From 508a8b61aca5b1cee9a15f13a14bfa512b7252d0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timoth=C3=A9e=20Ravier?= <tim@siosm.fr>
Date: Fri, 13 Sep 2024 19:14:43 +0200
Subject: [PATCH] bootloader/grub2: Handle empty static configs

In #3205, we introduced a check to skip re-generating the GRUB config if
we detect that static configs are in used by looking at bootupd's state.

Unfortunately this check is incomplete and does not account for present
but null entries in the JSON state file.

A proper fix would be to parse the JSON but this requires a larger code
change.

Fixes: https://github.com/ostreedev/ostree/issues/3295
Fixes: https://github.com/ostreedev/ostree/pull/3205
---
 src/libostree/ostree-bootloader-grub2.c      | 10 +++++++---
 tests/kolainst/destructive/bootupd-static.sh |  2 +-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/libostree/ostree-bootloader-grub2.c b/src/libostree/ostree-bootloader-grub2.c
index e15fb9b6..f2d73d33 100644
--- a/src/libostree/ostree-bootloader-grub2.c
+++ b/src/libostree/ostree-bootloader-grub2.c
@@ -30,6 +30,7 @@
 #define BOOTUPD_CONFIG "boot/bootupd-state.json"
 // Horrible hack, to avoid including a JSON parser we just grep for this
 #define BOOTUPD_CONFIG_STATIC_JSON_FRAGMENT "\"static-configs\""
+#define BOOTUPD_CONFIG_STATIC_JSON_FRAGMENT_NULL "\"static-configs\":null"
 
 /* Maintain backwards compatibility with legacy GRUB
  * installations that might rely on the -16 suffix
@@ -90,9 +91,12 @@ _ostree_bootloader_grub2_query (OstreeBootloader *bootloader, gboolean *out_is_a
         return glnx_prefix_error (error, "Failed to read bootupd config");
       if (strstr (bootupd_config_contents, BOOTUPD_CONFIG_STATIC_JSON_FRAGMENT) != NULL)
         {
-          g_debug ("Found static bootupd config");
-          *out_is_active = FALSE;
-          return TRUE;
+          if (strstr (bootupd_config_contents, BOOTUPD_CONFIG_STATIC_JSON_FRAGMENT_NULL) == NULL)
+            {
+              g_debug ("Found static bootupd config");
+              *out_is_active = FALSE;
+              return TRUE;
+            }
         }
     }
 
diff --git a/tests/kolainst/destructive/bootupd-static.sh b/tests/kolainst/destructive/bootupd-static.sh
index cf836813..670178e4 100755
--- a/tests/kolainst/destructive/bootupd-static.sh
+++ b/tests/kolainst/destructive/bootupd-static.sh
@@ -10,7 +10,7 @@ bootupd_state=/boot/bootupd-state.json
 mount -o remount,rw /boot
 if grep -qFe "\"static-configs\"" "${bootupd_state}"; then
     echo "Host is using static configs already, overriding this"
-    jq 'del(.["static-configs"])' < "${bootupd_state}" > "${bootupd_state}".new
+    jq --compact-output '.["static-configs"] = null' < "${bootupd_state}" > "${bootupd_state}".new
     mv "${bootupd_state}.new" "${bootupd_state}"
 fi