[PATCH v4 11/15] gdb: Allow user defined "onload_<modname>" command to be run when module is loaded

[Glenn Washburn <development@efficientek.com>]

When debugging a module it can be desirable to set break points on code
in the module. This is difficult in GRUB because, at GDB start, the
module is not loaded and on EFI platforms its not known ahead of time
where the module will be loaded. So allow users to create an
"onload_<modname>" command which will be run when the module with name
"modname" is loaded.

Create new command "is_user_command" which sets $ret to true value if
the first argument is the name of a user-defined command.

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/gdb_grub.in | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/grub-core/gdb_grub.in b/grub-core/gdb_grub.in
index a0c6b1ae07..8ae6344edf 100644
--- a/grub-core/gdb_grub.in
+++ b/grub-core/gdb_grub.in
@@ -9,6 +9,20 @@
 ### Lubomir Kundrak <lkudrak@skosi.org>
 ###
 
+define is_user_command
+	eval "pipe help user-defined | grep -q '%s'", $arg0
+	set $ret = ! $_shell_exitcode
+end
+document is_user_command
+	Set $ret to true value if first argument is the name of a user-defined
+	command.
+end
+
+define is_onload_command
+	eval "set $is_onload_command_name = \"onload_%s\"", $arg0
+	is_user_command $is_onload_command_name
+end
+
 define dynamic_load_kernel_exec_symbols
 	shell rm -f .remove-kernel.exec.symfile.gdb
 	shell sh gdb_helper.sh gen_kernel_exec_loadsym $arg0 >.kernel.exec.loadsym.gdb
@@ -76,8 +90,18 @@ end
 ###
 
 define load_module
+	set $load_module_onload_cmd = ""
+	is_onload_command $arg0->name
+	if $ret
+		eval "set $load_module_onload_cmd = \"onload_%s (grub_dl_t)%p\"", $arg0->name, $arg0
+	end
+
 	dump_module_sections $arg0
 	match_and_load_symbols
+
+	if ! $_streq($load_module_onload_cmd, "")
+		eval "%s", $load_module_onload_cmd
+	end
 end
 document load_module
 	Load debugging information for module given as argument.
-- 
2.34.1