linux-kernel - [PATCH v1 1/2] mmc-utils: Use memcpy instead of strncpy

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Date:   Sun, 14 Nov 2021 21:43:30 +0100
From:   Bean Huo <huobean@...il.com>
To:     ulf.hansson@...aro.org, adrian.hunter@...el.com,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     beanhuo@...ron.com
Subject: [PATCH v1 1/2] mmc-utils: Use memcpy instead of strncpy

From: Bean Huo <beanhuo@...ron.com>

The -Wstringop-truncation warning added in GCC 8.0:
    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82944

If you use the GCC > v8.0, you probably will get this compilation error:

error: ‘__builtin_strncpy’ output may be truncated copying 8
bytes from a string of length 511 [-Werror=stringop-truncation]

Use memcpy instead of strncpy to avoid this compilation error.

Signed-off-by: Bean Huo <beanhuo@...ron.com>
---
 mmc_cmds.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mmc_cmds.c b/mmc_cmds.c
index 205e6e5b89f9..ecbde3937c81 100644
--- a/mmc_cmds.c
+++ b/mmc_cmds.c
@@ -1835,7 +1835,8 @@ int do_read_extcsd(int nargs, char **argv)
 
 	if (ext_csd_rev >= 7) {
                 memset(lbuf, 0, sizeof(lbuf));
-		strncpy(lbuf, (char*)&ext_csd[EXT_CSD_FIRMWARE_VERSION], 8);
+		memcpy(lbuf, (char*)&ext_csd[EXT_CSD_FIRMWARE_VERSION], 8);
+		lbuf[8] = '\0';
 		printf("eMMC Firmware Version: %s\n", lbuf);
 		printf("eMMC Life Time Estimation A [EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]: 0x%02x\n",
 			ext_csd[EXT_CSD_DEVICE_LIFE_TIME_EST_TYP_A]);
-- 
2.25.1