diff options
Diffstat (limited to 'REORG.TODO/elf/dl-version.c')
| -rw-r--r-- | REORG.TODO/elf/dl-version.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/REORG.TODO/elf/dl-version.c b/REORG.TODO/elf/dl-version.c new file mode 100644 index 0000000000..c00078e5e4 --- /dev/null +++ b/REORG.TODO/elf/dl-version.c @@ -0,0 +1,389 @@ +/* Handle symbol and library versioning. + Copyright (C) 1997-2017 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 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 <elf.h> +#include <errno.h> +#include <libintl.h> +#include <stdlib.h> +#include <string.h> +#include <ldsodefs.h> +#include <_itoa.h> + +#include <assert.h> + + +#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 * +__attribute ((always_inline)) +find_needed (const char *name, struct link_map *map) +{ + struct link_map *tmap; + unsigned int n; + + for (tmap = GL(dl_ns)[map->l_ns]._ns_loaded; tmap != NULL; + tmap = tmap->l_next) + if (_dl_name_match_p (name, tmap)) + return tmap; + + /* The required object is not in the global scope, look to see if it is + a dependency of the current object. */ + for (n = 0; n < map->l_searchlist.r_nlist; n++) + if (_dl_name_match_p (name, map->l_searchlist.r_list[n])) + return map->l_searchlist.r_list[n]; + + /* Should never happen. */ + return NULL; +} + + +static int +internal_function +match_symbol (const char *name, Lmid_t ns, ElfW(Word) hash, const char *string, + struct link_map *map, int verbose, int weak) +{ + const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + ElfW(Addr) def_offset; + ElfW(Verdef) *def; + /* Initialize to make the compiler happy. */ + const char *errstring = NULL; + int result = 0; + + /* Display information about what we are doing while debugging. */ + if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_VERSIONS)) + _dl_debug_printf ("\ +checking for version `%s' in file %s [%lu] required by file %s [%lu]\n", + string, DSO_FILENAME (map->l_name), + map->l_ns, name, ns); + + if (__glibc_unlikely (map->l_info[VERSYMIDX (DT_VERDEF)] == NULL)) + { + /* 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) + { + /* XXX We cannot translate the messages. */ + errstring = make_string ("\ +no version information available (required by ", name, ")"); + goto call_cerror; + } + return 0; + } + + def_offset = map->l_info[VERSYMIDX (DT_VERDEF)]->d_un.d_ptr; + assert (def_offset != 0); + + def = (ElfW(Verdef) *) ((char *) 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 (__builtin_expect (def->vd_version, 1) != 1) + { + char buf[20]; + buf[sizeof (buf) - 1] = '\0'; + /* XXX We cannot translate the message. */ + errstring = make_string ("unsupported version ", + _itoa (def->vd_version, + &buf[sizeof (buf) - 1], 10, 0), + " of Verdef record"); + result = 1; + goto call_cerror; + } + + /* 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 (__builtin_expect (strcmp (string, strtab + aux->vda_name), 0) + == 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 (__glibc_likely (weak)) + { + if (verbose) + { + /* XXX We cannot translate the message. */ + errstring = make_string ("weak version `", string, + "' not found (required by ", name, ")"); + goto call_cerror; + } + return 0; + } + + /* XXX We cannot translate the message. */ + errstring = make_string ("version `", string, "' not found (required by ", + name, ")"); + result = 1; + call_cerror: + _dl_signal_cerror (0, DSO_FILENAME (map->l_name), + N_("version lookup error"), errstring); + return result; +} + + +int +internal_function +_dl_check_map_versions (struct link_map *map, int verbose, int trace_mode) +{ + int result = 0; + const char *strtab; + /* Pointer to section with needed versions. */ + ElfW(Dyn) *dyn; + /* Pointer to dynamic section with definitions. */ + ElfW(Dyn) *def; + /* We need to find out which is the highest version index used + in a dependecy. */ + unsigned int ndx_high = 0; + /* Initialize to make the compiler happy. */ + const char *errstring = NULL; + int errval = 0; + + /* If we don't have a string table, we must be ok. */ + if (map->l_info[DT_STRTAB] == NULL) + return 0; + strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); + + dyn = map->l_info[VERSYMIDX (DT_VERNEED)]; + def = map->l_info[VERSYMIDX (DT_VERDEF)]; + + 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 (__builtin_expect (ent->vn_version, 1) != 1) + { + char buf[20]; + buf[sizeof (buf) - 1] = '\0'; + /* XXX We cannot translate the message. */ + errstring = make_string ("unsupported version ", + _itoa (ent->vn_version, + &buf[sizeof (buf) - 1], 10, 0), + " of Verneed record\n"); + call_error: + _dl_signal_error (errval, DSO_FILENAME (map->l_name), + NULL, errstring); + } + + while (1) + { + ElfW(Vernaux) *aux; + struct link_map *needed = find_needed (strtab + ent->vn_file, map); + + /* If NEEDED is NULL this means a dependency was not found + and no stub entry was created. This should never happen. */ + assert (needed != NULL); + + /* Make sure this is no stub we created because of a missing + dependency. */ + if (__builtin_expect (! trace_mode, 1) + || ! __builtin_expect (needed->l_faked, 0)) + { + /* 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 (DSO_FILENAME (map->l_name), + map->l_ns, aux->vna_hash, + strtab + aux->vna_name, + needed->l_real, verbose, + aux->vna_flags & VER_FLG_WEAK); + + /* Compare the version index. */ + if ((unsigned int) (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 ((unsigned int) (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 = (struct r_found_version *) + calloc (ndx_high + 1, sizeof (*map->l_versions)); + if (__glibc_unlikely (map->l_versions == NULL)) + { + errstring = N_("cannot allocate version reference table"); + errval = ENOMEM; + goto call_error; + } + + /* Store the number of available symbols. */ + map->l_nversions = ndx_high + 1; + + /* Compute the pointer to the version symbols. */ + map->l_versyms = (void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]); + + 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; + /* In trace mode, dependencies may be missing. */ + if (__glibc_likely (ndx < map->l_nversions)) + { + map->l_versions[ndx].hash = aux->vna_hash; + map->l_versions[ndx].hidden = aux->vna_other & 0x8000; + map->l_versions[ndx].name = &strtab[aux->vna_name]; + map->l_versions[ndx].filename = &strtab[ent->vn_file]; + } + + 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]; + map->l_versions[ndx].filename = NULL; + } + + if (ent->vd_next == 0) + /* No more definitions. */ + break; + + ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next); + } + } + } + + return result; +} + + +int +internal_function +_dl_check_all_versions (struct link_map *map, int verbose, int trace_mode) +{ + struct link_map *l; + int result = 0; + + for (l = map; l != NULL; l = l->l_next) + result |= (! l->l_faked + && _dl_check_map_versions (l, verbose, trace_mode)); + + return result; +} |