svn commit: r285782 - head/usr.bin/netstat

[Mark Johnston]

On Tue, Jul 28, 2015 at 05:31:06PM +0300, Gleb Smirnoff wrote:
>   Mark, Jason,
> 
> On Tue, Jul 21, 2015 at 11:57:39PM +0000, Mark Johnston wrote:
> M>   Fix counter reads on platforms where sizeof(uint64_t) != sizeof(uint64_t *).
> M>   
> M>   In the kernel, structs such as tcpstat are manipulated as an array of
> M>   counter_u64_t (uint64_t *), but made visible to userland as an array of
> M>   uint64_t. kread_counters() was previously copying the counter array into
> M>   user space and sequentially overwriting each counter with its value. This
> M>   mostly affects IPsec counters, as other counters are exported via sysctl.
> M>   
> M>   PR:		201700
> M>   Tested by:	Jason Unovitch
> 
> Thanks for fixing the bug after me.
> 
> One question, though: why do you use sizeof(u_long) instead of size of a
> pointer?

kvm_counter_u64_fetch(3) takes a u_long for the KVA of the counter, so it
seemed natural to read an array of counter addresses into an array of
u_long.

> 
> M> ==============================================================================
> M> --- head/usr.bin/netstat/main.c	Tue Jul 21 23:44:36 2015	(r285781)
> M> +++ head/usr.bin/netstat/main.c	Tue Jul 21 23:57:38 2015	(r285782)
> M> @@ -776,19 +776,31 @@ kread_counter(u_long addr)
> M>  int
> M>  kread_counters(u_long addr, void *buf, size_t size)
> M>  {
> M> -	uint64_t *c = buf;
> M> +	uint64_t *c;
> M> +	u_long *counters;
> M> +	size_t i, n;
> M>  
> M>  	if (kvmd_init() < 0)
> M>  		return (-1);
> M>  
> M> -	if (kread(addr, buf, size) < 0)
> M> +	if (size % sizeof(uint64_t) != 0) {
> M> +		xo_warnx("kread_counters: invalid counter set size");
> M>  		return (-1);
> M> +	}
> M>  
> M> -	while (size != 0) {
> M> -		*c = kvm_counter_u64_fetch(kvmd, *c);
> M> -		size -= sizeof(*c);
> M> -		c++;
> M> +	n = size / sizeof(uint64_t);
> M> +	if ((counters = malloc(n * sizeof(u_long))) == NULL)
> M> +		xo_err(-1, "malloc");
> M> +	if (kread(addr, counters, n * sizeof(u_long)) < 0) {
> M> +		free(counters);
> M> +		return (-1);
> M>  	}
> M> +
> M> +	c = buf;
> M> +	for (i = 0; i < n; i++)
> M> +		c[i] = kvm_counter_u64_fetch(kvmd, counters[i]);
> M> +
> M> +	free(counters);
> M>  	return (0);
> M>  }
> 
> -- 
> Totus tuus, Glebius.