uname -m/-p for compat32 binaries

[Scott Long]

We do something similar at yahoo, and it's code that we're working on packaging up to put back into FreeBSD.  I don't know how your code differs from ours, and I obviously cannot stop you from committing yours, but you're welcome to look at our code.

Scott

On Jul 19, 2010, at 3:30 PM, Kostik Belousov wrote:

> Hi,
> I intend to commit the following change, that makes sysctls
> hw.machine_arch and hw.machine to return "i386" for 32 bit
> binaries run on amd64. In particular, 32 bit uname -m and uname -p
> print "i386", that is good for i386 jails on amd64 kernels.
> 
> I find the change very useful for me, but I wonder why such trivial
> modification is not yet done. Can anybody note a possible fallout from
> it ?
> 
> diff --git a/sys/amd64/amd64/identcpu.c b/sys/amd64/amd64/identcpu.c
> index 52e7568..68de22b 100644
> --- a/sys/amd64/amd64/identcpu.c
> +++ b/sys/amd64/amd64/identcpu.c
> @@ -76,8 +76,26 @@ static void print_via_padlock_info(void);
> 
> int	cpu_class;
> char machine[] = "amd64";
> -SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD, 
> -    machine, 0, "Machine class");
> +
> +static int
> +sysctl_hw_machine(SYSCTL_HANDLER_ARGS)
> +{
> +#ifdef SCTL_MASK32
> +	static const char machine32[] = "i386";
> +#endif
> +	int error;
> +
> +#ifdef SCTL_MASK32
> +	if ((req->flags & SCTL_MASK32) != 0)
> +		error = SYSCTL_OUT(req, machine32, sizeof(machine32));
> +	else
> +#endif
> +		error = SYSCTL_OUT(req, machine, sizeof(machine));
> +	return (error);
> +
> +}
> +SYSCTL_PROC(_hw, HW_MACHINE, machine, CTLTYPE_STRING | CTLFLAG_RD,
> +    NULL, 0, sysctl_hw_machine, "A", "Machine class");
> 
> static char cpu_model[128];
> SYSCTL_STRING(_hw, HW_MODEL, model, CTLFLAG_RD, 
> diff --git a/sys/kern/kern_mib.c b/sys/kern/kern_mib.c
> index 7ef580f..0b7d27f 100644
> --- a/sys/kern/kern_mib.c
> +++ b/sys/kern/kern_mib.c
> @@ -232,9 +232,31 @@ sysctl_hw_pagesizes(SYSCTL_HANDLER_ARGS)
> SYSCTL_PROC(_hw, OID_AUTO, pagesizes, CTLTYPE_ULONG | CTLFLAG_RD,
>     NULL, 0, sysctl_hw_pagesizes, "LU", "Supported page sizes");
> 
> -static char	machine_arch[] = MACHINE_ARCH;
> -SYSCTL_STRING(_hw, HW_MACHINE_ARCH, machine_arch, CTLFLAG_RD,
> -    machine_arch, 0, "System architecture");
> +static int
> +sysctl_hw_machine_arch(SYSCTL_HANDLER_ARGS)
> +{
> +	static const char machine_arch[] = MACHINE_ARCH;
> +#ifdef SCTL_MASK32
> +	static const char machine_arch32[] = 
> +#if defined(__amd64__) || defined(__ia64__)
> +		"i386";
> +#else
> +		MACHINE_ARCH;
> +#endif
> +#endif
> +	int error;
> +
> +#ifdef SCTL_MASK32
> +	if ((req->flags & SCTL_MASK32) != 0)
> +		error = SYSCTL_OUT(req, machine_arch32, sizeof(machine_arch32));
> +	else
> +#endif
> +		error = SYSCTL_OUT(req, machine_arch, sizeof(machine_arch));
> +	return (error);
> +
> +}
> +SYSCTL_PROC(_hw, HW_MACHINE_ARCH, machine_arch, CTLTYPE_STRING | CTLFLAG_RD,
> +    NULL, 0, sysctl_hw_machine_arch, "A", "System architecture");
> 
> static int
> sysctl_hostname(SYSCTL_HANDLER_ARGS)