A posix (dlopen et al) implementation of the dynamic module loader

abstraction.

src/jrd/os/posix/mod_loader.cpp

@@ -0,0 +1,75 @@
+/*
+ *  mod_loader.cpp
+ *
+ */
+
+#include "../jrd/os/mod_loader.h"
+#include "common.h"
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dlfcn.h>
+
+/// This is the POSIX (dlopen) implementation of the mod_loader abstraction.
+
+class DlfcnModule : public ModuleLoader::Module
+{
+public:
+	DlfcnModule(void *m) : module(m) {}
+	~DlfcnModule();
+	void *findSymbol(const Firebird::string&);
+	
+private:
+	void *module;
+};
+
+bool ModuleLoader::isLoadableModule(const Firebird::string& module)
+{
+	struct stat sb;
+	if (-1 == stat(module.c_str(), &sb))
+		return false;
+	if ( ! (sb.st_mode & S_IFREG) )		// Make sure it is a plain file
+		return false;
+	if ( -1 == access(module.c_str(), R_OK | X_OK))
+		return false;
+	return true;
+}
+
+void ModuleLoader::doctorModuleExtention(Firebird::string& name)
+{
+	Firebird::string::size_type pos = name.rfind(".so");
+	if (pos != Firebird::string::npos && pos == name.length() - 3)
+		return;		// No doctoring necessary
+	name += ".so";
+}
+
+ModuleLoader::Module *ModuleLoader::loadModule(const Firebird::string& modPath)
+{
+	void *module;
+	
+	module = dlopen(modPath.c_str(), RTLD_LAZY);
+	if (module == NULL)
+		return 0;
+	
+	return new(*getDefaultMemoryPool()) DlfcnModule(module);
+}
+
+DlfcnModule::~DlfcnModule()
+{
+	if (module)
+		dlclose(module);
+}
+
+void *DlfcnModule::findSymbol(const Firebird::string& symName)
+{
+	void *result;  
+
+	result = dlsym(module, symName.c_str());
+	if (result == NULL)
+	{
+		Firebird::string newSym = '_' + symName;
+
+		result = dlsym(module, newSym.c_str());
+	}
+	return result;
+}