Re: [Qemu-devel] [PATCH 1/1] libqtest: Improve error reporting for bad read from QEMU

[Paolo Bonzini <pbonzini@redhat.com>]

On 15/08/2018 16:19, Markus Armbruster wrote:
> When read() from the qtest socket or the QMP socket fails or EOFs, we
> report "Broken pipe" and exit(1).  This commonly happens when QEMU
> crashes.  It also happens when QEMU refuses to run because the test
> passed it bad arguments.  Sadly, we neglect to report either.
> 
> Improve this by calling abort() instead of exit(1), so kill_qemu()
> runs, and reports how QEMU died.  This improves error reporting to
> something like
> 
>     /x86_64/device/introspect/list: Broken pipe
>     tests/libqtest.c:129: kill_qemu() detected QEMU death from signal 6 (Aborted) (dumped core)
> 
> Three exit() remain in libqtest.c:
> 
> * In qmp_response(), when we can't parse a QMP reply read from the QMP
>   socket.  Change to abort() for consistency.
> 
> * In qtest_qemu_binary(), when QTEST_QEMU_BINARY isn't in the
>   environment.  This can only happen before we start QEMU.  Leave
>   alone.
> 
> * In qtest_init_without_qmp_handshake(), when the fork()ed child fails
>   to execlp().  Leave alone.
> 
> exit() elsewhere are unlikely due to QEMU dying on us.  If that should
> turn out to be wrong, we can move kill_qemu() from the abrt handler to
> atexit() or something.
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>  tests/libqtest.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/libqtest.c b/tests/libqtest.c
> index b703fca26d..852ccff1ce 100644
> --- a/tests/libqtest.c
> +++ b/tests/libqtest.c
> @@ -367,7 +367,7 @@ static GString *qtest_recv_line(QTestState *s)
>  
>          if (len == -1 || len == 0) {
>              fprintf(stderr, "Broken pipe\n");
> -            exit(1);
> +            abort();
>          }
>  
>          g_string_append_len(s->rx, buffer, len);
> @@ -454,7 +454,7 @@ static void qmp_response(JSONMessageParser *parser, GQueue *tokens)
>      obj = json_parser_parse(tokens, NULL);
>      if (!obj) {
>          fprintf(stderr, "QMP JSON response parsing failed\n");
> -        exit(1);
> +        abort();
>      }
>  
>      g_assert(!qmp->response);
> @@ -480,7 +480,7 @@ QDict *qmp_fd_receive(int fd)
>  
>          if (len == -1 || len == 0) {
>              fprintf(stderr, "Broken pipe\n");
> -            exit(1);
> +            abort();
>          }
>  
>          if (log) {
> 

Queued, thanks.

Paolo