"return" command for GRUB script functions.

* tests/grub_script_return.in: New test.
	* Makefile.util.def: Rules for new test.

	* grub-core/script/execute.c (grub_script_return): New function.
	* grub-core/script/main.c: Register/unregister return commaond.
	* include/grub/script_sh.h (grub_script_return): New prototype.

ChangeLog

@@ -1,3 +1,14 @@
+2010-09-04  BVK Chaitanya  <bvk.groups@gmail.com>
+
+	"return" command for GRUB script functions.
+
+	* tests/grub_script_return.in: New test.
+	* Makefile.util.def: Rules for new test.
+
+	* grub-core/script/execute.c (grub_script_return): New function.
+	* grub-core/script/main.c: Register/unregister return commaond.
+	* include/grub/script_sh.h (grub_script_return): New prototype.
+
 2010-09-04  BVK Chaitanya  <bvk.groups@gmail.com>
 
 	"setparams" command to update positional parameters.

Makefile.util.def

@@ -513,6 +513,12 @@ script = {
   common = tests/grub_script_setparams.in;
 };
 
+script = {
+  testcase;
+  name = grub_script_return;
+  common = tests/grub_script_return.in;
+};
+
 program = {
   testcase;
   name = example_unit_test;

grub-core/script/execute.c

@@ -34,6 +34,7 @@
 static unsigned long is_continue;
 static unsigned long active_loops;
 static unsigned long active_breaks;
+static unsigned long function_return;
 
 #define GRUB_SCRIPT_SCOPE_MALLOCED      1
 #define GRUB_SCRIPT_SCOPE_ARGS_MALLOCED 2
@@ -143,6 +144,30 @@ grub_script_setparams (grub_command_t cmd __attribute__((unused)),
   return GRUB_ERR_NONE;
 }
 
+grub_err_t
+grub_script_return (grub_command_t cmd __attribute__((unused)),
+		    int argc, char *argv[])
+{
+  char *p;
+  unsigned long n;
+
+  if (! scope || argc > 1)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, "not in function scope");
+
+  if (argc == 0)
+    {
+      function_return = 1;
+      return grub_strtoul (grub_env_get ("?"), NULL, 10);
+    }
+
+  n = grub_strtoul (argv[0], &p, 10);
+  if (*p != '\0')
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, "bad argument");
+
+  function_return = 1;
+  return n ? grub_error (GRUB_ERR_TEST_FAILURE, "false") : GRUB_ERR_NONE;
+}
+
 static int
 grub_env_special (const char *name)
 {
@@ -370,6 +395,7 @@ grub_script_function_call (grub_script_function_t func, int argc, char **args)
 
   ret = grub_script_execute (func->func);
 
+  function_return = 0;
   active_loops = loops;
   replace_scope (old_scope); /* free any scopes by setparams */
   return ret;
@@ -462,8 +488,16 @@ grub_script_execute_cmdlist (struct grub_script_cmd *list)
   struct grub_script_cmd *cmd;
 
   /* Loop over every command and execute it.  */
-  for (cmd = list->next; cmd && ! active_breaks; cmd = cmd->next)
-    ret = grub_script_execute_cmd (cmd);
+  for (cmd = list->next; cmd; cmd = cmd->next)
+    {
+      if (active_breaks)
+	break;
+
+      ret = grub_script_execute_cmd (cmd);
+
+      if (function_return)
+	break;
+    }
 
   return ret;
 }
@@ -472,14 +506,17 @@ grub_script_execute_cmdlist (struct grub_script_cmd *list)
 grub_err_t
 grub_script_execute_cmdif (struct grub_script_cmd *cmd)
 {
-  struct grub_script_cmdif *cmdif = (struct grub_script_cmdif *) cmd;
+  int ret;
   char *result;
+  struct grub_script_cmdif *cmdif = (struct grub_script_cmdif *) cmd;
 
   /* Check if the commands results in a true or a false.  The value is
      read from the env variable `?'.  */
-  grub_script_execute_cmd (cmdif->exec_to_evaluate);
-  result = grub_env_get ("?");
+  ret = grub_script_execute_cmd (cmdif->exec_to_evaluate);
+  if (function_return)
+    return ret;
 
+  result = grub_env_get ("?");
   grub_errno = GRUB_ERR_NONE;
 
   /* Execute the `if' or the `else' part depending on the value of
@@ -513,6 +550,8 @@ grub_script_execute_cmdfor (struct grub_script_cmd *cmd)
 	{
 	  grub_script_env_set (cmdfor->name->str, argv.args[i]);
 	  result = grub_script_execute_cmd (cmdfor->list);
+	  if (function_return)
+	    break;
 	}
     }
 
@@ -528,18 +567,21 @@ grub_script_execute_cmdfor (struct grub_script_cmd *cmd)
 grub_err_t
 grub_script_execute_cmdwhile (struct grub_script_cmd *cmd)
 {
-  int cond;
   int result;
   struct grub_script_cmdwhile *cmdwhile = (struct grub_script_cmdwhile *) cmd;
 
   active_loops++;
-  result = 0;
   do {
-    cond = grub_script_execute_cmd (cmdwhile->cond);
-    if (cmdwhile->until ? !cond : cond)
+    result = grub_script_execute_cmd (cmdwhile->cond);
+    if (function_return)
+      break;
+
+    if (cmdwhile->until ? !result : result)
       break;
 
     result = grub_script_execute_cmd (cmdwhile->list);
+    if (function_return)
+      break;
 
     if (active_breaks == 1 && is_continue)
       active_breaks = 0;

grub-core/script/main.c

@@ -45,6 +45,7 @@ static grub_command_t cmd_break;
 static grub_command_t cmd_continue;
 static grub_command_t cmd_shift;
 static grub_command_t cmd_setparams;
+static grub_command_t cmd_return;
 
 void
 grub_script_init (void)
@@ -58,6 +59,8 @@ grub_script_init (void)
   cmd_setparams = grub_register_command ("setparams", grub_script_setparams,
 					 N_("[VALUE]..."),
 					 N_("Set positional parameters."));
+  cmd_return = grub_register_command ("return", grub_script_return,
+				      N_("[n]"), N_("Return from a function."));
 }
 
 void
@@ -78,4 +81,8 @@ grub_script_fini (void)
   if (cmd_setparams)
     grub_unregister_command (cmd_setparams);
   cmd_setparams = 0;
+
+  if (cmd_return)
+    grub_unregister_command (cmd_return);
+  cmd_return = 0;
 }

include/grub/script_sh.h

@@ -346,6 +346,9 @@ grub_err_t grub_script_shift (grub_command_t cmd, int argc, char *argv[]);
 /* SETPARAMS command for GRUB script functions.  */
 grub_err_t grub_script_setparams (grub_command_t cmd, int argc, char *argv[]);
 
+/* RETURN command for functions.  */
+grub_err_t grub_script_return (grub_command_t cmd, int argc, char *argv[]);
+
 /* This variable points to the parsed command.  This is used to
    communicate with the bison code.  */
 extern struct grub_script_cmd *grub_script_parsed;

tests/grub_script_return.in

@@ -0,0 +1,134 @@
+#! @builddir@/grub-shell-tester
+
+# Run GRUB script in a Qemu instance
+# Copyright (C) 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/>.
+
+function f1 {
+    return
+    echo one
+}
+f1
+
+function f2 {
+    true
+    return
+    echo one
+}
+if f2; then echo true; else echo false; fi
+
+function f3 {
+    false
+    return
+    echo one
+}
+if f3; then echo true; else echo false; fi
+
+function f4 {
+    true
+    return 1;
+    echo one
+}
+if f4; then echo true; else echo false; fi
+
+function f5 {
+    false
+    return 0;
+    echo one
+}
+if f5; then echo true; else echo false; fi
+
+function f6 {
+    echo one
+    if true; then
+	echo two
+	return 0
+    else
+	echo three
+	return 1
+    fi
+    echo four
+}
+if f6; then echo true; else echo false; fi
+
+function f7 {
+    if return 1; then
+	echo one
+    else
+	echo no
+    fi
+}
+if f7; then echo true; else echo false; fi
+
+function f8 {
+    echo one
+    for v in 1 2 3 4 5; do
+	echo $v
+	if test $v = 3; then return 1; fi
+    done
+    echo two
+}
+if f8; then echo true; else echo false; fi
+
+function f9 {
+    x=1
+    echo one
+    until test x = 11111111; do
+	echo $x
+	x="1$x"
+	if test $x = 1111; then return 0; fi
+    done
+    echo two
+}
+if f9; then echo true; else echo false; fi
+
+function f10 {
+    echo one
+    while return 0; do
+	echo two
+    done
+    echo three
+}
+if f10; then echo true; else echo false; fi
+
+function f11 {
+    f1
+    f2
+    f3
+    f4
+    f5
+    f6
+    f7
+    f8
+    f9
+    f10
+}
+if f11; then echo true; else echo false; fi
+
+function f12 {
+    echo one
+    f11
+    return 1
+    echo two
+}
+if f12; then echo true; else echo false; fi
+
+function f13 {
+    echo one
+    f12
+    echo two
+    return 0
+}
+if f13; then echo true; else echo false; fi