[PATCH 5/6] rockchip: puma-rk3399: fix modified boot_targets detection

[Quentin Schulz]

From: Quentin Schulz <quentin.schulz at theobroma-systems.com>

U-Boot proper automatically modifies boot_targets to swap the order in
which MMC storage media are used for standard boot based on which MMC
storage medium was used to load U-Boot proper. This is however only done
if the user has not changed it manually, therefore a check between the
default and current value is done.

This used to work fine until the migration to standard boot where
boot_targets value size in the default environment went above the 32
characters that env_get_default function can return, thus resulting in a
truncated variable.

Therefore the check between default and current value would always fail.

By using the newly added env_get_default_into function, a buffer of
the appropriate size can be allocated on the stack to get the whole
value of boot_targets in the default environment and thus fixing the
check.

Cc: Quentin Schulz <foss+uboot at 0leil.net>
Signed-off-by: Quentin Schulz <quentin.schulz at theobroma-systems.com>
---
 board/theobroma-systems/puma_rk3399/puma-rk3399.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/board/theobroma-systems/puma_rk3399/puma-rk3399.c b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
index 1b7a39b0474..df667fae5fc 100644
--- a/board/theobroma-systems/puma_rk3399/puma-rk3399.c
+++ b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
@@ -54,7 +54,9 @@ static int setup_boottargets(void)
 {
 	const char *boot_device =
 		ofnode_read_chosen_string("u-boot,spl-boot-device");
-	char *env_default, *env;
+	char env_default[sizeof(BOOT_TARGETS)];
+	char *env;
+	int ret;
 
 	if (!boot_device) {
 		debug("%s: /chosen/u-boot,spl-boot-device not set\n",
@@ -63,7 +65,10 @@ static int setup_boottargets(void)
 	}
 	debug("%s: booted from %s\n", __func__, boot_device);
 
-	env_default = env_get_default("boot_targets");
+	ret = env_get_default_into("boot_targets", env_default,
+				   sizeof(env_default));
+	if (ret < 0)
+		env_default[0] = '\0';
 	env = env_get("boot_targets");
 	if (!env) {
 		debug("%s: boot_targets does not exist\n", __func__);

-- 
2.41.0