tools: Clone the kernel's strtobool function

Copying it to tools/lib/string.c, the counterpart to the kernel's
lib/string.c.

This is preparation for enhancing BPF program configuration, which will
allow config string like 'inlines=yes'.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1447675815-166222-6-git-send-email-wangnan0@huawei.com
[ Copied it to tools/lib/string.c instead, to make it usable by other tools/ ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index f3a6db6ad732d95aad6ddd81dcf5b6860158f5e8..2e2f736c039c0efd09f2f30286e66735dbd166dd 100644 (file)
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -6,4 +6,6 @@
 
 void *memdup(const void *src, size_t len);
 
+int strtobool(const char *s, bool *res);
+
 #endif /* _LINUX_STRING_H_ */

diff --git a/tools/lib/string.c b/tools/lib/string.c
index ecfd43a9b24ef3c49c0a4586c3512c02cd640b28..065e54f42d8f1e20ebbf242b54443a32ec97800d 100644 (file)
--- 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;
+}