[RFC v5 077/126] net: introduce ERRP_AUTO_PROPAGATE

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

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>
---
 net/can/can_host.c  |  7 +++----
 net/dump.c          | 15 ++++++---------
 net/filter-buffer.c | 15 ++++++---------
 net/filter.c        |  7 +++----
 net/net.c           | 41 +++++++++++++++++----------------------
 net/netmap.c        |  7 +++----
 net/tap.c           | 47 ++++++++++++++++++---------------------------
 7 files changed, 58 insertions(+), 81 deletions(-)

diff --git a/net/can/can_host.c b/net/can/can_host.c
index 1dfaf0ced0..ddbfdb8bac 100644
--- a/net/can/can_host.c
+++ b/net/can/can_host.c
@@ -50,12 +50,11 @@ static void can_host_disconnect(CanHostState *ch)
 
 static void can_host_connect(CanHostState *ch, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     CanHostClass *chc = CAN_HOST_GET_CLASS(ch);
-    Error *local_err = NULL;
 
-    chc->connect(ch, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    chc->connect(ch, errp);
+    if (*errp) {
         return;
     }
 
diff --git a/net/dump.c b/net/dump.c
index 23b3628dde..57d665b10d 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -191,23 +191,20 @@ static void filter_dump_get_maxlen(Object *obj, Visitor *v, const char *name,
 static void filter_dump_set_maxlen(Object *obj, Visitor *v, const char *name,
                                    void *opaque, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NetFilterDumpState *nfds = FILTER_DUMP(obj);
-    Error *local_err = NULL;
     uint32_t value;
 
-    visit_type_uint32(v, name, &value, &local_err);
-    if (local_err) {
-        goto out;
+    visit_type_uint32(v, name, &value, errp);
+    if (*errp) {
+        return;
     }
     if (value == 0) {
-        error_setg(&local_err, "Property '%s.%s' doesn't take value '%u'",
+        error_setg(errp, "Property '%s.%s' doesn't take value '%u'",
                    object_get_typename(obj), name, value);
-        goto out;
+        return;
     }
     nfds->maxlen = value;
-
-out:
-    error_propagate(errp, local_err);
 }
 
 static char *file_dump_get_filename(Object *obj, Error **errp)
diff --git a/net/filter-buffer.c b/net/filter-buffer.c
index 88da78f821..ac798ba421 100644
--- a/net/filter-buffer.c
+++ b/net/filter-buffer.c
@@ -169,23 +169,20 @@ static void filter_buffer_set_interval(Object *obj, Visitor *v,
                                        const char *name, void *opaque,
                                        Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     FilterBufferState *s = FILTER_BUFFER(obj);
-    Error *local_err = NULL;
     uint32_t value;
 
-    visit_type_uint32(v, name, &value, &local_err);
-    if (local_err) {
-        goto out;
+    visit_type_uint32(v, name, &value, errp);
+    if (*errp) {
+        return;
     }
     if (!value) {
-        error_setg(&local_err, "Property '%s.%s' requires a positive value",
+        error_setg(errp, "Property '%s.%s' requires a positive value",
                    object_get_typename(obj), name);
-        goto out;
+        return;
     }
     s->interval = value;
-
-out:
-    error_propagate(errp, local_err);
 }
 
 static void filter_buffer_init(Object *obj)
diff --git a/net/filter.c b/net/filter.c
index 4b932e79f9..7d5e457db0 100644
--- a/net/filter.c
+++ b/net/filter.c
@@ -191,11 +191,11 @@ static void netfilter_init(Object *obj)
 
 static void netfilter_complete(UserCreatable *uc, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NetFilterState *nf = NETFILTER(uc);
     NetClientState *ncs[MAX_QUEUE_NUM];
     NetFilterClass *nfc = NETFILTER_GET_CLASS(uc);
     int queues;
-    Error *local_err = NULL;
 
     if (!nf->netdev_id) {
         error_setg(errp, "Parameter 'netdev' is required");
@@ -222,9 +222,8 @@ static void netfilter_complete(UserCreatable *uc, Error **errp)
     nf->netdev = ncs[0];
 
     if (nfc->setup) {
-        nfc->setup(nf, &local_err);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        nfc->setup(nf, errp);
+        if (*errp) {
             return;
         }
     }
diff --git a/net/net.c b/net/net.c
index 9e93c3f8a1..9bad414840 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1098,9 +1098,9 @@ static void show_netdevs(void)
 
 static int net_client_init(QemuOpts *opts, bool is_netdev, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     gchar **substrings = NULL;
     void *object = NULL;
-    Error *err = NULL;
     int ret = -1;
     Visitor *v = opts_visitor_new(opts);
 
@@ -1143,13 +1143,13 @@ static int net_client_init(QemuOpts *opts, bool is_netdev, Error **errp)
     }
 
     if (is_netdev) {
-        visit_type_Netdev(v, NULL, (Netdev **)&object, &err);
+        visit_type_Netdev(v, NULL, (Netdev **)&object, errp);
     } else {
-        visit_type_NetLegacy(v, NULL, (NetLegacy **)&object, &err);
+        visit_type_NetLegacy(v, NULL, (NetLegacy **)&object, errp);
     }
 
-    if (!err) {
-        ret = net_client_init1(object, is_netdev, &err);
+    if (!*errp) {
+        ret = net_client_init1(object, is_netdev, errp);
     }
 
     if (is_netdev) {
@@ -1159,7 +1159,6 @@ static int net_client_init(QemuOpts *opts, bool is_netdev, Error **errp)
     }
 
 out:
-    error_propagate(errp, err);
     g_strfreev(substrings);
     visit_free(v);
     return ret;
@@ -1172,28 +1171,25 @@ void netdev_add(QemuOpts *opts, Error **errp)
 
 void qmp_netdev_add(QDict *qdict, QObject **ret, Error **errp)
 {
-    Error *local_err = NULL;
+    ERRP_AUTO_PROPAGATE();
     QemuOptsList *opts_list;
     QemuOpts *opts;
 
-    opts_list = qemu_find_opts_err("netdev", &local_err);
-    if (local_err) {
-        goto out;
+    opts_list = qemu_find_opts_err("netdev", errp);
+    if (*errp) {
+        return;
     }
 
-    opts = qemu_opts_from_qdict(opts_list, qdict, &local_err);
-    if (local_err) {
-        goto out;
+    opts = qemu_opts_from_qdict(opts_list, qdict, errp);
+    if (*errp) {
+        return;
     }
 
-    netdev_add(opts, &local_err);
-    if (local_err) {
+    netdev_add(opts, errp);
+    if (*errp) {
         qemu_opts_del(opts);
-        goto out;
+        return;
     }
-
-out:
-    error_propagate(errp, local_err);
 }
 
 void qmp_netdev_del(const char *id, Error **errp)
@@ -1348,17 +1344,16 @@ void hmp_info_network(Monitor *mon, const QDict *qdict)
 
 void colo_notify_filters_event(int event, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     NetClientState *nc;
     NetFilterState *nf;
     NetFilterClass *nfc = NULL;
-    Error *local_err = NULL;
 
     QTAILQ_FOREACH(nc, &net_clients, next) {
         QTAILQ_FOREACH(nf, &nc->filters, next) {
             nfc = NETFILTER_GET_CLASS(OBJECT(nf));
-            nfc->handle_event(nf, event, &local_err);
-            if (local_err) {
-                error_propagate(errp, local_err);
+            nfc->handle_event(nf, event, errp);
+            if (*errp) {
                 return;
             }
         }
diff --git a/net/netmap.c b/net/netmap.c
index 350f097f91..42982445be 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -406,15 +406,14 @@ static NetClientInfo net_netmap_info = {
 int net_init_netmap(const Netdev *netdev,
                     const char *name, NetClientState *peer, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const NetdevNetmapOptions *netmap_opts = &netdev->u.netmap;
     struct nm_desc *nmd;
     NetClientState *nc;
-    Error *err = NULL;
     NetmapState *s;
 
-    nmd = netmap_open(netmap_opts, &err);
-    if (err) {
-        error_propagate(errp, err);
+    nmd = netmap_open(netmap_opts, errp);
+    if (*errp) {
         return -1;
     }
     /* Create the object. */
diff --git a/net/tap.c b/net/tap.c
index 6207f61f84..b03146605d 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -610,7 +610,7 @@ static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
                         const char *setup_script, char *ifname,
                         size_t ifname_sz, int mq_required, Error **errp)
 {
-    Error *err = NULL;
+    ERRP_AUTO_PROPAGATE();
     int fd, vnet_hdr_required;
 
     if (tap->has_vnet_hdr) {
@@ -630,9 +630,8 @@ static int net_tap_init(const NetdevTapOptions *tap, int *vnet_hdr,
     if (setup_script &&
         setup_script[0] != '\0' &&
         strcmp(setup_script, "no") != 0) {
-        launch_script(setup_script, ifname, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+        launch_script(setup_script, ifname, fd, errp);
+        if (*errp) {
             close(fd);
             return -1;
         }
@@ -649,13 +648,12 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
                              const char *downscript, const char *vhostfdname,
                              int vnet_hdr, int fd, Error **errp)
 {
-    Error *err = NULL;
+    ERRP_AUTO_PROPAGATE();
     TAPState *s = net_tap_fd_init(peer, model, name, fd, vnet_hdr);
     int vhostfd;
 
-    tap_set_sndbuf(s->fd, tap, &err);
-    if (err) {
-        error_propagate(errp, err);
+    tap_set_sndbuf(s->fd, tap, errp);
+    if (*errp) {
         return;
     }
 
@@ -689,12 +687,11 @@ static void net_init_tap_one(const NetdevTapOptions *tap, NetClientState *peer,
         }
 
         if (vhostfdname) {
-            vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
+            vhostfd = monitor_fd_param(cur_mon, vhostfdname, errp);
             if (vhostfd == -1) {
                 if (tap->has_vhostforce && tap->vhostforce) {
-                    error_propagate(errp, err);
                 } else {
-                    warn_report_err(err);
+                    warn_report_errp(errp);
                 }
                 return;
             }
@@ -758,12 +755,12 @@ static int get_fds(char *str, char *fds[], int max)
 int net_init_tap(const Netdev *netdev, const char *name,
                  NetClientState *peer, Error **errp)
 {
+    ERRP_AUTO_PROPAGATE();
     const NetdevTapOptions *tap;
     int fd, vnet_hdr = 0, i = 0, queues;
     /* for the no-fd, no-helper case */
     const char *script = NULL; /* suppress wrong "uninit'd use" gcc warning */
     const char *downscript = NULL;
-    Error *err = NULL;
     const char *vhostfdname;
     char ifname[128];
 
@@ -789,9 +786,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
             return -1;
         }
 
-        fd = monitor_fd_param(cur_mon, tap->fd, &err);
+        fd = monitor_fd_param(cur_mon, tap->fd, errp);
         if (fd == -1) {
-            error_propagate(errp, err);
             return -1;
         }
 
@@ -801,9 +797,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
 
         net_init_tap_one(tap, peer, "tap", name, NULL,
                          script, downscript,
-                         vhostfdname, vnet_hdr, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+                         vhostfdname, vnet_hdr, fd, errp);
+        if (*errp) {
             return -1;
         }
     } else if (tap->has_fds) {
@@ -836,9 +831,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
         }
 
         for (i = 0; i < nfds; i++) {
-            fd = monitor_fd_param(cur_mon, fds[i], &err);
+            fd = monitor_fd_param(cur_mon, fds[i], errp);
             if (fd == -1) {
-                error_propagate(errp, err);
                 ret = -1;
                 goto free_fail;
             }
@@ -857,9 +851,8 @@ int net_init_tap(const Netdev *netdev, const char *name,
             net_init_tap_one(tap, peer, "tap", name, ifname,
                              script, downscript,
                              tap->has_vhostfds ? vhost_fds[i] : NULL,
-                             vnet_hdr, fd, &err);
-            if (err) {
-                error_propagate(errp, err);
+                             vnet_hdr, fd, errp);
+            if (*errp) {
                 ret = -1;
                 goto free_fail;
             }
@@ -896,9 +889,8 @@ free_fail:
 
         net_init_tap_one(tap, peer, "bridge", name, ifname,
                          script, downscript, vhostfdname,
-                         vnet_hdr, fd, &err);
-        if (err) {
-            error_propagate(errp, err);
+                         vnet_hdr, fd, errp);
+        if (*errp) {
             close(fd);
             return -1;
         }
@@ -935,9 +927,8 @@ free_fail:
             net_init_tap_one(tap, peer, "tap", name, ifname,
                              i >= 1 ? "no" : script,
                              i >= 1 ? "no" : downscript,
-                             vhostfdname, vnet_hdr, fd, &err);
-            if (err) {
-                error_propagate(errp, err);
+                             vhostfdname, vnet_hdr, fd, errp);
+            if (*errp) {
                 close(fd);
                 return -1;
             }
-- 
2.21.0