/* Load a shared object at runtime, relocate it, and run its initializer.

   Copyright (C) 1996-2018 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 <assert.h>

#include <dlfcn.h>

#include <errno.h>

#include <libintl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <sys/mman.h>		/* Check whether MAP_COPY is defined.  */

#include <sys/param.h>

#include <libc-lock.h>

#include <ldsodefs.h>

#include <sysdep-cancel.h>

#include <tls.h>

#include <stap-probe.h>

#include <atomic.h>

#include <libc-internal.h>

#include <dl-dst.h>

#include <dl-prop.h>

/* We must be careful not to leave us in an inconsistent state.  Thus we

   catch any error and re-raise it after cleaning up.  */

struct dl_open_args

{

  const char *file;

  int mode;

  /* This is the caller of the dlopen() function.  */

  const void *caller_dlopen;

  struct link_map *map;

  /* Namespace ID.  */

  Lmid_t nsid;

  /* Original parameters to the program and the current environment.  */

  int argc;

  char **argv;

  char **env;

};

static int

add_to_global (struct link_map *new)

{

  struct link_map **new_global;

  unsigned int to_add = 0;

  unsigned int cnt;

  /* Count the objects we have to put in the global scope.  */

  for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)

    if (new->l_searchlist.r_list[cnt]->l_global == 0)

      ++to_add;

  /* The symbols of the new objects and its dependencies are to be

     introduced into the global scope that will be used to resolve

     references from other dynamically-loaded objects.

     The global scope is the searchlist in the main link map.  We

     extend this list if necessary.  There is one problem though:

     since this structure was allocated very early (before the libc

     is loaded) the memory it uses is allocated by the malloc()-stub

     in the ld.so.  When we come here these functions are not used

     anymore.  Instead the malloc() implementation of the libc is

     used.  But this means the block from the main map cannot be used

     in an realloc() call.  Therefore we allocate a completely new

     array the first time we have to add something to the locale scope.  */

  struct link_namespaces *ns = &GL(dl_ns)[new->l_ns];

  if (ns->_ns_global_scope_alloc == 0)

    {

      /* This is the first dynamic object given global scope.  */

      ns->_ns_global_scope_alloc

	= ns->_ns_main_searchlist->r_nlist + to_add + 8;

      new_global = (struct link_map **)

	malloc (ns->_ns_global_scope_alloc * sizeof (struct link_map *));

      if (new_global == NULL)

	{

	  ns->_ns_global_scope_alloc = 0;

	nomem:

	  _dl_signal_error (ENOMEM, new->l_libname->name, NULL,

			    N_("cannot extend global scope"));

	  return 1;

	}

      /* Copy over the old entries.  */

      ns->_ns_main_searchlist->r_list

	= memcpy (new_global, ns->_ns_main_searchlist->r_list,

		  (ns->_ns_main_searchlist->r_nlist

		   * sizeof (struct link_map *)));

    }

  else if (ns->_ns_main_searchlist->r_nlist + to_add

	   > ns->_ns_global_scope_alloc)

    {

      /* We have to extend the existing array of link maps in the

	 main map.  */

      struct link_map **old_global

	= GL(dl_ns)[new->l_ns]._ns_main_searchlist->r_list;

      size_t new_nalloc = ((ns->_ns_global_scope_alloc + to_add) * 2);

      new_global = (struct link_map **)

	malloc (new_nalloc * sizeof (struct link_map *));

      if (new_global == NULL)

	goto nomem;

      memcpy (new_global, old_global,

	      ns->_ns_global_scope_alloc * sizeof (struct link_map *));

      ns->_ns_global_scope_alloc = new_nalloc;

      ns->_ns_main_searchlist->r_list = new_global;

      if (!RTLD_SINGLE_THREAD_P)

	THREAD_GSCOPE_WAIT ();

      free (old_global);

    }

  /* Now add the new entries.  */

  unsigned int new_nlist = ns->_ns_main_searchlist->r_nlist;

  for (cnt = 0; cnt < new->l_searchlist.r_nlist; ++cnt)

    {

      struct link_map *map = new->l_searchlist.r_list[cnt];

      if (map->l_global == 0)

	{

	  map->l_global = 1;

	  ns->_ns_main_searchlist->r_list[new_nlist++] = map;

	  /* We modify the global scope.  Report this.  */

	  if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))

	    _dl_debug_printf ("\nadd %s [%lu] to global scope\n",

			      map->l_name, map->l_ns);

	}

    }

  atomic_write_barrier ();

  ns->_ns_main_searchlist->r_nlist = new_nlist;

  return 0;

}

/* Search link maps in all namespaces for the DSO that contains the object at

   address ADDR.  Returns the pointer to the link map of the matching DSO, or

   NULL if a match is not found.  */

struct link_map *

_dl_find_dso_for_object (const ElfW(Addr) addr)

{

  struct link_map *l;

  /* Find the highest-addressed object that ADDR is not below.  */

  for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)

    for (l = GL(dl_ns)[ns]._ns_loaded; l != NULL; l = l->l_next)

      if (addr >= l->l_map_start && addr < l->l_map_end

	  && (l->l_contiguous

	      || _dl_addr_inside_object (l, (ElfW(Addr)) addr)))

	{

	  assert (ns == l->l_ns);

	  return l;

	}

  return NULL;

}

rtld_hidden_def (_dl_find_dso_for_object);

static void

dl_open_worker (void *a)

{

  struct dl_open_args *args = a;

  const char *file = args->file;

  int mode = args->mode;

  struct link_map *call_map = NULL;

  /* Determine the caller's map if necessary.  This is needed in case

     we have a DST, when we don't know the namespace ID we have to put

     the new object in, or when the file name has no path in which

     case we need to look along the RUNPATH/RPATH of the caller.  */

  const char *dst = strchr (file, '$');

  if (dst != NULL || args->nsid == __LM_ID_CALLER

      || strchr (file, '/') == NULL)

    {

      const void *caller_dlopen = args->caller_dlopen;

      /* We have to find out from which object the caller is calling.

	 By default we assume this is the main application.  */

      call_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;

      struct link_map *l = _dl_find_dso_for_object ((ElfW(Addr)) caller_dlopen);

      if (l)

	call_map = l;

      if (args->nsid == __LM_ID_CALLER)

	args->nsid = call_map->l_ns;

    }

  /* One might be tempted to assert that we are RT_CONSISTENT at this point, but that

     may not be true if this is a recursive call to dlopen.  */

  _dl_debug_initialize (0, args->nsid);

  /* Load the named object.  */

  struct link_map *new;

  args->map = new = _dl_map_object (call_map, file, lt_loaded, 0,

				    mode | __RTLD_CALLMAP, args->nsid);

  /* If the pointer returned is NULL this means the RTLD_NOLOAD flag is

     set and the object is not already loaded.  */

  if (new == NULL)

    {

      assert (mode & RTLD_NOLOAD);

      return;

    }

  /* Mark the object as not deletable if the RTLD_NODELETE flags was passed.

     Do this early so that we don't skip marking the object if it was

     already loaded.  */

  if (__glibc_unlikely (mode & RTLD_NODELETE))

    new->l_flags_1 |= DF_1_NODELETE;

  if (__glibc_unlikely (mode & __RTLD_SPROF))

    /* This happens only if we load a DSO for 'sprof'.  */

    return;

  /* This object is directly loaded.  */

  ++new->l_direct_opencount;

  /* It was already open.  */

  if (__glibc_unlikely (new->l_searchlist.r_list != NULL))

    {

      /* Let the user know about the opencount.  */

      if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))

	_dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",

			  new->l_name, new->l_ns, new->l_direct_opencount);

      /* If the user requested the object to be in the global namespace

	 but it is not so far, add it now.  */

      if ((mode & RTLD_GLOBAL) && new->l_global == 0)

	(void) add_to_global (new);

      assert (_dl_debug_initialize (0, args->nsid)->r_state == RT_CONSISTENT);

      return;

    }

  /* Load that object's dependencies.  */

  _dl_map_object_deps (new, NULL, 0, 0,

		       mode & (__RTLD_DLOPEN | RTLD_DEEPBIND | __RTLD_AUDIT));

  /* So far, so good.  Now check the versions.  */

  for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i)

    if (new->l_searchlist.r_list[i]->l_real->l_versions == NULL)

      (void) _dl_check_map_versions (new->l_searchlist.r_list[i]->l_real,

				     0, 0);

#ifdef SHARED

  /* Auditing checkpoint: we have added all objects.  */

  if (__glibc_unlikely (GLRO(dl_naudit) > 0))

    {

      struct link_map *head = GL(dl_ns)[new->l_ns]._ns_loaded;

      /* Do not call the functions for any auditing object.  */

      if (head->l_auditing == 0)

	{

	  struct audit_ifaces *afct = GLRO(dl_audit);

	  for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)

	    {

	      if (afct->activity != NULL)

		afct->activity (&head->l_audit[cnt].cookie, LA_ACT_CONSISTENT);

	      afct = afct->next;

	    }

	}

    }

#endif

  /* Notify the debugger all new objects are now ready to go.  */

  struct r_debug *r = _dl_debug_initialize (0, args->nsid);

  r->r_state = RT_CONSISTENT;

  _dl_debug_state ();

  LIBC_PROBE (map_complete, 3, args->nsid, r, new);

  /* Print scope information.  */

  if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))

    _dl_show_scope (new, 0);

  /* Only do lazy relocation if `LD_BIND_NOW' is not set.  */

  int reloc_mode = mode & __RTLD_AUDIT;

  if (GLRO(dl_lazy))

    reloc_mode |= mode & RTLD_LAZY;

  /* Sort the objects by dependency for the relocation process.  This

     allows IFUNC relocations to work and it also means copy

     relocation of dependencies are if necessary overwritten.  */

  unsigned int nmaps = 0;

  struct link_map *l = new;

  do

    {

      if (! l->l_real->l_relocated)

	++nmaps;

      l = l->l_next;

    }

  while (l != NULL);

  struct link_map *maps[nmaps];

  nmaps = 0;

  l = new;

  do

    {

      if (! l->l_real->l_relocated)

	maps[nmaps++] = l;

      l = l->l_next;

    }

  while (l != NULL);

  _dl_sort_maps (maps, nmaps, NULL, false);

  int relocation_in_progress = 0;

  for (unsigned int i = nmaps; i-- > 0; )

    {

      l = maps[i];

      if (! relocation_in_progress)

	{

	  /* Notify the debugger that relocations are about to happen.  */

	  LIBC_PROBE (reloc_start, 2, args->nsid, r);

	  relocation_in_progress = 1;

	}

#ifdef SHARED

      if (__glibc_unlikely (GLRO(dl_profile) != NULL))

	{

	  /* If this here is the shared object which we want to profile

	     make sure the profile is started.  We can find out whether

	     this is necessary or not by observing the `_dl_profile_map'

	     variable.  If it was NULL but is not NULL afterwards we must

	     start the profiling.  */

	  struct link_map *old_profile_map = GL(dl_profile_map);

	  _dl_relocate_object (l, l->l_scope, reloc_mode | RTLD_LAZY, 1);

	  if (old_profile_map == NULL && GL(dl_profile_map) != NULL)

	    {

	      /* We must prepare the profiling.  */

	      _dl_start_profile ();

	      /* Prevent unloading the object.  */

	      GL(dl_profile_map)->l_flags_1 |= DF_1_NODELETE;

	    }

	}

      else

#endif

	_dl_relocate_object (l, l->l_scope, reloc_mode, 0);

    }

  /* NB: Workaround for [BZ #20839] which doesn't remove the NODELETE

     object when _dl_open_check throws an exception.  Move it after

     relocation to avoid leaving the NODELETE object mapped without

     relocation.  */

  _dl_open_check (new);

  /* If the file is not loaded now as a dependency, add the search

     list of the newly loaded object to the scope.  */

  bool any_tls = false;

  unsigned int first_static_tls = new->l_searchlist.r_nlist;

  for (unsigned int i = 0; i < new->l_searchlist.r_nlist; ++i)

    {

      struct link_map *imap = new->l_searchlist.r_list[i];

      int from_scope = 0;

      /* If the initializer has been called already, the object has

	 not been loaded here and now.  */

      if (imap->l_init_called && imap->l_type == lt_loaded)

	{

	  struct r_scope_elem **runp = imap->l_scope;

	  size_t cnt = 0;

	  while (*runp != NULL)

	    {

	      if (*runp == &new->l_searchlist)

		break;

	      ++cnt;

	      ++runp;

	    }

	  if (*runp != NULL)

	    /* Avoid duplicates.  */

	    continue;

	  if (__glibc_unlikely (cnt + 1 >= imap->l_scope_max))

	    {

	      /* The 'r_scope' array is too small.  Allocate a new one

		 dynamically.  */

	      size_t new_size;

	      struct r_scope_elem **newp;

#define SCOPE_ELEMS(imap) \

  (sizeof (imap->l_scope_mem) / sizeof (imap->l_scope_mem[0]))

	      if (imap->l_scope != imap->l_scope_mem

		  && imap->l_scope_max < SCOPE_ELEMS (imap))

		{

		  new_size = SCOPE_ELEMS (imap);

		  newp = imap->l_scope_mem;

		}

	      else

		{

		  new_size = imap->l_scope_max * 2;

		  newp = (struct r_scope_elem **)

		    malloc (new_size * sizeof (struct r_scope_elem *));

		  if (newp == NULL)

		    _dl_signal_error (ENOMEM, "dlopen", NULL,

				      N_("cannot create scope list"));

		}

	      memcpy (newp, imap->l_scope, cnt * sizeof (imap->l_scope[0]));

	      struct r_scope_elem **old = imap->l_scope;

	      imap->l_scope = newp;

	      if (old != imap->l_scope_mem)

		_dl_scope_free (old);

	      imap->l_scope_max = new_size;

	    }

	  /* First terminate the extended list.  Otherwise a thread

	     might use the new last element and then use the garbage

	     at offset IDX+1.  */

	  imap->l_scope[cnt + 1] = NULL;

	  atomic_write_barrier ();

	  imap->l_scope[cnt] = &new->l_searchlist;

	  /* Print only new scope information.  */

	  from_scope = cnt;

	}

      /* Only add TLS memory if this object is loaded now and

	 therefore is not yet initialized.  */

      else if (! imap->l_init_called

	       /* Only if the module defines thread local data.  */

	       && __builtin_expect (imap->l_tls_blocksize > 0, 0))

	{

	  /* Now that we know the object is loaded successfully add

	     modules containing TLS data to the slot info table.  We

	     might have to increase its size.  */

	  _dl_add_to_slotinfo (imap);

	  if (imap->l_need_tls_init

	      && first_static_tls == new->l_searchlist.r_nlist)

	    first_static_tls = i;

	  /* We have to bump the generation counter.  */

	  any_tls = true;

	}

      /* Print scope information.  */

      if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_SCOPES))

	_dl_show_scope (imap, from_scope);

    }

  /* Bump the generation number if necessary.  */

  if (any_tls && __builtin_expect (++GL(dl_tls_generation) == 0, 0))

    _dl_fatal_printf (N_("\

TLS generation counter wrapped!  Please report this."));

  /* We need a second pass for static tls data, because _dl_update_slotinfo

     must not be run while calls to _dl_add_to_slotinfo are still pending.  */

  for (unsigned int i = first_static_tls; i < new->l_searchlist.r_nlist; ++i)

    {

      struct link_map *imap = new->l_searchlist.r_list[i];

      if (imap->l_need_tls_init

	  && ! imap->l_init_called

	  && imap->l_tls_blocksize > 0)

	{

	  /* For static TLS we have to allocate the memory here and

	     now, but we can delay updating the DTV.  */

	  imap->l_need_tls_init = 0;

#ifdef SHARED

	  /* Update the slot information data for at least the

	     generation of the DSO we are allocating data for.  */

	  _dl_update_slotinfo (imap->l_tls_modid);

#endif

	  GL(dl_init_static_tls) (imap);

	  assert (imap->l_need_tls_init == 0);

	}

    }

  /* Notify the debugger all new objects have been relocated.  */

  if (relocation_in_progress)

    LIBC_PROBE (reloc_complete, 3, args->nsid, r, new);

#ifndef SHARED

  DL_STATIC_INIT (new);

#endif

  /* Run the initializer functions of new objects.  */

  _dl_init (new, args->argc, args->argv, args->env);

  /* Now we can make the new map available in the global scope.  */

  if (mode & RTLD_GLOBAL)

    /* Move the object in the global namespace.  */

    if (add_to_global (new) != 0)

      /* It failed.  */

      return;

#ifndef SHARED

  /* We must be the static _dl_open in libc.a.  A static program that

     has loaded a dynamic object now has competition.  */

  __libc_multiple_libcs = 1;

#endif

  /* Let the user know about the opencount.  */

  if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_FILES))

    _dl_debug_printf ("opening file=%s [%lu]; direct_opencount=%u\n\n",

		      new->l_name, new->l_ns, new->l_direct_opencount);

}

void *

_dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,

	  int argc, char *argv[], char *env[])

{

  if ((mode & RTLD_BINDING_MASK) == 0)

    /* One of the flags must be set.  */

    _dl_signal_error (EINVAL, file, NULL, N_("invalid mode for dlopen()"));

  /* Make sure we are alone.  */

  __rtld_lock_lock_recursive (GL(dl_load_lock));

  if (__glibc_unlikely (nsid == LM_ID_NEWLM))

    {

      /* Find a new namespace.  */

      for (nsid = 1; DL_NNS > 1 && nsid < GL(dl_nns); ++nsid)

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

	  break;

      if (__glibc_unlikely (nsid == DL_NNS))

	{

	  /* No more namespace available.  */

	  __rtld_lock_unlock_recursive (GL(dl_load_lock));

	  _dl_signal_error (EINVAL, file, NULL, N_("\

no more namespaces available for dlmopen()"));

	}

      else if (nsid == GL(dl_nns))

	{

	  __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);

	  ++GL(dl_nns);

	}

      _dl_debug_initialize (0, nsid)->r_state = RT_CONSISTENT;

    }

  /* Never allow loading a DSO in a namespace which is empty.  Such

     direct placements is only causing problems.  Also don't allow

     loading into a namespace used for auditing.  */

  else if (__glibc_unlikely (nsid != LM_ID_BASE && nsid != __LM_ID_CALLER)

	   && (__glibc_unlikely (nsid < 0 || nsid >= GL(dl_nns))

	       /* This prevents the [NSID] index expressions from being

		  evaluated, so the compiler won't think that we are

		  accessing an invalid index here in the !SHARED case where

		  DL_NNS is 1 and so any NSID != 0 is invalid.  */

	       || DL_NNS == 1

	       || GL(dl_ns)[nsid]._ns_nloaded == 0

	       || GL(dl_ns)[nsid]._ns_loaded->l_auditing))

    _dl_signal_error (EINVAL, file, NULL,

		      N_("invalid target namespace in dlmopen()"));

  struct dl_open_args args;

  args.file = file;

  args.mode = mode;

  args.caller_dlopen = caller_dlopen;

  args.map = NULL;

  args.nsid = nsid;

  args.argc = argc;

  args.argv = argv;

  args.env = env;

  struct dl_exception exception;

  int errcode = _dl_catch_exception (&exception, dl_open_worker, &args);

#if defined USE_LDCONFIG && !defined MAP_COPY

  /* We must unmap the cache file.  */

  _dl_unload_cache ();

#endif

  /* See if an error occurred during loading.  */

  if (__glibc_unlikely (exception.errstring != NULL))

    {

      /* Remove the object from memory.  It may be in an inconsistent

	 state if relocation failed, for example.  */

      if (args.map)

	{

	  /* Maybe some of the modules which were loaded use TLS.

	     Since it will be removed in the following _dl_close call

	     we have to mark the dtv array as having gaps to fill the

	     holes.  This is a pessimistic assumption which won't hurt

	     if not true.  There is no need to do this when we are

	     loading the auditing DSOs since TLS has not yet been set

	     up.  */

	  if ((mode & __RTLD_AUDIT) == 0)

	    GL(dl_tls_dtv_gaps) = true;

	  _dl_close_worker (args.map, true);

	}

      assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);

      /* Release the lock.  */

      __rtld_lock_unlock_recursive (GL(dl_load_lock));

      /* Reraise the error.  */

      _dl_signal_exception (errcode, &exception, NULL);

    }

  assert (_dl_debug_initialize (0, args.nsid)->r_state == RT_CONSISTENT);

  /* Release the lock.  */

  __rtld_lock_unlock_recursive (GL(dl_load_lock));

  return args.map;

}

void

_dl_show_scope (struct link_map *l, int from)

{

  _dl_debug_printf ("object=%s [%lu]\n",

		    DSO_FILENAME (l->l_name), l->l_ns);

  if (l->l_scope != NULL)

    for (int scope_cnt = from; l->l_scope[scope_cnt] != NULL; ++scope_cnt)

      {

	_dl_debug_printf (" scope %u:", scope_cnt);

	for (unsigned int cnt = 0; cnt < l->l_scope[scope_cnt]->r_nlist; ++cnt)

	  if (*l->l_scope[scope_cnt]->r_list[cnt]->l_name)

	    _dl_debug_printf_c (" %s",

				l->l_scope[scope_cnt]->r_list[cnt]->l_name);

	  else

	    _dl_debug_printf_c (" %s", RTLD_PROGNAME);

	_dl_debug_printf_c ("\n");

      }

  else

    _dl_debug_printf (" no scope\n");

  _dl_debug_printf ("\n");

}