build: Check if libdl exists in the system

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>

src/CMakeLists.txt

@@ -8,10 +8,18 @@ set(UHTTPD_VERSION_PATCH 1)
 
 # Check the third party Libraries
 find_package(Libev REQUIRED)
+find_library(LIBDL dl)
 
 include_directories(${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/buffer ${CMAKE_CURRENT_BINARY_DIR} ${LIBEV_INCLUDE_DIR})
 
-set(EXTRA_LIBS ${LIBEV_LIBRARY} dl m)
+set(EXTRA_LIBS ${LIBEV_LIBRARY} m)
+
+if(NOT ${LIBDL} STREQUAL "LIBDL-NOTFOUND")
+    message(STATUS "Found Libdl: ${LIBDL}")
+    list(APPEND EXTRA_LIBS ${LIBDL})
+    add_definitions(-DHAVE_DLOPEN)
+endif()
+
 set(SOURCE_FILES uhttpd.c log.c connection.c buffer/buffer.c http-parser/http_parser.c ssl.c)
 
 set(UHTTPD_SSL_SUPPORT_CONFIG 1)
@@ -100,7 +108,9 @@ target_link_libraries(uhttpd_s ${EXTRA_LIBS})
 # configure a header file to pass some of the CMake settings to the source code
 configure_file(${CMAKE_CURRENT_SOURCE_DIR}/config.h.in ${CMAKE_CURRENT_BINARY_DIR}/config.h)
 
-add_subdirectory(plugins)
+if(NOT ${LIBDL} STREQUAL "LIBDL-NOTFOUND")
+    add_subdirectory(plugins)
+endif()
 
 install(
     FILES

src/uhttpd.c

@@ -26,9 +26,11 @@
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
-#include <dlfcn.h>
 #include <arpa/inet.h>
 #include <sys/socket.h>
+#ifdef HAVE_DLOPEN
+#include <dlfcn.h>
+#endif
 
 #include "uhttpd.h"
 #include "utils.h"
@@ -113,6 +115,7 @@ static int uh_server_ssl_init(struct uh_server *srv, const char *cert, const cha
 
 static int uh_load_plugin(struct uh_server *srv, const char *path)
 {
+#ifdef HAVE_DLOPEN
     struct uh_plugin *p;
     void *dlh;
 
@@ -143,6 +146,10 @@ static int uh_load_plugin(struct uh_server *srv, const char *path)
     srv->plugins = p;
 
     return 0;
+#else
+    uh_log_err("Not support plugin\n");
+    return -1;
+#endif
 }
 
 int uh_server_init(struct uh_server *srv, struct ev_loop *loop, const char *host, int port)