/* Set up the data structures for the system-supplied DSO.

   Copyright (C) 2012-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   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, see

   <http://www.gnu.org/licenses/>.  */

static inline void __attribute__ ((always_inline))

setup_vdso (struct link_map *main_map __attribute__ ((unused)),

	    struct link_map ***first_preload __attribute__ ((unused)))

{

#ifdef NEED_DL_SYSINFO_DSO

  if (GLRO(dl_sysinfo_dso) == NULL)

    return;

  /* Do an abridged version of the work _dl_map_object_from_fd would do

     to map in the object.  It's already mapped and prelinked (and

     better be, since it's read-only and so we couldn't relocate it).

     We just want our data structures to describe it as if we had just

     mapped and relocated it normally.  */

  struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,

				       0, LM_ID_BASE);

  if (__glibc_likely (l != NULL))

    {

      static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;

      l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)

		   + GLRO(dl_sysinfo_dso)->e_phoff);

      l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;

      for (uint_fast16_t i = 0; i < l->l_phnum; ++i)

	{

	  const ElfW(Phdr) *const ph = &l->l_phdr[i];

	  if (ph->p_type == PT_DYNAMIC)

	    {

	      l->l_ld = (void *) ph->p_vaddr;

	      l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));

	    }

	  else if (ph->p_type == PT_LOAD)

	    {

	      if (! l->l_addr)

		l->l_addr = ph->p_vaddr;

	      if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)

		l->l_map_end = ph->p_vaddr + ph->p_memsz;

	      if ((ph->p_flags & PF_X)

		  && ph->p_vaddr + ph->p_memsz >= l->l_text_end)

		l->l_text_end = ph->p_vaddr + ph->p_memsz;

	    }

	  else

	    /* There must be no TLS segment.  */

	    assert (ph->p_type != PT_TLS);

	}

      l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);

      l->l_addr = l->l_map_start - l->l_addr;

      l->l_map_end += l->l_addr;

      l->l_text_end += l->l_addr;

      l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);

      elf_get_dynamic_info (l, dyn_temp);

      _dl_setup_hash (l);

      l->l_relocated = 1;

      /* The vDSO is always used.  */

      l->l_used = 1;

      /* Initialize l_local_scope to contain just this map.  This allows

	 the use of dl_lookup_symbol_x to resolve symbols within the vdso.

	 So we create a single entry list pointing to l_real as its only

	 element */

      l->l_local_scope[0]->r_nlist = 1;

      l->l_local_scope[0]->r_list = &l->l_real;

      /* Now that we have the info handy, use the DSO image's soname

	 so this object can be looked up by name.  Note that we do not

	 set l_name here.  That field gives the file name of the DSO,

	 and this DSO is not associated with any file.  */

      if (l->l_info[DT_SONAME] != NULL)

	{

	  /* Work around a kernel problem.  The kernel cannot handle

	     addresses in the vsyscall DSO pages in writev() calls.  */

	  const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB])

				 + l->l_info[DT_SONAME]->d_un.d_val);

	  size_t len = strlen (dsoname) + 1;

	  char *copy = malloc (len);

	  if (copy == NULL)

	    _dl_fatal_printf ("out of memory\n");

	  l->l_libname->name = l->l_name = memcpy (copy, dsoname, len);

	}

      /* Add the vDSO to the object list.  */

      _dl_add_to_namespace_list (l, LM_ID_BASE);

# if IS_IN (rtld)

      /* Rearrange the list so this DSO appears after rtld_map.  */

      assert (l->l_next == NULL);

      assert (l->l_prev == main_map);

      GL(dl_rtld_map).l_next = l;

      l->l_prev = &GL(dl_rtld_map);

      *first_preload = &l->l_next;

# else

      GL(dl_nns) = 1;

# endif

      /* We have a prelinked DSO preloaded by the system.  */

      GLRO(dl_sysinfo_map) = l;

# ifdef NEED_DL_SYSINFO

      if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT)

	GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr;

# endif

    }

#endif

}