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

[Vladimir Sementsov-Ogievskiy]

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 <address@hidden>
Reported-by: Greg Kurz <address@hidden>
Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
---
 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;
     }
 
-- 
2.21.0