Re: [PATCH 3/8] linux_dep: Move close_range() conditional handling to linux_dep.h

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, Nov 06, 2024 at 08:10:53PM +0100, Stefano Brivio wrote:
> On Wed,  6 Nov 2024 17:54:16 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > util.h has some #ifdefs and weak definitions to handle compatibility with
> > various kernel versions.  Move this to linux_dep.h which handles several
> > other similar cases.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  linux_dep.h | 20 ++++++++++++++++++++
> >  util.h      | 19 -------------------
> >  2 files changed, 20 insertions(+), 19 deletions(-)
> > 
> > diff --git a/linux_dep.h b/linux_dep.h
> > index eae9c3c..3a41e42 100644
> > --- a/linux_dep.h
> > +++ b/linux_dep.h
> > @@ -125,4 +125,24 @@ struct tcp_info_linux {
> >  #define FALLOC_FL_COLLAPSE_RANGE	0x08
> >  #endif
> >  
> > +#include <linux/close_range.h>
> > +
> > +#ifdef CLOSE_RANGE_UNSHARE	/* Linux kernel >= 5.9 */
> > +/* glibc < 2.34 and musl as of 1.2.5 need these */
> > +#ifndef SYS_close_range
> > +#define SYS_close_range		436
> > +#endif
> > +__attribute__ ((weak))
> > +/* cppcheck-suppress funcArgNamesDifferent */
> > +int close_range(unsigned int first, unsigned int last, int flags) {
> > +	return syscall(SYS_close_range, first, last, flags);
> > +}
> > +#else
> > +/* No reasonable fallback option */
> > +/* cppcheck-suppress funcArgNamesDifferent */
> > +int close_range(unsigned int first, unsigned int last, int flags) {
> > +	return 0;
> > +}
> > +#endif
> > +
> >  #endif /* LINUX_DEP_H */
> > diff --git a/util.h b/util.h
> > index 2858b10..fdc3af8 100644
> > --- a/util.h
> > +++ b/util.h
> > @@ -17,7 +17,6 @@
> >  #include <arpa/inet.h>
> >  #include <unistd.h>
> >  #include <sys/syscall.h>
> > -#include <linux/close_range.h>
> >  
> >  #include "log.h"
> >  
> > @@ -158,24 +157,6 @@ int do_clone(int (*fn)(void *), char *stack_area, size_t stack_size, int flags,
> >  
> >  struct ctx;
> >  
> > -#ifdef CLOSE_RANGE_UNSHARE	/* Linux kernel >= 5.9 */
> > -/* glibc < 2.34 and musl as of 1.2.5 need these */
> > -#ifndef SYS_close_range
> > -#define SYS_close_range		436
> > -#endif
> > -__attribute__ ((weak))
> > -/* cppcheck-suppress funcArgNamesDifferent */
> > -int close_range(unsigned int first, unsigned int last, int flags) {
> > -	return syscall(SYS_close_range, first, last, flags);
> > -}
> > -#else
> > -/* No reasonable fallback option */
> > -/* cppcheck-suppress funcArgNamesDifferent */
> > -int close_range(unsigned int first, unsigned int last, int flags) {
> > -	return 0;
> > -}
> > -#endif
> > -
> 
> This breaks the build on Alpine as well:
> 
> util.c: In function 'close_open_files':
> util.c:729:22: error: implicit declaration of function 'close_range'; did you mean 'SYS_close_range'? [-Wimplicit-function-declaration]
>   729 |                 rc = close_range(STDERR_FILENO + 1, ~0U, CLOSE_RANGE_UNSHARE);
>       |                      ^~~~~~~~~~~
>       |                      SYS_close_range
> util.c:729:58: error: 'CLOSE_RANGE_UNSHARE' undeclared (first use in this function)
>   729 |                 rc = close_range(STDERR_FILENO + 1, ~0U, CLOSE_RANGE_UNSHARE);
>       |                                                          ^~~~~~~~~~~~~~~~~~~
> 
> and is fixed by including "linux_dep.h" from util.c.

Oops again, adjusted.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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