Re: [PATCH v2] chardev: don't exit() straight away on C-a x

[Paolo Bonzini]

On 19/10/21 11:29, Alex Bennée wrote:
> While there are a number of uses in the code-base of the exit(0)
> pattern it gets in the way of clean exit which can do all of it's
> house-keeping. In particular it was reported that you can crash
> plugins this way because TCG can still be running on other threads
> when the atexit callback is called.
>
> Use qmp_quit() instead which takes care of some housekeeping before
> triggering the shutdown.
>
> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> Reported-by: Lukas Jünger <lukas.junger@greensocs.com>
> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> Message-Id: <20211018140226.838137-1-alex.bennee@linaro.org>
>
> ---
> v2
>    - use qmp_quit instead of direct qemu_system_shutdown_request
>    - g_assert_not_reached() for the stub definition

Either g_assert_not_reached() or exit(0) should be okay, so

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks,

Paolo

> ---
>   chardev/char-mux.c | 3 ++-
>   stubs/qmp-quit.c   | 8 ++++++++
>   stubs/meson.build  | 1 +
>   3 files changed, 11 insertions(+), 1 deletion(-)
>   create mode 100644 stubs/qmp-quit.c
>
> diff --git a/chardev/char-mux.c b/chardev/char-mux.c
> index ada0c6866f..ee2d47b20d 100644
> --- a/chardev/char-mux.c
> +++ b/chardev/char-mux.c
> @@ -28,6 +28,7 @@
>   #include "qemu/option.h"
>   #include "chardev/char.h"
>   #include "sysemu/block-backend.h"
> +#include "qapi/qapi-commands-control.h"
>   #include "chardev-internal.h"
>   
>   /* MUX driver for serial I/O splitting */
> @@ -157,7 +158,7 @@ static int mux_proc_byte(Chardev *chr, MuxChardev *d, int 
> ch)
>               {
>                    const char *term =  "QEMU: Terminated\n\r";
>                    qemu_chr_write_all(chr, (uint8_t *)term, strlen(term));
> -                 exit(0);
> +                 qmp_quit(NULL);
>                    break;
>               }
>           case 's':
> diff --git a/stubs/qmp-quit.c b/stubs/qmp-quit.c
> new file mode 100644
> index 0000000000..a3ff47f7bd
> --- /dev/null
> +++ b/stubs/qmp-quit.c
> @@ -0,0 +1,8 @@
> +#include "qemu/osdep.h"
> +#include "qapi/qapi-commands-control.h"
> +#include "qapi/qmp/dispatch.h"
> +
> +void qmp_quit(Error **errp)
> +{
> +    g_assert_not_reached();
> +}
> diff --git a/stubs/meson.build b/stubs/meson.build
> index f6aa3aa94f..71469c1d50 100644
> --- a/stubs/meson.build
> +++ b/stubs/meson.build
> @@ -31,6 +31,7 @@ stub_ss.add(files('pci-bus.c'))
>   stub_ss.add(files('qemu-timer-notify-cb.c'))
>   stub_ss.add(files('qmp_memory_device.c'))
>   stub_ss.add(files('qmp-command-available.c'))
> +stub_ss.add(files('qmp-quit.c'))
>   stub_ss.add(files('qtest.c'))
>   stub_ss.add(files('ram-block.c'))
>   stub_ss.add(files('ramfb.c'))