Re: [PATCH v4] char: hw_random: core.c: Changed from using strncat to strlcat

From: Jason Cooper
Date: Thu Oct 16 2014 - 14:26:06 EST


On Thu, Oct 16, 2014 at 08:15:55PM +0200, Rickard Strandqvist wrote:
> The buf is used to hold the list of hwrng devices registered.
> The old code ensures we don't walk off the end of buf as we
> fill it, but it's unnecessarily complicated and thus difficult
> to maintain. Simplify it by using strlcat.

> We also ensure the string within buf is NULL terminated
> so the final strlen is ok.

This text is no longer necessary.

>
> Signed-off-by: Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx>

Please add my:

Reviewed-by: Jason Cooper <jason@xxxxxxxxxxxxxx>

to the next version of this patch. It makes the maintainers job a *lot*
easier not having to sift through old threads collecting up all the
tags.

thx,

Jason.

> ---
> drivers/char/hw_random/core.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
> index aa30a25..25599ea 100644
> --- a/drivers/char/hw_random/core.c
> +++ b/drivers/char/hw_random/core.c
> @@ -281,7 +281,7 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
> char *buf)
> {
> int err;
> - ssize_t ret = 0;
> + ssize_t ret;
> struct hwrng *rng;
>
> err = mutex_lock_interruptible(&rng_mutex);
> @@ -289,13 +289,10 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
> return -ERESTARTSYS;
> buf[0] = '\0';
> list_for_each_entry(rng, &rng_list, list) {
> - strncat(buf, rng->name, PAGE_SIZE - ret - 1);
> - ret += strlen(rng->name);
> - strncat(buf, " ", PAGE_SIZE - ret - 1);
> - ret++;
> + strlcat(buf, rng->name, PAGE_SIZE);
> + strlcat(buf, " ", PAGE_SIZE);
> }
> - strncat(buf, "\n", PAGE_SIZE - ret - 1);
> - ret++;
> + ret = strlcat(buf, "\n", PAGE_SIZE);
> mutex_unlock(&rng_mutex);
>
> return ret;
> --
> 1.7.10.4
>
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