net: Permit incremental conversion of init functions to Error

Error reporting for netdev_add is broken: the net_client_init_fun[]
report the actual errors with (at best) error_report(), and their
caller net_client_init1() makes up a generic error on top.

For command line and HMP, this produces an mildly ugly error cascade.

In QMP, the actual errors go to stderr, and the generic error becomes
the command's error reply.

To fix this, we need to convert the net_client_init_fun[] to Error.

To permit fixing them one by one, add an Error ** parameter to the
net_client_init_fun[].  If the call fails without returning an Error,
make up the same generic Error as before.  But if it returns one, use
that instead.  Since none of them does so far, no functional change.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-id: 1431691143-1015-3-git-send-email-armbru@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

12 files changed, 40 insertions, 29 deletions

diff --git a/net/clients.h b/net/clients.h
index 2e8fedad8d..d47530e82f 100644
--- a/net/clients.h
+++ b/net/clients.h
@@ -28,38 +28,38 @@
 #include "qapi-types.h"
 
 int net_init_dump(const NetClientOptions *opts, const char *name,
-                  NetClientState *peer);
+                  NetClientState *peer, Error **errp);
 
 #ifdef CONFIG_SLIRP
 int net_init_slirp(const NetClientOptions *opts, const char *name,
-                   NetClientState *peer);
+                   NetClientState *peer, Error **errp);
 #endif
 
 int net_init_hubport(const NetClientOptions *opts, const char *name,
-                     NetClientState *peer);
+                     NetClientState *peer, Error **errp);
 
 int net_init_socket(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer);
+                    NetClientState *peer, Error **errp);
 
 int net_init_tap(const NetClientOptions *opts, const char *name,
-                 NetClientState *peer);
+                 NetClientState *peer, Error **errp);
 
 int net_init_bridge(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer);
+                    NetClientState *peer, Error **errp);
 
 int net_init_l2tpv3(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer);
+                    NetClientState *peer, Error **errp);
 #ifdef CONFIG_VDE
 int net_init_vde(const NetClientOptions *opts, const char *name,
-                 NetClientState *peer);
+                 NetClientState *peer, Error **errp);
 #endif
 
 #ifdef CONFIG_NETMAP
 int net_init_netmap(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer);
+                    NetClientState *peer, Error **errp);
 #endif
 
 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
-                        NetClientState *peer);
+                        NetClientState *peer, Error **errp);
 
 #endif /* QEMU_NET_CLIENTS_H */
diff --git a/net/dump.c b/net/dump.c
index 9d3a09e334..214e88a768 100644
--- a/net/dump.c
+++ b/net/dump.c
@@ -146,8 +146,9 @@ static int net_dump_init(NetClientState *peer, const char *device,
 }
 
 int net_init_dump(const NetClientOptions *opts, const char *name,
-                  NetClientState *peer)
+                  NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     int len;
     const char *file;
     char def_file[128];
diff --git a/net/hub.c b/net/hub.c
index 261f8ccc3f..3047f12766 100644
--- a/net/hub.c
+++ b/net/hub.c
@@ -281,7 +281,7 @@ int net_hub_id_for_client(NetClientState *nc, int *id)
 }
 
 int net_init_hubport(const NetClientOptions *opts, const char *name,
-                     NetClientState *peer)
+                     NetClientState *peer, Error **errp)
 {
     const NetdevHubPortOptions *hubport;
 
diff --git a/net/l2tpv3.c b/net/l2tpv3.c
index 8c598b09bc..ed395dc126 100644
--- a/net/l2tpv3.c
+++ b/net/l2tpv3.c
@@ -536,10 +536,9 @@ static NetClientInfo net_l2tpv3_info = {
 
 int net_init_l2tpv3(const NetClientOptions *opts,
                     const char *name,
-                    NetClientState *peer)
+                    NetClientState *peer, Error **errp)
 {
-
-
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevL2TPv3Options *l2tpv3;
     NetL2TPV3State *s;
     NetClientState *nc;
diff --git a/net/net.c b/net/net.c
index d9aaeb5341..3295741d1d 100644
--- a/net/net.c
+++ b/net/net.c
@@ -740,8 +740,9 @@ int qemu_find_nic_model(NICInfo *nd, const char * const *models,
 }
 
 static int net_init_nic(const NetClientOptions *opts, const char *name,
-                        NetClientState *peer)
+                        NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     int idx;
     NICInfo *nd;
     const NetLegacyNicOptions *nic;
@@ -809,7 +810,7 @@ static int net_init_nic(const NetClientOptions *opts, const char *name,
 static int (* const net_client_init_fun[NET_CLIENT_OPTIONS_KIND_MAX])(
     const NetClientOptions *opts,
     const char *name,
-    NetClientState *peer) = {
+    NetClientState *peer, Error **errp) = {
         [NET_CLIENT_OPTIONS_KIND_NIC]       = net_init_nic,
 #ifdef CONFIG_SLIRP
         [NET_CLIENT_OPTIONS_KIND_USER]      = net_init_slirp,
@@ -902,10 +903,12 @@ static int net_client_init1(const void *object, int is_netdev, Error **errp)
             peer = net_hub_add_port(u.net->has_vlan ? u.net->vlan : 0, NULL);
         }
 
-        if (net_client_init_fun[opts->kind](opts, name, peer) < 0) {
-            /* TODO push error reporting into init() methods */
-            error_set(errp, QERR_DEVICE_INIT_FAILED,
-                      NetClientOptionsKind_lookup[opts->kind]);
+        if (net_client_init_fun[opts->kind](opts, name, peer, errp) < 0) {
+            /* FIXME drop when all init functions store an Error */
+            if (errp && !*errp) {
+                error_set(errp, QERR_DEVICE_INIT_FAILED,
+                          NetClientOptionsKind_lookup[opts->kind]);
+            }
             return -1;
         }
     }
diff --git a/net/netmap.c b/net/netmap.c
index 0c1772b03f..69300eb1ae 100644
--- a/net/netmap.c
+++ b/net/netmap.c
@@ -446,8 +446,9 @@ static NetClientInfo net_netmap_info = {
  * ... -net netmap,ifname="..."
  */
 int net_init_netmap(const NetClientOptions *opts,
-        const char *name, NetClientState *peer)
+                    const char *name, NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevNetmapOptions *netmap_opts = opts->netmap;
     NetClientState *nc;
     NetmapPriv me;
diff --git a/net/slirp.c b/net/slirp.c
index 9bbed7447a..0e15cf6750 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -737,8 +737,9 @@ static const char **slirp_dnssearch(const StringList *dnsname)
 }
 
 int net_init_slirp(const NetClientOptions *opts, const char *name,
-                   NetClientState *peer)
+                   NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     struct slirp_config_str *config;
     char *vnet;
     int ret;
diff --git a/net/socket.c b/net/socket.c
index c30e03f5ae..5a19aa1881 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -693,8 +693,9 @@ static int net_socket_udp_init(NetClientState *peer,
 }
 
 int net_init_socket(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer)
+                    NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     Error *err = NULL;
     const NetdevSocketOptions *sock;
 
diff --git a/net/tap-win32.c b/net/tap-win32.c
index 8aee611f7d..f6fc9610a7 100644
--- a/net/tap-win32.c
+++ b/net/tap-win32.c
@@ -752,8 +752,9 @@ static int tap_win32_init(NetClientState *peer, const char *model,
 }
 
 int net_init_tap(const NetClientOptions *opts, const char *name,
-                 NetClientState *peer)
+                 NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevTapOptions *tap;
 
     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_TAP);
diff --git a/net/tap.c b/net/tap.c
index 968df46c8c..8f06cb7382 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -531,8 +531,9 @@ static int net_bridge_run_helper(const char *helper, const char *bridge)
 }
 
 int net_init_bridge(const NetClientOptions *opts, const char *name,
-                    NetClientState *peer)
+                    NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevBridgeOptions *bridge;
     const char *helper, *br;
 
@@ -699,8 +700,9 @@ static int get_fds(char *str, char *fds[], int max)
 }
 
 int net_init_tap(const NetClientOptions *opts, const char *name,
-                 NetClientState *peer)
+                 NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevTapOptions *tap;
     int fd, vnet_hdr = 0, i = 0, queues;
     /* for the no-fd, no-helper case */
diff --git a/net/vde.c b/net/vde.c
index 2a619fbc81..dacaa64b47 100644
--- a/net/vde.c
+++ b/net/vde.c
@@ -110,8 +110,9 @@ static int net_vde_init(NetClientState *peer, const char *model,
 }
 
 int net_init_vde(const NetClientOptions *opts, const char *name,
-                 NetClientState *peer)
+                 NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevVdeOptions *vde;
 
     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_VDE);
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 1d86a2be11..11899c53c0 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -223,8 +223,9 @@ static int net_vhost_check_net(QemuOpts *opts, void *opaque)
 }
 
 int net_init_vhost_user(const NetClientOptions *opts, const char *name,
-                        NetClientState *peer)
+                        NetClientState *peer, Error **errp)
 {
+    /* FIXME error_setg(errp, ...) on failure */
     const NetdevVhostUserOptions *vhost_user_opts;
     CharDriverState *chr;