binutils-gdb/bfd/bfd.c

			   /* -*- C -*- */

/*** bfd -- binary file diddling routines by Gumby Wallace of Cygnus Support.
	    Every definition in this file should be exported and declared
	    in bfd.c.  If you don't want it to be user-visible, put it in
	    libbfd.c!
*/

/* Copyright (C) 1990, 1991 Free Software Foundation, Inc.

This file is part of BFD, the Binary File Diddler.

BFD 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 1, or (at your option)
any later version.

BFD 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 BFD; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* $Id$ */
#include "sysdep.h"
#include "bfd.h"
#include "libbfd.h"

short _bfd_host_big_endian = 0x0100;
	/* Accessing the above as (*(char*)&_bfd_host_big_endian), will
	 * return 1 if the host is big-endian, 0 otherwise.
	 * (See HOST_IS_BIG_ENDIAN_P in bfd.h.)
	 */




/** Error handling
    o - Most functions return nonzero on success (check doc for
	precise semantics); 0 or NULL on error.
    o - Internal errors are documented by the value of bfd_error.
	If that is system_call_error then check errno.
    o - The easiest way to report this to the user is to use bfd_perror.
*/

bfd_ec bfd_error = no_error;

char *bfd_errmsgs[] = {"No error",
		       "System call error",
		       "Invalid target",
		       "File in wrong format",
		       "Invalid operation",
		       "Memory exhausted",
		       "No symbols",
		       "No relocation info",
		       "No more archived files",
		       "Malformed archive",
		       "Symbol not found",
		       "File format not recognized",
		       "File format is ambiguous",
			   "Section has no contents",
		       "#<Invalid error code>"
		       };

#if !defined(ANSI_LIBRARIES)
char *
strerror (code)
     int code;
{
  extern int sys_nerr;
  extern char *sys_errlist[];

  return (((code < 0) || (code >= sys_nerr)) ? "(unknown error)" :
	  sys_errlist [code]);
}
#endif /* not ANSI_LIBRARIES */

char *
bfd_errmsg (error_tag)
     bfd_ec error_tag;
{
	extern int errno;

  if (error_tag == system_call_error)
    return strerror (errno);

  if ((((int)error_tag <(int) no_error) ||
       ((int)error_tag > (int)invalid_error_code)))
    error_tag = invalid_error_code;/* sanity check */

  return bfd_errmsgs [(int)error_tag];
}

void
bfd_perror (message)
     char *message;
{
  if (bfd_error == system_call_error)
    perror(message);		/* must be system error then... */
  else {
    if (message == NULL || *message == '\0')
      fprintf (stderr, "%s\n", bfd_errmsg (bfd_error));
    else
      fprintf (stderr, "%s: %s\n", message, bfd_errmsg (bfd_error));
  }
}

/* for error messages */
char *
bfd_format_string (format)
     bfd_format format;
{
  if (((int)format <(int) bfd_unknown) || ((int)format >=(int) bfd_type_end)) return "invalid";
  
  switch (format) {
  case bfd_object: return "object"; /* linker/assember/compiler output */
  case bfd_archive: return "archive"; /* object archive file */
  case bfd_core: return "core";	/* core dump */
  default: return "unknown";
  }
}

/** Target configurations */

extern bfd_target *target_vector[];

/* Returns a pointer to the transfer vector for the object target
   named target_name.  If target_name is NULL, chooses the one in the
   environment variable GNUTARGET; if that is null or not defined then
   the first entry in the target list is chosen.  Passing in the
   string "default" or setting the environment variable to "default"
   will cause the first entry in the target list to be returned. */

bfd_target *
bfd_find_target (target_name)
     char *target_name;
{
  bfd_target **target;
  extern char *getenv ();
  char *targname = (target_name ? target_name : getenv ("GNUTARGET"));

  /* This is safe; the vector cannot be null */
  if (targname == NULL || !strcmp (targname, "default"))
    return target_vector[0];

  for (target = &target_vector[0]; *target != NULL; target++) {
    if (!strcmp (targname, (*target)->name))
      return *target;
  }

  bfd_error = invalid_target;
  return NULL;
}

/* Returns a freshly-consed, NULL-terminated vector of the names of all the
   valid bfd targets.  Do not modify the names */

char **
bfd_target_list ()
{
  int vec_length= 0;
  bfd_target **target;
  char **name_list, **name_ptr;

  for (target = &target_vector[0]; *target != NULL; target++)
    vec_length++;

  name_ptr = name_list = (char **) zalloc ((vec_length + 1) * sizeof (char **));

  if (name_list == NULL) {
    bfd_error = no_memory;
    return NULL;
  }

  for (target = &target_vector[0]; *target != NULL; target++)
    *(name_ptr++) = (*target)->name;

  return name_list;
}

/** Init a bfd for read of the proper format.
 */

/* We should be able to find out if the target was defaulted or user-specified.
   If the user specified the target explicitly then we should do no search.
   I guess the best way to do this is to pass an extra argument which specifies
   the DWIM. */

/* I have chanegd this always to set the filepos to the origin before
   guessing.  -- Gumby, 14 Februar 1991*/

boolean
bfd_check_format (abfd, format)
     bfd *abfd;
     bfd_format format;
{
#if obsolete
  file_ptr filepos;
#endif
  bfd_target **target, *save_targ, *right_targ;
  int match_count;

  if (!bfd_read_p (abfd) ||
      ((int)(abfd->format) < (int)bfd_unknown) ||
      ((int)(abfd->format) >= (int)bfd_type_end)) {
    bfd_error = invalid_operation;
    return false;
  }

  if (abfd->format != bfd_unknown) return (abfd->format == format) ? true:false;

  /* presume the answer is yes */
  abfd->format = format;

#if obsolete
  filepos = bfd_tell (abfd);
#endif
  bfd_seek (abfd, (file_ptr)0, SEEK_SET);	/* instead, rewind! */


  right_targ = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
  if (right_targ) {
    abfd->xvec = right_targ;		/* Set the target as returned */
    return true;			/* File position has moved, BTW */
  }

  /* This isn't a <format> file in the specified or defaulted target type.
     See if we recognize it for any other target type.  (We check them
     all to make sure it's uniquely recognized.)  */

  save_targ = abfd->xvec;
  match_count = 0;
  right_targ = 0;

  for (target = target_vector; *target != NULL; target++) {
    bfd_target *temp;

    abfd->xvec = *target;	/* Change BFD's target temporarily */
#if obsolete
    bfd_seek (abfd, filepos, SEEK_SET);	/* Restore original file position */
#endif
    bfd_seek (abfd, (file_ptr)0, SEEK_SET);
    temp = BFD_SEND_FMT (abfd, _bfd_check_format, (abfd));
    if (temp) {				/* This format checks out as ok! */
      right_targ = temp;
      match_count++;
    }
  }

  if (match_count == 1) {
    abfd->xvec = right_targ;		/* Change BFD's target permanently */
    return true;			/* File position has moved, BTW */
  }

  abfd->xvec = save_targ;		/* Restore original target type */
  abfd->format = bfd_unknown;		/* Restore original format */
  bfd_error = ((match_count == 0) ? file_not_recognized :
	       file_ambiguously_recognized);
#if  obsolete
  bfd_seek (abfd, filepos, SEEK_SET);	/* Restore original file position */
#endif
  return false;
}

boolean
bfd_set_format (abfd, format)
     bfd *abfd;
     bfd_format format;
{
  file_ptr filepos;

  if (bfd_read_p (abfd) ||
      ((int)abfd->format < (int)bfd_unknown) ||
      ((int)abfd->format >= (int)bfd_type_end)) {
    bfd_error = invalid_operation;
    return false;
  }

  if (abfd->format != bfd_unknown) return (abfd->format == format) ? true:false;

  /* presume the answer is yes */
  abfd->format = format;

  filepos = bfd_tell (abfd);

  if (!BFD_SEND_FMT (abfd, _bfd_set_format, (abfd))) {
    abfd->format = bfd_unknown;
    bfd_seek (abfd, filepos, SEEK_SET);
    return false;
  }

  return true;
}

/* Hack object and core file sections */

sec_ptr
bfd_get_section_by_name (abfd, name)
     bfd *abfd;
     char *name;
{
  asection *sect;
  
  for (sect = abfd->sections; sect != NULL; sect = sect->next)
    if (!strcmp (sect->name, name)) return sect;
  return NULL;
}

/* If you try to create a section with a name which is already in use,
   returns the old section by that name instead. */
sec_ptr
bfd_make_section (abfd, name)
     bfd *abfd;
     char *name;
{
  asection *newsect;  
  asection **  prev = &abfd->sections;
  asection * sect = abfd->sections;
  
  if (abfd->output_has_begun) {
    bfd_error = invalid_operation;
    return NULL;
  }

  while (sect) {
    if (!strcmp(sect->name, name)) return sect;
    prev = &sect->next;
    sect = sect->next;
  }

  newsect = (asection *) zalloc (sizeof (asection));
  if (newsect == NULL) {
    bfd_error = no_memory;
    return NULL;
  }

  newsect->name = name;
  newsect->index = abfd->section_count++;
  newsect->flags = SEC_NO_FLAGS;

#if ignore	/* the compiler doesn't know that zalloc clears the storage */
  newsect->userdata = 0;
  newsect->next = (asection *)NULL;
  newsect->relocation = (arelent *)NULL;
  newsect->reloc_count = 0;
  newsect->line_filepos =0;
#endif
  if (BFD_SEND (abfd, _new_section_hook, (abfd, newsect)) != true) {
    free (newsect);
    return NULL;
  }

  *prev = newsect;
  return newsect;
}

/* Call operation on each section.  Operation gets three args: the bfd,
   the section, and a void * pointer (whatever the user supplied). */

/* This is attractive except that without lexical closures its use is hard
   to make reentrant. */
/*VARARGS2*/
void
bfd_map_over_sections (abfd, operation, user_storage)
     bfd *abfd;
     void (*operation)();
     void *user_storage;
{
  asection *sect;
  int i = 0;
  
  for (sect = abfd->sections; sect != NULL; i++, sect = sect->next)
    (*operation) (abfd, sect, user_storage);

  if (i != abfd->section_count)		/* Debugging */
    abort();
}

boolean
bfd_set_section_flags (abfd, section, flags)
     bfd *abfd;
     sec_ptr section;
     flagword flags;
{
  if ((flags & bfd_applicable_section_flags (abfd)) != flags) {
    bfd_error = invalid_operation;
    return false;
  }

   section->flags = flags;
return true;
}


boolean
bfd_set_section_size (abfd, ptr, val)
     bfd *abfd;
     sec_ptr ptr;
     unsigned long val;
{
  /* Once you've started writing to any section you cannot create or change
     the size of any others. */

  if (abfd->output_has_begun) {
    bfd_error = invalid_operation;
    return false;
  }

  ptr->size = val;
  
  return true;
}

boolean
bfd_set_section_contents (abfd, section, location, offset, count)
     bfd *abfd;
     sec_ptr section;
void *location;
     file_ptr offset;
     int count;
{
	if (!(bfd_get_section_flags(abfd, section) &
	      SEC_HAS_CONTENTS)) {
		bfd_error = no_contents;
		return(false);
	} /* if section has no contents */

  if (BFD_SEND (abfd, _bfd_set_section_contents,
	    (abfd, section, location, offset, count))) {
    abfd->output_has_begun = true;
    return true;
  }

  return false;
}

boolean
bfd_get_section_contents (abfd, section, location, offset, count)
     bfd *abfd;
     sec_ptr section;
     void *location;
     file_ptr offset;
     int count;
{
  if (section->flags & SEC_CONSTRUCTOR) {
    memset(location, 0, count);
    return true;
  }
  else {
    return  (BFD_SEND (abfd, _bfd_get_section_contents,
		       (abfd, section, location, offset, count)));
  }
}


/** Some core file info commands */

/* Returns a read-only string explaining what program was running when
   it failed. */

char *
bfd_core_file_failing_command (abfd)
     bfd *abfd;
{
  if (abfd->format != bfd_core) {
    bfd_error = invalid_operation;
    return NULL;
  }
  return BFD_SEND (abfd, _core_file_failing_command, (abfd));
}

int
bfd_core_file_failing_signal (abfd)
     bfd *abfd;
{
  if (abfd->format != bfd_core) {
    bfd_error = invalid_operation;
    return NULL;
  }
  return BFD_SEND (abfd, _core_file_failing_signal, (abfd));
}

boolean
core_file_matches_executable_p (core_bfd, exec_bfd)
     bfd *core_bfd, *exec_bfd;
{
  if ((core_bfd->format != bfd_core) || (exec_bfd->format != bfd_object)) {
    bfd_error = wrong_format;
    return false;
  }

  return BFD_SEND (core_bfd, _core_file_matches_executable_p, (core_bfd, exec_bfd));
}

/** Symbols */

boolean
bfd_set_symtab (abfd, location, symcount)
     bfd *abfd;
     asymbol **location;
     unsigned int symcount;
{
  if ((abfd->format != bfd_object) || (bfd_read_p (abfd))) {
    bfd_error = invalid_operation;
    return false;
  }

  bfd_get_outsymbols (abfd) = location;
  bfd_get_symcount (abfd) = symcount;
  return true;
}

/* returns the number of octets of storage required */
unsigned int
get_reloc_upper_bound (abfd, asect)
     bfd *abfd;
     sec_ptr asect;
{
  if (abfd->format != bfd_object) {
    bfd_error = invalid_operation;
    return 0;
  }

  return BFD_SEND (abfd, _get_reloc_upper_bound, (abfd, asect));
}

unsigned int
bfd_canonicalize_reloc (abfd, asect, location, symbols)
     bfd *abfd;
     sec_ptr asect;
     arelent **location;
     asymbol **symbols;
{
  if (abfd->format != bfd_object) {
    bfd_error = invalid_operation;
    return 0;
  }

  return BFD_SEND (abfd, _bfd_canonicalize_reloc, (abfd, asect, location, symbols));
}

void
bfd_print_symbol_vandf(file, symbol)
void *file;
asymbol *symbol;
{
  flagword type = symbol->flags;
  if (symbol->section != (asection *)NULL)
    {
      fprintf(file,"%08lx ", symbol->value+symbol->section->vma);
    }
  else 
    {
      fprintf(file,"%08lx ", symbol->value);
    }
  fprintf(file,"%c%c%c%c%c%c%c",
	  (type & BSF_LOCAL)  ? 'l':' ',
	  (type & BSF_GLOBAL) ? 'g' : ' ',
	  (type & BSF_IMPORT) ? 'i' : ' ',
	  (type & BSF_EXPORT) ? 'e' : ' ',
	  (type & BSF_UNDEFINED) ? 'u' : ' ',
	  (type & BSF_FORT_COMM) ? 'c' : ' ',
	  (type & BSF_DEBUGGING) ? 'd' :' ');

}


boolean
bfd_set_file_flags (abfd, flags)
     bfd *abfd;
     flagword flags;
{
  if (abfd->format != bfd_object) {
    bfd_error = wrong_format;
    return false;
  }

  if (bfd_read_p (abfd)) {
    bfd_error = invalid_operation;
    return false;
  }

  if ((flags & bfd_applicable_file_flags (abfd)) != flags) {
    bfd_error = invalid_operation;
    return false;
  }

  bfd_get_file_flags (abfd) = flags;
return true;
}


void
bfd_set_reloc (ignore_abfd, asect, location, count)
     bfd *ignore_abfd;
     sec_ptr asect;
     arelent **location;
     unsigned int count;
{
  asect->orelocation  = location;
  asect->reloc_count = count;
}
/*
If an output_bfd is supplied to this function the generated image
will be relocatable, the relocations are copied to the output file
after they have been changed to reflect the new state of the world.
There are two ways of reflecting the results of partial linkage in an
output file; by modifying the output data in place, and by modifying
the relocation record. Some native formats (eg basic a.out and basic
coff) have no way of specifying an addend in the relocation type, so
the addend has to go in the output data.  This is no big deal since in
these formats the output data slot will always be big enough for the
addend. Complex reloc types with addends were invented to solve just
this problem.
*/

bfd_reloc_status_enum_type
bfd_perform_relocation(abfd,
		       reloc_entry,
		       data,
		       input_section,
		       output_bfd)
bfd *abfd;
arelent *reloc_entry;
void  *data;
asection *input_section;
bfd *output_bfd;
{
  bfd_vma relocation;
  bfd_reloc_status_enum_type flag = bfd_reloc_ok;
  bfd_vma relocation_before;
  bfd_vma mask;
  bfd_vma target_mask;
  bfd_vma addr = reloc_entry->address ;
  bfd_vma output_base = 0;
  struct rint_struct *howto = reloc_entry->howto;
  asection *reloc_target_output_section;
  asection *reloc_target_input_section;
  asymbol *symbol;

  if (reloc_entry->sym_ptr_ptr) {
    symbol = *( reloc_entry->sym_ptr_ptr);
    if ((symbol->flags & BSF_UNDEFINED) && output_bfd == (bfd *)NULL) {
      flag = bfd_reloc_undefined;
    }
  }
  else {
    symbol = (asymbol*)NULL;
  }

  if (howto->special_function) {
    bfd_reloc_status_enum_type cont;
    cont = howto->special_function(abfd,
				   reloc_entry,
				   symbol,
				   data,
				   input_section);
    if (cont != bfd_reloc_continue) return cont;
  }

  /* 
     Work out which section the relocation is targetted at and the
     initial relocation command value.
     */


  if (symbol != (asymbol *)NULL){
    if (symbol->flags & BSF_FORT_COMM) {
      relocation = 0;
    }
    else {
      relocation = symbol->value;
    }
    if (symbol->section != (asection *)NULL)
      {
	reloc_target_input_section = symbol->section;
      }
    else {
      reloc_target_input_section = (asection *)NULL;
    }
  }
  else if (reloc_entry->section != (asection *)NULL)
    {
      relocation = 0;
      reloc_target_input_section = reloc_entry->section;
    }
  else {
    relocation = 0;
    reloc_target_input_section = (asection *)NULL;
  }


  if (reloc_target_input_section != (asection *)NULL) {

    reloc_target_output_section =
      reloc_target_input_section->output_section;

    if (output_bfd && howto->partial_inplace==false) {
      output_base = 0;
    }
    else {
      output_base = reloc_target_output_section->vma;

    }

    relocation += output_base +   reloc_target_input_section->output_offset;
  }

  relocation += reloc_entry->addend ;


  if(reloc_entry->address > (bfd_vma)(input_section->size)) 
    {
      return bfd_reloc_outofrange;
    }
	  

  if (howto->pc_relative == true)
    {
      /*
	 Anything which started out as pc relative should end up that
	 way too 
	 */

      relocation -= 
	output_base +   input_section->output_offset;

    }

  if (output_bfd!= (bfd *)NULL &&   howto->partial_inplace == false)  {
    /*
       This is a partial relocation, and we want to apply the relocation
       to the reloc entry rather than the raw data. Modify the reloc
       inplace to reflect what we now know.
       */
    reloc_entry->addend = relocation  ;
    reloc_entry->section = reloc_target_input_section;
    if (reloc_target_input_section != (asection *)NULL) {
      /* If we know the output section we can forget the symbol */
      reloc_entry->sym_ptr_ptr = (asymbol**)NULL;
    }
    reloc_entry->address += 
      input_section->output_offset;
  }
  else {
    reloc_entry->addend = 0;


    /* 
       Either we are relocating all the way, or we don't want to apply
       the relocation to the reloc entry (probably because there isn't
       any room in the output format to describe addends to relocs)
       */
    relocation >>= howto->rightshift;
    if (howto->bitsize == 32) {
      mask = ~0;
    }
    else {
      mask = (1L << howto->bitsize) - 1 ;
      mask |= mask - 1;		/* FIXME, what is this?  */
    }

    relocation &= mask;

    /* Shift everything up to where it's going to be used */
   
    relocation <<= howto->bitpos;
    mask <<= howto->bitpos;
    target_mask = ~mask;

    /* Wait for the day when all have the mask in them */

    BFD_ASSERT(howto->mask == mask);



    relocation_before = relocation;


    switch (howto->size)
      {
      case 0:
	{
	  char x = bfd_getchar(abfd, (char *)data + addr);
	  relocation +=  x & mask;
	  bfd_putchar(abfd,
		      ( x & target_mask) | ( relocation & mask),
		      (unsigned char *) data + addr);
	}
	break;

      case 1:
 	{ 
	  short x = bfd_getshort(abfd, (bfd_byte *)data + addr);
	  relocation += x & mask;
	  bfd_putshort(abfd, ( x & target_mask) | (relocation & mask),
		       (unsigned char *)data + addr);
	}
	break;
      case 2:
	{
	  long  x = bfd_getlong(abfd, (bfd_byte *) data + addr);
	  relocation +=  x & mask;
	  bfd_putlong(abfd, ( x & target_mask) | (relocation & mask),
		      (bfd_byte *)data + addr);
	}	   
	break;
      case 3:
	/* Do nothing */
	break;
      default:
	return bfd_reloc_other;
      }

    /* See if important parts of the relocation were chopped to make
       it fit into the relocation field. (ie are there any significant
       bits left over after the masking ? */
    if ((relocation_before & target_mask) != 0 &&
	howto->complain_on_overflow == true) 
      {
	/* Its ok if the bit which fell off is */
	return bfd_reloc_overflow;
      }
  }

  return flag;
}

void
bfd_assert(file, line)
char *file;
int line;
{
  printf("bfd assertion fail %s:%d\n",file,line);
}


boolean
bfd_set_start_address(abfd, vma)
bfd *abfd;
bfd_vma vma;
{
  abfd->start_address = vma;
  return true;
}


bfd_vma bfd_log2(x)
bfd_vma x;
{
  bfd_vma  result = 0;
  while ( (bfd_vma)(1<< result) < x)
    result++;
  return result;
}

/* bfd_get_mtime:  Return cached file modification time (e.g. as read
   from archive header for archive members, or from file system if we have
   been called before); else determine modify time, cache it, and
   return it.  */

long
bfd_get_mtime (abfd)
     bfd *abfd;
{
  FILE *fp;
  struct stat buf;

  if (abfd->mtime_set)
    return abfd->mtime;

  fp = bfd_cache_lookup (abfd);
  if (0 != fstat (fileno (fp), &buf))
    return 0;

  abfd->mtime_set = true;
  abfd->mtime = buf.st_mtime;
  return abfd->mtime;
}