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7b5bfe7783
If we try to run constructors before relocation, this is always a dynamic linker bug. An assert is easier to notice than a call via an invalid function pointer (which may not even produce a valid call stack). Reviewed-by: Carlos O'Donell <carlos@redhat.com>
128 lines
4.3 KiB
C
128 lines
4.3 KiB
C
/* Run initializers for newly loaded objects.
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Copyright (C) 1995-2020 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <assert.h>
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#include <stddef.h>
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#include <ldsodefs.h>
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#include <elf-initfini.h>
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/* Type of the initializer. */
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typedef void (*init_t) (int, char **, char **);
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static void
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call_init (struct link_map *l, int argc, char **argv, char **env)
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{
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/* If the object has not been relocated, this is a bug. The
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function pointers are invalid in this case. (Executables do not
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need relocation, and neither do proxy objects.) */
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assert (l->l_real->l_relocated || l->l_real->l_type == lt_executable);
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if (l->l_init_called)
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/* This object is all done. */
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return;
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/* Avoid handling this constructor again in case we have a circular
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dependency. */
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l->l_init_called = 1;
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/* Check for object which constructors we do not run here. */
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if (__builtin_expect (l->l_name[0], 'a') == '\0'
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&& l->l_type == lt_executable)
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return;
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/* Print a debug message if wanted. */
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if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
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_dl_debug_printf ("\ncalling init: %s\n\n",
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DSO_FILENAME (l->l_name));
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/* Now run the local constructors. There are two forms of them:
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- the one named by DT_INIT
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- the others in the DT_INIT_ARRAY.
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*/
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if (ELF_INITFINI && l->l_info[DT_INIT] != NULL)
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DL_CALL_DT_INIT(l, l->l_addr + l->l_info[DT_INIT]->d_un.d_ptr, argc, argv, env);
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/* Next see whether there is an array with initialization functions. */
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ElfW(Dyn) *init_array = l->l_info[DT_INIT_ARRAY];
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if (init_array != NULL)
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{
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unsigned int j;
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unsigned int jm;
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ElfW(Addr) *addrs;
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jm = l->l_info[DT_INIT_ARRAYSZ]->d_un.d_val / sizeof (ElfW(Addr));
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addrs = (ElfW(Addr) *) (init_array->d_un.d_ptr + l->l_addr);
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for (j = 0; j < jm; ++j)
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((init_t) addrs[j]) (argc, argv, env);
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}
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}
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void
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_dl_init (struct link_map *main_map, int argc, char **argv, char **env)
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{
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ElfW(Dyn) *preinit_array = main_map->l_info[DT_PREINIT_ARRAY];
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ElfW(Dyn) *preinit_array_size = main_map->l_info[DT_PREINIT_ARRAYSZ];
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unsigned int i;
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if (__glibc_unlikely (GL(dl_initfirst) != NULL))
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{
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call_init (GL(dl_initfirst), argc, argv, env);
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GL(dl_initfirst) = NULL;
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}
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/* Don't do anything if there is no preinit array. */
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if (__builtin_expect (preinit_array != NULL, 0)
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&& preinit_array_size != NULL
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&& (i = preinit_array_size->d_un.d_val / sizeof (ElfW(Addr))) > 0)
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{
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ElfW(Addr) *addrs;
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unsigned int cnt;
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if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS))
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_dl_debug_printf ("\ncalling preinit: %s\n\n",
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DSO_FILENAME (main_map->l_name));
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addrs = (ElfW(Addr) *) (preinit_array->d_un.d_ptr + main_map->l_addr);
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for (cnt = 0; cnt < i; ++cnt)
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((init_t) addrs[cnt]) (argc, argv, env);
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}
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/* Stupid users forced the ELF specification to be changed. It now
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says that the dynamic loader is responsible for determining the
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order in which the constructors have to run. The constructors
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for all dependencies of an object must run before the constructor
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for the object itself. Circular dependencies are left unspecified.
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This is highly questionable since it puts the burden on the dynamic
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loader which has to find the dependencies at runtime instead of
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letting the user do it right. Stupidity rules! */
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i = main_map->l_searchlist.r_nlist;
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while (i-- > 0)
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call_init (main_map->l_initfini[i], argc, argv, env);
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#ifndef HAVE_INLINED_SYSCALLS
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/* Finished starting up. */
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_dl_starting_up = 0;
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#endif
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}
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