dl-librecon.h

Newlib 嵌入式 C库 标准实现代码

/* Optional code to distinguish library flavours.
   Copyright (C) 1998, 2001 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <[e-mail]>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#ifndef _DL_LIBRECON_H
#define _DL_LIBRECON_H	1

#define DISTINGUISH_LIB_VERSIONS \
  do									      \
    {									      \
      /* We have to find out whether the binary is linked against	      \
	 libc 5 or glibc.  We do this by looking at all the DT_NEEDED	      \
	 entries.  If one is libc.so.5 this is a libc 5 linked binary.  */    \
      if (_dl_loaded->l_info[DT_NEEDED])				      \
	{								      \
	  /* We have dependencies.  */					      \
	  const ElfW(Dyn) *d;						      \
	  const char *strtab;						      \
									      \
	  strtab = (const char *) D_PTR (_dl_loaded, l_info[DT_STRTAB]);      \
									      \
	  for (d = _dl_loaded->l_ld; d->d_tag != DT_NULL; ++d)		      \
	    if (d->d_tag == DT_NEEDED					      \
		&& strcmp (strtab + d->d_un.d_val, "libc.so.5") == 0)	      \
	      break;							      \
									      \
	  /* We print a `5' or `6' depending on the outcome.  */	      \
	  _dl_printf (d->d_tag != DT_NULL ? "5\n" : "6\n");		      \
	}								      \
    }									      \
  while (0)

/* Recognizing extra environment variables.  */
#define EXTRA_LD_ENVVARS \
  case 13:								      \
    if (memcmp (envline, "ASSUME_KERNEL", 13) == 0)			      \
      {									      \
	unsigned long int i, j, osversion = 0;				      \
	char *p = &envline[14], *q;					      \
									      \
	for (i = 0; i < 3; i++, p = q + 1)				      \
	  {								      \
	    j = __strtoul_internal (p, &q, 0, 0);			      \
	    if (j >= 255 || p == q || (i < 2 && *q && *q != '.'))	      \
	      {								      \
		osversion = 0;						      \
		break;							      \
	      }								      \
	    osversion |= j << (16 - 8 * i);				      \
	    if (!*q)							      \
	      break;							      \
	  }								      \
	if (osversion)							      \
	  _dl_osversion = osversion;					      \
	break;								      \
      }									      \
									      \
  case 15:								      \
    if (memcmp (envline, "LIBRARY_VERSION", 15) == 0)			      \
      {									      \
	_dl_correct_cache_id = envline[16] == '5' ? 2 : 3;		      \
	break;								      \
      }

/* Extra unsecure variables.  The names are all stuffed in a single
   string which means they have to be terminated with a '\0' explicitly.  */
#define EXTRA_UNSECURE_ENVVARS \
  "LD_AOUT_LIBRARY_PATH\0"						      \
  "LD_AOUT_PRELOAD\0"

#endif /* dl-librecon.h */