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1 /* Unwinding of frames like gstack/pstack.
2    Copyright (C) 2013-2014 Red Hat, Inc.
3    This file is part of elfutils.
4 
5    This file is free software; you can redistribute it and/or modify
6    it under the terms of the GNU General Public License as published by
7    the Free Software Foundation; either version 3 of the License, or
8    (at your option) any later version.
9 
10    elfutils is distributed in the hope that it will be useful, but
11    WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13    GNU General Public License for more details.
14 
15    You should have received a copy of the GNU General Public License
16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
17 
18 #include <config.h>
19 #include <assert.h>
20 #include <argp.h>
21 #include <stdlib.h>
22 #include <inttypes.h>
23 #include <stdio.h>
24 #include <stdio_ext.h>
25 #include <string.h>
26 #include <locale.h>
27 #include <fcntl.h>
28 #include ELFUTILS_HEADER(dwfl)
29 
30 #include <dwarf.h>
31 #include <system.h>
32 #include <printversion.h>
33 
34 /* Name and version of program.  */
35 ARGP_PROGRAM_VERSION_HOOK_DEF = print_version;
36 
37 /* Bug report address.  */
38 ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT;
39 
40 /* non-printable argp options.  */
41 #define OPT_DEBUGINFO	0x100
42 #define OPT_COREFILE	0x101
43 
44 static bool show_activation = false;
45 static bool show_module = false;
46 static bool show_build_id = false;
47 static bool show_source = false;
48 static bool show_one_tid = false;
49 static bool show_quiet = false;
50 static bool show_raw = false;
51 static bool show_modules = false;
52 static bool show_debugname = false;
53 static bool show_inlines = false;
54 
55 static int maxframes = 256;
56 
57 struct frame
58 {
59   Dwarf_Addr pc;
60   bool isactivation;
61 };
62 
63 struct frames
64 {
65   int frames;
66   int allocated;
67   struct frame *frame;
68 };
69 
70 static Dwfl *dwfl = NULL;
71 static pid_t pid = 0;
72 static int core_fd = -1;
73 static Elf *core = NULL;
74 static const char *exec = NULL;
75 static char *debuginfo_path = NULL;
76 
77 static const Dwfl_Callbacks proc_callbacks =
78   {
79     .find_elf = dwfl_linux_proc_find_elf,
80     .find_debuginfo = dwfl_standard_find_debuginfo,
81     .debuginfo_path = &debuginfo_path,
82   };
83 
84 static const Dwfl_Callbacks core_callbacks =
85   {
86     .find_elf = dwfl_build_id_find_elf,
87     .find_debuginfo = dwfl_standard_find_debuginfo,
88     .debuginfo_path = &debuginfo_path,
89   };
90 
91 #ifdef USE_DEMANGLE
92 static size_t demangle_buffer_len = 0;
93 static char *demangle_buffer = NULL;
94 #endif
95 
96 /* Whether any frames have been shown at all.  Determines exit status.  */
97 static bool frames_shown = false;
98 
99 /* Program exit codes. All frames shown without any errors is GOOD.
100    Some frames shown with some non-fatal errors is an ERROR.  A fatal
101    error or no frames shown at all is BAD.  A command line USAGE exit
102    is generated by argp_error.  */
103 #define EXIT_OK     0
104 #define EXIT_ERROR  1
105 #define EXIT_BAD    2
106 #define EXIT_USAGE 64
107 
108 static int
get_addr_width(Dwfl_Module * mod)109 get_addr_width (Dwfl_Module *mod)
110 {
111   // Try to find the address wide if possible.
112   static int width = 0;
113   if (width == 0 && mod)
114     {
115       Dwarf_Addr bias;
116       Elf *elf = dwfl_module_getelf (mod, &bias);
117       if (elf)
118         {
119 	  GElf_Ehdr ehdr_mem;
120 	  GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);
121 	  if (ehdr)
122 	    width = ehdr->e_ident[EI_CLASS] == ELFCLASS32 ? 8 : 16;
123 	}
124     }
125   if (width == 0)
126     width = 16;
127 
128   return width;
129 }
130 
131 static int
module_callback(Dwfl_Module * mod,void ** userdata,const char * name,Dwarf_Addr start,void * arg)132 module_callback (Dwfl_Module *mod, void **userdata __attribute__((unused)),
133 		 const char *name, Dwarf_Addr start,
134 		 void *arg __attribute__((unused)))
135 {
136   /* Forces resolving of main elf and debug files. */
137   Dwarf_Addr bias;
138   Elf *elf = dwfl_module_getelf (mod, &bias);
139   Dwarf *dwarf = dwfl_module_getdwarf (mod, &bias);
140 
141   Dwarf_Addr end;
142   const char *mainfile;
143   const char *debugfile;
144   const char *modname = dwfl_module_info (mod, NULL, NULL, &end, NULL,
145                                           NULL, &mainfile, &debugfile);
146   assert (strcmp (modname, name) == 0);
147 
148   int width = get_addr_width (mod);
149   printf ("0x%0*" PRIx64 "-0x%0*" PRIx64 " %s\n",
150 	  width, start, width, end, basename (name));
151 
152   const unsigned char *id;
153   GElf_Addr id_vaddr;
154   int id_len = dwfl_module_build_id (mod, &id, &id_vaddr);
155   if (id_len > 0)
156     {
157       printf ("  [");
158       do
159 	printf ("%02" PRIx8, *id++);
160       while (--id_len > 0);
161       printf ("]\n");
162     }
163 
164   if (elf != NULL)
165     printf ("  %s\n", mainfile != NULL ? mainfile : "-");
166   if (dwarf != NULL)
167     printf ("  %s\n", debugfile != NULL ? debugfile : "-");
168 
169   return DWARF_CB_OK;
170 }
171 
172 static int
frame_callback(Dwfl_Frame * state,void * arg)173 frame_callback (Dwfl_Frame *state, void *arg)
174 {
175   struct frames *frames = (struct frames *) arg;
176   int nr = frames->frames;
177   if (! dwfl_frame_pc (state, &frames->frame[nr].pc,
178 		       &frames->frame[nr].isactivation))
179     return -1;
180 
181   frames->frames++;
182   if (frames->frames == maxframes)
183     return DWARF_CB_ABORT;
184 
185   if (frames->frames == frames->allocated)
186     {
187       frames->allocated *= 2;
188       frames->frame = realloc (frames->frame,
189 			       sizeof (struct frame) * frames->allocated);
190       if (frames->frame == NULL)
191 	error (EXIT_BAD, errno, "realloc frames.frame");
192     }
193 
194   return DWARF_CB_OK;
195 }
196 
197 static const char*
die_name(Dwarf_Die * die)198 die_name (Dwarf_Die *die)
199 {
200   Dwarf_Attribute attr;
201   const char *name;
202   name = dwarf_formstring (dwarf_attr_integrate (die,
203 						 DW_AT_MIPS_linkage_name,
204 						 &attr)
205 			   ?: dwarf_attr_integrate (die,
206 						    DW_AT_linkage_name,
207 						    &attr));
208   if (name == NULL)
209     name = dwarf_diename (die);
210 
211   return name;
212 }
213 
214 static void
print_frame(int nr,Dwarf_Addr pc,bool isactivation,Dwarf_Addr pc_adjusted,Dwfl_Module * mod,const char * symname,Dwarf_Die * cudie,Dwarf_Die * die)215 print_frame (int nr, Dwarf_Addr pc, bool isactivation,
216 	     Dwarf_Addr pc_adjusted, Dwfl_Module *mod,
217 	     const char *symname, Dwarf_Die *cudie,
218 	     Dwarf_Die *die)
219 {
220   int width = get_addr_width (mod);
221   printf ("#%-2u 0x%0*" PRIx64, nr, width, (uint64_t) pc);
222 
223   if (show_activation)
224     printf ("%4s", ! isactivation ? "- 1" : "");
225 
226   if (symname != NULL)
227     {
228 #ifdef USE_DEMANGLE
229       // Require GNU v3 ABI by the "_Z" prefix.
230       if (! show_raw && symname[0] == '_' && symname[1] == 'Z')
231 	{
232 	  int status = -1;
233 	  char *dsymname = __cxa_demangle (symname, demangle_buffer,
234 					   &demangle_buffer_len, &status);
235 	  if (status == 0)
236 	    symname = demangle_buffer = dsymname;
237 	}
238 #endif
239       printf (" %s", symname);
240     }
241 
242   const char* fname;
243   Dwarf_Addr start;
244   fname = dwfl_module_info(mod, NULL, &start,
245 			   NULL, NULL, NULL, NULL, NULL);
246   if (show_module)
247     {
248       if (fname != NULL)
249 	printf (" - %s", fname);
250     }
251 
252   if (show_build_id)
253     {
254       const unsigned char *id;
255       GElf_Addr id_vaddr;
256       int id_len = dwfl_module_build_id (mod, &id, &id_vaddr);
257       if (id_len > 0)
258 	{
259 	  printf ("\n    [");
260 	  do
261 	    printf ("%02" PRIx8, *id++);
262 	  while (--id_len > 0);
263 	  printf ("]@0x%0" PRIx64 "+0x%" PRIx64,
264 		  start, pc_adjusted - start);
265 	}
266     }
267 
268   if (show_source)
269     {
270       int line, col;
271       const char* sname;
272       line = col = -1;
273       sname = NULL;
274       if (die != NULL)
275 	{
276 	  Dwarf_Files *files;
277 	  if (dwarf_getsrcfiles (cudie, &files, NULL) == 0)
278 	    {
279 	      Dwarf_Attribute attr;
280 	      Dwarf_Word val;
281 	      if (dwarf_formudata (dwarf_attr (die, DW_AT_call_file, &attr),
282 				   &val) == 0)
283 		{
284 		  sname = dwarf_filesrc (files, val, NULL, NULL);
285 		  if (dwarf_formudata (dwarf_attr (die, DW_AT_call_line,
286 						   &attr), &val) == 0)
287 		    {
288 		      line = val;
289 		      if (dwarf_formudata (dwarf_attr (die, DW_AT_call_column,
290 						       &attr), &val) == 0)
291 			col = val;
292 		    }
293 		}
294 	    }
295 	}
296       else
297 	{
298 	  Dwfl_Line *lineobj = dwfl_module_getsrc(mod, pc_adjusted);
299 	  if (lineobj)
300 	    sname = dwfl_lineinfo (lineobj, NULL, &line, &col, NULL, NULL);
301 	}
302 
303       if (sname != NULL)
304 	{
305 	  printf ("\n    %s", sname);
306 	  if (line > 0)
307 	    {
308 	      printf (":%d", line);
309 	      if (col > 0)
310 		printf (":%d", col);
311 	    }
312 	}
313     }
314   printf ("\n");
315 }
316 
317 static void
print_inline_frames(int * nr,Dwarf_Addr pc,bool isactivation,Dwarf_Addr pc_adjusted,Dwfl_Module * mod,const char * symname,Dwarf_Die * cudie,Dwarf_Die * die)318 print_inline_frames (int *nr, Dwarf_Addr pc, bool isactivation,
319 		     Dwarf_Addr pc_adjusted, Dwfl_Module *mod,
320 		     const char *symname, Dwarf_Die *cudie, Dwarf_Die *die)
321 {
322   Dwarf_Die *scopes = NULL;
323   int nscopes = dwarf_getscopes_die (die, &scopes);
324   if (nscopes > 0)
325     {
326       /* scopes[0] == die, the lowest level, for which we already have
327 	 the name.  This is the actual source location where it
328 	 happened.  */
329       print_frame ((*nr)++, pc, isactivation, pc_adjusted, mod, symname,
330 		   NULL, NULL);
331 
332       /* last_scope is the source location where the next frame/function
333 	 call was done. */
334       Dwarf_Die *last_scope = &scopes[0];
335       for (int i = 1; i < nscopes && (maxframes == 0 || *nr < maxframes); i++)
336 	{
337 	  Dwarf_Die *scope = &scopes[i];
338 	  int tag = dwarf_tag (scope);
339 	  if (tag != DW_TAG_inlined_subroutine
340 	      && tag != DW_TAG_entry_point
341 	      && tag != DW_TAG_subprogram)
342 	    continue;
343 
344 	  symname = die_name (scope);
345 	  print_frame ((*nr)++, pc, isactivation, pc_adjusted, mod, symname,
346 		       cudie, last_scope);
347 
348 	  /* Found the "top-level" in which everything was inlined?  */
349 	  if (tag == DW_TAG_subprogram)
350 	    break;
351 
352 	  last_scope = scope;
353 	}
354     }
355   free (scopes);
356 }
357 
358 static void
print_frames(struct frames * frames,pid_t tid,int dwflerr,const char * what)359 print_frames (struct frames *frames, pid_t tid, int dwflerr, const char *what)
360 {
361   if (frames->frames > 0)
362     frames_shown = true;
363 
364   printf ("TID %lld:\n", (long long) tid);
365   int frame_nr = 0;
366   for (int nr = 0; nr < frames->frames && (maxframes == 0
367 					   || frame_nr < maxframes); nr++)
368     {
369       Dwarf_Addr pc = frames->frame[nr].pc;
370       bool isactivation = frames->frame[nr].isactivation;
371       Dwarf_Addr pc_adjusted = pc - (isactivation ? 0 : 1);
372 
373       /* Get PC->SYMNAME.  */
374       Dwfl_Module *mod = dwfl_addrmodule (dwfl, pc_adjusted);
375       const char *symname = NULL;
376       Dwarf_Die die_mem;
377       Dwarf_Die *die = NULL;
378       Dwarf_Die *cudie = NULL;
379       if (mod && ! show_quiet)
380 	{
381 	  if (show_debugname)
382 	    {
383 	      Dwarf_Addr bias = 0;
384 	      Dwarf_Die *scopes = NULL;
385 	      cudie = dwfl_module_addrdie (mod, pc_adjusted, &bias);
386 	      int nscopes = dwarf_getscopes (cudie, pc_adjusted - bias,
387 					     &scopes);
388 
389 	      /* Find the first function-like DIE with a name in scope.  */
390 	      for (int i = 0; symname == NULL && i < nscopes; i++)
391 		{
392 		  Dwarf_Die *scope = &scopes[i];
393 		  int tag = dwarf_tag (scope);
394 		  if (tag == DW_TAG_subprogram
395 		      || tag == DW_TAG_inlined_subroutine
396 		      || tag == DW_TAG_entry_point)
397 		    symname = die_name (scope);
398 
399 		  if (symname != NULL)
400 		    {
401 		      die_mem = *scope;
402 		      die = &die_mem;
403 		    }
404 		}
405 	      free (scopes);
406 	    }
407 
408 	  if (symname == NULL)
409 	    symname = dwfl_module_addrname (mod, pc_adjusted);
410 	}
411 
412       if (show_inlines && die != NULL)
413 	print_inline_frames (&frame_nr, pc, isactivation, pc_adjusted, mod,
414 			     symname, cudie, die);
415       else
416 	print_frame (frame_nr++, pc, isactivation, pc_adjusted, mod, symname,
417 		     NULL, NULL);
418     }
419 
420   if (frames->frames > 0 && frame_nr == maxframes)
421     error (0, 0, "tid %lld: shown max number of frames "
422 	   "(%d, use -n 0 for unlimited)", (long long) tid, maxframes);
423   else if (dwflerr != 0)
424     {
425       if (frames->frames > 0)
426 	{
427 	  unsigned nr = frames->frames - 1;
428 	  Dwarf_Addr pc = frames->frame[nr].pc;
429 	  bool isactivation = frames->frame[nr].isactivation;
430 	  Dwarf_Addr pc_adjusted = pc - (isactivation ? 0 : 1);
431 	  Dwfl_Module *mod = dwfl_addrmodule (dwfl, pc_adjusted);
432 	  const char *mainfile = NULL;
433 	  const char *modname = dwfl_module_info (mod, NULL, NULL, NULL, NULL,
434 						  NULL, &mainfile, NULL);
435 	  if (modname == NULL || modname[0] == '\0')
436 	    {
437 	      if (mainfile != NULL)
438 		modname = mainfile;
439 	      else
440 		modname = "<unknown>";
441 	    }
442 	  error (0, 0, "%s tid %lld at 0x%" PRIx64 " in %s: %s", what,
443 		 (long long) tid, pc_adjusted, modname, dwfl_errmsg (dwflerr));
444 	}
445       else
446 	error (0, 0, "%s tid %lld: %s", what, (long long) tid,
447 	       dwfl_errmsg (dwflerr));
448     }
449 }
450 
451 static int
thread_callback(Dwfl_Thread * thread,void * thread_arg)452 thread_callback (Dwfl_Thread *thread, void *thread_arg)
453 {
454   struct frames *frames = (struct frames *) thread_arg;
455   pid_t tid = dwfl_thread_tid (thread);
456   int err = 0;
457   frames->frames = 0;
458   switch (dwfl_thread_getframes (thread, frame_callback, thread_arg))
459     {
460     case DWARF_CB_OK:
461     case DWARF_CB_ABORT:
462       break;
463     case -1:
464       err = dwfl_errno ();
465       break;
466     default:
467       abort ();
468     }
469   print_frames (frames, tid, err, "dwfl_thread_getframes");
470   return DWARF_CB_OK;
471 }
472 
473 static error_t
parse_opt(int key,char * arg,struct argp_state * state)474 parse_opt (int key, char *arg __attribute__ ((unused)),
475 	   struct argp_state *state)
476 {
477   switch (key)
478     {
479     case 'p':
480       pid = atoi (arg);
481       if (pid == 0)
482 	argp_error (state, N_("-p PID should be a positive process id."));
483       break;
484 
485     case OPT_COREFILE:
486       core_fd = open (arg, O_RDONLY);
487       if (core_fd < 0)
488 	error (EXIT_BAD, errno, N_("Cannot open core file '%s'"), arg);
489       elf_version (EV_CURRENT);
490       core = elf_begin (core_fd, ELF_C_READ_MMAP, NULL);
491       if (core == NULL)
492 	error (EXIT_BAD, 0, "core '%s' elf_begin: %s", arg, elf_errmsg(-1));
493       break;
494 
495     case 'e':
496       exec = arg;
497       break;
498 
499     case OPT_DEBUGINFO:
500       debuginfo_path = arg;
501       break;
502 
503     case 'm':
504       show_module = true;
505       break;
506 
507     case 's':
508       show_source = true;
509       break;
510 
511     case 'a':
512       show_activation = true;
513       break;
514 
515     case 'd':
516       show_debugname = true;
517       break;
518 
519     case 'i':
520       show_inlines = show_debugname = true;
521       break;
522 
523     case 'v':
524       show_activation = show_source = show_module = show_debugname = true;
525       show_inlines = true;
526       break;
527 
528     case 'b':
529       show_build_id = true;
530       break;
531 
532     case 'q':
533       show_quiet = true;
534       break;
535 
536     case 'r':
537       show_raw = true;
538       break;
539 
540     case '1':
541       show_one_tid = true;
542       break;
543 
544     case 'n':
545       maxframes = atoi (arg);
546       if (maxframes < 0)
547 	{
548 	  argp_error (state, N_("-n MAXFRAMES should be 0 or higher."));
549 	  return EINVAL;
550 	}
551       break;
552 
553     case 'l':
554       show_modules = true;
555       break;
556 
557     case ARGP_KEY_END:
558       if (core == NULL && exec != NULL)
559 	argp_error (state,
560 		    N_("-e EXEC needs a core given by --core."));
561 
562       if (pid == 0 && show_one_tid == true)
563 	argp_error (state,
564 		    N_("-1 needs a thread id given by -p."));
565 
566       if ((pid == 0 && core == NULL) || (pid != 0 && core != NULL))
567 	argp_error (state,
568 		    N_("One of -p PID or --core COREFILE should be given."));
569 
570       if (pid != 0)
571 	{
572 	  dwfl = dwfl_begin (&proc_callbacks);
573 	  if (dwfl == NULL)
574 	    error (EXIT_BAD, 0, "dwfl_begin: %s", dwfl_errmsg (-1));
575 
576 	  int err = dwfl_linux_proc_report (dwfl, pid);
577 	  if (err < 0)
578 	    error (EXIT_BAD, 0, "dwfl_linux_proc_report pid %lld: %s",
579 		   (long long) pid, dwfl_errmsg (-1));
580 	  else if (err > 0)
581 	    error (EXIT_BAD, err, "dwfl_linux_proc_report pid %lld",
582 		   (long long) pid);
583 	}
584 
585       if (core != NULL)
586 	{
587 	  dwfl = dwfl_begin (&core_callbacks);
588 	  if (dwfl == NULL)
589 	    error (EXIT_BAD, 0, "dwfl_begin: %s", dwfl_errmsg (-1));
590 	  if (dwfl_core_file_report (dwfl, core, exec) < 0)
591 	    error (EXIT_BAD, 0, "dwfl_core_file_report: %s", dwfl_errmsg (-1));
592 	}
593 
594       if (dwfl_report_end (dwfl, NULL, NULL) != 0)
595 	error (EXIT_BAD, 0, "dwfl_report_end: %s", dwfl_errmsg (-1));
596 
597       if (pid != 0)
598 	{
599 	  int err = dwfl_linux_proc_attach (dwfl, pid, false);
600 	  if (err < 0)
601 	    error (EXIT_BAD, 0, "dwfl_linux_proc_attach pid %lld: %s",
602 		   (long long) pid, dwfl_errmsg (-1));
603 	  else if (err > 0)
604 	    error (EXIT_BAD, err, "dwfl_linux_proc_attach pid %lld",
605 		   (long long) pid);
606 	}
607 
608       if (core != NULL)
609 	{
610 	  if (dwfl_core_file_attach (dwfl, core) < 0)
611 	    error (EXIT_BAD, 0, "dwfl_core_file_attach: %s", dwfl_errmsg (-1));
612 	}
613 
614       /* Makes sure we are properly attached.  */
615       if (dwfl_pid (dwfl) < 0)
616 	error (EXIT_BAD, 0, "dwfl_pid: %s\n", dwfl_errmsg (-1));
617       break;
618 
619     default:
620       return ARGP_ERR_UNKNOWN;
621     }
622   return 0;
623 }
624 
625 int
main(int argc,char ** argv)626 main (int argc, char **argv)
627 {
628   /* We use no threads here which can interfere with handling a stream.  */
629   __fsetlocking (stdin, FSETLOCKING_BYCALLER);
630   __fsetlocking (stdout, FSETLOCKING_BYCALLER);
631   __fsetlocking (stderr, FSETLOCKING_BYCALLER);
632 
633   /* Set locale.  */
634   (void) setlocale (LC_ALL, "");
635 
636   const struct argp_option options[] =
637     {
638       { NULL, 0, NULL, 0, N_("Input selection options:"), 0 },
639       { "pid", 'p', "PID", 0,
640 	N_("Show stack of process PID"), 0 },
641       { "core", OPT_COREFILE, "COREFILE", 0,
642 	N_("Show stack found in COREFILE"), 0 },
643       {  "executable", 'e', "EXEC", 0, N_("(optional) EXECUTABLE that produced COREFILE"), 0 },
644       { "debuginfo-path", OPT_DEBUGINFO, "PATH", 0,
645 	N_("Search path for separate debuginfo files"), 0 },
646 
647       { NULL, 0, NULL, 0, N_("Output selection options:"), 0 },
648       { "activation",  'a', NULL, 0,
649 	N_("Additionally show frame activation"), 0 },
650       { "debugname",  'd', NULL, 0,
651 	N_("Additionally try to lookup DWARF debuginfo name for frame address"),
652 	0 },
653       { "inlines",  'i', NULL, 0,
654 	N_("Additionally show inlined function frames using DWARF debuginfo if available (implies -d)"), 0 },
655       { "module",  'm', NULL, 0,
656 	N_("Additionally show module file information"), 0 },
657       { "source",  's', NULL, 0,
658 	N_("Additionally show source file information"), 0 },
659       { "verbose", 'v', NULL, 0,
660 	N_("Show all additional information (activation, debugname, inlines, module and source)"), 0 },
661       { "quiet", 'q', NULL, 0,
662 	N_("Do not resolve address to function symbol name"), 0 },
663       { "raw", 'r', NULL, 0,
664 	N_("Show raw function symbol names, do not try to demangle names"), 0 },
665       { "build-id",  'b', NULL, 0,
666 	N_("Show module build-id, load address and pc offset"), 0 },
667       { NULL, '1', NULL, 0,
668 	N_("Show the backtrace of only one thread"), 0 },
669       { NULL, 'n', "MAXFRAMES", 0,
670 	N_("Show at most MAXFRAMES per thread (default 256, use 0 for unlimited)"), 0 },
671       { "list-modules", 'l', NULL, 0,
672 	N_("Show module memory map with build-id, elf and debug files detected"), 0 },
673       { NULL, 0, NULL, 0, NULL, 0 }
674     };
675 
676   const struct argp argp =
677     {
678       .options = options,
679       .parser = parse_opt,
680       .doc = N_("Print a stack for each thread in a process or core file.\n\
681 \n\
682 Program exits with return code 0 if all frames were shown without \
683 any errors.  If some frames were shown, but there were some non-fatal \
684 errors, possibly causing an incomplete backtrace, the program exits \
685 with return code 1.  If no frames could be shown, or a fatal error \
686 occured the program exits with return code 2.  If the program was \
687 invoked with bad or missing arguments it will exit with return code 64.")
688     };
689 
690   argp_parse (&argp, argc, argv, 0, NULL, NULL);
691 
692   if (show_modules)
693     {
694       printf ("PID %lld - %s module memory map\n", (long long) dwfl_pid (dwfl),
695 	      pid != 0 ? "process" : "core");
696       if (dwfl_getmodules (dwfl, module_callback, NULL, 0) != 0)
697 	error (EXIT_BAD, 0, "dwfl_getmodules: %s", dwfl_errmsg (-1));
698     }
699 
700   struct frames frames;
701   /* When maxframes is zero, then 2048 is just the initial allocation
702      that will be increased using realloc in framecallback ().  */
703   frames.allocated = maxframes == 0 ? 2048 : maxframes;
704   frames.frames = 0;
705   frames.frame = malloc (sizeof (struct frame) * frames.allocated);
706   if (frames.frame == NULL)
707     error (EXIT_BAD, errno, "malloc frames.frame");
708 
709   if (show_one_tid)
710     {
711       int err = 0;
712       switch (dwfl_getthread_frames (dwfl, pid, frame_callback, &frames))
713 	{
714 	case DWARF_CB_OK:
715 	case DWARF_CB_ABORT:
716 	  break;
717 	case -1:
718 	  err = dwfl_errno ();
719 	  break;
720 	default:
721 	  abort ();
722 	}
723       print_frames (&frames, pid, err, "dwfl_getthread_frames");
724     }
725   else
726     {
727       printf ("PID %lld - %s\n", (long long) dwfl_pid (dwfl),
728 	      pid != 0 ? "process" : "core");
729       switch (dwfl_getthreads (dwfl, thread_callback, &frames))
730 	{
731 	case DWARF_CB_OK:
732 	case DWARF_CB_ABORT:
733 	  break;
734 	case -1:
735 	  error (0, 0, "dwfl_getthreads: %s", dwfl_errmsg (-1));
736 	  break;
737 	default:
738 	  abort ();
739 	}
740     }
741   free (frames.frame);
742   dwfl_end (dwfl);
743 
744   if (core != NULL)
745     elf_end (core);
746 
747   if (core_fd != -1)
748     close (core_fd);
749 
750 #ifdef USE_DEMANGLE
751   free (demangle_buffer);
752 #endif
753 
754   if (! frames_shown)
755     error (EXIT_BAD, 0, N_("Couldn't show any frames."));
756 
757   return error_message_count != 0 ? EXIT_ERROR : EXIT_OK;
758 }
759