migration (incoming): add error propagation to fd and exec protocols

And remove the superfluous integer return value.

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

migration-exec.c

@@ -92,19 +92,17 @@ static void exec_accept_incoming_migration(void *opaque)
     qemu_fclose(f);
 }
 
-int exec_start_incoming_migration(const char *command)
+void exec_start_incoming_migration(const char *command, Error **errp)
 {
     QEMUFile *f;
 
     DPRINTF("Attempting to start an incoming migration\n");
     f = qemu_popen_cmd(command, "r");
     if(f == NULL) {
-        DPRINTF("Unable to apply qemu wrapper to popen file\n");
-        return -errno;
+        error_setg_errno(errp, errno, "failed to popen the migration source");
+        return;
     }
 
     qemu_set_fd_handler2(qemu_stdio_fd(f), NULL,
 			 exec_accept_incoming_migration, NULL, f);
-
-    return 0;
 }

migration-fd.c

@@ -97,7 +97,7 @@ static void fd_accept_incoming_migration(void *opaque)
     qemu_fclose(f);
 }
 
-int fd_start_incoming_migration(const char *infd)
+void fd_start_incoming_migration(const char *infd, Error **errp)
 {
     int fd;
     QEMUFile *f;
@@ -107,11 +107,9 @@ int fd_start_incoming_migration(const char *infd)
     fd = strtol(infd, NULL, 0);
     f = qemu_fdopen(fd, "rb");
     if(f == NULL) {
-        DPRINTF("Unable to apply qemu wrapper to file descriptor\n");
-        return -errno;
+        error_setg_errno(errp, errno, "failed to open the source descriptor");
+        return;
     }
 
     qemu_set_fd_handler2(fd, NULL, fd_accept_incoming_migration, NULL, f);
-
-    return 0;
 }

migration-tcp.c

@@ -111,18 +111,15 @@ out2:
     close(s);
 }
 
-int tcp_start_incoming_migration(const char *host_port, Error **errp)
+void tcp_start_incoming_migration(const char *host_port, Error **errp)
 {
     int s;
 
     s = inet_listen(host_port, NULL, 256, SOCK_STREAM, 0, errp);
-
     if (s < 0) {
-        return -1;
+        return;
     }
 
     qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
                          (void *)(intptr_t)s);
-
-    return 0;
 }

migration-unix.c

@@ -111,16 +111,15 @@ out2:
     close(s);
 }
 
-int unix_start_incoming_migration(const char *path, Error **errp)
+void unix_start_incoming_migration(const char *path, Error **errp)
 {
     int s;
 
     s = unix_listen(path, NULL, 0, errp);
     if (s < 0) {
-        return -1;
+        return;
     }
 
     qemu_set_fd_handler2(s, NULL, unix_accept_incoming_migration, NULL,
                          (void *)(intptr_t)s);
-    return 0;
 }

migration.c

@@ -64,26 +64,23 @@ MigrationState *migrate_get_current(void)
     return &current_migration;
 }
 
-int qemu_start_incoming_migration(const char *uri, Error **errp)
+void qemu_start_incoming_migration(const char *uri, Error **errp)
 {
     const char *p;
-    int ret;
 
     if (strstart(uri, "tcp:", &p))
-        ret = tcp_start_incoming_migration(p, errp);
+        tcp_start_incoming_migration(p, errp);
 #if !defined(WIN32)
     else if (strstart(uri, "exec:", &p))
-        ret =  exec_start_incoming_migration(p);
+        exec_start_incoming_migration(p, errp);
     else if (strstart(uri, "unix:", &p))
-        ret = unix_start_incoming_migration(p, errp);
+        unix_start_incoming_migration(p, errp);
     else if (strstart(uri, "fd:", &p))
-        ret = fd_start_incoming_migration(p);
+        fd_start_incoming_migration(p, errp);
 #endif
     else {
-        fprintf(stderr, "unknown migration protocol: %s\n", uri);
-        ret = -EPROTONOSUPPORT;
+        error_setg(errp, "unknown migration protocol: %s\n", uri);
     }
-    return ret;
 }
 
 void process_incoming_migration(QEMUFile *f)

migration.h

@@ -49,7 +49,7 @@ struct MigrationState
 
 void process_incoming_migration(QEMUFile *f);
 
-int qemu_start_incoming_migration(const char *uri, Error **errp);
+void qemu_start_incoming_migration(const char *uri, Error **errp);
 
 uint64_t migrate_max_downtime(void);
 
@@ -57,19 +57,19 @@ void do_info_migrate_print(Monitor *mon, const QObject *data);
 
 void do_info_migrate(Monitor *mon, QObject **ret_data);
 
-int exec_start_incoming_migration(const char *host_port);
+void exec_start_incoming_migration(const char *host_port, Error **errp);
 
 void exec_start_outgoing_migration(MigrationState *s, const char *host_port, Error **errp);
 
-int tcp_start_incoming_migration(const char *host_port, Error **errp);
+void tcp_start_incoming_migration(const char *host_port, Error **errp);
 
 void tcp_start_outgoing_migration(MigrationState *s, const char *host_port, Error **errp);
 
-int unix_start_incoming_migration(const char *path, Error **errp);
+void unix_start_incoming_migration(const char *path, Error **errp);
 
 void unix_start_outgoing_migration(MigrationState *s, const char *path, Error **errp);
 
-int fd_start_incoming_migration(const char *path);
+void fd_start_incoming_migration(const char *path, Error **errp);
 
 void fd_start_outgoing_migration(MigrationState *s, const char *fdname, Error **errp);
 

vl.c

@@ -3766,16 +3766,12 @@ int main(int argc, char **argv, char **envp)
     }
 
     if (incoming) {
-        Error *errp = NULL;
-        int ret = qemu_start_incoming_migration(incoming, &errp);
-        if (ret < 0) {
-            if (error_is_set(&errp)) {
-                fprintf(stderr, "Migrate: %s\n", error_get_pretty(errp));
-                error_free(errp);
-            }
-            fprintf(stderr, "Migration failed. Exit code %s(%d), exiting.\n",
-                    incoming, ret);
-            exit(ret);
+        Error *local_err = NULL;
+        qemu_start_incoming_migration(incoming, &local_err);
+        if (local_err) {
+            fprintf(stderr, "-incoming %s: %s\n", incoming, error_get_pretty(local_err));
+            error_free(local_err);
+            exit(1);
         }
     } else if (autostart) {
         vm_start();