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add RTLD_NODELETE support

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if RTLD_NODELETE isn't POSIX, it is widely deployed: at least linux,
freebsd, dragonfly, netbsd, solaris, illumos, apple, and fuchsia have
it.

ok kettenis@ on previous version
with help from and ok guenther@

diff partially inspired from a diff from brad@
This commit is contained in:
semarie 2021-06-02 07:29:03 +00:00
parent 9f67f65b7e
commit 296fbf9f7d
6 changed files with 33 additions and 12 deletions
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3
include/dlfcn.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: dlfcn.h,v 1.14 2017/11/28 17:19:47 kettenis Exp $ */
/* $OpenBSD: dlfcn.h,v 1.15 2021/06/02 07:29:03 semarie Exp $ */
/* $NetBSD: dlfcn.h,v 1.2 1995/06/05 19:38:00 pk Exp $ */
/*
@ -42,6 +42,7 @@
#define RTLD_GLOBAL 0x100
#define RTLD_LOCAL 0x000
#define RTLD_TRACE 0x200
#define RTLD_NODELETE 0x400
/*
* Special handle arguments for dlsym().

2
lib/libc/shlib_version
View File

@ -1,4 +1,4 @@
major=96
minor=0
minor=1
# note: If changes were made to include/thread_private.h or if system calls
# were added/changed then librthread/shlib_version must also be updated.

9
libexec/ld.so/dlfcn.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: dlfcn.c,v 1.106 2019/10/04 17:42:16 guenther Exp $ */
/* $OpenBSD: dlfcn.c,v 1.107 2021/06/02 07:29:03 semarie Exp $ */
/*
* Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@ -54,7 +54,7 @@ dlopen(const char *libname, int flags)
int failed = 0;
int obj_flags;
if (flags & ~(RTLD_TRACE|RTLD_LAZY|RTLD_NOW|RTLD_GLOBAL)) {
if (flags & ~(RTLD_TRACE|RTLD_LAZY|RTLD_NOW|RTLD_GLOBAL|RTLD_NODELETE)) {
_dl_errno = DL_INVALID_MODE;
return NULL;
}
@ -87,9 +87,14 @@ dlopen(const char *libname, int flags)
goto loaded;
}
if (flags & RTLD_NODELETE)
object->obj_flags |= DF_1_NODELETE;
_dl_link_dlopen(object);
if (OBJECT_REF_CNT(object) > 1) {
_dl_handle_nodelete(object);
/* if opened but grpsym_vec has not been filled in */
if (object->grpsym_vec.len == 0)
_dl_cache_grpsym_list_setup(object);

16
libexec/ld.so/resolve.c
View File

@ -1,4 +1,4 @@
/* $OpenBSD: resolve.c,v 1.94 2019/10/04 17:42:16 guenther Exp $ */
/* $OpenBSD: resolve.c,v 1.95 2021/06/02 07:29:03 semarie Exp $ */
/*
* Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@ -57,11 +57,8 @@ int object_count;
static elf_object_t *_dl_last_object;
elf_object_t *_dl_loading_object;
/*
* Add a new dynamic object to the object list.
*/
void
_dl_add_object(elf_object_t *object)
_dl_handle_nodelete(elf_object_t *object)
{
/*
* If a .so is marked nodelete, then the entire load group that it's
@ -76,6 +73,15 @@ _dl_add_object(elf_object_t *object)
object->load_object->opencount++;
object->load_object->status |= STAT_NODELETE;
}
}
/*
* Add a new dynamic object to the object list.
*/
void
_dl_add_object(elf_object_t *object)
{
_dl_handle_nodelete(object);
/*
* if this is a new object, prev will be NULL

3
libexec/ld.so/resolve.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: resolve.h,v 1.97 2021/03/16 18:03:06 kurt Exp $ */
/* $OpenBSD: resolve.h,v 1.98 2021/06/02 07:29:03 semarie Exp $ */
/*
* Copyright (c) 1998 Per Fogelstrom, Opsycon AB
@ -244,6 +244,7 @@ void _dl_debug_state(void);
extern char *__progname;
__BEGIN_HIDDEN_DECLS
void _dl_handle_nodelete(elf_object_t *_object);
void _dl_add_object(elf_object_t *object);
elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp,
Elf_Phdr *phdrp, int phdrc, const int objtype, const long lbase,

12
share/man/man3/dlfcn.3
View File

@ -1,4 +1,4 @@
.\" $OpenBSD: dlfcn.3,v 1.30 2020/12/03 22:47:22 jmc Exp $
.\" $OpenBSD: dlfcn.3,v 1.31 2021/06/02 07:29:03 semarie Exp $
.\" $NetBSD: dlfcn.3,v 1.3 1996/01/09 19:43:34 pk Exp $
.\"
.\" Copyright (c) 1995 Paul Kranenburg
@ -29,7 +29,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: December 3 2020 $
.Dd $Mdocdate: June 2 2021 $
.Dt DLOPEN 3
.Os
.Sh NAME
@ -124,6 +124,14 @@ each of the above values together.
If an object was opened with RTLD_LOCAL and later opened with RTLD_GLOBAL,
then it is promoted to RTLD_GLOBAL.
.Pp
Additionally, the following flag may be ORed into the mode argument:
.Pp
.Bl -tag -width "RTLD_NODELETE" -compact -offset indent
.It Sy RTLD_NODELETE
Prevents unload of the loaded object on
.Fn dlclose .
.El
.Pp
The main executable's symbols are normally invisible to
.Fn dlopen
symbol resolution.