grub2/0414-blsuki-Check-for-mounted-boot-in-emu.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Robbie Harwood <rharwood@redhat.com>
Date: Tue, 12 Aug 2025 03:45:35 +0000
Subject: [PATCH] blsuki: Check for mounted /boot in emu

Irritatingly, BLS defines paths relative to the mountpoint of the
filesystem which contains its snippets, not / or any other fixed
location. So grub-emu needs to know whether /boot is a separate
filesystem from / and conditionally prepend a path.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/Makefile.core.def     |  3 ++
 grub-core/commands/blsuki.c     | 83 +++++++++++++++++++++++++++++++++++++----
 grub-core/osdep/linux/getroot.c |  8 ++++
 grub-core/osdep/unix/getroot.c  |  4 +-
 include/grub/emu/misc.h         |  2 +-
 5 files changed, 91 insertions(+), 9 deletions(-)

diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 78fafdd8fa..ddc5e71bbb 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -378,6 +378,9 @@ kernel = {
   emu = kern/emu/cache_s.S;
   emu = kern/emu/hostdisk.c;
   emu = osdep/unix/hostdisk.c;
+  emu = osdep/relpath.c;
+  emu = osdep/getroot.c;
+  emu = osdep/unix/getroot.c;
   emu = osdep/exec.c;
   extra_dist = osdep/unix/exec.c;
   emu = osdep/devmapper/hostdisk.c;
diff --git a/grub-core/commands/blsuki.c b/grub-core/commands/blsuki.c
index 9440adb100..ed93a150b1 100644
--- a/grub-core/commands/blsuki.c
+++ b/grub-core/commands/blsuki.c
@@ -32,6 +32,13 @@
 #include <grub/lib/envblk.h>
 #include <filevercmp.h>
 
+#ifdef GRUB_MACHINE_EMU
+#include <grub/emu/misc.h>
+#define GRUB_BOOT_DEVICE "/boot"
+#else
+#define GRUB_BOOT_DEVICE ""
+#endif
+
 GRUB_MOD_LICENSE ("GPLv3+");
 
 #define GRUB_BLS_CONFIG_PATH "/loader/entries/"
@@ -79,6 +86,34 @@ static grub_blsuki_entry_t *entries;
 
 #define FOR_BLSUKI_ENTRIES(var) FOR_LIST_ELEMENTS (var, entries)
 
+/*
+ * BLS appears to make paths relative to the filesystem that snippets are
+ * on, not /. Attempt to cope.
+ */
+static char *blsuki_update_boot_device (char *tmp)
+{
+#ifdef GRUB_MACHINE_EMU
+  static int separate_boot = -1;
+  char *ret;
+
+  if (separate_boot != -1)
+    goto probed;
+
+  separate_boot = 0;
+
+  ret = grub_make_system_path_relative_to_its_root (GRUB_BOOT_DEVICE);
+
+  if (ret != NULL && ret[0] == '\0')
+    separate_boot = 1;
+
+ probed:
+  if (separate_boot == 0)
+    return tmp;
+#endif
+
+  return grub_stpcpy (tmp, GRUB_BOOT_DEVICE);
+}
+
 /*
  * This function will add a new keyval pair to a list of keyvals stored in the
  * entry parameter.
@@ -526,7 +561,7 @@ bls_get_linux (grub_blsuki_entry_t *entry)
   linux_path = blsuki_get_val (entry, "linux", NULL);
   options = blsuki_expand_val (blsuki_get_val (entry, "options", NULL));
 
-  if (grub_add (sizeof ("linux "), grub_strlen (linux_path), &size))
+  if (grub_add (sizeof ("linux " GRUB_BOOT_DEVICE), grub_strlen (linux_path), &size))
     {
       grub_error (GRUB_ERR_OUT_OF_RANGE, "overflow detected while calculating linux buffer size");
       goto finish;
@@ -548,6 +583,7 @@ bls_get_linux (grub_blsuki_entry_t *entry)
 
   tmp = linux_cmd;
   tmp = grub_stpcpy (tmp, "linux ");
+  tmp = blsuki_update_boot_device (tmp);
   tmp = grub_stpcpy (tmp, linux_path);
   if (options != NULL)
     {
@@ -582,7 +618,7 @@ bls_get_initrd (grub_blsuki_entry_t *entry)
 
       for (i = 0; initrd_list != NULL && initrd_list[i] != NULL; i++)
 	{
-	  if (grub_add (size, 1, &size) ||
+	  if (grub_add (size, sizeof (" " GRUB_BOOT_DEVICE) - 1, &size) ||
 	      grub_add (size, grub_strlen (initrd_list[i]), &size))
 	    {
 	      grub_error (GRUB_ERR_OUT_OF_RANGE, "overflow detected calculating initrd buffer size");
@@ -605,6 +641,7 @@ bls_get_initrd (grub_blsuki_entry_t *entry)
 	{
 	  grub_dprintf ("blsuki", "adding initrd %s\n", initrd_list[i]);
 	  tmp = grub_stpcpy (tmp, " ");
+	  tmp = blsuki_update_boot_device (tmp);
 	  tmp = grub_stpcpy (tmp, initrd_list[i]);
 	}
       tmp = grub_stpcpy (tmp, "\n");
@@ -630,7 +667,7 @@ bls_get_devicetree (grub_blsuki_entry_t *entry)
   dt_path = blsuki_expand_val (blsuki_get_val (entry, "devicetree", NULL));
   if (dt_path != NULL)
     {
-      if (grub_add (sizeof ("devicetree "), grub_strlen (dt_path), &size) ||
+      if (grub_add (sizeof ("devicetree " GRUB_BOOT_DEVICE), grub_strlen (dt_path), &size) ||
 	  grub_add (size, 1, &size))
 	{
 	  grub_error (GRUB_ERR_OUT_OF_RANGE, "overflow detected calculating device tree buffer size");
@@ -643,6 +680,7 @@ bls_get_devicetree (grub_blsuki_entry_t *entry)
 
       tmp = dt_cmd;
       tmp = grub_stpcpy (dt_cmd, "devicetree ");
+      tmp = blsuki_update_boot_device (tmp);
       tmp = grub_stpcpy (tmp, dt_path);
       tmp = grub_stpcpy (tmp, "\n");
     }
@@ -757,7 +795,11 @@ blsuki_set_find_entry_info (struct find_entry_info *info, const char *dirname, c
 
   if (devid == NULL)
     {
+#ifdef GRUB_MACHINE_EMU
+      devid = "host";
+#else
       devid = grub_env_get ("root");
+#endif
       if (devid == NULL)
 	return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("variable '%s' isn't set"), "root");
     }
@@ -799,10 +841,13 @@ blsuki_set_find_entry_info (struct find_entry_info *info, const char *dirname, c
  * parameter. If the fallback option is enabled, the default location will be
  * checked for BLS config files if the first attempt fails.
  */
-static void
+static grub_err_t
 blsuki_find_entry (struct find_entry_info *info, bool enable_fallback)
 {
   struct read_entry_info read_entry_info;
+  char *default_dir = NULL;
+  char *tmp;
+  grub_size_t default_size;
   grub_fs_t dir_fs = NULL;
   grub_device_t dir_dev = NULL;
   bool fallback = false;
@@ -833,7 +878,15 @@ blsuki_find_entry (struct find_entry_info *info, bool enable_fallback)
        */
       if (entries == NULL && fallback == false && enable_fallback == true)
 	{
-	  blsuki_set_find_entry_info (info, GRUB_BLS_CONFIG_PATH, NULL);
+	  default_size = sizeof (GRUB_BOOT_DEVICE) + sizeof (GRUB_BLS_CONFIG_PATH) - 1;
+	  default_dir = grub_malloc (default_size);
+	  if (default_dir == NULL)
+	    return grub_errno;
+
+	  tmp = blsuki_update_boot_device (default_dir);
+	  tmp = grub_stpcpy (tmp, GRUB_BLS_CONFIG_PATH);
+
+	  blsuki_set_find_entry_info (info, default_dir, NULL);
 	  grub_dprintf ("blsuki", "Entries weren't found in %s, fallback to %s\n",
 			read_entry_info.dirname, info->dirname);
 	  fallback = true;
@@ -842,6 +895,9 @@ blsuki_find_entry (struct find_entry_info *info, bool enable_fallback)
 	fallback = false;
     }
   while (fallback == true);
+
+  grub_free (default_dir);
+  return GRUB_ERR_NONE;
 }
 
 static grub_err_t
@@ -851,6 +907,9 @@ blsuki_load_entries (char *path, bool enable_fallback)
   static grub_err_t r;
   const char *devid = NULL;
   char *dir = NULL;
+  char *default_dir = NULL;
+  char *tmp;
+  grub_size_t dir_size;
   struct find_entry_info info = {
       .dev = NULL,
       .fs = NULL,
@@ -892,15 +951,25 @@ blsuki_load_entries (char *path, bool enable_fallback)
     }
 
   if (dir == NULL)
-    dir = (char *) GRUB_BLS_CONFIG_PATH;
+    {
+      dir_size = sizeof (GRUB_BOOT_DEVICE) + sizeof (GRUB_BLS_CONFIG_PATH) - 2;
+      default_dir = grub_malloc (dir_size);
+      if (default_dir == NULL)
+	return grub_errno;
+
+      tmp = blsuki_update_boot_device (default_dir);
+      tmp = grub_stpcpy (tmp, GRUB_BLS_CONFIG_PATH);
+      dir = default_dir;
+    }
 
   r = blsuki_set_find_entry_info (&info, dir, devid);
   if (r == GRUB_ERR_NONE)
-    blsuki_find_entry (&info, enable_fallback);
+    r = blsuki_find_entry (&info, enable_fallback);
 
   if (info.dev != NULL)
     grub_device_close (info.dev);
 
+  grub_free (default_dir);
   return r;
 }
 
diff --git a/grub-core/osdep/linux/getroot.c b/grub-core/osdep/linux/getroot.c
index b832593213..a60cf18a01 100644
--- a/grub-core/osdep/linux/getroot.c
+++ b/grub-core/osdep/linux/getroot.c
@@ -139,6 +139,7 @@ struct mountinfo_entry
   char fstype[ESCAPED_PATH_MAX + 1], device[ESCAPED_PATH_MAX + 1];
 };
 
+#ifdef GRUB_UTIL
 static char **
 grub_util_raid_getmembers (const char *name, int bootable)
 {
@@ -199,6 +200,7 @@ grub_util_raid_getmembers (const char *name, int bootable)
 
   return devicelist;
 }
+#endif
 
 /* Statting something on a btrfs filesystem always returns a virtual device
    major/minor pair rather than the real underlying device, because btrfs
@@ -700,6 +702,7 @@ out:
   return ret;
 }
 
+#ifdef GRUB_UTIL
 static char *
 get_mdadm_uuid (const char *os_dev)
 {
@@ -757,6 +760,7 @@ out:
 
   return name;
 }
+#endif
 
 static int
 grub_util_is_imsm (const char *os_dev)
@@ -1089,6 +1093,7 @@ grub_util_part_to_disk (const char *os_dev, struct stat *st,
   return path;
 }
 
+#ifdef GRUB_UTIL
 static char *
 grub_util_get_raid_grub_dev (const char *os_dev)
 {
@@ -1191,6 +1196,7 @@ grub_util_get_raid_grub_dev (const char *os_dev)
   }
   return grub_dev;
 }
+#endif
 
 enum grub_dev_abstraction_types
 grub_util_get_dev_abstraction_os (const char *os_dev)
@@ -1207,6 +1213,7 @@ grub_util_get_dev_abstraction_os (const char *os_dev)
   return GRUB_DEV_ABSTRACTION_NONE;
 }
 
+#ifdef GRUB_UTIL
 int
 grub_util_pull_device_os (const char *os_dev,
 			  enum grub_dev_abstraction_types ab)
@@ -1263,6 +1270,7 @@ grub_util_get_grub_dev_os (const char *os_dev)
 
   return grub_dev;
 }
+#endif
 
 static void *mp = NULL;
 static void
diff --git a/grub-core/osdep/unix/getroot.c b/grub-core/osdep/unix/getroot.c
index ee11b02fb6..62581ba601 100644
--- a/grub-core/osdep/unix/getroot.c
+++ b/grub-core/osdep/unix/getroot.c
@@ -16,8 +16,8 @@
  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <config.h>
 #include <config-util.h>
+#include <config.h>
 
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -567,6 +567,7 @@ grub_guess_root_devices (const char *dir_in)
 
 #endif
 
+#ifdef GRUB_UTIL
 void
 grub_util_pull_lvm_by_command (const char *os_dev)
 {
@@ -663,6 +664,7 @@ out:
   free (buf);
   free (vgid);
 }
+#endif
 
 /* ZFS has similar problems to those of btrfs (see above).  */
 void
diff --git a/include/grub/emu/misc.h b/include/grub/emu/misc.h
index f3a712a8b2..59b8038c60 100644
--- a/include/grub/emu/misc.h
+++ b/include/grub/emu/misc.h
@@ -39,7 +39,7 @@ void grub_fini_all (void);
 void grub_find_zpool_from_dir (const char *dir,
 			       char **poolname, char **poolfs);
 
-char *grub_make_system_path_relative_to_its_root (const char *path)
+char *EXPORT_FUNC (grub_make_system_path_relative_to_its_root) (const char *path)
  WARN_UNUSED_RESULT;
 int
 grub_util_device_is_mapped (const char *dev);