On Tue, Sep 04, 2018 at 07:08:18PM +0800, Fei Li wrote:
> Currently, when qemu_signal_init() fails it only returns a non-zero
> value but without propagating any Error. But its callers need a
> non-null err when runs error_report_err(err), or else 0->msg occurs.
>
> To avoid such segmentation fault, add a new Error parameter to make
> the call trace to propagate the err to the final caller.
>
> Signed-off-by: Fei Li <f...@suse.com>
> ---
> include/qemu/osdep.h | 2 +-
> util/compatfd.c | 17 ++++++++++++-----
> util/main-loop.c | 11 +++++++----
> 3 files changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
> index a91068df0e..09ed85fcb8 100644
> --- a/include/qemu/osdep.h
> +++ b/include/qemu/osdep.h
> @@ -421,7 +421,7 @@ struct qemu_signalfd_siginfo {
> additional fields in the future) */
> };
>
> -int qemu_signalfd(const sigset_t *mask);
> +int qemu_signalfd(const sigset_t *mask, Error **errp);
> void sigaction_invoke(struct sigaction *action,
> struct qemu_signalfd_siginfo *info);
> #endif
> diff --git a/util/compatfd.c b/util/compatfd.c
> index 980bd33e52..65501de622 100644
> --- a/util/compatfd.c
> +++ b/util/compatfd.c
> @@ -16,6 +16,7 @@
> #include "qemu/osdep.h"
> #include "qemu-common.h"
> #include "qemu/thread.h"
> +#include "qapi/error.h"
>
> #include <sys/syscall.h>
>
> @@ -65,7 +66,7 @@ static void *sigwait_compat(void *opaque)
> }
> }
>
> -static int qemu_signalfd_compat(const sigset_t *mask)
> +static int qemu_signalfd_compat(const sigset_t *mask, Error **errp)
> {
> struct sigfd_compat_info *info;
> QemuThread thread;
> @@ -73,11 +74,13 @@ static int qemu_signalfd_compat(const sigset_t *mask)
>
> info = malloc(sizeof(*info));
> if (info == NULL) {
> + error_setg(errp, "Failed to malloc in %s", __func__);
I'd avoid using __func__ in error messages. Instead
"Failed to allocate signalfd memory"
> errno = ENOMEM;
> return -1;
> }
>
> if (pipe(fds) == -1) {
> + error_setg(errp, "Failed to create a pipe in %s", __func__);
"Failed to create signalfd pipe"
> free(info);
> return -1;
> }
> @@ -94,17 +97,21 @@ static int qemu_signalfd_compat(const sigset_t *mask)
> return fds[0];
> }
>
> -int qemu_signalfd(const sigset_t *mask)
> +int qemu_signalfd(const sigset_t *mask, Error **errp)
> {
> -#if defined(CONFIG_SIGNALFD)
> int ret;
> + Error *local_err = NULL;
>
> +#if defined(CONFIG_SIGNALFD)
> ret = syscall(SYS_signalfd, -1, mask, _NSIG / 8);
> if (ret != -1) {
> qemu_set_cloexec(ret);
> return ret;
> }
> #endif
> -
> - return qemu_signalfd_compat(mask);
> + ret = qemu_signalfd_compat(mask, &local_err);
> + if (local_err) {
> + error_propagate(errp, local_err);
> + }
Using a local_err is not required - you can just pass errp stright
to qemu_signalfd_compat() and then check
if (ret < 0)
> + return ret;
> }
> diff --git a/util/main-loop.c b/util/main-loop.c
> index affe0403c5..20f6ad3849 100644
> --- a/util/main-loop.c
> +++ b/util/main-loop.c
> @@ -71,10 +71,11 @@ static void sigfd_handler(void *opaque)
> }
> }
>
> -static int qemu_signal_init(void)
> +static int qemu_signal_init(Error **errp)
> {
> int sigfd;
> sigset_t set;
> + Error *local_err = NULL;
>
> /*
> * SIG_IPI must be blocked in the main thread and must not be caught
> @@ -94,9 +95,10 @@ static int qemu_signal_init(void)
> pthread_sigmask(SIG_BLOCK, &set, NULL);
>
> sigdelset(&set, SIG_IPI);
> - sigfd = qemu_signalfd(&set);
> + sigfd = qemu_signalfd(&set, &local_err);
> if (sigfd == -1) {
> fprintf(stderr, "failed to create signalfd\n");
> + error_propagate(errp, local_err);
> return -errno;
> }
Again, no need for local_err - just pass errp stright in
>
> @@ -109,7 +111,7 @@ static int qemu_signal_init(void)
>
> #else /* _WIN32 */
>
> -static int qemu_signal_init(void)
> +static int qemu_signal_init(Error **errp)
> {
> return 0;
> }
> @@ -148,8 +150,9 @@ int qemu_init_main_loop(Error **errp)
>
> init_clocks(qemu_timer_notify_cb);
>
> - ret = qemu_signal_init();
> + ret = qemu_signal_init(&local_error);
> if (ret) {
> + error_propagate(errp, local_error);
> return ret;
> }
Again, no need for local_error.
Regards,
Daniel
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