phase 2 serial

cmake/SoftbusThirdParty.cmake

@@ -73,6 +73,45 @@ else()
     set(SOFTBUS_HAS_OPCUA OFF)
 endif()
 
+# libmodbus (edge RTU/TCP): system pkg-config first, else third_party vendor
+set(SOFTBUS_HAS_LIBMODBUS OFF)
+set(SOFTBUS_LIBMODBUS_VENDOR OFF)
+
+option(SOFTBUS_FORCE_VENDOR_LIBMODBUS
+    "Always build libmodbus from third_party/libmodbus" OFF)
+
+if(NOT SOFTBUS_FORCE_VENDOR_LIBMODBUS)
+    find_package(PkgConfig QUIET)
+    if(PkgConfig_FOUND)
+        pkg_check_modules(LIBMODBUS QUIET libmodbus)
+    endif()
+endif()
+
+if(LIBMODBUS_FOUND AND NOT SOFTBUS_FORCE_VENDOR_LIBMODBUS)
+    set(SOFTBUS_HAS_LIBMODBUS ON)
+    add_library(libmodbus_iface INTERFACE)
+    target_include_directories(libmodbus_iface INTERFACE ${LIBMODBUS_INCLUDE_DIRS})
+    target_link_libraries(libmodbus_iface INTERFACE ${LIBMODBUS_LIBRARIES})
+    message(STATUS "libmodbus: using system package (pkg-config)")
+else()
+    add_subdirectory("${CMAKE_CURRENT_LIST_DIR}/libmodbus")
+    if(NOT SOFTBUS_HAS_LIBMODBUS)
+        message(STATUS "libmodbus not available; softbus_edge uses simulated Modbus I/O")
+    endif()
+endif()
+
+function(softbus_apply_libmodbus target)
+    if(SOFTBUS_HAS_LIBMODBUS)
+        target_compile_definitions(${target} PRIVATE SOFTBUS_HAS_LIBMODBUS=1)
+        target_link_libraries(${target} PRIVATE libmodbus_iface)
+        if(SOFTBUS_LIBMODBUS_VENDOR)
+            target_compile_definitions(${target} PRIVATE SOFTBUS_LIBMODBUS_VENDOR=1)
+        endif()
+    else()
+        target_compile_definitions(${target} PRIVATE SOFTBUS_HAS_LIBMODBUS=0)
+    endif()
+endfunction()
+
 function(softbus_apply_open62541 target)
     if(SOFTBUS_HAS_OPCUA)
         target_compile_definitions(${target} PRIVATE SOFTBUS_HAS_OPCUA=1)