Re: [PATCH 2/2 v2] xenstore: check F_SETFL fcntl invocation in setnonblock

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 30/11/2013 00:30, Matthew Daley wrote:
> ...and check the newly-added result of setnonblock itself where used.
>
> Coverity-ID: 1055103
> Signed-off-by: Matthew Daley <mattd@bugfuzz.com>

Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>

> ---
> v2: return false -> goto out_false
>
>  tools/xenstore/xs.c |   16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
> index 184886f..504d524 100644
> --- a/tools/xenstore/xs.c
> +++ b/tools/xenstore/xs.c
> @@ -146,20 +146,17 @@ struct xs_handle {
>  
>  static int read_message(struct xs_handle *h, int nonblocking);
>  
> -static void setnonblock(int fd, int nonblock) {
> -	int esave = errno;
> +static bool setnonblock(int fd, int nonblock) {
>  	int flags = fcntl(fd, F_GETFL);
>  	if (flags == -1)
> -		goto out;
> +		return false;
>  
>  	if (nonblock)
>  		flags |= O_NONBLOCK;
>  	else
>  		flags &= ~O_NONBLOCK;
>  
> -	fcntl(fd, F_SETFL, flags);
> -out:
> -	errno = esave;
> +	return fcntl(fd, F_SETFL, flags) != -1;
>  }
>  
>  int xs_fileno(struct xs_handle *h)
> @@ -369,8 +366,8 @@ static bool read_all(int fd, void *data, unsigned int len, int nonblocking)
>  	if (!len)
>  		return true;
>  
> -	if (nonblocking)
> -		setnonblock(fd, 1);
> +	if (nonblocking && !setnonblock(fd, 1))
> +		return false;
>  
>  	while (len) {
>  		int done;
> @@ -390,8 +387,9 @@ static bool read_all(int fd, void *data, unsigned int len, int nonblocking)
>  		len -= done;
>  
>  		if (nonblocking) {
> -			setnonblock(fd, 0);
>  			nonblocking = 0;
> +			if (!setnonblock(fd, 0))
> +				goto out_false;
>  		}
>  	}
>