libdwarf/dwarf_srcfiles.c

/* Return source files of compilation unit.
   Copyright (C) 2000, 2002 Red Hat, Inc.
   This file is part of Red Hat elfutils.
   Written by Ulrich Drepper <drepper@redhat.com>, 2000.

   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 <dwarf.h>
#include <stdlib.h>
#include <string.h>

#include <libdwarfP.h>


struct dirlist
{
  char *dir;
  size_t len;
  struct dirlist *next;
};

struct filelist
{
  char *name;
  Dwarf_Unsigned mtime;
  Dwarf_Unsigned length;
  struct filelist *next;
};


static int
read_file_names (Dwarf_Debug dbg, char *comp_dir, Dwarf_Small **linepp,
		 char ***result, Dwarf_Signed *nresult, Dwarf_Error *error)
{
  Dwarf_Small *linep = *linepp;
  struct dirlist comp_dir_elem;
  struct dirlist *dirlist;
  unsigned int ndirlist;
  struct dirlist **dirarray;
  struct filelist *filelist = NULL;
  unsigned int nfilelist = 0;

  /* First comes the list of directories.  Add the compilation directory
     first since the index zero is used for it.  */
  comp_dir_elem.dir = comp_dir;
  comp_dir_elem.len = comp_dir ? strlen (comp_dir) : 0;
  comp_dir_elem.next = NULL;
  dirlist = &comp_dir_elem;
  ndirlist = 1;

  while (*linep != 0)
    {
      struct dirlist *new_dir = (struct dirlist *) alloca (sizeof (*new_dir));

      new_dir->dir = (char *) linep;
      new_dir->len = strlen ((char *) linep);
      new_dir->next = dirlist;
      dirlist = new_dir;
      ++ndirlist;
      linep += new_dir->len + 1;
    }
  /* Skip the final NUL byte.  */
  ++linep;

  /* Rearrange the list in array form.  */
  dirarray = (struct dirlist **) alloca (sizeof (*dirarray));
  while (ndirlist-- > 0)
    {
      dirarray[ndirlist] = dirlist;
      dirlist = dirlist->next;
    }

  /* Now read the files.  */
  while (*linep != 0)
    {
      struct filelist *new_file =
	(struct filelist *) alloca (sizeof (*new_file));
      char *fname;
      size_t fnamelen;
      Dwarf_Unsigned diridx;

      /* First comes the file name.  */
      fname = (char *) linep;
      fnamelen = strlen (fname);
      linep += fnamelen + 1;

      /* Then the index.  */
      get_uleb128 (diridx, linep);
      if (unlikely (diridx >= ndirlist))
	{
	  __libdwarf_error (dbg, error, DW_E_INVALID_DIR_IDX);
	  return DW_DLV_ERROR;
	}

      if (*fname == '/')
	/* It's an absolute path.  */
	new_file->name = strdup (fname);
      else
	{
	  new_file->name = (char *) malloc (dirarray[diridx]->len + 1
					    + fnamelen + 1);
	  if (new_file->name != NULL)
	    {
	      char *cp = new_file->name;

	      if (dirarray[diridx]->dir != NULL)
		/* This value could be NULL in case the DW_AT_comp_dir
		   was not present.  We cannot do much in this case.
		   The easiest thing is to convert the path in an
		   absolute path.  */
		cp = stpcpy (cp, dirarray[diridx]->dir);
	      *cp++ = '/';
	      strcpy (cp, fname);
	    }
	}
      if (new_file->name == NULL)
	{
	  /* XXX Should we bother to free all the memory?  */
	  __libdwarf_error (dbg, error, DW_E_NOMEM);
	  return DW_DLV_ERROR;
	}

      /* Next comes the modification time.  */
      get_uleb128 (new_file->mtime, linep);

      /* Finally the length of the file.  */
      get_uleb128 (new_file->length, linep);

      new_file->next = filelist;
      filelist = new_file;
      ++nfilelist;
    }

  /* Put all the files in an array.  */
  *result = (char **) malloc (nfilelist * sizeof (char *));
  if (*result == NULL)
    {
      /* XXX Should we bother to free all the memory?  */
      __libdwarf_error (dbg, error, DW_E_NOMEM);
      return DW_DLV_ERROR;
    }

  *nresult = nfilelist;
  while (nfilelist-- > 0)
    {
      (*result)[nfilelist] = filelist->name;
      filelist = filelist->next;
    }

  /* Provide caller address of next byte.  */
  *linepp = linep + 1;

  return DW_DLV_OK;
}


int
dwarf_srcfiles (die, srcfiles, srcfilecount, error)
     Dwarf_Die die;
     char ***srcfiles;
     Dwarf_Signed *srcfilecount;
     Dwarf_Error *error;
{
  Dwarf_CU_Info cu = die->cu;
  Dwarf_Debug dbg = cu->dbg;
  Dwarf_Attribute stmt_list;
  Dwarf_Attribute comp_dir_attr;
  char *comp_dir;
  Dwarf_Unsigned offset;
  Dwarf_Small *linep;
  Dwarf_Small *lineendp;
  Dwarf_Small *header_start;
  Dwarf_Unsigned header_length;
  unsigned int unit_length;
  unsigned int version;
  unsigned int opcode_base;
  int length;
  int res;

  /* For now we haven't found anything.  */
  *srcfilecount = 0;

  /* The die must be for a compilation unit.  */
  if (die->abbrev->tag != DW_TAG_compile_unit)
    {
      __libdwarf_error (die->cu->dbg, error, DW_E_NO_CU);
      return DW_DLV_ERROR;
    }

  /* The die must have a statement list associated.  */
  res = dwarf_attr (die, DW_AT_stmt_list, &stmt_list, error);
  if (res != DW_DLV_OK)
    return res;

  /* Get the offset into the .debug_line section.  */
  res = dwarf_formudata (stmt_list, &offset, error);
  if (res != DW_DLV_OK)
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      return res;
    }

  /* We need a .debug_line section.  */
  if (dbg->sections[IDX_debug_line].addr == NULL)
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_NO_DEBUG_LINE);
      return DW_DLV_ERROR;
    }

  linep = (Dwarf_Small *) dbg->sections[IDX_debug_line].addr + offset;
  lineendp = ((Dwarf_Small *) dbg->sections[IDX_debug_line].addr
	      + dbg->sections[IDX_debug_line].size);

  /* Test whether at least the first 4 bytes are available.  */
  if (unlikely (linep + 4 > lineendp))
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }

  /* Get the compilation directory.  */
  res = dwarf_attr (die, DW_AT_comp_dir, &comp_dir_attr, error);
  if (unlikely (res == DW_DLV_ERROR)
      || (res == DW_DLV_OK
	  && unlikely (dwarf_formstring (comp_dir_attr, &comp_dir, error)
		       == DW_DLV_ERROR)))
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }
  else if (res == DW_DLV_OK)
    dwarf_dealloc (dbg, comp_dir_attr, DW_DLA_ATTR);
  else
    comp_dir = NULL;

  /* Read the unit_length.  */
  unit_length = read_4ubyte_unaligned (dbg, linep);
  linep += 4;
  length = 4;
  if (unit_length == 0xffffffff)
    {
      if (unlikely (linep + 8 > lineendp))
	{
	  dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
	  __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
	  return DW_DLV_ERROR;
	}

      unit_length = read_8ubyte_unaligned (dbg, linep);
      linep += 8;
      length = 8;
    }

  /* Check whether we have enough room in the section.  */
  if (unlikely (linep + unit_length > lineendp))
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }
  lineendp = linep + unit_length;

  /* The next element of the header is the version identifier.  */
  version = read_2ubyte_unaligned (dbg, linep);
  if (unlikely (version != DWARF_VERSION))
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_VERSION_ERROR);
      return DW_DLV_ERROR;
    }
  linep += 2;

  /* Next comes the header length.  */
  if (length == 4)
    {
      header_length = read_4ubyte_unaligned (dbg, linep);
      linep += 4;
    }
  else
    {
      header_length = read_8ubyte_unaligned (dbg, linep);
      linep += 8;
    }
  header_start = linep;

  /* Next the minimum instruction length.  Skip it.  */
  ++linep;

  /* Then the flag determining the default value of the is_stmt
     register.  Skip it.  */
  ++linep;

  /* Now the line base.  Skip it.  */
  ++linep;

  /* And the line range.  Skip it.  */
  ++linep;

  /* The opcode base.  */
  opcode_base = *linep++;

  /* Skip the array with the standard opcode length.  */
  linep += opcode_base - 1;

  /* Next the include directories and the file names.  */
  if (unlikely (read_file_names (dbg, comp_dir, &linep, srcfiles, srcfilecount,
				 error) != DW_DLV_OK))
    {
      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      return DW_DLV_ERROR;
    }

  /* Consistency check.  */
  if (unlikely (linep != header_start + header_length))
    {
      int i;

      for (i = 0; i < *srcfilecount; ++i)
	dwarf_dealloc (dbg, (*srcfiles)[i], DW_DLA_STRING);
      dwarf_dealloc (dbg, *srcfiles, DW_DLA_LIST);

      dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);
      __libdwarf_error (dbg, error, DW_E_INVALID_DWARF);
      return DW_DLV_ERROR;
    }

  dwarf_dealloc (dbg, stmt_list, DW_DLA_ATTR);

  return DW_DLV_OK;
}