Re: [musl] Re: [PATCH v3] add renameat2 linux syscall wrapper

[Rich Felker <dalias@libc.org>]

On Mon, May 20, 2024 at 06:42:55PM -0700, T A wrote:
> Hi Rich,
> 
> I think this v3 patch addressed all your suggestions. Are any other
> improvements needed?

Looks good. I'll go ahead and merge.

> 
> Thanks,
> Tony
> 
> On Mon, May 6, 2024, 20:28 Tony Ambardar <tony.ambardar@gmail.com> wrote:
> 
> > This syscall is available since Linux 3.15 and also implemented in glibc
> > from version 2.28. It is commonly used in filesystem or security contexts.
> >
> > Constants RENAME_NOREPLACE, RENAME_EXCHANGE, RENAME_WHITEOUT are guarded by
> > _GNU_SOURCE as with glibc.
> >
> > Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
> > ---
> > v2 -> v3:
> >  * call SYS_renameat first if applicable
> >  * drop unneeded error code handling
> >
> > v1 -> v2:
> >  * align related constants
> >  * drop 'int' from 'unsigned int'
> >  * add fallback to SYS_renameat where applicable
> > ---
> >  include/stdio.h       |  7 +++++++
> >  src/linux/renameat2.c | 11 +++++++++++
> >  2 files changed, 18 insertions(+)
> >  create mode 100644 src/linux/renameat2.c
> >
> > diff --git a/include/stdio.h b/include/stdio.h
> > index cb858618..4ea4c170 100644
> > --- a/include/stdio.h
> > +++ b/include/stdio.h
> > @@ -158,6 +158,13 @@ char *ctermid(char *);
> >  #define L_ctermid 20
> >  #endif
> >
> > +#if defined(_GNU_SOURCE)
> > +#define RENAME_NOREPLACE (1 << 0)
> > +#define RENAME_EXCHANGE  (1 << 1)
> > +#define RENAME_WHITEOUT  (1 << 2)
> > +
> > +int renameat2(int, const char *, int, const char *, unsigned);
> > +#endif
> >
> >  #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
> >   || defined(_BSD_SOURCE)
> > diff --git a/src/linux/renameat2.c b/src/linux/renameat2.c
> > new file mode 100644
> > index 00000000..b8060388
> > --- /dev/null
> > +++ b/src/linux/renameat2.c
> > @@ -0,0 +1,11 @@
> > +#define _GNU_SOURCE
> > +#include <stdio.h>
> > +#include "syscall.h"
> > +
> > +int renameat2(int oldfd, const char *old, int newfd, const char *new,
> > unsigned flags)
> > +{
> > +#ifdef SYS_renameat
> > +       if (!flags) return syscall(SYS_renameat, oldfd, old, newfd, new);
> > +#endif
> > +       return syscall(SYS_renameat2, oldfd, old, newfd, new, flags);
> > +}
> > --
> > 2.34.1