Re: [Qemu-devel] [PATCH] compatfd.c: Don't pass NULL pointer to SYS_signalfd

[Stefan Weil]

Am 13.10.2011 19:45, schrieb Peter Maydell:
> Don't pass a NULL pointer in to SYS_signalfd in qemu_signalfd_available():
> this isn't valid and Valgrind complains about it.
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
> compatfd.c | 12 ++++++++++--
> 1 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/compatfd.c b/compatfd.c
> index 31654c6..02306a4 100644
> --- a/compatfd.c
> +++ b/compatfd.c
> @@ -119,9 +119,17 @@ int qemu_signalfd(const sigset_t *mask)
> bool qemu_signalfd_available(void)
> {
> #ifdef CONFIG_SIGNALFD
> + sigset_t mask;
> + int fd;
> + bool ok;
> + sigemptyset(&mask);
> errno = 0;
> - syscall(SYS_signalfd, -1, NULL, _NSIG / 8);
> - return errno != ENOSYS;
> + fd = syscall(SYS_signalfd, -1, &mask, _NSIG / 8);
> + ok = (errno != ENOSYS);
> + if (fd >= 0) {

Maybe better: fd != -1

> + close(fd);
> + }
> + return ok;
> #else
> return false;
> #endif

The variable 'ok' is not needed, simply returning
errno != ENOSYS would work, too.

Regards,
Stefan W.