From a3640c7517a4f7b3754381d7feb90cda77ac48a3 Mon Sep 17 00:00:00 2001
From: Mark Kettenis <kettenis@gnu.org>
Date: Sun, 9 Nov 2003 17:28:08 +0000
Subject: * glibc-tdep.c, glibc-tdep.h: New files. * config/arm/linux.mt
 (TDEPFILES): Add glibc-tdep.o * config/i386/linux.mt (TDEPFILES): Likewise. *
 i386-linux-tdep.c (glibc-tdep.h): Include. (find_minsym_and_objfile,
 skip_hurd_resolver): Delete. (i386_linux_skip_solib_resolver): Call
 glibc_skip_solib_resolver. * arm-linux-tdep.c (glibc-tdep.h): Include.
 (find_minsym_and_objfile, skip_hurd_resolver): Delete.
 (arm_linux_skip_solib_resolver): Call glibc_skip_solib_resolver. *
 Makefile.in (ALLDEPFILES): Add glibc-tdep.c (glibc_tdep_h): Define.
 (glibc-tdep.o): Add dependencies. (arm-linux-tdep.o): Update dependencies.
 (i386-linux-tdep.o): Likewise.

---
 gdb/glibc-tdep.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 gdb/glibc-tdep.c

(limited to 'gdb/glibc-tdep.c')

diff --git a/gdb/glibc-tdep.c b/gdb/glibc-tdep.c
new file mode 100644
index 0000000..46aa749
--- /dev/null
+++ b/gdb/glibc-tdep.c
@@ -0,0 +1,101 @@
+/* Target-dependent code for the GNU C Library (glibc).
+
+   Copyright 2002, 2003 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include "defs.h"
+#include "frame.h"
+#include "symtab.h"
+#include "symfile.h"
+#include "objfiles.h"
+
+#include "glibc-tdep.h"
+
+/* Calling functions in shared libraries.  */
+
+/* Find the minimal symbol named NAME, and return both the minsym
+   struct and its objfile.  This probably ought to be in minsym.c, but
+   everything there is trying to deal with things like C++ and
+   SOFUN_ADDRESS_MAYBE_TURQUOISE, ...  Since this is so simple, it may
+   be considered too special-purpose for general consumption.  */
+
+static struct minimal_symbol *
+find_minsym_and_objfile (char *name, struct objfile **objfile_p)
+{
+  struct objfile *objfile;
+
+  ALL_OBJFILES (objfile)
+    {
+      struct minimal_symbol *msym;
+
+      ALL_OBJFILE_MSYMBOLS (objfile, msym)
+	{
+	  if (SYMBOL_LINKAGE_NAME (msym)
+	      && strcmp (SYMBOL_LINKAGE_NAME (msym), name) == 0)
+	    {
+	      *objfile_p = objfile;
+	      return msym;
+	    }
+	}
+    }
+
+  return 0;
+}
+
+/* See the comments for SKIP_SOLIB_RESOLVER at the top of infrun.c.
+   This function:
+   1) decides whether a PLT has sent us into the linker to resolve
+      a function reference, and 
+   2) if so, tells us where to set a temporary breakpoint that will
+      trigger when the dynamic linker is done.  */
+
+CORE_ADDR
+glibc_skip_solib_resolver (CORE_ADDR pc)
+{
+  /* The GNU dynamic linker is part of the GNU C library, and is used
+     by all GNU systems (GNU/Hurd, GNU/Linux).  An unresolved PLT
+     entry points to "_dl_runtime_resolve", which calls "fixup" to
+     patch the PLT, and then passes control to the function.
+
+     We look for the symbol `_dl_runtime_resolve', and find `fixup' in
+     the same objfile.  If we are at the entry point of `fixup', then
+     we set a breakpoint at the return address (at the top of the
+     stack), and continue.
+  
+     It's kind of gross to do all these checks every time we're
+     called, since they don't change once the executable has gotten
+     started.  But this is only a temporary hack --- upcoming versions
+     of GNU/Linux will provide a portable, efficient interface for
+     debugging programs that use shared libraries.  */
+
+  struct objfile *objfile;
+  struct minimal_symbol *resolver 
+    = find_minsym_and_objfile ("_dl_runtime_resolve", &objfile);
+
+  if (resolver)
+    {
+      struct minimal_symbol *fixup
+	= lookup_minimal_symbol ("fixup", NULL, objfile);
+
+      if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
+	return frame_pc_unwind (get_current_frame ());
+    }
+
+  return 0;
+}      
-- 
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