/* Storage management for the chain of loaded shared objects.

   Copyright (C) 1995-2018 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/>.  */

#include <errno.h>

#include <string.h>

#include <stdlib.h>

#include <unistd.h>

#include <ldsodefs.h>

#include <assert.h>

/* Add the new link_map NEW to the end of the namespace list.  */

void

_dl_add_to_namespace_list (struct link_map *new, Lmid_t nsid)

{

  /* We modify the list of loaded objects.  */

  __rtld_lock_lock_recursive (GL(dl_load_write_lock));

  if (GL(dl_ns)[nsid]._ns_loaded != NULL)

    {

      struct link_map *l = GL(dl_ns)[nsid]._ns_loaded;

      while (l->l_next != NULL)

	l = l->l_next;

      new->l_prev = l;

      /* new->l_next = NULL;   Would be necessary but we use calloc.  */

      l->l_next = new;

    }

  else

    GL(dl_ns)[nsid]._ns_loaded = new;

  ++GL(dl_ns)[nsid]._ns_nloaded;

  new->l_serial = GL(dl_load_adds);

  ++GL(dl_load_adds);

  __rtld_lock_unlock_recursive (GL(dl_load_write_lock));

}

/* Allocate a `struct link_map' for a new object being loaded,

   and enter it into the _dl_loaded list.  */

struct link_map *

_dl_new_object (char *realname, const char *libname, int type,

		struct link_map *loader, int mode, Lmid_t nsid)

{

  size_t libname_len = strlen (libname) + 1;

  struct link_map *new;

  struct libname_list *newname;

#ifdef SHARED

  /* We create the map for the executable before we know whether we have

     auditing libraries and if yes, how many.  Assume the worst.  */

  unsigned int naudit = GLRO(dl_naudit) ?: ((mode & __RTLD_OPENEXEC)

					    ? DL_NNS : 0);

  size_t audit_space = naudit * sizeof (new->l_audit[0]);

#else

# define audit_space 0

#endif

  new = (struct link_map *) calloc (sizeof (*new) + audit_space

				    + sizeof (struct link_map *)

				    + sizeof (*newname) + libname_len, 1);

  if (new == NULL)

    return NULL;

  new->l_real = new;

  new->l_symbolic_searchlist.r_list = (struct link_map **) ((char *) (new + 1)

							    + audit_space);

  new->l_libname = newname

    = (struct libname_list *) (new->l_symbolic_searchlist.r_list + 1);

  newname->name = (char *) memcpy (newname + 1, libname, libname_len);

  /* newname->next = NULL;	We use calloc therefore not necessary.  */

  newname->dont_free = 1;

  /* When we create the executable link map, or a VDSO link map, we start

     with "" for the l_name. In these cases "" points to ld.so rodata

     and won't get dumped during core file generation. Therefore to assist

     gdb and to create more self-contained core files we adjust l_name to

     point at the newly allocated copy (which will get dumped) instead of

     the ld.so rodata copy.  */

  new->l_name = *realname ? realname : (char *) newname->name + libname_len - 1;

  new->l_type = type;

  /* If we set the bit now since we know it is never used we avoid

     dirtying the cache line later.  */

  if ((GLRO(dl_debug_mask) & DL_DEBUG_UNUSED) == 0)

    new->l_used = 1;

  new->l_loader = loader;

#if NO_TLS_OFFSET != 0

  new->l_tls_offset = NO_TLS_OFFSET;

#endif

  new->l_ns = nsid;

#ifdef SHARED

  for (unsigned int cnt = 0; cnt < naudit; ++cnt)

    {

      new->l_audit[cnt].cookie = (uintptr_t) new;

      /* new->l_audit[cnt].bindflags = 0; */

    }

#endif

  /* new->l_global = 0;	We use calloc therefore not necessary.  */

  /* Use the 'l_scope_mem' array by default for the 'l_scope'

     information.  If we need more entries we will allocate a large

     array dynamically.  */

  new->l_scope = new->l_scope_mem;

  new->l_scope_max = sizeof (new->l_scope_mem) / sizeof (new->l_scope_mem[0]);

  /* Counter for the scopes we have to handle.  */

  int idx = 0;

  if (GL(dl_ns)[nsid]._ns_loaded != NULL)

    /* Add the global scope.  */

    new->l_scope[idx++] = &GL(dl_ns)[nsid]._ns_loaded->l_searchlist;

  /* If we have no loader the new object acts as it.  */

  if (loader == NULL)

    loader = new;

  else

    /* Determine the local scope.  */

    while (loader->l_loader != NULL)

      loader = loader->l_loader;

  /* Insert the scope if it isn't the global scope we already added.  */

  if (idx == 0 || &loader->l_searchlist != new->l_scope[0])

    {

      if ((mode & RTLD_DEEPBIND) != 0 && idx != 0)

	{

	  new->l_scope[1] = new->l_scope[0];

	  idx = 0;

	}

      new->l_scope[idx] = &loader->l_searchlist;

    }

  new->l_local_scope[0] = &new->l_searchlist;

  /* Don't try to find the origin for the main map which has the name "".  */

  if (realname[0] != '\0')

    {

      size_t realname_len = strlen (realname) + 1;

      char *origin;

      char *cp;

      if (realname[0] == '/')

	{

	  /* It is an absolute path.  Use it.  But we have to make a

	     copy since we strip out the trailing slash.  */

	  cp = origin = (char *) malloc (realname_len);

	  if (origin == NULL)

	    {

	      origin = (char *) -1;

	      goto out;

	    }

	}

      else

	{

	  size_t len = realname_len;

	  char *result = NULL;

	  /* Get the current directory name.  */

	  origin = NULL;

	  do

	    {

	      char *new_origin;

	      len += 128;

	      new_origin = (char *) realloc (origin, len);

	      if (new_origin == NULL)

		/* We exit the loop.  Note that result == NULL.  */

		break;

	      origin = new_origin;

	    }

	  while ((result = __getcwd (origin, len - realname_len)) == NULL

		 && errno == ERANGE);

	  if (result == NULL)

	    {

	      /* We were not able to determine the current directory.

		 Note that free(origin) is OK if origin == NULL.  */

	      free (origin);

	      origin = (char *) -1;

	      goto out;

	    }

	  /* Find the end of the path and see whether we have to add a

	     slash.  We could use rawmemchr but this need not be

	     fast.  */

	  cp = (strchr) (origin, '\0');

	  if (cp[-1] != '/')

	    *cp++ = '/';

	}

      /* Add the real file name.  */

      cp = __mempcpy (cp, realname, realname_len);

      /* Now remove the filename and the slash.  Leave the slash if

	 the name is something like "/foo".  */

      do

	--cp;

      while (*cp != '/');

      if (cp == origin)

	/* Keep the only slash which is the first character.  */

	++cp;

      *cp = '\0';

    out:

      new->l_origin = origin;

    }

  return new;

}