Merge pull request #16 from NikolasK-source/main

Release 1.2.1

Author: NikolasK-source

.gitmodules

@@ -4,3 +4,6 @@
 [submodule "libs/libmodbus"]
 	path = libs/libmodbus
 	url = https://github.com/stephane/libmodbus
+[submodule "libs/cxxshm"]
+	path = libs/cxxshm
+	url = https://github.com/NikolasK-source/cxxshm.git

libs/CMakeLists.txt

@@ -10,3 +10,6 @@ target_link_libraries(${Target} PRIVATE rt)
 
 add_subdirectory(cxxopts EXCLUDE_FROM_ALL)
 target_link_libraries(${Target} PRIVATE cxxopts)
+
+add_subdirectory(cxxshm EXCLUDE_FROM_ALL)
+target_link_libraries(${Target} PRIVATE cxxshm)

libs/cxxshm

@@ -560,4 +560,29 @@ void print_licenses(std::ostream &o) {
     o << "      Ty Coon, President of Vice" << std::endl;
     o << std::endl;
     o << "    That's all there is to it!" << std::endl;
+    o << std::endl;
+    o << std::endl;
+    o << "cxxshm Library (https://github.com/NikolasK-source/cxxshm)" << std::endl;
+    o << std::endl;
+    o << "    MIT License" << std::endl;
+    o << std::endl;
+    o << "    Copyright (c) 2022 Nikolas Koesling" << std::endl;
+    o << std::endl;
+    o << "    Permission is hereby granted, free of charge, to any person obtaining a copy" << std::endl;
+    o << "    of this software and associated documentation files (the \"Software\"), to deal" << std::endl;
+    o << "    in the Software without restriction, including without limitation the rights" << std::endl;
+    o << "    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell" << std::endl;
+    o << "    copies of the Software, and to permit persons to whom the Software is" << std::endl;
+    o << "    furnished to do so, subject to the following conditions:" << std::endl;
+    o << std::endl;
+    o << "    The above copyright notice and this permission notice shall be included in all" << std::endl;
+    o << "    copies or substantial portions of the Software." << std::endl;
+    o << std::endl;
+    o << "    THE SOFTWARE IS PROVIDED \"AS IS\", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR" << std::endl;
+    o << "    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY," << std::endl;
+    o << "    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE" << std::endl;
+    o << "    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER" << std::endl;
+    o << "    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM," << std::endl;
+    o << "    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE" << std::endl;
+    o << "    SOFTWARE." << std::endl;
 }

src/license.cpp

@@ -189,6 +189,7 @@ int main(int argc, char **argv) {
         std::cout << "This application uses the following libraries:" << std::endl;
         std::cout << "  - cxxopts by jarro2783 (https://github.com/jarro2783/cxxopts)" << std::endl;
         std::cout << "  - libmodbus by Stéphane Raimbault (https://github.com/stephane/libmodbus)" << std::endl;
+        std::cout << "  - cxxshm (https://github.com/NikolasK-source/cxxshm)" << std::endl;
         return EX_OK;
     }
 

src/main.cpp

@@ -35,71 +35,17 @@ Shm_Mapping::Shm_Mapping(std::size_t        nb_bits,
     mapping.nb_registers       = static_cast<int>(nb_registers);
     mapping.nb_input_registers = static_cast<int>(nb_input_registers);
 
-    // calculate shm object size
-    shm_data[DO].size = nb_bits;
-    shm_data[DI].size = nb_input_bits;
-    shm_data[AO].size = nb_registers * 2;
-    shm_data[AI].size = nb_input_registers * 2;
-
-    // create shm object names
-    shm_data[DO].name = prefix + "DO";
-    shm_data[DI].name = prefix + "DI";
-    shm_data[AO].name = prefix + "AO";
-    shm_data[AI].name = prefix + "AI";
-
-    // create and map shm objects
-    for (std::size_t i = 0; i < reg_index_t::REG_COUNT; ++i) {
-        auto &shm = shm_data[i];
-
-        int flags = O_RDWR | O_CREAT;
-        if (!force) flags |= O_EXCL;
-
-        // create shm object
-        shm.fd = shm_open(shm.name.c_str(), flags, 0660);
-        if (shm.fd < 0) {
-            throw std::system_error(
-                    errno, std::generic_category(), "Failed to create shared memory '" + shm.name + '\'');
-        }
-
-        // set size of shm object
-        if (ftruncate(shm.fd, static_cast<__off_t>(shm.size))) {
-            throw std::system_error(
-                    errno, std::generic_category(), "Failed to resize shared memory '" + shm.name + '\'');
-        }
-
-        // map shm object
-        shm.addr = mmap(nullptr, shm.size, PROT_WRITE | PROT_READ, MAP_SHARED, shm.fd, 0);
-        if (shm.addr == nullptr && shm.addr == MAP_FAILED) {
-            shm.addr = nullptr;
-            throw std::system_error(errno, std::generic_category(), "Failed to map shared memory '" + shm.name + '\'');
-        }
-    }
+    // create shm objects
+    shm_data[DO] = std::make_unique<cxxshm::SharedMemory>(prefix + "DO", nb_bits, false, !force);
+    shm_data[DI] = std::make_unique<cxxshm::SharedMemory>(prefix + "DI", nb_input_bits, false, !force);
+    shm_data[AO] = std::make_unique<cxxshm::SharedMemory>(prefix + "AO", 2 * nb_registers, false, !force);
+    shm_data[AI] = std::make_unique<cxxshm::SharedMemory>(prefix + "AI", nb_input_registers, false, !force);
 
     // set shm objects as modbus register storage
-    mapping.tab_bits            = static_cast<uint8_t *>(shm_data[DO].addr);
-    mapping.tab_input_bits      = static_cast<uint8_t *>(shm_data[DI].addr);
-    mapping.tab_registers       = static_cast<uint16_t *>(shm_data[AO].addr);
-    mapping.tab_input_registers = static_cast<uint16_t *>(shm_data[AI].addr);
-}
-
-Shm_Mapping::~Shm_Mapping() {
-    // unmap and delete shm objects
-    for (std::size_t i = 0; i < reg_index_t::REG_COUNT; ++i) {
-        auto &shm = shm_data[i];
-        if (shm.addr) {
-            if (munmap(shm.addr, shm.size)) { perror(("Failed to unmap shared memory '" + shm.name + '\'').c_str()); }
-        }
-
-        if (shm.fd != -1) {
-            if (close(shm.fd)) {
-                perror(("Failed to close shared memory file descriptor '" + shm.name + '\'').c_str());
-            }
-
-            if (shm_unlink(shm.name.c_str())) {
-                perror(("Failed to unlink shared memory '" + shm.name + '\'').c_str());
-            }
-        }
-    }
+    mapping.tab_bits            = static_cast<uint8_t *>(shm_data[DO]->get_addr());
+    mapping.tab_input_bits      = static_cast<uint8_t *>(shm_data[DI]->get_addr());
+    mapping.tab_registers       = static_cast<uint16_t *>(shm_data[AO]->get_addr());
+    mapping.tab_input_registers = static_cast<uint16_t *>(shm_data[AI]->get_addr());
 }
 
 }  // namespace shm

src/modbus_shm.cpp

@@ -5,9 +5,11 @@
 
 #pragma once
 
+#include "cxxshm.hpp"
 #include "modbus/modbus.h"
 #include <array>
 #include <cstddef>
+#include <memory>
 #include <string>
 
 namespace Modbus {
@@ -17,7 +19,7 @@ namespace shm {
  *
  * All required shm objects are created on construction and and deleted on destruction.
  */
-class Shm_Mapping {
+class Shm_Mapping final {
 private:
     enum reg_index_t : std::size_t { DO, DI, AO, AI, REG_COUNT };
 
@@ -33,7 +35,7 @@ class Shm_Mapping {
     modbus_mapping_t mapping {};
 
     //! info for all shared memory objects
-    std::array<shm_data_t, reg_index_t::REG_COUNT> shm_data;
+    std::array<std::unique_ptr<cxxshm::SharedMemory>, reg_index_t::REG_COUNT> shm_data;
 
 public:
     /*! \brief creates a new modbus_mapping_t. Like modbus_mapping_new(), but creates shared memory objects to store its
@@ -59,7 +61,7 @@ class Shm_Mapping {
                 const std::string &shm_name_prefix = "modbus_",
                 bool               force           = false);
 
-    ~Shm_Mapping();
+    ~Shm_Mapping() = default;
 
     /*! \brief get a pointer to the created modbus_mapping_t object
      *