Re: RFC: Plan for new "hwmatch" command

[Colin Watson <cjwatson@ubuntu.com>]

On Wed, Nov 17, 2010 at 08:58:43PM -0800, Evan Broder wrote:
>    Based on some off-list discussion, I'd like to try a different
> angle for the Lua patches I submitted a week or two ago. For context,
> Ubuntu is interested in setting gfxpayload=keep as often as we can in
> the next release [1]. Since gfxpayload=keep doesn't work with all
> hardware/driver combinations, we need a way to selectively turn it on,
> based on a whitelist or blacklist.

This is an implementation of Evan's original proposal in C.  I realise
that there was feedback on the list
(http://lists.gnu.org/archive/html/grub-devel/2010-11/msg00038.html)
that I haven't incorporated; my initial priority was solely to avoid
needing to ship the Lua grub-extras module in Ubuntu 11.04, since we had
feedback from Robert Millan among others that this would be undesirable.

I rather expect that any upstreamable implementation of this would want
to be built on more than just i386_pc, too.

But in case anyone is interested in using this as a starting point:

=== modified file 'grub-core/Makefile.core.def'
--- grub-core/Makefile.core.def	2011-03-26 11:59:02 +0000
+++ grub-core/Makefile.core.def	2011-03-29 15:10:11 +0000
@@ -595,6 +595,15 @@ module = {
 };
 
 module = {
+  name = hwmatch;
+  i386_pc = commands/i386/pc/hwmatch.c;
+  enable = i386_pc;
+  ldadd = libgnulib.a;
+  cflags = '$(CFLAGS_POSIX) $(CFLAGS_GNULIB)';
+  cppflags = '$(CPPFLAGS_POSIX) $(CPPFLAGS_GNULIB)';
+};
+
+module = {
   name = keystatus;
   common = commands/keystatus.c;
 };

=== added file 'grub-core/commands/i386/pc/hwmatch.c'
--- grub-core/commands/i386/pc/hwmatch.c	1970-01-01 00:00:00 +0000
+++ grub-core/commands/i386/pc/hwmatch.c	2011-03-29 20:29:07 +0000
@@ -0,0 +1,139 @@
+/* hwmatch.c - Match hardware against a whitelist/blacklist.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2011  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/>.
+ */
+
+#include <grub/dl.h>
+#include <grub/misc.h>
+#include <grub/command.h>
+#include <grub/pci.h>
+#include <grub/normal.h>
+#include <grub/file.h>
+#include <grub/env.h>
+#include <grub/i18n.h>
+#include <regex.h>
+
+static grub_err_t
+grub_cmd_hwmatch (grub_command_t cmd __attribute__ ((unused)),
+		  int argc, char **args)
+{
+  grub_file_t matches_file;
+  int class_match;
+  int match = 0;
+  char *match_str;
+
+  auto int NESTED_FUNC_ATTR hwmatch_iter (grub_pci_device_t dev,
+					  grub_pci_id_t pciid);
+
+  int NESTED_FUNC_ATTR hwmatch_iter (grub_pci_device_t dev,
+				     grub_pci_id_t pciid)
+  {
+    grub_pci_address_t addr;
+    grub_uint32_t class, baseclass, vendor, device;
+    grub_pci_id_t subpciid;
+    grub_uint32_t subvendor, subdevice, subclass;
+    char *id, *line;
+
+    addr = grub_pci_make_address (dev, GRUB_PCI_REG_CLASS);
+    class = grub_pci_read (addr);
+    baseclass = class >> 24;
+
+    if (class_match != baseclass)
+      return 0;
+
+    vendor = pciid & 0xffff;
+    device = pciid >> 16;
+
+    addr = grub_pci_make_address (dev, GRUB_PCI_REG_SUBVENDOR);
+    subpciid = grub_pci_read (addr);
+
+    subclass = (class >> 16) & 0xff;
+    subvendor = subpciid & 0xffff;
+    subdevice = subpciid >> 16;
+
+    id = grub_xasprintf ("v%04xd%04xsv%04xsd%04xbc%02xsc%02x",
+			 vendor, device, subvendor, subdevice,
+			 baseclass, subclass);
+
+    grub_file_seek (matches_file, 0);
+    while ((line = grub_file_getline (matches_file)) != NULL)
+      {
+	char *anchored_line;
+	regex_t regex;
+	int ret;
+
+	if (! *line || *line == '#')
+	  {
+	    grub_free (line);
+	    continue;
+	  }
+
+	anchored_line = grub_xasprintf ("^%s$", line);
+	ret = regcomp (&regex, anchored_line, REG_EXTENDED | REG_NOSUB);
+	grub_free (anchored_line);
+	if (ret)
+	  {
+	    grub_free (line);
+	    continue;
+	  }
+
+	ret = regexec (&regex, id, 0, NULL, 0);
+	regfree (&regex);
+	grub_free (line);
+	if (! ret)
+	  {
+	    match = 1;
+	    return 1;
+	  }
+      }
+
+    return 0;
+  }
+
+  if (argc < 2)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, "list file and class required");
+
+  matches_file = grub_file_open (args[0]);
+  if (! matches_file)
+    return grub_error (GRUB_ERR_FILE_NOT_FOUND, "file not found");
+
+  class_match = grub_strtol (args[1], 0, 10);
+
+  grub_pci_iterate (hwmatch_iter);
+
+  match_str = grub_xasprintf ("%d", match);
+  grub_env_set ("match", match_str);
+  grub_free (match_str);
+
+  grub_file_close (matches_file);
+
+  return GRUB_ERR_NONE;
+}
+
+static grub_command_t cmd;
+\f
+GRUB_MOD_INIT(hwmatch)
+{
+  cmd = grub_register_command ("hwmatch", grub_cmd_hwmatch,
+			       N_("MATCHES-FILE CLASS"),
+			       N_("Match PCI devices."));
+}
+
+GRUB_MOD_FINI(hwmatch)
+{
+  grub_unregister_command (cmd);
+}

-- 
Colin Watson                                       [cjwatson@ubuntu.com]