Added ability to load modules at runtime

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

1 files changed, 117 insertions, 0 deletions

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)));
+    }
+}