Re: [PATCH V7 5/7] perf buildid-cache: add ability to add kcore to the cache

[Arnaldo Carvalho de Melo <acme@ghostprotocols.net>]

Em Mon, Oct 14, 2013 at 01:43:42PM +0300, Adrian Hunter escreveu:
> +static int kcore_copy__compare_fds(int from, int to)
<SNIP>
> +	while (1) {
> +		/* Use read because mmap won't work on proc files */
> +		ret = read(from, buf_from, page_size);
> +		if (ret < 0)
> +			return -1;
> +		if (!ret)
> +			return 0;
> +		n = ret;
> +		len = ret;
> +		while (n) {
> +			ret = read(to, buf_to, n);
> +			if (ret <= 0)
> +				return -1;
> +			n -= ret;

You can't go on potentially rewriting 'buf_to' like that, consider using
readn().

> +		}
> +
> +		if (memcmp(buf_from, buf_to, len))
> +			return -1;
> +	}
> +}