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89baed0b93
This reverts commit 6f85dbf102
.
Once this change hits the release branches, it will require relinking
of all statically linked applications before static dlopen works
again, for the majority of updates on release branches: The NEWS file
is regularly updated with bug references, so the __libc_early_init
suffix changes, and static dlopen cannot find the function anymore.
While this ABI check is still technically correct (we do require
rebuilding & relinking after glibc updates to keep static dlopen
working), it is too drastic for stable release branches.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
402 lines
12 KiB
C
402 lines
12 KiB
C
/* Handle symbol and library versioning.
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Copyright (C) 1997-2022 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 <elf.h>
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#include <errno.h>
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#include <libintl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ldsodefs.h>
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#include <_itoa.h>
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#include <assert.h>
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static inline struct link_map *
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__attribute ((always_inline))
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find_needed (const char *name, struct link_map *map)
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{
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struct link_map *tmap;
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unsigned int n;
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for (tmap = GL(dl_ns)[map->l_ns]._ns_loaded; tmap != NULL;
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tmap = tmap->l_next)
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if (_dl_name_match_p (name, tmap))
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return tmap;
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/* The required object is not in the global scope, look to see if it is
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a dependency of the current object. */
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for (n = 0; n < map->l_searchlist.r_nlist; n++)
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if (_dl_name_match_p (name, map->l_searchlist.r_list[n]))
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return map->l_searchlist.r_list[n];
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/* Should never happen. */
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return NULL;
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}
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static int
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match_symbol (const char *name, Lmid_t ns, ElfW(Word) hash, const char *string,
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struct link_map *map, int verbose, int weak)
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{
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const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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ElfW(Addr) def_offset;
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ElfW(Verdef) *def;
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/* Initialize to make the compiler happy. */
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int result = 0;
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struct dl_exception exception;
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/* Display information about what we are doing while debugging. */
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if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_VERSIONS))
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_dl_debug_printf ("\
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checking for version `%s' in file %s [%lu] required by file %s [%lu]\n",
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string, DSO_FILENAME (map->l_name),
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map->l_ns, name, ns);
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if (__glibc_unlikely (map->l_info[VERSYMIDX (DT_VERDEF)] == NULL))
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{
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/* The file has no symbol versioning. I.e., the dependent
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object was linked against another version of this file. We
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only print a message if verbose output is requested. */
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if (verbose)
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{
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/* XXX We cannot translate the messages. */
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_dl_exception_create_format
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(&exception, DSO_FILENAME (map->l_name),
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"no version information available (required by %s)", name);
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goto call_cerror;
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}
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return 0;
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}
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def_offset = map->l_info[VERSYMIDX (DT_VERDEF)]->d_un.d_ptr;
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assert (def_offset != 0);
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def = (ElfW(Verdef) *) ((char *) map->l_addr + def_offset);
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while (1)
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{
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/* Currently the version number of the definition entry is 1.
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Make sure all we see is this version. */
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if (__builtin_expect (def->vd_version, 1) != 1)
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{
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char buf[20];
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buf[sizeof (buf) - 1] = '\0';
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/* XXX We cannot translate the message. */
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_dl_exception_create_format
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(&exception, DSO_FILENAME (map->l_name),
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"unsupported version %s of Verdef record",
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_itoa (def->vd_version, &buf[sizeof (buf) - 1], 10, 0));
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result = 1;
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goto call_cerror;
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}
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/* Compare the hash values. */
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if (hash == def->vd_hash)
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{
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ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
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/* To be safe, compare the string as well. */
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if (__builtin_expect (strcmp (string, strtab + aux->vda_name), 0)
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== 0)
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/* Bingo! */
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return 0;
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}
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/* If no more definitions we failed to find what we want. */
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if (def->vd_next == 0)
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break;
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/* Next definition. */
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def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
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}
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/* Symbol not found. If it was a weak reference it is not fatal. */
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if (__glibc_likely (weak))
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{
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if (verbose)
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{
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/* XXX We cannot translate the message. */
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_dl_exception_create_format
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(&exception, DSO_FILENAME (map->l_name),
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"weak version `%s' not found (required by %s)", string, name);
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goto call_cerror;
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}
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return 0;
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}
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/* XXX We cannot translate the message. */
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_dl_exception_create_format
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(&exception, DSO_FILENAME (map->l_name),
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"version `%s' not found (required by %s)", string, name);
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result = 1;
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call_cerror:
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_dl_signal_cexception (0, &exception, N_("version lookup error"));
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_dl_exception_free (&exception);
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return result;
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}
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int
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_dl_check_map_versions (struct link_map *map, int verbose, int trace_mode)
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{
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int result = 0;
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const char *strtab;
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/* Pointer to section with needed versions. */
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ElfW(Dyn) *dyn;
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/* Pointer to dynamic section with definitions. */
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ElfW(Dyn) *def;
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/* We need to find out which is the highest version index used
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in a dependecy. */
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unsigned int ndx_high = 0;
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struct dl_exception exception;
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/* Initialize to make the compiler happy. */
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int errval = 0;
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/* If we don't have a string table, we must be ok. */
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if (map->l_info[DT_STRTAB] == NULL)
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return 0;
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strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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dyn = map->l_info[VERSYMIDX (DT_VERNEED)];
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def = map->l_info[VERSYMIDX (DT_VERDEF)];
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if (dyn != NULL)
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{
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/* This file requires special versions from its dependencies. */
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ElfW(Verneed) *ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
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/* Currently the version number of the needed entry is 1.
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Make sure all we see is this version. */
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if (__builtin_expect (ent->vn_version, 1) != 1)
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{
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char buf[20];
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buf[sizeof (buf) - 1] = '\0';
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/* XXX We cannot translate the message. */
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_dl_exception_create_format
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(&exception, DSO_FILENAME (map->l_name),
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"unsupported version %s of Verneed record",
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_itoa (ent->vn_version, &buf[sizeof (buf) - 1], 10, 0));
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call_error:
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_dl_signal_exception (errval, &exception, NULL);
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}
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while (1)
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{
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ElfW(Vernaux) *aux;
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struct link_map *needed = find_needed (strtab + ent->vn_file, map);
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/* If NEEDED is NULL this means a dependency was not found
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and no stub entry was created. This should never happen. */
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assert (needed != NULL);
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/* Make sure this is no stub we created because of a missing
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dependency. */
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if (__builtin_expect (! trace_mode, 1)
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|| ! __builtin_expect (needed->l_faked, 0))
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{
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/* NEEDED is the map for the file we need. Now look for the
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dependency symbols. */
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aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
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while (1)
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{
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/* Match the symbol. */
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const char *string = strtab + aux->vna_name;
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result |= match_symbol (DSO_FILENAME (map->l_name),
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map->l_ns, aux->vna_hash,
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string, needed->l_real, verbose,
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aux->vna_flags & VER_FLG_WEAK);
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/* 0xfd0e42: _dl_elf_hash ("GLIBC_ABI_DT_RELR"). */
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if (aux->vna_hash == 0xfd0e42
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&& __glibc_likely (strcmp (string,
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"GLIBC_ABI_DT_RELR")
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== 0))
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map->l_dt_relr_ref = 1;
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/* Compare the version index. */
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if ((unsigned int) (aux->vna_other & 0x7fff) > ndx_high)
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ndx_high = aux->vna_other & 0x7fff;
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if (aux->vna_next == 0)
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/* No more symbols. */
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break;
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/* Next symbol. */
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aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
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}
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}
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if (ent->vn_next == 0)
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/* No more dependencies. */
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break;
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/* Next dependency. */
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ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
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}
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}
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/* We also must store the names of the defined versions. Determine
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the maximum index here as well.
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XXX We could avoid the loop by just taking the number of definitions
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as an upper bound of new indices. */
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if (def != NULL)
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{
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ElfW(Verdef) *ent;
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ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr);
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while (1)
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{
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if ((unsigned int) (ent->vd_ndx & 0x7fff) > ndx_high)
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ndx_high = ent->vd_ndx & 0x7fff;
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if (ent->vd_next == 0)
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/* No more definitions. */
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break;
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ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
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}
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}
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if (ndx_high > 0)
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{
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/* Now we are ready to build the array with the version names
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which can be indexed by the version index in the VERSYM
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section. */
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map->l_versions = (struct r_found_version *)
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calloc (ndx_high + 1, sizeof (*map->l_versions));
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if (__glibc_unlikely (map->l_versions == NULL))
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{
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_dl_exception_create
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(&exception, DSO_FILENAME (map->l_name),
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N_("cannot allocate version reference table"));
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errval = ENOMEM;
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goto call_error;
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}
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/* Store the number of available symbols. */
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map->l_nversions = ndx_high + 1;
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/* Compute the pointer to the version symbols. */
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map->l_versyms = (void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
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if (dyn != NULL)
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{
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ElfW(Verneed) *ent;
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ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
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while (1)
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{
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ElfW(Vernaux) *aux;
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aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
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while (1)
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{
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ElfW(Half) ndx = aux->vna_other & 0x7fff;
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/* In trace mode, dependencies may be missing. */
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if (__glibc_likely (ndx < map->l_nversions))
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{
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map->l_versions[ndx].hash = aux->vna_hash;
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map->l_versions[ndx].hidden = aux->vna_other & 0x8000;
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map->l_versions[ndx].name = &strtab[aux->vna_name];
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map->l_versions[ndx].filename = &strtab[ent->vn_file];
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}
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if (aux->vna_next == 0)
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/* No more symbols. */
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break;
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/* Advance to next symbol. */
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aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
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}
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if (ent->vn_next == 0)
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/* No more dependencies. */
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break;
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/* Advance to next dependency. */
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ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
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}
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}
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/* And insert the defined versions. */
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if (def != NULL)
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{
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ElfW(Verdef) *ent;
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ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr);
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while (1)
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{
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ElfW(Verdaux) *aux;
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aux = (ElfW(Verdaux) *) ((char *) ent + ent->vd_aux);
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if ((ent->vd_flags & VER_FLG_BASE) == 0)
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{
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/* The name of the base version should not be
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available for matching a versioned symbol. */
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ElfW(Half) ndx = ent->vd_ndx & 0x7fff;
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map->l_versions[ndx].hash = ent->vd_hash;
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map->l_versions[ndx].name = &strtab[aux->vda_name];
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map->l_versions[ndx].filename = NULL;
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}
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if (ent->vd_next == 0)
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/* No more definitions. */
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break;
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ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
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}
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}
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}
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/* When there is a DT_VERNEED entry with libc.so on DT_NEEDED, issue
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an error if there is a DT_RELR entry without GLIBC_ABI_DT_RELR
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dependency. */
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if (dyn != NULL
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&& map->l_info[DT_NEEDED] != NULL
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&& map->l_info[DT_RELR] != NULL
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&& __glibc_unlikely (!map->l_dt_relr_ref))
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{
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const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
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const ElfW(Dyn) *d;
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for (d = map->l_ld; d->d_tag != DT_NULL; ++d)
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if (d->d_tag == DT_NEEDED)
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{
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const char *name = strtab + d->d_un.d_val;
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if (strncmp (name, "libc.so.", 8) == 0)
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{
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_dl_exception_create
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(&exception, DSO_FILENAME (map->l_name),
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N_("DT_RELR without GLIBC_ABI_DT_RELR dependency"));
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goto call_error;
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}
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}
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}
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return result;
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}
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int
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_dl_check_all_versions (struct link_map *map, int verbose, int trace_mode)
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{
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struct link_map *l;
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int result = 0;
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for (l = map; l != NULL; l = l->l_next)
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result |= (! l->l_faked
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&& _dl_check_map_versions (l, verbose, trace_mode));
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return result;
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}
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