[igt-dev] [PATCH i-g-t 2/2] stubs: provide implementation for memfd_create

[Lucas De Marchi]

On Thu, Jul 19, 2018 at 4:20 PM Antonio Argenziano
<antonio.argenziano at intel.com> wrote:
>
>
>
> On 19/07/18 13:54, Lucas De Marchi wrote:
> > When libc misses memfd_create(), provide a stub implementation to go
> > through the syscall() route. Syscall numbers are provided for platforms
> > currently supported by i-g-t only.
> >
> > Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> > ---
> >   lib/stubs/syscall/sys/mman.h | 37 ++++++++++++++++++++++++++++++++++++
> >   meson.build                  |  3 +++
> >   2 files changed, 40 insertions(+)
> >   create mode 100644 lib/stubs/syscall/sys/mman.h
> >
> > diff --git a/lib/stubs/syscall/sys/mman.h b/lib/stubs/syscall/sys/mman.h
> > new file mode 100644
> > index 00000000..36060bda
> > --- /dev/null
> > +++ b/lib/stubs/syscall/sys/mman.h
> > @@ -0,0 +1,37 @@
> > +/* SPDX-License-Identifier: MIT */
> > +
> > +#pragma once
> > +
> > +#include_next <sys/mman.h>
> > +
> > +#if !HAVE_MEMFD_CREATE
>
> Maybe include <linux/memfd.h> conditionally. I don't think we need it
> for anything else.

oh... I added it to sys/mman.h when in reality should have added to
sys/memfd.h it seems?

and the man page is wrong?

NAME
       memfd_create - create an anonymous file

SYNOPSIS
       #include <sys/memfd.h>

       int memfd_create(const char *name, unsigned int flags);

Interesting that it worked as is. Where's my coffee?

Lucas De Marchi

>
> Thanks,
> Antonio
>
> > +#include <errno.h>
> > +#include <sys/syscall.h>
> > +#include <sys/types.h>
> > +#include <unistd.h>
> > +
> > +#ifndef __NR_memfd_create
> > +#if defined __x86_64__
> > +#define __NR_memfd_create 319
> > +#elif defined __i386__
> > +#define __NR_memfd_create 356
> > +#elif defined __arm__
> > +#define __NR_memfd_create 385
> > +#else
> > +#warning "__NR_memfd_create unknown for your architecture"
> > +#endif
> > +#endif
> > +
> > +static inline int missing_memfd_create(const char *name, unsigned int flags)
> > +{
> > +#ifdef __NR_memfd_create
> > +     return syscall(__NR_memfd_create, name, flags);
> > +#else
> > +     errno = ENOSYS;
> > +     return -1;
> > +#endif
> > +}
> > +
> > +#define memfd_create missing_memfd_create
> > +
> > +#endif
> > diff --git a/meson.build b/meson.build
> > index c24a3cf4..188301ca 100644
> > --- a/meson.build
> > +++ b/meson.build
> > @@ -196,6 +196,9 @@ if cc.has_member('struct sysinfo', 'totalram',
> >       config.set('HAVE_STRUCT_SYSINFO_TOTALRAM', 1)
> >   endif
> >
> > +have = cc.has_function('memfd_create', prefix : '''#include <sys/mman.h>''', args : '-D_GNU_SOURCE')
> > +config.set10('HAVE_MEMFD_CREATE', have)
> > +
> >   add_project_arguments('-D_GNU_SOURCE', language : 'c')
> >   add_project_arguments('-include', 'config.h', language : 'c')
> >
> >
> _______________________________________________
> igt-dev mailing list
> igt-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/igt-dev



-- 
Lucas De Marchi