/* Unwinding of frames like gstack/pstack.

   Copyright (C) 2013-2014 Red Hat, Inc.

   This file is part of elfutils.

   This file is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   elfutils 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include <config.h>

#include <assert.h>

#include <argp.h>

#include <stdlib.h>

#include <inttypes.h>

#include <stdio.h>

#include <stdio_ext.h>

#include <string.h>

#include <locale.h>

#include <fcntl.h>

#include ELFUTILS_HEADER(dwfl)

#include <dwarf.h>

#include <system.h>

#include <printversion.h>

/* Name and version of program.  */

ARGP_PROGRAM_VERSION_HOOK_DEF = print_version;

/* Bug report address.  */

ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT;

/* non-printable argp options.  */

#define OPT_DEBUGINFO	0x100

#define OPT_COREFILE	0x101

static bool show_activation = false;

static bool show_module = false;

static bool show_build_id = false;

static bool show_source = false;

static bool show_one_tid = false;

static bool show_quiet = false;

static bool show_raw = false;

static bool show_modules = false;

static bool show_debugname = false;

static bool show_inlines = false;

static int maxframes = 256;

struct frame

{

  Dwarf_Addr pc;

  bool isactivation;

};

struct frames

{

  int frames;

  int allocated;

  struct frame *frame;

};

static Dwfl *dwfl = NULL;

static pid_t pid = 0;

static int core_fd = -1;

static Elf *core = NULL;

static const char *exec = NULL;

static char *debuginfo_path = NULL;

static const Dwfl_Callbacks proc_callbacks =

  {

    .find_elf = dwfl_linux_proc_find_elf,

    .find_debuginfo = dwfl_standard_find_debuginfo,

    .debuginfo_path = &debuginfo_path,

  };

static const Dwfl_Callbacks core_callbacks =

  {

    .find_elf = dwfl_build_id_find_elf,

    .find_debuginfo = dwfl_standard_find_debuginfo,

    .debuginfo_path = &debuginfo_path,

  };

#ifdef USE_DEMANGLE

static size_t demangle_buffer_len = 0;

static char *demangle_buffer = NULL;

#endif

/* Whether any frames have been shown at all.  Determines exit status.  */

static bool frames_shown = false;

/* Program exit codes. All frames shown without any errors is GOOD.

   Some frames shown with some non-fatal errors is an ERROR.  A fatal

   error or no frames shown at all is BAD.  A command line USAGE exit

   is generated by argp_error.  */

#define EXIT_OK     0

#define EXIT_ERROR  1

#define EXIT_BAD    2

#define EXIT_USAGE 64

static int

get_addr_width (Dwfl_Module *mod)

{

  // Try to find the address wide if possible.

  static int width = 0;

  if (width == 0 && mod)

    {

      Dwarf_Addr bias;

      Elf *elf = dwfl_module_getelf (mod, &bias);

      if (elf)

        {

	  GElf_Ehdr ehdr_mem;

	  GElf_Ehdr *ehdr = gelf_getehdr (elf, &ehdr_mem);

	  if (ehdr)

	    width = ehdr->e_ident[EI_CLASS] == ELFCLASS32 ? 8 : 16;

	}

    }

  if (width == 0)

    width = 16;

  return width;

}

static int

module_callback (Dwfl_Module *mod, void **userdata __attribute__((unused)),

		 const char *name, Dwarf_Addr start,

		 void *arg __attribute__((unused)))

{

  /* Forces resolving of main elf and debug files. */

  Dwarf_Addr bias;

  Elf *elf = dwfl_module_getelf (mod, &bias);

  Dwarf *dwarf = dwfl_module_getdwarf (mod, &bias);

  Dwarf_Addr end;

  const char *mainfile;

  const char *debugfile;

  const char *modname = dwfl_module_info (mod, NULL, NULL, &end, NULL,

                                          NULL, &mainfile, &debugfile);

  assert (strcmp (modname, name) == 0);

  int width = get_addr_width (mod);

  printf ("0x%0*" PRIx64 "-0x%0*" PRIx64 " %s\n",

	  width, start, width, end, basename (name));

  const unsigned char *id;

  GElf_Addr id_vaddr;

  int id_len = dwfl_module_build_id (mod, &id, &id_vaddr);

  if (id_len > 0)

    {

      printf ("  [");

      do

	printf ("%02" PRIx8, *id++);

      while (--id_len > 0);

      printf ("]\n");

    }

  if (elf != NULL)

    printf ("  %s\n", mainfile != NULL ? mainfile : "-");

  if (dwarf != NULL)

    printf ("  %s\n", debugfile != NULL ? debugfile : "-");

  return DWARF_CB_OK;

}

static int

frame_callback (Dwfl_Frame *state, void *arg)

{

  struct frames *frames = (struct frames *) arg;

  int nr = frames->frames;

  if (! dwfl_frame_pc (state, &frames->frame[nr].pc,

		       &frames->frame[nr].isactivation))

    return -1;

  frames->frames++;

  if (frames->frames == maxframes)

    return DWARF_CB_ABORT;

  if (frames->frames == frames->allocated)

    {

      frames->allocated *= 2;

      frames->frame = realloc (frames->frame,

			       sizeof (struct frame) * frames->allocated);

      if (frames->frame == NULL)

	error (EXIT_BAD, errno, "realloc frames.frame");

    }

  return DWARF_CB_OK;

}

static const char*

die_name (Dwarf_Die *die)

{

  Dwarf_Attribute attr;

  const char *name;

  name = dwarf_formstring (dwarf_attr_integrate (die,

						 DW_AT_MIPS_linkage_name,

						 &attr)

			   ?: dwarf_attr_integrate (die,

						    DW_AT_linkage_name,

						    &attr));

  if (name == NULL)

    name = dwarf_diename (die);

  return name;

}

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)

{

  int width = get_addr_width (mod);

  printf ("#%-2u 0x%0*" PRIx64, nr, width, (uint64_t) pc);

  if (show_activation)

    printf ("%4s", ! isactivation ? "- 1" : "");

  if (symname != NULL)

    {

#ifdef USE_DEMANGLE

      // Require GNU v3 ABI by the "_Z" prefix.

      if (! show_raw && symname[0] == '_' && symname[1] == 'Z')

	{

	  int status = -1;

	  char *dsymname = __cxa_demangle (symname, demangle_buffer,

					   &demangle_buffer_len, &status);

	  if (status == 0)

	    symname = demangle_buffer = dsymname;

	}

#endif

      printf (" %s", symname);

    }

  const char* fname;

  Dwarf_Addr start;

  fname = dwfl_module_info(mod, NULL, &start,

			   NULL, NULL, NULL, NULL, NULL);

  if (show_module)

    {

      if (fname != NULL)

	printf (" - %s", fname);

    }

  if (show_build_id)

    {

      const unsigned char *id;

      GElf_Addr id_vaddr;

      int id_len = dwfl_module_build_id (mod, &id, &id_vaddr);

      if (id_len > 0)

	{

	  printf ("\n    [");

	  do

	    printf ("%02" PRIx8, *id++);

	  while (--id_len > 0);

	  printf ("]@0x%0" PRIx64 "+0x%" PRIx64,

		  start, pc_adjusted - start);

	}

    }

  if (show_source)

    {

      int line, col;

      const char* sname;

      line = col = -1;

      sname = NULL;

      if (die != NULL)

	{

	  Dwarf_Files *files;

	  if (dwarf_getsrcfiles (cudie, &files, NULL) == 0)

	    {

	      Dwarf_Attribute attr;

	      Dwarf_Word val;

	      if (dwarf_formudata (dwarf_attr (die, DW_AT_call_file, &attr),

				   &val) == 0)

		{

		  sname = dwarf_filesrc (files, val, NULL, NULL);

		  if (dwarf_formudata (dwarf_attr (die, DW_AT_call_line,

						   &attr), &val) == 0)

		    {

		      line = val;

		      if (dwarf_formudata (dwarf_attr (die, DW_AT_call_column,

						       &attr), &val) == 0)

			col = val;

		    }

		}

	    }

	}

      else

	{

	  Dwfl_Line *lineobj = dwfl_module_getsrc(mod, pc_adjusted);

	  if (lineobj)

	    sname = dwfl_lineinfo (lineobj, NULL, &line, &col, NULL, NULL);

	}

      if (sname != NULL)

	{

	  printf ("\n    %s", sname);

	  if (line > 0)

	    {

	      printf (":%d", line);

	      if (col > 0)

		printf (":%d", col);

	    }

	}

    }

  printf ("\n");

}

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)

{

  Dwarf_Die *scopes = NULL;

  int nscopes = dwarf_getscopes_die (die, &scopes);

  if (nscopes > 0)

    {

      /* scopes[0] == die, the lowest level, for which we already have

	 the name.  This is the actual source location where it

	 happened.  */

      print_frame ((*nr)++, pc, isactivation, pc_adjusted, mod, symname,

		   NULL, NULL);

      /* last_scope is the source location where the next frame/function

	 call was done. */

      Dwarf_Die *last_scope = &scopes[0];

      for (int i = 1; i < nscopes && (maxframes == 0 || *nr < maxframes); i++)

	{

	  Dwarf_Die *scope = &scopes[i];

	  int tag = dwarf_tag (scope);

	  if (tag != DW_TAG_inlined_subroutine

	      && tag != DW_TAG_entry_point

	      && tag != DW_TAG_subprogram)

	    continue;

	  symname = die_name (scope);

	  print_frame ((*nr)++, pc, isactivation, pc_adjusted, mod, symname,

		       cudie, last_scope);

	  /* Found the "top-level" in which everything was inlined?  */

	  if (tag == DW_TAG_subprogram)

	    break;

	  last_scope = scope;

	}

    }

  free (scopes);

}

static void

print_frames (struct frames *frames, pid_t tid, int dwflerr, const char *what)

{

  if (frames->frames > 0)

    frames_shown = true;

  printf ("TID %lld:\n", (long long) tid);

  int frame_nr = 0;

  for (int nr = 0; nr < frames->frames && (maxframes == 0

					   || frame_nr < maxframes); nr++)

    {

      Dwarf_Addr pc = frames->frame[nr].pc;

      bool isactivation = frames->frame[nr].isactivation;

      Dwarf_Addr pc_adjusted = pc - (isactivation ? 0 : 1);

      /* Get PC->SYMNAME.  */

      Dwfl_Module *mod = dwfl_addrmodule (dwfl, pc_adjusted);

      const char *symname = NULL;

      Dwarf_Die die_mem;

      Dwarf_Die *die = NULL;

      Dwarf_Die *cudie = NULL;

      if (mod && ! show_quiet)

	{

	  if (show_debugname)

	    {

	      Dwarf_Addr bias = 0;

	      Dwarf_Die *scopes = NULL;

	      cudie = dwfl_module_addrdie (mod, pc_adjusted, &bias);

	      int nscopes = dwarf_getscopes (cudie, pc_adjusted - bias,

					     &scopes);

	      /* Find the first function-like DIE with a name in scope.  */

	      for (int i = 0; symname == NULL && i < nscopes; i++)

		{

		  Dwarf_Die *scope = &scopes[i];

		  int tag = dwarf_tag (scope);

		  if (tag == DW_TAG_subprogram

		      || tag == DW_TAG_inlined_subroutine

		      || tag == DW_TAG_entry_point)

		    symname = die_name (scope);

		  if (symname != NULL)

		    {

		      die_mem = *scope;

		      die = &die_mem;

		    }

		}

	      free (scopes);

	    }

	  if (symname == NULL)

	    symname = dwfl_module_addrname (mod, pc_adjusted);

	}

      if (show_inlines && die != NULL)

	print_inline_frames (&frame_nr, pc, isactivation, pc_adjusted, mod,

			     symname, cudie, die);

      else

	print_frame (frame_nr++, pc, isactivation, pc_adjusted, mod, symname,

		     NULL, NULL);

    }

  if (frames->frames > 0 && frame_nr == maxframes)

    error (0, 0, "tid %lld: shown max number of frames "

	   "(%d, use -n 0 for unlimited)", (long long) tid, maxframes);

  else if (dwflerr != 0)

    {

      if (frames->frames > 0)

	{

	  unsigned nr = frames->frames - 1;

	  Dwarf_Addr pc = frames->frame[nr].pc;

	  bool isactivation = frames->frame[nr].isactivation;

	  Dwarf_Addr pc_adjusted = pc - (isactivation ? 0 : 1);

	  Dwfl_Module *mod = dwfl_addrmodule (dwfl, pc_adjusted);

	  const char *mainfile = NULL;

	  const char *modname = dwfl_module_info (mod, NULL, NULL, NULL, NULL,

						  NULL, &mainfile, NULL);

	  if (modname == NULL || modname[0] == '\0')

	    {

	      if (mainfile != NULL)

		modname = mainfile;

	      else

		modname = "<unknown>";

	    }

	  error (0, 0, "%s tid %lld at 0x%" PRIx64 " in %s: %s", what,

		 (long long) tid, pc_adjusted, modname, dwfl_errmsg (dwflerr));

	}

      else

	error (0, 0, "%s tid %lld: %s", what, (long long) tid,

	       dwfl_errmsg (dwflerr));

    }

}

static int

thread_callback (Dwfl_Thread *thread, void *thread_arg)

{

  struct frames *frames = (struct frames *) thread_arg;

  pid_t tid = dwfl_thread_tid (thread);

  int err = 0;

  frames->frames = 0;

  switch (dwfl_thread_getframes (thread, frame_callback, thread_arg))

    {

    case DWARF_CB_OK:

    case DWARF_CB_ABORT:

      break;

    case -1:

      err = dwfl_errno ();

      break;

    default:

      abort ();

    }

  print_frames (frames, tid, err, "dwfl_thread_getframes");

  return DWARF_CB_OK;

}

static error_t

parse_opt (int key, char *arg __attribute__ ((unused)),

	   struct argp_state *state)

{

  switch (key)

    {

    case 'p':

      pid = atoi (arg);

      if (pid == 0)

	argp_error (state, N_("-p PID should be a positive process id."));

      break;

    case OPT_COREFILE:

      core_fd = open (arg, O_RDONLY);

      if (core_fd < 0)

	error (EXIT_BAD, errno, N_("Cannot open core file '%s'"), arg);

      elf_version (EV_CURRENT);

      core = elf_begin (core_fd, ELF_C_READ_MMAP, NULL);

      if (core == NULL)

	error (EXIT_BAD, 0, "core '%s' elf_begin: %s", arg, elf_errmsg(-1));

      break;

    case 'e':

      exec = arg;

      break;

    case OPT_DEBUGINFO:

      debuginfo_path = arg;

      break;

    case 'm':

      show_module = true;

      break;

    case 's':

      show_source = true;

      break;

    case 'a':

      show_activation = true;

      break;

    case 'd':

      show_debugname = true;

      break;

    case 'i':

      show_inlines = show_debugname = true;

      break;

    case 'v':

      show_activation = show_source = show_module = show_debugname = true;

      show_inlines = true;

      break;

    case 'b':

      show_build_id = true;

      break;

    case 'q':

      show_quiet = true;

      break;

    case 'r':

      show_raw = true;

      break;

    case '1':

      show_one_tid = true;

      break;

    case 'n':

      maxframes = atoi (arg);

      if (maxframes < 0)

	{

	  argp_error (state, N_("-n MAXFRAMES should be 0 or higher."));

	  return EINVAL;

	}

      break;

    case 'l':

      show_modules = true;

      break;

    case ARGP_KEY_END:

      if (core == NULL && exec != NULL)

	argp_error (state,

		    N_("-e EXEC needs a core given by --core."));

      if (pid == 0 && show_one_tid == true)

	argp_error (state,

		    N_("-1 needs a thread id given by -p."));

      if ((pid == 0 && core == NULL) || (pid != 0 && core != NULL))

	argp_error (state,

		    N_("One of -p PID or --core COREFILE should be given."));

      if (pid != 0)

	{

	  dwfl = dwfl_begin (&proc_callbacks);

	  if (dwfl == NULL)

	    error (EXIT_BAD, 0, "dwfl_begin: %s", dwfl_errmsg (-1));

	  int err = dwfl_linux_proc_report (dwfl, pid);

	  if (err < 0)

	    error (EXIT_BAD, 0, "dwfl_linux_proc_report pid %lld: %s",

		   (long long) pid, dwfl_errmsg (-1));

	  else if (err > 0)

	    error (EXIT_BAD, err, "dwfl_linux_proc_report pid %lld",

		   (long long) pid);

	}

      if (core != NULL)

	{

	  dwfl = dwfl_begin (&core_callbacks);

	  if (dwfl == NULL)

	    error (EXIT_BAD, 0, "dwfl_begin: %s", dwfl_errmsg (-1));

	  if (dwfl_core_file_report (dwfl, core, exec) < 0)

	    error (EXIT_BAD, 0, "dwfl_core_file_report: %s", dwfl_errmsg (-1));

	}

      if (dwfl_report_end (dwfl, NULL, NULL) != 0)

	error (EXIT_BAD, 0, "dwfl_report_end: %s", dwfl_errmsg (-1));

      if (pid != 0)

	{

	  int err = dwfl_linux_proc_attach (dwfl, pid, false);

	  if (err < 0)

	    error (EXIT_BAD, 0, "dwfl_linux_proc_attach pid %lld: %s",

		   (long long) pid, dwfl_errmsg (-1));

	  else if (err > 0)

	    error (EXIT_BAD, err, "dwfl_linux_proc_attach pid %lld",

		   (long long) pid);

	}

      if (core != NULL)

	{

	  if (dwfl_core_file_attach (dwfl, core) < 0)

	    error (EXIT_BAD, 0, "dwfl_core_file_attach: %s", dwfl_errmsg (-1));

	}

      /* Makes sure we are properly attached.  */

      if (dwfl_pid (dwfl) < 0)

	error (EXIT_BAD, 0, "dwfl_pid: %s\n", dwfl_errmsg (-1));

      break;

    default:

      return ARGP_ERR_UNKNOWN;

    }

  return 0;

}

int

main (int argc, char **argv)

{

  /* We use no threads here which can interfere with handling a stream.  */

  __fsetlocking (stdin, FSETLOCKING_BYCALLER);

  __fsetlocking (stdout, FSETLOCKING_BYCALLER);

  __fsetlocking (stderr, FSETLOCKING_BYCALLER);

  /* Set locale.  */

  (void) setlocale (LC_ALL, "");

  const struct argp_option options[] =

    {

      { NULL, 0, NULL, 0, N_("Input selection options:"), 0 },

      { "pid", 'p', "PID", 0,

	N_("Show stack of process PID"), 0 },

      { "core", OPT_COREFILE, "COREFILE", 0,

	N_("Show stack found in COREFILE"), 0 },

      {  "executable", 'e', "EXEC", 0, N_("(optional) EXECUTABLE that produced COREFILE"), 0 },

      { "debuginfo-path", OPT_DEBUGINFO, "PATH", 0,

	N_("Search path for separate debuginfo files"), 0 },

      { NULL, 0, NULL, 0, N_("Output selection options:"), 0 },

      { "activation",  'a', NULL, 0,

	N_("Additionally show frame activation"), 0 },

      { "debugname",  'd', NULL, 0,

	N_("Additionally try to lookup DWARF debuginfo name for frame address"),

	0 },

      { "inlines",  'i', NULL, 0,

	N_("Additionally show inlined function frames using DWARF debuginfo if available (implies -d)"), 0 },

      { "module",  'm', NULL, 0,

	N_("Additionally show module file information"), 0 },

      { "source",  's', NULL, 0,

	N_("Additionally show source file information"), 0 },

      { "verbose", 'v', NULL, 0,

	N_("Show all additional information (activation, debugname, inlines, module and source)"), 0 },

      { "quiet", 'q', NULL, 0,

	N_("Do not resolve address to function symbol name"), 0 },

      { "raw", 'r', NULL, 0,

	N_("Show raw function symbol names, do not try to demangle names"), 0 },

      { "build-id",  'b', NULL, 0,

	N_("Show module build-id, load address and pc offset"), 0 },

      { NULL, '1', NULL, 0,

	N_("Show the backtrace of only one thread"), 0 },

      { NULL, 'n', "MAXFRAMES", 0,

	N_("Show at most MAXFRAMES per thread (default 256, use 0 for unlimited)"), 0 },

      { "list-modules", 'l', NULL, 0,

	N_("Show module memory map with build-id, elf and debug files detected"), 0 },

      { NULL, 0, NULL, 0, NULL, 0 }

    };

  const struct argp argp =

    {

      .options = options,

      .parser = parse_opt,

      .doc = N_("Print a stack for each thread in a process or core file.\n\

\n\

Program exits with return code 0 if all frames were shown without \

any errors.  If some frames were shown, but there were some non-fatal \

errors, possibly causing an incomplete backtrace, the program exits \

with return code 1.  If no frames could be shown, or a fatal error \

occured the program exits with return code 2.  If the program was \

invoked with bad or missing arguments it will exit with return code 64.")

    };

  argp_parse (&argp, argc, argv, 0, NULL, NULL);

  if (show_modules)

    {

      printf ("PID %lld - %s module memory map\n", (long long) dwfl_pid (dwfl),

	      pid != 0 ? "process" : "core");

      if (dwfl_getmodules (dwfl, module_callback, NULL, 0) != 0)

	error (EXIT_BAD, 0, "dwfl_getmodules: %s", dwfl_errmsg (-1));

    }

  struct frames frames;

  /* When maxframes is zero, then 2048 is just the initial allocation

     that will be increased using realloc in framecallback ().  */

  frames.allocated = maxframes == 0 ? 2048 : maxframes;

  frames.frames = 0;

  frames.frame = malloc (sizeof (struct frame) * frames.allocated);

  if (frames.frame == NULL)

    error (EXIT_BAD, errno, "malloc frames.frame");

  if (show_one_tid)

    {

      int err = 0;

      switch (dwfl_getthread_frames (dwfl, pid, frame_callback, &frames))

	{

	case DWARF_CB_OK:

	case DWARF_CB_ABORT:

	  break;

	case -1:

	  err = dwfl_errno ();

	  break;

	default:

	  abort ();

	}

      print_frames (&frames, pid, err, "dwfl_getthread_frames");

    }

  else

    {

      printf ("PID %lld - %s\n", (long long) dwfl_pid (dwfl),

	      pid != 0 ? "process" : "core");

      switch (dwfl_getthreads (dwfl, thread_callback, &frames))

	{

	case DWARF_CB_OK:

	case DWARF_CB_ABORT:

	  break;

	case -1:

	  error (0, 0, "dwfl_getthreads: %s", dwfl_errmsg (-1));

	  break;

	default:

	  abort ();

	}

    }

  free (frames.frame);

  dwfl_end (dwfl);

  if (core != NULL)

    elf_end (core);

  if (core_fd != -1)

    close (core_fd);

#ifdef USE_DEMANGLE

  free (demangle_buffer);

#endif

  if (! frames_shown)

    error (EXIT_BAD, 0, N_("Couldn't show any frames."));

  return error_message_count != 0 ? EXIT_ERROR : EXIT_OK;

}