string: implement strchrnul

We have at least two places opencoding strchrnul, one of them needlessly
iterating twice instead of once over the string. Replace both by calling
a common single pass implementation.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20210628051934.9604-1-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/string.c b/lib/string.c
index bad186586f..9aeb1d8830 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -274,6 +274,24 @@ char * _strchr(const char * s, int c)
 #endif
 EXPORT_SYMBOL(_strchr);
 
+#ifndef __HAVE_ARCH_STRCHRNUL
+/**
+ * strchrnul - Find and return a character in a string, or end of string
+ * @s: The string to be searched
+ * @c: The character to search for
+ *
+ * Returns pointer to first occurrence of 'c' in s. If c is not found, then
+ * return a pointer to the null byte at the end of s.
+ */
+char *strchrnul(const char *s, int c)
+{
+	while (*s && *s != (char)c)
+		s++;
+	return (char *)s;
+}
+EXPORT_SYMBOL(strchrnul);
+#endif
+
 #ifndef __HAVE_ARCH_STRRCHR
 /**
  * strrchr - Find the last occurrence of a character in a string