svn commit: r321790 - head/sbin/sysctl

[John Baldwin]

On Monday, July 31, 2017 02:56:35 PM Andrew Gallatin wrote:
> Author: gallatin
> Date: Mon Jul 31 14:56:35 2017
> New Revision: 321790
> URL: https://svnweb.freebsd.org/changeset/base/321790
> 
> Log:
>   Don't request CTLTYPE_OPAQUE if we can't print them.
>   
>   The intent is to skip expensive opaque sysctls like tcp_pcblist unless
>   they are explicitly requested. Sysctl nodes like this don't show up in
>   sysctl -a, but they do generate output that winds up being dropped,
>   unless the user specifically requested  binary/hex output or opaques.
>   
>   This reduces the runtime of sysctl in many circumstances on a loaded
>   system.  It also reduces the likelihood that simply gathering
>   diagnostics on a sick machine (stuck lock, etc) via sysctl -a might
>   push it over the edge into a total lockup.
>   
>   Reviewed by:	jtl
>   Sponsored by:	Netflix
>   Differential Revision:	https://reviews.freebsd.org/D11461
> 
> Modified:
>   head/sbin/sysctl/sysctl.c
> 
> Modified: head/sbin/sysctl/sysctl.c
> ==============================================================================
> --- head/sbin/sysctl/sysctl.c	Mon Jul 31 14:53:03 2017	(r321789)
> +++ head/sbin/sysctl/sysctl.c	Mon Jul 31 14:56:35 2017	(r321790)
> @@ -925,6 +925,32 @@ show_var(int *oid, int nlen)
>  		printf("%s", buf);
>  		return (0);
>  	}
> +
> +	/* don't fetch opaques that we don't know how to print */
> +	if (ctltype == CTLTYPE_OPAQUE) {
> +		if (strcmp(fmt, "S,clockinfo") == 0)
> +			func = S_clockinfo;
> +		else if (strcmp(fmt, "S,timeval") == 0)
> +			func = S_timeval;
> +		else if (strcmp(fmt, "S,loadavg") == 0)
> +			func = S_loadavg;
> +		else if (strcmp(fmt, "S,vmtotal") == 0)
> +			func = S_vmtotal;
> +#ifdef __amd64__
> +		else if (strcmp(fmt, "S,efi_map_header") == 0)
> +			func = S_efi_map;
> +#endif
> +#if defined(__amd64__) || defined(__i386__)
> +		else if (strcmp(fmt, "S,bios_smap_xattr") == 0)
> +			func = S_bios_smap_xattr;
> +#endif
> +		else {
> +			func = NULL;
> +			if (!bflag && !oflag && !xflag)
> +				return (1);
> +		}
> +	}
> +
>  	/* find an estimate of how much we need for this var */
>  	if (Bflag)
>  		j = Bflag;
> @@ -1045,24 +1071,6 @@ show_var(int *oid, int nlen)
>  
>  	case CTLTYPE_OPAQUE:
>  		i = 0;
> -		if (strcmp(fmt, "S,clockinfo") == 0)
> -			func = S_clockinfo;
> -		else if (strcmp(fmt, "S,timeval") == 0)
> -			func = S_timeval;
> -		else if (strcmp(fmt, "S,loadavg") == 0)
> -			func = S_loadavg;
> -		else if (strcmp(fmt, "S,vmtotal") == 0)
> -			func = S_vmtotal;
> -#ifdef __amd64__
> -		else if (strcmp(fmt, "S,efi_map_header") == 0)
> -			func = S_efi_map;
> -#endif
> -#if defined(__amd64__) || defined(__i386__)
> -		else if (strcmp(fmt, "S,bios_smap_xattr") == 0)
> -			func = S_bios_smap_xattr;
> -#endif
> -		else
> -			func = NULL;
>  		if (func) {

func should always be true now?

-- 
John Baldwin