Re: [PATCH] uapi: Make __{u,s}64 match {u,}int64_t in userspace
From: Rich Felker <dalias@libc.org>
Date: 2021-12-02 15:34:27
Also in:
linux-arch, lkml, ltp
On Mon, Nov 22, 2021 at 10:19:59PM +0000, Zack Weinberg via Libc-alpha wrote:
On Mon, Nov 22, 2021, at 4:43 PM, Cyril Hrubis wrote:quoted
This changes the __u64 and __s64 in userspace on 64bit platforms from long long (unsigned) int to just long (unsigned) int in order to match the uint64_t and int64_t size in userspace.....quoted
+ +#include <asm/bitsperlong.h> + /* - * int-ll64 is used everywhere now. + * int-ll64 is used everywhere in kernel now. */ -#include <asm-generic/int-ll64.h> +#if __BITS_PER_LONG == 64 && !defined(__KERNEL__) +# include <asm-generic/int-l64.h> +#else +# include <asm-generic/int-ll64.h> +#endifI am all for matching __uN / __sN to uintN_t / intN_t in userspace, but may I suggest the technically simpler and guaranteed-to-be-accurate /* - * int-ll64 is used everywhere now. + * int-ll64 is used everywhere in kernel now. + * In user space match <stdint.h>. */ +#ifdef __KERNEL__ # include <asm-generic/int-ll64.h> +#elif __has_include (<bits/types.h>) +# include <bits/types.h> +typedef __int8_t __s8; +typedef __uint8_t __u8; +typedef __int16_t __s16; +typedef __uint16_t __u16; +typedef __int32_t __s32; +typedef __uint32_t __u32; +typedef __int64_t __s64; +typedef __uint64_t __u64; +#else +# include <stdint.h> +typedef int8_t __s8; +typedef uint8_t __u8; +typedef int16_t __s16; +typedef uint16_t __u16; +typedef int32_t __s32; +typedef uint32_t __u32; +typedef int64_t __s64; +typedef uint64_t __u64; +#endif The middle clause could be dropped if we are okay with all uapi headers potentially exposing the non-implementation-namespace names defined by <stdint.h>. I do not know what the musl libc equivalent of <bits/types.h> is.
We (musl) don't have an equivalent header or __-prefixed versions of these types. FWIW I don't think stdint.h exposes anything that would be problematic alongside arbitrary use of kernel headers. Rich