[RFC v3 6/7] sprintf: Add [V]STPRINTF()

[Alejandro Colomar <alx@kernel.org>]

These macros take the array size argument implicitly to avoid programmer
mistakes.  This guarantees that the input is an array, unlike the common
call

	snprintf(buf, sizeof(buf), ...);

which is dangerous if the programmer passes a pointer.

These macros are essentially the same as the 2-argument version of
strscpy(), but with a formatted string.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
---
 include/linux/sprintf.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/sprintf.h b/include/linux/sprintf.h
index c3dbfd2efd2b..6080d3732055 100644
--- a/include/linux/sprintf.h
+++ b/include/linux/sprintf.h
@@ -4,6 +4,10 @@
 
 #include <linux/compiler_attributes.h>
 #include <linux/types.h>
+#include <linux/array_size.h>
+
+#define STPRINTF(a, fmt, ...)  stprintf(a, ARRAY_SIZE(a), fmt, ##__VA_ARGS__)
+#define VSTPRINTF(a, fmt, ap)  vstprintf(a, ARRAY_SIZE(a), fmt, ap)
 
 int num_to_str(char *buf, int size, unsigned long long num, unsigned int width);
 
-- 
2.50.0