Added new commands to add and subtract values from grub variables, was desirable for automated testing. Compiled and tested under x86_64-efi.
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 474a63e68..c383f0157 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -2503,3 +2503,8 @@ module = {
common = commands/i386/wrmsr.c;
enable = x86;
};
+
+module = {
+ name = basic_math;
+ common = commands/basic_math.c;
+};
diff --git a/grub-core/commands/basic_math.c b/grub-core/commands/basic_math.c
new file mode 100644
index 000000000..9337cd5b1
--- /dev/null
+++ b/grub-core/commands/basic_math.c
@@ -0,0 +1,134 @@
+/* basic_math.c - basic math functions. */
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2008,2009,2010 Free Software Foundation, Inc.
+ *
+ * GRUB 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* what any module needs */
+#include <grub/dl.h>
+#include <grub/misc.h>
+#include <grub/extcmd.h>
+#include <grub/i18n.h>
+#include <grub/mm.h>
+/* what my module needs */
+#include <grub/env.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_err_t
+grub_cmd_add (grub_extcmd_context_t ctxt __attribute__ ((unused)), int argc, char **args)
+{
+ unsigned int i;
+ int ret, value_int=0, arg_int=0, digit;
+ const char *value;
+ char buf[512];
+
+ if (argc != 2)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Variable and value required"));
+
+ value = grub_env_get (args[0]);
+ if (!value)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Variable must be defined"));
+
+ for (i=0;i<grub_strlen(value);i++) {
+ if (grub_isdigit((int)value[i])) {
+ digit = value[i] - '0';
+ value_int = (10*value_int) + digit;
+ }
+ }
+
+ for (i=0;i<grub_strlen(args[1]);i++) {
+ if (grub_isdigit((int)args[1][i])) {
+ digit = args[1][i] - '0';
+ arg_int = (10*arg_int) + digit;
+ } else {
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Value must be a positive interger"));
+ }
+ }
+
+ ret=value_int+arg_int;
+ /* grub_printf ("%d\n", ret); */
+
+ grub_snprintf (buf, sizeof (buf), "%d", ret);
+ /* grub_printf ("%s\n", buf); */
+ grub_env_set (args[0], buf);
+ return 0;
+}
+
+static grub_err_t
+grub_cmd_sub (grub_extcmd_context_t ctxt __attribute__ ((unused)), int argc, char **args)
+{
+ unsigned int i;
+ int ret, value_int=0, arg_int=0, digit;
+ const char *value;
+ char buf[512];
+
+ if (argc != 2)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Variable and value required"));
+
+ value = grub_env_get (args[0]);
+ if (!value)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Variable must be defined"));
+
+ for (i=0;i<grub_strlen(value);i++) {
+ if (grub_isdigit((int)value[i])) {
+ digit = value[i] - '0';
+ value_int = (10*value_int) + digit;
+ }
+ }
+
+ for (i=0;i<grub_strlen(args[1]);i++) {
+ if (grub_isdigit((int)args[1][i])) {
+ digit = args[1][i] - '0';
+ arg_int = (10*arg_int) + digit;
+ } else {
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Value must be a positive interger"));
+ }
+ }
+
+ if (arg_int > value_int)
+ return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("Result may not be negitive"));
+
+ ret=value_int-arg_int;
+ /* grub_printf ("%d\n", ret); */
+
+ grub_snprintf (buf, sizeof (buf), "%d", ret);
+ /* grub_printf ("%s\n", buf); */
+ grub_env_set (args[0], buf);
+ return 0;
+}
+
+static grub_extcmd_t cmd_add, cmd_sub;
+
+GRUB_MOD_INIT(basic_math)
+{
+ cmd_add =
+ grub_register_extcmd ("add", grub_cmd_add, 0,
+ N_("<variable_name> <value>"),
+ N_("Add value to variable."),
+ 0);
+ cmd_sub =
+ grub_register_extcmd ("sub", grub_cmd_sub, 0,
+ N_("<variable_name> <value>"),
+ N_("Subtract value from variable."),
+ 0);
+}
+
+GRUB_MOD_FINI(basic_math)
+{
+ grub_unregister_extcmd (cmd_add);
+ grub_unregister_extcmd (cmd_sub);
+}
_______________________________________________