cleaning up moduleloader - incomplete

master
Chris Punches 2025-02-23 20:22:35 -05:00
parent 496cc9d4e6
commit d320abf1ca
4 changed files with 153 additions and 65 deletions

View File

@ -7,6 +7,10 @@ enum class DPMError {
PATH_NOT_DIRECTORY,
PERMISSION_DENIED,
MODULE_NOT_FOUND,
MODULE_NOT_LOADED,
MODULE_LOAD_FAILED,
INVALID_MODULE
INVALID_MODULE,
SYMBOL_NOT_FOUND,
SYMBOL_EXECUTION_FAILED,
UNDEFINED_ERROR
};

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@ -52,96 +52,174 @@ DPMError ModuleLoader::load_module(const std::string& module_name, void*& module
return DPMError::MODULE_LOAD_FAILED;
}
dlerror();
return DPMError::SUCCESS;
std::vector<std::string> missing_symbols;
DPMError validate_error = validate_module_interface(module_handle, missing_symbols);
if ( validate_error != DPMError::SUCCESS ) {
dlclose(module_handle);
return validate_error;
}
return validate_error;
}
DPMError ModuleLoader::execute_module(const std::string& module_name, const std::string& command) const
{
void* module_handle;
DPMError load_error = load_module(module_name, module_handle);
// declare a module_handle
void * module_handle;
if (load_error != DPMError::SUCCESS) {
// attempt to load the module
DPMError load_error = load_module( module_name, module_handle );
if ( load_error != DPMError::SUCCESS ) {
return load_error;
}
std::vector<std::string> missing_symbols;
DPMError validate_error = validate_module_interface(module_handle, missing_symbols);
if (validate_error != DPMError::SUCCESS) {
dlclose(module_handle);
return DPMError::INVALID_MODULE;
// Clear any previous error state and handle any residual failure
const char* pre_error = dlerror();
if ( pre_error != nullptr ) {
dlclose( module_handle );
return DPMError::UNDEFINED_ERROR;
}
using ExecuteFn = int (*)(const char*, int, char**);
ExecuteFn execute_fn = (ExecuteFn)dlsym(module_handle, "dpm_module_execute");
// declare a function pointer type to hold the module symbol to execute
typedef int (*ExecuteFn) ( const char*, int, char** );
const char* error = dlerror();
DPMError result = DPMError::SUCCESS;
// populate that void pointer to the execute symbol in the module with
ExecuteFn execute_fn = (ExecuteFn) dlsym( module_handle, "dpm_module_execute" );
if (error != nullptr) {
result = DPMError::MODULE_LOAD_FAILED;
} else {
execute_fn(command.c_str(), 0, nullptr);
// do basic error handling to detect if the symbol look up was successful
const char * dlsym_error = dlerror();
if ( dlsym_error != nullptr ) {
dlclose( module_handle );
return DPMError::SYMBOL_NOT_FOUND;
}
dlclose(module_handle);
return result;
// check if the void pointer was populated
if ( execute_fn == nullptr ) {
dlclose( module_handle );
return DPMError::SYMBOL_NOT_FOUND;
}
// execute the symbol that was loaded and supply the command string being routed from DPM
int exec_error = execute_fn( command.c_str(), 0, nullptr );
// irregardless of result, this is the time to close the module handle
dlclose( module_handle );
// if the result of execution was not 0, return an error
if ( exec_error != 0 ) {
return DPMError::SYMBOL_EXECUTION_FAILED;
}
// if we made it here, assume it was successful
return DPMError::SUCCESS;
}
DPMError ModuleLoader::get_module_version(void* module_handle, std::string& version) const
DPMError ModuleLoader::get_module_version( void * module_handle, std::string& version ) const
{
if (!module_handle) {
// validate that the module is even loaded
if ( !module_handle ) {
version = "DPM ERROR";
return DPMError::MODULE_NOT_LOADED;
}
// Clear any previous error state and handle any residual failure
const char* pre_error = dlerror();
if ( pre_error != nullptr ) {
version = pre_error;
return DPMError::UNDEFINED_ERROR;
}
// declare a function pointer type to hold the module symbol to execute
typedef const char * (* VersionFn)();
// populate that void pointer to execute the symbol in the module with
VersionFn version_fn = (VersionFn) dlsym( module_handle, "dpm_module_get_version" );
// Check for errors from dlsym
const char* error = dlerror();
if (error != nullptr) {
version = error;
return DPMError::SYMBOL_NOT_FOUND;
}
// check if the void pointer was populated
if ( version_fn == nullptr ) {
version = "ERROR";
return DPMError::SYMBOL_NOT_FOUND;
}
// execute the loaded symbol
const char * ver = version_fn();
// check the return, and throw an error if it's a null value
if ( ver == nullptr ) {
version = "MODULE ERROR";
return DPMError::INVALID_MODULE;
}
dlerror();
using GetVersionFn = const char* (*)();
GetVersionFn get_version = (GetVersionFn)dlsym(module_handle, "dpm_module_get_version");
const char* error = dlerror();
if (error != nullptr) {
version = "unknown";
return DPMError::MODULE_LOAD_FAILED;
}
const char* ver = get_version();
version = ver ? ver : "unknown";
// if you made it here, assume success
return DPMError::SUCCESS;
}
DPMError ModuleLoader::get_module_description(void* module_handle, std::string& description) const
{
// validate that the module is even loaded
if (!module_handle) {
description = "DPM ERROR";
return DPMError::MODULE_NOT_LOADED;
}
// Clear any previous error state and handle any residual failure
const char* pre_error = dlerror();
if ( pre_error != nullptr ) {
version = pre_error;
return DPMError::UNDEFINED_ERROR;
}
// declare a function pointer type to hold the module symbol to execute
typedef const char * (* DescriptionFn)();
// populate that void pointer to execute the symbol in the module with
DescriptionFn description_fn = (DescriptionFn) dlsym( module_handle, "dpm_get_description" );
// check for errors from dlsym
const char* error = dlerror();
if ( error != nullptr ) {
description = "ERROR";
return DPMError::SYMBOL_NOT_FOUND;
}
// check if the void pointer was populated
if ( description_fn == nullptr ) {
description = "ERROR";
return DPMError::INVALID_MODULE;
}
dlerror();
// execute the loaded symbol
const char* desc = description_fn();
using GetDescriptionFn = const char* (*)();
GetDescriptionFn get_description = (GetDescriptionFn)dlsym(module_handle, "dpm_get_description");
const char* error = dlerror();
if (error != nullptr) {
description = "unknown";
return DPMError::MODULE_LOAD_FAILED;
// check the return, and throw an error if it's a null value
if ( desc == nullptr ) {
description = "MODULE ERROR";
return DPMError::INVALID_MODULE;
}
const char* desc = get_description();
description = desc ? desc : "unknown";
// if you made it here, assume success
return DPMError::SUCCESS;
}
DPMError ModuleLoader::validate_module_interface(void* module_handle, std::vector<std::string>& missing_symbols) const
{
if (!module_handle) {
return DPMError::INVALID_MODULE;
// validate that the module is even loaded
if ( !module_handle ) {
return DPMError::MODULE_NOT_LOADED;
}
// ensure our starting point of missing symbols is empty
missing_symbols.clear();
// get the size of the loop (should be equal to the number of required symbols)
size_t num_symbols = module_interface::required_symbols.size();
for (size_t i = 0; i < num_symbols; i++) {
dlerror();

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@ -46,5 +46,5 @@ int main( int argc, char* argv[] )
DPMError execute_error = loader.execute_module(args.module_name, args.command);
// pair result with a message and exit with the appropriate error code
return print_error(execute_error, args.module_name, args.module_path);
return print_error( execute_error, args.module_name, args.module_path );
}

View File

@ -62,9 +62,9 @@ int main_list_modules(const ModuleLoader& loader)
}
std::vector<std::string> valid_modules;
for (const auto& module : modules) {
for (int i = 0; i < modules.size(); i++) {
void* handle;
DPMError load_error = loader.load_module(module, handle);
DPMError load_error = loader.load_module(modules[i], handle);
if (load_error != DPMError::SUCCESS) {
continue;
}
@ -72,7 +72,7 @@ int main_list_modules(const ModuleLoader& loader)
std::vector<std::string> missing_symbols;
DPMError validate_error = loader.validate_module_interface(handle, missing_symbols);
if (validate_error == DPMError::SUCCESS) {
valid_modules.push_back(module);
valid_modules.push_back(modules[i]);
}
dlclose(handle);
}
@ -84,12 +84,12 @@ int main_list_modules(const ModuleLoader& loader)
size_t max_name_length = 0;
size_t max_version_length = 0;
for (const auto& module : valid_modules) {
for (int i = 0; i < valid_modules.size(); i++) {
void* module_handle;
std::string version;
max_name_length = std::max(max_name_length, module.length());
max_name_length = std::max(max_name_length, valid_modules[i].length());
DPMError load_error = loader.load_module(module, module_handle);
DPMError load_error = loader.load_module(valid_modules[i], module_handle);
if (load_error == DPMError::SUCCESS) {
DPMError version_error = loader.get_module_version(module_handle, version);
if (version_error == DPMError::SUCCESS) {
@ -101,24 +101,24 @@ int main_list_modules(const ModuleLoader& loader)
const int column_spacing = 4;
std::cout << "Available modules in '" << path << "':" << std::endl << std::endl;
std::cout << "\nAvailable modules in '" << path << "':" << std::endl << std::endl;
std::cout << std::left << std::setw(max_name_length + column_spacing) << "MODULE"
<< std::setw(max_version_length + column_spacing) << "VERSION"
<< "DESCRIPTION" << std::endl;
for (const auto& module_name : valid_modules) {
for (int i = 0; i < valid_modules.size(); i++) {
void* module_handle;
std::string version = "unknown";
std::string description = "unknown";
DPMError load_error = loader.load_module(module_name, module_handle);
DPMError load_error = loader.load_module(valid_modules[i], module_handle);
if (load_error == DPMError::SUCCESS) {
DPMError version_error = loader.get_module_version(module_handle, version);
DPMError desc_error = loader.get_module_description(module_handle, description);
dlclose(module_handle);
}
std::cout << std::left << std::setw(max_name_length + column_spacing) << module_name
std::cout << std::left << std::setw(max_name_length + column_spacing) << valid_modules[i]
<< std::setw(max_version_length + column_spacing) << version
<< description << std::endl;
}
@ -143,14 +143,14 @@ CommandArgs parse_args(int argc, char* argv[])
switch (opt) {
case 'm':
args.module_path = optarg;
break;
break;
case 'h':
std::cout << "Usage: dpm [options] [module-name] [module args...]\n\n"
<< "Options:\n\n"
<< " -m, --module-path PATH Path to DPM modules\n"
<< " -h, --help Show this help message\n"
<< "\nIf no module is specified, available modules will be listed.\n\n";
exit(0);
<< "Options:\n\n"
<< " -m, --module-path PATH Path to DPM modules\n"
<< " -h, --help Show this help message\n\n"
<< "If no module is specified, available modules will be listed.\n\n";
exit(0);
case '?':
exit(1);
}
@ -192,12 +192,18 @@ int print_error(DPMError error, const std::string& module_name, const std::strin
case DPMError::MODULE_NOT_FOUND:
std::cerr << "Module not found: " << module_name << std::endl;
return 1;
case DPMError::MODULE_NOT_LOADED:
std::cerr << "Attempted to execute module before loading it: " << module_name << std::endl;
return 1;
case DPMError::MODULE_LOAD_FAILED:
std::cerr << "Failed to load module: " << module_name << std::endl;
return 1;
case DPMError::INVALID_MODULE:
std::cerr << "Invalid module format: " << module_name << std::endl;
return 1;
case DPMError::UNDEFINED_ERROR:
std::cerr << "Undefined error occurred with module: " << module_name << std::endl;
return 1;
default:
std::cerr << "Unknown error executing module: " << module_name << std::endl;
return 1;