Re: [PATCH 1/7] tools/nolibc: also handle _llseek system call

[David Laight]

On Sat, 18 Apr 2026 13:56:46 +0200
Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote:

> Apr 18, 2026 13:23:43 David Laight <david.laight.linux@xxxxxxxxx>:
> 
> > On Sat, 18 Apr 2026 12:19:56 +0200
> > Thomas Weißschuh <linux@xxxxxxxxxxxxxx> wrote:
> >  
> >> On some architectures the llseek system call contains a leading
> >> underscore. Also check for that one and prefer it over the lseek system
> >> call as it is necessary for 64-bit offset handling.
> >>  
> > ...  
> >> +#if defined(__NR_llseek)
> >> +   nr_llseek = __NR_llseek;
> >> +#else
> >> +   nr_llseek = __NR__llseek;
> >> +#endif  
> >
> > Is that test the right way around?
> > The commit messages says prefer _llseek, but that seems to prefer llseek.  
> 
> Yes. lseek is the ifdef case below.
> Here we have _llseek and llseek.
> lseek always exists, but may no handle 64 bit offsets.
> Only one of llseek and _llseek exists
> for one given architecture.

Ok, the fact that you said 'prefer' made me think that both might
sometimes exist.

	David

> 
> >> +
> >> +   ret = __nolibc_syscall5(nr_llseek, fd, offset >> 32, (uint32_t)offset, &loff, whence);
> >>     if (ret < 0)
> >>         result = ret;
> >>     else
> >>  
>