562 lines
16 KiB
C
562 lines
16 KiB
C
/* Load the dependencies of a mapped object.
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Copyright (C) 1996,1997,1998,1999,2000,2001 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, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <dlfcn.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 <unistd.h>
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#include <sys/param.h>
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#include <ldsodefs.h>
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#include <dl-dst.h>
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/* Whether an shared object references one or more auxiliary objects
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is signaled by the AUXTAG entry in l_info. */
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#define AUXTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
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+ DT_EXTRATAGIDX (DT_AUXILIARY))
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/* Whether an shared object references one or more auxiliary objects
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is signaled by the AUXTAG entry in l_info. */
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#define FILTERTAG (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGNUM \
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+ DT_EXTRATAGIDX (DT_FILTER))
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/* This is zero at program start to signal that the global scope map is
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allocated by rtld. Later it keeps the size of the map. It might be
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reset if in _dl_close if the last global object is removed. */
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size_t _dl_global_scope_alloc;
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extern size_t _dl_platformlen;
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/* When loading auxiliary objects we must ignore errors. It's ok if
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an object is missing. */
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struct openaux_args
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{
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/* The arguments to openaux. */
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struct link_map *map;
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int trace_mode;
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const char *strtab;
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const char *name;
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/* The return value of openaux. */
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struct link_map *aux;
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};
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static void
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openaux (void *a)
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{
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struct openaux_args *args = (struct openaux_args *) a;
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args->aux = _dl_map_object (args->map, args->name, 0,
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(args->map->l_type == lt_executable
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? lt_library : args->map->l_type),
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args->trace_mode, 0);
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}
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/* We use a very special kind of list to track the path
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through the list of loaded shared objects. We have to
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produce a flat list with unique members of all involved objects.
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*/
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struct list
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{
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int done; /* Nonzero if this map was processed. */
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struct link_map *map; /* The data. */
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struct list *next; /* Elements for normal list. */
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};
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/* Macro to expand DST. It is an macro since we use `alloca'. */
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#define expand_dst(l, str, fatal) \
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({ \
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const char *__str = (str); \
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const char *__result = __str; \
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size_t __cnt = DL_DST_COUNT(__str, 0); \
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\
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if (__cnt != 0) \
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{ \
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char *__newp; \
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\
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__newp = (char *) alloca (DL_DST_REQUIRED (l, __str, strlen (__str), \
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__cnt)); \
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\
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__result = DL_DST_SUBSTITUTE (l, __str, __newp, 0); \
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\
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if (*__result == '\0') \
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{ \
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/* The replacement for the DST is not known. We can't \
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processed. */ \
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if (fatal) \
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_dl_signal_error (0, __str, NULL, N_("\
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empty dynamics string token substitution")); \
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else \
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{ \
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/* This is for DT_AUXILIARY. */ \
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if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0)) \
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_dl_debug_printf ("cannot load auxiliary `%s' because of" \
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"empty dynamic string token " \
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"substitution\n", __str); \
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continue; \
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} \
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} \
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} \
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\
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__result; })
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void
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internal_function
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_dl_map_object_deps (struct link_map *map,
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struct link_map **preloads, unsigned int npreloads,
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int trace_mode)
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{
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struct list known[1 + npreloads + 1];
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struct list *runp, *tail;
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unsigned int nlist, i;
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/* Object name. */
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const char *name;
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int errno_saved;
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int errno_reason;
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const char *errstring;
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const char *objname;
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auto inline void preload (struct link_map *map);
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inline void preload (struct link_map *map)
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{
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known[nlist].done = 0;
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known[nlist].map = map;
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known[nlist].next = &known[nlist + 1];
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++nlist;
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/* We use `l_reserved' as a mark bit to detect objects we have
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already put in the search list and avoid adding duplicate
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elements later in the list. */
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map->l_reserved = 1;
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}
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/* No loaded object so far. */
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nlist = 0;
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/* First load MAP itself. */
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preload (map);
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/* Add the preloaded items after MAP but before any of its dependencies. */
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for (i = 0; i < npreloads; ++i)
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preload (preloads[i]);
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/* Terminate the lists. */
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known[nlist - 1].next = NULL;
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/* Pointer to last unique object. */
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tail = &known[nlist - 1];
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/* Process each element of the search list, loading each of its
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auxiliary objects and immediate dependencies. Auxiliary objects
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will be added in the list before the object itself and
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dependencies will be appended to the list as we step through it.
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This produces a flat, ordered list that represents a
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breadth-first search of the dependency tree.
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The whole process is complicated by the fact that we better
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should use alloca for the temporary list elements. But using
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alloca means we cannot use recursive function calls. */
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errno_saved = errno;
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errno_reason = 0;
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errstring = NULL;
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errno = 0;
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name = NULL;
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for (runp = known; runp; )
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{
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struct link_map *l = runp->map;
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struct link_map **needed = NULL;
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unsigned int nneeded = 0;
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/* Unless otherwise stated, this object is handled. */
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runp->done = 1;
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/* Allocate a temporary record to contain the references to the
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dependencies of this object. */
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if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL
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&& l != map && l->l_ldnum > 0)
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needed = (struct link_map **) alloca (l->l_ldnum
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* sizeof (struct link_map *));
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if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG])
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{
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const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
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struct openaux_args args;
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struct list *orig;
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const ElfW(Dyn) *d;
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args.strtab = strtab;
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args.map = l;
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args.trace_mode = trace_mode;
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orig = runp;
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for (d = l->l_ld; d->d_tag != DT_NULL; ++d)
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if (__builtin_expect (d->d_tag, DT_NEEDED) == DT_NEEDED)
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{
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/* Map in the needed object. */
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struct link_map *dep;
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int err;
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/* Recognize DSTs. */
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name = expand_dst (l, strtab + d->d_un.d_val, 0);
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/* Store the tag in the argument structure. */
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args.name = name;
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err = _dl_catch_error (&objname, &errstring, openaux, &args);
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if (__builtin_expect (errstring != NULL, 0))
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{
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if (err)
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errno_reason = err;
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else
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errno_reason = -1;
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goto out;
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}
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else
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dep = args.aux;
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if (! dep->l_reserved)
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{
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/* Allocate new entry. */
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struct list *newp;
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newp = alloca (sizeof (struct list));
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/* Append DEP to the list. */
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newp->map = dep;
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newp->done = 0;
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newp->next = NULL;
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tail->next = newp;
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tail = newp;
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++nlist;
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/* Set the mark bit that says it's already in the list. */
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dep->l_reserved = 1;
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}
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/* Remember this dependency. */
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if (needed != NULL)
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needed[nneeded++] = dep;
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}
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else if (d->d_tag == DT_AUXILIARY || d->d_tag == DT_FILTER)
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{
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struct list *newp;
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/* Recognize DSTs. */
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name = expand_dst (l, strtab + d->d_un.d_val,
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d->d_tag == DT_AUXILIARY);
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/* Store the tag in the argument structure. */
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args.name = name;
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if (d->d_tag == DT_AUXILIARY)
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{
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int err;
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/* Say that we are about to load an auxiliary library. */
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if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
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_dl_debug_printf ("load auxiliary object=%s"
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" requested by file=%s\n", name,
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l->l_name[0]
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? l->l_name : _dl_argv[0]);
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/* We must be prepared that the addressed shared
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object is not available. */
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err = _dl_catch_error (&objname, &errstring, openaux,
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&args);
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if (__builtin_expect (errstring != NULL, 0))
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{
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/* We are not interested in the error message. */
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assert (errstring != NULL);
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if (errstring != _dl_out_of_memory)
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free ((char *) errstring);
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/* Simply ignore this error and continue the work. */
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continue;
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}
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}
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else
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{
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int err;
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/* Say that we are about to load an auxiliary library. */
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if (__builtin_expect (_dl_debug_mask & DL_DEBUG_LIBS, 0))
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_dl_debug_printf ("load filtered object=%s"
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" requested by file=%s\n", name,
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l->l_name[0]
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? l->l_name : _dl_argv[0]);
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/* For filter objects the dependency must be available. */
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err = _dl_catch_error (&objname, &errstring, openaux,
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&args);
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if (__builtin_expect (errstring != NULL, 0))
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{
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if (err)
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errno_reason = err;
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else
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errno_reason = -1;
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goto out;
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}
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}
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/* The auxiliary object is actually available.
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Incorporate the map in all the lists. */
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/* Allocate new entry. This always has to be done. */
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newp = alloca (sizeof (struct list));
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/* We want to insert the new map before the current one,
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but we have no back links. So we copy the contents of
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the current entry over. Note that ORIG and NEWP now
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have switched their meanings. */
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memcpy (newp, orig, sizeof (*newp));
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/* Initialize new entry. */
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orig->done = 0;
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orig->map = args.aux;
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/* Remember this dependency. */
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if (needed != NULL)
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needed[nneeded++] = args.aux;
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/* We must handle two situations here: the map is new,
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so we must add it in all three lists. If the map
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is already known, we have two further possibilities:
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- if the object is before the current map in the
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search list, we do nothing. It is already found
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early
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- if the object is after the current one, we must
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move it just before the current map to make sure
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the symbols are found early enough
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*/
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if (args.aux->l_reserved)
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{
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/* The object is already somewhere in the list.
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Locate it first. */
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struct list *late;
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/* This object is already in the search list we
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are building. Don't add a duplicate pointer.
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Just added by _dl_map_object. */
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for (late = newp; late->next != NULL; late = late->next)
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if (late->next->map == args.aux)
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break;
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if (late->next != NULL)
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{
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/* The object is somewhere behind the current
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position in the search path. We have to
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move it to this earlier position. */
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orig->next = newp;
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/* Now remove the later entry from the list
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and adjust the tail pointer. */
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if (tail == late->next)
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tail = late;
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late->next = late->next->next;
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/* We must move the object earlier in the chain. */
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if (args.aux->l_prev != NULL)
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args.aux->l_prev->l_next = args.aux->l_next;
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if (args.aux->l_next != NULL)
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args.aux->l_next->l_prev = args.aux->l_prev;
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args.aux->l_prev = newp->map->l_prev;
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newp->map->l_prev = args.aux;
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if (args.aux->l_prev != NULL)
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args.aux->l_prev->l_next = args.aux;
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args.aux->l_next = newp->map;
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}
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else
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{
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/* The object must be somewhere earlier in the
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list. Undo to the current list element what
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we did above. */
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memcpy (orig, newp, sizeof (*newp));
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continue;
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}
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}
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else
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{
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/* This is easy. We just add the symbol right here. */
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orig->next = newp;
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++nlist;
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/* Set the mark bit that says it's already in the list. */
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args.aux->l_reserved = 1;
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/* The only problem is that in the double linked
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list of all objects we don't have this new
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object at the correct place. Correct this here. */
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if (args.aux->l_prev)
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args.aux->l_prev->l_next = args.aux->l_next;
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if (args.aux->l_next)
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args.aux->l_next->l_prev = args.aux->l_prev;
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args.aux->l_prev = newp->map->l_prev;
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newp->map->l_prev = args.aux;
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if (args.aux->l_prev != NULL)
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args.aux->l_prev->l_next = args.aux;
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args.aux->l_next = newp->map;
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}
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/* Move the tail pointer if necessary. */
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if (orig == tail)
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tail = newp;
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/* Move on the insert point. */
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orig = newp;
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}
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}
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/* Terminate the list of dependencies and store the array address. */
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if (needed != NULL)
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{
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needed[nneeded++] = NULL;
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l->l_initfini = (struct link_map **)
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malloc ((nneeded + 1) * sizeof needed[0]);
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if (l->l_initfini == NULL)
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_dl_signal_error (ENOMEM, map->l_name, NULL,
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N_("cannot allocate dependency list"));
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l->l_initfini[0] = l;
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memcpy (&l->l_initfini[1], needed, nneeded * sizeof needed[0]);
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}
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/* If we have no auxiliary objects just go on to the next map. */
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if (runp->done)
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do
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runp = runp->next;
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while (runp != NULL && runp->done);
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}
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out:
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if (errno == 0 && errno_saved != 0)
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__set_errno (errno_saved);
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if (map->l_initfini != NULL && map->l_type == lt_loaded)
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{
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/* This object was previously loaded as a dependency and we have
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a separate l_initfini list. We don't need it anymore. */
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assert (map->l_searchlist.r_list == NULL);
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free (map->l_initfini);
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}
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/* Store the search list we built in the object. It will be used for
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searches in the scope of this object. */
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map->l_initfini =
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(struct link_map **) malloc ((2 * nlist + 1)
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* sizeof (struct link_map *));
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if (map->l_initfini == NULL)
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_dl_signal_error (ENOMEM, map->l_name, NULL,
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N_("cannot allocate symbol search list"));
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map->l_searchlist.r_list = &map->l_initfini[nlist + 1];
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map->l_searchlist.r_nlist = nlist;
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for (nlist = 0, runp = known; runp; runp = runp->next)
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{
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if (__builtin_expect (trace_mode, 0) && runp->map->l_faked)
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/* This can happen when we trace the loading. */
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--map->l_searchlist.r_nlist;
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else
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map->l_searchlist.r_list[nlist++] = runp->map;
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/* Now clear all the mark bits we set in the objects on the search list
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to avoid duplicates, so the next call starts fresh. */
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runp->map->l_reserved = 0;
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}
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/* Maybe we can remove some relocation dependencies now. */
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assert (map->l_searchlist.r_list[0] == map);
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for (i = 0; i < map->l_reldepsact; ++i)
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{
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unsigned int j;
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for (j = 1; j < nlist; ++j)
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if (map->l_searchlist.r_list[j] == map->l_reldeps[i])
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{
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/* A direct or transitive dependency is also on the list
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of relocation dependencies. Remove the latter. */
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--map->l_reldeps[i]->l_opencount;
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for (j = i + 1; j < map->l_reldepsact; ++j)
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map->l_reldeps[j - 1] = map->l_reldeps[j];
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--map->l_reldepsact;
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/* Account for the '++i' performed by the 'for'. */
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--i;
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break;
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}
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}
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/* Now determine the order in which the initialization has to happen. */
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memcpy (map->l_initfini, map->l_searchlist.r_list,
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nlist * sizeof (struct link_map *));
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/* We can skip looking for the binary itself which is at the front
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of the search list. Look through the list backward so that circular
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dependencies are not changing the order. */
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for (i = 1; i < nlist; ++i)
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{
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struct link_map *l = map->l_searchlist.r_list[i];
|
|
unsigned int j;
|
|
unsigned int k;
|
|
|
|
/* Find the place in the initfini list where the map is currently
|
|
located. */
|
|
for (j = 1; map->l_initfini[j] != l; ++j)
|
|
;
|
|
|
|
/* Find all object for which the current one is a dependency and
|
|
move the found object (if necessary) in front. */
|
|
for (k = j + 1; k < nlist; ++k)
|
|
{
|
|
struct link_map **runp;
|
|
|
|
runp = map->l_initfini[k]->l_initfini;
|
|
if (runp != NULL)
|
|
{
|
|
while (*runp != NULL)
|
|
if (__builtin_expect (*runp++ == l, 0))
|
|
{
|
|
struct link_map *here = map->l_initfini[k];
|
|
|
|
/* Move it now. */
|
|
memmove (&map->l_initfini[j] + 1,
|
|
&map->l_initfini[j],
|
|
(k - j) * sizeof (struct link_map *));
|
|
map->l_initfini[j] = here;
|
|
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
/* Terminate the list of dependencies. */
|
|
map->l_initfini[nlist] = NULL;
|
|
|
|
if (errno_reason)
|
|
_dl_signal_error (errno_reason == -1 ? 0 : errno_reason,
|
|
objname, NULL, errstring);
|
|
}
|