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

[Matthew Daley <mattd@xxxxxxxxxxx>]

Ping?

On Tue, Dec 3, 2013 at 1:45 AM, Matthew Daley <mattd@xxxxxxxxxxx> wrote:
> ...and check the newly-added result of setnonblock itself where used.
>
> Coverity-ID: 1055103
> Signed-off-by: Matthew Daley <mattd@xxxxxxxxxxx>
> ---
> v2: Use a constant value for the final setnonblock return, instead of a
> side-effecting expression
>
>  tools/xenstore/xs.c |   19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
>
> diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
> index 184886f..a636498 100644
> --- a/tools/xenstore/xs.c
> +++ b/tools/xenstore/xs.c
> @@ -146,20 +146,20 @@ 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;
> +       if (fcntl(fd, F_SETFL, flags) == -1)
> +               return false;
> +
> +       return true;
>  }
>
>  int xs_fileno(struct xs_handle *h)
> @@ -369,8 +369,8 @@ 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 +390,9 @@ 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;
>                 }
>         }
>
> --
> 1.7.10.4
>

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