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-rw-r--r--tools/lib/string.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/tools/lib/string.c b/tools/lib/string.c
index ecfd43a9b24e..065e54f42d8f 100644
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -1,5 +1,20 @@
+/*
+ *  linux/tools/lib/string.c
+ *
+ *  Copied from linux/lib/string.c, where it is:
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  More specifically, the first copied function was strtobool, which
+ *  was introduced by:
+ *
+ *  d0f1fed29e6e ("Add a strtobool function matching semantics of existing in kernel equivalents")
+ *  Author: Jonathan Cameron <jic23@cam.ac.uk>
+ */
+
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 #include <linux/string.h>
 
 /**
@@ -17,3 +32,31 @@ void *memdup(const void *src, size_t len)
 
 	return p;
 }
+
+/**
+ * strtobool - convert common user inputs into boolean values
+ * @s: input string
+ * @res: result
+ *
+ * This routine returns 0 iff the first character is one of 'Yy1Nn0'.
+ * Otherwise it will return -EINVAL.  Value pointed to by res is
+ * updated upon finding a match.
+ */
+int strtobool(const char *s, bool *res)
+{
+	switch (s[0]) {
+	case 'y':
+	case 'Y':
+	case '1':
+		*res = true;
+		break;
+	case 'n':
+	case 'N':
+	case '0':
+		*res = false;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}