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Implement support -z global linker option. It marks the shared object

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as always participating in the global symbols namespace, regardless of
the way the object was brought into the process address space.

Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2015-04-15 08:16:34 +00:00
parent 316b384343
commit 3de3815469
2 changed files with 31 additions and 17 deletions
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47
libexec/rtld-elf/rtld.c
View File

@ -1158,8 +1158,8 @@ digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
obj->z_noopen = true;
if ((dynp->d_un.d_val & DF_1_ORIGIN) && trust)
obj->z_origin = true;
/*if (dynp->d_un.d_val & DF_1_GLOBAL)
XXX ;*/
if (dynp->d_un.d_val & DF_1_GLOBAL)
obj->z_global = true;
if (dynp->d_un.d_val & DF_1_BIND_NOW)
obj->bind_now = true;
if (dynp->d_un.d_val & DF_1_NODELETE)
@ -1790,22 +1790,35 @@ init_dag(Obj_Entry *root)
}
static void
process_nodelete(Obj_Entry *root)
process_z(Obj_Entry *root)
{
const Objlist_Entry *elm;
Obj_Entry *obj;
/*
* Walk over object DAG and process every dependent object that
* is marked as DF_1_NODELETE. They need to grow their own DAG,
* which then should have its reference upped separately.
* Walk over object DAG and process every dependent object
* that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need
* to grow their own DAG.
*
* For DF_1_GLOBAL, DAG is required for symbol lookups in
* symlook_global() to work.
*
* For DF_1_NODELETE, the DAG should have its reference upped.
*/
STAILQ_FOREACH(elm, &root->dagmembers, link) {
if (elm->obj != NULL && elm->obj->z_nodelete &&
!elm->obj->ref_nodel) {
dbg("obj %s nodelete", elm->obj->path);
init_dag(elm->obj);
ref_dag(elm->obj);
elm->obj->ref_nodel = true;
obj = elm->obj;
if (obj == NULL)
continue;
if (obj->z_nodelete && !obj->ref_nodel) {
dbg("obj %s -z nodelete", obj->path);
init_dag(obj);
ref_dag(obj);
obj->ref_nodel = true;
}
if (obj->z_global && objlist_find(&list_global, obj) == NULL) {
dbg("obj %s -z global", obj->path);
objlist_push_tail(&list_global, obj);
init_dag(obj);
}
}
}
@ -3044,13 +3057,13 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
initlist_add_objects(obj, &obj->next, &initlist);
}
/*
* Process all no_delete objects here, given them own
* DAGs to prevent their dependencies from being unloaded.
* This has to be done after we have loaded all of the
* dependencies, so that we do not miss any.
* Process all no_delete or global objects here, given
* them own DAGs to prevent their dependencies from being
* unloaded. This has to be done after we have loaded all
* of the dependencies, so that we do not miss any.
*/
if (obj != NULL)
process_nodelete(obj);
process_z(obj);
} else {
/*
* Bump the reference counts for objects on this DAG. If

1
libexec/rtld-elf/rtld.h
View File

@ -264,6 +264,7 @@ typedef struct Struct_Obj_Entry {
bool z_loadfltr : 1; /* Immediately load filtees */
bool z_interpose : 1; /* Interpose all objects but main */
bool z_nodeflib : 1; /* Don't search default library path */
bool z_global : 1; /* Make the object global */
bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
bool init_scanned: 1; /* Object is already on init list. */
bool on_fini_list: 1; /* Object is already on fini list. */