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-rw-r--r--lib/kstrtox.c64
1 files changed, 64 insertions, 0 deletions
diff --git a/lib/kstrtox.c b/lib/kstrtox.c
index 94be244e8441..d8a5cf66c316 100644
--- a/lib/kstrtox.c
+++ b/lib/kstrtox.c
@@ -321,6 +321,70 @@ int kstrtos8(const char *s, unsigned int base, s8 *res)
}
EXPORT_SYMBOL(kstrtos8);
+/**
+ * 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(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(kstrtobool_from_user);
+
#define kstrto_from_user(f, g, type) \
int f(const char __user *s, size_t count, unsigned int base, type *res) \
{ \