[PATCH nolibc 04/19] tools/nolibc: add stdarg.h header

From: Paul E. McKenney
Date: Thu Oct 12 2023 - 15:32:49 EST


From: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>

This allows nolic to work with `-nostdinc` avoiding any reliance on
system headers.

The implementation has been lifted from musl libc 1.2.4.
There is already an implementation of stdarg.h in include/linux/stdarg.h
but that is GPL licensed and therefore not suitable for nolibc.

The used compiler builtins have been validated to be at least available
since GCC 4.1.2 and clang 3.0.0.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
tools/include/nolibc/Makefile | 1 +
tools/include/nolibc/nolibc.h | 4 ++--
tools/include/nolibc/stdarg.h | 16 ++++++++++++++++
tools/include/nolibc/stdio.h | 3 +--
tools/include/nolibc/sys.h | 2 +-
5 files changed, 21 insertions(+), 5 deletions(-)
create mode 100644 tools/include/nolibc/stdarg.h

diff --git a/tools/include/nolibc/Makefile b/tools/include/nolibc/Makefile
index 909b6eb500fe..e69c26abe1ea 100644
--- a/tools/include/nolibc/Makefile
+++ b/tools/include/nolibc/Makefile
@@ -34,6 +34,7 @@ all_files := \
signal.h \
stackprotector.h \
std.h \
+ stdarg.h \
stdint.h \
stdlib.h \
string.h \
diff --git a/tools/include/nolibc/nolibc.h b/tools/include/nolibc/nolibc.h
index 1f8d821000ac..989e707263a4 100644
--- a/tools/include/nolibc/nolibc.h
+++ b/tools/include/nolibc/nolibc.h
@@ -74,10 +74,10 @@
* -I../nolibc -o hello hello.c -lgcc
*
* The available standard (but limited) include files are:
- * ctype.h, errno.h, signal.h, stdio.h, stdlib.h, string.h, time.h
+ * ctype.h, errno.h, signal.h, stdarg.h, stdio.h, stdlib.h, string.h, time.h
*
* In addition, the following ones are expected to be provided by the compiler:
- * float.h, stdarg.h, stddef.h
+ * float.h, stddef.h
*
* The following ones which are part to the C standard are not provided:
* assert.h, locale.h, math.h, setjmp.h, limits.h
diff --git a/tools/include/nolibc/stdarg.h b/tools/include/nolibc/stdarg.h
new file mode 100644
index 000000000000..c628b5783da6
--- /dev/null
+++ b/tools/include/nolibc/stdarg.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Variadic argument support for NOLIBC
+ * Copyright (C) 2005-2020 Rich Felker, et al.
+ */
+
+#ifndef _NOLIBC_STDARG_H
+#define _NOLIBC_STDARG_H
+
+typedef __builtin_va_list va_list;
+#define va_start(v, l) __builtin_va_start(v, l)
+#define va_end(v) __builtin_va_end(v)
+#define va_arg(v, l) __builtin_va_arg(v, l)
+#define va_copy(d, s) __builtin_va_copy(d, s)
+
+#endif /* _NOLIBC_STDARG_H */
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index cae402c11e57..d7ef43973916 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -7,13 +7,12 @@
#ifndef _NOLIBC_STDIO_H
#define _NOLIBC_STDIO_H

-#include <stdarg.h>
-
#include "std.h"
#include "arch.h"
#include "errno.h"
#include "types.h"
#include "sys.h"
+#include "stdarg.h"
#include "stdlib.h"
#include "string.h"

diff --git a/tools/include/nolibc/sys.h b/tools/include/nolibc/sys.h
index fdb6bd6c0e2f..b478750c9004 100644
--- a/tools/include/nolibc/sys.h
+++ b/tools/include/nolibc/sys.h
@@ -7,7 +7,6 @@
#ifndef _NOLIBC_SYS_H
#define _NOLIBC_SYS_H

-#include <stdarg.h>
#include "std.h"

/* system includes */
@@ -25,6 +24,7 @@

#include "arch.h"
#include "errno.h"
+#include "stdarg.h"
#include "types.h"


--
2.40.1