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Fix segfault in deprecation logging due to tail call, log by default (#…

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rubenwardy committed Oct 31, 2020
1 parent 2dff3dd commit 89dd05fdf35ce465fcc2b3588337f79f818a78aa
@@ -1220,10 +1220,10 @@ movement_gravity (Gravity) float 9.81
[**Advanced]

# Handling for deprecated Lua API calls:
# - legacy: (try to) mimic old behaviour (default for release).
# - log: mimic and log backtrace of deprecated call (default for debug).
# - none: Do not log deprecated calls
# - log: mimic and log backtrace of deprecated call (default).
# - error: abort on usage of deprecated call (suggested for mod developers).
deprecated_lua_api_handling (Deprecated Lua API handling) enum legacy legacy,log,error
deprecated_lua_api_handling (Deprecated Lua API handling) enum log none,log,error

# Number of extra blocks that can be loaded by /clearobjects at once.
# This is a trade-off between sqlite transaction overhead and
@@ -358,11 +358,7 @@ void set_default_settings(Settings *settings)
settings->setDefault("disallow_empty_password", "false");
settings->setDefault("disable_anticheat", "false");
settings->setDefault("enable_rollback_recording", "false");
#ifdef NDEBUG
settings->setDefault("deprecated_lua_api_handling", "legacy");
#else
settings->setDefault("deprecated_lua_api_handling", "log");
#endif

settings->setDefault("kick_msg_shutdown", "Server shutting down.");
settings->setDefault("kick_msg_crash", "This server has experienced an internal error. You will now be disconnected.");
@@ -155,24 +155,28 @@ static void script_log(lua_State *L, const std::string &message,
infostream << script_get_backtrace(L) << std::endl;
}

void log_deprecated(lua_State *L, const std::string &message, int stack_depth)
DeprecatedHandlingMode get_deprecated_handling_mode()
{
static thread_local bool configured = false;
static thread_local bool do_log = false;
static thread_local bool do_error = false;
static thread_local DeprecatedHandlingMode ret = DeprecatedHandlingMode::Ignore;

// Only read settings on first call
if (!configured) {
std::string value = g_settings->get("deprecated_lua_api_handling");
if (value == "log") {
do_log = true;
ret = DeprecatedHandlingMode::Log;
} else if (value == "error") {
do_log = true;
do_error = true;
ret = DeprecatedHandlingMode::Error;
}
configured = true;
}

if (do_log)
script_log(L, message, warningstream, do_error, stack_depth);
return ret;
}

void log_deprecated(lua_State *L, const std::string &message, int stack_depth)
{
DeprecatedHandlingMode mode = get_deprecated_handling_mode();
if (mode != DeprecatedHandlingMode::Ignore)
script_log(L, message, warningstream, mode == DeprecatedHandlingMode::Error, stack_depth);
}
@@ -114,5 +114,25 @@ void script_error(lua_State *L, int pcall_result, const char *mod, const char *f
void script_run_callbacks_f(lua_State *L, int nargs,
RunCallbacksMode mode, const char *fxn);

enum class DeprecatedHandlingMode {
Ignore,
Log,
Error
};

/**
* Reads `deprecated_lua_api_handling` in settings, returns cached value.
*
* @return DeprecatedHandlingMode
*/
DeprecatedHandlingMode get_deprecated_handling_mode();

/**
* Handles a deprecation warning based on user settings
*
* @param L Lua State
* @param message The deprecation method
* @param stack_depth How far on the stack to the first user function (ie: not builtin or core)
*/
void log_deprecated(lua_State *L, const std::string &message,
int stack_depth=1);
@@ -100,32 +100,21 @@ bool ModApiBase::registerFunction(lua_State *L, const char *name,
return true;
}

std::unordered_map<std::string, luaL_Reg> ModApiBase::m_deprecated_wrappers;
bool ModApiBase::m_error_deprecated_calls = false;

int ModApiBase::l_deprecated_function(lua_State *L)
int ModApiBase::l_deprecated_function(lua_State *L, const char *good, const char *bad, lua_CFunction func)
{
thread_local std::vector<u64> deprecated_logged;

DeprecatedHandlingMode dep_mode = get_deprecated_handling_mode();
if (dep_mode == DeprecatedHandlingMode::Ignore)
return func(L);

u64 start_time = porting::getTimeUs();
lua_Debug ar;

// Get function name for lookup
FATAL_ERROR_IF(!lua_getstack(L, 0, &ar), "lua_getstack() failed");
FATAL_ERROR_IF(!lua_getinfo(L, "n", &ar), "lua_getinfo() failed");

// Combine name with line and script backtrace
// Get caller name with line and script backtrace
FATAL_ERROR_IF(!lua_getstack(L, 1, &ar), "lua_getstack() failed");
FATAL_ERROR_IF(!lua_getinfo(L, "Sl", &ar), "lua_getinfo() failed");

// Get parent class to get the wrappers map
luaL_checktype(L, 1, LUA_TUSERDATA);
void *ud = lua_touserdata(L, 1);
ModApiBase *o = *(ModApiBase**)ud;

// New function and new function name
auto it = o->m_deprecated_wrappers.find(ar.name);

// Get backtrace and hash it to reduce the warning flood
std::string backtrace = ar.short_src;
backtrace.append(":").append(std::to_string(ar.currentline));
@@ -135,46 +124,16 @@ int ModApiBase::l_deprecated_function(lua_State *L)
== deprecated_logged.end()) {

deprecated_logged.emplace_back(hash);
warningstream << "Call to deprecated function '" << ar.name << "', please use '"
<< it->second.name << "' at " << backtrace << std::endl;
warningstream << "Call to deprecated function '" << bad << "', please use '"
<< good << "' at " << backtrace << std::endl;

if (m_error_deprecated_calls)
if (dep_mode == DeprecatedHandlingMode::Error)
script_error(L, LUA_ERRRUN, NULL, NULL);
}

u64 end_time = porting::getTimeUs();
g_profiler->avg("l_deprecated_function", end_time - start_time);

return it->second.func(L);
return func(L);
}

void ModApiBase::markAliasDeprecated(luaL_Reg *reg)
{
std::string value = g_settings->get("deprecated_lua_api_handling");
m_error_deprecated_calls = value == "error";

if (!m_error_deprecated_calls && value != "log")
return;

const char *last_name = nullptr;
lua_CFunction last_func = nullptr;

// ! Null termination !
while (reg->func) {
if (last_func == reg->func) {
// Duplicate found
luaL_Reg original_reg;
// Do not inline struct. Breaks MSVC or is error-prone
original_reg.name = last_name;
original_reg.func = reg->func;
m_deprecated_wrappers.emplace(
std::pair<std::string, luaL_Reg>(reg->name, original_reg));
reg->func = l_deprecated_function;
} else {
last_func = reg->func;
last_name = reg->name;
}

++reg;
}
}
@@ -41,7 +41,6 @@ class Environment;
class ServerInventoryManager;

class ModApiBase : protected LuaHelper {

public:
static ScriptApiBase* getScriptApiBase(lua_State *L);
static Server* getServer(lua_State *L);
@@ -75,10 +74,18 @@ class ModApiBase : protected LuaHelper {
lua_CFunction func,
int top);

static int l_deprecated_function(lua_State *L);
static void markAliasDeprecated(luaL_Reg *reg);
private:
// <old_name> = { <new_name>, <new_function> }
static std::unordered_map<std::string, luaL_Reg> m_deprecated_wrappers;
static bool m_error_deprecated_calls;
/**
* A wrapper for deprecated functions.
*
* When called, handles the deprecation according to user settings and then calls `func`.
*
* @throws Lua Error if required by the user settings.
*
* @param L Lua state
* @param good Name of good function/method
* @param bad Name of deprecated function/method
* @param func Actual implementation of function
* @return value from `func`
*/
static int l_deprecated_function(lua_State *L, const char *good, const char *bad, lua_CFunction func);
};
@@ -29,7 +29,16 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include "common/c_internal.h"

#define luamethod(class, name) {#name, class::l_##name}
#define luamethod_aliased(class, name, alias) {#name, class::l_##name}, {#alias, class::l_##name}

#define luamethod_dep(class, good, bad) \
{#bad, [](lua_State *L) -> int { \
return l_deprecated_function(L, #bad, #good, &class::l_##good); \
}}

#define luamethod_aliased(class, name, alias) \
luamethod(class, name), \
luamethod_dep(class, name, alias)

#define API_FCT(name) registerFunction(L, #name, l_##name, top)

// For future use
@@ -122,7 +122,6 @@ void LuaPerlinNoise::Register(lua_State *L)

lua_pop(L, 1);

markAliasDeprecated(methods);
luaL_openlib(L, 0, methods, 0);
lua_pop(L, 1);

@@ -381,7 +380,6 @@ void LuaPerlinNoiseMap::Register(lua_State *L)

lua_pop(L, 1);

markAliasDeprecated(methods);
luaL_openlib(L, 0, methods, 0);
lua_pop(L, 1);

@@ -2278,7 +2278,6 @@ void ObjectRef::Register(lua_State *L)

lua_pop(L, 1); // drop metatable

markAliasDeprecated(methods);
luaL_openlib(L, 0, methods, 0); // fill methodtable
lua_pop(L, 1); // drop methodtable
}
@@ -2316,10 +2315,9 @@ luaL_Reg ObjectRef::methods[] = {
luamethod(ObjectRef, get_nametag_attributes),

luamethod_aliased(ObjectRef, set_velocity, setvelocity),
luamethod(ObjectRef, add_velocity),
{"add_player_velocity", ObjectRef::l_add_velocity},
luamethod_aliased(ObjectRef, add_velocity, add_player_velocity),
luamethod_aliased(ObjectRef, get_velocity, getvelocity),
{"get_player_velocity", ObjectRef::l_get_velocity},
luamethod_dep(ObjectRef, get_velocity, get_player_velocity),

// LuaEntitySAO-only
luamethod_aliased(ObjectRef, set_acceleration, setacceleration),

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