aboutsummaryrefslogtreecommitdiff
path: root/src/script/common/c_internal.cpp
blob: b19af9f82145bf7f5287705250f1382c7c39bf3e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "common/c_internal.h"
#include "debug.h"
#include "log.h"
#include "porting.h"
#include "settings.h"

std::string script_get_backtrace(lua_State *L)
{
	lua_rawgeti(L, LUA_REGISTRYINDEX, CUSTOM_RIDX_BACKTRACE);
	lua_call(L, 0, 1);
	std::string result = luaL_checkstring(L, -1);
	lua_pop(L, 1);
	return result;
}

int script_exception_wrapper(lua_State *L, lua_CFunction f)
{
	try {
		return f(L);  // Call wrapped function and return result.
	} catch (const char *s) {  // Catch and convert exceptions.
		lua_pushstring(L, s);
	} catch (std::exception &e) {
		lua_pushstring(L, e.what());
	}
	return lua_error(L);  // Rethrow as a Lua error.
}

/*
 * Note that we can't get tracebacks for LUA_ERRMEM or LUA_ERRERR (without
 * hacking Lua internals).  For LUA_ERRMEM, this is because memory errors will
 * not execute the error handler, and by the time lua_pcall returns the
 * execution stack will have already been unwound.  For LUA_ERRERR, there was
 * another error while trying to generate a backtrace from a LUA_ERRRUN.  It is
 * presumed there is an error with the internal Lua state and thus not possible
 * to gather a coherent backtrace.  Realistically, the best we can do here is
 * print which C function performed the failing pcall.
 */
void script_error(lua_State *L, int pcall_result, const char *mod, const char *fxn)
{
	if (pcall_result == 0)
		return;

	const char *err_type;
	switch (pcall_result) {
	case LUA_ERRRUN:
		err_type = "Runtime";
		break;
	case LUA_ERRMEM:
		err_type = "OOM";
		break;
	case LUA_ERRERR:
		err_type = "Double fault";
		break;
	default:
		err_type = "Unknown";
	}

	if (!mod)
		mod = "??";

	if (!fxn)
		fxn = "??";

	const char *err_descr = lua_tostring(L, -1);
	if (!err_descr)
		err_descr = "<no description>";

	char buf[256];
	porting::mt_snprintf(buf, sizeof(buf), "%s error from mod '%s' in callback %s(): ",
		err_type, mod, fxn);

	std::string err_msg(buf);
	err_msg += err_descr;

	if (pcall_result == LUA_ERRMEM) {
		err_msg += "\nCurrent Lua memory usage: "
			+ itos(lua_gc(L, LUA_GCCOUNT, 0) >> 10) + " MB";
	}

	throw LuaError(err_msg);
}

// Push the list of callbacks (a lua table).
// Then push nargs arguments.
// Then call this function, which
// - runs the callbacks
// - replaces the table and arguments with the return value,
//     computed depending on mode
void script_run_callbacks_f(lua_State *L, int nargs,
	RunCallbacksMode mode, const char *fxn)
{
	FATAL_ERROR_IF(lua_gettop(L) < nargs + 1, "Not enough arguments");

	// Insert error handler
	PUSH_ERROR_HANDLER(L);
	int error_handler = lua_gettop(L) - nargs - 1;
	lua_insert(L, error_handler);

	// Insert run_callbacks between error handler and table
	lua_getglobal(L, "core");
	lua_getfield(L, -1, "run_callbacks");
	lua_remove(L, -2);
	lua_insert(L, error_handler + 1);

	// Insert mode after table
	lua_pushnumber(L, (int) mode);
	lua_insert(L, error_handler + 3);

	// Stack now looks like this:
	// ... <error handler> <run_callbacks> <table> <mode> <arg#1> <arg#2> ... <arg#n>

	int result = lua_pcall(L, nargs + 2, 1, error_handler);
	if (result != 0)
		script_error(L, result, NULL, fxn);

	lua_remove(L, error_handler);
}

static void script_log(lua_State *L, const std::string &message,
	std::ostream &log_to, bool do_error, int stack_depth)
{
	lua_Debug ar;

	log_to << message << " ";
	if (lua_getstack(L, stack_depth, &ar)) {
		FATAL_ERROR_IF(!lua_getinfo(L, "Sl", &ar), "lua_getinfo() failed");
		log_to << "(at " << ar.short_src << ":" << ar.currentline << ")";
	} else {
		log_to << "(at ?:?)";
	}
	log_to << std::endl;

	if (do_error)
		script_error(L, LUA_ERRRUN, NULL, NULL);
	else
		infostream << script_get_backtrace(L) << std::endl;
}

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

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

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