From 2536cf64633e7334d1c04bc865907feee5128fdb Mon Sep 17 00:00:00 2001
From: Lubomir Kundrak <lkundrak@redhat.com>
Date: Sun, 13 Nov 2011 22:59:46 +0100
Subject: [PATCH] 	Add facility to debug GRUB with gdb under qemu.

	* grub-core/gdb_grub.in: New file.
	* grub-core/gmodule.pl.in: Likewise.
	* grub-core/Makefile.core.def (gmodule.pl): New script.
	(gdb_grub): Likewise.
---
 ChangeLog                   |  9 ++++
 grub-core/Makefile.core.def | 12 ++++++
 grub-core/gdb_grub.in       | 82 +++++++++++++++++++++++++++++++++++++
 grub-core/gmodule.pl.in     | 30 ++++++++++++++
 4 files changed, 133 insertions(+)
 create mode 100644 grub-core/gdb_grub.in
 create mode 100644 grub-core/gmodule.pl.in

diff --git a/ChangeLog b/ChangeLog
index d3c48339e..22421a715 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2011-11-13  Lubomir Kundrak  <lkundrak@redhat.com>
+
+	Add facility to debug GRUB with gdb under qemu.
+
+	* grub-core/gdb_grub.in: New file.
+	* grub-core/gmodule.pl.in: Likewise.
+	* grub-core/Makefile.core.def (gmodule.pl): New script.
+	(gdb_grub): Likewise.
+
 2011-11-13  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	* util/grub-mount.c (argp_parser): Accept relative pathes.
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index fc0472d32..cae79b381 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -18,6 +18,18 @@ script = {
   common = modinfo.sh.in;
 };
 
+script = {
+  installdir = noinst;
+  name = gmodule.pl;
+  common = gmodule.pl.in;
+};
+
+script = {
+  installdir = noinst;
+  name = gdb_grub;
+  common = gdb_grub.in;
+};
+
 kernel = {
   name = kernel;
 
diff --git a/grub-core/gdb_grub.in b/grub-core/gdb_grub.in
new file mode 100644
index 000000000..4a55233da
--- /dev/null
+++ b/grub-core/gdb_grub.in
@@ -0,0 +1,82 @@
+###
+### Load debuging information about GNU GRUB 2 modules into GDB
+### automatically. Needs readelf, Perl and gmodule.pl script
+###
+### $Id: .gdbinit,v 1.1 2006/05/14 11:38:08 lkundrak Exp $
+### Lubomir Kundrak <lkudrak@skosi.org>
+###
+
+# Add section numbers and addresses to .segments.tmp
+define dump_module_sections
+	set $mod = $arg0
+
+	# FIXME: save logging status
+	set logging file .segments.tmp
+	set logging redirect on
+	set logging overwrite off
+	set logging on
+
+	printf "%s", $mod->name
+	set $segment = $mod->segment
+	while ($segment)
+		printf " %i 0x%x", $segment->section, $segment->addr
+		set $segment = $segment->next
+	end
+	printf "\n"
+
+	set logging off
+	# FIXME: restore logging status
+end
+document dump_module_sections
+	Gather information about module whose mod structure was
+	given for use with match_and_load_symbols
+end
+
+# Generate and execute GDB commands and delete temporary files
+# afterwards
+define match_and_load_symbols
+	shell perl gmodule.pl <.segments.tmp >.loadsym.gdb
+	source .loadsym.gdb
+	shell rm -f .segments.tmp .loadsym.gdb
+end
+document match_and_load_symbols
+	Launch script, that matches section names with information
+	generated by dump_module_sections and load debugging info
+	apropriately
+end
+
+###
+
+define load_module
+	dump_module_sections $arg0
+	match_and_load_symbols
+end
+document load_module
+	Load debugging information for module given as argument.
+end
+
+define load_all_modules
+	set $this = grub_dl_head
+	while ($this != 0)
+		dump_module_sections $this->mod
+		set $this = $this->next
+	end
+	match_and_load_symbols
+end
+document load_all_modules
+	Load debugging information for all loaded modules.
+end
+
+###
+
+set confirm off
+file kernel.exec
+target remote :1234
+
+# inform when module is loaded
+break grub_dl_add
+commands
+	silent
+	load_module mod
+	cont
+end
diff --git a/grub-core/gmodule.pl.in b/grub-core/gmodule.pl.in
new file mode 100644
index 000000000..6739a6f1c
--- /dev/null
+++ b/grub-core/gmodule.pl.in
@@ -0,0 +1,30 @@
+###
+### Generate GDB commands, that load symbols for specified module,
+### with proper section relocations. See .gdbinit
+###
+### $Id: gmodule.pl,v 1.2 2006/05/14 11:38:42 lkundrak Exp lkundrak $
+### Lubomir Kundrak <lkudrak@skosi.org>
+###
+
+use strict;
+
+while (<>) {
+	my ($name, %sections) = split;
+
+	print "add-symbol-file $name.module";
+
+	open (READELF, "readelf -S $name.mod |") or die;
+	while (<READELF>) {
+		/\[\s*(\d+)\]\s+(\.\S+)/ or next;
+
+		if ($2 eq '.text') {
+			print " $sections{$1}";
+			next;
+		}
+
+		print " -s $2 $sections{$1}"
+			if ($sections{$1} ne '0x0');
+	};
+	close (READELF);
+	print "\n";
+}