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Implement support for the interpose dso flag.

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Requested by:	bf
Reviewed by:	kan
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Approved by:	re (glebius)
This commit is contained in:
Konstantin Belousov 2013-10-07 08:19:30 +00:00
parent ed1bfa0c21
commit 3cf98c19e8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=256101
2 changed files with 33 additions and 2 deletions
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34
libexec/rtld-elf/rtld.c
View File

@ -116,6 +116,7 @@ static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *);
static void objlist_init(Objlist *);
static void objlist_push_head(Objlist *, Obj_Entry *);
static void objlist_push_tail(Objlist *, Obj_Entry *);
static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *);
static void objlist_remove(Objlist *, Obj_Entry *);
static void *path_enumerate(const char *, path_enum_proc, void *);
static int relocate_object_dag(Obj_Entry *root, bool bind_now,
@ -323,6 +324,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
Objlist_Entry *entry;
Obj_Entry *obj;
Obj_Entry **preload_tail;
Obj_Entry *last_interposer;
Objlist initlist;
RtldLockState lockstate;
char *library_path_rpath;
@ -537,8 +539,14 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp)
die();
/* Make a list of all objects loaded at startup. */
last_interposer = obj_main;
for (obj = obj_list; obj != NULL; obj = obj->next) {
objlist_push_tail(&list_main, obj);
if (obj->z_interpose && obj != obj_main) {
objlist_put_after(&list_main, last_interposer, obj);
last_interposer = obj;
} else {
objlist_push_tail(&list_main, obj);
}
obj->refcount++;
}
@ -1128,6 +1136,8 @@ digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath,
obj->z_nodelete = true;
if (dynp->d_un.d_val & DF_1_LOADFLTR)
obj->z_loadfltr = true;
if (dynp->d_un.d_val & DF_1_INTERPOSE)
obj->z_interpose = true;
if (dynp->d_un.d_val & DF_1_NODEFLIB)
obj->z_nodeflib = true;
break;
@ -1976,6 +1986,7 @@ static int
load_preload_objects(void)
{
char *p = ld_preload;
Obj_Entry *obj;
static const char delim[] = " \t:;";
if (p == NULL)
@ -1988,8 +1999,10 @@ load_preload_objects(void)
savech = p[len];
p[len] = '\0';
if (load_object(p, -1, NULL, 0) == NULL)
obj = load_object(p, -1, NULL, 0);
if (obj == NULL)
return -1; /* XXX - cleanup */
obj->z_interpose = true;
p[len] = savech;
p += len;
p += strspn(p, delim);
@ -2377,6 +2390,23 @@ objlist_push_tail(Objlist *list, Obj_Entry *obj)
STAILQ_INSERT_TAIL(list, elm, link);
}
static void
objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj)
{
Objlist_Entry *elm, *listelm;
STAILQ_FOREACH(listelm, list, link) {
if (listelm->obj == listobj)
break;
}
elm = NEW(Objlist_Entry);
elm->obj = obj;
if (listelm != NULL)
STAILQ_INSERT_AFTER(list, listelm, elm, link);
else
STAILQ_INSERT_TAIL(list, elm, link);
}
static void
objlist_remove(Objlist *list, Obj_Entry *obj)
{

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

@ -259,6 +259,7 @@ typedef struct Struct_Obj_Entry {
bool z_nodelete : 1; /* Do not unload the object and dependencies */
bool z_noopen : 1; /* Do not load on dlopen */
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 ref_nodel : 1; /* Refcount increased to prevent dlclose */
bool init_scanned: 1; /* Object is already on init list. */