Re: [PATCH 7/9] pkeys.7: Update the example to match glibc

[Stephen Kitt <steve@sk2.org>]

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Hi Alex,

On Sat, 8 Jan 2022 02:59:12 +0100, "Alejandro Colomar (man-pages)"
<alx.manpages@gmail.com> wrote:
> On 1/7/22 17:46, Stephen Kitt wrote:
> > glibc 2.27 introduced support for the pkeys functions, but the glibc
> > versions don't match those declared in the example. Update the example
> > to match glibc, and avoid declaring the functions if glibc is new
> > enough. >
> > Signed-off-by: Stephen Kitt <steve@sk2.org>  
> 
> 
> There are a few problems with the prototypes.
> 
> 
> alx@ady1:~/src/gnu/glibc$ grep_glibc_prototype wrpkru
> alx@ady1:~/src/gnu/glibc$ grep -rn define.wrpkru
> alx@ady1:~/src/gnu/glibc$ grep_glibc_prototype pkey_set
> 60:int pkey_set (int __key, unsigned int __access_rights) __THROW;
> alx@ady1:~/src/gnu/glibc$ grep_glibc_prototype pkey_mprotect
> 72:int pkey_mprotect (void *__addr, size_t __len, int __prot, int 
> __pkey) __THROW;
> alx@ady1:~/src/gnu/glibc$ grep_glibc_prototype pkey_alloc
> 56:int pkey_alloc (unsigned int __flags, unsigned int __access_rights) 
> __THROW;
> alx@ady1:~/src/gnu/glibc$ grep_glibc_prototype pkey_free
> 68:int pkey_free (int __key) __THROW;
> 
> 
> As you see above, I couldn't find wrpkru().  Are you sure it exists in 
> glibc?

It doesn’t exist in glibc(), but if we use the glibc version of pkey_set(),
it’s not needed in the example. In glibc, the equivalent function is
pkey_write(), but that’s an implementation detail, it’s not part of the API.

> pkey_mprotect(3) uses 'int' instead of 'unsigned long'.  Would you mind 
> fixind that one too?
> 
> pkey_set(3) uses 'unsigned int' instead of 'unsigned long'.  Please fix 
> that one.
> 
> pkey_free(3) uses 'int' instead of 'unsigned long'.  Would you mind 
> fixing that one too?

Right, I’ll take care of all that.

> BTW, I need to modify grep_glibc_prototype() so that it always prints 
> the file name, even if only one file is passed to grep (adding /dev/null 
> to the file list).
> 
> 
> A part from that, I prefer EXAMPLES to be as simple as possible, so I'd 
> do 2 patches.  One to match the definitions to the glibc ones, and then 
> one commit removing old code, assuming glibc is new enough.  Would you 
> mind sending a subsequent patch to remove everything under #if ... #endif?

Right, will do!

Regards,

Stephen

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