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1 /*
2 ** $Id: ldblib.c,v 1.151.1.1 2017/04/19 17:20:42 roberto Exp $
3 ** Interface from Lua to its debug API
4 ** See Copyright Notice in lua.h
5 */
6 
7 #define ldblib_c
8 #define LUA_LIB
9 
10 #include "lprefix.h"
11 
12 
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 
17 #include "lua.h"
18 
19 #include "lauxlib.h"
20 #include "lualib.h"
21 
22 
23 /*
24 ** The hook table at registry[&HOOKKEY] maps threads to their current
25 ** hook function. (We only need the unique address of 'HOOKKEY'.)
26 */
27 static const int HOOKKEY = 0;
28 
29 
30 /*
31 ** If L1 != L, L1 can be in any state, and therefore there are no
32 ** guarantees about its stack space; any push in L1 must be
33 ** checked.
34 */
checkstack(lua_State * L,lua_State * L1,int n)35 static void checkstack (lua_State *L, lua_State *L1, int n) {
36   if (L != L1 && !lua_checkstack(L1, n))
37     luaL_error(L, "stack overflow");
38 }
39 
40 
db_getregistry(lua_State * L)41 static int db_getregistry (lua_State *L) {
42   lua_pushvalue(L, LUA_REGISTRYINDEX);
43   return 1;
44 }
45 
46 
db_getmetatable(lua_State * L)47 static int db_getmetatable (lua_State *L) {
48   luaL_checkany(L, 1);
49   if (!lua_getmetatable(L, 1)) {
50     lua_pushnil(L);  /* no metatable */
51   }
52   return 1;
53 }
54 
55 
db_setmetatable(lua_State * L)56 static int db_setmetatable (lua_State *L) {
57   int t = lua_type(L, 2);
58   luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
59                     "nil or table expected");
60   lua_settop(L, 2);
61   lua_setmetatable(L, 1);
62   return 1;  /* return 1st argument */
63 }
64 
65 
db_getuservalue(lua_State * L)66 static int db_getuservalue (lua_State *L) {
67   if (lua_type(L, 1) != LUA_TUSERDATA)
68     lua_pushnil(L);
69   else
70     lua_getuservalue(L, 1);
71   return 1;
72 }
73 
74 
db_setuservalue(lua_State * L)75 static int db_setuservalue (lua_State *L) {
76   luaL_checktype(L, 1, LUA_TUSERDATA);
77   luaL_checkany(L, 2);
78   lua_settop(L, 2);
79   lua_setuservalue(L, 1);
80   return 1;
81 }
82 
83 
84 /*
85 ** Auxiliary function used by several library functions: check for
86 ** an optional thread as function's first argument and set 'arg' with
87 ** 1 if this argument is present (so that functions can skip it to
88 ** access their other arguments)
89 */
getthread(lua_State * L,int * arg)90 static lua_State *getthread (lua_State *L, int *arg) {
91   if (lua_isthread(L, 1)) {
92     *arg = 1;
93     return lua_tothread(L, 1);
94   }
95   else {
96     *arg = 0;
97     return L;  /* function will operate over current thread */
98   }
99 }
100 
101 
102 /*
103 ** Variations of 'lua_settable', used by 'db_getinfo' to put results
104 ** from 'lua_getinfo' into result table. Key is always a string;
105 ** value can be a string, an int, or a boolean.
106 */
settabss(lua_State * L,const char * k,const char * v)107 static void settabss (lua_State *L, const char *k, const char *v) {
108   lua_pushstring(L, v);
109   lua_setfield(L, -2, k);
110 }
111 
settabsi(lua_State * L,const char * k,int v)112 static void settabsi (lua_State *L, const char *k, int v) {
113   lua_pushinteger(L, v);
114   lua_setfield(L, -2, k);
115 }
116 
settabsb(lua_State * L,const char * k,int v)117 static void settabsb (lua_State *L, const char *k, int v) {
118   lua_pushboolean(L, v);
119   lua_setfield(L, -2, k);
120 }
121 
122 
123 /*
124 ** In function 'db_getinfo', the call to 'lua_getinfo' may push
125 ** results on the stack; later it creates the result table to put
126 ** these objects. Function 'treatstackoption' puts the result from
127 ** 'lua_getinfo' on top of the result table so that it can call
128 ** 'lua_setfield'.
129 */
treatstackoption(lua_State * L,lua_State * L1,const char * fname)130 static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {
131   if (L == L1)
132     lua_rotate(L, -2, 1);  /* exchange object and table */
133   else
134     lua_xmove(L1, L, 1);  /* move object to the "main" stack */
135   lua_setfield(L, -2, fname);  /* put object into table */
136 }
137 
138 
139 /*
140 ** Calls 'lua_getinfo' and collects all results in a new table.
141 ** L1 needs stack space for an optional input (function) plus
142 ** two optional outputs (function and line table) from function
143 ** 'lua_getinfo'.
144 */
db_getinfo(lua_State * L)145 static int db_getinfo (lua_State *L) {
146   lua_Debug ar;
147   int arg;
148   lua_State *L1 = getthread(L, &arg);
149   const char *options = luaL_optstring(L, arg+2, "flnStu");
150   checkstack(L, L1, 3);
151   if (lua_isfunction(L, arg + 1)) {  /* info about a function? */
152     options = lua_pushfstring(L, ">%s", options);  /* add '>' to 'options' */
153     lua_pushvalue(L, arg + 1);  /* move function to 'L1' stack */
154     lua_xmove(L, L1, 1);
155   }
156   else {  /* stack level */
157     if (!lua_getstack(L1, (int)luaL_checkinteger(L, arg + 1), &ar)) {
158       lua_pushnil(L);  /* level out of range */
159       return 1;
160     }
161   }
162   if (!lua_getinfo(L1, options, &ar))
163     return luaL_argerror(L, arg+2, "invalid option");
164   lua_newtable(L);  /* table to collect results */
165   if (strchr(options, 'S')) {
166     settabss(L, "source", ar.source);
167     settabss(L, "short_src", ar.short_src);
168     settabsi(L, "linedefined", ar.linedefined);
169     settabsi(L, "lastlinedefined", ar.lastlinedefined);
170     settabss(L, "what", ar.what);
171   }
172   if (strchr(options, 'l'))
173     settabsi(L, "currentline", ar.currentline);
174   if (strchr(options, 'u')) {
175     settabsi(L, "nups", ar.nups);
176     settabsi(L, "nparams", ar.nparams);
177     settabsb(L, "isvararg", ar.isvararg);
178   }
179   if (strchr(options, 'n')) {
180     settabss(L, "name", ar.name);
181     settabss(L, "namewhat", ar.namewhat);
182   }
183   if (strchr(options, 't'))
184     settabsb(L, "istailcall", ar.istailcall);
185   if (strchr(options, 'L'))
186     treatstackoption(L, L1, "activelines");
187   if (strchr(options, 'f'))
188     treatstackoption(L, L1, "func");
189   return 1;  /* return table */
190 }
191 
192 
db_getlocal(lua_State * L)193 static int db_getlocal (lua_State *L) {
194   int arg;
195   lua_State *L1 = getthread(L, &arg);
196   lua_Debug ar;
197   const char *name;
198   int nvar = (int)luaL_checkinteger(L, arg + 2);  /* local-variable index */
199   if (lua_isfunction(L, arg + 1)) {  /* function argument? */
200     lua_pushvalue(L, arg + 1);  /* push function */
201     lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */
202     return 1;  /* return only name (there is no value) */
203   }
204   else {  /* stack-level argument */
205     int level = (int)luaL_checkinteger(L, arg + 1);
206     if (!lua_getstack(L1, level, &ar))  /* out of range? */
207       return luaL_argerror(L, arg+1, "level out of range");
208     checkstack(L, L1, 1);
209     name = lua_getlocal(L1, &ar, nvar);
210     if (name) {
211       lua_xmove(L1, L, 1);  /* move local value */
212       lua_pushstring(L, name);  /* push name */
213       lua_rotate(L, -2, 1);  /* re-order */
214       return 2;
215     }
216     else {
217       lua_pushnil(L);  /* no name (nor value) */
218       return 1;
219     }
220   }
221 }
222 
223 
db_setlocal(lua_State * L)224 static int db_setlocal (lua_State *L) {
225   int arg;
226   const char *name;
227   lua_State *L1 = getthread(L, &arg);
228   lua_Debug ar;
229   int level = (int)luaL_checkinteger(L, arg + 1);
230   int nvar = (int)luaL_checkinteger(L, arg + 2);
231   if (!lua_getstack(L1, level, &ar))  /* out of range? */
232     return luaL_argerror(L, arg+1, "level out of range");
233   luaL_checkany(L, arg+3);
234   lua_settop(L, arg+3);
235   checkstack(L, L1, 1);
236   lua_xmove(L, L1, 1);
237   name = lua_setlocal(L1, &ar, nvar);
238   if (name == NULL)
239     lua_pop(L1, 1);  /* pop value (if not popped by 'lua_setlocal') */
240   lua_pushstring(L, name);
241   return 1;
242 }
243 
244 
245 /*
246 ** get (if 'get' is true) or set an upvalue from a closure
247 */
auxupvalue(lua_State * L,int get)248 static int auxupvalue (lua_State *L, int get) {
249   const char *name;
250   int n = (int)luaL_checkinteger(L, 2);  /* upvalue index */
251   luaL_checktype(L, 1, LUA_TFUNCTION);  /* closure */
252   name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
253   if (name == NULL) return 0;
254   lua_pushstring(L, name);
255   lua_insert(L, -(get+1));  /* no-op if get is false */
256   return get + 1;
257 }
258 
259 
db_getupvalue(lua_State * L)260 static int db_getupvalue (lua_State *L) {
261   return auxupvalue(L, 1);
262 }
263 
264 
db_setupvalue(lua_State * L)265 static int db_setupvalue (lua_State *L) {
266   luaL_checkany(L, 3);
267   return auxupvalue(L, 0);
268 }
269 
270 
271 /*
272 ** Check whether a given upvalue from a given closure exists and
273 ** returns its index
274 */
checkupval(lua_State * L,int argf,int argnup)275 static int checkupval (lua_State *L, int argf, int argnup) {
276   int nup = (int)luaL_checkinteger(L, argnup);  /* upvalue index */
277   luaL_checktype(L, argf, LUA_TFUNCTION);  /* closure */
278   luaL_argcheck(L, (lua_getupvalue(L, argf, nup) != NULL), argnup,
279                    "invalid upvalue index");
280   return nup;
281 }
282 
283 
db_upvalueid(lua_State * L)284 static int db_upvalueid (lua_State *L) {
285   int n = checkupval(L, 1, 2);
286   lua_pushlightuserdata(L, lua_upvalueid(L, 1, n));
287   return 1;
288 }
289 
290 
db_upvaluejoin(lua_State * L)291 static int db_upvaluejoin (lua_State *L) {
292   int n1 = checkupval(L, 1, 2);
293   int n2 = checkupval(L, 3, 4);
294   luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
295   luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
296   lua_upvaluejoin(L, 1, n1, 3, n2);
297   return 0;
298 }
299 
300 
301 /*
302 ** Call hook function registered at hook table for the current
303 ** thread (if there is one)
304 */
hookf(lua_State * L,lua_Debug * ar)305 static void hookf (lua_State *L, lua_Debug *ar) {
306   static const char *const hooknames[] =
307     {"call", "return", "line", "count", "tail call"};
308   lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
309   lua_pushthread(L);
310   if (lua_rawget(L, -2) == LUA_TFUNCTION) {  /* is there a hook function? */
311     lua_pushstring(L, hooknames[(int)ar->event]);  /* push event name */
312     if (ar->currentline >= 0)
313       lua_pushinteger(L, ar->currentline);  /* push current line */
314     else lua_pushnil(L);
315     lua_assert(lua_getinfo(L, "lS", ar));
316     lua_call(L, 2, 0);  /* call hook function */
317   }
318 }
319 
320 
321 /*
322 ** Convert a string mask (for 'sethook') into a bit mask
323 */
makemask(const char * smask,int count)324 static int makemask (const char *smask, int count) {
325   int mask = 0;
326   if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
327   if (strchr(smask, 'r')) mask |= LUA_MASKRET;
328   if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
329   if (count > 0) mask |= LUA_MASKCOUNT;
330   return mask;
331 }
332 
333 
334 /*
335 ** Convert a bit mask (for 'gethook') into a string mask
336 */
unmakemask(int mask,char * smask)337 static char *unmakemask (int mask, char *smask) {
338   int i = 0;
339   if (mask & LUA_MASKCALL) smask[i++] = 'c';
340   if (mask & LUA_MASKRET) smask[i++] = 'r';
341   if (mask & LUA_MASKLINE) smask[i++] = 'l';
342   smask[i] = '\0';
343   return smask;
344 }
345 
346 
db_sethook(lua_State * L)347 static int db_sethook (lua_State *L) {
348   int arg, mask, count;
349   lua_Hook func;
350   lua_State *L1 = getthread(L, &arg);
351   if (lua_isnoneornil(L, arg+1)) {  /* no hook? */
352     lua_settop(L, arg+1);
353     func = NULL; mask = 0; count = 0;  /* turn off hooks */
354   }
355   else {
356     const char *smask = luaL_checkstring(L, arg+2);
357     luaL_checktype(L, arg+1, LUA_TFUNCTION);
358     count = (int)luaL_optinteger(L, arg + 3, 0);
359     func = hookf; mask = makemask(smask, count);
360   }
361   if (lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY) == LUA_TNIL) {
362     lua_createtable(L, 0, 2);  /* create a hook table */
363     lua_pushvalue(L, -1);
364     lua_rawsetp(L, LUA_REGISTRYINDEX, &HOOKKEY);  /* set it in position */
365     lua_pushstring(L, "k");
366     lua_setfield(L, -2, "__mode");  /** hooktable.__mode = "k" */
367     lua_pushvalue(L, -1);
368     lua_setmetatable(L, -2);  /* setmetatable(hooktable) = hooktable */
369   }
370   checkstack(L, L1, 1);
371   lua_pushthread(L1); lua_xmove(L1, L, 1);  /* key (thread) */
372   lua_pushvalue(L, arg + 1);  /* value (hook function) */
373   lua_rawset(L, -3);  /* hooktable[L1] = new Lua hook */
374   lua_sethook(L1, func, mask, count);
375   return 0;
376 }
377 
378 
db_gethook(lua_State * L)379 static int db_gethook (lua_State *L) {
380   int arg;
381   lua_State *L1 = getthread(L, &arg);
382   char buff[5];
383   int mask = lua_gethookmask(L1);
384   lua_Hook hook = lua_gethook(L1);
385   if (hook == NULL)  /* no hook? */
386     lua_pushnil(L);
387   else if (hook != hookf)  /* external hook? */
388     lua_pushliteral(L, "external hook");
389   else {  /* hook table must exist */
390     lua_rawgetp(L, LUA_REGISTRYINDEX, &HOOKKEY);
391     checkstack(L, L1, 1);
392     lua_pushthread(L1); lua_xmove(L1, L, 1);
393     lua_rawget(L, -2);   /* 1st result = hooktable[L1] */
394     lua_remove(L, -2);  /* remove hook table */
395   }
396   lua_pushstring(L, unmakemask(mask, buff));  /* 2nd result = mask */
397   lua_pushinteger(L, lua_gethookcount(L1));  /* 3rd result = count */
398   return 3;
399 }
400 
401 
db_debug(lua_State * L)402 static int db_debug (lua_State *L) {
403   for (;;) {
404     char buffer[250];
405     lua_writestringerror("%s", "lua_debug> ");
406     if (fgets(buffer, sizeof(buffer), stdin) == 0 ||
407         strcmp(buffer, "cont\n") == 0)
408       return 0;
409     if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
410         lua_pcall(L, 0, 0, 0))
411       lua_writestringerror("%s\n", lua_tostring(L, -1));
412     lua_settop(L, 0);  /* remove eventual returns */
413   }
414 }
415 
416 
db_traceback(lua_State * L)417 static int db_traceback (lua_State *L) {
418   int arg;
419   lua_State *L1 = getthread(L, &arg);
420   const char *msg = lua_tostring(L, arg + 1);
421   if (msg == NULL && !lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */
422     lua_pushvalue(L, arg + 1);  /* return it untouched */
423   else {
424     int level = (int)luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);
425     luaL_traceback(L, L1, msg, level);
426   }
427   return 1;
428 }
429 
430 
431 static const luaL_Reg dblib[] = {
432   {"debug", db_debug},
433   {"getuservalue", db_getuservalue},
434   {"gethook", db_gethook},
435   {"getinfo", db_getinfo},
436   {"getlocal", db_getlocal},
437   {"getregistry", db_getregistry},
438   {"getmetatable", db_getmetatable},
439   {"getupvalue", db_getupvalue},
440   {"upvaluejoin", db_upvaluejoin},
441   {"upvalueid", db_upvalueid},
442   {"setuservalue", db_setuservalue},
443   {"sethook", db_sethook},
444   {"setlocal", db_setlocal},
445   {"setmetatable", db_setmetatable},
446   {"setupvalue", db_setupvalue},
447   {"traceback", db_traceback},
448   {NULL, NULL}
449 };
450 
451 
luaopen_debug(lua_State * L)452 LUAMOD_API int luaopen_debug (lua_State *L) {
453   luaL_newlib(L, dblib);
454   return 1;
455 }
456 
457