Added ability to load modules at runtime

(specified by environment variable path).
Added a demo test module as well.

3 files changed, 137 insertions, 2 deletions

diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index 563ffb340..22fbde265 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -22,6 +22,7 @@ SET(libuhd_sources
     device.cpp
     device_addr.cpp
     gain_handler.cpp
+    load_modules.cpp
     metadata.cpp
     simple_device.cpp
     time_spec.cpp
@@ -56,11 +57,29 @@ LIST(APPEND libuhd_sources
 )
 
 ########################################################################
+# Setup defines for module loading
+########################################################################
+INCLUDE(CheckIncludeFileCXX)
+
+CHECK_INCLUDE_FILE_CXX(dlfcn.h HAVE_DLFCN_H)
+CHECK_INCLUDE_FILE_CXX(Winbase.h HAVE_WINBASE_H)
+
+IF(HAVE_DLFCN_H)
+    MESSAGE(STATUS "Module loading supported through dlopen...")
+    ADD_DEFINITIONS(-DHAVE_DLFCN_H)
+ELSEIF(HAVE_WINBASE_H)
+    MESSAGE(STATUS "Module loading supported through LoadLibrary...")
+    ADD_DEFINITIONS(-DHAVE_WINBASE_H)
+ELSE(HAVE_DLFCN_H)
+    MESSAGE(STATUS "Module loading not supported...")
+ENDIF(HAVE_DLFCN_H)
+
+########################################################################
 # Setup libuhd library
 ########################################################################
 ADD_LIBRARY(uhd SHARED ${libuhd_sources})
 
-TARGET_LINK_LIBRARIES(uhd ${Boost_LIBRARIES})
+TARGET_LINK_LIBRARIES(uhd ${Boost_LIBRARIES} ${CMAKE_DL_LIBS})
 
 SET_TARGET_PROPERTIES(uhd PROPERTIES DEFINE_SYMBOL "UHD_DLL_EXPORTS")
 
diff --git a/host/lib/load_modules.cpp b/host/lib/load_modules.cpp
new file mode 100644
index 000000000..700afcd3f
--- /dev/null
+++ b/host/lib/load_modules.cpp
@@ -0,0 +1,117 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#include <uhd/utils.hpp>
+#include <boost/format.hpp>
+#include <boost/foreach.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/filesystem.hpp>
+#include <iostream>
+#include <stdexcept>
+#include <cstdlib>
+
+namespace fs = boost::filesystem;
+
+/***********************************************************************
+ * Module Load Function
+ **********************************************************************/
+#ifdef HAVE_DLFCN_H
+#include <dlfcn.h>
+
+static void load_module(const std::string &file_name){
+    if (dlopen(file_name.c_str(), RTLD_LAZY) == NULL){
+        throw std::runtime_error(str(
+            boost::format("dlopen failed to load \"%s\"") % file_name
+        ));
+    }
+}
+
+#elif HAVE_WINBASE_H
+#include <Winbase.h>
+
+static void load_module(const std::string &file_name){
+    if (LoadLibrary(file_name.c_str()) == NULL){
+        throw std::runtime_error(str(
+            boost::format("LoadLibrary failed to load \"%s\"") % file_name
+        ));
+    }
+}
+
+#else
+
+static void load_module(const std::string &file_name){
+    throw std::runtime_error(str(
+        boost::format("Module loading not supported: Cannot load \"%s\"") % file_name
+    ));
+}
+
+#endif
+
+/***********************************************************************
+ * Load Modules
+ **********************************************************************/
+/*!
+ * Load all modules in a given path.
+ * This will recurse into sub-directories.
+ * Does not throw, prints to std error.
+ * \param path the filesystem path
+ */
+static void load_path(const fs::path &path){
+    if (not fs::exists(path)){
+        std::cerr << boost::format("Module path \"%s\" not found.") % path.file_string() << std::endl;
+        return;
+    }
+
+    //try to load the files in this path
+    if (fs::is_directory(path)){
+        for(
+            fs::directory_iterator dir_itr(path);
+            dir_itr != fs::directory_iterator();
+            ++dir_itr
+        ){
+            load_path(dir_itr->path());
+        }
+        return;
+    }
+
+    //its not a directory, try to load it
+    try{
+        load_module(path.file_string());
+    }
+    catch(const std::exception &err){
+        std::cerr << boost::format("Error: %s") % err.what() << std::endl;
+    }
+}
+
+/*!
+ * Load all the modules given by the module path enviroment variable.
+ * The path variable may be several paths split by path separators.
+ */
+STATIC_BLOCK(load_modules){
+    //get the environment variable module path
+    char *env_module_path = std::getenv("UHD_MODULE_PATH");
+    if (env_module_path == NULL) return;
+
+    //split the path at the path separators
+    std::vector<std::string> module_paths;
+    boost::split(module_paths, env_module_path, boost::is_any_of(":;"));
+
+    //load modules in each path
+    BOOST_FOREACH(const std::string &module_path, module_paths){
+        load_path(fs::system_complete(fs::path(module_path)));
+    }
+}
diff --git a/host/lib/simple_device.cpp b/host/lib/simple_device.cpp
index 045318c6b..ba1966e0d 100644
--- a/host/lib/simple_device.cpp
+++ b/host/lib/simple_device.cpp
@@ -21,7 +21,6 @@
 #include <uhd/props.hpp>
 #include <uhd/types.hpp>
 #include <boost/algorithm/string.hpp>
-#include <boost/algorithm/string/trim.hpp>
 #include <boost/foreach.hpp>
 #include <boost/format.hpp>
 #include <stdexcept>