[lustre-devel] [PATCH 16/18] lustre: libcfs: restore original behavior in cfs_str2num_check

[NeilBrown]

On Mon, Jul 02 2018, James Simmons wrote:

> When cfs_str2num_check() moved from simple_strtoul to kstrtoul
> some of the functionality got lost. Restore handling hexidecimal
> number as well as '+' and '-'. Also handle any trailing spaces.
>
> Signed-off-by: James Simmons <uja.ornl at yahoo.com>
> WC-bug-id: https://jira.whamcloud.com/browse/LU-9325
> Reviewed-on: https://review.whamcloud.com/32217
> Reviewed-by: John L. Hammond <jhammond at whamcloud.com>
> Reviewed-by: Andreas Dilger <adilger at whamcloud.com>
> Reviewed-by: Dmitry Eremin <dmitry.eremin at intel.com>
> Reviewed-by: Oleg Drokin <green at whamcloud.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>  drivers/staging/lustre/lnet/libcfs/libcfs_string.c | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/lustre/lnet/libcfs/libcfs_string.c b/drivers/staging/lustre/lnet/libcfs/libcfs_string.c
> index e1fb126..e390b0b 100644
> --- a/drivers/staging/lustre/lnet/libcfs/libcfs_string.c
> +++ b/drivers/staging/lustre/lnet/libcfs/libcfs_string.c
> @@ -214,8 +214,10 @@ char *cfs_firststr(char *str, size_t size)
>  {
>  	bool all_numbers = true;
>  	char *endp, cache;
> +	int len;
>  	int rc;
>  
> +	endp = strim(str);

This looks bad.  The function now changes the string buffer, where it
didn't before.

>  	/**
>  	 * kstrouint can only handle strings composed
>  	 * of only numbers. We need to scan the string
> @@ -228,16 +230,25 @@ char *cfs_firststr(char *str, size_t size)
>  	 * After we are done the character at the
>  	 * position we placed '\0' must be restored.
>  	 */
> -	for (endp = str; endp < str + nob; endp++) {
> -		if (!isdigit(*endp)) {
> +	len = min((int)strlen(endp), nob);

As endp might be different from 'str, 'nob' is not meaningful in the
context of endp.

I'm guessing that mainline commit

Commit: c948390f10cc ("staging: lustre: llite: fix inconsistencies of root squash feature")

is related to this.

I cannot apply this patch as-is.  It is broken.  Possibly changing
   endp = strim(str);
to
   endp = str;

will fix it.

Thanks,
NeilBrown

> +	for (; endp < str + len; endp++) {
> +		if (!isdigit(*endp) && *endp != '-' &&
> +		    *endp != '+') {
>  			all_numbers = false;
>  			break;
>  		}
>  	}
> +
> +	/* Eat trailing space */
> +	if (!all_numbers && isspace(*endp)) {
> +		all_numbers = true;
> +		endp--;
> +	}
> +
>  	cache = *endp;
>  	*endp = '\0';
>  
> -	rc = kstrtouint(str, 10, num);
> +	rc = kstrtouint(str, 0, num);
>  	*endp = cache;
>  	if (rc || !all_numbers)
>  		return 0;
> -- 
> 1.8.3.1
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