/* Communicate dynamic linker state to the debugger at runtime.
- Copyright (C) 1996, 1998,2000,2002,2004,2005 Free Software Foundation, Inc.
+ Copyright (C) 1996-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
-/* This structure communicates dl state to the debugger. The debugger
- normally finds it via the DT_DEBUG entry in the dynamic section, but in
- a statically-linked program there is no dynamic section for the debugger
- to examine and it looks for this particular symbol name. */
-struct r_debug _r_debug;
+/* These are the members in the public `struct link_map' type.
+ Sanity check that the internal type and the public type match. */
+#define VERIFY_MEMBER(name) \
+ (offsetof (struct link_map_public, name) == offsetof (struct link_map, name))
+extern const int verify_link_map_members[(VERIFY_MEMBER (l_addr)
+ && VERIFY_MEMBER (l_name)
+ && VERIFY_MEMBER (l_ld)
+ && VERIFY_MEMBER (l_next)
+ && VERIFY_MEMBER (l_prev))
+ ? 1 : -1];
-/* Initialize _r_debug if it has not already been done. The argument is
- the run-time load address of the dynamic linker, to be put in
- _r_debug.r_ldbase. Returns the address of _r_debug. */
+/* Update the `r_map' member and return the address of `struct r_debug'
+ of the namespace NS. */
struct r_debug *
-internal_function
-_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
+_dl_debug_update (Lmid_t ns)
{
- struct r_debug *r;
-
+ struct r_debug_extended *r;
if (ns == LM_ID_BASE)
- r = &_r_debug;
+ r = &_r_debug_extended;
else
r = &GL(dl_ns)[ns]._ns_debug;
+ if (r->base.r_map == NULL)
+ atomic_store_release (&r->base.r_map,
+ (void *) GL(dl_ns)[ns]._ns_loaded);
+ return &r->base;
+}
+
+/* Initialize _r_debug_extended for the namespace NS. LDBASE is the
+ run-time load address of the dynamic linker, to be put in
+ _r_debug_extended.r_ldbase. Return the address of _r_debug. */
+
+struct r_debug *
+_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
+{
+ struct r_debug_extended *r, **pp = NULL;
+
+ if (ns == LM_ID_BASE)
+ {
+ r = &_r_debug_extended;
+ /* Initialize r_version to 1. */
+ if (_r_debug_extended.base.r_version == 0)
+ _r_debug_extended.base.r_version = 1;
+ }
+ else if (DL_NNS > 1)
+ {
+ r = &GL(dl_ns)[ns]._ns_debug;
+ if (r->base.r_brk == 0)
+ {
+ /* Add the new namespace to the linked list. After a namespace
+ is initialized, r_brk becomes non-zero. A namespace becomes
+ empty (r_map == NULL) when it is unused. But it is never
+ removed from the linked list. */
+ struct r_debug_extended *p;
+ for (pp = &_r_debug_extended.r_next;
+ (p = *pp) != NULL;
+ pp = &p->r_next)
+ ;
+
+ r->base.r_version = 2;
+ }
+ }
+
+ if (r->base.r_brk == 0)
+ {
+ /* Tell the debugger where to find the map of loaded objects.
+ This function is called from dlopen. Initialize the namespace
+ only once. */
+ r->base.r_ldbase = ldbase ?: _r_debug_extended.base.r_ldbase;
+ r->base.r_brk = (ElfW(Addr)) &_dl_debug_state;
+ r->r_next = NULL;
+ }
+
+ if (r->base.r_map == NULL)
+ atomic_store_release (&r->base.r_map,
+ (void *) GL(dl_ns)[ns]._ns_loaded);
- if (r->r_brk == 0 || ldbase != 0)
+ if (pp != NULL)
{
- /* Tell the debugger where to find the map of loaded objects. */
- r->r_version = 1 /* R_DEBUG_VERSION XXX */;
- r->r_ldbase = ldbase ?: _r_debug.r_ldbase;
- r->r_map = GL(dl_ns)[ns]._ns_loaded;
- r->r_brk = (ElfW(Addr)) &_dl_debug_state;
+ atomic_store_release (pp, r);
+ /* Bump r_version to 2 for the new namespace. */
+ atomic_store_release (&_r_debug_extended.base.r_version, 2);
}
- return r;
+ return &r->base;
}