src/objdump.c

/* Print information from ELF file in human-readable form.
   Copyright (C) 2005, 2006, 2007, 2009 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2005.

   Red Hat elfutils 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; version 2 of the License.

   Red Hat 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 Red Hat elfutils; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.

   Red Hat elfutils is an included package of the Open Invention Network.
   An included package of the Open Invention Network is a package for which
   Open Invention Network licensees cross-license their patents.  No patent
   license is granted, either expressly or impliedly, by designation as an
   included package.  Should you wish to participate in the Open Invention
   Network licensing program, please visit www.openinventionnetwork.com
   <http://www.openinventionnetwork.com>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <argp.h>
#include <error.h>
#include <fcntl.h>
#include <inttypes.h>
#include <libintl.h>
#include <locale.h>
#include <mcheck.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/param.h>

#include <system.h>
#include "../libebl/libeblP.h"


/* Name and version of program.  */
static void print_version (FILE *stream, struct argp_state *state);
ARGP_PROGRAM_VERSION_HOOK_DEF = print_version;

/* Bug report address.  */
ARGP_PROGRAM_BUG_ADDRESS_DEF = PACKAGE_BUGREPORT;


/* Definitions of arguments for argp functions.  */
static const struct argp_option options[] =
{
  { NULL, 0, NULL, 0, N_("Mode selection:"), 0 },
  { "reloc", 'r', NULL, 0, N_("Display relocation information."), 0 },
  { "full-contents", 's', NULL, 0,
    N_("Display the full contents of all sections requested"), 0 },
  { "disassemble", 'd', NULL, 0,
    N_("Display assembler code of executable sections"), 0 },

  { NULL, 0, NULL, 0, N_("Output option selection:"), 0 },
  { "section", 'j', "NAME", 0,
    N_("Only display information for section NAME."), 0 },

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

/* Short description of program.  */
static const char doc[] = N_("\
Show information from FILEs (a.out by default).");

/* Strings for arguments in help texts.  */
static const char args_doc[] = N_("[FILE...]");

/* Prototype for option handler.  */
static error_t parse_opt (int key, char *arg, struct argp_state *state);

/* Data structure to communicate with argp functions.  */
static struct argp argp =
{
  options, parse_opt, args_doc, doc, NULL, NULL, NULL
};


/* Print symbols in file named FNAME.  */
static int process_file (const char *fname, bool more_than_one);

/* Handle content of archive.  */
static int handle_ar (int fd, Elf *elf, const char *prefix, const char *fname,
		      const char *suffix);

/* Handle ELF file.  */
static int handle_elf (Elf *elf, const char *prefix, const char *fname,
		       const char *suffix);


#define INTERNAL_ERROR(fname) \
  error (EXIT_FAILURE, 0, gettext ("%s: INTERNAL ERROR %d (%s-%s): %s"),      \
	 fname, __LINE__, PACKAGE_VERSION, __DATE__, elf_errmsg (-1))


/* List of sections which should be used.  */
static struct section_list
{
  bool is_name;
  union
  {
    const char *name;
    uint32_t scnndx;
  };
  struct section_list *next;
} *section_list;


/* If true print archive index.  */
static bool print_relocs;

/* If true print full contents of requested sections.  */
static bool print_full_content;

/* If true print disassembled output..  */
static bool print_disasm;

int
main (int argc, char *argv[])
{
  /* Make memory leak detection possible.  */
  mtrace ();

  /* We use no threads here which can interfere with handling a stream.  */
  (void) __fsetlocking (stdin, FSETLOCKING_BYCALLER);
  (void) __fsetlocking (stdout, FSETLOCKING_BYCALLER);
  (void) __fsetlocking (stderr, FSETLOCKING_BYCALLER);

  /* Set locale.  */
  (void) setlocale (LC_ALL, "");

  /* Make sure the message catalog can be found.  */
  (void) bindtextdomain (PACKAGE_TARNAME, LOCALEDIR);

  /* Initialize the message catalog.  */
  (void) textdomain (PACKAGE_TARNAME);

  /* Parse and process arguments.  */
  int remaining;
  (void) argp_parse (&argp, argc, argv, 0, &remaining, NULL);

  /* Tell the library which version we are expecting.  */
  (void) elf_version (EV_CURRENT);

  int result = 0;
  if (remaining == argc)
    /* The user didn't specify a name so we use a.out.  */
    result = process_file ("a.out", false);
  else
    {
      /* Process all the remaining files.  */
      const bool more_than_one = remaining + 1 < argc;

      do
	result |= process_file (argv[remaining], more_than_one);
      while (++remaining < argc);
    }

  return result;
}


/* Print the version information.  */
static void
print_version (FILE *stream, struct argp_state *state __attribute__ ((unused)))
{
  fprintf (stream, "objdump (%s) %s\n", PACKAGE_NAME, PACKAGE_VERSION);
  fprintf (stream, gettext ("\
Copyright (C) %s Red Hat, Inc.\n\
This is free software; see the source for copying conditions.  There is NO\n\
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
"), "20089");
  fprintf (stream, gettext ("Written by %s.\n"), "Ulrich Drepper");
}


/* Handle program arguments.  */
static error_t
parse_opt (int key, char *arg,
	   struct argp_state *state __attribute__ ((unused)))
{
  /* True if any of the control options is set.  */
  static bool any_control_option;

  switch (key)
    {
    case 'j':
      {
	struct section_list *newp = xmalloc (sizeof (*newp));
	char *endp;
	newp->scnndx = strtoul (arg, &endp, 0);
	if (*endp == 0)
	  newp->is_name = false;
	else
	  {
	    newp->name = arg;
	    newp->is_name = true;
	  }
	newp->next = section_list;
	section_list = newp;
      }
      any_control_option = true;
      break;

    case 'd':
      print_disasm = true;
      any_control_option = true;
      break;

    case 'r':
      print_relocs = true;
      any_control_option = true;
      break;

    case 's':
      print_full_content = true;
      any_control_option = true;
      break;

    case ARGP_KEY_FINI:
      if (! any_control_option)
	{
	  fputs (gettext ("No operation specified.\n"), stderr);
	  argp_help (&argp, stderr, ARGP_HELP_SEE,
		     program_invocation_short_name);
	  exit (EXIT_FAILURE);
	}

    default:
      return ARGP_ERR_UNKNOWN;
    }
  return 0;
}


/* Open the file and determine the type.  */
static int
process_file (const char *fname, bool more_than_one)
{
  /* Open the file.  */
  int fd = open (fname, O_RDONLY);
  if (fd == -1)
    {
      error (0, errno, gettext ("cannot open %s"), fname);
      return 1;
    }

  /* Now get the ELF descriptor.  */
  Elf *elf = elf_begin (fd, ELF_C_READ_MMAP, NULL);
  if (elf != NULL)
    {
      if (elf_kind (elf) == ELF_K_ELF)
	{
	  int result = handle_elf (elf, more_than_one ? "" : NULL,
				   fname, NULL);

	  if (elf_end (elf) != 0)
	    INTERNAL_ERROR (fname);

	  if (close (fd) != 0)
	    error (EXIT_FAILURE, errno, gettext ("while close `%s'"), fname);

	  return result;
	}
      else if (elf_kind (elf) == ELF_K_AR)
	{
	  int result = handle_ar (fd, elf, NULL, fname, NULL);

	  if (elf_end (elf) != 0)
	    INTERNAL_ERROR (fname);

	  if (close (fd) != 0)
	    error (EXIT_FAILURE, errno, gettext ("while close `%s'"), fname);

	  return result;
	}

      /* We cannot handle this type.  Close the descriptor anyway.  */
      if (elf_end (elf) != 0)
	INTERNAL_ERROR (fname);
    }

  error (0, 0, gettext ("%s: File format not recognized"), fname);

  return 1;
}


static int
handle_ar (int fd, Elf *elf, const char *prefix, const char *fname,
	   const char *suffix)
{
  size_t fname_len = strlen (fname) + 1;
  size_t prefix_len = prefix != NULL ? strlen (prefix) : 0;
  char new_prefix[prefix_len + fname_len + 2];
  size_t suffix_len = suffix != NULL ? strlen (suffix) : 0;
  char new_suffix[suffix_len + 2];
  Elf *subelf;
  Elf_Cmd cmd = ELF_C_READ_MMAP;
  int result = 0;

  char *cp = new_prefix;
  if (prefix != NULL)
    cp = stpcpy (cp, prefix);
  cp = stpcpy (cp, fname);
  stpcpy (cp, "[");

  cp = new_suffix;
  if (suffix != NULL)
    cp = stpcpy (cp, suffix);
  stpcpy (cp, "]");

  /* Process all the files contained in the archive.  */
  while ((subelf = elf_begin (fd, cmd, elf)) != NULL)
    {
      /* The the header for this element.  */
      Elf_Arhdr *arhdr = elf_getarhdr (subelf);

      /* Skip over the index entries.  */
      if (strcmp (arhdr->ar_name, "/") != 0
	  && strcmp (arhdr->ar_name, "//") != 0)
	{
	  if (elf_kind (subelf) == ELF_K_ELF)
	    result |= handle_elf (subelf, new_prefix, arhdr->ar_name,
				  new_suffix);
	  else if (elf_kind (subelf) == ELF_K_AR)
	    result |= handle_ar (fd, subelf, new_prefix, arhdr->ar_name,
				 new_suffix);
	  else
	    {
	      error (0, 0, gettext ("%s%s%s: file format not recognized"),
		     new_prefix, arhdr->ar_name, new_suffix);
	      result = 1;
	    }
	}

      /* Get next archive element.  */
      cmd = elf_next (subelf);
      if (elf_end (subelf) != 0)
	INTERNAL_ERROR (fname);
    }

  return result;
}


static void
show_relocs_x (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *symdata,
	       Elf_Data *xndxdata, size_t symstrndx, size_t shstrndx,
	       GElf_Addr r_offset, GElf_Xword r_info, GElf_Sxword r_addend)
{
  int elfclass = gelf_getclass (ebl->elf);
  char buf[128];

  printf ("%0*" PRIx64 " %-20s ",
	  elfclass == ELFCLASS32 ? 8 : 16, r_offset,
	  ebl_reloc_type_name (ebl, GELF_R_TYPE (r_info), buf, sizeof (buf)));

  Elf32_Word xndx;
  GElf_Sym symmem;
  GElf_Sym *sym = gelf_getsymshndx (symdata, xndxdata, GELF_R_SYM (r_info),
				    &symmem, &xndx);

  if (sym == NULL)
    printf ("<%s %ld>",
	    gettext ("INVALID SYMBOL"), (long int) GELF_R_SYM (r_info));
  else if (GELF_ST_TYPE (sym->st_info) != STT_SECTION)
    printf ("%s",
	    elf_strptr (ebl->elf, symstrndx, sym->st_name));
  else
    {
      GElf_Shdr destshdr_mem;
      GElf_Shdr *destshdr;
      destshdr = gelf_getshdr (elf_getscn (ebl->elf,
					   sym->st_shndx == SHN_XINDEX
					   ? xndx : sym->st_shndx),
			       &destshdr_mem);

      if (shdr == NULL)
	printf ("<%s %ld>",
		gettext ("INVALID SECTION"),
		(long int) (sym->st_shndx == SHN_XINDEX
			    ? xndx : sym->st_shndx));
      else
	printf ("%s",
		elf_strptr (ebl->elf, shstrndx, destshdr->sh_name));
    }

  if (r_addend != 0)
    {
      char sign = '+';
      if (r_addend < 0)
	{
	  sign = '-';
	  r_addend = -r_addend;
	}
      printf ("%c%#" PRIx64, sign, r_addend);
    }
  putchar ('\n');
}


static void
show_relocs_rel (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *data,
		 Elf_Data *symdata, Elf_Data *xndxdata, size_t symstrndx,
		 size_t shstrndx)
{
  int nentries = shdr->sh_size / shdr->sh_entsize;

  for (int cnt = 0; cnt < nentries; ++cnt)
    {
      GElf_Rel relmem;
      GElf_Rel *rel;

      rel = gelf_getrel (data, cnt, &relmem);
      if (rel != NULL)
	show_relocs_x (ebl, shdr, symdata, xndxdata, symstrndx, shstrndx,
		       rel->r_offset, rel->r_info, 0);
    }
}


static void
show_relocs_rela (Ebl *ebl, GElf_Shdr *shdr, Elf_Data *data,
		  Elf_Data *symdata, Elf_Data *xndxdata, size_t symstrndx,
		  size_t shstrndx)
{
  int nentries = shdr->sh_size / shdr->sh_entsize;

  for (int cnt = 0; cnt < nentries; ++cnt)
    {
      GElf_Rela relmem;
      GElf_Rela *rel;

      rel = gelf_getrela (data, cnt, &relmem);
      if (rel != NULL)
	show_relocs_x (ebl, shdr, symdata, xndxdata, symstrndx, shstrndx,
		       rel->r_offset, rel->r_info, rel->r_addend);
    }
}


static bool
section_match (Elf *elf, uint32_t scnndx, GElf_Shdr *shdr, size_t shstrndx)
{
  if (section_list == NULL)
    return true;

  struct section_list *runp = section_list;

  do
    {
      if (runp->is_name)
	{
	  if (strcmp (runp->name,
		      elf_strptr (elf, shstrndx, shdr->sh_name)) == 0)
	    return true;
	}
      else
	{
	  if (runp->scnndx == scnndx)
	    return true;
	}

      runp = runp->next;
    }
  while (runp != NULL);

  return false;
}


static int
show_relocs (Ebl *ebl, const char *fname, uint32_t shstrndx)
{
  int elfclass = gelf_getclass (ebl->elf);

  Elf_Scn *scn = NULL;
  while ((scn = elf_nextscn (ebl->elf, scn)) != NULL)
    {
      GElf_Shdr shdr_mem;
      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);

      if (shdr == NULL)
	INTERNAL_ERROR (fname);

      if (shdr->sh_type == SHT_REL || shdr->sh_type == SHT_RELA)
	{
 	  if  (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx))
	    continue;

	  GElf_Shdr destshdr_mem;
	  GElf_Shdr *destshdr = gelf_getshdr (elf_getscn (ebl->elf,
							  shdr->sh_info),
					      &destshdr_mem);

	  printf (gettext ("\nRELOCATION RECORDS FOR [%s]:\n"
			   "%-*s TYPE                 VALUE\n"),
		  elf_strptr (ebl->elf, shstrndx, destshdr->sh_name),
		  elfclass == ELFCLASS32 ? 8 : 16, gettext ("OFFSET"));

	  /* Get the data of the section.  */
	  Elf_Data *data = elf_getdata (scn, NULL);
	  if (data == NULL)
	    continue;

	  /* Get the symbol table information.  */
	  Elf_Scn *symscn = elf_getscn (ebl->elf, shdr->sh_link);
	  GElf_Shdr symshdr_mem;
	  GElf_Shdr *symshdr = gelf_getshdr (symscn, &symshdr_mem);
	  Elf_Data *symdata = elf_getdata (symscn, NULL);

	  /* Search for the optional extended section index table.  */
	  Elf_Data *xndxdata = NULL;
	  Elf_Scn *xndxscn = NULL;
	  while ((xndxscn = elf_nextscn (ebl->elf, xndxscn)) != NULL)
	    {
	      GElf_Shdr xndxshdr_mem;
	      GElf_Shdr *xndxshdr;

	      xndxshdr = gelf_getshdr (xndxscn, &xndxshdr_mem);
	      if (xndxshdr != NULL && xndxshdr->sh_type == SHT_SYMTAB_SHNDX
		  && xndxshdr->sh_link == elf_ndxscn (symscn))
		{
		  /* Found it.  */
		  xndxdata = elf_getdata (xndxscn, NULL);
		  break;
		}
	    }

	  if (shdr->sh_type == SHT_REL)
	    show_relocs_rel (ebl, shdr, data, symdata, xndxdata,
			     symshdr->sh_link, shstrndx);
	  else
	    show_relocs_rela (ebl, shdr, data, symdata, xndxdata,
			      symshdr->sh_link, shstrndx);

	  putchar ('\n');
	}
    }

  return 0;
}


static int
show_full_content (Ebl *ebl, const char *fname, uint32_t shstrndx)
{
  Elf_Scn *scn = NULL;
  while ((scn = elf_nextscn (ebl->elf, scn)) != NULL)
    {
      GElf_Shdr shdr_mem;
      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);

      if (shdr == NULL)
	INTERNAL_ERROR (fname);

      if (shdr->sh_type == SHT_PROGBITS && shdr->sh_size > 0)
	{
 	  if  (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx))
	    continue;

	  printf (gettext ("Contents of section %s:\n"),
		  elf_strptr (ebl->elf, shstrndx, shdr->sh_name));

	  /* Get the data of the section.  */
	  Elf_Data *data = elf_getdata (scn, NULL);
	  if (data == NULL)
	    continue;

	  unsigned char *cp = data->d_buf;
	  size_t cnt;
	  for (cnt = 0; cnt + 16 < data->d_size; cp += 16, cnt += 16)
	    {
	      printf (" %04zx ", cnt);

	      for (size_t inner = 0; inner < 16; inner += 4)
		printf ("%02hhx%02hhx%02hhx%02hhx ",
			cp[inner], cp[inner + 1], cp[inner + 2],
			cp[inner + 3]);
	      fputc_unlocked (' ', stdout);

	      for (size_t inner = 0; inner < 16; ++inner)
		fputc_unlocked (isascii (cp[inner]) && isprint (cp[inner])
				? cp[inner] : '.', stdout);
	      fputc_unlocked ('\n', stdout);
	    }

	  printf (" %04zx ", cnt);

	  size_t remaining = data->d_size - cnt;
	  size_t inner;
	  for (inner = 0; inner + 4 <= remaining; inner += 4)
	    printf ("%02hhx%02hhx%02hhx%02hhx ",
		    cp[inner], cp[inner + 1], cp[inner + 2], cp[inner + 3]);

	  for (; inner < remaining; ++inner)
	    printf ("%02hhx", cp[inner]);

	  for (inner = 2 * (16 - inner) + (16 - inner + 3) / 4 + 1; inner > 0;
	       --inner)
	    fputc_unlocked (' ', stdout);

	  for (inner = 0; inner < remaining; ++inner)
	    fputc_unlocked (isascii (cp[inner]) && isprint (cp[inner])
			    ? cp[inner] : '.', stdout);
	  fputc_unlocked ('\n', stdout);

	  fputc_unlocked ('\n', stdout);
	}
    }

  return 0;
}


struct disasm_info
{
  GElf_Addr addr;
  const uint8_t *cur;
  const uint8_t *last_end;
};


// XXX This is not the preferred output for all architectures.  Needs
// XXX customization, too.
static int
disasm_output (char *buf, size_t buflen, void *arg)
{
  struct disasm_info *info = (struct disasm_info *) arg;

  printf ("%8" PRIx64 ":   ", (uint64_t) info->addr);
  size_t cnt;
  for (cnt = 0; cnt < (size_t) MIN (info->cur - info->last_end, 8); ++cnt)
    printf (" %02" PRIx8, info->last_end[cnt]);
  printf ("%*s %.*s\n",
	  (int) (8 - cnt) * 3 + 1, "", (int) buflen, buf);

  info->addr += cnt;

  /* We limit the number of bytes printed before the mnemonic to 8.
     Print the rest on a separate, following line.  */
  if (info->cur - info->last_end > 8)
    {
      printf ("%8" PRIx64 ":   ", (uint64_t) info->addr);
      for (; cnt < (size_t) (info->cur - info->last_end); ++cnt)
	printf (" %02" PRIx8, info->last_end[cnt]);
      putchar_unlocked ('\n');
      info->addr += info->cur - info->last_end - 8;
    }

  info->last_end = info->cur;

  return 0;
}


static int
show_disasm (Ebl *ebl, const char *fname, uint32_t shstrndx)
{
  DisasmCtx_t *ctx = disasm_begin (ebl, ebl->elf, NULL /* XXX TODO */);
  if (ctx == NULL)
    error (EXIT_FAILURE, 0, gettext ("cannot disassemble"));

  Elf_Scn *scn = NULL;
  while ((scn = elf_nextscn (ebl->elf, scn)) != NULL)
    {
      GElf_Shdr shdr_mem;
      GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);

      if (shdr == NULL)
	INTERNAL_ERROR (fname);

      if (shdr->sh_type == SHT_PROGBITS && shdr->sh_size > 0
	  && (shdr->sh_flags & SHF_EXECINSTR) != 0)
	{
 	  if  (! section_match (ebl->elf, elf_ndxscn (scn), shdr, shstrndx))
	    continue;

	  Elf_Data *data = elf_getdata (scn, NULL);
	  if (data == NULL)
	    continue;

	  printf ("Disassembly of section %s:\n\n",
		  elf_strptr (ebl->elf, shstrndx, shdr->sh_name));

	  struct disasm_info info;
	  info.addr = shdr->sh_addr;
	  info.last_end = info.cur = data->d_buf;

	  disasm_cb (ctx, &info.cur, info.cur + data->d_size, info.addr,
		     "%7m %.1o,%.2o,%.3o%34a %l", disasm_output, &info,
		     NULL /* XXX */);
	}
    }

  (void) disasm_end (ctx);

  return 0;
}


static int
handle_elf (Elf *elf, const char *prefix, const char *fname,
	    const char *suffix)
{

  /* Get the backend for this object file type.  */
  Ebl *ebl = ebl_openbackend (elf);

  printf ("%s: elf%d-%s\n\n",
	  fname, gelf_getclass (elf) == ELFCLASS32 ? 32 : 64,
	  ebl_backend_name (ebl));

  /* Create the full name of the file.  */
  size_t prefix_len = prefix == NULL ? 0 : strlen (prefix);
  size_t suffix_len = suffix == NULL ? 0 : strlen (suffix);
  size_t fname_len = strlen (fname) + 1;
  char fullname[prefix_len + 1 + fname_len + suffix_len];
  char *cp = fullname;
  if (prefix != NULL)
    cp = mempcpy (cp, prefix, prefix_len);
  cp = mempcpy (cp, fname, fname_len);
  if (suffix != NULL)
    memcpy (cp - 1, suffix, suffix_len + 1);

  /* Get the section header string table index.  */
  size_t shstrndx;
  if (elf_getshdrstrndx (ebl->elf, &shstrndx) < 0)
    error (EXIT_FAILURE, 0,
	   gettext ("cannot get section header string table index"));

  int result = 0;
  if (print_disasm)
    result = show_disasm (ebl, fullname, shstrndx);
  if (print_relocs && !print_disasm)
    result = show_relocs (ebl, fullname, shstrndx);
  if (print_full_content)
    result = show_full_content (ebl, fullname, shstrndx);

  /* Close the ELF backend library descriptor.  */
  ebl_closebackend (ebl);

  return result;
}


#include "debugpred.h"