/* Modular support
  *
  * (C) 2003-2022 Anope Team
  * Contact us at team@anope.org
  *
  * Please read COPYING and README for further details.
  */
 
 #include "services.h"
 #include "modules.h"
 #include "users.h"
 #include "regchannel.h"
 #include "config.h"
 
 #include <sys/types.h>
 #include <sys/stat.h>
 #ifndef _WIN32
 #include <dirent.h>
 #include <sys/types.h>
 #include <dlfcn.h>
 #endif
 
 std::list<Module *> ModuleManager::Modules;
 std::vector<Module *> ModuleManager::EventHandlers[I_SIZE];
 
 #ifdef _WIN32
 void ModuleManager::CleanupRuntimeDirectory()
 {
 	Anope::string dirbuf = Anope::DataDir + "/runtime";
 
 	Log(LOG_DEBUG) << "Cleaning out Module run time directory (" << dirbuf << ") - this may take a moment, please wait";
 
 	DIR *dirp = opendir(dirbuf.c_str());
 	if (!dirp)
 	{
 		Log(LOG_DEBUG) << "Cannot open directory (" << dirbuf << ")";
 		return;
 	}
 
 	for (dirent *dp; (dp = readdir(dirp));)
 	{
 		if (!dp->d_ino)
 			continue;
 		if (Anope::string(dp->d_name).equals_cs(".") || Anope::string(dp->d_name).equals_cs(".."))
 			continue;
 		Anope::string filebuf = dirbuf + "/" + dp->d_name;
 		unlink(filebuf.c_str());
 	}
 
 	closedir(dirp);
 }
 
 /**
  * Copy the module from the modules folder to the runtime folder.
  * This will prevent module updates while the modules is loaded from
  * triggering a segfault, as the actual file in use will be in the
  * runtime folder.
  * @param name the name of the module to copy
  * @param output the destination to copy the module to
  * @return MOD_ERR_OK on success
  */
 static ModuleReturn moduleCopyFile(const Anope::string &name, Anope::string &output)
 {
 	Anope::string input = Anope::ModuleDir + "/modules/" + name + ".so";
 
 	struct stat s;
 	if (stat(input.c_str(), &s) == -1)
 		return MOD_ERR_NOEXIST;
 	else if (!S_ISREG(s.st_mode))
 		return MOD_ERR_NOEXIST;
 
 	std::ifstream source(input.c_str(), std::ios_base::in | std::ios_base::binary);
 	if (!source.is_open())
 		return MOD_ERR_NOEXIST;
 
 	char *tmp_output = strdup(output.c_str());
 	int target_fd = mkstemp(tmp_output);
 	if (target_fd == -1 || close(target_fd) == -1)
 	{
 		free(tmp_output);
 		source.close();
 		return MOD_ERR_FILE_IO;
 	}
 	output = tmp_output;
 	free(tmp_output);
 
 	Log(LOG_DEBUG_2) << "Runtime module location: " << output;
 
 	std::ofstream target(output.c_str(), std::ios_base::in | std::ios_base::binary);
 	if (!target.is_open())
 	{
 		source.close();
 		return MOD_ERR_FILE_IO;
 	}
 
 	int want = s.st_size;
 	char buffer[1024];
 	while (want > 0 && !source.fail() && !target.fail())
 	{
 		source.read(buffer, std::min(want, static_cast<int>(sizeof(buffer))));
 		int read_len = source.gcount();
 
 		target.write(buffer, read_len);
 		want -= read_len;
 	}
 
 	source.close();
 	target.close();
 
 	return !source.fail() && !target.fail() ? MOD_ERR_OK : MOD_ERR_FILE_IO;
 }
 #endif
 
 /* This code was found online at https://web.archive.org/web/20180318184211/https://www.linuxjournal.com/article/3687#comment-26593
  *
  * This function will take a pointer from either dlsym or GetProcAddress and cast it in
  * a way that won't cause C++ warnings/errors to come up.
  */
 template <class TYPE> static TYPE function_cast(void *symbol)
 {
 	union
 	{
 		void *symbol;
 		TYPE function;
 	} cast;
 	cast.symbol = symbol;
 	return cast.function;
 }
 
 ModuleReturn ModuleManager::LoadModule(const Anope::string &modname, User *u)
 {
 	if (modname.empty())
 		return MOD_ERR_PARAMS;
 
 	if (FindModule(modname))
 		return MOD_ERR_EXISTS;
 
 	Log(LOG_DEBUG) << "Trying to load module: " << modname;
 
 #ifdef _WIN32
 	/* Generate the filename for the temporary copy of the module */
 	Anope::string pbuf = Anope::DataDir + "/runtime/" + modname + ".so.XXXXXX";
 
 	/* Don't skip return value checking! -GD */
 	ModuleReturn ret = moduleCopyFile(modname, pbuf);
 	if (ret != MOD_ERR_OK)
 	{
 		if (ret == MOD_ERR_NOEXIST)
 			Log(LOG_TERMINAL) << "Error while loading " << modname << " (file does not exist)";
 		else if (ret == MOD_ERR_FILE_IO)
 			Log(LOG_TERMINAL) << "Error while loading " << modname << " (file IO error, check file permissions and diskspace)";
 		return ret;
 	}
 #else
 	Anope::string pbuf = Anope::ModuleDir + "/modules/" + modname + ".so";
 #endif
 
 	dlerror();
 	void *handle = dlopen(pbuf.c_str(), RTLD_NOW);
 	const char *err = dlerror();
 	if (!handle)
 	{
 		if (err && *err)
 			Log() << err;
 		return MOD_ERR_NOLOAD;
 	}
 
 	try
 	{
 		ModuleVersion v = GetVersion(handle);
 
 		if (v.GetMajor() < Anope::VersionMajor() || (v.GetMajor() == Anope::VersionMajor() && v.GetMinor() < Anope::VersionMinor()))
 		{
 			Log() << "Module " << modname << " is compiled against an older version of Anope " << v.GetMajor() << "." << v.GetMinor() << ", this is " << Anope::VersionShort();
 			dlclose(handle);
 			return MOD_ERR_VERSION;
 		}
 		else if (v.GetMajor() > Anope::VersionMajor() || (v.GetMajor() == Anope::VersionMajor() && v.GetMinor() > Anope::VersionMinor()))
 		{
 			Log() << "Module " << modname << " is compiled against a newer version of Anope " << v.GetMajor() << "." << v.GetMinor() << ", this is " << Anope::VersionShort();
 			dlclose(handle);
 			return MOD_ERR_VERSION;
 		}
 		else if (v.GetPatch() < Anope::VersionPatch())
 		{
 			Log() << "Module " << modname << " is compiled against an older version of Anope, " << v.GetMajor() << "." << v.GetMinor() << "." << v.GetPatch() << ", this is " << Anope::VersionShort();
 			dlclose(handle);
 			return MOD_ERR_VERSION;
 		}
 		else if (v.GetPatch() > Anope::VersionPatch())
 		{
 			Log() << "Module " << modname << " is compiled against a newer version of Anope, " << v.GetMajor() << "." << v.GetMinor() << "." << v.GetPatch() << ", this is " << Anope::VersionShort();
 			dlclose(handle);
 			return MOD_ERR_VERSION;
 		}
 		else
 		{
 			Log(LOG_DEBUG_2) << "Module " << modname << " is compiled against current version of Anope " << Anope::VersionShort();
 		}
 	}
 	catch (const ModuleException &ex)
 	{
 		/* this error has already been logged */
 		dlclose(handle);
 		return MOD_ERR_NOLOAD;
 	}
 
 	dlerror();
 	Module *(*func)(const Anope::string &, const Anope::string &) = function_cast<Module *(*)(const Anope::string &, const Anope::string &)>(dlsym(handle, "AnopeInit"));
 	err = dlerror();
 	if (!func)
 	{
 		Log() << "No init function found, not an Anope module";
 		if (err && *err)
 			Log(LOG_DEBUG) << err;
 		dlclose(handle);
 		return MOD_ERR_NOLOAD;
 	}
 
 	/* Create module. */
 	Anope::string nick;
 	if (u)
 		nick = u->nick;
 
 	Module *m;
 
 	ModuleReturn moderr = MOD_ERR_OK;
 	try
 	{
 		m = func(modname, nick);
 	}
 	catch (const ModuleException &ex)
 	{
 		Log() << "Error while loading " << modname << ": " << ex.GetReason();
 		moderr = MOD_ERR_EXCEPTION;
 	}
 
 	if (moderr != MOD_ERR_OK)
 	{
 		if (dlclose(handle))
 			Log() << dlerror();
 		return moderr;
 	}
 
 	m->filename = pbuf;
 	m->handle = handle;
 
 	/* Initialize config */
 	try
 	{
 		m->OnReload(Config);
 	}
 	catch (const ModuleException &ex)
 	{
 		Log() << "Module " << modname << " couldn't load:" << ex.GetReason();
 		moderr = MOD_ERR_EXCEPTION;
 	}
 	catch (const ConfigException &ex)
 	{
 		Log() << "Module " << modname << " couldn't load due to configuration problems: " << ex.GetReason();
 		moderr = MOD_ERR_EXCEPTION;
 	}
 	catch (const NotImplementedException &ex)
 	{
 	}
 
 	if (moderr != MOD_ERR_OK)
 	{
 		DeleteModule(m);
 		return moderr;
 	}
 
 	Log(LOG_DEBUG) << "Module " << modname << " loaded.";
 
 	/* Attach module to all events */
 	for (unsigned i = 0; i < I_SIZE; ++i)
 		EventHandlers[i].push_back(m);
 
 	m->Prioritize();
 
 	FOREACH_MOD(OnModuleLoad, (u, m));
 
 	return MOD_ERR_OK;
 }
 
 ModuleVersion ModuleManager::GetVersion(void *handle)
 {
 	dlerror();
 	ModuleVersionC (*func)() = function_cast<ModuleVersionC (*)()>(dlsym(handle, "AnopeVersion"));;
 	if (!func)
 	{
 		Log() << "No version function found, not an Anope module";
 
 		const char *err = dlerror();
 		if (err && *err)
 			Log(LOG_DEBUG) << err;
 
 		throw ModuleException("No version");
 	}
 
 	return func();
 }
 
 ModuleReturn ModuleManager::UnloadModule(Module *m, User *u)
 {
 	if (!m)
 		return MOD_ERR_PARAMS;
 
 	FOREACH_MOD(OnModuleUnload, (u, m));
 
 	return DeleteModule(m);
 }
 
 Module *ModuleManager::FindModule(const Anope::string &name)
 {
 	for (std::list<Module *>::const_iterator it = Modules.begin(), it_end = Modules.end(); it != it_end; ++it)
 	{
 		Module *m = *it;
 
 		if (m->name.equals_ci(name))
 			return m;
 	}
 
 	return NULL;
 }
 
 Module *ModuleManager::FindFirstOf(ModType type)
 {
 	for (std::list<Module *>::const_iterator it = Modules.begin(), it_end = Modules.end(); it != it_end; ++it)
 	{
 		Module *m = *it;
 
 		if (m->type & type)
 			return m;
 	}
 
 	return NULL;
 }
 
 void ModuleManager::RequireVersion(int major, int minor, int patch)
 {
 	if (Anope::VersionMajor() > major)
 		return;
 	else if (Anope::VersionMajor() == major)
 	{
 		if (minor == -1)
 			return;
 		else if (Anope::VersionMinor() > minor)
 			return;
 		else if (Anope::VersionMinor() == minor)
 		{
 			if (patch == -1)
 				return;
 			else if (Anope::VersionPatch() > patch)
 				return;
 			else if (Anope::VersionPatch() == patch)
 				return;
 		}
 	}
 
 	throw ModuleException("This module requires version " + stringify(major) + "." + stringify(minor) + "." + stringify(patch) + " - this is " + Anope::VersionShort());
 }
 
 ModuleReturn ModuleManager::DeleteModule(Module *m)
 {
 	if (!m || !m->handle)
 		return MOD_ERR_PARAMS;
 
 	void *handle = m->handle;
 	Anope::string filename = m->filename;
 
 	Log(LOG_DEBUG) << "Unloading module " << m->name;
 
 	dlerror();
 	void (*destroy_func)(Module *m) = function_cast<void (*)(Module *)>(dlsym(m->handle, "AnopeFini"));
 	const char *err = dlerror();
 	if (!destroy_func || (err && *err))
 	{
 		Log() << "No destroy function found for " << m->name << ", chancing delete...";
 		delete m; /* we just have to chance they haven't overwrote the delete operator then... */
 	}
 	else
 		destroy_func(m); /* Let the module delete it self, just in case */
 
 	if (dlclose(handle))
 		Log() << dlerror();
 
 #ifdef _WIN32
 	if (!filename.empty())
 		unlink(filename.c_str());
 #endif
 
 	return MOD_ERR_OK;
 }
 
 void ModuleManager::DetachAll(Module *mod)
 {
 	for (unsigned i = 0; i < I_SIZE; ++i)
 	{
 		std::vector<Module *> &mods = EventHandlers[i];
 		std::vector<Module *>::iterator it2 = std::find(mods.begin(), mods.end(), mod);
 		if (it2 != mods.end())
 			mods.erase(it2);
 	}
 }
 
 bool ModuleManager::SetPriority(Module *mod, Priority s)
 {
 	for (unsigned i = 0; i < I_SIZE; ++i)
 		SetPriority(mod, static_cast<Implementation>(i), s);
 
 	return true;
 }
 
 bool ModuleManager::SetPriority(Module *mod, Implementation i, Priority s, Module **modules, size_t sz)
 {
 	/** To change the priority of a module, we first find its position in the vector,
 	 * then we find the position of the other modules in the vector that this module
 	 * wants to be before/after. We pick off either the first or last of these depending
 	 * on which they want, and we make sure our module is *at least* before or after
 	 * the first or last of this subset, depending again on the type of priority.
 	 */
 
 	/* Locate our module. This is O(n) but it only occurs on module load so we're
 	 * not too bothered about it
 	 */
 	size_t source = 0;
 	bool found = false;
 	for (size_t x = 0, end = EventHandlers[i].size(); x != end; ++x)
 		if (EventHandlers[i][x] == mod)
 		{
 			source = x;
 			found = true;
 			break;
 		}
 
 	/* Eh? this module doesn't exist, probably trying to set priority on an event
 	 * they're not attached to.
 	 */
 	if (!found)
 		return false;
 
 	size_t swap_pos = 0;
 	bool swap = true;
 	switch (s)
 	{
 		/* Dummy value */
 		case PRIORITY_DONTCARE:
 			swap = false;
 			break;
 		/* Module wants to be first, sod everything else */
 		case PRIORITY_FIRST:
 			swap_pos = 0;
 			break;
 		/* Module is submissive and wants to be last... awww. */
 		case PRIORITY_LAST:
 			if (EventHandlers[i].empty())
 				swap_pos = 0;
 			else
 				swap_pos = EventHandlers[i].size() - 1;
 			break;
 		/* Place this module after a set of other modules */
 		case PRIORITY_AFTER:
 			/* Find the latest possible position */
 			swap_pos = 0;
 			swap = false;
 			for (size_t x = 0, end = EventHandlers[i].size(); x != end; ++x)
 				for (size_t n = 0; n < sz; ++n)
 					if (modules[n] && EventHandlers[i][x] == modules[n] && x >= swap_pos && source <= swap_pos)
 					{
 						swap_pos = x;
 						swap = true;
 					}
 			break;
 		/* Place this module before a set of other modules */
 		case PRIORITY_BEFORE:
 			swap_pos = EventHandlers[i].size() - 1;
 			swap = false;
 			for (size_t x = 0, end = EventHandlers[i].size(); x != end; ++x)
 				for (size_t n = 0; n < sz; ++n)
 					if (modules[n] && EventHandlers[i][x] == modules[n] && x <= swap_pos && source >= swap_pos)
 					{
 						swap = true;
 						swap_pos = x;
 					}
 	}
 
 	/* Do we need to swap? */
 	if (swap && swap_pos != source)
 	{
 		/* Suggestion from Phoenix, "shuffle" the modules to better retain call order */
 		int increment = 1;
 
 		if (source > swap_pos)
 			increment = -1;
 
 		for (unsigned j = source; j != swap_pos; j += increment)
 		{
 			if (j + increment > EventHandlers[i].size() - 1 || (!j && increment == -1))
 				continue;
 
 			std::swap(EventHandlers[i][j], EventHandlers[i][j + increment]);
 		}
 	}
 
 	return true;
 }
 
 void ModuleManager::UnloadAll()
 {
 	std::vector<Anope::string> modules;
 	for (size_t i = 1, j = 0; i != MT_END; j |= i, i <<= 1)
 		for (std::list<Module *>::iterator it = Modules.begin(), it_end = Modules.end(); it != it_end; ++it)
 		{
 			Module *m = *it;
 			if ((m->type & j) == m->type)
 				modules.push_back(m->name);
 		}
 
 	for (unsigned i = 0; i < modules.size(); ++i)
 	{
 		Module *m = FindModule(modules[i]);
 		if (m != NULL)
 			UnloadModule(m, NULL);
 	}
 }

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