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From ad5444c5498cb8e12c874488be45a29369fc6532 Mon Sep 17 00:00:00 2001
From: Ming Liu <liu.ming50@gmail.com>
Date: Thu, 30 Jul 2020 14:16:24 +0200
Subject: [PATCH] Dont store to device if no value changes
Upstream-Status: Submitted
When fw_setenv is called, it could happen that the new value is same
with the old one, in which case, we should avoid storing data to
device.
Reference:
http://patchwork.ozlabs.org/project/swupdate/patch/20200804202120.31374-1-liu.ming50@gmail.com/
Signed-off-by: Ming Liu <liu.ming50@gmail.com>
---
src/fw_printenv.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)
diff --git a/src/fw_printenv.c b/src/fw_printenv.c
index 18887f9..8b830d5 100644
--- a/src/fw_printenv.c
+++ b/src/fw_printenv.c
@@ -151,19 +151,32 @@ int main (int argc, char **argv) {
}
}
} else { /* setenv branch */
- if (scriptfile)
+ bool need_store = false;
+ if (scriptfile) {
libuboot_load_file(ctx, scriptfile);
- else {
+ need_store = true;
+ } else {
for (i = 0; i < argc; i += 2) {
- if (i + 1 == argc)
- libuboot_set_env(ctx, argv[i], NULL);
- else
- libuboot_set_env(ctx, argv[i], argv[i+1]);
+ value = libuboot_get_env(ctx, argv[i]);
+ if (i + 1 == argc) {
+ if (value != NULL) {
+ libuboot_set_env(ctx, argv[i], NULL);
+ need_store = true;
+ }
+ } else {
+ if (value == NULL || strcmp(value, argv[i+1]) != 0) {
+ libuboot_set_env(ctx, argv[i], argv[i+1]);
+ need_store = true;
+ }
+ }
}
}
- ret = libuboot_env_store(ctx);
- if (ret)
- fprintf(stderr, "Error storing the env\n");
+
+ if (need_store) {
+ ret = libuboot_env_store(ctx);
+ if (ret)
+ fprintf(stderr, "Error storing the env\n");
+ }
}
libuboot_close(ctx);
--
2.28.0
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