2020-11-24 16:04:23

by Min Li

Subject: [PATCH v2 net] ptp: clockmatrix: bug fix for idtcm_strverscmp

From: Min Li <[email protected]>

Feed kstrtou8 with NULL terminated string.

Changes since v1:
-Use sscanf to get rid of adhoc string parse.

Signed-off-by: Min Li <[email protected]>
---
drivers/ptp/ptp_clockmatrix.c | 53 +++++++++++++++----------------------------
1 file changed, 18 insertions(+), 35 deletions(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index e020faf..12d939f 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -103,43 +103,26 @@ static int timespec_to_char_array(struct timespec64 const *ts,
return 0;
}

-static int idtcm_strverscmp(const char *ver1, const char *ver2)
+static int idtcm_strverscmp(const char *version1, const char *version2)
{
- u8 num1;
- u8 num2;
- int result = 0;
-
- /* loop through each level of the version string */
- while (result == 0) {
- /* extract leading version numbers */
- if (kstrtou8(ver1, 10, &num1) < 0)
- return -1;
-
- if (kstrtou8(ver2, 10, &num2) < 0)
- return -1;
-
- /* if numbers differ, then set the result */
- if (num1 < num2)
- result = -1;
- else if (num1 > num2)
- result = 1;
- else {
- /* if numbers are the same, go to next level */
- ver1 = strchr(ver1, '.');
- ver2 = strchr(ver2, '.');
- if (!ver1 && !ver2)
- break;
- else if (!ver1)
- result = -1;
- else if (!ver2)
- result = 1;
- else {
- ver1++;
- ver2++;
- }
- }
+ u8 ver1[3], ver2[3];
+ int i;
+
+ if (sscanf(version1, "%hhu.%hhu.%hhu",
+ &ver1[0], &ver1[1], &ver1[2]) < 0)
+ return -1;
+ if (sscanf(version2, "%hhu.%hhu.%hhu",
+ &ver2[0], &ver2[1], &ver2[2]) < 0)
+ return -1;
+
+ for (i = 0; i < 3; i++) {
+ if (ver1[i] > ver2[i])
+ return 1;
+ if (ver1[i] < ver2[i])
+ return -1;
}
- return result;
+
+ return 0;
}

static int idtcm_xfer_read(struct idtcm *idtcm,
--
2.7.4

2020-11-25 00:09:21

by Richard Cochran

Subject: Re: [PATCH v2 net] ptp: clockmatrix: bug fix for idtcm_strverscmp

On Tue, Nov 24, 2020 at 11:01:26AM -0500, [email protected] wrote:
> From: Min Li <[email protected]>
>
> Feed kstrtou8 with NULL terminated string.
>
> Changes since v1:
> -Use sscanf to get rid of adhoc string parse.

This is much nicer. Small issue remains...

> + u8 ver1[3], ver2[3];
> + int i;
> +
> + if (sscanf(version1, "%hhu.%hhu.%hhu",
> + &ver1[0], &ver1[1], &ver1[2]) < 0)
> + return -1;

The sscanf function returns the number of scanned items, and so you
should check that it returns 3 (three).

> + if (sscanf(version2, "%hhu.%hhu.%hhu",
> + &ver2[0], &ver2[1], &ver2[2]) < 0)
> + return -1;

Same here.

Thanks,
Richard