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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/elf/dl-debug.c
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
downloadglibc-zack/build-layout-experiment.tar.gz
glibc-zack/build-layout-experiment.tar.xz
glibc-zack/build-layout-experiment.zip
Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/elf/dl-debug.c')
-rw-r--r--REORG.TODO/elf/dl-debug.c76
1 files changed, 76 insertions, 0 deletions
diff --git a/REORG.TODO/elf/dl-debug.c b/REORG.TODO/elf/dl-debug.c
new file mode 100644
index 0000000000..f3957044f6
--- /dev/null
+++ b/REORG.TODO/elf/dl-debug.c
@@ -0,0 +1,76 @@
+/* Communicate dynamic linker state to the debugger at runtime.
+   Copyright (C) 1996-2017 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
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <ldsodefs.h>
+
+
+/* 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];
+
+/* 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;
+
+
+/* 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.  */
+
+struct r_debug *
+internal_function
+_dl_debug_initialize (ElfW(Addr) ldbase, Lmid_t ns)
+{
+  struct r_debug *r;
+
+  if (ns == LM_ID_BASE)
+    r = &_r_debug;
+  else
+    r = &GL(dl_ns)[ns]._ns_debug;
+
+  if (r->r_map == NULL || ldbase != 0)
+    {
+      /* 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 = (void *) GL(dl_ns)[ns]._ns_loaded;
+      r->r_brk = (ElfW(Addr)) &_dl_debug_state;
+    }
+
+  return r;
+}
+
+
+/* This function exists solely to have a breakpoint set on it by the
+   debugger.  The debugger is supposed to find this function's address by
+   examining the r_brk member of struct r_debug, but GDB 4.15 in fact looks
+   for this particular symbol name in the PT_INTERP file.  */
+void
+_dl_debug_state (void)
+{
+}
+rtld_hidden_def (_dl_debug_state)