Fix crash and reworked find_memloc

Author: s1lentq

metamod/src/mlist.cpp

@@ -86,9 +86,9 @@ MPlugin* MPluginList::find(const char* findpath)
 // Find a plugin that uses the given memory location.
 MPlugin* MPluginList::find_memloc(void* memptr)
 {
-	for (auto p : m_plugins) {
-		if (p->m_sys_module.load(memptr))
-			return p;
+	module_handle_t ptr = CSysModule::find(memptr);
+	if (ptr != CSysModule::INVALID_HANDLE) {
+		return find(ptr);
 	}
 
 	return nullptr;

metamod/src/mreg.cpp

@@ -1,6 +1,6 @@
 #include "precompiled.h"
 
-MRegCmd::MRegCmd(const char* cmd_name, REG_CMD_FN cmd_handler, MPlugin* cmd_plugin) : m_pfunction(cmd_handler), m_plugid(cmd_plugin->index()), m_status(RG_VALID)
+MRegCmd::MRegCmd(const char* cmd_name, REG_CMD_FN cmd_handler, MPlugin* cmd_plugin) : m_pfunction(cmd_handler), m_plugid(cmd_plugin ? cmd_plugin->index() : 0), m_status(RG_VALID)
 {
 	m_name = Q_strdup(cmd_name);
 }

metamod/src/reg_support.cpp

@@ -31,8 +31,7 @@ void EXT_FUNC meta_AddServerCommand(const char* cmd_name, void (*function)())
 	META_DEBUG(4, "called: meta_AddServerCommand; cmd_name=%s, function=%d, plugin=%s", cmd_name, function, plug ? plug->file() : "unknown");
 
 	if (!plug) {
-		META_ERROR("Failed to find memloc for regcmd '%s'", cmd_name);
-		return;
+		META_WARNING("Failed to find memloc for regcmd '%s'", cmd_name);
 	}
 
 	// See if this command was previously registered, ie a "reloaded" plugin.
@@ -64,13 +63,11 @@ void EXT_FUNC meta_CVarRegister(cvar_t* pCvar)
 
 	// try to find which plugin is registering this cvar
 	if (!plug) {
-		META_ERROR("Failed to find memloc for regcvar '%s'", pCvar->name);
-		return;
+		META_WARNING("Failed to find memloc for regcvar '%s'", pCvar->name);
 	}
 
 	// See if this cvar was previously registered, ie a "reloaded" plugin.
 	auto reg = g_regCvars->find(pCvar->name);
-
 	if (!reg) {
 		reg = g_regCvars->add(pCvar, plug);
 		CVAR_REGISTER(reg->getcvar());
@@ -89,7 +86,6 @@ void EXT_FUNC meta_CVarRegister(cvar_t* pCvar)
 // commands) nor any useful actions to perform upon plugin unload (like the
 // commands and cvars).  This merely provides differently located storage
 // for the string.
-
 int EXT_FUNC meta_RegUserMsg(const char* pszName, int iSize)
 {
 	char* cp = Q_strdup(pszName);

metamod/src/sys_module.cpp

@@ -31,7 +31,14 @@ char *CSysModule::find_pattern(char *pos, int range, const char *pattern, size_t
 module_handle_t CSysModule::load(void *addr)
 {
 	MEMORY_BASIC_INFORMATION mem;
-	VirtualQuery(addr, &mem, sizeof(mem));
+	if (!VirtualQuery(addr, &mem, sizeof(mem)))
+		return INVALID_HANDLE;
+
+	if (mem.State != MEM_COMMIT)
+		return INVALID_HANDLE;
+
+	if (!mem.AllocationBase)
+		return INVALID_HANDLE;
 
 	IMAGE_DOS_HEADER *dos = (IMAGE_DOS_HEADER *)mem.AllocationBase;
 	IMAGE_NT_HEADERS *pe = (IMAGE_NT_HEADERS *)((uintptr_t)dos + (uintptr_t)dos->e_lfanew);
@@ -47,6 +54,16 @@ module_handle_t CSysModule::load(void *addr)
 	return m_handle;
 }
 
+module_handle_t CSysModule::find(void *addr)
+{
+	module_handle_t hHandle = INVALID_HANDLE;
+	if (!GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT | GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS, reinterpret_cast<LPCTSTR>(addr), &hHandle)) {
+		return INVALID_HANDLE;
+	}
+
+	return hHandle;
+}
+
 module_handle_t CSysModule::load(const char *filepath)
 {
 	if (!m_handle) {
@@ -121,6 +138,21 @@ module_handle_t CSysModule::load(void *addr)
 	return m_handle;
 }
 
+module_handle_t CSysModule::find(void *addr)
+{
+	Dl_info dlinfo;
+	if ((!dladdr(addr, &dlinfo) && !dlinfo.dli_fbase) || !dlinfo.dli_fname) {
+		return false;
+	}
+
+	module_handle_t hHandle = INVALID_HANDLE;
+	if (!(hHandle = dlopen(dlinfo.dli_fname, RTLD_NOW | RTLD_NOLOAD))) {
+		return INVALID_HANDLE;
+	}
+
+	return hHandle;
+}
+
 module_handle_t CSysModule::load(const char *filepath)
 {
 	if (!m_handle) {

metamod/src/sys_module.h

@@ -24,6 +24,7 @@ class CSysModule
 	char *find_string_push(const char *string);
 	char *find_pattern(char *pos, int range, const char *pattern, size_t len);
 
+	static module_handle_t find(void *addr);
 	static const char *getloaderror();
 	static const module_handle_t INVALID_HANDLE;