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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 12 Dec 2023 18:23:45 +0100
Subject: [PATCH] fw_env: fix reading NVMEM device's "compatible" value
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Call to fread() was changed to check for return value. The problem is it
can't be checked for returning 1 (as it is) to determine success.
We call fread() with buffer size as "size" argument. Reading any
"compatible" value shorter than buffer size will result in returning 0
even on success.
Modify code to use fstat() to determine expected read length.
This fixes regression that broke using fw_env with NVMEM devices.
Fixes: c059a22b7776 ("tools: env: fw_env: Fix unused-result warning")
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
tools/env/fw_env.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -1732,6 +1732,7 @@ static int find_nvmem_device(void)
}
while (!nvmem && (dent = readdir(dir))) {
+ struct stat s;
FILE *fp;
size_t size;
@@ -1749,14 +1750,22 @@ static int find_nvmem_device(void)
continue;
}
- size = fread(buf, sizeof(buf), 1, fp);
+ if (fstat(fileno(fp), &s)) {
+ fprintf(stderr, "Failed to fstat %s\n", comp);
+ goto next;
+ }
+
+ if (s.st_size >= sizeof(buf)) {
+ goto next;
+ }
+
+ size = fread(buf, s.st_size, 1, fp);
if (size != 1) {
fprintf(stderr,
"read failed about %s\n", comp);
- fclose(fp);
- return -EIO;
+ goto next;
}
-
+ buf[s.st_size] = '\0';
if (!strcmp(buf, "u-boot,env")) {
bytes = asprintf(&nvmem, "%s/%s/nvmem", path, dent->d_name);
@@ -1765,6 +1774,7 @@ static int find_nvmem_device(void)
}
}
+next:
fclose(fp);
}
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