On 02/12/2021 20:29, Rich Felker wrote: > On Thu, Dec 02, 2021 at 10:34:23AM -0500, Rich Felker wrote: >> 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: >>>> 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. >>> .... >>>> + >>>> +#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> >>>> +#endif >>> >>> I 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. > > Also, per glibc's bits/types.h: > > /* > * Never include this file directly; use <sys/types.h> instead. > */ > > it's not permitted (not supported usage) to #include <bits/types.h>. > So I think the above patch is wrong for glibc too. As I understand it, > this is general policy for bits/* -- they're only intended to work as > included by the libc system headers, not directly by something else. You are right, the idea is to allow glibc to create and remove internal headers.
