diff options
Diffstat (limited to 'REORG.TODO/elf/dl-deps.c')
| -rw-r--r-- | REORG.TODO/elf/dl-deps.c | 688 |
1 files changed, 688 insertions, 0 deletions
diff --git a/REORG.TODO/elf/dl-deps.c b/REORG.TODO/elf/dl-deps.c new file mode 100644 index 0000000000..1b8bac6593 --- /dev/null +++ b/REORG.TODO/elf/dl-deps.c @@ -0,0 +1,688 @@ +/* Load the dependencies of a mapped object. + Copyright (C) 1996-2017 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 <atomic.h> +#include <assert.h> +#include <dlfcn.h> +#include <errno.h> +#include <libintl.h> +#include <stddef.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/param.h> +#include <ldsodefs.h> + +#include <dl-dst.h> + +/* Whether an shared object references one or more auxiliary objects + is signaled by the AUXTAG entry in l_info. */ +#define AUXTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \ + + DT_EXTRATAGIDX (DT_AUXILIARY)) +/* Whether an shared object references one or more auxiliary objects + is signaled by the AUXTAG entry in l_info. */ +#define FILTERTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \ + + DT_EXTRATAGIDX (DT_FILTER)) + + +/* When loading auxiliary objects we must ignore errors. It's ok if + an object is missing. */ +struct openaux_args + { + /* The arguments to openaux. */ + struct link_map *map; + int trace_mode; + int open_mode; + const char *strtab; + const char *name; + + /* The return value of openaux. */ + struct link_map *aux; + }; + +static void +openaux (void *a) +{ + struct openaux_args *args = (struct openaux_args *) a; + + args->aux = _dl_map_object (args->map, args->name, + (args->map->l_type == lt_executable + ? lt_library : args->map->l_type), + args->trace_mode, args->open_mode, + args->map->l_ns); +} + +static ptrdiff_t +internal_function +_dl_build_local_scope (struct link_map **list, struct link_map *map) +{ + struct link_map **p = list; + struct link_map **q; + + *p++ = map; + map->l_reserved = 1; + if (map->l_initfini) + for (q = map->l_initfini + 1; *q; ++q) + if (! (*q)->l_reserved) + p += _dl_build_local_scope (p, *q); + return p - list; +} + + +/* We use a very special kind of list to track the path + through the list of loaded shared objects. We have to + produce a flat list with unique members of all involved objects. +*/ +struct list + { + int done; /* Nonzero if this map was processed. */ + struct link_map *map; /* The data. */ + struct list *next; /* Elements for normal list. */ + }; + + +/* Macro to expand DST. It is an macro since we use `alloca'. */ +#define expand_dst(l, str, fatal) \ + ({ \ + const char *__str = (str); \ + const char *__result = __str; \ + size_t __dst_cnt = DL_DST_COUNT (__str, 0); \ + \ + if (__dst_cnt != 0) \ + { \ + char *__newp; \ + \ + /* DST must not appear in SUID/SGID programs. */ \ + if (__libc_enable_secure) \ + _dl_signal_error (0, __str, NULL, N_("\ +DST not allowed in SUID/SGID programs")); \ + \ + __newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \ + __dst_cnt)); \ + \ + __result = _dl_dst_substitute (l, __str, __newp, 0); \ + \ + if (*__result == '\0') \ + { \ + /* The replacement for the DST is not known. We can't \ + processed. */ \ + if (fatal) \ + _dl_signal_error (0, __str, NULL, N_("\ +empty dynamic string token substitution")); \ + else \ + { \ + /* This is for DT_AUXILIARY. */ \ + if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS)) \ + _dl_debug_printf (N_("\ +cannot load auxiliary `%s' because of empty dynamic string token " \ + "substitution\n"), __str); \ + continue; \ + } \ + } \ + } \ + \ + __result; }) + +static void +preload (struct list *known, unsigned int *nlist, struct link_map *map) +{ + known[*nlist].done = 0; + known[*nlist].map = map; + known[*nlist].next = &known[*nlist + 1]; + + ++*nlist; + /* We use `l_reserved' as a mark bit to detect objects we have + already put in the search list and avoid adding duplicate + elements later in the list. */ + map->l_reserved = 1; +} + +void +internal_function +_dl_map_object_deps (struct link_map *map, + struct link_map **preloads, unsigned int npreloads, + int trace_mode, int open_mode) +{ + struct list *known = __alloca (sizeof *known * (1 + npreloads + 1)); + struct list *runp, *tail; + unsigned int nlist, i; + /* Object name. */ + const char *name; + int errno_saved; + int errno_reason; + const char *errstring; + const char *objname; + + /* No loaded object so far. */ + nlist = 0; + + /* First load MAP itself. */ + preload (known, &nlist, map); + + /* Add the preloaded items after MAP but before any of its dependencies. */ + for (i = 0; i < npreloads; ++i) + preload (known, &nlist, preloads[i]); + + /* Terminate the lists. */ + known[nlist - 1].next = NULL; + + /* Pointer to last unique object. */ + tail = &known[nlist - 1]; + + /* No alloca'd space yet. */ + struct link_map **needed_space = NULL; + size_t needed_space_bytes = 0; + + /* Process each element of the search list, loading each of its + auxiliary objects and immediate dependencies. Auxiliary objects + will be added in the list before the object itself and + dependencies will be appended to the list as we step through it. + This produces a flat, ordered list that represents a + breadth-first search of the dependency tree. + + The whole process is complicated by the fact that we better + should use alloca for the temporary list elements. But using + alloca means we cannot use recursive function calls. */ + errno_saved = errno; + errno_reason = 0; + errstring = NULL; + errno = 0; + name = NULL; + for (runp = known; runp; ) + { + struct link_map *l = runp->map; + struct link_map **needed = NULL; + unsigned int nneeded = 0; + + /* Unless otherwise stated, this object is handled. */ + runp->done = 1; + + /* Allocate a temporary record to contain the references to the + dependencies of this object. */ + if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL + && l != map && l->l_ldnum > 0) + { + size_t new_size = l->l_ldnum * sizeof (struct link_map *); + + if (new_size > needed_space_bytes) + needed_space + = extend_alloca (needed_space, needed_space_bytes, new_size); + + needed = needed_space; + } + + if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG]) + { + const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]); + struct openaux_args args; + struct list *orig; + const ElfW(Dyn) *d; + + args.strtab = strtab; + args.map = l; + args.trace_mode = trace_mode; + args.open_mode = open_mode; + orig = runp; + + for (d = l->l_ld; d->d_tag != DT_NULL; ++d) + if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED) + { + /* Map in the needed object. */ + struct link_map *dep; + + /* Recognize DSTs. */ + name = expand_dst (l, strtab + d->d_un.d_val, 0); + /* Store the tag in the argument structure. */ + args.name = name; + + bool malloced; + int err = _dl_catch_error (&objname, &errstring, &malloced, + openaux, &args); + if (__glibc_unlikely (errstring != NULL)) + { + char *new_errstring = strdupa (errstring); + objname = strdupa (objname); + if (malloced) + free ((char *) errstring); + errstring = new_errstring; + + if (err) + errno_reason = err; + else + errno_reason = -1; + goto out; + } + else + dep = args.aux; + + if (! dep->l_reserved) + { + /* Allocate new entry. */ + struct list *newp; + + newp = alloca (sizeof (struct list)); + + /* Append DEP to the list. */ + newp->map = dep; + newp->done = 0; + newp->next = NULL; + tail->next = newp; + tail = newp; + ++nlist; + /* Set the mark bit that says it's already in the list. */ + dep->l_reserved = 1; + } + + /* Remember this dependency. */ + if (needed != NULL) + needed[nneeded++] = dep; + } + else if (d->d_tag == DT_AUXILIARY || d->d_tag == DT_FILTER) + { + struct list *newp; + + /* Recognize DSTs. */ + name = expand_dst (l, strtab + d->d_un.d_val, + d->d_tag == DT_AUXILIARY); + /* Store the tag in the argument structure. */ + args.name = name; + + /* Say that we are about to load an auxiliary library. */ + if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_LIBS, + 0)) + _dl_debug_printf ("load auxiliary object=%s" + " requested by file=%s\n", + name, + DSO_FILENAME (l->l_name)); + + /* We must be prepared that the addressed shared + object is not available. For filter objects the dependency + must be available. */ + bool malloced; + int err = _dl_catch_error (&objname, &errstring, &malloced, + openaux, &args); + + if (__glibc_unlikely (errstring != NULL)) + { + if (d->d_tag == DT_AUXILIARY) + { + /* We are not interested in the error message. */ + assert (errstring != NULL); + if (malloced) + free ((char *) errstring); + + /* Simply ignore this error and continue the work. */ + continue; + } + else + { + + char *new_errstring = strdupa (errstring); + objname = strdupa (objname); + if (malloced) + free ((char *) errstring); + errstring = new_errstring; + + if (err) + errno_reason = err; + else + errno_reason = -1; + goto out; + } + } + + /* The auxiliary object is actually available. + Incorporate the map in all the lists. */ + + /* Allocate new entry. This always has to be done. */ + newp = alloca (sizeof (struct list)); + + /* We want to insert the new map before the current one, + but we have no back links. So we copy the contents of + the current entry over. Note that ORIG and NEWP now + have switched their meanings. */ + memcpy (newp, orig, sizeof (*newp)); + + /* Initialize new entry. */ + orig->done = 0; + orig->map = args.aux; + + /* Remember this dependency. */ + if (needed != NULL) + needed[nneeded++] = args.aux; + + /* We must handle two situations here: the map is new, + so we must add it in all three lists. If the map + is already known, we have two further possibilities: + - if the object is before the current map in the + search list, we do nothing. It is already found + early + - if the object is after the current one, we must + move it just before the current map to make sure + the symbols are found early enough + */ + if (args.aux->l_reserved) + { + /* The object is already somewhere in the list. + Locate it first. */ + struct list *late; + + /* This object is already in the search list we + are building. Don't add a duplicate pointer. + Just added by _dl_map_object. */ + for (late = newp; late->next != NULL; late = late->next) + if (late->next->map == args.aux) + break; + + if (late->next != NULL) + { + /* The object is somewhere behind the current + position in the search path. We have to + move it to this earlier position. */ + orig->next = newp; + + /* Now remove the later entry from the list + and adjust the tail pointer. */ + if (tail == late->next) + tail = late; + late->next = late->next->next; + + /* We must move the object earlier in the chain. */ + if (args.aux->l_prev != NULL) + args.aux->l_prev->l_next = args.aux->l_next; + if (args.aux->l_next != NULL) + args.aux->l_next->l_prev = args.aux->l_prev; + + args.aux->l_prev = newp->map->l_prev; + newp->map->l_prev = args.aux; + if (args.aux->l_prev != NULL) + args.aux->l_prev->l_next = args.aux; + args.aux->l_next = newp->map; + } + else + { + /* The object must be somewhere earlier in the + list. Undo to the current list element what + we did above. */ + memcpy (orig, newp, sizeof (*newp)); + continue; + } + } + else + { + /* This is easy. We just add the symbol right here. */ + orig->next = newp; + ++nlist; + /* Set the mark bit that says it's already in the list. */ + args.aux->l_reserved = 1; + + /* The only problem is that in the double linked + list of all objects we don't have this new + object at the correct place. Correct this here. */ + if (args.aux->l_prev) + args.aux->l_prev->l_next = args.aux->l_next; + if (args.aux->l_next) + args.aux->l_next->l_prev = args.aux->l_prev; + + args.aux->l_prev = newp->map->l_prev; + newp->map->l_prev = args.aux; + if (args.aux->l_prev != NULL) + args.aux->l_prev->l_next = args.aux; + args.aux->l_next = newp->map; + } + + /* Move the tail pointer if necessary. */ + if (orig == tail) + tail = newp; + + /* Move on the insert point. */ + orig = newp; + } + } + + /* Terminate the list of dependencies and store the array address. */ + if (needed != NULL) + { + needed[nneeded++] = NULL; + + struct link_map **l_initfini = (struct link_map **) + malloc ((2 * nneeded + 1) * sizeof needed[0]); + if (l_initfini == NULL) + _dl_signal_error (ENOMEM, map->l_name, NULL, + N_("cannot allocate dependency list")); + l_initfini[0] = l; + memcpy (&l_initfini[1], needed, nneeded * sizeof needed[0]); + memcpy (&l_initfini[nneeded + 1], l_initfini, + nneeded * sizeof needed[0]); + atomic_write_barrier (); + l->l_initfini = l_initfini; + l->l_free_initfini = 1; + } + + /* If we have no auxiliary objects just go on to the next map. */ + if (runp->done) + do + runp = runp->next; + while (runp != NULL && runp->done); + } + + out: + if (errno == 0 && errno_saved != 0) + __set_errno (errno_saved); + + struct link_map **old_l_initfini = NULL; + if (map->l_initfini != NULL && map->l_type == lt_loaded) + { + /* This object was previously loaded as a dependency and we have + a separate l_initfini list. We don't need it anymore. */ + assert (map->l_searchlist.r_list == NULL); + old_l_initfini = map->l_initfini; + } + + /* Store the search list we built in the object. It will be used for + searches in the scope of this object. */ + struct link_map **l_initfini = + (struct link_map **) malloc ((2 * nlist + 1) + * sizeof (struct link_map *)); + if (l_initfini == NULL) + _dl_signal_error (ENOMEM, map->l_name, NULL, + N_("cannot allocate symbol search list")); + + + map->l_searchlist.r_list = &l_initfini[nlist + 1]; + map->l_searchlist.r_nlist = nlist; + + for (nlist = 0, runp = known; runp; runp = runp->next) + { + if (__builtin_expect (trace_mode, 0) && runp->map->l_faked) + /* This can happen when we trace the loading. */ + --map->l_searchlist.r_nlist; + else + map->l_searchlist.r_list[nlist++] = runp->map; + + /* Now clear all the mark bits we set in the objects on the search list + to avoid duplicates, so the next call starts fresh. */ + runp->map->l_reserved = 0; + } + + if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_PRELINK, 0) != 0 + && map == GL(dl_ns)[LM_ID_BASE]._ns_loaded) + { + /* If we are to compute conflicts, we have to build local scope + for each library, not just the ultimate loader. */ + for (i = 0; i < nlist; ++i) + { + struct link_map *l = map->l_searchlist.r_list[i]; + unsigned int j, cnt; + + /* The local scope has been already computed. */ + if (l == map + || (l->l_local_scope[0] + && l->l_local_scope[0]->r_nlist) != 0) + continue; + + if (l->l_info[AUXTAG] || l->l_info[FILTERTAG]) + { + /* As current DT_AUXILIARY/DT_FILTER implementation needs to be + rewritten, no need to bother with prelinking the old + implementation. */ + _dl_signal_error (EINVAL, l->l_name, NULL, N_("\ +Filters not supported with LD_TRACE_PRELINKING")); + } + + cnt = _dl_build_local_scope (l_initfini, l); + assert (cnt <= nlist); + for (j = 0; j < cnt; j++) + { + l_initfini[j]->l_reserved = 0; + if (j && __builtin_expect (l_initfini[j]->l_info[DT_SYMBOLIC] + != NULL, 0)) + l->l_symbolic_in_local_scope = true; + } + + l->l_local_scope[0] = + (struct r_scope_elem *) malloc (sizeof (struct r_scope_elem) + + (cnt + * sizeof (struct link_map *))); + if (l->l_local_scope[0] == NULL) + _dl_signal_error (ENOMEM, map->l_name, NULL, + N_("cannot allocate symbol search list")); + l->l_local_scope[0]->r_nlist = cnt; + l->l_local_scope[0]->r_list = + (struct link_map **) (l->l_local_scope[0] + 1); + memcpy (l->l_local_scope[0]->r_list, l_initfini, + cnt * sizeof (struct link_map *)); + } + } + + /* Maybe we can remove some relocation dependencies now. */ + assert (map->l_searchlist.r_list[0] == map); + struct link_map_reldeps *l_reldeps = NULL; + if (map->l_reldeps != NULL) + { + for (i = 1; i < nlist; ++i) + map->l_searchlist.r_list[i]->l_reserved = 1; + + struct link_map **list = &map->l_reldeps->list[0]; + for (i = 0; i < map->l_reldeps->act; ++i) + if (list[i]->l_reserved) + { + /* Need to allocate new array of relocation dependencies. */ + l_reldeps = malloc (sizeof (*l_reldeps) + + map->l_reldepsmax + * sizeof (struct link_map *)); + if (l_reldeps == NULL) + /* Bad luck, keep the reldeps duplicated between + map->l_reldeps->list and map->l_initfini lists. */ + ; + else + { + unsigned int j = i; + memcpy (&l_reldeps->list[0], &list[0], + i * sizeof (struct link_map *)); + for (i = i + 1; i < map->l_reldeps->act; ++i) + if (!list[i]->l_reserved) + l_reldeps->list[j++] = list[i]; + l_reldeps->act = j; + } + } + + for (i = 1; i < nlist; ++i) + map->l_searchlist.r_list[i]->l_reserved = 0; + } + + /* Sort the initializer list to take dependencies into account. The binary + itself will always be initialize last. */ + memcpy (l_initfini, map->l_searchlist.r_list, + nlist * sizeof (struct link_map *)); + if (__glibc_likely (nlist > 1)) + { + /* We can skip looking for the binary itself which is at the front + of the search list. */ + i = 1; + uint16_t seen[nlist]; + memset (seen, 0, nlist * sizeof (seen[0])); + while (1) + { + /* Keep track of which object we looked at this round. */ + ++seen[i]; + struct link_map *thisp = l_initfini[i]; + + /* Find the last object in the list for which the current one is + a dependency and move the current object behind the object + with the dependency. */ + unsigned int k = nlist - 1; + while (k > i) + { + struct link_map **runp = l_initfini[k]->l_initfini; + if (runp != NULL) + /* Look through the dependencies of the object. */ + while (*runp != NULL) + if (__glibc_unlikely (*runp++ == thisp)) + { + /* Move the current object to the back past the last + object with it as the dependency. */ + memmove (&l_initfini[i], &l_initfini[i + 1], + (k - i) * sizeof (l_initfini[0])); + l_initfini[k] = thisp; + + if (seen[i + 1] > nlist - i) + { + ++i; + goto next_clear; + } + + uint16_t this_seen = seen[i]; + memmove (&seen[i], &seen[i + 1], + (k - i) * sizeof (seen[0])); + seen[k] = this_seen; + + goto next; + } + + --k; + } + + if (++i == nlist) + break; + next_clear: + memset (&seen[i], 0, (nlist - i) * sizeof (seen[0])); + + next:; + } + } + + /* Terminate the list of dependencies. */ + l_initfini[nlist] = NULL; + atomic_write_barrier (); + map->l_initfini = l_initfini; + map->l_free_initfini = 1; + if (l_reldeps != NULL) + { + atomic_write_barrier (); + void *old_l_reldeps = map->l_reldeps; + map->l_reldeps = l_reldeps; + _dl_scope_free (old_l_reldeps); + } + if (old_l_initfini != NULL) + _dl_scope_free (old_l_initfini); + + if (errno_reason) + _dl_signal_error (errno_reason == -1 ? 0 : errno_reason, objname, + NULL, errstring); +} |