On Thu, Dec 2, 2021, at 6:43 PM, Adhemerval Zanella via Libc-alpha wrote: > 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. As a general rule yes, but we could make a deal that some specific bits headers are permanent API for use by things like this. They probably should be less of a dumping ground than bits/types.h though.
