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Fix the buggy rev. 1.117. dagmembers are only initialized for dlopen'ed

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dso that are actually loading. If dso a.so depends on b.so, then dlsym
with handle from dlopen("b.so") will fail unconditionally.

Correct implementation shall use the Obj_Entry.needed list to walk
dependencies DAG.

Test provided by: jkim
Tested (prev. version) by:	jkim, Nicolas Blais <nb_root at videotron ca>, h.blanke at chello nl
Pointy hat to:	kib
Approved by:	kan (mentor)
This commit is contained in:
Konstantin Belousov 2006-09-19 12:47:13 +00:00
parent b58ab5f02a
commit 5fd885b07b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=162438
1 changed files with 63 additions and 5 deletions
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68
libexec/rtld-elf/rtld.c
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@ -125,6 +125,9 @@ static const Elf_Sym *symlook_default(const char *, unsigned long,
const Obj_Entry *, const Obj_Entry **, const Ver_Entry *, int);
static const Elf_Sym *symlook_list(const char *, unsigned long, const Objlist *,
const Obj_Entry **, const Ver_Entry *, int flags, DoneList *);
static const Elf_Sym *symlook_needed(const char *, unsigned long,
const Needed_Entry *, const Obj_Entry **, const Ver_Entry *,
int flags, DoneList *dlp);
static void trace_loaded_objects(Obj_Entry *obj);
static void unlink_object(Obj_Entry *);
static void unload_object(Obj_Entry *);
@ -1852,17 +1855,21 @@ do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve,
}
DoneList donelist;
const Objlist *srch_list;
donelist_init(&donelist);
if (obj->mainprog) {
/* Search main program and all libraries loaded by it. */
srch_list = &list_main;
def = symlook_list(name, hash, &list_main, &defobj, ve, flags,
&donelist);
} else {
Needed_Entry fake;
/* Search the whole DAG rooted at the given object. */
srch_list = &(obj->dagmembers);
fake.next = NULL;
fake.obj = (Obj_Entry *)obj;
fake.name = 0;
def = symlook_needed(name, hash, &fake, &defobj, ve, flags,
&donelist);
}
def = symlook_list(name, hash, srch_list, &defobj, ve, flags,
&donelist);
}
if (def != NULL) {
@ -2361,6 +2368,57 @@ symlook_list(const char *name, unsigned long hash, const Objlist *objlist,
return def;
}
/*
* Search the symbol table of a shared object and all objects needed
* by it for a symbol of the given name. Search order is
* breadth-first. Returns a pointer to the symbol, or NULL if no
* definition was found.
*/
static const Elf_Sym *
symlook_needed(const char *name, unsigned long hash, const Needed_Entry *needed,
const Obj_Entry **defobj_out, const Ver_Entry *ventry, int flags,
DoneList *dlp)
{
const Elf_Sym *def, *def_w;
const Needed_Entry *n;
const Obj_Entry *obj, *defobj, *defobj1;
def = def_w = NULL;
defobj = NULL;
for (n = needed; n != NULL; n = n->next) {
if ((obj = n->obj) == NULL ||
donelist_check(dlp, obj) ||
(def = symlook_obj(name, hash, obj, ventry, flags)) == NULL)
continue;
defobj = obj;
if (ELF_ST_BIND(def->st_info) != STB_WEAK) {
*defobj_out = defobj;
return (def);
}
}
/*
* There we come when either symbol definition is not found in
* directly needed objects, or found symbol is weak.
*/
for (n = needed; n != NULL; n = n->next) {
if ((obj = n->obj) == NULL)
continue;
def_w = symlook_needed(name, hash, obj->needed, &defobj1,
ventry, flags, dlp);
if (def_w == NULL)
continue;
if (def == NULL || ELF_ST_BIND(def_w->st_info) != STB_WEAK) {
def = def_w;
defobj = defobj1;
}
if (ELF_ST_BIND(def_w->st_info) != STB_WEAK)
break;
}
if (def != NULL)
*defobj_out = defobj;
return def;
}
/*
* Search the symbol table of a single shared object for a symbol of
* the given name and version, if requested. Returns a pointer to the