qemu-sockets: add error propagation to inet_connect_addr

perror and fprintf can be removed because all clients can now consume
Errors properly.  However, we'll need to change the non-blocking connect
handlers to take an Error, in order to improve error handling for
migration with the TCP protocol.

This is a minor degradation in error reporting for outgoing migration.
However, until 1.2 this case just failed without even attempting to
connect, so it is still an improvement as far as overall QoI is
concerned.
Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

qemu-sockets.c

@@ -216,7 +216,7 @@ typedef struct ConnectState {
 } ConnectState;
 
 static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
-                             ConnectState *connect_state);
+                             ConnectState *connect_state, Error **errp);
 
 static void wait_for_connect(void *opaque)
 {
@@ -246,7 +246,7 @@ static void wait_for_connect(void *opaque)
     if (s->current_addr) {
         while (s->current_addr->ai_next != NULL && s->fd < 0) {
             s->current_addr = s->current_addr->ai_next;
-            s->fd = inet_connect_addr(s->current_addr, &in_progress, s);
+            s->fd = inet_connect_addr(s->current_addr, &in_progress, s, NULL);
             /* connect in progress */
             if (in_progress) {
                 return;
@@ -263,7 +263,7 @@ static void wait_for_connect(void *opaque)
 }
 
 static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
-                             ConnectState *connect_state)
+                             ConnectState *connect_state, Error **errp)
 {
     int sock, rc;
 
@@ -271,8 +271,7 @@ static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
 
     sock = qemu_socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
     if (sock < 0) {
-        fprintf(stderr, "%s: socket(%s): %s\n", __func__,
-                inet_strfamily(addr->ai_family), strerror(errno));
+        error_set_errno(errp, errno, QERR_SOCKET_CREATE_FAILED);
         return -1;
     }
     qemu_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
@@ -293,6 +292,7 @@ static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
                              connect_state);
         *in_progress = true;
     } else if (rc < 0) {
+        error_set_errno(errp, errno, QERR_SOCKET_CONNECT_FAILED);
         closesocket(sock);
         return -1;
     }
@@ -375,7 +375,7 @@ int inet_connect_opts(QemuOpts *opts, Error **errp,
         if (connect_state != NULL) {
             connect_state->current_addr = e;
         }
-        sock = inet_connect_addr(e, &in_progress, connect_state);
+        sock = inet_connect_addr(e, &in_progress, connect_state, errp);
         if (in_progress) {
             return sock;
         } else if (sock >= 0) {
@@ -386,9 +386,6 @@ int inet_connect_opts(QemuOpts *opts, Error **errp,
             break;
         }
     }
-    if (sock < 0) {
-        error_set(errp, QERR_SOCKET_CONNECT_FAILED);
-    }
     g_free(connect_state);
     freeaddrinfo(res);
     return sock;