Re: [PATCH 5/8] util, pasta: Use __clone2() instead of clone() on ia64

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

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On Tue, Nov 15, 2022 at 02:23:46AM +0100, Stefano Brivio wrote:
> On ia64, clone(2) is not available: the glibc wrapper is named
> __clone2() and it takes, additionally, the size of the stack area
> passed by the caller.
> 
> Spotted in Debian's buildd logs.
> 
> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Urgh, I'd really prefer to make our own wrapper to reduce two ifdefs
to one.

> ---
>  pasta.c |  9 +++++++++
>  util.h  | 12 ++++++++++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/pasta.c b/pasta.c
> index db86317..1f3afa1 100644
> --- a/pasta.c
> +++ b/pasta.c
> @@ -226,11 +226,20 @@ void pasta_start_ns(struct ctx *c, uid_t uid, gid_t gid,
>  		arg.argv = sh_argv;
>  	}
>  
> +#ifdef __ia64__
> +	pasta_child_pid = __clone2(pasta_spawn_cmd,
> +				   ns_fn_stack + sizeof(ns_fn_stack) / 2,
> +				   sizeof(ns_fn_stack) / 2,
> +				   CLONE_NEWIPC | CLONE_NEWPID | CLONE_NEWNET |
> +				   CLONE_NEWUTS,
> +				   (void *)&arg);
> +#else
>  	pasta_child_pid = clone(pasta_spawn_cmd,
>  				ns_fn_stack + sizeof(ns_fn_stack) / 2,
>  				CLONE_NEWIPC | CLONE_NEWPID | CLONE_NEWNET |
>  				CLONE_NEWUTS,
>  				(void *)&arg);
> +#endif
>  
>  	if (pasta_child_pid == -1) {
>  		perror("clone");
> diff --git a/util.h b/util.h
> index 2d4e1ff..3c48992 100644
> --- a/util.h
> +++ b/util.h
> @@ -81,6 +81,17 @@
>  	(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
>  
>  #define NS_FN_STACK_SIZE	(RLIMIT_STACK_VAL * 1024 / 8)
> +#ifdef __ia64__
> +#define NS_CALL(fn, arg)						\
> +	do {								\
> +		char ns_fn_stack[NS_FN_STACK_SIZE];			\
> +									\
> +		__clone2((fn), ns_fn_stack + sizeof(ns_fn_stack) / 2,	\
> +			 sizeof(ns_fn_stack) / 2,			\
> +			 CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,\
> +			 (void *)(arg));				\
> +	} while (0)
> +#else
>  #define NS_CALL(fn, arg)						\
>  	do {								\
>  		char ns_fn_stack[NS_FN_STACK_SIZE];			\
> @@ -89,6 +100,7 @@
>  		      CLONE_VM | CLONE_VFORK | CLONE_FILES | SIGCHLD,	\
>  		      (void *)(arg));					\
>  	} while (0)
> +#endif
>  
>  #if __BYTE_ORDER == __BIG_ENDIAN
>  #define L2_BUF_ETH_IP4_INIT						\

-- 
David Gibson			| 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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