[PATCH v4 13/19] use fw_path prefix when fallback searching for grub config

[Robbie Harwood]

From: Mark Salter <msalter@redhat.com>

When PXE booting via UEFI firmware, grub was searching for grub.cfg in
the fw_path directory where the grub application was found.  If that
didn't exist, a fallback search would look for config file names based
on MAC and IP address.  However, the search would look in the prefix
directory which may not be the same fw_path.  This patch changes that
behavior to use the fw_path directory for the fallback search.  Only if
fw_path is NULL will the prefix directory be searched.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 grub-core/normal/main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/grub-core/normal/main.c b/grub-core/normal/main.c
index a557ba5c9c..dfdfd56e06 100644
--- a/grub-core/normal/main.c
+++ b/grub-core/normal/main.c
@@ -322,7 +322,7 @@ grub_cmd_normal (struct grub_command *cmd __attribute__ 
((unused)),
       char *config;
       const char *prefix, *fw_path;
 
-      fw_path = grub_env_get ("fw_path");
+      prefix = fw_path = grub_env_get ("fw_path");
       if (fw_path)
        {
          config = grub_xasprintf ("%s/grub.cfg", fw_path);
@@ -345,7 +345,8 @@ grub_cmd_normal (struct grub_command *cmd __attribute__ 
((unused)),
            }
        }
 
-      prefix = grub_env_get ("prefix");
+      if (!prefix)
+        prefix = grub_env_get ("prefix");
       if (prefix)
         {
           grub_size_t config_len;
-- 
2.39.0