1/*
2** $Id: ldblib.c $
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.
26*/
27static const char *const HOOKKEY = "_HOOKKEY";
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*/
35static void checkstack (lua_State *L, lua_State *L1, int n) {
36  if (l_unlikely(L != L1 && !lua_checkstack(L1, n)))
37    luaL_error(L, "stack overflow");
38}
39
40
41static int db_getregistry (lua_State *L) {
42  lua_pushvalue(L, LUA_REGISTRYINDEX);
43  return 1;
44}
45
46
47static 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
56static int db_setmetatable (lua_State *L) {
57  int t = lua_type(L, 2);
58  luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table");
59  lua_settop(L, 2);
60  lua_setmetatable(L, 1);
61  return 1;  /* return 1st argument */
62}
63
64
65static int db_getuservalue (lua_State *L) {
66  int n = (int)luaL_optinteger(L, 2, 1);
67  if (lua_type(L, 1) != LUA_TUSERDATA)
68    luaL_pushfail(L);
69  else if (lua_getiuservalue(L, 1, n) != LUA_TNONE) {
70    lua_pushboolean(L, 1);
71    return 2;
72  }
73  return 1;
74}
75
76
77static int db_setuservalue (lua_State *L) {
78  int n = (int)luaL_optinteger(L, 3, 1);
79  luaL_checktype(L, 1, LUA_TUSERDATA);
80  luaL_checkany(L, 2);
81  lua_settop(L, 2);
82  if (!lua_setiuservalue(L, 1, n))
83    luaL_pushfail(L);
84  return 1;
85}
86
87
88/*
89** Auxiliary function used by several library functions: check for
90** an optional thread as function's first argument and set 'arg' with
91** 1 if this argument is present (so that functions can skip it to
92** access their other arguments)
93*/
94static lua_State *getthread (lua_State *L, int *arg) {
95  if (lua_isthread(L, 1)) {
96    *arg = 1;
97    return lua_tothread(L, 1);
98  }
99  else {
100    *arg = 0;
101    return L;  /* function will operate over current thread */
102  }
103}
104
105
106/*
107** Variations of 'lua_settable', used by 'db_getinfo' to put results
108** from 'lua_getinfo' into result table. Key is always a string;
109** value can be a string, an int, or a boolean.
110*/
111static void settabss (lua_State *L, const char *k, const char *v) {
112  lua_pushstring(L, v);
113  lua_setfield(L, -2, k);
114}
115
116static void settabsi (lua_State *L, const char *k, int v) {
117  lua_pushinteger(L, v);
118  lua_setfield(L, -2, k);
119}
120
121static void settabsb (lua_State *L, const char *k, int v) {
122  lua_pushboolean(L, v);
123  lua_setfield(L, -2, k);
124}
125
126
127/*
128** In function 'db_getinfo', the call to 'lua_getinfo' may push
129** results on the stack; later it creates the result table to put
130** these objects. Function 'treatstackoption' puts the result from
131** 'lua_getinfo' on top of the result table so that it can call
132** 'lua_setfield'.
133*/
134static void treatstackoption (lua_State *L, lua_State *L1, const char *fname) {
135  if (L == L1)
136    lua_rotate(L, -2, 1);  /* exchange object and table */
137  else
138    lua_xmove(L1, L, 1);  /* move object to the "main" stack */
139  lua_setfield(L, -2, fname);  /* put object into table */
140}
141
142
143/*
144** Calls 'lua_getinfo' and collects all results in a new table.
145** L1 needs stack space for an optional input (function) plus
146** two optional outputs (function and line table) from function
147** 'lua_getinfo'.
148*/
149static int db_getinfo (lua_State *L) {
150  lua_Debug ar;
151  int arg;
152  lua_State *L1 = getthread(L, &arg);
153  const char *options = luaL_optstring(L, arg+2, "flnSrtu");
154  checkstack(L, L1, 3);
155  luaL_argcheck(L, options[0] != '>', arg + 2, "invalid option '>'");
156  if (lua_isfunction(L, arg + 1)) {  /* info about a function? */
157    options = lua_pushfstring(L, ">%s", options);  /* add '>' to 'options' */
158    lua_pushvalue(L, arg + 1);  /* move function to 'L1' stack */
159    lua_xmove(L, L1, 1);
160  }
161  else {  /* stack level */
162    if (!lua_getstack(L1, (int)luaL_checkinteger(L, arg + 1), &ar)) {
163      luaL_pushfail(L);  /* level out of range */
164      return 1;
165    }
166  }
167  if (!lua_getinfo(L1, options, &ar))
168    return luaL_argerror(L, arg+2, "invalid option");
169  lua_newtable(L);  /* table to collect results */
170  if (strchr(options, 'S')) {
171    lua_pushlstring(L, ar.source, ar.srclen);
172    lua_setfield(L, -2, "source");
173    settabss(L, "short_src", ar.short_src);
174    settabsi(L, "linedefined", ar.linedefined);
175    settabsi(L, "lastlinedefined", ar.lastlinedefined);
176    settabss(L, "what", ar.what);
177  }
178  if (strchr(options, 'l'))
179    settabsi(L, "currentline", ar.currentline);
180  if (strchr(options, 'u')) {
181    settabsi(L, "nups", ar.nups);
182    settabsi(L, "nparams", ar.nparams);
183    settabsb(L, "isvararg", ar.isvararg);
184  }
185  if (strchr(options, 'n')) {
186    settabss(L, "name", ar.name);
187    settabss(L, "namewhat", ar.namewhat);
188  }
189  if (strchr(options, 'r')) {
190    settabsi(L, "ftransfer", ar.ftransfer);
191    settabsi(L, "ntransfer", ar.ntransfer);
192  }
193  if (strchr(options, 't'))
194    settabsb(L, "istailcall", ar.istailcall);
195  if (strchr(options, 'L'))
196    treatstackoption(L, L1, "activelines");
197  if (strchr(options, 'f'))
198    treatstackoption(L, L1, "func");
199  return 1;  /* return table */
200}
201
202
203static int db_getlocal (lua_State *L) {
204  int arg;
205  lua_State *L1 = getthread(L, &arg);
206  int nvar = (int)luaL_checkinteger(L, arg + 2);  /* local-variable index */
207  if (lua_isfunction(L, arg + 1)) {  /* function argument? */
208    lua_pushvalue(L, arg + 1);  /* push function */
209    lua_pushstring(L, lua_getlocal(L, NULL, nvar));  /* push local name */
210    return 1;  /* return only name (there is no value) */
211  }
212  else {  /* stack-level argument */
213    lua_Debug ar;
214    const char *name;
215    int level = (int)luaL_checkinteger(L, arg + 1);
216    if (l_unlikely(!lua_getstack(L1, level, &ar)))  /* out of range? */
217      return luaL_argerror(L, arg+1, "level out of range");
218    checkstack(L, L1, 1);
219    name = lua_getlocal(L1, &ar, nvar);
220    if (name) {
221      lua_xmove(L1, L, 1);  /* move local value */
222      lua_pushstring(L, name);  /* push name */
223      lua_rotate(L, -2, 1);  /* re-order */
224      return 2;
225    }
226    else {
227      luaL_pushfail(L);  /* no name (nor value) */
228      return 1;
229    }
230  }
231}
232
233
234static int db_setlocal (lua_State *L) {
235  int arg;
236  const char *name;
237  lua_State *L1 = getthread(L, &arg);
238  lua_Debug ar;
239  int level = (int)luaL_checkinteger(L, arg + 1);
240  int nvar = (int)luaL_checkinteger(L, arg + 2);
241  if (l_unlikely(!lua_getstack(L1, level, &ar)))  /* out of range? */
242    return luaL_argerror(L, arg+1, "level out of range");
243  luaL_checkany(L, arg+3);
244  lua_settop(L, arg+3);
245  checkstack(L, L1, 1);
246  lua_xmove(L, L1, 1);
247  name = lua_setlocal(L1, &ar, nvar);
248  if (name == NULL)
249    lua_pop(L1, 1);  /* pop value (if not popped by 'lua_setlocal') */
250  lua_pushstring(L, name);
251  return 1;
252}
253
254
255/*
256** get (if 'get' is true) or set an upvalue from a closure
257*/
258static int auxupvalue (lua_State *L, int get) {
259  const char *name;
260  int n = (int)luaL_checkinteger(L, 2);  /* upvalue index */
261  luaL_checktype(L, 1, LUA_TFUNCTION);  /* closure */
262  name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
263  if (name == NULL) return 0;
264  lua_pushstring(L, name);
265  lua_insert(L, -(get+1));  /* no-op if get is false */
266  return get + 1;
267}
268
269
270static int db_getupvalue (lua_State *L) {
271  return auxupvalue(L, 1);
272}
273
274
275static int db_setupvalue (lua_State *L) {
276  luaL_checkany(L, 3);
277  return auxupvalue(L, 0);
278}
279
280
281/*
282** Check whether a given upvalue from a given closure exists and
283** returns its index
284*/
285static void *checkupval (lua_State *L, int argf, int argnup, int *pnup) {
286  void *id;
287  int nup = (int)luaL_checkinteger(L, argnup);  /* upvalue index */
288  luaL_checktype(L, argf, LUA_TFUNCTION);  /* closure */
289  id = lua_upvalueid(L, argf, nup);
290  if (pnup) {
291    luaL_argcheck(L, id != NULL, argnup, "invalid upvalue index");
292    *pnup = nup;
293  }
294  return id;
295}
296
297
298static int db_upvalueid (lua_State *L) {
299  void *id = checkupval(L, 1, 2, NULL);
300  if (id != NULL)
301    lua_pushlightuserdata(L, id);
302  else
303    luaL_pushfail(L);
304  return 1;
305}
306
307
308static int db_upvaluejoin (lua_State *L) {
309  int n1, n2;
310  checkupval(L, 1, 2, &n1);
311  checkupval(L, 3, 4, &n2);
312  luaL_argcheck(L, !lua_iscfunction(L, 1), 1, "Lua function expected");
313  luaL_argcheck(L, !lua_iscfunction(L, 3), 3, "Lua function expected");
314  lua_upvaluejoin(L, 1, n1, 3, n2);
315  return 0;
316}
317
318
319/*
320** Call hook function registered at hook table for the current
321** thread (if there is one)
322*/
323static void hookf (lua_State *L, lua_Debug *ar) {
324  static const char *const hooknames[] =
325    {"call", "return", "line", "count", "tail call"};
326  lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
327  lua_pushthread(L);
328  if (lua_rawget(L, -2) == LUA_TFUNCTION) {  /* is there a hook function? */
329    lua_pushstring(L, hooknames[(int)ar->event]);  /* push event name */
330    if (ar->currentline >= 0)
331      lua_pushinteger(L, ar->currentline);  /* push current line */
332    else lua_pushnil(L);
333    lua_assert(lua_getinfo(L, "lS", ar));
334    lua_call(L, 2, 0);  /* call hook function */
335  }
336}
337
338
339/*
340** Convert a string mask (for 'sethook') into a bit mask
341*/
342static int makemask (const char *smask, int count) {
343  int mask = 0;
344  if (strchr(smask, 'c')) mask |= LUA_MASKCALL;
345  if (strchr(smask, 'r')) mask |= LUA_MASKRET;
346  if (strchr(smask, 'l')) mask |= LUA_MASKLINE;
347  if (count > 0) mask |= LUA_MASKCOUNT;
348  return mask;
349}
350
351
352/*
353** Convert a bit mask (for 'gethook') into a string mask
354*/
355static char *unmakemask (int mask, char *smask) {
356  int i = 0;
357  if (mask & LUA_MASKCALL) smask[i++] = 'c';
358  if (mask & LUA_MASKRET) smask[i++] = 'r';
359  if (mask & LUA_MASKLINE) smask[i++] = 'l';
360  smask[i] = '\0';
361  return smask;
362}
363
364
365static int db_sethook (lua_State *L) {
366  int arg, mask, count;
367  lua_Hook func;
368  lua_State *L1 = getthread(L, &arg);
369  if (lua_isnoneornil(L, arg+1)) {  /* no hook? */
370    lua_settop(L, arg+1);
371    func = NULL; mask = 0; count = 0;  /* turn off hooks */
372  }
373  else {
374    const char *smask = luaL_checkstring(L, arg+2);
375    luaL_checktype(L, arg+1, LUA_TFUNCTION);
376    count = (int)luaL_optinteger(L, arg + 3, 0);
377    func = hookf; mask = makemask(smask, count);
378  }
379  if (!luaL_getsubtable(L, LUA_REGISTRYINDEX, HOOKKEY)) {
380    /* table just created; initialize it */
381    lua_pushliteral(L, "k");
382    lua_setfield(L, -2, "__mode");  /** hooktable.__mode = "k" */
383    lua_pushvalue(L, -1);
384    lua_setmetatable(L, -2);  /* metatable(hooktable) = hooktable */
385  }
386  checkstack(L, L1, 1);
387  lua_pushthread(L1); lua_xmove(L1, L, 1);  /* key (thread) */
388  lua_pushvalue(L, arg + 1);  /* value (hook function) */
389  lua_rawset(L, -3);  /* hooktable[L1] = new Lua hook */
390  lua_sethook(L1, func, mask, count);
391  return 0;
392}
393
394
395static int db_gethook (lua_State *L) {
396  int arg;
397  lua_State *L1 = getthread(L, &arg);
398  char buff[5];
399  int mask = lua_gethookmask(L1);
400  lua_Hook hook = lua_gethook(L1);
401  if (hook == NULL) {  /* no hook? */
402    luaL_pushfail(L);
403    return 1;
404  }
405  else if (hook != hookf)  /* external hook? */
406    lua_pushliteral(L, "external hook");
407  else {  /* hook table must exist */
408    lua_getfield(L, LUA_REGISTRYINDEX, HOOKKEY);
409    checkstack(L, L1, 1);
410    lua_pushthread(L1); lua_xmove(L1, L, 1);
411    lua_rawget(L, -2);   /* 1st result = hooktable[L1] */
412    lua_remove(L, -2);  /* remove hook table */
413  }
414  lua_pushstring(L, unmakemask(mask, buff));  /* 2nd result = mask */
415  lua_pushinteger(L, lua_gethookcount(L1));  /* 3rd result = count */
416  return 3;
417}
418
419
420static int db_debug (lua_State *L) {
421  for (;;) {
422    char buffer[250];
423    lua_writestringerror("%s", "lua_debug> ");
424    if (fgets(buffer, sizeof(buffer), stdin) == NULL ||
425        strcmp(buffer, "cont\n") == 0)
426      return 0;
427    if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
428        lua_pcall(L, 0, 0, 0))
429      lua_writestringerror("%s\n", luaL_tolstring(L, -1, NULL));
430    lua_settop(L, 0);  /* remove eventual returns */
431  }
432}
433
434
435static int db_traceback (lua_State *L) {
436  int arg;
437  lua_State *L1 = getthread(L, &arg);
438  const char *msg = lua_tostring(L, arg + 1);
439  if (msg == NULL && !lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */
440    lua_pushvalue(L, arg + 1);  /* return it untouched */
441  else {
442    int level = (int)luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);
443    luaL_traceback(L, L1, msg, level);
444  }
445  return 1;
446}
447
448
449static int db_setcstacklimit (lua_State *L) {
450  int limit = (int)luaL_checkinteger(L, 1);
451  int res = lua_setcstacklimit(L, limit);
452  lua_pushinteger(L, res);
453  return 1;
454}
455
456
457static const luaL_Reg dblib[] = {
458  {"debug", db_debug},
459  {"getuservalue", db_getuservalue},
460  {"gethook", db_gethook},
461  {"getinfo", db_getinfo},
462  {"getlocal", db_getlocal},
463  {"getregistry", db_getregistry},
464  {"getmetatable", db_getmetatable},
465  {"getupvalue", db_getupvalue},
466  {"upvaluejoin", db_upvaluejoin},
467  {"upvalueid", db_upvalueid},
468  {"setuservalue", db_setuservalue},
469  {"sethook", db_sethook},
470  {"setlocal", db_setlocal},
471  {"setmetatable", db_setmetatable},
472  {"setupvalue", db_setupvalue},
473  {"traceback", db_traceback},
474  {"setcstacklimit", db_setcstacklimit},
475  {NULL, NULL}
476};
477
478
479LUAMOD_API int luaopen_debug (lua_State *L) {
480  luaL_newlib(L, dblib);
481  return 1;
482}
483
484