Date: Tue, 16 Jun 2009 00:08:31 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: Maho NAKATA <chat95@mac.com> Cc: kan@freebsd.org, openoffice@freebsd.org Subject: Re: ld.so slight difference Linux and FreeBSD ports/127946 Message-ID: <20090615210831.GT23592@deviant.kiev.zoral.com.ua> In-Reply-To: <20090615.054654.71139727.chat95@mac.com> References: <1244902235.49065.33.camel@localhost> <20090614.081457.193757375.chat95@mac.com> <20090614094141.GF23592@deviant.kiev.zoral.com.ua> <20090615.054654.71139727.chat95@mac.com>
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On Mon, Jun 15, 2009 at 05:46:54AM +0900, Maho NAKATA wrote:
> Hi Konstantin,
>=20
> Your patch rocks! tested on FBSD7/i386 and it works!
>=20
> * Small test program works.
> * also PR 127946 and Issue 22253 went away.
> =20
> Is your patch can be commit to FBSD8 or MFC'ed to 7?
After discussion with Alexander, who pointed out that handles
returned from dlopen done over non-NULL name shall not search
in the namespace of objects opened with RTLD_GLOBAL flag,
I modified the patch.
Would be nice if you could retest the change below.
diff --git a/libexec/rtld-elf/rtld.c b/libexec/rtld-elf/rtld.c
index 40ed6ed..54acb8a 100644
--- a/libexec/rtld-elf/rtld.c
+++ b/libexec/rtld-elf/rtld.c
@@ -1048,9 +1048,13 @@ dlcheck(void *handle)
{
Obj_Entry *obj;
=20
- for (obj =3D obj_list; obj !=3D NULL; obj =3D obj->next)
- if (obj =3D=3D (Obj_Entry *) handle)
- break;
+ if (handle =3D=3D RTLD_HANDLE_FROM_NULL)
+ obj =3D obj_main;
+ else {
+ for (obj =3D obj_list; obj !=3D NULL; obj =3D obj->next)
+ if (obj =3D=3D (Obj_Entry *) handle)
+ break;
+ }
=20
if (obj =3D=3D NULL || obj->refcount =3D=3D 0 || obj->dl_refcount =3D=
=3D 0) {
_rtld_error("Invalid shared object handle %p", handle);
@@ -2054,6 +2058,8 @@ dlopen(const char *name, int mode)
objlist_call_init(&initlist, &lockstate);
objlist_clear(&initlist);
wlock_release(rtld_bind_lock, lockstate);
+ if (name =3D=3D NULL)
+ obj =3D RTLD_HANDLE_FROM_NULL;
return obj;
trace:
trace_loaded_objects(obj);
@@ -2069,7 +2075,7 @@ do_dlsym(void *handle, const char *name, void *retadd=
r, const Ver_Entry *ve,
const Obj_Entry *obj, *defobj;
const Elf_Sym *def, *symp;
unsigned long hash;
- int lockstate;
+ int lockstate, search_global;
=20
hash =3D elf_hash(name);
def =3D NULL;
@@ -2079,6 +2085,7 @@ do_dlsym(void *handle, const char *name, void *retadd=
r, const Ver_Entry *ve,
lockstate =3D rlock_acquire(rtld_bind_lock);
if (handle =3D=3D NULL || handle =3D=3D RTLD_NEXT ||
handle =3D=3D RTLD_DEFAULT || handle =3D=3D RTLD_SELF) {
+ search_global =3D true;
=20
if ((obj =3D obj_from_addr(retaddr)) =3D=3D NULL) {
_rtld_error("Cannot determine caller's shared object");
@@ -2120,6 +2127,7 @@ do_dlsym(void *handle, const char *name, void *retadd=
r, const Ver_Entry *ve,
def =3D symlook_default(name, hash, obj, &defobj, ve, flags);
}
} else {
+ search_global =3D (handle =3D=3D RTLD_HANDLE_FROM_NULL);
if ((obj =3D dlcheck(handle)) =3D=3D NULL) {
rlock_release(rtld_bind_lock, lockstate);
return NULL;
@@ -2141,6 +2149,11 @@ do_dlsym(void *handle, const char *name, void *retad=
dr, const Ver_Entry *ve,
&donelist);
}
}
+ if (def =3D=3D NULL && search_global) {
+ donelist_init(&donelist);
+ def =3D symlook_list(name, hash, &list_global, &defobj, ve, flags,
+ &donelist);
+ }
=20
if (def !=3D NULL) {
rlock_release(rtld_bind_lock, lockstate);
diff --git a/libexec/rtld-elf/rtld.h b/libexec/rtld-elf/rtld.h
index 2b3b897..b16e57e 100644
--- a/libexec/rtld-elf/rtld.h
+++ b/libexec/rtld-elf/rtld.h
@@ -238,6 +238,9 @@ typedef struct Struct_Obj_Entry {
#define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by
dlsym. */
=20
+/* Handle returned by dlopen(NULL, flags). */
+#define RTLD_HANDLE_FROM_NULL ((void *) -100)
+
/*
* Symbol cache entry used during relocation to avoid multiple lookups
* of the same symbol.
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