summaryrefslogtreecommitdiffstats
path: root/nse_main.cc
blob: 2382688bd72815b7837c0e947451059182eca525 (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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
#include "nmap.h"
#include "nbase.h"
#include "nmap_error.h"
#include "portlist.h"
#include "nsock.h"
#include "NmapOps.h"
#include "timing.h"
#include "Target.h"
#include "nmap_tty.h"
#include "xml.h"

#include "nse_main.h"
#include "nse_utility.h"
#include "nse_db.h"
#include "nse_fs.h"
#include "nse_nsock.h"
#include "nse_nmaplib.h"
#include "nse_openssl.h"
#include "nse_debug.h"
#include "nse_lpeg.h"
#include "nse_libssh2.h"
#include "nse_zlib.h"

#include <math.h>

#define NSE_MAIN "NSE_MAIN" /* the main function */

/* Script Scan phases */
#define NSE_PRE_SCAN  "NSE_PRE_SCAN"
#define NSE_SCAN      "NSE_SCAN"
#define NSE_POST_SCAN "NSE_POST_SCAN"

/* These are indices into the registry, for data shared with nse_main.lua. The
   definitions here must match those in nse_main.lua. */
#define NSE_YIELD "NSE_YIELD"
#define NSE_BASE "NSE_BASE"
#define NSE_WAITING_TO_RUNNING "NSE_WAITING_TO_RUNNING"
#define NSE_DESTRUCTOR "NSE_DESTRUCTOR"
#define NSE_SELECTED_BY_NAME "NSE_SELECTED_BY_NAME"
#define NSE_CURRENT_HOSTS "NSE_CURRENT_HOSTS"

#define NSE_FORMAT_TABLE "NSE_FORMAT_TABLE"
#define NSE_FORMAT_XML "NSE_FORMAT_XML"
#define NSE_PARALLELISM "NSE_PARALLELISM"

#ifndef MAXPATHLEN
#  define MAXPATHLEN 2048
#endif

extern NmapOps o;

/* global object to store Pre-Scan and Post-Scan script results */
static ScriptResults script_scan_results;

static int timedOut (lua_State *L)
{
  Target *target = nseU_gettarget(L, 1);
  lua_pushboolean(L, target->timedOut(NULL));
  return 1;
}

static int startTimeOutClock (lua_State *L)
{
  Target *target = nseU_gettarget(L, 1);
  if (!target->timeOutClockRunning())
    target->startTimeOutClock(NULL);
  return 0;
}

static int stopTimeOutClock (lua_State *L)
{
  Target *target = nseU_gettarget(L, 1);
  if (target->timeOutClockRunning())
    target->stopTimeOutClock(NULL);
  return 0;
}

static int next_port (lua_State *L)
{
  lua_settop(L, 2);
  lua_pushvalue(L, lua_upvalueindex(1));
  lua_pushvalue(L, 2);
  if (lua_next(L, -2) == 0)
    return 0;
  else {
    lua_pop(L, 1); /* pop boolean value */
    return 1;
  }
}

static int ports (lua_State *L)
{
  static const int states[] = {
    PORT_OPEN,
    PORT_OPENFILTERED,
    PORT_UNFILTERED,
    PORT_HIGHEST_STATE /* last one marks end */
  };
  Target *target = nseU_gettarget(L, 1);
  PortList *plist = &(target->ports);
  Port *current = NULL;
  Port port;
  lua_newtable(L);
  for (int i = 0; states[i] != PORT_HIGHEST_STATE; i++)
    while ((current = plist->nextPort(current, &port, TCPANDUDPANDSCTP,
            states[i])) != NULL)
    {
      lua_createtable(L, 0, NSE_NUM_PORTINFO_FIELDS);
      set_portinfo(L, target, current);
      lua_pushboolean(L, 1);
      lua_rawset(L, -3);
    }
  lua_pushcclosure(L, next_port, 1);
  lua_pushnil(L);
  lua_pushnil(L);
  return 3;
}

static int script_set_output (lua_State *L)
{
  ScriptResult *sr = new ScriptResult;
  sr->set_output_tab(L, 1);
  script_scan_results.insert(sr);
  return 0;
}

static int host_set_output (lua_State *L)
{
  ScriptResult *sr = new ScriptResult;
  Target *target = nseU_gettarget(L, 1);
  sr->set_output_tab(L, 2);
  target->scriptResults.insert(sr);
  return 0;
}

static int port_set_output (lua_State *L)
{
  Port *p;
  Port port;
  ScriptResult *sr = new ScriptResult;
  Target *target = nseU_gettarget(L, 1);
  p = nseU_getport(L, target, &port, 2);
  sr->set_output_tab(L, 3);
  target->ports.addScriptResult(p->portno, p->proto, sr);
  target->ports.numscriptresults++;
  return 0;
}

static int key_was_pressed (lua_State *L)
{
  lua_pushboolean(L, keyWasPressed());
  return 1;
}

static int scp (lua_State *L)
{
  static const char * const ops[] = {"printStats", "printStatsIfNecessary",
    "mayBePrinted", "endTask", NULL};
  ScanProgressMeter *progress =
    (ScanProgressMeter *) lua_touserdata(L, lua_upvalueindex(1));
  switch (luaL_checkoption(L, 1, NULL, ops))
  {
    case 0: /* printStats */
      progress->printStats((double) luaL_checknumber(L, 2), NULL);
      break;
    case 1:
      progress->printStatsIfNecessary((double) luaL_checknumber(L, 2), NULL);
      break;
    case 2: /*mayBePrinted */
      lua_pushboolean(L, progress->mayBePrinted(NULL));
      return 1;
    case 3: /* endTask */
      progress->endTask(NULL, NULL);
      delete progress;
      break;
  }
  return 0;
}

static int scan_progress_meter (lua_State *L)
{
  lua_pushlightuserdata(L, new ScanProgressMeter(luaL_checkstring(L, 1)));
  lua_pushcclosure(L, scp, 1);
  return 1;
}

/* This is like nmap.log_write, but doesn't append "NSE:" to the beginning of
   messages. It is only used internally by nse_main.lua and is not available to
   scripts. */
static int l_log_write(lua_State *L)
{
  static const char *const ops[] = {"stdout", "stderr", NULL};
  static const int logs[] = {LOG_STDOUT, LOG_STDERR};
  int log = logs[luaL_checkoption(L, 1, NULL, ops)];
  log_write(log, "%s", luaL_checkstring(L, 2));
  return 0;
}

static int l_xml_start_tag(lua_State *L)
{
  const char *name;

  name = luaL_checkstring(L, 1);
  xml_open_start_tag(name);

  if (lua_isnoneornil(L, 2)) {
    lua_newtable(L);
    lua_replace(L, 2);
  }

  for (lua_pushnil(L); lua_next(L, 2); lua_pop(L, 1))
    xml_attribute(luaL_checkstring(L, -2), "%s", luaL_checkstring(L, -1));

  xml_close_start_tag();

  return 0;
}

static int l_xml_end_tag(lua_State *L)
{
  xml_end_tag();

  return 0;
}

static int l_xml_write_escaped(lua_State *L)
{
  const char *text;

  text = luaL_checkstring(L, 1);
  xml_write_escaped("%s", text);

  return 0;
}

static int l_xml_newline(lua_State *L)
{
  xml_newline();

  return 0;
}

static int l_protect_xml(lua_State *L)
{
  const char *text;
  size_t len;
  std::string output;

  text = luaL_checklstring(L, 1, &len);
  output = protect_xml(std::string(text, len));
  lua_pushlstring(L, output.c_str(), output.size());

  return 1;
}

static int nse_fetch (lua_State *L, int (*fetch)(char *, size_t, const char *))
{
  char path[MAXPATHLEN];
  const char *input = luaL_checkstring(L, 1);
  switch (fetch(path, sizeof(path), input))
  {
    case 0: // no such path
      lua_pushnil(L);
      lua_pushfstring(L, "no path to file/directory: %s", lua_tostring(L, 1));
      break;
    case 1: // file returned
      lua_pushliteral(L, "file");
      lua_pushstring(L, path);
      break;
    case 2: // directory returned
      if (input[strlen(input) - 1] == '/') {
        lua_pushliteral(L, "directory");
      }
      else {
        lua_pushliteral(L, "bare_directory");
      }
      lua_pushstring(L, path);
      break;
    default:
      return luaL_error(L, "nse_fetch returned bad code");
  }
  return 2;
}

static bool filename_is_absolute(const char *file) {
  if (file[0] == '/')
    return true;
#ifdef WIN32
  if ((file[0] != '\0' && file[1] == ':') || file[0] == '\\')
    return true;
#endif
  return false;
}

/* This is a modification of nmap_fetchfile that first looks for an
 * absolute file name.
 */
static int nse_fetchfile_absolute(char *path, size_t path_len, const char *file) {
  if (filename_is_absolute(file)) {
    if (o.debugging > 1)
      log_write(LOG_STDOUT, "%s: Trying absolute path %s\n", SCRIPT_ENGINE, file);
    Strncpy(path, file, path_len);
    return file_is_readable(file);
  }

  return nmap_fetchfile(path, path_len, file);
}

/* This is a modification of nmap_fetchfile specialized to look for files
 * in the scripts subdirectory. If the path is absolute, it is always tried
 * verbatim. Otherwise, the file is looked for under scripts/, and then finally
 * in the current directory.
 */
static int nse_fetchscript(char *path, size_t path_len, const char *file) {
  std::string scripts_path = std::string(SCRIPT_ENGINE_LUA_DIR) + std::string(file);
  int type;

  if (filename_is_absolute(file)) {
    if (o.debugging > 1)
      log_write(LOG_STDOUT, "%s: Trying absolute path %s\n", SCRIPT_ENGINE, file);
    Strncpy(path, file, path_len);
    return file_is_readable(file);
  }

  // lets look in <path>/scripts
  type = nmap_fetchfile(path, path_len, scripts_path.c_str());

  if (type == 0) {
    // current directory
    Strncpy(path, file, path_len);
    return file_is_readable(file);
  }

  return type;
}

static int fetchscript (lua_State *L)
{
  return nse_fetch(L, nse_fetchscript);
}

static int fetchfile_absolute (lua_State *L)
{
  return nse_fetch(L, nse_fetchfile_absolute);
}

static void open_cnse (lua_State *L)
{
  static const luaL_Reg nse[] = {
    {"fetchfile_absolute", fetchfile_absolute},
    {"fetchscript", fetchscript},
    {"key_was_pressed", key_was_pressed},
    {"scan_progress_meter", scan_progress_meter},
    {"timedOut", timedOut},
    {"startTimeOutClock", startTimeOutClock},
    {"stopTimeOutClock", stopTimeOutClock},
    {"ports", ports},
    {"script_set_output", script_set_output},
    {"host_set_output", host_set_output},
    {"port_set_output", port_set_output},
    {"log_write", l_log_write},
    {"xml_start_tag", l_xml_start_tag},
    {"xml_end_tag", l_xml_end_tag},
    {"xml_write_escaped", l_xml_write_escaped},
    {"xml_newline", l_xml_newline},
    {"protect_xml", l_protect_xml},
    {NULL, NULL}
  };

  luaL_newlib(L, nse);
  /* Add some other fields */
  nseU_setbfield(L, -1, "default", o.script);
  nseU_setbfield(L, -1, "scriptversion", o.scriptversion);
  nseU_setbfield(L, -1, "scriptupdatedb", o.scriptupdatedb);
  nseU_setbfield(L, -1, "scripthelp", o.scripthelp);
  nseU_setsfield(L, -1, "script_dbpath", SCRIPT_ENGINE_DATABASE);
  nseU_setsfield(L, -1, "scriptargs", o.scriptargs);
  nseU_setsfield(L, -1, "scriptargsfile", o.scriptargsfile);
  nseU_setsfield(L, -1, "NMAP_URL", NMAP_URL);
  nseU_setnfield(L, -1, "script_timeout", o.scripttimeout);

}

/* Global persistent Lua state used by the engine. */
static lua_State *L_NSE = NULL;

void ScriptResult::clear (void)
{
  if (o.debugging > 3)
    log_write(LOG_STDOUT, "ScriptResult::clear %d id %s\n", output_ref, get_id());
  luaL_unref(L_NSE, LUA_REGISTRYINDEX, output_ref);
  output_ref = LUA_NOREF;
  id = NULL;
}

void ScriptResult::set_output_tab (lua_State *L, int base)
{
  assert(lua_gettop(L) - base == 2); // we must have 3 args
  id = luaL_checkstring(L, base);
  lua_newtable(L);
  lua_insert(L, base);

  // string output
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);
  }
  else {
    if (!lua_isstring(L, -1)) {
      luaL_error(L, "String output is not a string");
      return;
    }
    lua_setfield(L, base, "str");
  }

  // structured output
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1);
  }
  else {
    lua_setfield(L, base, "tab");
  }

  // script id. We copy it here to ensure ScriptResult::id stays valid
  // (i.e. not garbage-collected)
  if (!lua_isstring(L, -1)) {
    luaL_error(L, "Script ID is not a string");
    return;
  }
  lua_setfield(L, base, "id");
  assert(lua_gettop(L) == base);
  output_ref = luaL_ref(L_NSE, LUA_REGISTRYINDEX);
  if (o.debugging > 3)
    log_write(LOG_STDOUT, "ScriptResult::set_output_tab %d id %s\n", output_ref, get_id());
}

static void format_obj(lua_State *L, int pos, std::string &output)
{
  pos = lua_absindex(L, pos);

  /* Look up the FORMAT_TABLE function from nse_main.lua and call it. */
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_FORMAT_TABLE);
  if (lua_isnil(L, -1)) {
    log_write(LOG_STDOUT, "%s: Cannot find function _R[\"%s\"] that should be in nse_main.lua\n",
      SCRIPT_ENGINE, NSE_FORMAT_TABLE);
    lua_pop(L, 1);
    return;
  }

  lua_pushvalue(L, pos);
  if (lua_pcall(L, 1, 1, 0) != 0) {
    if (o.debugging)
      log_write(LOG_STDOUT, "%s: Error in FORMAT_TABLE: %s\n", SCRIPT_ENGINE, lua_tostring(L, -1));
    lua_pop(L, 1);
    return;
  }

  size_t len = 0;
  const char *str = lua_tolstring(L, -1, &len);
  output.assign(str, len);
  lua_pop(L, 1);
}

std::string ScriptResult::get_output_str (void) const
{
  std::string output;

  assert(output_ref != LUA_NOREF);

  int out_obj = lua_rawgeti(L_NSE, LUA_REGISTRYINDEX, output_ref);
  assert(out_obj == LUA_TTABLE);

  /* Explicit string output? */
  if (LUA_TSTRING == lua_getfield(L_NSE, -1, "str")) {
    size_t len = 0;
    const char *str = lua_tolstring(L_NSE, -1, &len);
    output.assign(str, len);
  }
  else {
    lua_pop(L_NSE, 1); // get rid of whatever that was (nil)
    /* Auto-formatted table output? */
    if (LUA_TNIL != lua_getfield(L_NSE, -1, "tab"))
      format_obj(L_NSE, -1, output);
  }

  lua_pop(L_NSE, 2);
  return output;
}

ScriptResults *get_script_scan_results_obj (void)
{
  return &script_scan_results;
}

static void format_xml(lua_State *L, int pos)
{
  pos = lua_absindex(L, pos);

  /* Look up the FORMAT_XML function from nse_main.lua and call it. */
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_FORMAT_XML);
  if (lua_isnil(L, -1)) {
    log_write(LOG_STDOUT, "%s: Cannot find function _R[\"%s\"] that should be in nse_main.lua\n",
      SCRIPT_ENGINE, NSE_FORMAT_XML);
    lua_pop(L, 1);
    return;
  }

  lua_pushvalue(L, pos);
  if (lua_pcall(L, 1, 1, 0) != 0) {
    if (o.debugging)
      log_write(LOG_STDOUT, "%s: Error in FORMAT_XML: %s\n", SCRIPT_ENGINE, lua_tostring(L, -1));
    lua_pop(L, 1);
    return;
  }
}

void ScriptResult::write_xml() const
{
  std::string output_str;
  assert(output_ref != LUA_NOREF);
  assert(id != NULL);

  int out_obj = lua_rawgeti(L_NSE, LUA_REGISTRYINDEX, output_ref);
  assert(out_obj == LUA_TTABLE);

  out_obj = lua_gettop(L_NSE);

  xml_open_start_tag("script");
  xml_attribute("id", "%s", get_id());

  output_str = get_output_str();
  if (!output_str.empty())
    xml_attribute("output", "%s", protect_xml(output_str).c_str());
  else {
    error("Bug in %s: no string output.", get_id());
    xml_attribute("output", "%s", "");
  }

  /* Any table output? */
  if (LUA_TNIL != lua_getfield(L_NSE, out_obj, "tab")) {
    xml_close_start_tag();
    format_xml(L_NSE, -1);
    xml_end_tag();
  } else {
    xml_close_empty_tag();
  }

  lua_settop(L_NSE, out_obj - 1);
}

/* int panic (lua_State *L)
 *
 * Panic function set via lua_atpanic().
 */
static int panic (lua_State *L)
{
  const char *err = lua_tostring(L, 1);
  fatal("Unprotected error in Lua:\n%s\n", err);
  return 0;
}

static void set_nmap_libraries (lua_State *L)
{
  static const luaL_Reg libs[] = {
    {NSE_NMAPLIBNAME, luaopen_nmap},
    {NSE_DBLIBNAME, luaopen_db},
    {LFSLIBNAME, luaopen_lfs},
    {LPEGLIBNAME, luaopen_lpeg},
#ifdef HAVE_LIBSSH2
    {LIBSSH2LIBNAME, luaopen_libssh2},
#endif
#ifdef HAVE_OPENSSL
    {OPENSSLLIBNAME, luaopen_openssl},
#endif
#ifdef HAVE_LIBZ
    {NSE_ZLIBNAME, luaopen_zlib},
#endif
    {NULL, NULL}
  };

  for (int i = 0; libs[i].name; i++) {
    luaL_requiref(L, libs[i].name, libs[i].func, 1);
    lua_pop(L, 1);
  }
}

static int init_main (lua_State *L)
{
  char path[MAXPATHLEN];
  std::vector<std::string> *rules = (std::vector<std::string> *)
      lua_touserdata(L, 1);

  /* Load some basic libraries */
  luaL_openlibs(L);
  set_nmap_libraries(L);

  lua_newtable(L);
  lua_setfield(L, LUA_REGISTRYINDEX, NSE_CURRENT_HOSTS);

  if (nmap_fetchfile(path, sizeof(path), "nse_main.lua") != 1)
    luaL_error(L, "could not locate nse_main.lua");
  if (luaL_loadfile(L, path) != 0)
    luaL_error(L, "could not load nse_main.lua: %s", lua_tostring(L, -1));

  /* The first argument to the NSE Main Lua code is the private nse
   * library table which exposes certain necessary C functions to
   * the Lua engine.
   */
  open_cnse(L); /* first argument */

  /* The second argument is the script rules, including the
   * files/directories/categories passed as the userdata to this function.
   */
  lua_createtable(L, rules->size(), 0); /* second argument */
  for (std::vector<std::string>::iterator si = rules->begin(); si != rules->end(); si++)
    nseU_appendfstr(L, -1, "%s", si->c_str());

  lua_call(L, 2, 1); /* returns the NSE main function */

  lua_setfield(L, LUA_REGISTRYINDEX, NSE_MAIN);

  lua_pushinteger(L, o.min_parallelism);
  lua_setfield(L, LUA_REGISTRYINDEX, NSE_PARALLELISM);

  return 0;
}

static int run_main (lua_State *L)
{
  std::vector<Target *> *targets = (std::vector<Target*> *)
      lua_touserdata(L, 1);

  /* New host group */
  lua_newtable(L);
  lua_setfield(L, LUA_REGISTRYINDEX, NSE_CURRENT_HOSTS);

  lua_getfield(L, LUA_REGISTRYINDEX, NSE_MAIN);
  assert(lua_isfunction(L, -1));

  /* The first argument to the NSE main function is the list of targets.  This
   * has all the target names, 1-N, in a list.
   */
  lua_createtable(L, targets->size(), 0);
  int targets_table = lua_gettop(L);
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_CURRENT_HOSTS);
  int current_hosts = lua_gettop(L);
  for (std::vector<Target *>::iterator ti = targets->begin(); ti != targets->end(); ti++)
  {
    Target *target = (Target *) *ti;
    if (target->timedOut(NULL)) {
      continue;
    }
    const char *TargetName = target->TargetName();
    const char *targetipstr = target->targetipstr();
    lua_newtable(L);
    set_hostinfo(L, target);
    lua_rawseti(L, targets_table, lua_rawlen(L, targets_table) + 1);
    /* Index this Target in NSE_CURRENT_HOSTS under targetname and IP so we can
     * retrieve it later */
    if (TargetName != NULL && strcmp(TargetName, "") != 0) {
      lua_pushstring(L, TargetName);
      lua_pushlightuserdata(L, target);
      lua_rawset(L, current_hosts); /* add to NSE_CURRENT_HOSTS */
    }
    lua_pushstring(L, targetipstr);
    lua_pushlightuserdata(L, target);
    lua_rawset(L, current_hosts); /* add to NSE_CURRENT_HOSTS */
  }
  lua_settop(L, targets_table);

  /* Push script scan phase type. Second argument to NSE main function */
  switch (o.current_scantype)
  {
    case SCRIPT_PRE_SCAN:
      lua_pushliteral(L, NSE_PRE_SCAN);
      break;
    case SCRIPT_SCAN:
      lua_pushliteral(L, NSE_SCAN);
      break;
    case SCRIPT_POST_SCAN:
      lua_pushliteral(L, NSE_POST_SCAN);
      break;
    default:
      fatal("%s: failed to set the script scan phase.\n", SCRIPT_ENGINE);
  }

  lua_call(L, 2, 0);

  return 0;
}

/* int nse_yield (lua_State *L, int ctx, lua_CFunction k)  [-?, +?, e]
 *
 * This function will yield the running thread back to NSE, even across script
 * auxiliary coroutines. All NSE initiated yields must use this function. The
 * correct and only way to call is as a tail call:
 *   return nse_yield(L, 0, NULL);
 */
int nse_yield (lua_State *L, lua_KContext ctx, lua_KFunction k)
{
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_YIELD);
  lua_pushthread(L);
  lua_call(L, 1, 1); /* returns NSE_YIELD_VALUE */
  return lua_yieldk(L, 1, ctx, k); /* yield with NSE_YIELD_VALUE */
}

/* void nse_restore (lua_State *L, int number)             [-, -, e]
 *
 * Restore the thread 'L' back into the running NSE queue. 'number' is the
 * number of values on the stack to be passed when the thread is resumed. This
 * function may cause a panic due to extraordinary and unavoidable
 * circumstances.
 */
void nse_restore (lua_State *L, int number)
{
  luaL_checkstack(L, 5, "nse_restore: stack overflow");
  lua_pushthread(L);
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_WAITING_TO_RUNNING);
  lua_insert(L, -(number+2)); /* move WAITING_TO_RUNNING down below the args */
  lua_insert(L, -(number+1)); /* move thread above WAITING_TO_RUNNING */
  /* Call WAITING_TO_RUNNING (defined in nse_main.lua) on the thread and any
     other arguments. */
  if (lua_pcall(L, number+1, 0, 0) != 0)
    fatal("%s: WAITING_TO_RUNNING error!\n%s", __func__, lua_tostring(L, -1));
}

/* void nse_destructor (lua_State *L, char what)           [-(1|2), +0, e]
 *
 * This function adds (what = 'a') or removes (what = 'r') a destructor from
 * the Thread owning the running Lua thread (L). A destructor is called when
 * the thread finishes for any reason (including error). A unique key is used
 * to associate with the destructor so it is removable later.
 *
 * what == 'r', destructor key on stack
 * what == 'a', destructor key and destructor function on stack
 */
void nse_destructor (lua_State *L, char what)
{
  assert(what == 'a' || what == 'r');
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_DESTRUCTOR);
  lua_pushstring(L, what == 'a' ? "add" : "remove");
  lua_pushthread(L);
  if (what == 'a')
  {
    lua_pushvalue(L, -5); /* destructor key */
    lua_pushvalue(L, -5); /* destructor */
  }
  else
  {
    lua_pushvalue(L, -4); /* destructor key */
    lua_pushnil(L); /* no destructor, we are removing */
  }
  if (lua_pcall(L, 4, 0, 0) != 0)
    fatal("%s: NSE_DESTRUCTOR error!\n%s", __func__, lua_tostring(L, -1));
  lua_pop(L, what == 'a' ? 2 : 1);
}

/* void nse_base (lua_State *L)                             [-0, +1, e]
 *
 * Returns the base Lua thread (coroutine) for the running thread. The base
 * thread is resumed by NSE (runs the action function). Other coroutines being
 * used by the base thread may be in a chain of resumes, we use the base thread
 * as the "holder" of resources (for the Nsock binding in particular).
 */
void nse_base (lua_State *L)
{
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_BASE);
  lua_call(L, 0, 1); /* returns base thread */
}

/* void nse_selectedbyname (lua_State *L)                  [-0, +1, e]
 *
 * Returns a boolean signaling whether the running script was selected by name
 * on the command line (--script).
 */
void nse_selectedbyname (lua_State *L)
{
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_SELECTED_BY_NAME);
  if (lua_isnil(L, -1)) {
    lua_pushboolean(L, 0);
    lua_replace(L, -2);
  } else {
    lua_call(L, 0, 1);
  }
}

/* void nse_gettarget (lua_State *L)                  [-0, +1, -]
 *
 * Given the index to a string on the stack identifying the host, an ip or a
 * targetname (host name specified on the command line, see Target.h), returns
 * a lightuserdatum that points to the host's Target (see Target.h). If the
 * host cannot be found, nil is returned.
 */
void nse_gettarget (lua_State *L, int index)
{
  lua_pushvalue(L, index);
  lua_getfield(L, LUA_REGISTRYINDEX, NSE_CURRENT_HOSTS);
  lua_insert(L, -2);
  lua_rawget(L, -2);
  lua_replace(L, -2);
}

void open_nse (void)
{
  if (L_NSE == NULL)
  {
    /*
     Set the random seed value on behalf of scripts.  Since Lua uses the
     C rand and srand functions, which have a static seed for the entire
     program, we don't want scripts doing this themselves.
     */
    srand(get_random_uint());

    const lua_Number version = lua_version(NULL);
    double major = (version) / 100.0;
    double minor = fmod(version, 10.0);
    if (o.debugging >= 1)
      log_write(LOG_STDOUT, "%s: Using Lua %.0f.%.0f.\n", SCRIPT_ENGINE, major, minor);
    if (version < 504)
      fatal("%s: This version of NSE only works with Lua 5.4 or greater.", SCRIPT_ENGINE);
    if ((L_NSE = luaL_newstate()) == NULL)
      fatal("%s: failed to open a Lua state!", SCRIPT_ENGINE);
    lua_atpanic(L_NSE, panic);
    lua_settop(L_NSE, 0);

    lua_pushcfunction(L_NSE, nseU_traceback);
    lua_pushcfunction(L_NSE, init_main);
    lua_pushlightuserdata(L_NSE, &o.chosenScripts);
    if (lua_pcall(L_NSE, 1, 0, 1))
      fatal("%s: failed to initialize the script engine:\n%s\n", SCRIPT_ENGINE, lua_tostring(L_NSE, -1));
    lua_settop(L_NSE, 0);
  }
}

void script_scan (std::vector<Target *> &targets, stype scantype)
{
  o.current_scantype = scantype;

  assert(L_NSE != NULL);
  lua_settop(L_NSE, 0); /* clear the stack */

  lua_pushcfunction(L_NSE, nseU_traceback);
  lua_pushcfunction(L_NSE, run_main);
  lua_pushlightuserdata(L_NSE, &targets);
  if (lua_pcall(L_NSE, 1, 0, 1))
    error("%s: Script Engine Scan Aborted.\nAn error was thrown by the "
          "engine: %s", SCRIPT_ENGINE, lua_tostring(L_NSE, -1));
  lua_settop(L_NSE, 0);
}

void close_nse (void)
{
  if (L_NSE != NULL)
  {
    lua_close(L_NSE);
    L_NSE = NULL;
  }
}