[PATCH V4 16/19] tests/qtest: defer connection

[Steve Sistare <steven.sistare@oracle.com>]

Add an option to defer making the connecting to the monitor and qtest
sockets when calling qtest_init_with_env.  The client makes the connection
later by calling qtest_connect_deferred and qtest_qmp_handshake.

A test cannot specify port=0 for a deferred connection, because qmp_migrate
cannot query for the assigned port, because the monitor is not connected
yet.  However, even if the test does not specify port=0, qmp_migrate ->
migrate_set_ports unconditionally queries connection parameters.
Modify migrate_set_ports to only query when port=0.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 tests/qtest/libqtest.c          | 80 +++++++++++++++++++++++++----------------
 tests/qtest/libqtest.h          | 19 +++++++++-
 tests/qtest/migration-helpers.c | 19 +++++-----
 tests/qtest/migration-test.c    |  4 +--
 4 files changed, 80 insertions(+), 42 deletions(-)

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 817fd7a..31c4032 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -75,6 +75,8 @@ struct QTestState
 {
     int fd;
     int qmp_fd;
+    int sock;
+    int qmpsock;
     pid_t qemu_pid;  /* our child QEMU process */
     int wstatus;
 #ifdef _WIN32
@@ -442,18 +444,19 @@ static QTestState *G_GNUC_PRINTF(2, 3) qtest_spawn_qemu(const char *qemu_bin,
     return s;
 }
 
+static char *qtest_socket_path(const char *suffix)
+{
+    return g_strdup_printf("%s/qtest-%d.%s", g_get_tmp_dir(), getpid(), suffix);
+}
+
 static QTestState *qtest_init_internal(const char *qemu_bin,
-                                       const char *extra_args)
+                                       const char *extra_args,
+                                       bool defer_connect)
 {
     QTestState *s;
     int sock, qmpsock, i;
-    gchar *socket_path;
-    gchar *qmp_socket_path;
-
-    socket_path = g_strdup_printf("%s/qtest-%d.sock",
-                                  g_get_tmp_dir(), getpid());
-    qmp_socket_path = g_strdup_printf("%s/qtest-%d.qmp",
-                                      g_get_tmp_dir(), getpid());
+    g_autofree gchar *socket_path = qtest_socket_path("sock");
+    g_autofree gchar *qmp_socket_path = qtest_socket_path("qmp");
 
     /*
      * It's possible that if an earlier test run crashed it might
@@ -485,22 +488,17 @@ static QTestState *qtest_init_internal(const char *qemu_bin,
     qtest_client_set_rx_handler(s, qtest_client_socket_recv_line);
     qtest_client_set_tx_handler(s, qtest_client_socket_send);
 
-    s->fd = socket_accept(sock);
-    if (s->fd >= 0) {
-        s->qmp_fd = socket_accept(qmpsock);
-    }
-    unlink(socket_path);
-    unlink(qmp_socket_path);
-    g_free(socket_path);
-    g_free(qmp_socket_path);
-
-    g_assert(s->fd >= 0 && s->qmp_fd >= 0);
-
     s->rx = g_string_new("");
     for (i = 0; i < MAX_IRQ; i++) {
         s->irq_level[i] = false;
     }
 
+    s->sock = sock;
+    s->qmpsock = qmpsock;
+    if (!defer_connect) {
+        qtest_connect_deferred(s);
+    }
+
     /*
      * Stopping QEMU for debugging is not supported on Windows.
      *
@@ -515,34 +513,54 @@ static QTestState *qtest_init_internal(const char *qemu_bin,
     }
 #endif
 
+   return s;
+}
+
+void qtest_connect_deferred(QTestState *s)
+{
+    g_autofree gchar *socket_path = qtest_socket_path("sock");
+    g_autofree gchar *qmp_socket_path = qtest_socket_path("qmp");
+
+    g_assert(s->sock >= 0 && s->qmpsock >= 0);
+    s->fd = socket_accept(s->sock);
+    if (s->fd >= 0) {
+        s->qmp_fd = socket_accept(s->qmpsock);
+    }
+    unlink(socket_path);
+    unlink(qmp_socket_path);
+    g_assert(s->fd >= 0 && s->qmp_fd >= 0);
+    s->sock = s->qmpsock = -1;
     /* ask endianness of the target */
-
     s->big_endian = qtest_query_target_endianness(s);
-
-   return s;
 }
 
 QTestState *qtest_init_without_qmp_handshake(const char *extra_args)
 {
-    return qtest_init_internal(qtest_qemu_binary(NULL), extra_args);
+    return qtest_init_internal(qtest_qemu_binary(NULL), extra_args, false);
 }
 
-QTestState *qtest_init_with_env(const char *var, const char *extra_args)
+void qtest_qmp_handshake(QTestState *s)
 {
-    QTestState *s = qtest_init_internal(qtest_qemu_binary(var), extra_args);
-    QDict *greeting;
-
     /* Read the QMP greeting and then do the handshake */
-    greeting = qtest_qmp_receive(s);
+    QDict *greeting = qtest_qmp_receive(s);
     qobject_unref(greeting);
     qobject_unref(qtest_qmp(s, "{ 'execute': 'qmp_capabilities' }"));
+}
 
+QTestState *qtest_init_with_env(const char *var, const char *extra_args,
+                                bool defer_connect)
+{
+    QTestState *s = qtest_init_internal(qtest_qemu_binary(var), extra_args,
+                                        defer_connect);
+    if (!defer_connect) {
+        qtest_qmp_handshake(s);
+    }
     return s;
 }
 
 QTestState *qtest_init(const char *extra_args)
 {
-    return qtest_init_with_env(NULL, extra_args);
+    return qtest_init_with_env(NULL, extra_args, false);
 }
 
 QTestState *qtest_vinitf(const char *fmt, va_list ap)
@@ -1523,7 +1541,7 @@ static struct MachInfo *qtest_get_machines(const char *var)
 
     silence_spawn_log = !g_test_verbose();
 
-    qts = qtest_init_with_env(qemu_var, "-machine none");
+    qts = qtest_init_with_env(qemu_var, "-machine none", false);
     response = qtest_qmp(qts, "{ 'execute': 'query-machines' }");
     g_assert(response);
     list = qdict_get_qlist(response, "return");
@@ -1578,7 +1596,7 @@ static struct CpuModel *qtest_get_cpu_models(void)
 
     silence_spawn_log = !g_test_verbose();
 
-    qts = qtest_init_with_env(NULL, "-machine none");
+    qts = qtest_init_with_env(NULL, "-machine none", false);
     response = qtest_qmp(qts, "{ 'execute': 'query-cpu-definitions' }");
     g_assert(response);
     list = qdict_get_qlist(response, "return");
diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
index beb96b1..db76f2c 100644
--- a/tests/qtest/libqtest.h
+++ b/tests/qtest/libqtest.h
@@ -60,13 +60,15 @@ QTestState *qtest_init(const char *extra_args);
  * @var: Environment variable from where to take the QEMU binary
  * @extra_args: Other arguments to pass to QEMU.  CAUTION: these
  * arguments are subject to word splitting and shell evaluation.
+ * @defer_connect: do not connect to qemu monitor and qtest socket.
  *
  * Like qtest_init(), but use a different environment variable for the
  * QEMU binary.
  *
  * Returns: #QTestState instance.
  */
-QTestState *qtest_init_with_env(const char *var, const char *extra_args);
+QTestState *qtest_init_with_env(const char *var, const char *extra_args,
+                                bool defer_connect);
 
 /**
  * qtest_init_without_qmp_handshake:
@@ -78,6 +80,21 @@ QTestState *qtest_init_with_env(const char *var, const char *extra_args);
 QTestState *qtest_init_without_qmp_handshake(const char *extra_args);
 
 /**
+ * qtest_connect_deferred:
+ * @s: #QTestState instance to connect
+ * Connect to qemu monitor and qtest socket, after deferring them in
+ * qtest_init_with_env.  Does not handshake with the monitor.
+ */
+void qtest_connect_deferred(QTestState *s);
+
+/**
+ * qtest_qmp_handshake:
+ * @s: #QTestState instance to operate on.
+ * Perform handshake after connecting to qemu monitor.
+ */
+void qtest_qmp_handshake(QTestState *s);
+
+/**
  * qtest_init_with_serial:
  * @extra_args: other arguments to pass to QEMU.  CAUTION: these
  * arguments are subject to word splitting and shell evaluation.
diff --git a/tests/qtest/migration-helpers.c b/tests/qtest/migration-helpers.c
index 3f8ba7f..9f39401 100644
--- a/tests/qtest/migration-helpers.c
+++ b/tests/qtest/migration-helpers.c
@@ -127,25 +127,28 @@ migrate_get_connect_qdict(QTestState *who)
 
 static void migrate_set_ports(QTestState *to, QList *channel_list)
 {
-    QDict *addr;
+    g_autoptr(QDict) addr = NULL;
     QListEntry *entry;
     const char *addr_port = NULL;
 
-    addr = migrate_get_connect_qdict(to);
-
     QLIST_FOREACH_ENTRY(channel_list, entry) {
         QDict *channel = qobject_to(QDict, qlist_entry_obj(entry));
         QDict *addrdict = qdict_get_qdict(channel, "addr");
 
-        if (qdict_haskey(addrdict, "port") &&
-            qdict_haskey(addr, "port") &&
-            (strcmp(qdict_get_str(addrdict, "port"), "0") == 0)) {
+        if (!qdict_haskey(addrdict, "port") ||
+            strcmp(qdict_get_str(addrdict, "port"), "0")) {
+            continue;
+        }
+
+        if (!addr) {
+            addr = migrate_get_connect_qdict(to);
+        }
+
+        if (qdict_haskey(addr, "port")) {
             addr_port = qdict_get_str(addr, "port");
             qdict_put_str(addrdict, "port", addr_port);
         }
     }
-
-    qobject_unref(addr);
 }
 
 bool migrate_watch_for_events(QTestState *who, const char *name,
diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
index 64e1c50..b7001b0 100644
--- a/tests/qtest/migration-test.c
+++ b/tests/qtest/migration-test.c
@@ -844,7 +844,7 @@ static int test_migrate_start(QTestState **from, QTestState **to,
                                  args->opts_source ? args->opts_source : "",
                                  ignore_stderr);
     if (!args->only_target) {
-        *from = qtest_init_with_env(QEMU_ENV_SRC, cmd_source);
+        *from = qtest_init_with_env(QEMU_ENV_SRC, cmd_source, false);
         qtest_qmp_set_event_callback(*from,
                                      migrate_watch_for_events,
                                      &src_state);
@@ -865,7 +865,7 @@ static int test_migrate_start(QTestState **from, QTestState **to,
                                  shmem_opts ? shmem_opts : "",
                                  args->opts_target ? args->opts_target : "",
                                  ignore_stderr);
-    *to = qtest_init_with_env(QEMU_ENV_DST, cmd_target);
+    *to = qtest_init_with_env(QEMU_ENV_DST, cmd_target, false);
     qtest_qmp_set_event_callback(*to,
                                  migrate_watch_for_events,
                                  &dst_state);
-- 
1.8.3.1