gnu: grub: Allow "grub-bios-setup" to operate on raw disk-images.

* gnu/packages/patches/grub-setup-root.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/bootloaders.scm (grub): Apply it.

gnu/local.mk

@@ -1041,6 +1041,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/gromacs-tinyxml2.patch			\
   %D%/packages/patches/groovy-add-exceptionutilsgenerator.patch	\
   %D%/packages/patches/grub-efi-fat-serial-number.patch		\
+  %D%/packages/patches/grub-setup-root.patch			\
   %D%/packages/patches/grub-verifiers-Blocklist-fallout-cleanup.patch \
   %D%/packages/patches/gspell-dash-test.patch			\
   %D%/packages/patches/guile-1.8-cpp-4.5.patch			\

gnu/packages/bootloaders.scm

@@ -96,6 +96,7 @@
                "0zgp5m3hmc9jh8wpjx6czzkh5id2y8n1k823x2mjvm2sk6b28ag5"))
              (patches (search-patches
                        "grub-efi-fat-serial-number.patch"
+                       "grub-setup-root.patch"
                        "grub-verifiers-Blocklist-fallout-cleanup.patch"))))
     (build-system gnu-build-system)
     (arguments

gnu/packages/patches/grub-setup-root.patch

@@ -0,0 +1,124 @@
+This patch is taken from OpenWrt, see:
+
+https://github.com/openwrt/openwrt/blob/master/package/boot/grub2/patches/100-grub_setup_root.patch.
+
+It allows to use grub-bios-setup on a raw disk-images, without root permissions.
+
+--- a/util/grub-setup.c
++++ b/util/grub-setup.c
+@@ -87,6 +87,8 @@ static struct argp_option options[] = {
+    N_("install even if problems are detected"), 0},
+   {"skip-fs-probe",'s',0,      0,
+    N_("do not probe for filesystems in DEVICE"), 0},
++  {"root-device", 'r', N_("DEVICE"), 0,
++   N_("use DEVICE as the root device"), 0},
+   {"verbose",     'v', 0,      0, N_("print verbose messages."), 0},
+   {"allow-floppy", 'a', 0,      0,
+    /* TRANSLATORS: The potential breakage isn't limited to floppies but it's
+@@ -130,6 +132,7 @@ struct arguments
+   char *core_file;
+   char *dir;
+   char *dev_map;
++  char *root_dev;
+   int  force;
+   int  fs_probe;
+   int allow_floppy;
+@@ -178,6 +181,13 @@ argp_parser (int key, char *arg, struct
+         arguments->dev_map = xstrdup (arg);
+         break;
+ 
++      case 'r':
++        if (arguments->root_dev)
++          free (arguments->root_dev);
++
++        arguments->root_dev = xstrdup (arg);
++        break;
++
+       case 'f':
+         arguments->force = 1;
+         break;
+@@ -313,7 +323,7 @@ main (int argc, char *argv[])
+   GRUB_SETUP_FUNC (arguments.dir ? : DEFAULT_DIRECTORY,
+ 		   arguments.boot_file ? : DEFAULT_BOOT_FILE,
+ 		   arguments.core_file ? : DEFAULT_CORE_FILE,
+-		   dest_dev, arguments.force,
++		   arguments.root_dev, dest_dev, arguments.force,
+ 		   arguments.fs_probe, arguments.allow_floppy,
+ 		   arguments.add_rs_codes);
+ 
+--- a/util/setup.c
++++ b/util/setup.c
+@@ -252,13 +252,12 @@ identify_partmap (grub_disk_t disk __att
+ void
+ SETUP (const char *dir,
+        const char *boot_file, const char *core_file,
+-       const char *dest, int force,
++       char *root, const char *dest, int force,
+        int fs_probe, int allow_floppy,
+        int add_rs_codes __attribute__ ((unused))) /* unused on sparc64 */
+ {
+   char *core_path;
+   char *boot_img, *core_img, *boot_path;
+-  char *root = 0;
+   size_t boot_size, core_size;
+   grub_uint16_t core_sectors;
+   grub_device_t root_dev = 0, dest_dev, core_dev;
+@@ -307,7 +306,10 @@ SETUP (const char *dir,
+ 
+   core_dev = dest_dev;
+ 
+-  {
++  if (root)
++    root_dev = grub_device_open(root);
++
++  if (!root_dev) {
+     char **root_devices = grub_guess_root_devices (dir);
+     char **cur;
+     int found = 0;
+@@ -320,6 +322,8 @@ SETUP (const char *dir,
+ 	char *drive;
+ 	grub_device_t try_dev;
+ 
++	if (root_dev)
++	  break;
+ 	drive = grub_util_get_grub_dev (*cur);
+ 	if (!drive)
+ 	  continue;
+--- a/include/grub/util/install.h
++++ b/include/grub/util/install.h
+@@ -191,13 +191,13 @@ grub_install_get_image_target (const cha
+ void
+ grub_util_bios_setup (const char *dir,
+ 		      const char *boot_file, const char *core_file,
+-		      const char *dest, int force,
++		      char *root, const char *dest, int force,
+ 		      int fs_probe, int allow_floppy,
+ 		      int add_rs_codes);
+ void
+ grub_util_sparc_setup (const char *dir,
+ 		       const char *boot_file, const char *core_file,
+-		       const char *dest, int force,
++		       char *root, const char *dest, int force,
+ 		       int fs_probe, int allow_floppy,
+ 		       int add_rs_codes);
+ 
+--- a/util/grub-install.c
++++ b/util/grub-install.c
+@@ -1712,7 +1712,7 @@ main (int argc, char *argv[])
+ 	/*  Now perform the installation.  */
+ 	if (install_bootsector)
+ 	  grub_util_bios_setup (platdir, "boot.img", "core.img",
+-				install_drive, force,
++				NULL, install_drive, force,
+ 				fs_probe, allow_floppy, add_rs_codes);
+ 	break;
+       }
+@@ -1738,7 +1738,7 @@ main (int argc, char *argv[])
+ 	/*  Now perform the installation.  */
+ 	if (install_bootsector)
+ 	  grub_util_sparc_setup (platdir, "boot.img", "core.img",
+-				 install_drive, force,
++				 NULL, install_drive, force,
+ 				 fs_probe, allow_floppy,
+ 				 0 /* unused */ );
+ 	break;