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

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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>
This commit is contained in:
Zhangjin Wu 2023-07-07 22:56:59 +08:00 committed by Willy Tarreau
parent 6d1970e1ef
commit 6591be4a73
1 changed files with 12 additions and 5 deletions
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17
tools/include/nolibc/sys.h
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@ -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;
}