cmake: add SDL_LIBUDEV_SHARED option

CMakeLists.txt

@@ -400,7 +400,8 @@ dep_option(SDL_HIDAPI_LIBUSB       "Use libusb for low level joystick drivers" O
 dep_option(SDL_HIDAPI_LIBUSB_SHARED "Dynamically load libusb support" ON "SDL_HIDAPI_LIBUSB;SDL_DEPS_SHARED" OFF)
 dep_option(SDL_HIDAPI_JOYSTICK     "Use HIDAPI for low level joystick drivers" ON SDL_HIDAPI OFF)
 dep_option(SDL_VIRTUAL_JOYSTICK    "Enable the virtual-joystick driver" ON SDL_HIDAPI OFF)
-set_option(SDL_LIBUDEV             "Enable libudev support" ON)
+dep_option(SDL_LIBUDEV             "Enable libudev support" ON ${UNIX_SYS} OFF)
+dep_option(SDL_LIBUDEV_SHARED      "Dynamically load libudev support" ON "SDL_LIBUDEV;SDL_DEPS_SHARED" OFF)
 set_option(SDL_ASAN                "Use AddressSanitizer to detect memory errors" OFF)
 set_option(SDL_CCACHE              "Use Ccache to speed up build" OFF)
 set_option(SDL_CLANG_TIDY          "Run clang-tidy static analysis" OFF)

cmake/sdlchecks.cmake

@@ -1408,14 +1408,27 @@ macro(CheckKMSDRM)
 endmacro()
 
 macro(CheckLibUDev)
+  set(HAVE_LIBUDEV_H FALSE)
+  set(HAVE_LIBUDEV FALSE)
+  set(HAVE_LIBUDEV_SHARED OFF)
   if(SDL_LIBUDEV)
     check_include_file("libudev.h" HAVE_LIBUDEV_HEADER)
     if(HAVE_LIBUDEV_HEADER)
       set(HAVE_LIBUDEV_H TRUE)
-      FindLibraryAndSONAME(udev)
-      if(UDEV_LIB_SONAME)
-        set(SDL_UDEV_DYNAMIC "\"${UDEV_LIB_SONAME}\"")
-        set(HAVE_LIBUDEV TRUE)
+      set(HAVE_LIBUDEV TRUE)
+      if(SDL_LIBUDEV_SHARED)
+        if(NOT HAVE_SDL_LOADSO)
+          message(WARNING "You must have SDL_LoadObject() support for dynamic libudev support")
+        else()
+          FindLibraryAndSONAME(udev)
+          if(UDEV_LIB_SONAME)
+            set(SDL_UDEV_DYNAMIC "\"${UDEV_LIB_SONAME}\"")
+            set(HAVE_LIBUDEV_SHARED TRUE)
+          endif()
+        endif()
+      endif()
+      if(NOT HAVE_LIBUDEV_SHARED)
+        sdl_link_dependency(udev PRIVATE LIBS udev)
       endif()
     endif()
   endif()

src/core/linux/SDL_udev.c

@@ -41,10 +41,8 @@
 static const char *SDL_UDEV_LIBS[] = { SDL_UDEV_FALLBACK_LIBS };
 
 #ifdef SDL_UDEV_DYNAMIC
+
 #define SDL_UDEV_DLNOTE_LIBS SDL_UDEV_DYNAMIC, SDL_UDEV_FALLBACK_LIBS
-#else
-#define SDL_UDEV_DLNOTE_LIBS SDL_UDEV_FALLBACK_LIBS
-#endif
 
 SDL_ELF_NOTE_DLOPEN(
     "events-udev",
@@ -52,17 +50,21 @@ SDL_ELF_NOTE_DLOPEN(
     SDL_ELF_NOTE_DLOPEN_PRIORITY_RECOMMENDED,
     SDL_UDEV_DLNOTE_LIBS
 )
+#endif
 
 static SDL_UDEV_PrivateData *_this = NULL;
 
+#ifdef SDL_UDEV_DYNAMIC
 static bool SDL_UDEV_load_sym(const char *fn, void **addr);
 static bool SDL_UDEV_load_syms(void);
+#endif
 static bool SDL_UDEV_hotplug_update_available(void);
 static void get_caps(struct udev_device *dev, struct udev_device *pdev, const char *attr, unsigned long *bitmask, size_t bitmask_len);
 static int guess_device_class(struct udev_device *dev);
 static int device_class(struct udev_device *dev);
 static void device_event(SDL_UDEV_deviceevent type, struct udev_device *dev);
 
+#ifdef SDL_UDEV_DYNAMIC
 static bool SDL_UDEV_load_sym(const char *fn, void **addr)
 {
     *addr = SDL_LoadFunction(_this->udev_handle, fn);
@@ -73,9 +75,12 @@ static bool SDL_UDEV_load_sym(const char *fn, void **addr)
 
     return true;
 }
+#endif
 
 static bool SDL_UDEV_load_syms(void)
 {
+
+#ifdef SDL_UDEV_DYNAMIC
 /* cast funcs to char* first, to please GCC's strict aliasing rules. */
 #define SDL_UDEV_SYM(x)                                          \
     if (!SDL_UDEV_load_sym(#x, (void **)(char *)&_this->syms.x)) \
@@ -83,6 +88,13 @@ static bool SDL_UDEV_load_syms(void)
 
 #define SDL_UDEV_SYM_OPTIONAL(x)                                 \
     SDL_UDEV_load_sym(#x, (void **)(char *)&_this->syms.x);
+#else
+#define SDL_UDEV_SYM(x)                                          \
+    _this->syms.x = x;
+
+#define SDL_UDEV_SYM_OPTIONAL(x)                                 \
+    _this->syms.x = x;
+#endif
 
     SDL_UDEV_SYM(udev_device_get_action);
     SDL_UDEV_SYM(udev_device_get_devnode);

src/core/linux/SDL_udev.h

@@ -64,13 +64,13 @@ typedef struct SDL_UDEV_Symbols
     const char *(*udev_device_get_property_value)(struct udev_device *, const char *);
     const char *(*udev_device_get_sysattr_value)(struct udev_device *udev_device, const char *sysattr);
     struct udev_device *(*udev_device_new_from_syspath)(struct udev *, const char *);
-    void (*udev_device_unref)(struct udev_device *);
+    struct udev_device *(*udev_device_unref)(struct udev_device *);
     int (*udev_enumerate_add_match_property)(struct udev_enumerate *, const char *, const char *);
     int (*udev_enumerate_add_match_subsystem)(struct udev_enumerate *, const char *);
     struct udev_list_entry *(*udev_enumerate_get_list_entry)(struct udev_enumerate *);
     struct udev_enumerate *(*udev_enumerate_new)(struct udev *);
     int (*udev_enumerate_scan_devices)(struct udev_enumerate *);
-    void (*udev_enumerate_unref)(struct udev_enumerate *);
+    struct udev_enumerate *(*udev_enumerate_unref)(struct udev_enumerate *);
     const char *(*udev_list_entry_get_name)(struct udev_list_entry *);
     const char *(*udev_list_entry_get_value)(struct udev_list_entry *);
     struct udev_list_entry *(*udev_list_entry_get_next)(struct udev_list_entry *);
@@ -79,9 +79,9 @@ typedef struct SDL_UDEV_Symbols
     int (*udev_monitor_get_fd)(struct udev_monitor *);
     struct udev_monitor *(*udev_monitor_new_from_netlink)(struct udev *, const char *);
     struct udev_device *(*udev_monitor_receive_device)(struct udev_monitor *);
-    void (*udev_monitor_unref)(struct udev_monitor *);
+    struct udev_monitor *(*udev_monitor_unref)(struct udev_monitor *);
     struct udev *(*udev_new)(void);
-    void (*udev_unref)(struct udev *);
+    struct udev *(*udev_unref)(struct udev *);
     struct udev_device *(*udev_device_new_from_devnum)(struct udev *udev, char type, dev_t devnum);
     dev_t (*udev_device_get_devnum)(struct udev_device *udev_device);