[RFC,v5,075/126] Main loop: introduce ERRP_AUTO_PROPAGATE

If we want to add some info to errp (by error_prepend() or
error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
Otherwise, this info will not be added when errp == &fatal_err
(the program will exit prior to the error_append_hint() or
error_prepend() call).  Fix such cases.

If we want to check error after errp-function call, we need to
introduce local_err and than propagate it to errp. Instead, use
ERRP_AUTO_PROPAGATE macro, benefits are:
1. No need of explicit error_propagate call
2. No need of explicit local_err variable: use errp directly
3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
   &error_fatel, this means that we don't break error_abort
   (we'll abort on error_set, not on error_propagate)

This commit (together with its neighbors) was generated by

for f in $(git grep -l errp \*.[ch]); do \
    spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
    --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
done;

then fix a bit of compilation problems: coccinelle for some reason
leaves several
f() {
    ...
    goto out;
    ...
    out:
}
patterns, with "out:" at function end.

then
./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"

(auto-msg was a file with this commit message)

Still, for backporting it may be more comfortable to use only the first
command and then do one huge commit.

Reported-by: Kevin Wolf <kwolf@redhat.com>
Reported-by: Greg Kurz <groug@kaod.org>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 util/main-loop.c |  5 ++---
 vl.c             | 14 ++++++--------
 2 files changed, 8 insertions(+), 11 deletions(-)

On 10/11/19 6:05 PM, Vladimir Sementsov-Ogievskiy wrote:
> If we want to add some info to errp (by error_prepend() or
> error_append_hint()), we must use the ERRP_AUTO_PROPAGATE macro.
> Otherwise, this info will not be added when errp == &fatal_err
> (the program will exit prior to the error_append_hint() or
> error_prepend() call).  Fix such cases.
> 
> If we want to check error after errp-function call, we need to
> introduce local_err and than propagate it to errp. Instead, use
> ERRP_AUTO_PROPAGATE macro, benefits are:
> 1. No need of explicit error_propagate call
> 2. No need of explicit local_err variable: use errp directly
> 3. ERRP_AUTO_PROPAGATE leaves errp as is if it's not NULL or
>     &error_fatel, this means that we don't break error_abort
>     (we'll abort on error_set, not on error_propagate)
> 
> This commit (together with its neighbors) was generated by
> 
> for f in $(git grep -l errp \*.[ch]); do \
>      spatch --sp-file scripts/coccinelle/auto-propagated-errp.cocci \
>      --macro-file scripts/cocci-macro-file.h --in-place --no-show-diff $f; \
> done;
> 
> then fix a bit of compilation problems: coccinelle for some reason
> leaves several
> f() {
>      ...
>      goto out;
>      ...
>      out:
> }
> patterns, with "out:" at function end.
> 
> then
> ./python/commit-per-subsystem.py MAINTAINERS "$(< auto-msg)"
> 
> (auto-msg was a file with this commit message)
> 
> Still, for backporting it may be more comfortable to use only the first
> command and then do one huge commit.
> 
> Reported-by: Kevin Wolf <kwolf@redhat.com>
> Reported-by: Greg Kurz <groug@kaod.org>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>   util/main-loop.c |  5 ++---
>   vl.c             | 14 ++++++--------
>   2 files changed, 8 insertions(+), 11 deletions(-)
> 
> diff --git a/util/main-loop.c b/util/main-loop.c
> index e3eaa55866..fdd7f50fc8 100644
> --- a/util/main-loop.c
> +++ b/util/main-loop.c
> @@ -145,9 +145,9 @@ static GArray *gpollfds;
>   
>   int qemu_init_main_loop(Error **errp)
>   {
> +    ERRP_AUTO_PROPAGATE();
>       int ret;
>       GSource *src;
> -    Error *local_error = NULL;
>   
>       init_clocks(qemu_timer_notify_cb);
>   
> @@ -156,9 +156,8 @@ int qemu_init_main_loop(Error **errp)
>           return ret;
>       }
>   
> -    qemu_aio_context = aio_context_new(&local_error);
> +    qemu_aio_context = aio_context_new(errp);
>       if (!qemu_aio_context) {
> -        error_propagate(errp, local_error);
>           return -EMFILE;
>       }
>       qemu_notify_bh = qemu_bh_new(notify_event_cb, NULL);
> diff --git a/vl.c b/vl.c
> index 002bf4919e..7499ff5691 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2213,11 +2213,10 @@ static int device_init_func(void *opaque, QemuOpts *opts, Error **errp)
>   
>   static int chardev_init_func(void *opaque, QemuOpts *opts, Error **errp)
>   {
> -    Error *local_err = NULL;
> +    ERRP_AUTO_PROPAGATE();
>   
> -    if (!qemu_chr_new_from_opts(opts, NULL, &local_err)) {
> -        if (local_err) {
> -            error_propagate(errp, local_err);
> +    if (!qemu_chr_new_from_opts(opts, NULL, errp)) {
> +        if (*errp) {
>               return -1;
>           }
>           exit(0);
> @@ -2613,8 +2612,8 @@ static int machine_set_property(void *opaque,
>                                   const char *name, const char *value,
>                                   Error **errp)
>   {
> +    ERRP_AUTO_PROPAGATE();
>       Object *obj = OBJECT(opaque);
> -    Error *local_err = NULL;
>       char *p, *qom_name;
>   
>       if (strcmp(name, "type") == 0) {
> @@ -2628,11 +2627,10 @@ static int machine_set_property(void *opaque,
>           }
>       }
>   
> -    object_property_parse(obj, value, qom_name, &local_err);
> +    object_property_parse(obj, value, qom_name, errp);
>       g_free(qom_name);
>   
> -    if (local_err) {
> -        error_propagate(errp, local_err);
> +    if (*errp) {
>           return -1;
>       }
>   
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>