Support for updating environment variables with matched substrings

of regexp.

	* tests/grub_cmd_regexp.in: New test.
	* Makefile.util.def: Rule for new test.

	* grub-core/commands/regexp.c: New option -s to update environment
	variables with regexp matches.

ChangeLog

@@ -1,3 +1,14 @@
+2010-09-04  BVK Chaitanya  <bvk.groups@gmail.com>
+
+	Support for updating environment variables with matched substrings
+	of regexp.
+
+	* tests/grub_cmd_regexp.in: New test.
+	* Makefile.util.def: Rule for new test.
+
+	* grub-core/commands/regexp.c: New option -s to update environment
+	variables with regexp matches.
+
 2010-09-04  Szymon Janc <szymon@janc.net.pl>
 
 	* include/grub/file.h (grub_file): New member not_easly_seekable.

Makefile.util.def

@@ -519,6 +519,12 @@ script = {
   common = tests/grub_script_return.in;
 };
 
+script = {
+  testcase;
+  name = grub_cmd_regexp;
+  common = tests/grub_cmd_regexp.in;
+};
+
 program = {
   testcase;
   name = example_unit_test;

grub-core/commands/regexp.c

@@ -20,37 +20,103 @@
 #include <grub/dl.h>
 #include <grub/misc.h>
 #include <grub/mm.h>
-#include <grub/command.h>
+#include <grub/err.h>
+#include <grub/env.h>
+#include <grub/extcmd.h>
 #include <grub/i18n.h>
 #include <regex.h>
 
+static const struct grub_arg_option options[] =
+  {
+    { "set", 's', GRUB_ARG_OPTION_REPEATABLE,
+      N_("Variable names to update with matches."),
+      N_("[NUMBER:]VARNAME"), ARG_TYPE_STRING },
+    { 0, 0, 0, 0, 0, 0 }
+  };
+
 static grub_err_t
-grub_cmd_regexp (grub_command_t cmd __attribute__ ((unused)),
-		 int argc, char **args)
+set_matches (char **varnames, char *str, grub_size_t nmatches,
+	     regmatch_t *matches)
+{
+  int i;
+  char ch;
+  char *p;
+  char *q;
+  grub_err_t err;
+  unsigned long j;
+
+  auto void setvar (char *v, regmatch_t *m);
+  void setvar (char *v, regmatch_t *m)
+  {
+    ch = str[m->rm_eo];
+    str[m->rm_eo] = '\0';
+    err = grub_env_set (v, str + m->rm_so);
+    str[m->rm_eo] = ch;
+  }
+
+  for (i = 0; varnames && varnames[i]; i++)
+    {
+      if (! (p = grub_strchr (varnames[i], ':')))
+	{
+	  /* varname w/o index defaults to 1 */
+	  if (nmatches < 2 || matches[1].rm_so == -1)
+	    grub_env_unset (varnames[i]);
+	  else
+	    setvar (varnames[i], &matches[1]);
+	}
+      else
+	{
+	  j = grub_strtoul (varnames[i], &q, 10);
+	  if (q != p)
+	    return grub_error (GRUB_ERR_BAD_ARGUMENT,
+			       "invalid variable name format %s", varnames[i]);
+
+	  if (nmatches <= j || matches[j].rm_so == -1)
+	    grub_env_unset (p + 1);
+	  else
+	    setvar (p + 1, &matches[j]);
+	}
+
+      if (err != GRUB_ERR_NONE)
+	return err;
+    }
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_regexp (grub_extcmd_context_t ctxt, int argc, char **args)
 {
   int argn = 0;
-  int matches = 0;
   regex_t regex;
   int ret;
   grub_size_t s;
   char *comperr;
   grub_err_t err;
+  regmatch_t *matches = 0;
 
   if (argc != 2)
     return grub_error (GRUB_ERR_BAD_ARGUMENT, "2 arguments expected");
 
-  ret = regcomp (&regex, args[0], RE_SYNTAX_GNU_AWK);
+  ret = regcomp (&regex, args[0], REG_EXTENDED);
   if (ret)
     goto fail;
 
-  ret = regexec (&regex, args[1], 0, 0, 0);
+  matches = grub_zalloc (sizeof (*matches) * (regex.re_nsub + 1));
+  if (! matches)
+    goto fail;
+
+  ret = regexec (&regex, args[1], regex.re_nsub + 1, matches, 0);
   if (!ret)
     {
+      err = set_matches (ctxt->state[0].args, args[1],
+			 regex.re_nsub + 1, matches);
       regfree (&regex);
-      return GRUB_ERR_NONE;
+      grub_free (matches);
+      return err;
     }
 
  fail:
+  grub_free (matches);
   s = regerror (ret, &regex, 0, 0);
   comperr = grub_malloc (s);
   if (!comperr)
@@ -65,16 +131,16 @@ grub_cmd_regexp (grub_command_t cmd __attribute__ ((unused)),
   return err;
 }
 
-static grub_command_t cmd;
+static grub_extcmd_t cmd;
 
 GRUB_MOD_INIT(regexp)
 {
-  cmd = grub_register_command ("regexp", grub_cmd_regexp,
-			       N_("REGEXP STRING"),
-			       N_("Test if REGEXP matches STRING."));
+  cmd = grub_register_extcmd ("regexp", grub_cmd_regexp,
+			      GRUB_COMMAND_FLAG_BOTH, N_("REGEXP STRING"),
+			      N_("Test if REGEXP matches STRING."), options);
 }
 
 GRUB_MOD_FINI(regexp)
 {
-  grub_unregister_command (cmd);
+  grub_unregister_extcmd (cmd);
 }

tests/grub_cmd_regexp.in

@@ -0,0 +1,41 @@
+#! /bin/bash -e
+
+# 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/>.
+
+cmd='regexp -s version "vm-(.*)" vm-1.2.3; echo $version'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test "$v" != 1.2.3; then echo "error: $cmd" >&2; exit 1; fi
+
+cmd='regexp -s 1:version "vm-(.*)" vm-1.2.3; echo $version'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test "$v" != 1.2.3; then echo "error: $cmd" >&2; exit 1; fi
+
+cmd='regexp -s 0:match "vm-(.*)" vm-1.2.3; echo $match'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test "$v" != vm-1.2.3; then echo "error: $cmd" >&2; exit 1; fi
+
+cmd='regexp -s 2:match "vm-(.*)" vm-1.2.3; echo $match'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test -n "$v"; then echo "error: $cmd" >&2; exit 1; fi
+
+cmd='regexp -s match "\\\((.*)\\\)" (hd0,msdos1); echo $match'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test "$v" != "hd0,msdos1"; then echo "error: $cmd" >&2; exit 1; fi
+
+cmd='regexp -s match "hd([0-9]+)" hd0; echo $match'
+v=`echo "$cmd" | @builddir@/grub-shell`
+if test "$v" != "0"; then echo "error: $cmd" >&2; exit 1; fi