gdb: Fix redirection issue in dump_module_sections

An error in any GDB command causes it to immediately abort with an error,
this includes any command that calls that command. This leads to an issue
in dump_module_sections where an error causes the command to exit without
turning off file redirection. The user then ends up with a GDB command
line where commands output nothing to the console.

Instead do the work of dump_module_sections in the command
dump_module_sections_helper and run the command using GDB's pipe command
which does the redirection and undoes the redirection when it finishes
regardless of any errors in the command.

Also, remove .segments.tmp file prior to loading modules in case one was
left from a previous run.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/gdb_grub.in

@@ -10,15 +10,8 @@
 ###
 
 # Add section numbers and addresses to .segments.tmp
-define dump_module_sections
+define dump_module_sections_helper
 	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)
@@ -26,9 +19,10 @@ define dump_module_sections
 		set $segment = $segment->next
 	end
 	printf "\n"
+end
 
-	set logging off
+define dump_module_sections
-	# FIXME: restore logging status
+	pipe dump_module_sections_helper $arg0 | sh -c 'cat >>.segments.tmp'
 end
 document dump_module_sections
 	Gather information about module whose mod structure was
@@ -59,6 +53,7 @@ document load_module
 end
 
 define load_all_modules
+	shell rm -f .segments.tmp
 	set $this = grub_dl_head
 	while ($this != 0)
 		dump_module_sections $this