/* Copyright (C) 2011-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.

   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/>.  */

#define E(name) E_(name, CLASS)

#define E_(name, cl) E__(name, cl)

#define E__(name, cl) name##cl

#define EW(type) EW_(Elf, CLASS, type)

#define EW_(e, w, t) EW__(e, w, _##t)

#define EW__(e, w, t) e##w##t

struct E(link_map)

{

  EW(Addr) l_addr;

  EW(Addr) l_name;

  EW(Addr) l_ld;

  EW(Addr) l_next;

  EW(Addr) l_prev;

  EW(Addr) l_real;

  Lmid_t l_ns;

  EW(Addr) l_libname;

};

#if CLASS == __ELF_NATIVE_CLASS

_Static_assert (offsetof (struct link_map, l_addr)

               == offsetof (struct E(link_map), l_addr), "l_addr");

_Static_assert (offsetof (struct link_map, l_name)

               == offsetof (struct E(link_map), l_name), "l_name");

_Static_assert (offsetof (struct link_map, l_next)

               == offsetof (struct E(link_map), l_next), "l_next");

#endif

struct E(libname_list)

{

  EW(Addr) name;

  EW(Addr) next;

};

#if CLASS == __ELF_NATIVE_CLASS

_Static_assert (offsetof (struct libname_list, name)

               == offsetof (struct E(libname_list), name), "name");

_Static_assert (offsetof (struct libname_list, next)

               == offsetof (struct E(libname_list), next), "next");

#endif

struct E(r_debug)

{

  int r_version;

#if CLASS == 64

  int pad;

#endif

  EW(Addr) r_map;

};

#if CLASS == __ELF_NATIVE_CLASS

_Static_assert (offsetof (struct r_debug, r_version)

               == offsetof (struct E(r_debug), r_version), "r_version");

_Static_assert (offsetof (struct r_debug, r_map)

               == offsetof (struct E(r_debug), r_map), "r_map");

#endif

static int

E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,

             size_t auxv_size)

{

  EW(Addr) phdr = 0;

  unsigned int phnum = 0;

  unsigned int phent = 0;

  EW(auxv_t) *auxvXX = (EW(auxv_t) *) auxv;

  for (int i = 0; i < auxv_size / sizeof (EW(auxv_t)); ++i)

    switch (auxvXX[i].a_type)

      {

      case AT_PHDR:

	phdr = auxvXX[i].a_un.a_val;

	break;

      case AT_PHNUM:

	phnum = auxvXX[i].a_un.a_val;

	break;

      case AT_PHENT:

	phent = auxvXX[i].a_un.a_val;

	break;

      default:

	break;

      }

  if (phdr == 0 || phnum == 0 || phent == 0)

    error (EXIT_FAILURE, 0, gettext ("cannot find program header of process"));

  EW(Phdr) *p = xmalloc (phnum * phent);

  if (pread (memfd, p, phnum * phent, phdr) != phnum * phent)

    error (EXIT_FAILURE, 0, gettext ("cannot read program header"));

  /* Determine the load offset.  We need this for interpreting the

     other program header entries so we do this in a separate loop.

     Fortunately it is the first time unless someone does something

     stupid when linking the application.  */

  EW(Addr) offset = 0;

  for (unsigned int i = 0; i < phnum; ++i)

    if (p[i].p_type == PT_PHDR)

      {

	offset = phdr - p[i].p_vaddr;

	break;

      }

  EW(Addr) list = 0;

  char *interp = NULL;

  for (unsigned int i = 0; i < phnum; ++i)

    if (p[i].p_type == PT_DYNAMIC)

      {

	EW(Dyn) *dyn = xmalloc (p[i].p_filesz);

       if (pread (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)

	    != p[i].p_filesz)

         error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));

	/* Search for the DT_DEBUG entry.  */

	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)

	  if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)

	    {

	      struct E(r_debug) r;

             if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)

		  != sizeof (r))

               error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));

	      if (r.r_map != 0)

		{

		  list = r.r_map;

		  break;

		}

	    }

	free (dyn);

	break;

      }

    else if (p[i].p_type == PT_INTERP)

      {

       interp = xmalloc (p[i].p_filesz);

       if (pread (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)

	    != p[i].p_filesz)

         error (EXIT_FAILURE, 0, gettext ("cannot read program interpreter"));

      }

  if (list == 0)

    {

      if (interp == NULL)

	{

	  // XXX check whether the executable itself is the loader

         exit (EXIT_FAILURE);

	}

      // XXX perhaps try finding ld.so and _r_debug in it

      exit (EXIT_FAILURE);

    }

  free (p);

  free (interp);

  /* Print the PID and program name first.  */

  printf ("%lu:\t%s\n", (unsigned long int) pid, exe);

  /* Iterate over the list of objects and print the information.  */

  struct scratch_buffer tmpbuf;

  scratch_buffer_init (&tmpbuf);

  int status = 0;

  do

    {

      struct E(link_map) m;

      if (pread (memfd, &m, sizeof (m), list) != sizeof (m))

       error (EXIT_FAILURE, 0, gettext ("cannot read link map"));

      EW(Addr) name_offset = m.l_name;

      while (1)

	{

         ssize_t n = pread (memfd, tmpbuf.data, tmpbuf.length, name_offset);

	  if (n == -1)

           error (EXIT_FAILURE, 0, gettext ("cannot read object name"));

	  if (memchr (tmpbuf.data, '\0', n) != NULL)

	    break;

	  if (!scratch_buffer_grow (&tmpbuf))

           error (EXIT_FAILURE, 0,

                  gettext ("cannot allocate buffer for object name"));

	}

      /* The m.l_name and m.l_libname.name for loader linkmap points to same

        values (since BZ#387 fix).  Trying to use l_libname name as the

        shared object name might lead to an infinite loop (BZ#18035).  */

      /* Skip over the executable.  */

      if (((char *)tmpbuf.data)[0] != '\0')

	printf ("%s\n", (char *)tmpbuf.data);

      list = m.l_next;

    }

  while (list != 0);

  scratch_buffer_free (&tmpbuf);

  return status;

}

#undef CLASS