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/*
* Copyright(c) 2016 Hauke Mehrtens <hauke@hauke-m.de>
*
* Backport functionality introduced in Linux 4.6.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/export.h>
/**
* kstrtobool - convert common user inputs into boolean values
* @s: input string
* @res: result
*
* This routine returns 0 iff the first character is one of 'Yy1Nn0', or
* [oO][NnFf] for "on" and "off". Otherwise it will return -EINVAL. Value
* pointed to by res is updated upon finding a match.
*/
int kstrtobool(const char *s, bool *res)
{
if (!s)
return -EINVAL;
switch (s[0]) {
case 'y':
case 'Y':
case '1':
*res = true;
return 0;
case 'n':
case 'N':
case '0':
*res = false;
return 0;
case 'o':
case 'O':
switch (s[1]) {
case 'n':
case 'N':
*res = true;
return 0;
case 'f':
case 'F':
*res = false;
return 0;
default:
break;
}
default:
break;
}
return -EINVAL;
}
EXPORT_SYMBOL_GPL(kstrtobool);
/*
* Since "base" would be a nonsense argument, this open-codes the
* _from_user helper instead of using the helper macro below.
*/
int kstrtobool_from_user(const char __user *s, size_t count, bool *res)
{
/* Longest string needed to differentiate, newline, terminator */
char buf[4];
count = min(count, sizeof(buf) - 1);
if (copy_from_user(buf, s, count))
return -EFAULT;
buf[count] = '\0';
return kstrtobool(buf, res);
}
EXPORT_SYMBOL_GPL(kstrtobool_from_user);
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