Commit 35c35493 authored by Chuhong Yuan's avatar Chuhong Yuan Committed by Petr Mladek
Browse files

printk: Replace strncmp() with str_has_prefix() 

strncmp(str, const, len) is error-prone because len is easy to have typo.
An example is the hard-coded len has counting error or sizeof(const)
forgets - 1.

So we prefer using newly introduced str_has_prefix() to substitute
such strncmp() to make code better.

Link: http://lkml.kernel.org/r/20190809071034.17279-1-hslester96@gmail.com


Cc: "Steven Rostedt" <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarChuhong Yuan <hslester96@gmail.com>
Reviewed-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: Slightly updated and reformatted the commit message.]
Signed-off-by: default avatarPetr Mladek <pmladek@suse.com>
parent 8ebea6ea

kernel/printk/braille.c

+11 −4
Original line number Diff line number Diff line
@@ -11,11 +11,18 @@ 


int _braille_console_setup(char **str, char **brl_options)

{

	if (!strncmp(*str, "brl,", 4)) {

	size_t len;



	len = str_has_prefix(*str, "brl,");

	if (len) {

		*brl_options = "";

		*str += 4;

	} else if (!strncmp(*str, "brl=", 4)) {

		*brl_options = *str + 4;

		*str += len;

		return 0;

	}



	len = str_has_prefix(*str, "brl=");

	if (len) {

		*brl_options = *str + len;

		*str = strchr(*brl_options, ',');

		if (!*str) {

			pr_err("need port name after brl=\n");

kernel/printk/printk.c

+16 −6
Original line number Diff line number Diff line
@@ -118,19 +118,29 @@ static unsigned int __read_mostly devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; 


static int __control_devkmsg(char *str)

{

	size_t len;



	if (!str)

		return -EINVAL;



	if (!strncmp(str, "on", 2)) {

	len = str_has_prefix(str, "on");

	if (len) {

		devkmsg_log = DEVKMSG_LOG_MASK_ON;

		return 2;

	} else if (!strncmp(str, "off", 3)) {

		return len;

	}



	len = str_has_prefix(str, "off");

	if (len) {

		devkmsg_log = DEVKMSG_LOG_MASK_OFF;

		return 3;

	} else if (!strncmp(str, "ratelimit", 9)) {

		return len;

	}



	len = str_has_prefix(str, "ratelimit");

	if (len) {

		devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;

		return 9;

		return len;

	}



	return -EINVAL;

}

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