libdwarf/dwarf_srcfiles.c

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

   This program is Open Source software; you can redistribute it and/or
   modify it under the terms of the Open Software License version 1.0 as
   published by the Open Source Initiative.

   You should have received a copy of the Open Software License along
   with this program; if not, you may obtain a copy of the Open Software
   License version 1.0 from http://www.opensource.org/licenses/osl.php or
   by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
   3001 King Ranch Road, Ukiah, CA 95482.   */

#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;
}