Merge pull request #10 from NikolasK-source/main

Release 0.2.1

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

CMakeLists.txt

@@ -4,7 +4,7 @@ cmake_minimum_required(VERSION 3.13.4 FATAL_ERROR)
 # ======================================================================================================================
 
 # project
-project(Modbus_RTU_client_shm LANGUAGES CXX VERSION 0.2.0)
+project(Modbus_RTU_client_shm LANGUAGES CXX VERSION 0.2.1)
 
 # settings
 set(Target "modbus-rtu-client-shm")    # Executable name (without file extension!)

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

@@ -29,6 +29,17 @@ static void sig_term_handler(int) {
     terminate = true;
 }
 
+constexpr std::array<int, 10> TERM_SIGNALS = {SIGINT,
+                                              SIGTERM,
+                                              SIGHUP,
+                                              SIGIO,  // should not happen
+                                              SIGPIPE,
+                                              SIGPOLL,  // should not happen
+                                              SIGPROF,  // should not happen
+                                              SIGUSR1,
+                                              SIGUSR2,
+                                              SIGVTALRM};
+
 /*! \brief main function
  *
  * @param argc number of arguments
@@ -47,16 +58,24 @@ int main(int argc, char **argv) {
     auto euid = geteuid();
     if (!euid) std::cerr << "!!!! WARNING: You should not execute this program with root privileges !!!!" << std::endl;
 
+#ifdef COMPILER_CLANG
+#    pragma clang diagnostic push
+#    pragma clang diagnostic ignored "-Wdisabled-macro-expansion"
+#endif
     // establish signal handler
-    if (signal(SIGINT, sig_term_handler) || signal(SIGTERM, sig_term_handler)) {
-        perror("Failed to establish signal handler");
-        return EX_OSERR;
-    }
-
-    if (signal(SIGALRM, [](int) { exit(EX_OK); })) {
-        perror("Failed to establish signal handler");
-        return EX_OSERR;
+    struct sigaction term_sa;
+    term_sa.sa_handler = sig_term_handler;
+    term_sa.sa_flags   = SA_RESTART;
+    sigemptyset(&term_sa.sa_mask);
+    for (const auto SIGNO : TERM_SIGNALS) {
+        if (sigaction(SIGNO, &term_sa, nullptr)) {
+            perror("Failed to establish signal handler");
+            return EX_OSERR;
+        }
     }
+#ifdef COMPILER_CLANG
+#    pragma clang diagnostic pop
+#endif
 
     // all command line arguments
     options.add_options()("d,device", "mandatory: serial device", cxxopts::value<std::string>());

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
      *