural and link time optimizations.
-
-### COMPILER_EXTENSIONS
-Enable compiler specific C++ extensions.
-Should be disabled for reasons of portability.
-
-
+# Modbus TCP client shm
+
+Modbus tcp client that stores its data (registers) in shared memory objects.
+
+## Build
+```
+git submodule init
+mkdir build
+cd build
+cmake .. -DCMAKE_CXX_COMPILER=$(which clang++)
+cmake -build . 
+```
+
+## Use
+```
+Modbus_TCP_client_shm [OPTION...]
+
+  -i, --ip arg            ip to listen for incoming connections (default: 
+                          0.0.0.0)
+  -p, --port arg          port to listen for incoming connections (default: 
+                          502)
+  -n, --name-prefix arg   shared memory name prefix (default: modbus_)
+      --do_registers arg  number of digital output registers (default: 
+                          65536)
+      --di_registers arg  number of digital input registers (default: 
+                          65536)
+      --ao_registers arg  number of analog output registers (default: 
+                          65536)
+      --ai_registers arg  number of analog input registers (default: 65536)
+  -m, --monitor           output all incoming and outgoing packets to 
+                          stdout
+  -r, --reconnect         do not terminate if Master disconnects.
+  -h, --help              print usage
+```
+
+## Libraries
+This application uses the following libraries:
+- cxxopts by jarro2783 (https://github.com/jarro2783/cxxopts)
+- libmodbus by Stéphane Raimbault (https://github.com/stephane/libmodbus)

libs/CMakeLists.txt

@@ -1,12 +1,12 @@
 
 # ---------------------------------------- subdirectories --------------------------------------------------------------
 # ======================================================================================================================
-
-
+include(../modbus.cmake)
+target_link_libraries(${Target} PRIVATE modbus)
 
 # ---------------------------------------- link libraries --------------------------------------------------------------
 # ======================================================================================================================
+target_link_libraries(${Target} PRIVATE rt)
 
-
-# ---------------------------------------- utils lib -------------------------------------------------------------------
-# ======================================================================================================================
+add_subdirectory(cxxopts EXCLUDE_FROM_ALL)
+target_link_libraries(${Target} PRIVATE cxxopts)

libs/cxxopts

@@ -0,0 +1,31 @@
+#
+# Builds the modbus library
+#
+# Outputs the following target:
+#   modbus
+#
+include(ExternalProject)
+set(MODBUS_DIR ${CMAKE_CURRENT_SOURCE_DIR}/libmodbus)
+set(MODBUS_BIN ${CMAKE_CURRENT_BINARY_DIR}/libmodbus)
+set(MODBUS_STATIC_LIB ${MODBUS_BIN}/lib/libmodbus.a)
+set(MODBUS_INCLUDES ${MODBUS_BIN}/include)
+
+file(MAKE_DIRECTORY ${MODBUS_INCLUDES})
+
+ExternalProject_Add(
+        libmodbus
+        PREFIX ${MODBUS_BIN}
+        SOURCE_DIR ${MODBUS_DIR}
+        DOWNLOAD_COMMAND cd ${MODBUS_DIR} && git clean -dfX && ${MODBUS_DIR}/autogen.sh
+        CONFIGURE_COMMAND ${MODBUS_DIR}/configure --srcdir=${MODBUS_DIR} --prefix=${MODBUS_BIN} --enable-static=yes --disable-shared
+        BUILD_COMMAND make
+        INSTALL_COMMAND make install
+        BUILD_BYPRODUCTS ${MODBUS_STATIC_LIB}
+)
+
+add_library(modbus STATIC IMPORTED GLOBAL)
+
+add_dependencies(modbus libmodbus)
+
+set_target_properties(modbus PROPERTIES IMPORTED_LOCATION ${MODBUS_STATIC_LIB})
+set_target_properties(modbus PROPERTIES INTERFACE_INCLUDE_DIRECTORIES ${MODBUS_INCLUDES})

libs/libmodbus

@@ -2,10 +2,14 @@
 # ======================================================================================================================
 
 target_sources(${Target} PRIVATE main.cpp)
+target_sources(${Target} PRIVATE modbus_shm.cpp)
+target_sources(${Target} PRIVATE Modbus_TCP_Slave.cpp)
 
 
 # ---------------------------------------- header files (*.jpp, *.h, ...) ----------------------------------------------
 # ======================================================================================================================
+target_sources(${Target} PRIVATE modbus_shm.hpp)
+target_sources(${Target} PRIVATE Modbus_TCP_Slave.hpp)
 
 
 

modbus.cmake

@@ -0,0 +1,85 @@
+#include "Modbus_TCP_Slave.hpp"
+
+#include <stdexcept>
+#include <unistd.h>
+
+namespace Modbus {
+namespace TCP {
+
+static constexpr int MAX_REGS = 0x10000;
+
+Slave::Slave(const std::string &ip, unsigned short port, modbus_mapping_t *mapping) {
+    // create modbus object
+    modbus = modbus_new_tcp(ip.c_str(), static_cast<int>(port));
+    if (modbus == nullptr) {
+        const std::string error_msg = modbus_strerror(errno);
+        throw std::runtime_error("failed to create modbus instance: " + error_msg);
+    }
+
+    if (mapping == nullptr) {
+        // create new mapping with the maximum number of registers
+        this->mapping = modbus_mapping_new(MAX_REGS, MAX_REGS, MAX_REGS, MAX_REGS);
+        if (this->mapping == nullptr) {
+            const std::string error_msg = modbus_strerror(errno);
+            modbus_free(modbus);
+            throw std::runtime_error("failed to allocate memory: " + error_msg);
+        }
+        delete_mapping = true;
+    } else {
+        // use the provided mapping object
+        this->mapping  = mapping;
+        delete_mapping = false;
+    }
+
+    // create tcp socket
+    socket = modbus_tcp_listen(modbus, 1);
+    if (socket == -1) {
+        const std::string error_msg = modbus_strerror(errno);
+        throw std::runtime_error("failed to create tcp socket: " + error_msg);
+    }
+}
+
+Slave::~Slave() {
+    if (modbus != nullptr) {
+        modbus_close(modbus);
+        modbus_free(modbus);
+    }
+    if (mapping != nullptr && delete_mapping) modbus_mapping_free(mapping);
+    if (socket != -1) { close(socket); }
+}
+
+void Slave::set_debug(bool debug) {
+    if (modbus_set_debug(modbus, debug)) {
+        const std::string error_msg = modbus_strerror(errno);
+        throw std::runtime_error("failed to enable modbus debugging mode: " + error_msg);
+    }
+}
+
+void Slave::connect_client() {
+    int tmp = modbus_tcp_accept(modbus, &socket);
+    if (tmp < 0) {
+        const std::string error_msg = modbus_strerror(errno);
+        throw std::runtime_error("modbus_tcp_accept failed: " + error_msg);
+    }
+}
+
+bool Slave::handle_request() {
+    // receive modbus request
+    uint8_t query[MODBUS_TCP_MAX_ADU_LENGTH];
+    int     rc = modbus_receive(modbus, query);
+
+    if (rc > 0) {
+        // handle request
+        modbus_reply(modbus, query, rc, mapping);
+    } else if (rc == -1) {
+        if (errno == ECONNRESET) return true;
+
+        const std::string error_msg = modbus_strerror(errno);
+        throw std::runtime_error("modbus_receive failed: " + error_msg + ' ' + std::to_string(errno));
+    }
+
+    return false;
+}
+
+}  // namespace TCP
+}  // namespace Modbus