diff options
Diffstat (limited to 'elf/dl-version.c')
| -rw-r--r-- | elf/dl-version.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/elf/dl-version.c b/elf/dl-version.c new file mode 100644 index 0000000000..4382a4c0ae --- /dev/null +++ b/elf/dl-version.c @@ -0,0 +1,337 @@ +/* Handle symbol and library versioning. + Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#include <elf.h> +#include <errno.h> +#include <link.h> +#include <stdlib.h> +#include <string.h> +#include <assert.h> + +#include "../stdio-common/_itoa.h" + + +/* Set in rtld.c at startup. */ +extern char **_dl_argv; + +#define VERSTAG(tag) (DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (tag)) + + +#define make_string(string, rest...) \ + ({ \ + const char *all[] = { string, ## rest }; \ + size_t len, cnt; \ + char *result, *cp; \ + \ + len = 1; \ + for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \ + len += strlen (all[cnt]); \ + \ + cp = result = alloca (len); \ + for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt) \ + cp = stpcpy (cp, all[cnt]); \ + \ + result; \ + }) + + +static inline struct link_map * +find_needed (struct link_map *map, const char *name) +{ + unsigned int n; + + for (n = 0; n < map->l_nsearchlist; ++n) + if (_dl_does_name_match_p (name, map->l_searchlist[n])) + return map->l_searchlist[n]; + + /* Should never happen. */ + return NULL; +} + + +static int +match_symbol (const char *name, ElfW(Word) hash, const char *string, + struct link_map *map, int verbose, int weak) +{ + const char *strtab = (const char *) (map->l_addr + + map->l_info[DT_STRTAB]->d_un.d_ptr); + ElfW(Addr) def_offset = map->l_info[VERSTAG (DT_VERDEF)]->d_un.d_ptr; + ElfW(Verdef) *def; + + if (def_offset == 0) + { + /* The file has no symbol versioning. I.e., the dependent + object was linked against another version of this file. We + only print a message if verbose output is requested. */ + if (verbose) + _dl_signal_error (0, map->l_name, make_string ("\ +no version information available (required by ", + name, ")")); + return 0; + } + + def = (ElfW(Verdef) *) (map->l_addr + def_offset); + while (1) + { + /* Currently the version number of the definition entry is 1. + Make sure all we see is this version. */ + if (def->vd_version != 1) + { + char buf[20]; + buf[sizeof (buf) - 1] = '\0'; + _dl_signal_error (0, map->l_name, + make_string ("unsupported version ", + _itoa_word (def->vd_version, + &buf[sizeof (buf) - 1], + 10, 0), + " of Verdef record")); + return 1; + } + + /* Compare the hash values. */ + if (hash == def->vd_hash) + { + ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux); + + /* To be safe, compare the string as well. */ + if (strcmp (string, strtab + aux->vda_name) == 0) + /* Bingo! */ + return 0; + } + + /* If no more definitions we failed to find what we want. */ + if (def->vd_next == 0) + break; + + /* Next definition. */ + def = (ElfW(Verdef) *) ((char *) def + def->vd_next); + } + + /* Symbol not found. If it was a weak reference it is not fatal. */ + if (weak) + { + if (verbose) + _dl_signal_error (0, map->l_name, + make_string ("weak version `", string, + "' not found (required by ", name, + ")")); + return 0; + } + + _dl_signal_error (0, map->l_name, + make_string ("version `", string, + "' not found (required by ", name, ")")); + return 1; +} + + +int +_dl_check_map_versions (struct link_map *map, int verbose) +{ + int result = 0; + const char *strtab = (const char *) (map->l_addr + + map->l_info[DT_STRTAB]->d_un.d_ptr); + /* Pointer to section with needed versions. */ + ElfW(Dyn) *dyn = map->l_info[VERSTAG (DT_VERNEED)]; + /* Pointer to dynamic section with definitions. */ + ElfW(Dyn) *def = map->l_info[VERSTAG (DT_VERDEF)]; + /* We need to find out which is the highest version index used + in a dependecy. */ + unsigned int ndx_high = 0; + + if (dyn != NULL) + { + /* This file requires special versions from its dependencies. */ + ElfW(Verneed) *ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); + + /* Currently the version number of the needed entry is 1. + Make sure all we see is this version. */ + if (ent->vn_version != 1) + { + char buf[20]; + buf[sizeof (buf) - 1] = '\0'; + _dl_signal_error (0, (*map->l_name ? map->l_name : _dl_argv[0]), + make_string ("unsupported version ", + _itoa_word (ent->vn_version, + &buf[sizeof (buf) - 1], + 10, 0), + " of Verneed record\n")); + return 1; + } + + while (1) + { + ElfW(Vernaux) *aux; + struct link_map *needed = find_needed (map, strtab + ent->vn_file); + + /* If NEEDED is NULL this means a dependency was not found + and no stub entry was created. This should never happen. */ + assert (needed != NULL); + + /* NEEDED is the map for the file we need. Now look for the + dependency symbols. */ + aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); + while (1) + { + /* Match the symbol. */ + result |= match_symbol ((*map->l_name + ? map->l_name : _dl_argv[0]), + aux->vna_hash, + strtab + aux->vna_name, + needed, verbose, + aux->vna_flags & VER_FLG_WEAK); + + /* Compare the version index. */ + if ((aux->vna_other & 0x7fff) > ndx_high) + ndx_high = aux->vna_other & 0x7fff; + + if (aux->vna_next == 0) + /* No more symbols. */ + break; + + /* Next symbol. */ + aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next); + } + + if (ent->vn_next == 0) + /* No more dependencies. */ + break; + + /* Next dependency. */ + ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); + } + } + + /* We also must store the names of the defined versions. Determine + the maximum index here as well. + + XXX We could avoid the loop by just taking the number of definitions + as an upper bound of new indeces. */ + if (def != NULL) + { + ElfW(Verdef) *ent; + ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr); + while (1) + { + if ((ent->vd_ndx & 0x7fff) > ndx_high) + ndx_high = ent->vd_ndx & 0x7fff; + + if (ent->vd_next == 0) + /* No more definitions. */ + break; + + ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); + } + } + + if (ndx_high > 0) + { + /* Now we are ready to build the array with the version names + which can be indexed by the version index in the VERSYM + section. */ + map->l_versions = (hash_name_pair*) malloc ((ndx_high + 1) + * sizeof (hash_name_pair)); + memset (map->l_versions, '\0', (ndx_high + 1) * sizeof (hash_name_pair)); + if (map->l_versions == NULL) + { + _dl_signal_error (ENOMEM, (*map->l_name ? map->l_name : _dl_argv[0]), + "cannot allocate version name table"); + result = 1; + } + else + { + /* Store the number of available symbols. */ + map->l_nversions = ndx_high + 1; + + if (dyn != NULL) + { + ElfW(Verneed) *ent; + ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr); + while (1) + { + ElfW(Vernaux) *aux; + aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux); + while (1) + { + ElfW(Half) ndx = aux->vna_other & 0x7fff; + map->l_versions[ndx].hash = aux->vna_hash; + map->l_versions[ndx].name = &strtab[aux->vna_name]; + + if (aux->vna_next == 0) + /* No more symbols. */ + break; + + /* Advance to next symbol. */ + aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next); + } + + if (ent->vn_next == 0) + /* No more dependencies. */ + break; + + /* Advance to next dependency. */ + ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next); + } + } + + /* And insert the defined versions. */ + if (def != NULL) + { + ElfW(Verdef) *ent; + ent = (ElfW(Verdef) *) (map->l_addr + def->d_un.d_ptr); + while (1) + { + ElfW(Verdaux) *aux; + aux = (ElfW(Verdaux) *) ((char *) ent + ent->vd_aux); + + if ((ent->vd_flags & VER_FLG_BASE) == 0) + { + /* The name of the base version should not be + available for matching a versioned symbol. */ + ElfW(Half) ndx = ent->vd_ndx & 0x7fff; + map->l_versions[ndx].hash = ent->vd_hash; + map->l_versions[ndx].name = &strtab[aux->vda_name]; + } + + if (ent->vd_next == 0) + /* No more definitions. */ + break; + + ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); + } + } + } + } + + return result; +} + + +int +_dl_check_all_versions (struct link_map *map, int verbose) +{ + struct link_map *l; + int result = 0; + + for (l = map; l != NULL; l = l->l_next) + result |= _dl_check_map_versions (l, verbose); + + return result; +} |