linux-kernel - [PATCH v5] char: hw_random: core.c: Changed from using strncat to strlcat

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Message-Id: <1413494243-30867-1-git-send-email-rickard_strandqvist@spectrumdigital.se>
Date:	Thu, 16 Oct 2014 23:17:23 +0200
From:	Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
To:	Matt Mackall <mpm@...enic.com>,
	Herbert Xu <herbert@...dor.apana.org.au>
Cc:	Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>,
	Torsten Duwe <duwe@....de>,
	Jason Cooper <jason@...edaemon.net>,
	"Theodore Ts'o" <tytso@....edu>, Amit Shah <amit.shah@...hat.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Kees Cook <keescook@...omium.org>,
	Dan Carpenter <dan.carpenter@...cle.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH v5] char: hw_random: core.c:  Changed from using strncat to strlcat

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.

Signed-off-by: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se>
Reviewed-by: Jason Cooper <jason@...edaemon.net>
---
 drivers/char/hw_random/core.c |   12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index aa30a25..1500cfd 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -281,7 +281,6 @@ static ssize_t hwrng_attr_available_show(struct device *dev,
 					 char *buf)
 {
 	int err;
-	ssize_t ret = 0;
 	struct hwrng *rng;
 
 	err = mutex_lock_interruptible(&rng_mutex);
@@ -289,16 +288,13 @@ 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++;
+	strlcat(buf, "\n", PAGE_SIZE);
 	mutex_unlock(&rng_mutex);
 
-	return ret;
+	return strlen(buf);
 }
 
 static DEVICE_ATTR(rng_current, S_IRUGO | S_IWUSR,
-- 
1.7.10.4

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