[PATCH 04/11] memcpy cmd: Do not expect to read/write the whole chunk at once

[Sascha Hauer]

On Fri, Jun 25, 2010 at 09:17:44AM +0200, Peter Korsgaard wrote:
> >>>>> "Sascha" == Sascha Hauer <s.hauer at pengutronix.de> writes:
> 
> Hi,
> 
>  Sascha> read() does not necessarily return the number of bytes
>  Sascha> we want to read, so deal with less bytes.
> 
>  Sascha> -		if ((w = write(destfd, rw_buf, r)) < 0) {
>  Sascha> -			perror("write");
>  Sascha> -			goto out;
>  Sascha> -		}
>  Sascha> -
>  Sascha> -		if (r < now)
>  Sascha> +		if (!r)
>  Sascha>  			break;
>  
>  Sascha> -		if (w < r)
>  Sascha> -			break;
>  Sascha> +		tmp = 0;
>  Sascha> +		now = r;
>  Sascha> +		while (now) {
>  Sascha> +			w = write(destfd, rw_buf + tmp, now);
>  Sascha> +			if (w < 0) {
>  Sascha> +				perror("write");
>  Sascha> +				goto out;
>  Sascha> +			}
>  Sascha> +	                if (!w)
>  Sascha> +			        break;
>  
>  Sascha> -		count -= now;
>  Sascha> +			now -= w;
>  Sascha> +			tmp += w;
>  Sascha> +		}
>  Sascha> +
> 
> This is probably not the only place we need this. What about moving this
> to a helper function like busybox' full_write()?

I merged this for now, but I'll remember it for next time I implement
such a loop.

Sascha

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