Commit 6591be4a authored Jul 07, 2023 by @wuzhangjin Committed by Willy Tarreau Aug 23, 2023

tools/nolibc: __sysret: support syscalls who return a pointer



No official reference states the errno range, here aligns with musl and
glibc and uses [-MAX_ERRNO, -1] instead of all negative ones.

- musl: src/internal/syscall_ret.c
- glibc: sysdeps/unix/sysv/linux/sysdep.h

The MAX_ERRNO used by musl and glibc is 4095, just like the one nolibc
defined in tools/include/nolibc/errno.h.

Suggested-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/lkml/ZKKdD%2Fp4UkEavru6@1wt.eu/


Suggested-by: David Laight <David.Laight@ACULAB.COM>
Link: https://lore.kernel.org/linux-riscv/94dd5170929f454fbc0a10a2eb3b108d@AcuMS.aculab.com/


Signed-off-by: Zhangjin Wu <falcon@tinylab.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>

parent 6d1970e1

tools/include/nolibc/sys.h

+12 −5

Original line number	Diff line number	Diff line
		@@ -28,13 +28,20 @@
		#include "errno.h"
		#include "types.h"

		/* Syscall return helper, set errno as -ret when ret < 0 */

		/* Syscall return helper for library routines, set errno as -ret when ret is in
		* range of [-MAX_ERRNO, -1]
		*
		* Note, No official reference states the errno range here aligns with musl
		* (src/internal/syscall_ret.c) and glibc (sysdeps/unix/sysv/linux/sysdep.h)
		*/

		static __inline__ __attribute__((unused, always_inline))
		long __sysret(long ret)
		long __sysret(unsigned long ret)
		{
		if (ret < 0) {
		SET_ERRNO(-ret);
		ret = -1;
		if (ret >= (unsigned long)-MAX_ERRNO) {
		SET_ERRNO(-(long)ret);
		return -1;
		}
		return ret;
		}